DXR is a code search and navigation tool aimed at making sense of large projects. It supports full-text and regex searches as well as structural queries.

Header

Mercurial (5216dd412535)

VCS Links

Line Code
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549 1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579 1580 1581 1582 1583 1584 1585 1586 1587 1588 1589 1590 1591 1592 1593 1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625 1626 1627 1628 1629 1630 1631 1632 1633 1634 1635 1636 1637 1638 1639 1640 1641 1642 1643 1644 1645 1646 1647 1648 1649 1650 1651 1652 1653 1654 1655 1656 1657 1658 1659 1660 1661 1662 1663 1664 1665 1666 1667 1668 1669 1670 1671 1672 1673 1674 1675 1676 1677 1678 1679 1680 1681 1682 1683 1684 1685 1686 1687 1688 1689 1690 1691 1692 1693 1694 1695 1696 1697 1698 1699 1700 1701 1702 1703 1704 1705 1706 1707 1708 1709 1710 1711 1712 1713 1714 1715 1716 1717 1718 1719 1720 1721 1722 1723 1724 1725 1726 1727 1728 1729 1730 1731 1732 1733 1734 1735 1736 1737 1738 1739 1740 1741 1742 1743 1744 1745 1746 1747 1748 1749 1750 1751 1752 1753 1754 1755 1756 1757 1758 1759 1760 1761 1762 1763 1764 1765 1766 1767 1768 1769 1770 1771 1772 1773 1774 1775 1776 1777 1778 1779 1780 1781 1782 1783 1784 1785 1786 1787 1788 1789 1790 1791 1792 1793 1794 1795 1796 1797 1798 1799 1800 1801 1802 1803 1804 1805 1806 1807 1808 1809 1810 1811 1812 1813 1814 1815 1816 1817 1818 1819 1820 1821 1822 1823 1824 1825 1826 1827 1828 1829 1830 1831 1832 1833 1834 1835 1836 1837 1838 1839 1840 1841 1842 1843 1844 1845 1846 1847 1848 1849 1850 1851 1852 1853 1854 1855 1856 1857 1858 1859 1860 1861 1862 1863 1864 1865 1866 1867 1868 1869 1870 1871 1872 1873 1874 1875 1876 1877 1878 1879 1880 1881 1882 1883 1884 1885 1886 1887 1888 1889 1890 1891 1892 1893 1894 1895 1896 1897 1898 1899 1900 1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 1926 1927 1928 1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043 2044 2045 2046 2047 2048 2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059 2060 2061 2062 2063 2064 2065 2066 2067 2068 2069 2070 2071 2072 2073 2074 2075 2076 2077 2078 2079 2080 2081 2082 2083 2084 2085 2086 2087 2088 2089 2090 2091 2092 2093 2094 2095 2096 2097 2098 2099 2100 2101 2102 2103 2104 2105 2106 2107 2108 2109 2110 2111 2112 2113 2114 2115 2116 2117 2118 2119 2120 2121 2122 2123 2124 2125 2126 2127 2128 2129 2130 2131 2132 2133 2134 2135 2136 2137 2138 2139 2140 2141 2142 2143 2144 2145 2146 2147 2148 2149 2150 2151 2152 2153 2154 2155 2156 2157 2158 2159 2160 2161 2162 2163 2164 2165 2166 2167 2168 2169 2170 2171 2172 2173 2174 2175 2176 2177 2178 2179 2180 2181 2182 2183 2184 2185 2186 2187 2188 2189 2190 2191 2192 2193 2194 2195 2196 2197 2198 2199 2200 2201 2202 2203 2204 2205 2206 2207 2208 2209 2210 2211 2212 2213 2214 2215 2216 2217 2218 2219 2220 2221 2222 2223 2224 2225 2226 2227 2228 2229 2230 2231 2232 2233 2234 2235 2236 2237 2238 2239 2240 2241 2242 2243 2244 2245 2246 2247 2248 2249 2250 2251 2252 2253 2254 2255 2256 2257 2258 2259 2260 2261 2262 2263 2264 2265 2266 2267 2268 2269 2270 2271 2272 2273 2274 2275 2276 2277 2278 2279 2280 2281 2282 2283 2284 2285 2286 2287 2288 2289 2290 2291 2292 2293 2294 2295 2296 2297 2298 2299 2300 2301 2302 2303 2304 2305 2306 2307 2308 2309 2310 2311 2312 2313 2314 2315 2316 2317 2318 2319 2320 2321 2322 2323 2324 2325 2326 2327 2328 2329 2330 2331 2332 2333 2334 2335 2336 2337 2338 2339 2340 2341 2342 2343 2344 2345 2346 2347 2348 2349 2350 2351 2352 2353 2354 2355 2356 2357 2358 2359 2360 2361 2362 2363 2364 2365 2366 2367 2368 2369 2370 2371 2372 2373 2374 2375 2376 2377 2378 2379 2380 2381 2382 2383 2384 2385 2386 2387 2388 2389 2390 2391 2392 2393 2394 2395 2396 2397 2398 2399 2400 2401 2402 2403 2404 2405 2406 2407 2408 2409 2410 2411 2412 2413 2414 2415 2416 2417 2418 2419 2420 2421 2422 2423 2424 2425 2426 2427 2428 2429 2430 2431 2432 2433 2434 2435 2436 2437 2438 2439 2440 2441 2442 2443 2444 2445 2446 2447 2448 2449 2450 2451 2452 2453 2454 2455 2456 2457 2458 2459 2460 2461 2462 2463 2464 2465 2466 2467 2468 2469 2470 2471 2472 2473 2474 2475 2476 2477 2478 2479 2480 2481 2482 2483 2484 2485 2486 2487 2488 2489
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is Mozilla FastLoad code.
 *
 * The Initial Developer of the Original Code is
 * Netscape Communications Corporation.
 * Portions created by the Initial Developer are Copyright (C) 2001
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *   Brendan Eich <brendan@mozilla.org> (original author)
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either of the GNU General Public License Version 2 or later (the "GPL"),
 * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

#include <string.h>
#include "prtypes.h"
#include "nscore.h"
#include "nsDebug.h"
#include "nsEnumeratorUtils.h"
#include "nsMemory.h"
#include "nsXPIDLString.h"
#include "nsString.h"
#include "nsReadableUtils.h"

#include "nsIComponentManager.h"
#include "nsIFile.h"
#include "nsILocalFile.h"
#include "nsISeekableStream.h"
#include "nsISerializable.h"
#include "nsIStreamBufferAccess.h"
#include "nsIClassInfo.h"

#include "nsBinaryStream.h"
#include "nsFastLoadFile.h"
#include "nsInt64.h"
#ifdef XP_UNIX
#include <sys/mman.h>
#endif

#ifdef DEBUG_brendan
# define METERING
# define DEBUG_MUX
#endif

#ifdef METERING
# define METER(x)       x
#else
# define METER(x)       /* nothing */
#endif

#ifdef DEBUG_MUX
# include <stdio.h>
# include <stdarg.h>

static void trace_mux(char mode, const char *format, ...)
{
    va_list ap;
    static FILE *tfp;
    if (!tfp) {
        char tfn[16];
        sprintf(tfn, "/tmp/mux.%ctrace", mode);
        tfp = fopen(tfn, "w");
        if (!tfp)
            return;
        setvbuf(tfp, NULL, _IOLBF, 0);
    }
    va_start(ap, format);
    vfprintf(tfp, format, ap);
    va_end(ap);
}

# define TRACE_MUX(args) trace_mux args
#else
# define TRACE_MUX(args) /* nothing */
#endif

/*
 * Fletcher's 16-bit checksum, using 32-bit two's-complement arithmetic.
 */
#define FOLD_ONES_COMPLEMENT_CARRY(X)   ((X) = ((X) & 0xffff) + ((X) >> 16))
#define ONES_COMPLEMENT_ACCUMULATE(X,Y) (X) += (Y); if ((X) & 0x80000000)     \
                                        FOLD_ONES_COMPLEMENT_CARRY(X)
#define FLETCHER_ACCUMULATE(A,B,U)      ONES_COMPLEMENT_ACCUMULATE(A, U);     \
                                        ONES_COMPLEMENT_ACCUMULATE(B, A)

PRUint32
NS_AccumulateFastLoadChecksum(PRUint32 *aChecksum,
                              const PRUint8* aBuffer,
                              PRUint32 aLength,
                              PRBool aLastBuffer)
{
    PRUint32 C = *aChecksum;
    PRUint32 A = C & 0xffff;
    PRUint32 B = C >> 16;

    PRUint16 U = 0;
    if (aLength >= 4) {
        PRBool odd = PRWord(aBuffer) & 1;
        switch (PRWord(aBuffer) & 3) {
          case 3:
            U = (aBuffer[0] << 8) | aBuffer[1];
            FLETCHER_ACCUMULATE(A, B, U);
            U = aBuffer[2];
            aBuffer += 3;
            aLength -= 3;
            break;

          case 2:
            U = (aBuffer[0] << 8) | aBuffer[1];
            FLETCHER_ACCUMULATE(A, B, U);
            U = 0;
            aBuffer += 2;
            aLength -= 2;
            break;

          case 1:
            U = *aBuffer++;
            aLength--;
            break;
        }

        PRUint32 W;
        if (odd) {
            while (aLength > 3) {
                W = *reinterpret_cast<const PRUint32*>(aBuffer);
                U <<= 8;
#ifdef IS_BIG_ENDIAN
                U |= W >> 24;
                FLETCHER_ACCUMULATE(A, B, U);
                U = PRUint16(W >> 8);
                FLETCHER_ACCUMULATE(A, B, U);
                U = W & 0xff;
#else
                U |= W & 0xff;
                FLETCHER_ACCUMULATE(A, B, U);
                U = PRUint16(W >> 8);
                U = NS_SWAP16(U);
                FLETCHER_ACCUMULATE(A, B, U);
                U = W >> 24;
#endif
                aBuffer += 4;
                aLength -= 4;
            }
            aBuffer--;      // we're odd, we didn't checksum the last byte
            aLength++;
        } else {
            while (aLength > 3) {
                W = *reinterpret_cast<const PRUint32*>(aBuffer);
#ifdef IS_BIG_ENDIAN
                U = W >> 16;
                FLETCHER_ACCUMULATE(A, B, U);
                U = PRUint16(W);
                FLETCHER_ACCUMULATE(A, B, U);
#else
                U = NS_SWAP16(W);
                FLETCHER_ACCUMULATE(A, B, U);
                U = W >> 16;
                U = NS_SWAP16(W);
                FLETCHER_ACCUMULATE(A, B, U);
#endif
                aBuffer += 4;
                aLength -= 4;
            }
        }
    }

    if (aLastBuffer) {
        NS_ASSERTION(aLength <= 4, "aLength botch");
        switch (aLength) {
          case 4:
            U = (aBuffer[0] << 8) | aBuffer[1];
            FLETCHER_ACCUMULATE(A, B, U);
            U = (aBuffer[2] << 8) | aBuffer[3];
            FLETCHER_ACCUMULATE(A, B, U);
            break;

          case 3:
            U = (aBuffer[0] << 8) | aBuffer[1];
            FLETCHER_ACCUMULATE(A, B, U);
            U = aBuffer[2];
            FLETCHER_ACCUMULATE(A, B, U);
            break;

          case 2:
            U = (aBuffer[0] << 8) | aBuffer[1];
            FLETCHER_ACCUMULATE(A, B, U);
            break;

          case 1:
            U = aBuffer[0];
            FLETCHER_ACCUMULATE(A, B, U);
            break;
        }

        aLength = 0;
    }

    while (A >> 16)
        FOLD_ONES_COMPLEMENT_CARRY(A);
    while (B >> 16)
        FOLD_ONES_COMPLEMENT_CARRY(B);

    *aChecksum = (B << 16) | A;
    return aLength;
}

PRUint32
NS_AddFastLoadChecksums(PRUint32 sum1, PRUint32 sum2, PRUint32 sum2ByteCount)
{
    PRUint32 A1 = sum1 & 0xffff;
    PRUint32 B1 = sum1 >> 16;

    PRUint32 A2 = sum2 & 0xffff;
    PRUint32 B2 = sum2 >> 16;

    PRUint32 A = A1 + A2;
    while (A >> 16)
        FOLD_ONES_COMPLEMENT_CARRY(A);

    PRUint32 B = B2;
    for (PRUint32 n = (sum2ByteCount + 1) / 2; n != 0; n--)
        ONES_COMPLEMENT_ACCUMULATE(B, B1);
    while (B >> 16)
        FOLD_ONES_COMPLEMENT_CARRY(B);

    return (B << 16) | A;
}

#undef FOLD_ONES_COMPLEMENT_CARRY
#undef ONES_COMPLEMENT_ACCUMULATE
#undef FLETCHER_ACCUMULATE

static const char magic[] = MFL_FILE_MAGIC;

// -------------------------- nsFastLoadFileReader --------------------------

nsID nsFastLoadFileReader::nsFastLoadFooter::gDummyID;
nsFastLoadFileReader::nsObjectMapEntry
    nsFastLoadFileReader::nsFastLoadFooter::gDummySharpObjectEntry;

NS_IMPL_ISUPPORTS_INHERITED5(nsFastLoadFileReader,
                             nsBinaryInputStream,
                             nsIObjectInputStream,
                             nsIFastLoadFileControl,
                             nsIFastLoadReadControl,
                             nsISeekableStream,
                             nsIFastLoadFileReader)

nsresult
nsFastLoadFileReader::ReadHeader(nsFastLoadHeader *aHeader)
{
    nsresult rv;
    PRUint32 bytesRead;

    rv = Read(reinterpret_cast<char*>(aHeader), sizeof *aHeader, &bytesRead);
    if (NS_FAILED(rv))
        return rv;

    if (bytesRead != sizeof *aHeader ||
        memcmp(aHeader->mMagic, magic, MFL_FILE_MAGIC_SIZE)) {
        return NS_ERROR_UNEXPECTED;
    }

    aHeader->mChecksum     = NS_SWAP32(aHeader->mChecksum);
    aHeader->mVersion      = NS_SWAP32(aHeader->mVersion);
    aHeader->mFooterOffset = NS_SWAP32(aHeader->mFooterOffset);
    aHeader->mFileSize     = NS_SWAP32(aHeader->mFileSize);

    return NS_OK;
}

// nsIFastLoadFileControl methods:

NS_IMETHODIMP
nsFastLoadFileReader::GetChecksum(PRUint32 *aChecksum)
{
    *aChecksum = mHeader.mChecksum;
    return NS_OK;
}

struct nsStringMapEntry : public PLDHashEntryHdr {
    const char*     mString;            // key, must come first
    nsISupports*    mURI;               // for SelectMuxedDocument return value
};

struct nsDocumentMapEntry : public nsStringMapEntry {
    PRUint32    mInitialSegmentOffset;  // offset of URI's first segment in file
};

struct nsDocumentMapReadEntry : public nsDocumentMapEntry {
    PRUint32    mNextSegmentOffset;     // offset of URI's next segment to read
    PRUint32    mBytesLeft : 31,        // bytes remaining in current segment
                mNeedToSeek : 1;        // flag to defer Seek from Select to
                                        // Read, in case there is no Read before
                                        // another entry is Selected (to improve
                                        // input stream buffer utilization)
    PRInt64     mSaveOffset;            // in case demux schedule differs from
                                        // mux schedule
};

static void
strmap_ClearEntry(PLDHashTable *aTable, PLDHashEntryHdr *aHdr)
{
    nsStringMapEntry* entry = static_cast<nsStringMapEntry*>(aHdr);

    if (entry->mString)
        nsMemory::Free((void*) entry->mString);
    NS_IF_RELEASE(entry->mURI);
    PL_DHashClearEntryStub(aTable, aHdr);
}

static const PLDHashTableOps strmap_DHashTableOps = {
    PL_DHashAllocTable,
    PL_DHashFreeTable,
    PL_DHashStringKey,
    PL_DHashMatchStringKey,
    PL_DHashMoveEntryStub,
    strmap_ClearEntry,
    PL_DHashFinalizeStub,
    NULL
};

// An nsObjectMapEntry holds a strong reference to an XPCOM object, unless the
// mObject member, when cast to NSFastLoadOID, has its MFL_OBJECT_DEF_TAG bit
// set.  NB: we rely on the fact that an nsISupports* is never an odd pointer.
struct nsObjectMapEntry : public PLDHashEntryHdr {
    nsISupports*            mObject;        // key, must come first
};

// Fast mapping from URI object pointer back to spec-indexed document info.
struct nsURIMapReadEntry : public nsObjectMapEntry {
    nsDocumentMapReadEntry* mDocMapEntry;
};

static void
objmap_ClearEntry(PLDHashTable *aTable, PLDHashEntryHdr *aHdr)
{
    nsObjectMapEntry* entry = static_cast<nsObjectMapEntry*>(aHdr);

    // Ignore tagged object ids stored as object pointer keys (the updater
    // code does this).
    if ((NS_PTR_TO_INT32(entry->mObject) & MFL_OBJECT_DEF_TAG) == 0)
        NS_IF_RELEASE(entry->mObject);
    PL_DHashClearEntryStub(aTable, aHdr);
}

static const PLDHashTableOps objmap_DHashTableOps = {
    PL_DHashAllocTable,
    PL_DHashFreeTable,
    PL_DHashVoidPtrKeyStub,
    PL_DHashMatchEntryStub,
    PL_DHashMoveEntryStub,
    objmap_ClearEntry,
    PL_DHashFinalizeStub,
    NULL
};

NS_IMETHODIMP
nsFastLoadFileReader::HasMuxedDocument(const char* aURISpec, PRBool *aResult)
{
    nsDocumentMapReadEntry* docMapEntry =
        static_cast<nsDocumentMapReadEntry*>
                   (PL_DHashTableOperate(&mFooter.mDocumentMap, aURISpec,
                                         PL_DHASH_LOOKUP));

    *aResult = PL_DHASH_ENTRY_IS_BUSY(docMapEntry);
    return NS_OK;
}

NS_IMETHODIMP
nsFastLoadFileReader::StartMuxedDocument(nsISupports* aURI, const char* aURISpec)
{
    nsDocumentMapReadEntry* docMapEntry =
        static_cast<nsDocumentMapReadEntry*>
                   (PL_DHashTableOperate(&mFooter.mDocumentMap, aURISpec,
                                         PL_DHASH_LOOKUP));

    // If the spec isn't in the map, return NS_ERROR_NOT_AVAILABLE so the
    // FastLoad service can try for a file update.
    if (PL_DHASH_ENTRY_IS_FREE(docMapEntry))
        return NS_ERROR_NOT_AVAILABLE;

    nsCOMPtr<nsISupports> key(do_QueryInterface(aURI));
    nsURIMapReadEntry* uriMapEntry =
        static_cast<nsURIMapReadEntry*>
                   (PL_DHashTableOperate(&mFooter.mURIMap, key,
                                         PL_DHASH_ADD));
    if (!uriMapEntry)
        return NS_ERROR_OUT_OF_MEMORY;

    NS_ASSERTION(uriMapEntry->mDocMapEntry == nsnull,
                 "URI mapped to two different specs?");
    if (uriMapEntry->mDocMapEntry)
        return NS_ERROR_UNEXPECTED;

    docMapEntry->mURI = aURI;
    NS_ADDREF(docMapEntry->mURI);
    uriMapEntry->mObject = key;
    NS_ADDREF(uriMapEntry->mObject);
    uriMapEntry->mDocMapEntry = docMapEntry;
    TRACE_MUX(('r', "start %p (%p) %s\n", aURI, key.get(), aURISpec));
    return NS_OK;
}

NS_IMETHODIMP
nsFastLoadFileReader::SelectMuxedDocument(nsISupports* aURI,
                                          nsISupports** aResult)
{
    nsresult rv;

    // Find the given URI's entry and select it for more reading.
    nsCOMPtr<nsISupports> key(do_QueryInterface(aURI));
    nsURIMapReadEntry* uriMapEntry =
        static_cast<nsURIMapReadEntry*>
                   (PL_DHashTableOperate(&mFooter.mURIMap, key,
                                         PL_DHASH_LOOKUP));

    // If the URI isn't in the map, return NS_ERROR_NOT_AVAILABLE so the
    // FastLoad service can try selecting the file updater.
    if (PL_DHASH_ENTRY_IS_FREE(uriMapEntry))
        return NS_ERROR_NOT_AVAILABLE;

    // If we're interrupting another document's segment, save its offset so
    // we can seek back when it's reselected.  If prevDocMapEntry->mNeedToSeek
    // is set, that means the stream is not positioned for prevDocMapEntry, to
    // avoid buffer thrashing.  See below in this function for more.
    nsDocumentMapReadEntry* prevDocMapEntry = mCurrentDocumentMapEntry;
    if (prevDocMapEntry &&
        prevDocMapEntry->mBytesLeft &&
        !prevDocMapEntry->mNeedToSeek) {
        rv = Tell(&prevDocMapEntry->mSaveOffset);
        if (NS_FAILED(rv))
            return rv;
    }

    // It turns out we get a fair amount of redundant select calls, thanks to
    // non-blocking hunks of data from the parser that are devoid of scripts.
    // As more data gets FastLoaded, the number of these useless selects will
    // decline.
    nsDocumentMapReadEntry* docMapEntry = uriMapEntry->mDocMapEntry;
    if (docMapEntry == prevDocMapEntry) {
        TRACE_MUX(('r', "select prev %s same as current!\n",
                   docMapEntry->mString));
    }

    // Invariant: docMapEntry->mBytesLeft implies docMapEntry->mSaveOffset has
    // been set non-zero by the Tell call above.
    else if (docMapEntry->mBytesLeft) {
        NS_ASSERTION(docMapEntry->mSaveOffset != 0,
                     "reselecting from multiplex at unsaved offset?");

        // Defer Seek till Read, in case of "ping-pong" Selects without any
        // intervening Reads, to avoid dumping the underlying mInputStream's
        // input buffer for cases where alternate "pongs" fall in the same
        // buffer.
        docMapEntry->mNeedToSeek = PR_TRUE;
    }

    *aResult = prevDocMapEntry ? prevDocMapEntry->mURI : nsnull;
    NS_IF_ADDREF(*aResult);

    mCurrentDocumentMapEntry = docMapEntry;
#ifdef DEBUG_MUX
    PRInt64 currentSegmentOffset;
    Tell(&currentSegmentOffset);
    trace_mux('r', "select %p (%p) offset %ld\n",
              aURI, key.get(), (long) currentSegmentOffset);
#endif
    return NS_OK;
}

NS_IMETHODIMP
nsFastLoadFileReader::EndMuxedDocument(nsISupports* aURI)
{
    nsCOMPtr<nsISupports> key(do_QueryInterface(aURI));
    nsURIMapReadEntry* uriMapEntry =
        static_cast<nsURIMapReadEntry*>
                   (PL_DHashTableOperate(&mFooter.mURIMap, key,
                                         PL_DHASH_LOOKUP));

    // If the URI isn't in the map, return NS_ERROR_NOT_AVAILABLE so the
    // FastLoad service can try to end a select on its file updater.
    if (PL_DHASH_ENTRY_IS_FREE(uriMapEntry))
        return NS_ERROR_NOT_AVAILABLE;

    // Drop our ref to the URI object that was passed to StartMuxedDocument,
    // we no longer need it, and we do not want to extend its lifetime.
    if (uriMapEntry->mDocMapEntry)
        NS_RELEASE(uriMapEntry->mDocMapEntry->mURI);

    // Shrink the table if half the entries are removed sentinels.
    PRUint32 size = PL_DHASH_TABLE_SIZE(&mFooter.mURIMap);
    if (mFooter.mURIMap.removedCount >= (size >> 2))
        PL_DHashTableOperate(&mFooter.mURIMap, key, PL_DHASH_REMOVE);
    else
        PL_DHashTableRawRemove(&mFooter.mURIMap, uriMapEntry);

    TRACE_MUX(('r', "end %p (%p)\n", aURI, key.get()));
    return NS_OK;
}

NS_IMETHODIMP
nsFastLoadFileReader::Read(char* aBuffer, PRUint32 aCount, PRUint32 *aBytesRead)
{
    nsDocumentMapReadEntry* entry = mCurrentDocumentMapEntry;
    if (entry) {
        // Don't call our Seek wrapper, as it clears mCurrentDocumentMapEntry.
        if (entry->mNeedToSeek) {
            SeekTo(entry->mSaveOffset);
            entry->mNeedToSeek = PR_FALSE;
        }

        // Loop to handle empty segments, which may be generated by the
        // writer, given Start A; Start B; Select A; Select B; write B data;
        // multiplexing schedules, which do tend to occur given non-blocking
        // i/o with LIFO scheduling.  XXXbe investigate LIFO issues
        while (entry->mBytesLeft == 0) {
            // Check for unexpected end of multiplexed stream.
            NS_ASSERTION(entry->mNextSegmentOffset != 0,
                         "document demuxed from FastLoad file more than once?");
            if (entry->mNextSegmentOffset == 0)
                return NS_ERROR_UNEXPECTED;

            SeekTo(entry->mNextSegmentOffset);
            // Clear mCurrentDocumentMapEntry temporarily to avoid recursion.
            mCurrentDocumentMapEntry = nsnull;

            nsresult rv = Read32(&entry->mNextSegmentOffset);
            if (NS_SUCCEEDED(rv)) {
                PRUint32 bytesLeft = 0;
                rv = Read32(&bytesLeft);
                entry->mBytesLeft = bytesLeft;
            }

            mCurrentDocumentMapEntry = entry;
            if (NS_FAILED(rv))
                return rv;

            NS_ASSERTION(entry->mBytesLeft >= 8, "demux segment length botch!");
            entry->mBytesLeft -= 8;
        }
    }
    if (!mFileData)
        return NS_BASE_STREAM_CLOSED;

    PRUint32 count = PR_MIN(mFileLen - mFilePos, aCount);
    memcpy(aBuffer, mFileData+mFilePos, count);
    *aBytesRead = count;
    mFilePos += count;
    if (entry) {
        NS_ASSERTION(entry->mBytesLeft >= *aBytesRead, "demux Read underflow!");
        entry->mBytesLeft -= *aBytesRead;

#ifdef NS_DEBUG
        // Invariant: !entry->mBytesLeft implies entry->mSaveOffset == 0.
        if (entry->mBytesLeft == 0)
            entry->mSaveOffset = 0;
#endif
    }
    return NS_OK;
}

NS_IMETHODIMP
nsFastLoadFileReader::ReadSegments(nsWriteSegmentFun aWriter, void* aClosure,
                                   PRUint32 aCount, PRUint32 *aResult)
{
    nsDocumentMapReadEntry* entry = mCurrentDocumentMapEntry;

    NS_ASSERTION(!entry || (!entry->mNeedToSeek && entry->mBytesLeft != 0),
                 "ReadSegments called from above nsFastLoadFileReader layer?!");

    if (!mFileData)
        return NS_BASE_STREAM_CLOSED;

    PRUint32 count = PR_MIN(mFileLen - mFilePos, aCount);

    // Errors returned from the writer get ignored.
    aWriter(this, aClosure, (char*)(mFileData + mFilePos), 0,
            count, aResult);
    mFilePos += count;
    if (entry) {
        NS_ASSERTION(entry->mBytesLeft >= *aResult,
                     "demux ReadSegments underflow!");
        entry->mBytesLeft -= *aResult;

#ifdef NS_DEBUG
        // Invariant: !entry->mBytesLeft implies entry->mSaveOffset == 0.
        if (entry->mBytesLeft == 0)
            entry->mSaveOffset = 0;
#endif
    }
    return NS_OK;
}

NS_IMETHODIMP
nsFastLoadFileReader::ComputeChecksum(PRUint32 *aResult)
{
    PRUint32 checksum = 0;
    // Skip first 2 fields.
    PRUint32 pos = offsetof(nsFastLoadHeader, mVersion);
    NS_AccumulateFastLoadChecksum(&checksum,
                                  mFileData + pos,
                                  mFileLen - pos,
                                  PR_TRUE);
    *aResult = checksum;
    return NS_OK;
}

NS_IMETHODIMP
nsFastLoadFileReader::GetDependencies(nsISimpleEnumerator* *aDependencies)
{
    return NS_NewArrayEnumerator(aDependencies, mFooter.mDependencies);
}

nsresult
nsFastLoadFileReader::ReadFooter(nsFastLoadFooter *aFooter)
{
    nsresult rv;

    rv = ReadFooterPrefix(aFooter);
    if (NS_FAILED(rv))
        return rv;

    aFooter->mIDMap = new nsID[aFooter->mNumIDs];
    if (!aFooter->mIDMap)
        return NS_ERROR_OUT_OF_MEMORY;

    PRUint32 i, n;
    for (i = 0, n = aFooter->mNumIDs; i < n; i++) {
        rv = ReadSlowID(&aFooter->mIDMap[i]);
        if (NS_FAILED(rv))
            return rv;
    }

    aFooter->mObjectMap = new nsObjectMapEntry[aFooter->mNumSharpObjects];
    if (!aFooter->mObjectMap)
        return NS_ERROR_OUT_OF_MEMORY;

    for (i = 0, n = aFooter->mNumSharpObjects; i < n; i++) {
        nsObjectMapEntry* entry = &aFooter->mObjectMap[i];

        rv = ReadSharpObjectInfo(entry);
        if (NS_FAILED(rv))
            return rv;

        entry->mReadObject = nsnull;
        entry->mSkipOffset = 0;
        entry->mSaveStrongRefCnt = entry->mStrongRefCnt;
        entry->mSaveWeakRefCnt = entry->mWeakRefCnt;
    }

    if (!PL_DHashTableInit(&aFooter->mDocumentMap, &strmap_DHashTableOps,
                           (void *)this, sizeof(nsDocumentMapReadEntry),
                           aFooter->mNumMuxedDocuments)) {
        aFooter->mDocumentMap.ops = nsnull;
        return NS_ERROR_OUT_OF_MEMORY;
    }

    if (!PL_DHashTableInit(&aFooter->mURIMap, &objmap_DHashTableOps,
                           (void *)this, sizeof(nsURIMapReadEntry),
                           aFooter->mNumMuxedDocuments)) {
        aFooter->mURIMap.ops = nsnull;
        return NS_ERROR_OUT_OF_MEMORY;
    }

    for (i = 0, n = aFooter->mNumMuxedDocuments; i < n; i++) {
        nsFastLoadMuxedDocumentInfo info;

        rv = ReadMuxedDocumentInfo(&info);
        if (NS_FAILED(rv))
            return rv;

        nsDocumentMapReadEntry* entry =
            static_cast<nsDocumentMapReadEntry*>
                       (PL_DHashTableOperate(&aFooter->mDocumentMap,
                                             info.mURISpec,
                                             PL_DHASH_ADD));
        if (!entry) {
            nsMemory::Free((void*) info.mURISpec);
            return NS_ERROR_OUT_OF_MEMORY;
        }

        NS_ASSERTION(!entry->mString, "duplicate URISpec in MuxedDocumentMap");
        entry->mString = info.mURISpec;
        entry->mURI = nsnull;
        entry->mInitialSegmentOffset = info.mInitialSegmentOffset;
        entry->mNextSegmentOffset = info.mInitialSegmentOffset;
        entry->mBytesLeft = 0;
        entry->mNeedToSeek = PR_FALSE;
        entry->mSaveOffset = 0;
    }

    nsCOMPtr<nsISupportsArray> readDeps;
    rv = NS_NewISupportsArray(getter_AddRefs(readDeps));
    if (NS_FAILED(rv))
        return rv;

    nsCAutoString filename;
    for (i = 0, n = aFooter->mNumDependencies; i < n; i++) {
        rv = ReadCString(filename);
        if (NS_FAILED(rv))
            return rv;

        PRInt64 fastLoadMtime;
        rv = Read64(reinterpret_cast<PRUint64*>(&fastLoadMtime));
        if (NS_FAILED(rv))
            return rv;

        nsCOMPtr<nsILocalFile> file;
        rv = NS_NewNativeLocalFile(filename, PR_TRUE, getter_AddRefs(file));
        if (NS_FAILED(rv))
            return rv;
#ifdef DEBUG
        PRInt64 currentMtime;
        rv = file->GetLastModifiedTime(&currentMtime);
        if (NS_FAILED(rv))
            return rv;

        if (LL_NE(fastLoadMtime, currentMtime)) {
            nsCAutoString path;
            file->GetNativePath(path);
            printf("%s mtime changed, invalidating FastLoad file\n",
                   path.get());
            return NS_ERROR_FAILURE;
        }
#endif

        rv = readDeps->AppendElement(file);
        if (NS_FAILED(rv))
            return rv;
    }

    aFooter->mDependencies = readDeps;
    return NS_OK;
}

nsresult
nsFastLoadFileReader::ReadFooterPrefix(nsFastLoadFooterPrefix *aFooterPrefix)
{
    nsresult rv;

    rv = Read32(&aFooterPrefix->mNumIDs);
    if (NS_FAILED(rv))
        return rv;

    rv = Read32(&aFooterPrefix->mNumSharpObjects);
    if (NS_FAILED(rv))
        return rv;

    rv = Read32(&aFooterPrefix->mNumMuxedDocuments);
    if (NS_FAILED(rv))
        return rv;

    rv = Read32(&aFooterPrefix->mNumDependencies);
    if (NS_FAILED(rv))
        return rv;

    return NS_OK;
}

nsresult
nsFastLoadFileReader::ReadSlowID(nsID *aID)
{
    nsresult rv;

    rv = Read32(&aID->m0);
    if (NS_FAILED(rv))
        return rv;

    rv = Read16(&aID->m1);
    if (NS_FAILED(rv))
        return rv;

    rv = Read16(&aID->m2);
    if (NS_FAILED(rv))
        return rv;

    PRUint32 bytesRead;
    rv = Read(reinterpret_cast<char*>(aID->m3), sizeof aID->m3, &bytesRead);
    if (NS_FAILED(rv))
        return rv;

    if (bytesRead != sizeof aID->m3)
        return NS_ERROR_FAILURE;
    return NS_OK;
}

nsresult
nsFastLoadFileReader::ReadFastID(NSFastLoadID *aID)
{
    nsresult rv = Read32(aID);
    if (NS_SUCCEEDED(rv))
        *aID ^= MFL_ID_XOR_KEY;
    return rv;
}

nsresult
nsFastLoadFileReader::ReadSharpObjectInfo(nsFastLoadSharpObjectInfo *aInfo)
{
    nsresult rv;

    rv = Read32(&aInfo->mCIDOffset);
    if (NS_FAILED(rv))
        return rv;

    NS_ASSERTION(aInfo->mCIDOffset != 0,
                 "fastload reader: mCIDOffset cannot be zero!");

    rv = Read16(&aInfo->mStrongRefCnt);
    if (NS_FAILED(rv))
        return rv;

    rv = Read16(&aInfo->mWeakRefCnt);
    if (NS_FAILED(rv))
        return rv;

    return NS_OK;
}

nsresult
nsFastLoadFileReader::ReadMuxedDocumentInfo(nsFastLoadMuxedDocumentInfo *aInfo)
{
    nsresult rv;

    nsCAutoString spec;
    rv = ReadCString(spec);
    if (NS_FAILED(rv))
        return rv;

    rv = Read32(&aInfo->mInitialSegmentOffset);
    if (NS_FAILED(rv))
        return rv;

    aInfo->mURISpec = ToNewCString(spec);
    return NS_OK;
}

nsresult
nsFastLoadFileReader::Open()
{
    nsresult rv;
    nsCOMPtr<nsILocalFile> localFile = do_QueryInterface(mFile, &rv);
    if (NS_FAILED(rv))
        return rv;
    PRFileDesc *fd;    // OS file-descriptor
    rv = localFile->OpenNSPRFileDesc(PR_RDONLY, 0, &fd);
    if (NS_FAILED(rv))
        return rv;

    PRInt64 size = PR_Available64(fd);
    if (size >= PR_INT32_MAX) {
        PR_Close(fd);
        return NS_ERROR_FILE_TOO_BIG;
    }

    mFileLen = (PRUint32) size;
    if (mFileLen < sizeof(nsFastLoadHeader)) {
        PR_Close(fd);
        return NS_ERROR_FAILURE;
    }

    mFileMap = PR_CreateFileMap(fd, mFileLen, PR_PROT_READONLY);
    if (!mFileMap) {
        PR_Close(fd);
        return NS_ERROR_FAILURE;
    }

    mFileData = (PRUint8*) PR_MemMap(mFileMap, 0, mFileLen);
    // At this point the non-mmap file descriptor is no longer needed
    PR_Close(fd);

    if (!mFileData)
        return NS_ERROR_FAILURE;

#if defined(XP_UNIX)
    madvise((char *)mFileData, mFileLen, MADV_WILLNEED);
#endif

    rv = ReadHeader(&mHeader);
    if (NS_FAILED(rv))
        return rv;

    PRUint32 checksum;
    rv = ComputeChecksum(&checksum);
    if (NS_FAILED(rv))
        return rv;
    
    if (checksum != mHeader.mChecksum)
        return NS_ERROR_FAILURE;

    if (mHeader.mVersion != MFL_FILE_VERSION ||
        mHeader.mFooterOffset == 0 || 
        memcmp(mHeader.mMagic, magic, MFL_FILE_MAGIC_SIZE))
        return NS_ERROR_UNEXPECTED;
    
    SeekTo(mHeader.mFooterOffset);

    rv = ReadFooter(&mFooter);
    if (NS_FAILED(rv))
        return rv;

    SeekTo(sizeof(nsFastLoadHeader));
    return NS_OK;
}

NS_IMETHODIMP
nsFastLoadFileReader::Close()
{
    // Give up our strong "keepalive" references, in case not all objects that
    // were deserialized were fully re-connected.
    //
    // This happens for sure when an nsFastLoadFileUpdater is created and wraps
    // an nsFastLoadFileReader whose data was already deserialized by an earlier
    // FastLoad episode.  The reader is useful in the second such episode during
    // a session not so much for reading objects as for its footer information,
    // which primes the updater's tables so that after the update completes, the
    // FastLoad file has a superset footer.
    if (mFileData) {
        PR_MemUnmap(mFileData, mFileLen);
        mFileData = nsnull;
    }

    if (mFileMap) {
        PR_CloseFileMap(mFileMap);
        mFileMap = nsnull;
    }

    mFileLen = 0;
    mFilePos = 0;
    
    if (!mFooter.mObjectMap)
        return NS_OK;

    for (PRUint32 i = 0, n = mFooter.mNumSharpObjects; i < n; i++) {
        nsObjectMapEntry* entry = &mFooter.mObjectMap[i];
        entry->mReadObject = nsnull;
    }
    mFooter.mNumSharpObjects = 0;

    return NS_OK;
}

nsresult
nsFastLoadFileReader::DeserializeObject(nsISupports* *aObject)
{
    nsresult rv;
    NSFastLoadID fastCID;

    rv = ReadFastID(&fastCID);
    if (NS_FAILED(rv))
        return rv;

    const nsID& slowCID = mFooter.GetID(fastCID);
    nsCOMPtr<nsISupports> object(do_CreateInstance(slowCID, &rv));
    if (NS_FAILED(rv))
        return rv;

    nsCOMPtr<nsISerializable> serializable(do_QueryInterface(object));
    if (!serializable)
        return NS_ERROR_FAILURE;

    rv = serializable->Read(this);
    if (NS_FAILED(rv))
        return rv;

    *aObject = object;
    NS_ADDREF(*aObject);
    return NS_OK;
}

nsresult
nsFastLoadFileReader::ReadObject(PRBool aIsStrongRef, nsISupports* *aObject)
{
    nsresult rv;
    NSFastLoadOID oid;

    rv = Read32(&oid);
    if (NS_FAILED(rv))
        return rv;
    oid ^= MFL_OID_XOR_KEY;

    nsCOMPtr<nsISupports> object;

    if (oid == MFL_DULL_OBJECT_OID) {
        // A very dull object, defined at point of single (strong) reference.
        NS_ASSERTION(aIsStrongRef, "dull object read via weak ref!");

        rv = DeserializeObject(getter_AddRefs(object));
        if (NS_FAILED(rv))
            return rv;
    } else {
        NS_ASSERTION((oid & MFL_WEAK_REF_TAG) ==
                     (aIsStrongRef ? 0 : MFL_WEAK_REF_TAG),
                     "strong vs. weak ref deserialization mismatch!");

        nsObjectMapEntry* entry = &mFooter.GetSharpObjectEntry(oid);

        // Check whether we've already deserialized the object for this OID.
        object = entry->mReadObject;
        if (!object) {
            nsDocumentMapReadEntry* saveDocMapEntry = nsnull;

            PRUint32 saveOffset32 = mFilePos;
            if (entry->mCIDOffset != saveOffset32) {
                // We skipped deserialization of this object from its position
                // earlier in the input stream, presumably due to the reference
                // there being an nsFastLoadPtr, or (more likely) because the
                // object was muxed in another document, and deserialization
                // order does not match serialization order.  So we must seek
                // back and read it now.
                NS_ASSERTION(entry->mCIDOffset < saveOffset32,
                             "out of order object?!");

                // Ape our Seek wrapper by clearing mCurrentDocumentMapEntry.
                // This allows for a skipped object to be referenced from two
                // or more multiplexed documents in the FastLoad file.
                saveDocMapEntry = mCurrentDocumentMapEntry;
                mCurrentDocumentMapEntry = nsnull;
                SeekTo(entry->mCIDOffset);
            }

            rv = DeserializeObject(getter_AddRefs(object));
            if (NS_FAILED(rv))
                return rv;

            if (entry->mCIDOffset != saveOffset32) {
                // Save the "skip offset" in case we need to skip this object
                // definition when reading forward, later on.
                entry->mSkipOffset = mFilePos;
                // Restore stream offset and mCurrentDocumentMapEntry in case
                // we're still reading forward through a part of the multiplex
                // to get object definitions eagerly.
                SeekTo(saveOffset32);
                mCurrentDocumentMapEntry = saveDocMapEntry;
            }

            // Save object until all refs have been deserialized.
            entry->mReadObject = object;
        } else {
            // What if we are at a definition that's already been read?  This
            // case arises when a sharp object's def is serialized before its
            // refs, while a non-defining ref is deserialized before the def.
            // We must skip over the object definition.
            if (oid & MFL_OBJECT_DEF_TAG) {
                NS_ASSERTION(entry->mSkipOffset != 0, "impossible! see above");

                // Since we are seeking within a muxed segment, we must adjust
                // mBytesLeft, so that Seek called from Read will be triggered
                // when mBytesLeft goes to zero.
                PRUint32 currentOffset = mFilePos;
                NS_ASSERTION(entry->mSkipOffset > (PRUint32)currentOffset,
                             "skipping backwards from object?!");
                NS_ASSERTION(mCurrentDocumentMapEntry->mBytesLeft >=
                             entry->mSkipOffset - (PRUint32)currentOffset,
                             "skipped object buffer underflow!");

                mCurrentDocumentMapEntry->mBytesLeft -=
                    entry->mSkipOffset - (PRUint32)currentOffset;

                SeekTo(entry->mSkipOffset);
            }
        }

        if (aIsStrongRef) {
            NS_ASSERTION(entry->mStrongRefCnt != 0,
                         "mStrongRefCnt underflow!");
            --entry->mStrongRefCnt;
        } else {
            NS_ASSERTION(MFL_GET_WEAK_REFCNT(entry) != 0,
                         "mWeakRefCnt underflow!");
            MFL_DROP_WEAK_REFCNT(entry);
        }

        if (entry->mStrongRefCnt == 0 && MFL_GET_WEAK_REFCNT(entry) == 0)
            entry->mReadObject = nsnull;
    }

    if (oid & MFL_QUERY_INTERFACE_TAG) {
        NSFastLoadID iid;
        rv = ReadFastID(&iid);
        if (NS_FAILED(rv))
            return rv;

        rv = object->QueryInterface(mFooter.GetID(iid),
                                    reinterpret_cast<void**>(aObject));
        if (NS_FAILED(rv))
            return rv;
    } else {
        *aObject = object;
        NS_ADDREF(*aObject);
    }

    return NS_OK;
}

NS_IMETHODIMP
nsFastLoadFileReader::ReadID(nsID *aResult)
{
    nsresult rv;
    NSFastLoadID fastID;

    rv = ReadFastID(&fastID);
    if (NS_FAILED(rv))
        return rv;

    *aResult = mFooter.GetID(fastID);
    return NS_OK;
}

NS_IMETHODIMP
nsFastLoadFileReader::Seek(PRInt32 aWhence, PRInt64 aOffset)
{
    NS_ASSERTION(aWhence == nsISeekableStream::NS_SEEK_SET, "Only NS_SEEK_SET seeks are supported");
    mCurrentDocumentMapEntry = nsnull;
    SeekTo(aOffset);
    return NS_OK;
}

NS_IMETHODIMP
nsFastLoadFileReader::Tell(PRInt64 *aResult)
{
    *aResult = mFilePos;
    return NS_OK;
}

NS_IMETHODIMP
nsFastLoadFileReader::SetEOF()
{
    NS_ERROR("Refusing to truncate a memory-mapped file");
    return NS_ERROR_NOT_IMPLEMENTED;
}

NS_COM nsresult
NS_NewFastLoadFileReader(nsIObjectInputStream* *aResult, nsIFile *aFile)
{
    nsFastLoadFileReader* reader = new nsFastLoadFileReader(aFile);
    if (!reader)
        return NS_ERROR_OUT_OF_MEMORY;

    // Stabilize reader's refcnt.
    nsCOMPtr<nsIObjectInputStream> stream(reader);

    nsresult rv = reader->Open();
    if (NS_FAILED(rv))
        return rv;

    *aResult = stream;
    NS_ADDREF(*aResult);
    return NS_OK;
}

// -------------------------- nsFastLoadFileWriter --------------------------

NS_IMPL_ISUPPORTS_INHERITED4(nsFastLoadFileWriter,
                             nsBinaryOutputStream,
                             nsIObjectOutputStream,
                             nsIFastLoadFileControl,
                             nsIFastLoadWriteControl,
                             nsISeekableStream)

struct nsIDMapEntry : public PLDHashEntryHdr {
    NSFastLoadID    mFastID;            // 1 + nsFastLoadFooter::mIDMap index
    nsID            mSlowID;            // key, used by PLDHashTableOps below
};

static PLDHashNumber
idmap_HashKey(PLDHashTable *aTable, const void *aKey)
{
    const nsID *idp = reinterpret_cast<const nsID*>(aKey);

    return idp->m0;
}

static PRBool
idmap_MatchEntry(PLDHashTable *aTable,
                const PLDHashEntryHdr *aHdr,
                const void *aKey)
{
    const nsIDMapEntry* entry = static_cast<const nsIDMapEntry*>(aHdr);
    const nsID *idp = reinterpret_cast<const nsID*>(aKey);

    return memcmp(&entry->mSlowID, idp, sizeof(nsID)) == 0;
}

static const PLDHashTableOps idmap_DHashTableOps = {
    PL_DHashAllocTable,
    PL_DHashFreeTable,
    idmap_HashKey,
    idmap_MatchEntry,
    PL_DHashMoveEntryStub,
    PL_DHashClearEntryStub,
    PL_DHashFinalizeStub,
    NULL
};

nsresult
nsFastLoadFileWriter::MapID(const nsID& aSlowID, NSFastLoadID *aResult)
{
    nsIDMapEntry* entry =
        static_cast<nsIDMapEntry*>
                   (PL_DHashTableOperate(&mIDMap, &aSlowID, PL_DHASH_ADD));
    if (!entry)
        return NS_ERROR_OUT_OF_MEMORY;

    if (entry->mFastID == 0) {
        entry->mFastID = mIDMap.entryCount;
        entry->mSlowID = aSlowID;
    }

    *aResult = entry->mFastID;
    return NS_OK;
}

nsresult
nsFastLoadFileWriter::WriteHeader(nsFastLoadHeader *aHeader)
{
    nsresult rv;
    PRUint32 bytesWritten;

    rv = Write(aHeader->mMagic, MFL_FILE_MAGIC_SIZE, &bytesWritten);
    if (NS_FAILED(rv))
        return rv;

    if (bytesWritten != MFL_FILE_MAGIC_SIZE)
        return NS_ERROR_FAILURE;

    rv = Write32(aHeader->mChecksum);
    if (NS_FAILED(rv))
        return rv;

    rv = Write32(aHeader->mVersion);
    if (NS_FAILED(rv))
        return rv;

    rv = Write32(aHeader->mFooterOffset);
    if (NS_FAILED(rv))
        return rv;

    rv = Write32(aHeader->mFileSize);
    if (NS_FAILED(rv))
        return rv;

    return NS_OK;
}

// nsIFastLoadFileControl methods:

NS_IMETHODIMP
nsFastLoadFileWriter::GetChecksum(PRUint32 *aChecksum)
{
    if (mHeader.mChecksum == 0)
        return NS_ERROR_NOT_AVAILABLE;
    *aChecksum = mHeader.mChecksum;
    return NS_OK;
}

struct nsDocumentMapWriteEntry : public nsDocumentMapEntry {
    PRUint32    mCurrentSegmentOffset;      // last written segment's offset
};

// Fast mapping from URI object pointer back to spec-indexed document info.
// We also may need the slow mapping from mURISpec to nsDocumentMapWriteEntry,
// because the writer's mDocumentMap double hash table may grow "behind the
// back of" each mURIMap entry's mDocMapEntry member.
struct nsURIMapWriteEntry : public nsObjectMapEntry {
    nsDocumentMapWriteEntry* mDocMapEntry;
    PRUint32                 mGeneration;
    const char*              mURISpec;
};

NS_IMETHODIMP
nsFastLoadFileWriter::HasMuxedDocument(const char* aURISpec, PRBool *aResult)
{
    nsDocumentMapWriteEntry* docMapEntry =
        static_cast<nsDocumentMapWriteEntry*>
                   (PL_DHashTableOperate(&mDocumentMap, aURISpec,
                                         PL_DHASH_LOOKUP));

    *aResult = PL_DHASH_ENTRY_IS_BUSY(docMapEntry);
    return NS_OK;
}

NS_IMETHODIMP
nsFastLoadFileWriter::StartMuxedDocument(nsISupports* aURI,
                                         const char* aURISpec)
{
    // Save mDocumentMap table generation and mCurrentDocumentMapEntry key in
    // case the hash table grows during the PL_DHASH_ADD operation.
    PRUint32 saveGeneration = mDocumentMap.generation;
    const char* saveURISpec = mCurrentDocumentMapEntry
                              ? mCurrentDocumentMapEntry->mString
                              : nsnull;

    nsDocumentMapWriteEntry* docMapEntry =
        static_cast<nsDocumentMapWriteEntry*>
                   (PL_DHashTableOperate(&mDocumentMap, aURISpec,
                                         PL_DHASH_ADD));
    if (!docMapEntry)
        return NS_ERROR_OUT_OF_MEMORY;

    // If the generation number changed, refresh mCurrentDocumentMapEntry.
    if (mCurrentDocumentMapEntry && mDocumentMap.generation != saveGeneration) {
        mCurrentDocumentMapEntry =
            static_cast<nsDocumentMapWriteEntry*>
                       (PL_DHashTableOperate(&mDocumentMap, saveURISpec,
                                             PL_DHASH_LOOKUP));
        NS_ASSERTION(PL_DHASH_ENTRY_IS_BUSY(mCurrentDocumentMapEntry),
                     "mCurrentDocumentMapEntry lost during table growth?!");

        // Refresh saveGeneration for use below when initializing uriMapEntry.
        saveGeneration = mDocumentMap.generation;
    }

    NS_WARN_IF_FALSE(docMapEntry->mString == nsnull,
                     "redundant multiplexed document?");
    if (docMapEntry->mString)
        return NS_ERROR_UNEXPECTED;

    void* spec = nsMemory::Clone(aURISpec, strlen(aURISpec) + 1);
    if (!spec)
        return NS_ERROR_OUT_OF_MEMORY;
    docMapEntry->mString = reinterpret_cast<const char*>(spec);
    docMapEntry->mURI = aURI;
    NS_ADDREF(docMapEntry->mURI);

    nsCOMPtr<nsISupports> key(do_QueryInterface(aURI));
    nsURIMapWriteEntry* uriMapEntry =
        static_cast<nsURIMapWriteEntry*>
                   (PL_DHashTableOperate(&mURIMap, key, PL_DHASH_ADD));
    if (!uriMapEntry)
        return NS_ERROR_OUT_OF_MEMORY;

    NS_ASSERTION(uriMapEntry->mDocMapEntry == nsnull,
                 "URI mapped to two different specs?");
    if (uriMapEntry->mDocMapEntry)
        return NS_ERROR_UNEXPECTED;

    uriMapEntry->mObject = key;
    NS_ADDREF(uriMapEntry->mObject);
    uriMapEntry->mDocMapEntry = docMapEntry;
    uriMapEntry->mGeneration = saveGeneration;
    uriMapEntry->mURISpec = reinterpret_cast<const char*>(spec);
    TRACE_MUX(('w', "start %p (%p) %s\n", aURI, key.get(), aURISpec));
    return NS_OK;
}

NS_IMETHODIMP
nsFastLoadFileWriter::SelectMuxedDocument(nsISupports* aURI,
                                          nsISupports** aResult)
{
    // Capture the current file offset (XXXbe maintain our own via Write?)
    nsresult rv;
    PRInt64 currentSegmentOffset;
    rv = mSeekableOutput->Tell(&currentSegmentOffset);
    if (NS_FAILED(rv))
        return rv;

    PRUint32 currentSegmentOffset32 = currentSegmentOffset;
    // Look for an existing entry keyed by aURI, added by StartMuxedDocument.
    nsCOMPtr<nsISupports> key(do_QueryInterface(aURI));
    nsURIMapWriteEntry* uriMapEntry =
        static_cast<nsURIMapWriteEntry*>
                   (PL_DHashTableOperate(&mURIMap, key, PL_DHASH_LOOKUP));
    NS_ASSERTION(PL_DHASH_ENTRY_IS_BUSY(uriMapEntry),
                 "SelectMuxedDocument without prior StartMuxedDocument?");
    if (PL_DHASH_ENTRY_IS_FREE(uriMapEntry))
        return NS_ERROR_UNEXPECTED;

    // Beware that uriMapEntry->mDocMapEntry may be stale, if an mDocumentMap
    // addition caused that table to grow.  We save the mDocumentMap generation
    // in each uriMapEntry and compare it to the current generation, rehashing
    // uriMapEntry->mURISpec if necessary.

    nsDocumentMapWriteEntry* docMapEntry = uriMapEntry->mDocMapEntry;
    if (uriMapEntry->mGeneration != mDocumentMap.generation) {
        docMapEntry =
            static_cast<nsDocumentMapWriteEntry*>
                       (PL_DHashTableOperate(&mDocumentMap,
                                             uriMapEntry->mURISpec,
                                             PL_DHASH_LOOKUP));
        NS_ASSERTION(PL_DHASH_ENTRY_IS_BUSY(docMapEntry), "lost mDocMapEntry!?");
        uriMapEntry->mDocMapEntry = docMapEntry;
        uriMapEntry->mGeneration = mDocumentMap.generation;
    }

    // If there is a muxed document segment open, close it now by setting its
    // length, stored in the second PRUint32 of the segment.
    nsDocumentMapWriteEntry* prevDocMapEntry = mCurrentDocumentMapEntry;
    if (prevDocMapEntry) {
        if (prevDocMapEntry == docMapEntry) {
            TRACE_MUX(('w', "select prev %s same as current!\n",
                       prevDocMapEntry->mString));
            *aResult = docMapEntry->mURI;
            NS_ADDREF(*aResult);
            return NS_OK;
        }

        PRUint32 prevSegmentOffset = prevDocMapEntry->mCurrentSegmentOffset;
        TRACE_MUX(('w', "select prev %s offset %lu\n",
                   prevDocMapEntry->mString, prevSegmentOffset));

        rv = mSeekableOutput->Seek(nsISeekableStream::NS_SEEK_SET,
                                   prevSegmentOffset + 4);
        if (NS_FAILED(rv))
            return rv;

        // The length counts all bytes in the segment, including the header
        // that contains [nextSegmentOffset, length].
        rv = Write32(currentSegmentOffset32 - prevSegmentOffset);
        if (NS_FAILED(rv))
            return rv;

        // Seek back to the current offset only if we are not going to seek
        // back to *this* entry's last "current" segment offset and write its
        // next segment offset at the first PRUint32 of the segment.
        if (!docMapEntry->mInitialSegmentOffset) {
            rv = mSeekableOutput->Seek(nsISeekableStream::NS_SEEK_SET,
                                       currentSegmentOffset);
            if (NS_FAILED(rv))
                return rv;
        }
    }

    // If this entry was newly added, set its key and initial segment offset.
    // Otherwise, seek back to write the next segment offset of the previous
    // segment for this document in the multiplex.
    if (!docMapEntry->mInitialSegmentOffset) {
        docMapEntry->mInitialSegmentOffset = currentSegmentOffset32;
    } else {
        rv = mSeekableOutput->Seek(nsISeekableStream::NS_SEEK_SET,
                                   docMapEntry->mCurrentSegmentOffset);
        if (NS_FAILED(rv))
            return rv;

        rv = Write32(currentSegmentOffset32);
        if (NS_FAILED(rv))
            return rv;

        rv = mSeekableOutput->Seek(nsISeekableStream::NS_SEEK_SET,
                                   currentSegmentOffset);
        if (NS_FAILED(rv))
            return rv;
    }

    // Update this document's current segment offset so we can later fix its
    // next segment offset (unless it is last, in which case we leave the zero
    // placeholder as a terminator).
    docMapEntry->mCurrentSegmentOffset = currentSegmentOffset32;

    rv = Write32(0);    // nextSegmentOffset placeholder
    if (NS_FAILED(rv))
        return rv;

    rv = Write32(0);    // length placeholder
    if (NS_FAILED(rv))
        return rv;

    *aResult = prevDocMapEntry ? prevDocMapEntry->mURI : nsnull;
    NS_IF_ADDREF(*aResult);

    mCurrentDocumentMapEntry = docMapEntry;
    TRACE_MUX(('w', "select %p (%p) offset %lu\n",
               aURI, key.get(), currentSegmentOffset));
    return NS_OK;
}

NS_IMETHODIMP
nsFastLoadFileWriter::EndMuxedDocument(nsISupports* aURI)
{
    nsCOMPtr<nsISupports> key(do_QueryInterface(aURI));
    nsURIMapWriteEntry* uriMapEntry =
        static_cast<nsURIMapWriteEntry*>
                   (PL_DHashTableOperate(&mURIMap, key, PL_DHASH_LOOKUP));

    // If the URI isn't in the map, nsFastLoadFileWriter::StartMuxedDocument
    // must have been called with a redundant URI, *and* its caller must have
    // ignored the NS_ERROR_UNEXPECTED it returned in that case.
    if (PL_DHASH_ENTRY_IS_FREE(uriMapEntry)) {
        TRACE_MUX(('w', "bad end %p (%p)\n", aURI, key.get()));
        return NS_ERROR_UNEXPECTED;
    }

    // Drop our ref to the URI object that was passed to StartMuxedDocument,
    // we no longer need it, and we do not want to extend its lifetime.
    if (uriMapEntry->mDocMapEntry)
        NS_RELEASE(uriMapEntry->mDocMapEntry->mURI);

    // Shrink the table if half the entries are removed sentinels.
    PRUint32 size = PL_DHASH_TABLE_SIZE(&mURIMap);
    if (mURIMap.removedCount >= (size >> 2))
        PL_DHashTableOperate(&mURIMap, key, PL_DHASH_REMOVE);
    else
        PL_DHashTableRawRemove(&mURIMap, uriMapEntry);

    TRACE_MUX(('w', "end %p (%p)\n", aURI, key.get()));
    return NS_OK;
}

struct nsDependencyMapEntry : public nsStringMapEntry {
    PRInt64 mLastModified;
};

NS_IMETHODIMP
nsFastLoadFileWriter::AddDependency(nsIFile* aFile)
{
    nsCAutoString path;
    nsresult rv = aFile->GetNativePath(path);
    if (NS_FAILED(rv))
        return rv;

    nsDependencyMapEntry* entry =
        static_cast<nsDependencyMapEntry*>
                   (PL_DHashTableOperate(&mDependencyMap, path.get(),
                                         PL_DHASH_ADD));
    if (!entry)
        return NS_ERROR_OUT_OF_MEMORY;

    if (!entry->mString) {
        const char *tmp = ToNewCString(path);
        if (!tmp)
            return NS_ERROR_OUT_OF_MEMORY;
        entry->mString = tmp;

        // If we can't get the last modified time from aFile, assume it does
        // not exist, or is otherwise inaccessible to us (due to permissions),
        // remove the dependency, and suppress the failure.
        //
        // Otherwise, we would end up aborting the fastload process due to a
        // missing .js or .xul or other file on every startup.

        rv = aFile->GetLastModifiedTime(&entry->mLastModified);
        if (NS_FAILED(rv)) {
            PL_DHashTableOperate(&mDependencyMap, path.get(), PL_DHASH_REMOVE);
            rv = NS_OK;
        }
    }
    return rv;
}

nsresult
nsFastLoadFileWriter::WriteFooterPrefix(const nsFastLoadFooterPrefix& aFooterPrefix)
{
    nsresult rv;

    rv = Write32(aFooterPrefix.mNumIDs);
    if (NS_FAILED(rv))
        return rv;

    rv = Write32(aFooterPrefix.mNumSharpObjects);
    if (NS_FAILED(rv))
        return rv;

    rv = Write32(aFooterPrefix.mNumMuxedDocuments);
    if (NS_FAILED(rv))
        return rv;

    rv = Write32(aFooterPrefix.mNumDependencies);
    if (NS_FAILED(rv))
        return rv;

    return NS_OK;
}

nsresult
nsFastLoadFileWriter::WriteSlowID(const nsID& aID)
{
    nsresult rv;

    rv = Write32(aID.m0);
    if (NS_FAILED(rv))
        return rv;

    rv = Write16(aID.m1);
    if (NS_FAILED(rv))
        return rv;

    rv = Write16(aID.m2);
    if (NS_FAILED(rv))
        return rv;

    PRUint32 bytesWritten;
    rv = Write(reinterpret_cast<const char*>(aID.m3), sizeof aID.m3,
               &bytesWritten);
    if (NS_FAILED(rv))
        return rv;

    if (bytesWritten != sizeof aID.m3)
        return NS_ERROR_FAILURE;
    return NS_OK;
}

nsresult
nsFastLoadFileWriter::WriteFastID(NSFastLoadID aID)
{
    return Write32(aID ^ MFL_ID_XOR_KEY);
}

nsresult
nsFastLoadFileWriter::WriteSharpObjectInfo(const nsFastLoadSharpObjectInfo& aInfo)
{
    nsresult rv;

    NS_ASSERTION(aInfo.mCIDOffset != 0,
                 "fastload writer: mCIDOffset cannot be zero!");

    rv = Write32(aInfo.mCIDOffset);
    if (NS_FAILED(rv))
        return rv;

    rv = Write16(aInfo.mStrongRefCnt);
    if (NS_FAILED(rv))
        return rv;

    rv = Write16(aInfo.mWeakRefCnt);
    if (NS_FAILED(rv))
        return rv;

    return NS_OK;
}

nsresult
nsFastLoadFileWriter::WriteMuxedDocumentInfo(const nsFastLoadMuxedDocumentInfo& aInfo)
{
    nsresult rv;

    rv = WriteStringZ(aInfo.mURISpec);
    if (NS_FAILED(rv))
        return rv;

    rv = Write32(aInfo.mInitialSegmentOffset);
    if (NS_FAILED(rv))
        return rv;

    return NS_OK;
}

PLDHashOperator
nsFastLoadFileWriter::IDMapEnumerate(PLDHashTable *aTable,
                                     PLDHashEntryHdr *aHdr,
                                     PRUint32 aNumber,
                                     void *aData)
{
    nsIDMapEntry* entry = static_cast<nsIDMapEntry*>(aHdr);
    PRUint32 index = entry->mFastID - 1;
    nsID* vector = reinterpret_cast<nsID*>(aData);

    NS_ASSERTION(index < aTable->entryCount, "bad nsIDMap index!");
    vector[index] = entry->mSlowID;
    return PL_DHASH_NEXT;
}

struct nsSharpObjectMapEntry : public nsObjectMapEntry {
    NSFastLoadOID               mOID;
    nsFastLoadSharpObjectInfo   mInfo;
};

PLDHashOperator
nsFastLoadFileWriter::ObjectMapEnumerate(PLDHashTable *aTable,
                                         PLDHashEntryHdr *aHdr,
                                         PRUint32 aNumber,
                                         void *aData)
{
    nsSharpObjectMapEntry* entry = static_cast<nsSharpObjectMapEntry*>(aHdr);
    PRUint32 index = MFL_OID_TO_SHARP_INDEX(entry->mOID);
    nsFastLoadSharpObjectInfo* vector =
        reinterpret_cast<nsFastLoadSharpObjectInfo*>(aData);

    NS_ASSERTION(index < aTable->entryCount, "bad nsObjectMap index!");
    vector[index] = entry->mInfo;

    NS_ASSERTION(entry->mInfo.mStrongRefCnt, "no strong ref in serialization!");

    // Ignore tagged object ids stored as object pointer keys (the updater
    // code does this).
    if ((NS_PTR_TO_INT32(entry->mObject) & MFL_OBJECT_DEF_TAG) == 0)
        NS_RELEASE(entry->mObject);

    return PL_DHASH_NEXT;
}

PLDHashOperator
nsFastLoadFileWriter::DocumentMapEnumerate(PLDHashTable *aTable,
                                           PLDHashEntryHdr *aHdr,
                                           PRUint32 aNumber,
                                           void *aData)
{
    nsFastLoadFileWriter* writer =
        reinterpret_cast<nsFastLoadFileWriter*>(aTable->data);
    nsDocumentMapWriteEntry* entry =
        static_cast<nsDocumentMapWriteEntry*>(aHdr);
    nsresult* rvp = reinterpret_cast<nsresult*>(aData);

    nsFastLoadMuxedDocumentInfo info;
    info.mURISpec = entry->mString;
    info.mInitialSegmentOffset = entry->mInitialSegmentOffset;
    *rvp = writer->WriteMuxedDocumentInfo(info);

    return NS_FAILED(*rvp) ? PL_DHASH_STOP : PL_DHASH_NEXT;
}

PLDHashOperator
nsFastLoadFileWriter::DependencyMapEnumerate(PLDHashTable *aTable,
                                             PLDHashEntryHdr *aHdr,
                                             PRUint32 aNumber,
                                             void *aData)
{
    nsFastLoadFileWriter* writer =
        reinterpret_cast<nsFastLoadFileWriter*>(aTable->data);
    nsDependencyMapEntry* entry = static_cast<nsDependencyMapEntry*>(aHdr);
    nsresult* rvp = reinterpret_cast<nsresult*>(aData);

    *rvp = writer->WriteStringZ(entry->mString);
    if (NS_SUCCEEDED(*rvp))
        *rvp = writer->Write64(entry->mLastModified);

    return NS_FAILED(*rvp) ? PL_DHASH_STOP :PL_DHASH_NEXT;
}

nsresult
nsFastLoadFileWriter::WriteFooter()
{
    nsresult rv;
    PRUint32 i, count;

    nsFastLoadFooterPrefix footerPrefix;
    footerPrefix.mNumIDs = mIDMap.entryCount;
    footerPrefix.mNumSharpObjects = mObjectMap.entryCount;
    footerPrefix.mNumMuxedDocuments = mDocumentMap.entryCount;
    footerPrefix.mNumDependencies = mDependencyMap.entryCount;

    rv = WriteFooterPrefix(footerPrefix);
    if (NS_FAILED(rv))
        return rv;

    // Enumerate mIDMap into a vector indexed by mFastID and write it.
    nsID* idvec = new nsID[footerPrefix.mNumIDs];
    if (!idvec)
        return NS_ERROR_OUT_OF_MEMORY;

    count = PL_DHashTableEnumerate(&mIDMap, IDMapEnumerate, idvec);
    NS_ASSERTION(count == footerPrefix.mNumIDs, "bad mIDMap enumeration!");
    for (i = 0; i < count; i++) {
        rv = WriteSlowID(idvec[i]);
        if (NS_FAILED(rv)) break;
    }

    delete[] idvec;
    if (NS_FAILED(rv))
        return rv;

    // Enumerate mObjectMap into a vector indexed by mOID and write it.
    nsFastLoadSharpObjectInfo* objvec =
        new nsFastLoadSharpObjectInfo[footerPrefix.mNumSharpObjects];
    if (!objvec)
        return NS_ERROR_OUT_OF_MEMORY;
#ifdef NS_DEBUG
    memset(objvec, 0, footerPrefix.mNumSharpObjects *
                      sizeof(nsFastLoadSharpObjectInfo));
#endif

    count = PL_DHashTableEnumerate(&mObjectMap, ObjectMapEnumerate, objvec);
    NS_ASSERTION(count == footerPrefix.mNumSharpObjects,
                 "bad mObjectMap enumeration!");
    for (i = 0; i < count; i++) {
        rv = WriteSharpObjectInfo(objvec[i]);
        if (NS_FAILED(rv)) break;
    }

    delete[] objvec;
    if (NS_FAILED(rv))
        return rv;

    // Enumerate mDocumentMap, writing nsFastLoadMuxedDocumentInfo records
    count = PL_DHashTableEnumerate(&mDocumentMap, DocumentMapEnumerate, &rv);
    if (NS_FAILED(rv))
        return rv;

    NS_ASSERTION(count == footerPrefix.mNumMuxedDocuments,
                 "bad mDocumentMap enumeration!");

    // Write out make-like file dependencies.
    count = PL_DHashTableEnumerate(&mDependencyMap, DependencyMapEnumerate, &rv);
    if (NS_FAILED(rv))
        return rv;

    return NS_OK;
}

nsresult
nsFastLoadFileWriter::Init()
{
    if (!PL_DHashTableInit(&mIDMap, &idmap_DHashTableOps, (void *)this,
                           sizeof(nsIDMapEntry), PL_DHASH_MIN_SIZE)) {
        mIDMap.ops = nsnull;
        return NS_ERROR_OUT_OF_MEMORY;
    }

    if (!PL_DHashTableInit(&mObjectMap, &objmap_DHashTableOps, (void *)this,
                           sizeof(nsSharpObjectMapEntry), PL_DHASH_MIN_SIZE)) {
        mObjectMap.ops = nsnull;
        return NS_ERROR_OUT_OF_MEMORY;
    }

    if (!PL_DHashTableInit(&mDocumentMap, &strmap_DHashTableOps, (void *)this,
                           sizeof(nsDocumentMapWriteEntry),
                           PL_DHASH_MIN_SIZE)) {
        mDocumentMap.ops = nsnull;
        return NS_ERROR_OUT_OF_MEMORY;
    }

    if (!PL_DHashTableInit(&mURIMap, &objmap_DHashTableOps, (void *)this,
                           sizeof(nsURIMapWriteEntry), PL_DHASH_MIN_SIZE)) {
        mURIMap.ops = nsnull;
        return NS_ERROR_OUT_OF_MEMORY;
    }

    if (!PL_DHashTableInit(&mDependencyMap, &strmap_DHashTableOps, (void *)this,
                           sizeof(nsDependencyMapEntry), PL_DHASH_MIN_SIZE)) {
        mDependencyMap.ops = nsnull;
        return NS_ERROR_OUT_OF_MEMORY;
    }

    return NS_OK;
}

nsresult
nsFastLoadFileWriter::Open()
{
    nsresult rv;
    
    if (!mSeekableOutput)
        return NS_ERROR_FAILURE;

    rv = mSeekableOutput->Seek(nsISeekableStream::NS_SEEK_SET,
                               sizeof(nsFastLoadHeader));
    if (NS_FAILED(rv))
        return rv;

    return Init();
}

#define MFL_CHECKSUM_BUFSIZE    (6 * 8192)

NS_IMETHODIMP
nsFastLoadFileWriter::Close()
{
    nsresult rv;

    memcpy(mHeader.mMagic, magic, MFL_FILE_MAGIC_SIZE);
    mHeader.mChecksum = 0;
    mHeader.mVersion = MFL_FILE_VERSION;

    PRInt64 footerOffset;
    rv = mSeekableOutput->Tell(&footerOffset);

    LL_L2UI(mHeader.mFooterOffset, footerOffset);
    if (NS_FAILED(rv))
        return rv;

    // If there is a muxed document segment open, close it now by setting its
    // length, stored in the second PRUint32 of the segment.
    if (mCurrentDocumentMapEntry) {
        PRUint32 currentSegmentOffset =
            mCurrentDocumentMapEntry->mCurrentSegmentOffset;
        rv = mSeekableOutput->Seek(nsISeekableStream::NS_SEEK_SET,
                                   currentSegmentOffset + 4);
        if (NS_FAILED(rv))
            return rv;

        rv = Write32(mHeader.mFooterOffset - currentSegmentOffset);
        if (NS_FAILED(rv))
            return rv;

        // Seek back to the current offset to write the footer.
        rv = mSeekableOutput->Seek(nsISeekableStream::NS_SEEK_SET,
                                   mHeader.mFooterOffset);
        if (NS_FAILED(rv))
            return rv;

        mCurrentDocumentMapEntry = nsnull;
    }

    rv = WriteFooter();
    if (NS_FAILED(rv))
        return rv;
    PRInt64 fileSize;
    rv = mSeekableOutput->Tell(&fileSize);
    LL_L2UI(mHeader.mFileSize, fileSize);
    if (NS_FAILED(rv))
        return rv;

    rv = mSeekableOutput->Seek(nsISeekableStream::NS_SEEK_SET, 0);
    if (NS_FAILED(rv))
        return rv;

    rv = WriteHeader(&mHeader);
    if (NS_FAILED(rv))
        return rv;

    // Now compute the checksum, using mFileIO to get an input stream on the
    // underlying FastLoad file.
    if (mFileIO) {
        // Get the unbuffered output stream, which flushes the buffered header
        // so we can read and checksum it along with the rest of the file, and
        // which allows us to write the checksum directly.
        nsCOMPtr<nsIOutputStream> output;
        rv = mBufferAccess->GetUnbufferedStream(getter_AddRefs(output));
        if (NS_FAILED(rv) || !output)
            return NS_ERROR_UNEXPECTED;

        nsCOMPtr<nsIInputStream> input;
        rv = mFileIO->GetInputStream(getter_AddRefs(input));
        if (NS_FAILED(rv))
            return rv;
 
        // Seek the input stream to right after checksum/magic.
        nsCOMPtr<nsISeekableStream> seekable = do_QueryInterface(input);
        rv = seekable->Seek(nsISeekableStream::NS_SEEK_SET,
                            offsetof(nsFastLoadHeader, mVersion));
        if (NS_FAILED(rv))
            return rv;

        char buf[MFL_CHECKSUM_BUFSIZE];
        PRUint32 len, rem = 0;
        PRUint32 checksum = 0;

        // Ok, we're finally ready to checksum the FastLoad file we just wrote!
        while (NS_SUCCEEDED(rv =
                            input->Read(buf + rem, sizeof buf - rem, &len)) &&
               len) {
            len += rem;
            rem = NS_AccumulateFastLoadChecksum(&checksum,
                                                reinterpret_cast<PRUint8*>
                                                                (buf),
                                                len,
                                                PR_FALSE);
            if (rem)
                memcpy(buf, buf + len - rem, rem);
        }
        if (NS_FAILED(rv))
            return rv;

        if (rem) {
            NS_AccumulateFastLoadChecksum(&checksum,
                                          reinterpret_cast<PRUint8*>(buf),
                                          rem,
                                          PR_TRUE);
        }

        // Store the checksum in the FastLoad file header and remember it via
        // mHeader.mChecksum, for GetChecksum.
        seekable = do_QueryInterface(output);
        rv = seekable->Seek(nsISeekableStream::NS_SEEK_SET,
                            offsetof(nsFastLoadHeader, mChecksum));
        if (NS_FAILED(rv))
            return rv;

        mHeader.mChecksum = checksum;
        checksum = NS_SWAP32(checksum);
        PRUint32 bytesWritten;
        rv = output->Write(reinterpret_cast<char*>(&checksum),
                           sizeof checksum,
                           &bytesWritten);
        if (NS_FAILED(rv))
            return rv;
        if (bytesWritten != sizeof checksum)
            return NS_ERROR_FAILURE;
    }

    return mOutputStream->Close();
}

// Pseudo-tag used as flag between WriteSingleRefObject and WriteObjectCommon.
#define MFL_SINGLE_REF_PSEUDO_TAG       PR_BIT(MFL_OBJECT_TAG_BITS)

nsresult
nsFastLoadFileWriter::WriteObjectCommon(nsISupports* aObject,
                                        PRBool aIsStrongRef,
                                        PRUint32 aTags)
{
    nsrefcnt rc;
    nsresult rv;

    NS_ASSERTION((NS_PTR_TO_INT32(aObject) & MFL_OBJECT_DEF_TAG) == 0,
                 "odd nsISupports*, oh no!");

    // Here be manual refcounting dragons!
    rc = aObject->AddRef();
    NS_ASSERTION(rc != 0, "bad refcnt when writing aObject!");

    NSFastLoadOID oid;
    nsCOMPtr<nsIClassInfo> classInfo;

    if (rc == 2 && (aTags & MFL_SINGLE_REF_PSEUDO_TAG)) {
        // Dull object: only one strong ref and no weak refs in serialization.
        // Conservative: we don't trust the caller if there are more than two
        // refs (one from the AddRef above, one from the data structure that's
        // being serialized).
        oid = MFL_DULL_OBJECT_OID;
        aObject->Release();
    } else {
        // Object is presumed to be multiply connected through some combo of
        // strong and weak refs.  Hold onto it via mObjectMap.
        nsSharpObjectMapEntry* entry =
            static_cast<nsSharpObjectMapEntry*>
                       (PL_DHashTableOperate(&mObjectMap, aObject,
                                             PL_DHASH_ADD));
        if (!entry) {
            aObject->Release();
            return NS_ERROR_OUT_OF_MEMORY;
        }

        if (!entry->mObject) {
            // First time we've seen this object address: add it to mObjectMap
            // and serialize the object at the current stream offset.
            PRInt64 thisOffset;
            rv = Tell(&thisOffset);
            if (NS_FAILED(rv)) {
                aObject->Release();
                return rv;
            }

            // NB: aObject was already held, and mObject is a raw nsISupports*.
            entry->mObject = aObject;

            oid = (mObjectMap.entryCount << MFL_OBJECT_TAG_BITS);
            entry->mOID = oid;

            // NB: the (32-bit, fast) CID and object data follow the OID.
            entry->mInfo.mCIDOffset = thisOffset + sizeof(oid);
            entry->mInfo.mStrongRefCnt = aIsStrongRef ? 1 : 0;
            entry->mInfo.mWeakRefCnt   = aIsStrongRef ? 0 : 1;

            // Record in oid the fact that we're defining this object in the
            // stream, and get the object's class info here, so we can take
            // note of singletons in order to avoid reserializing them when
            // updating after reading.
            oid |= MFL_OBJECT_DEF_TAG;
            classInfo = do_QueryInterface(aObject);
            if (!classInfo) {
                NS_NOTREACHED("aObject must implement nsIClassInfo");
                return NS_ERROR_FAILURE;
            }

            PRUint32 flags;
            if (NS_SUCCEEDED(classInfo->GetFlags(&flags)) &&
                (flags & nsIClassInfo::SINGLETON)) {
                MFL_SET_SINGLETON_FLAG(&entry->mInfo);
            }
        } else {
            // Already serialized, recover oid and update the desired refcnt.
            oid = entry->mOID;
            if (aIsStrongRef) {
                ++entry->mInfo.mStrongRefCnt;
                NS_ASSERTION(entry->mInfo.mStrongRefCnt != 0,
                             "mStrongRefCnt overflow");
            } else {
                MFL_BUMP_WEAK_REFCNT(&entry->mInfo);
                NS_ASSERTION(MFL_GET_WEAK_REFCNT(&entry->mInfo) != 0,
                             "mWeakRefCnt overflow");
            }

            aObject->Release();
        }
    }

    if (!aIsStrongRef)
        oid |= MFL_WEAK_REF_TAG;
    oid |= (aTags & MFL_QUERY_INTERFACE_TAG);

    rv = Write32(oid ^ MFL_OID_XOR_KEY);
    if (NS_FAILED(rv))
        return rv;

    if (oid & MFL_OBJECT_DEF_TAG) {
        nsCOMPtr<nsISerializable> serializable(do_QueryInterface(aObject));
        if (!serializable) {
            NS_NOTREACHED("aObject must implement nsISerializable");
            return NS_ERROR_FAILURE;
        }

        nsCID slowCID;
        rv = classInfo->GetClassIDNoAlloc(&slowCID);
        if (NS_FAILED(rv))
            return rv;

        NSFastLoadID fastCID;
        rv = MapID(slowCID, &fastCID);
        if (NS_FAILED(rv))
            return rv;

        rv = WriteFastID(fastCID);
        if (NS_FAILED(rv))
            return rv;

        rv = serializable->Write(this);
        if (NS_FAILED(rv))
            return rv;
    }

    return NS_OK;
}

NS_IMETHODIMP
nsFastLoadFileWriter::WriteObject(nsISupports* aObject, PRBool aIsStrongRef)
{
#ifdef NS_DEBUG
    nsCOMPtr<nsISupports> rootObject(do_QueryInterface(aObject));

    NS_ASSERTION(rootObject.get() == aObject,
                 "bad call to WriteObject -- call WriteCompoundObject!");
#endif

    return WriteObjectCommon(aObject, aIsStrongRef, 0);
}

NS_IMETHODIMP
nsFastLoadFileWriter::WriteSingleRefObject(nsISupports* aObject)
{
#ifdef NS_DEBUG
    nsCOMPtr<nsISupports> rootObject(do_QueryInterface(aObject));

    NS_ASSERTION(rootObject.get() == aObject,
                 "bad call to WriteSingleRefObject -- call WriteCompoundObject!");
#endif

    return WriteObjectCommon(aObject, PR_TRUE, MFL_SINGLE_REF_PSEUDO_TAG);
}

NS_IMETHODIMP
nsFastLoadFileWriter::WriteCompoundObject(nsISupports* aObject,
                                          const nsIID& aIID,
                                          PRBool aIsStrongRef)
{
    nsresult rv;
    nsCOMPtr<nsISupports> rootObject(do_QueryInterface(aObject));
    
    // We could assert that |rootObject != aObject|, but that would prevent
    // callers who don't know whether they're dealing with the primary
    // nsISupports pointer (e.g., they don't know which implementation of
    // nsIURI they have) from using this function.

#ifdef NS_DEBUG
    nsCOMPtr<nsISupports> roundtrip;
    rootObject->QueryInterface(aIID, getter_AddRefs(roundtrip));
    NS_ASSERTION(roundtrip.get() == aObject,
                 "bad aggregation or multiple inheritance detected by call to "
                 "WriteCompoundObject!");
#endif

    rv = WriteObjectCommon(rootObject, aIsStrongRef, MFL_QUERY_INTERFACE_TAG);
    if (NS_FAILED(rv))
        return rv;

    NSFastLoadID iid;
    rv = MapID(aIID, &iid);
    if (NS_FAILED(rv))
        return rv;

    return WriteFastID(iid);
}

NS_IMETHODIMP
nsFastLoadFileWriter::WriteID(const nsID& aID)
{
    nsresult rv;
    NSFastLoadID fastID;

    rv = MapID(aID, &fastID);
    if (NS_FAILED(rv))
        return rv;

    return WriteFastID(fastID);
}

NS_IMETHODIMP
nsFastLoadFileWriter::Seek(PRInt32 aWhence, PRInt64 aOffset)
{
    mCurrentDocumentMapEntry = nsnull;
    return mSeekableOutput->Seek(aWhence, aOffset);
}

NS_IMETHODIMP
nsFastLoadFileWriter::Tell(PRInt64 *aResult)
{
    return mSeekableOutput->Tell(aResult);
}

NS_IMETHODIMP
nsFastLoadFileWriter::SetEOF()
{
    return mSeekableOutput->SetEOF();
}

NS_IMETHODIMP
nsFastLoadFileWriter::SetOutputStream(nsIOutputStream *aStream)
{
    nsresult rv = nsBinaryOutputStream::SetOutputStream(aStream);
    mSeekableOutput = do_QueryInterface(mOutputStream);
    return rv;
}

NS_COM nsresult
NS_NewFastLoadFileWriter(nsIObjectOutputStream* *aResult,
                         nsIOutputStream* aDestStream,
                         nsIFastLoadFileIO* aFileIO)
{
    nsFastLoadFileWriter* writer =
        new nsFastLoadFileWriter(aDestStream, aFileIO);
    if (!writer)
        return NS_ERROR_OUT_OF_MEMORY;

    // Stabilize writer's refcnt.
    nsCOMPtr<nsIObjectOutputStream> stream(writer);

    nsresult rv = writer->Open();
    if (NS_FAILED(rv))
        return rv;

    *aResult = stream;
    NS_ADDREF(*aResult);
    return NS_OK;
}

// -------------------------- nsFastLoadFileUpdater --------------------------

NS_IMPL_ISUPPORTS_INHERITED0(nsFastLoadFileUpdater,
                             nsFastLoadFileWriter)

PLDHashOperator
nsFastLoadFileUpdater::CopyReadDocumentMapEntryToUpdater(PLDHashTable *aTable,
                                                         PLDHashEntryHdr *aHdr,
                                                         PRUint32 aNumber,
                                                         void *aData)
{
    nsDocumentMapReadEntry* readEntry =
        static_cast<nsDocumentMapReadEntry*>(aHdr);
    nsFastLoadFileUpdater* updater =
        reinterpret_cast<nsFastLoadFileUpdater*>(aData);

    void* spec = nsMemory::Clone(readEntry->mString,
                                 strlen(readEntry->mString) + 1);
    if (!spec)
        return PL_DHASH_STOP;

    nsDocumentMapWriteEntry* writeEntry =
        static_cast<nsDocumentMapWriteEntry*>
                   (PL_DHashTableOperate(&updater->mDocumentMap, spec,
                                         PL_DHASH_ADD));
    if (!writeEntry) {
        nsMemory::Free(spec);
        return PL_DHASH_STOP;
    }

    writeEntry->mString = reinterpret_cast<const char*>(spec);
    writeEntry->mURI = nsnull;
    writeEntry->mInitialSegmentOffset = readEntry->mInitialSegmentOffset;
    writeEntry->mCurrentSegmentOffset = 0;
    return PL_DHASH_NEXT;
}

nsresult
nsFastLoadFileUpdater::Open(nsFastLoadFileReader* aReader)
{
    nsresult rv;
    rv = nsFastLoadFileWriter::Init();
    if (NS_FAILED(rv))
        return rv;

    PRUint32 i, n;

    // Map from dense, zero-based, uint32 NSFastLoadID in reader to 16-byte
    // nsID in updater.
    nsID* readIDMap = aReader->mFooter.mIDMap;
    for (i = 0, n = aReader->mFooter.mNumIDs; i < n; i++) {
        NSFastLoadID fastID;
        rv = MapID(readIDMap[i], &fastID);
        NS_ASSERTION(fastID == i + 1, "huh?");
        if (NS_FAILED(rv))
            return rv;
    }

    // Map from reader dense, zero-based MFL_OID_TO_SHARP_INDEX(oid) to sharp
    // object offset and refcnt information in updater.
    nsFastLoadFileReader::nsObjectMapEntry* readObjectMap =
        aReader->mFooter.mObjectMap;

    // Prepare to save aReader state in case we need to seek back and read a
    // singleton object that might otherwise get written by this updater.
    nsDocumentMapReadEntry* saveDocMapEntry = nsnull;
    PRInt64 saveOffset = 0;

    for (i = 0, n = aReader->mFooter.mNumSharpObjects; i < n; i++) {
        nsFastLoadFileReader::nsObjectMapEntry* readEntry = &readObjectMap[i];

        NS_ASSERTION(readEntry->mCIDOffset != 0,
                     "fastload updater: mCIDOffset cannot be zero!");

        // If the reader didn't read this object but it's a singleton, we must
        // "deserialize" it now, to discover its one and only root nsISupports
        // address.  The object already exists in memory if it was created at
        // startup without resort to the FastLoad file.  The canonical example
        // is the system principal object held by all XUL JS scripts.

        nsISupports* obj = readEntry->mReadObject;
        if (!obj && MFL_GET_SINGLETON_FLAG(readEntry)) {
            if (!saveDocMapEntry) {
                rv = aReader->Tell(&saveOffset);
                if (NS_FAILED(rv))
                    return rv;

                saveDocMapEntry = aReader->mCurrentDocumentMapEntry;
                aReader->mCurrentDocumentMapEntry = nsnull;
            }

            rv = aReader->Seek(nsISeekableStream::NS_SEEK_SET,
                                     readEntry->mCIDOffset);
            if (NS_FAILED(rv))
                return rv;

            rv = aReader
                 ->DeserializeObject(getter_AddRefs(readEntry->mReadObject));
            if (NS_FAILED(rv))
                return rv;
            obj = readEntry->mReadObject;

            // Don't forget to set mSkipOffset in case someone calls the reader
            // to "deserialize" (yet again) the object we just read.
            //
            // Say the singleton is the system principal, and the FastLoad file
            // contains data for navigator.xul including scripts and functions.
            // If we update the FastLoad file to contain data for messenger.xul
            // in a separate session started via mozilla -mail, *and during the
            // same FastLoad episode in this session* race to open a navigator
            // window, we will attempt to read all objects serialized in the
            // navigator.xul portion of the FastLoad file.
            //
            // mSkipOffset must be set in such a case so the reader can skip
            // the system principal's serialized data, because the updater for
            // messenger.xul being opened here has already read it.

            rv = aReader->Tell(&readEntry->mSkipOffset);
            if (NS_FAILED(rv))
                return rv;
        }

        NSFastLoadOID oid = MFL_SHARP_INDEX_TO_OID(i);
        void* key = obj
                    ? reinterpret_cast<void*>(obj)
                    : reinterpret_cast<void*>((oid | MFL_OBJECT_DEF_TAG));

        nsSharpObjectMapEntry* writeEntry =
            static_cast<nsSharpObjectMapEntry*>
                       (PL_DHashTableOperate(&mObjectMap, key,
                                             PL_DHASH_ADD));
        if (!writeEntry)
            return NS_ERROR_OUT_OF_MEMORY;

        // Hold the object if there is one, so that objmap_ClearEntry can
        // release the reference.
        NS_IF_ADDREF(obj);
        writeEntry->mObject = reinterpret_cast<nsISupports*>(key);
        writeEntry->mOID = oid;
        writeEntry->mInfo.mCIDOffset = readEntry->mCIDOffset;
        writeEntry->mInfo.mStrongRefCnt = readEntry->mSaveStrongRefCnt;
        writeEntry->mInfo.mWeakRefCnt = readEntry->mSaveWeakRefCnt;
    }

    // If we had to read any singletons, restore aReader's saved state.
    if (saveDocMapEntry) {
        rv = aReader->Seek(nsISeekableStream::NS_SEEK_SET, saveOffset);
        if (NS_FAILED(rv))
            return rv;

        aReader->mCurrentDocumentMapEntry = saveDocMapEntry;
    }

    // Copy URI spec string and initial segment offset in FastLoad file from
    // nsDocumentMapReadEntry in reader to nsDocumentMapWriteEntry in updater.
    // If we didn't enumerate all entries, we ran out of memory.
    n = PL_DHashTableEnumerate(&aReader->mFooter.mDocumentMap,
                               CopyReadDocumentMapEntryToUpdater,
                               this);
    if (n != aReader->mFooter.mDocumentMap.entryCount)
        return NS_ERROR_OUT_OF_MEMORY;

    // Copy source filename dependencies from reader to updater.
    nsISupportsArray* readDeps = aReader->mFooter.mDependencies;
    rv = readDeps->Count(&n);
    if (NS_FAILED(rv))
        return rv;

    for (i = 0; i < n; i++) {
        nsCOMPtr<nsIFile> file;
        rv = readDeps->GetElementAt(i, getter_AddRefs(file));
        if (NS_FAILED(rv))
            return rv;

        rv = AddDependency(file);
        if (NS_FAILED(rv))
            return rv;
    }

    // Seek to the reader's footer offset so we overwrite the footer.  First,
    // update the header to have a zero mFooterOffset, which will invalidate
    // the FastLoad file on next startup read attempt, should we crash before
    // completing this update.
    rv = mSeekableOutput->Seek(nsISeekableStream::NS_SEEK_SET,
                               offsetof(nsFastLoadHeader, mFooterOffset));
    if (NS_FAILED(rv))
        return rv;

    rv = Write32(0);
    if (NS_FAILED(rv))
        return rv;

    rv = mSeekableOutput->Seek(nsISeekableStream::NS_SEEK_SET,
                               aReader->mHeader.mFooterOffset);
    if (NS_FAILED(rv))
        return rv;

    return NS_OK;
}

NS_IMETHODIMP
nsFastLoadFileUpdater::Close()
{
    // Call base-class Close implementation, which uses mFileIO.
    nsresult rv = nsFastLoadFileWriter::Close();

    // Break degenerate cycle from this->mFileIO to this.
    mFileIO = nsnull;
    return rv;
}

NS_COM nsresult
NS_NewFastLoadFileUpdater(nsIObjectOutputStream* *aResult,
                          nsIFastLoadFileIO *aFileIO,
                          nsIObjectInputStream* aReaderAsStream)
{
    // Make sure that aReaderAsStream is an nsFastLoadFileReader.
    nsCOMPtr<nsIFastLoadFileReader> reader(do_QueryInterface(aReaderAsStream));
    if (!reader)
        return NS_ERROR_UNEXPECTED;

    nsCOMPtr<nsIOutputStream> output;
    nsresult rv = aFileIO->GetOutputStream(getter_AddRefs(output));
    if (NS_FAILED(rv))
        return rv;

    nsFastLoadFileUpdater* updater = new nsFastLoadFileUpdater(output, aFileIO);
    if (!updater)
        return NS_ERROR_OUT_OF_MEMORY;

    // Stabilize updater's refcnt.
    nsCOMPtr<nsIObjectOutputStream> stream(updater);

    rv = updater->Open(static_cast<nsFastLoadFileReader*>(aReaderAsStream));
    if (NS_FAILED(rv))
        return rv;

    *aResult = stream;
    NS_ADDREF(*aResult);
    return NS_OK;
}