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

Untracked file

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
/* vim:set ts=4 sw=4 sts=4 et cin: */
/* ***** 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.
 *
 * The Initial Developer of the Original Code is
 * Netscape Communications Corporation.
 * Portions created by the Initial Developer are Copyright (C) 2002
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *   Darin Fisher <darin@netscape.com>
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either 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 "nsHttpConnectionMgr.h"
#include "nsHttpConnection.h"
#include "nsHttpPipeline.h"
#include "nsHttpHandler.h"
#include "nsAutoLock.h"
#include "nsNetCID.h"
#include "nsCOMPtr.h"

#include "nsIServiceManager.h"

// defined by the socket transport service while active
extern PRThread *gSocketThread;

static NS_DEFINE_CID(kSocketTransportServiceCID, NS_SOCKETTRANSPORTSERVICE_CID);

//-----------------------------------------------------------------------------

nsHttpConnectionMgr::nsHttpConnectionMgr()
    : mRef(0)
    , mMonitor(nsAutoMonitor::NewMonitor("nsHttpConnectionMgr"))
    , mMaxConns(0)
    , mMaxConnsPerHost(0)
    , mMaxConnsPerProxy(0)
    , mMaxPersistConnsPerHost(0)
    , mMaxPersistConnsPerProxy(0)
    , mNumActiveConns(0)
    , mNumIdleConns(0)
{
    LOG(("Creating nsHttpConnectionMgr @%x\n", this));
}

nsHttpConnectionMgr::~nsHttpConnectionMgr()
{
    LOG(("Destroying nsHttpConnectionMgr @%x\n", this));
 
    if (mMonitor)
        nsAutoMonitor::DestroyMonitor(mMonitor);
}

nsresult
nsHttpConnectionMgr::Init(PRUint16 maxConns,
                          PRUint16 maxConnsPerHost,
                          PRUint16 maxConnsPerProxy,
                          PRUint16 maxPersistConnsPerHost,
                          PRUint16 maxPersistConnsPerProxy,
                          PRUint16 maxRequestDelay,
                          PRUint16 maxPipelinedRequests)
{
    LOG(("nsHttpConnectionMgr::Init\n"));

    nsAutoMonitor mon(mMonitor);

    // do nothing if already initialized
    if (mSTEventTarget)
        return NS_OK;

    // no need to do any special synchronization here since there cannot be
    // any activity on the socket thread (because Shutdown is synchronous).
    mMaxConns = maxConns;
    mMaxConnsPerHost = maxConnsPerHost;
    mMaxConnsPerProxy = maxConnsPerProxy;
    mMaxPersistConnsPerHost = maxPersistConnsPerHost;
    mMaxPersistConnsPerProxy = maxPersistConnsPerProxy;
    mMaxRequestDelay = maxRequestDelay;
    mMaxPipelinedRequests = maxPipelinedRequests;

    nsresult rv;
    mSTEventTarget = do_GetService(kSocketTransportServiceCID, &rv);
    return rv;
}

nsresult
nsHttpConnectionMgr::Shutdown()
{
    LOG(("nsHttpConnectionMgr::Shutdown\n"));

    nsAutoMonitor mon(mMonitor);

    // do nothing if already shutdown
    if (!mSTEventTarget)
        return NS_OK;

    nsresult rv = PostEvent(&nsHttpConnectionMgr::OnMsgShutdown);

    // release our reference to the STS to prevent further events
    // from being posted.  this is how we indicate that we are
    // shutting down.
    mSTEventTarget = 0;

    if (NS_FAILED(rv)) {
        NS_WARNING("unable to post SHUTDOWN message\n");
        return rv;
    }

    // wait for shutdown event to complete
    mon.Wait();
    return NS_OK;
}

nsresult
nsHttpConnectionMgr::PostEvent(nsConnEventHandler handler, nsresult status, void *param)
{
    nsAutoMonitor mon(mMonitor);

    nsresult rv;
    if (!mSTEventTarget) {
        NS_WARNING("cannot post event if not initialized");
        rv = NS_ERROR_NOT_INITIALIZED;
    }
    else {
        PLEvent *event = new nsConnEvent(this, handler, status, param);
        if (!event)
            rv = NS_ERROR_OUT_OF_MEMORY;
        else {
            rv = mSTEventTarget->PostEvent(event);
            if (NS_FAILED(rv))
                PL_DestroyEvent(event);
        }
    }
    return rv;
}

//-----------------------------------------------------------------------------

nsresult
nsHttpConnectionMgr::AddTransaction(nsHttpTransaction *trans)
{
    LOG(("nsHttpConnectionMgr::AddTransaction [trans=%x]\n", trans));

    NS_ADDREF(trans);
    nsresult rv = PostEvent(&nsHttpConnectionMgr::OnMsgNewTransaction, NS_OK, trans);
    if (NS_FAILED(rv))
        NS_RELEASE(trans);
    return rv;
}

nsresult
nsHttpConnectionMgr::CancelTransaction(nsHttpTransaction *trans, nsresult reason)
{
    LOG(("nsHttpConnectionMgr::CancelTransaction [trans=%x reason=%x]\n", trans, reason));

    NS_ADDREF(trans);
    nsresult rv = PostEvent(&nsHttpConnectionMgr::OnMsgCancelTransaction, reason, trans);
    if (NS_FAILED(rv))
        NS_RELEASE(trans);
    return rv;
}

nsresult
nsHttpConnectionMgr::PruneDeadConnections()
{
    return PostEvent(&nsHttpConnectionMgr::OnMsgPruneDeadConnections);
}

nsresult
nsHttpConnectionMgr::GetSocketThreadEventTarget(nsIEventTarget **target)
{
    nsAutoMonitor mon(mMonitor);
    NS_IF_ADDREF(*target = mSTEventTarget);
    return NS_OK;
}

void
nsHttpConnectionMgr::AddTransactionToPipeline(nsHttpPipeline *pipeline)
{
    LOG(("nsHttpConnectionMgr::AddTransactionToPipeline [pipeline=%x]\n", pipeline));

    NS_ASSERTION(PR_GetCurrentThread() == gSocketThread, "wrong thread");

    nsHttpConnectionInfo *ci = nsnull;
    pipeline->GetConnectionInfo(&ci);
    if (ci) {
        nsCStringKey key(ci->HashKey());
        nsConnectionEntry *ent = (nsConnectionEntry *) mCT.Get(&key);
        if (ent) {
            // search for another request to pipeline...
            PRInt32 i, count = ent->mPendingQ.Count();
            for (i=0; i<count; ++i) {
                nsHttpTransaction *trans = (nsHttpTransaction *) ent->mPendingQ[i];
                if (trans->Caps() & NS_HTTP_ALLOW_PIPELINING) {
                    pipeline->AddTransaction(trans);

                    // remove transaction from pending queue
                    ent->mPendingQ.RemoveElementAt(i);
                    NS_RELEASE(trans);
                    break;
                }
            }
        }
    }
}

nsresult
nsHttpConnectionMgr::ReclaimConnection(nsHttpConnection *conn)
{
    LOG(("nsHttpConnectionMgr::ReclaimConnection [conn=%x]\n", conn));

    NS_ADDREF(conn);
    nsresult rv = PostEvent(&nsHttpConnectionMgr::OnMsgReclaimConnection, NS_OK, conn);
    if (NS_FAILED(rv))
        NS_RELEASE(conn);
    return rv;
}

nsresult
nsHttpConnectionMgr::UpdateParam(nsParamName name, PRUint16 value)
{
    PRUint32 param = (PRUint32(name) << 16) | PRUint32(value);
    return PostEvent(&nsHttpConnectionMgr::OnMsgUpdateParam, NS_OK, (void *) param);
}

nsresult
nsHttpConnectionMgr::ProcessPendingQ(nsHttpConnectionInfo *ci)
{
    LOG(("nsHttpConnectionMgr::ProcessPendingQ [ci=%s]\n", ci->HashKey().get()));

    NS_ADDREF(ci);
    nsresult rv = PostEvent(&nsHttpConnectionMgr::OnMsgProcessPendingQ, NS_OK, ci);
    if (NS_FAILED(rv))
        NS_RELEASE(ci);
    return rv;
}

//-----------------------------------------------------------------------------
// enumeration callbacks

PRIntn PR_CALLBACK
nsHttpConnectionMgr::ProcessOneTransactionCB(nsHashKey *key, void *data, void *closure)
{
    nsHttpConnectionMgr *self = (nsHttpConnectionMgr *) closure;
    nsConnectionEntry *ent = (nsConnectionEntry *) data;

    if (self->ProcessPendingQForEntry(ent))
        return kHashEnumerateStop;

    return kHashEnumerateNext;
}

PRIntn PR_CALLBACK
nsHttpConnectionMgr::PurgeOneIdleConnectionCB(nsHashKey *key, void *data, void *closure)
{
    nsHttpConnectionMgr *self = (nsHttpConnectionMgr *) closure;
    nsConnectionEntry *ent = (nsConnectionEntry *) data;

    if (ent->mIdleConns.Count() > 0) {
        nsHttpConnection *conn = (nsHttpConnection *) ent->mIdleConns[0];
        ent->mIdleConns.RemoveElementAt(0);
        conn->Close(NS_ERROR_ABORT);
        NS_RELEASE(conn);
        self->mNumIdleConns--;
        return kHashEnumerateStop;
    }

    return kHashEnumerateNext;
}

PRIntn PR_CALLBACK
nsHttpConnectionMgr::PruneDeadConnectionsCB(nsHashKey *key, void *data, void *closure)
{
    nsHttpConnectionMgr *self = (nsHttpConnectionMgr *) closure;
    nsConnectionEntry *ent = (nsConnectionEntry *) data;

    LOG(("  pruning [ci=%s]\n", ent->mConnInfo->HashKey().get()));

    PRInt32 count = ent->mIdleConns.Count();
    if (count > 0) {
        for (PRInt32 i=count-1; i>=0; --i) {
            nsHttpConnection *conn = (nsHttpConnection *) ent->mIdleConns[i];
            if (!conn->CanReuse()) {
                ent->mIdleConns.RemoveElementAt(i);
                conn->Close(NS_ERROR_ABORT);
                NS_RELEASE(conn);
                self->mNumIdleConns--;
            }
        }
    }

#ifdef DEBUG
    count = ent->mActiveConns.Count();
    if (count > 0) {
        for (PRInt32 i=count-1; i>=0; --i) {
            nsHttpConnection *conn = (nsHttpConnection *) ent->mActiveConns[i];
            LOG(("    active conn [%x] with trans [%x]\n", conn, conn->Transaction()));
        }
    }
#endif

    // if this entry is empty, then we can remove it.
    if (ent->mIdleConns.Count()   == 0 &&
        ent->mActiveConns.Count() == 0 &&
        ent->mPendingQ.Count()    == 0) {
        LOG(("    removing empty connection entry\n"));
        delete ent;
        return kHashEnumerateRemove;
    }

    // else, use this opportunity to compact our arrays...
    ent->mIdleConns.Compact();
    ent->mActiveConns.Compact();
    ent->mPendingQ.Compact();

    return kHashEnumerateNext;
}

PRIntn PR_CALLBACK
nsHttpConnectionMgr::ShutdownPassCB(nsHashKey *key, void *data, void *closure)
{
    nsHttpConnectionMgr *self = (nsHttpConnectionMgr *) closure;
    nsConnectionEntry *ent = (nsConnectionEntry *) data;

    nsHttpTransaction *trans;
    nsHttpConnection *conn;

    // close all active connections
    while (ent->mActiveConns.Count()) {
        conn = (nsHttpConnection *) ent->mActiveConns[0];

        ent->mActiveConns.RemoveElementAt(0);
        self->mNumActiveConns--;

        conn->Close(NS_ERROR_ABORT);
        NS_RELEASE(conn);
    }

    // close all idle connections
    while (ent->mIdleConns.Count()) {
        conn = (nsHttpConnection *) ent->mIdleConns[0];

        ent->mIdleConns.RemoveElementAt(0);
        self->mNumIdleConns--;

        conn->Close(NS_ERROR_ABORT);
        NS_RELEASE(conn);
    }

    // close all pending transactions
    while (ent->mPendingQ.Count()) {
        trans = (nsHttpTransaction *) ent->mPendingQ[0];

        ent->mPendingQ.RemoveElementAt(0);

        trans->Close(NS_ERROR_ABORT);
        NS_RELEASE(trans);
    }

    delete ent;
    return kHashEnumerateRemove;
}

//-----------------------------------------------------------------------------

PRBool
nsHttpConnectionMgr::ProcessPendingQForEntry(nsConnectionEntry *ent)
{
    LOG(("nsHttpConnectionMgr::ProcessPendingQForEntry [ci=%s]\n",
        ent->mConnInfo->HashKey().get()));

    PRInt32 i, count = ent->mPendingQ.Count();
    if (count > 0) {
        LOG(("  pending-count=%u\n", count));
        nsHttpTransaction *trans = nsnull;
        nsHttpConnection *conn = nsnull;
        for (i=0; i<count; ++i) {
            trans = (nsHttpTransaction *) ent->mPendingQ[i];
            GetConnection(ent, trans->Caps(), &conn);
            if (conn)
                break;
        }
        if (conn) {
            LOG(("  dispatching pending transaction...\n"));

            // remove pending transaction
            ent->mPendingQ.RemoveElementAt(i);

            nsresult rv = DispatchTransaction(ent, trans, trans->Caps(), conn);
            if (NS_SUCCEEDED(rv))
                NS_RELEASE(trans);
            else {
                LOG(("  DispatchTransaction failed [rv=%x]\n", rv));
                // on failure, just put the transaction back
                ent->mPendingQ.InsertElementAt(trans, i);
                // might be something wrong with the connection... close it.
                conn->Close(rv);
            }

            NS_RELEASE(conn);
            return PR_TRUE;
        }
    }
    return PR_FALSE;
}

// we're at the active connection limit if any one of the following conditions is true:
//  (1) at max-connections
//  (2) keep-alive enabled and at max-persistent-connections-per-server/proxy
//  (3) keep-alive disabled and at max-connections-per-server
PRBool
nsHttpConnectionMgr::AtActiveConnectionLimit(nsConnectionEntry *ent, PRUint8 caps)
{
    nsHttpConnectionInfo *ci = ent->mConnInfo;

    LOG(("nsHttpConnectionMgr::AtActiveConnectionLimit [ci=%s caps=%x]\n",
        ci->HashKey().get(), caps));

    // use >= just to be safe
    if (mNumActiveConns >= mMaxConns) {
        LOG(("  num active conns == max conns\n"));
        return PR_TRUE;
    }

    nsHttpConnection *conn;
    PRInt32 i, totalCount, persistCount = 0;
    
    totalCount = ent->mActiveConns.Count();

    // count the number of persistent connections
    for (i=0; i<totalCount; ++i) {
        conn = (nsHttpConnection *) ent->mActiveConns[i];
        if (conn->IsKeepAlive()) // XXX make sure this is thread-safe
            persistCount++;
    }

    LOG(("   total=%d, persist=%d\n", totalCount, persistCount));

    PRUint16 maxConns;
    PRUint16 maxPersistConns;

    if (ci->UsingHttpProxy() && !ci->UsingSSL()) {
        maxConns = mMaxConnsPerProxy;
        maxPersistConns = mMaxPersistConnsPerProxy;
    }
    else {
        maxConns = mMaxConnsPerHost;
        maxPersistConns = mMaxPersistConnsPerHost;
    }

    // use >= just to be safe
    return (totalCount >= maxConns) || ( (caps & NS_HTTP_ALLOW_KEEPALIVE) &&
                                         (persistCount >= maxPersistConns) );
}

void
nsHttpConnectionMgr::GetConnection(nsConnectionEntry *ent, PRUint8 caps,
                                   nsHttpConnection **result)
{
    LOG(("nsHttpConnectionMgr::GetConnection [ci=%s caps=%x]\n",
        ent->mConnInfo->HashKey().get(), PRUint32(caps)));

    *result = nsnull;

    if (AtActiveConnectionLimit(ent, caps)) {
        LOG(("  at active connection limit!\n"));
        return;
    }

    nsHttpConnection *conn = nsnull;

    if (caps & NS_HTTP_ALLOW_KEEPALIVE) {
        // search the idle connection list
        while (!conn && (ent->mIdleConns.Count() > 0)) {
            conn = (nsHttpConnection *) ent->mIdleConns[0];
            // we check if the connection can be reused before even checking if
            // it is a "matching" connection.
            if (!conn->CanReuse()) {
                LOG(("   dropping stale connection: [conn=%x]\n", conn));
                conn->Close(NS_ERROR_ABORT);
                NS_RELEASE(conn);
            }
            else
                LOG(("   reusing connection [conn=%x]\n", conn));
            ent->mIdleConns.RemoveElementAt(0);
            mNumIdleConns--;
        }
    }

    if (!conn) {
        conn = new nsHttpConnection();
        if (!conn)
            return;
        NS_ADDREF(conn);

        nsresult rv = conn->Init(ent->mConnInfo, mMaxRequestDelay);
        if (NS_FAILED(rv)) {
            NS_RELEASE(conn);
            return;
        }
        
        // We created a new connection that will become active, purge the
        // oldest idle connection if we've reached the upper limit.
        if (mNumIdleConns + mNumActiveConns + 1 > mMaxConns)
            mCT.Enumerate(PurgeOneIdleConnectionCB, this);

        // XXX this just purges a random idle connection.  we should instead
        // enumerate the entire hash table to find the eldest idle connection.
    }

    *result = conn;
}

nsresult
nsHttpConnectionMgr::DispatchTransaction(nsConnectionEntry *ent,
                                         nsAHttpTransaction *trans,
                                         PRUint8 caps,
                                         nsHttpConnection *conn)
{
    LOG(("nsHttpConnectionMgr::DispatchTransaction [ci=%s trans=%x caps=%x conn=%x]\n",
        ent->mConnInfo->HashKey().get(), trans, caps, conn));

    nsConnectionHandle *handle = new nsConnectionHandle(conn);
    if (!handle)
        return NS_ERROR_OUT_OF_MEMORY;
    NS_ADDREF(handle);

    nsHttpPipeline *pipeline = nsnull;
    if (conn->SupportsPipelining() && (caps & NS_HTTP_ALLOW_PIPELINING)) {
        LOG(("  looking to build pipeline...\n"));
        if (BuildPipeline(ent, trans, &pipeline))
            trans = pipeline;
    }

    // hold an owning ref to this connection
    ent->mActiveConns.AppendElement(conn);
    mNumActiveConns++;
    NS_ADDREF(conn);

    // give the transaction the indirect reference to the connection.
    trans->SetConnection(handle);

    nsresult rv = conn->Activate(trans, caps);

    if (NS_FAILED(rv)) {
        LOG(("  conn->Activate failed [rv=%x]\n", rv));
        ent->mActiveConns.RemoveElement(conn);
        mNumActiveConns--;
        // sever back references to connection, and do so without triggering
        // a call to ReclaimConnection ;-)
        trans->SetConnection(nsnull);
        NS_RELEASE(handle->mConn);
        // destroy the connection
        NS_RELEASE(conn);
    }

    // if we were unable to activate the pipeline, then this will destroy
    // the pipeline, which will cause each the transactions owned by the 
    // pipeline to be restarted.
    NS_IF_RELEASE(pipeline);

    NS_RELEASE(handle);
    return rv;
}

PRBool
nsHttpConnectionMgr::BuildPipeline(nsConnectionEntry *ent,
                                   nsAHttpTransaction *firstTrans,
                                   nsHttpPipeline **result)
{
    if (mMaxPipelinedRequests < 2)
        return PR_FALSE;

    nsHttpPipeline *pipeline = nsnull;
    nsHttpTransaction *trans;

    PRInt32 i = 0, numAdded = 0;
    while (i < ent->mPendingQ.Count()) {
        trans = (nsHttpTransaction *) ent->mPendingQ[i];
        if (trans->Caps() & NS_HTTP_ALLOW_PIPELINING) {
            if (numAdded == 0) {
                pipeline = new nsHttpPipeline;
                if (!pipeline)
                    return PR_FALSE;
                pipeline->AddTransaction(firstTrans);
                numAdded = 1;
            }
            pipeline->AddTransaction(trans);

            // remove transaction from pending queue
            ent->mPendingQ.RemoveElementAt(i);
            NS_RELEASE(trans);

            if (++numAdded == mMaxPipelinedRequests)
                break;
        }
        else
            ++i; // skip to next pending transaction
    }

    if (numAdded == 0)
        return PR_FALSE;

    LOG(("  pipelined %u transactions\n", numAdded));
    NS_ADDREF(*result = pipeline);
    return PR_TRUE;
}

nsresult
nsHttpConnectionMgr::ProcessNewTransaction(nsHttpTransaction *trans)
{
    // since "adds" and "cancels" are processed asynchronously and because
    // various events might trigger an "add" directly on the socket thread,
    // we must take care to avoid dispatching a transaction that has already
    // been canceled (see bug 190001).
    if (NS_FAILED(trans->Status())) {
        LOG(("  transaction was canceled... dropping event!\n"));
        return NS_OK;
    }

    PRUint8 caps = trans->Caps();
    nsHttpConnectionInfo *ci = trans->ConnectionInfo();
    NS_ASSERTION(ci, "no connection info");

    nsCStringKey key(ci->HashKey());
    nsConnectionEntry *ent = (nsConnectionEntry *) mCT.Get(&key);
    if (!ent) {
        ent = new nsConnectionEntry(ci);
        if (!ent)
            return NS_ERROR_OUT_OF_MEMORY;
        mCT.Put(&key, ent);
    }

    nsHttpConnection *conn;

    // check if the transaction already has a sticky reference to a connection.
    // if so, then we can just use it directly.  XXX check if alive??
    // XXX add a TakeConnection method or something to make this clearer!
    nsConnectionHandle *handle = (nsConnectionHandle *) trans->Connection();
    if (handle) {
        NS_ASSERTION(caps & NS_HTTP_STICKY_CONNECTION, "unexpected caps");
        NS_ASSERTION(handle->mConn, "no connection");

        // steal reference from connection handle.
        // XXX prevent SetConnection(nsnull) from calling ReclaimConnection
        conn = handle->mConn;
        handle->mConn = nsnull;

        // destroy connection handle.
        trans->SetConnection(nsnull);

        // remove sticky connection from active connection list; we'll add it
        // right back in DispatchTransaction.
        if (ent->mActiveConns.RemoveElement(conn))
            mNumActiveConns--;
        else {
            NS_ERROR("sticky connection not found in active list");
            return NS_ERROR_UNEXPECTED;
        }
    }
    else
        GetConnection(ent, caps, &conn);

    nsresult rv;
    if (!conn) {
        LOG(("  adding transaction to pending queue [trans=%x pending-count=%u]\n",
            trans, ent->mPendingQ.Count()+1));
        // put this transaction on the pending queue...
        ent->mPendingQ.AppendElement(trans);
        NS_ADDREF(trans);
        rv = NS_OK;
    }
    else {
        rv = DispatchTransaction(ent, trans, caps, conn);
        NS_RELEASE(conn);
    }

    return rv;
}

//-----------------------------------------------------------------------------

void
nsHttpConnectionMgr::OnMsgShutdown(nsresult, void *)
{
    LOG(("nsHttpConnectionMgr::OnMsgShutdown\n"));

    mCT.Reset(ShutdownPassCB, this);

    // signal shutdown complete
    nsAutoMonitor mon(mMonitor);
    mon.Notify();
}

void
nsHttpConnectionMgr::OnMsgNewTransaction(nsresult, void *param)
{
    LOG(("nsHttpConnectionMgr::OnMsgNewTransaction [trans=%p]\n", param));

    nsHttpTransaction *trans = (nsHttpTransaction *) param;
    nsresult rv = ProcessNewTransaction(trans);
    if (NS_FAILED(rv))
        trans->Close(rv); // for whatever its worth
    NS_RELEASE(trans);
}

void
nsHttpConnectionMgr::OnMsgCancelTransaction(nsresult reason, void *param)
{
    LOG(("nsHttpConnectionMgr::OnMsgCancelTransaction [trans=%p]\n", param));

    nsHttpTransaction *trans = (nsHttpTransaction *) param;
    //
    // if the transaction owns a connection and the transaction is not done,
    // then ask the connection to close the transaction.  otherwise, close the
    // transaction directly (removing it from the pending queue first).
    //
    nsAHttpConnection *conn = trans->Connection();
    if (conn && !trans->IsDone())
        conn->CloseTransaction(trans, reason);
    else {
        nsHttpConnectionInfo *ci = trans->ConnectionInfo();
        nsCStringKey key(ci->HashKey());
        nsConnectionEntry *ent = (nsConnectionEntry *) mCT.Get(&key);
        if (ent) {
            PRInt32 index = ent->mPendingQ.IndexOf(trans);
            if (index >= 0) {
                ent->mPendingQ.RemoveElementAt(index);
                nsHttpTransaction *temp = trans;
                NS_RELEASE(temp); // b/c NS_RELEASE nulls its argument!
            }
        }
        trans->Close(reason);
    }
    NS_RELEASE(trans);
}

void
nsHttpConnectionMgr::OnMsgProcessPendingQ(nsresult, void *param)
{
    nsHttpConnectionInfo *ci = (nsHttpConnectionInfo *) param;

    LOG(("nsHttpConnectionMgr::OnMsgProcessPendingQ [ci=%s]\n", ci->HashKey().get()));

    // start by processing the queue identified by the given connection info.
    nsCStringKey key(ci->HashKey());
    nsConnectionEntry *ent = (nsConnectionEntry *) mCT.Get(&key);
    if (!(ent && ProcessPendingQForEntry(ent))) {
        // if we reach here, it means that we couldn't dispatch a transaction
        // for the specified connection info.  walk the connection table...
        mCT.Enumerate(ProcessOneTransactionCB, this);
    }

    NS_RELEASE(ci);
}

void
nsHttpConnectionMgr::OnMsgPruneDeadConnections(nsresult, void *)
{
    LOG(("nsHttpConnectionMgr::OnMsgPruneDeadConnections\n"));

    if (mNumIdleConns > 0) 
        mCT.Enumerate(PruneDeadConnectionsCB, this);
}

void
nsHttpConnectionMgr::OnMsgReclaimConnection(nsresult, void *param)
{
    LOG(("nsHttpConnectionMgr::OnMsgReclaimConnection [conn=%p]\n", param));

    nsHttpConnection *conn = (nsHttpConnection *) param;

    // 
    // 1) remove the connection from the active list
    // 2) if keep-alive, add connection to idle list
    // 3) post event to process the pending transaction queue
    //

    nsHttpConnectionInfo *ci = conn->ConnectionInfo();
    NS_ADDREF(ci);

    nsCStringKey key(ci->HashKey());
    nsConnectionEntry *ent = (nsConnectionEntry *) mCT.Get(&key);

    NS_ASSERTION(ent, "no connection entry");
    if (ent) {
        ent->mActiveConns.RemoveElement(conn);
        mNumActiveConns--;
        if (conn->CanReuse()) {
            LOG(("  adding connection to idle list\n"));
            // hold onto this connection in the idle list.  we push it to
            // the end of the list so as to ensure that we'll visit older
            // connections first before getting to this one.
            ent->mIdleConns.AppendElement(conn);
            mNumIdleConns++;
        }
        else {
            LOG(("  connection cannot be reused; closing connection\n"));
            // make sure the connection is closed and release our reference.
            conn->Close(NS_ERROR_ABORT);
            nsHttpConnection *temp = conn;
            NS_RELEASE(temp);
        }
    }
 
    OnMsgProcessPendingQ(NS_OK, ci); // releases |ci|
    NS_RELEASE(conn);
}

void
nsHttpConnectionMgr::OnMsgUpdateParam(nsresult status, void *param)
{
    PRUint16 name  = (PRUint32(param) & 0xFFFF0000) >> 16;
    PRUint16 value =  PRUint32(param) & 0x0000FFFF;

    switch (name) {
    case MAX_CONNECTIONS:
        mMaxConns = value;
        break;
    case MAX_CONNECTIONS_PER_HOST:
        mMaxConnsPerHost = value;
        break;
    case MAX_CONNECTIONS_PER_PROXY:
        mMaxConnsPerProxy = value;
        break;
    case MAX_PERSISTENT_CONNECTIONS_PER_HOST:
        mMaxPersistConnsPerHost = value;
        break;
    case MAX_PERSISTENT_CONNECTIONS_PER_PROXY:
        mMaxPersistConnsPerProxy = value;
        break;
    case MAX_REQUEST_DELAY:
        mMaxRequestDelay = value;
        break;
    case MAX_PIPELINED_REQUESTS:
        mMaxPipelinedRequests = value;
        break;
    default:
        NS_NOTREACHED("unexpected parameter name");
    }
}

//-----------------------------------------------------------------------------
// nsHttpConnectionMgr::nsConnectionHandle

nsHttpConnectionMgr::nsConnectionHandle::~nsConnectionHandle()
{
    if (mConn) {
        gHttpHandler->ReclaimConnection(mConn);
        NS_RELEASE(mConn);
    }
}

NS_IMPL_THREADSAFE_ISUPPORTS0(nsHttpConnectionMgr::nsConnectionHandle)

nsresult
nsHttpConnectionMgr::nsConnectionHandle::OnHeadersAvailable(nsAHttpTransaction *trans,
                                                            nsHttpRequestHead *req,
                                                            nsHttpResponseHead *resp,
                                                            PRBool *reset)
{
    return mConn->OnHeadersAvailable(trans, req, resp, reset);
}

nsresult
nsHttpConnectionMgr::nsConnectionHandle::ResumeSend()
{
    return mConn->ResumeSend();
}

nsresult
nsHttpConnectionMgr::nsConnectionHandle::ResumeRecv()
{
    return mConn->ResumeRecv();
}

void
nsHttpConnectionMgr::nsConnectionHandle::CloseTransaction(nsAHttpTransaction *trans, nsresult reason)
{
    mConn->CloseTransaction(trans, reason);
}

void
nsHttpConnectionMgr::nsConnectionHandle::GetConnectionInfo(nsHttpConnectionInfo **result)
{
    mConn->GetConnectionInfo(result);
}

void
nsHttpConnectionMgr::nsConnectionHandle::GetSecurityInfo(nsISupports **result)
{
    mConn->GetSecurityInfo(result);
}

PRBool
nsHttpConnectionMgr::nsConnectionHandle::IsPersistent()
{
    return mConn->IsPersistent();
}

PRBool
nsHttpConnectionMgr::nsConnectionHandle::IsReused()
{
    return mConn->IsReused();
}

nsresult
nsHttpConnectionMgr::nsConnectionHandle::PushBack(const char *buf, PRUint32 bufLen)
{
    return mConn->PushBack(buf, bufLen);
}