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 (b6057e17f856)

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
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "ImageLogging.h"
#include "nsPNGDecoder.h"

#include "nsMemory.h"
#include "nsRect.h"

#include "nsIInputStream.h"

#include "RasterImage.h"

#include "gfxColor.h"
#include "nsColor.h"

#include "nspr.h"
#include "png.h"

#include "gfxPlatform.h"
#include <algorithm>

namespace mozilla {
namespace image {

#ifdef PR_LOGGING
static PRLogModuleInfo *
GetPNGLog()
{
  static PRLogModuleInfo *sPNGLog;
  if (!sPNGLog)
    sPNGLog = PR_NewLogModule("PNGDecoder");
  return sPNGLog;
}

static PRLogModuleInfo *
GetPNGDecoderAccountingLog()
{
  static PRLogModuleInfo *sPNGDecoderAccountingLog;
  if (!sPNGDecoderAccountingLog)
    sPNGDecoderAccountingLog = PR_NewLogModule("PNGDecoderAccounting");
  return sPNGDecoderAccountingLog;
}
#endif

/* limit image dimensions (bug #251381, #591822, and #967656) */
#ifndef MOZ_PNG_MAX_DIMENSION
#  define MOZ_PNG_MAX_DIMENSION 32767
#endif

// For size decodes
#define WIDTH_OFFSET 16
#define HEIGHT_OFFSET (WIDTH_OFFSET + 4)
#define BYTES_NEEDED_FOR_DIMENSIONS (HEIGHT_OFFSET + 4)

nsPNGDecoder::AnimFrameInfo::AnimFrameInfo()
 : mDispose(FrameBlender::kDisposeKeep)
 , mBlend(FrameBlender::kBlendOver)
 , mTimeout(0)
{}

#ifdef PNG_APNG_SUPPORTED
nsPNGDecoder::AnimFrameInfo::AnimFrameInfo(png_structp aPNG, png_infop aInfo)
 : mDispose(FrameBlender::kDisposeKeep)
 , mBlend(FrameBlender::kBlendOver)
 , mTimeout(0)
{
  png_uint_16 delay_num, delay_den;
  /* delay, in seconds is delay_num/delay_den */
  png_byte dispose_op;
  png_byte blend_op;
  delay_num = png_get_next_frame_delay_num(aPNG, aInfo);
  delay_den = png_get_next_frame_delay_den(aPNG, aInfo);
  dispose_op = png_get_next_frame_dispose_op(aPNG, aInfo);
  blend_op = png_get_next_frame_blend_op(aPNG, aInfo);

  if (delay_num == 0) {
    mTimeout = 0; // SetFrameTimeout() will set to a minimum
  } else {
    if (delay_den == 0)
      delay_den = 100; // so says the APNG spec

    // Need to cast delay_num to float to have a proper division and
    // the result to int to avoid compiler warning
    mTimeout = static_cast<int32_t>(static_cast<double>(delay_num) * 1000 / delay_den);
  }

  if (dispose_op == PNG_DISPOSE_OP_PREVIOUS) {
    mDispose = FrameBlender::kDisposeRestorePrevious;
  } else if (dispose_op == PNG_DISPOSE_OP_BACKGROUND) {
    mDispose = FrameBlender::kDisposeClear;
  } else {
    mDispose = FrameBlender::kDisposeKeep;
  }

  if (blend_op == PNG_BLEND_OP_SOURCE) {
    mBlend = FrameBlender::kBlendSource;
  } else {
    mBlend = FrameBlender::kBlendOver;
  }
}
#endif

// First 8 bytes of a PNG file
const uint8_t
nsPNGDecoder::pngSignatureBytes[] = { 137, 80, 78, 71, 13, 10, 26, 10 };

nsPNGDecoder::nsPNGDecoder(RasterImage &aImage)
 : Decoder(aImage),
   mPNG(nullptr), mInfo(nullptr),
   mCMSLine(nullptr), interlacebuf(nullptr),
   mInProfile(nullptr), mTransform(nullptr),
   mHeaderBytesRead(0), mCMSMode(0),
   mChannels(0), mFrameIsHidden(false),
   mDisablePremultipliedAlpha(false),
   mNumFrames(0)
{
}

nsPNGDecoder::~nsPNGDecoder()
{
  if (mPNG)
    png_destroy_read_struct(&mPNG, mInfo ? &mInfo : nullptr, nullptr);
  if (mCMSLine)
    nsMemory::Free(mCMSLine);
  if (interlacebuf)
    nsMemory::Free(interlacebuf);
  if (mInProfile) {
    qcms_profile_release(mInProfile);

    /* mTransform belongs to us only if mInProfile is non-null */
    if (mTransform)
      qcms_transform_release(mTransform);
  }
}

// CreateFrame() is used for both simple and animated images
void nsPNGDecoder::CreateFrame(png_uint_32 x_offset, png_uint_32 y_offset,
                               int32_t width, int32_t height,
                               gfx::SurfaceFormat format)
{
  // Our first full frame is automatically created by the image decoding
  // infrastructure. Just use it as long as it matches up.
  MOZ_ASSERT(HasSize());
  if (mNumFrames != 0 ||
      !GetCurrentFrame()->GetRect().IsEqualEdges(nsIntRect(x_offset, y_offset, width, height))) {
    NeedNewFrame(mNumFrames, x_offset, y_offset, width, height, format);
  } else if (mNumFrames == 0) {
    // Our preallocated frame matches up, with the possible exception of alpha.
    if (format == gfx::SurfaceFormat::B8G8R8X8) {
      GetCurrentFrame()->SetHasNoAlpha();
    }
  }

  mFrameRect.x = x_offset;
  mFrameRect.y = y_offset;
  mFrameRect.width = width;
  mFrameRect.height = height;

  PR_LOG(GetPNGDecoderAccountingLog(), PR_LOG_DEBUG,
         ("PNGDecoderAccounting: nsPNGDecoder::CreateFrame -- created "
          "image frame with %dx%d pixels in container %p",
          width, height,
          &mImage));

  mFrameHasNoAlpha = true;

#ifdef PNG_APNG_SUPPORTED
  if (png_get_valid(mPNG, mInfo, PNG_INFO_acTL)) {
    mAnimInfo = AnimFrameInfo(mPNG, mInfo);
  }
#endif
}

// set timeout and frame disposal method for the current frame
void nsPNGDecoder::EndImageFrame()
{
  if (mFrameIsHidden)
    return;

  mNumFrames++;

  FrameBlender::FrameAlpha alpha;
  if (mFrameHasNoAlpha)
    alpha = FrameBlender::kFrameOpaque;
  else
    alpha = FrameBlender::kFrameHasAlpha;

#ifdef PNG_APNG_SUPPORTED
  uint32_t numFrames = GetFrameCount();

  // We can't use mPNG->num_frames_read as it may be one ahead.
  if (numFrames > 1) {
    PostInvalidation(mFrameRect);
  }
#endif

  PostFrameStop(alpha, mAnimInfo.mDispose, mAnimInfo.mTimeout, mAnimInfo.mBlend);
}

void
nsPNGDecoder::InitInternal()
{
  // For size decodes, we don't need to initialize the png decoder
  if (IsSizeDecode()) {
    return;
  }

  mCMSMode = gfxPlatform::GetCMSMode();
  if ((mDecodeFlags & DECODER_NO_COLORSPACE_CONVERSION) != 0)
    mCMSMode = eCMSMode_Off;
  mDisablePremultipliedAlpha = (mDecodeFlags & DECODER_NO_PREMULTIPLY_ALPHA) != 0;

#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
  static png_byte color_chunks[]=
       { 99,  72,  82,  77, '\0',   /* cHRM */
        105,  67,  67,  80, '\0'};  /* iCCP */
  static png_byte unused_chunks[]=
       { 98,  75,  71,  68, '\0',   /* bKGD */
        104,  73,  83,  84, '\0',   /* hIST */
        105,  84,  88, 116, '\0',   /* iTXt */
        111,  70,  70, 115, '\0',   /* oFFs */
        112,  67,  65,  76, '\0',   /* pCAL */
        115,  67,  65,  76, '\0',   /* sCAL */
        112,  72,  89, 115, '\0',   /* pHYs */
        115,  66,  73,  84, '\0',   /* sBIT */
        115,  80,  76,  84, '\0',   /* sPLT */
        116,  69,  88, 116, '\0',   /* tEXt */
        116,  73,  77,  69, '\0',   /* tIME */
        122,  84,  88, 116, '\0'};  /* zTXt */
#endif

  /* For full decodes, do png init stuff */

  /* Initialize the container's source image header. */
  /* Always decode to 24 bit pixdepth */

  mPNG = png_create_read_struct(PNG_LIBPNG_VER_STRING,
                                nullptr, nsPNGDecoder::error_callback,
                                nsPNGDecoder::warning_callback);
  if (!mPNG) {
    PostDecoderError(NS_ERROR_OUT_OF_MEMORY);
    return;
  }

  mInfo = png_create_info_struct(mPNG);
  if (!mInfo) {
    PostDecoderError(NS_ERROR_OUT_OF_MEMORY);
    png_destroy_read_struct(&mPNG, nullptr, nullptr);
    return;
  }

#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
  /* Ignore unused chunks */
  if (mCMSMode == eCMSMode_Off)
    png_set_keep_unknown_chunks(mPNG, 1, color_chunks, 2);

  png_set_keep_unknown_chunks(mPNG, 1, unused_chunks,
                              (int)sizeof(unused_chunks)/5);
#endif

#ifdef PNG_SET_CHUNK_MALLOC_LIMIT_SUPPORTED
  if (mCMSMode != eCMSMode_Off)
    png_set_chunk_malloc_max(mPNG, 4000000L);
#endif

#ifdef PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED
#ifndef PR_LOGGING
  /* Disallow palette-index checking, for speed; we would ignore the warning
   * anyhow unless we have defined PR_LOGGING.  This feature was added at
   * libpng version 1.5.10 and is disabled in the embedded libpng but enabled
   * by default in the system libpng.  This call also disables it in the
   * system libpng, for decoding speed.  Bug #745202.
   */
    png_set_check_for_invalid_index(mPNG, 0);
#endif
#endif

  /* use this as libpng "progressive pointer" (retrieve in callbacks) */
  png_set_progressive_read_fn(mPNG, static_cast<png_voidp>(this),
                              nsPNGDecoder::info_callback,
                              nsPNGDecoder::row_callback,
                              nsPNGDecoder::end_callback);

}

void
nsPNGDecoder::WriteInternal(const char *aBuffer, uint32_t aCount, DecodeStrategy)
{
  NS_ABORT_IF_FALSE(!HasError(), "Shouldn't call WriteInternal after error!");

  // If we only want width/height, we don't need to go through libpng
  if (IsSizeDecode()) {

    // Are we done?
    if (mHeaderBytesRead == BYTES_NEEDED_FOR_DIMENSIONS)
      return;

    // Scan the header for the width and height bytes
    uint32_t pos = 0;
    const uint8_t *bptr = (uint8_t *)aBuffer;

    while (pos < aCount && mHeaderBytesRead < BYTES_NEEDED_FOR_DIMENSIONS) {
      // Verify the signature bytes
      if (mHeaderBytesRead < sizeof(pngSignatureBytes)) {
        if (bptr[pos] != nsPNGDecoder::pngSignatureBytes[mHeaderBytesRead]) {
          PostDataError();
          return;
        }
      }

      // Get width and height bytes into the buffer
      if ((mHeaderBytesRead >= WIDTH_OFFSET) &&
          (mHeaderBytesRead < BYTES_NEEDED_FOR_DIMENSIONS)) {
        mSizeBytes[mHeaderBytesRead - WIDTH_OFFSET] = bptr[pos];
      }
      pos ++;
      mHeaderBytesRead ++;
    }

    // If we're done now, verify the data and set up the container
    if (mHeaderBytesRead == BYTES_NEEDED_FOR_DIMENSIONS) {

      // Grab the width and height, accounting for endianness (thanks libpng!)
      uint32_t width = png_get_uint_32(mSizeBytes);
      uint32_t height = png_get_uint_32(mSizeBytes + 4);

      // Too big?
      if ((width > MOZ_PNG_MAX_DIMENSION) || (height > MOZ_PNG_MAX_DIMENSION)) {
        PostDataError();
        return;
      }

      // Post our size to the superclass
      PostSize(width, height);
    }
  }

  // Otherwise, we're doing a standard decode
  else {

    // libpng uses setjmp/longjmp for error handling - set the buffer
    if (setjmp(png_jmpbuf(mPNG))) {

      // We might not really know what caused the error, but it makes more
      // sense to blame the data.
      if (!HasError())
        PostDataError();

      png_destroy_read_struct(&mPNG, &mInfo, nullptr);
      return;
    }

    // Pass the data off to libpng
    png_process_data(mPNG, mInfo, (unsigned char *)aBuffer, aCount);

  }
}

// Sets up gamma pre-correction in libpng before our callback gets called.
// We need to do this if we don't end up with a CMS profile.
static void
PNGDoGammaCorrection(png_structp png_ptr, png_infop info_ptr)
{
  double aGamma;

  if (png_get_gAMA(png_ptr, info_ptr, &aGamma)) {
    if ((aGamma <= 0.0) || (aGamma > 21474.83)) {
      aGamma = 0.45455;
      png_set_gAMA(png_ptr, info_ptr, aGamma);
    }
    png_set_gamma(png_ptr, 2.2, aGamma);
  }
  else
    png_set_gamma(png_ptr, 2.2, 0.45455);

}

// Adapted from http://www.littlecms.com/pngchrm.c example code
static qcms_profile *
PNGGetColorProfile(png_structp png_ptr, png_infop info_ptr,
                   int color_type, qcms_data_type *inType, uint32_t *intent)
{
  qcms_profile *profile = nullptr;
  *intent = QCMS_INTENT_PERCEPTUAL; // Our default

  // First try to see if iCCP chunk is present
  if (png_get_valid(png_ptr, info_ptr, PNG_INFO_iCCP)) {
    png_uint_32 profileLen;
#if (PNG_LIBPNG_VER < 10500)
    char *profileData, *profileName;
#else
    png_bytep profileData;
    png_charp profileName;
#endif
    int compression;

    png_get_iCCP(png_ptr, info_ptr, &profileName, &compression,
                 &profileData, &profileLen);

    profile = qcms_profile_from_memory(
#if (PNG_LIBPNG_VER < 10500)
                                       profileData,
#else
                                       (char *)profileData,
#endif
                                       profileLen);
    if (profile) {
      uint32_t profileSpace = qcms_profile_get_color_space(profile);

      bool mismatch = false;
      if (color_type & PNG_COLOR_MASK_COLOR) {
        if (profileSpace != icSigRgbData)
          mismatch = true;
      } else {
        if (profileSpace == icSigRgbData)
          png_set_gray_to_rgb(png_ptr);
        else if (profileSpace != icSigGrayData)
          mismatch = true;
      }

      if (mismatch) {
        qcms_profile_release(profile);
        profile = nullptr;
      } else {
        *intent = qcms_profile_get_rendering_intent(profile);
      }
    }
  }

  // Check sRGB chunk
  if (!profile && png_get_valid(png_ptr, info_ptr, PNG_INFO_sRGB)) {
    profile = qcms_profile_sRGB();

    if (profile) {
      int fileIntent;
      png_set_gray_to_rgb(png_ptr);
      png_get_sRGB(png_ptr, info_ptr, &fileIntent);
      uint32_t map[] = { QCMS_INTENT_PERCEPTUAL,
                         QCMS_INTENT_RELATIVE_COLORIMETRIC,
                         QCMS_INTENT_SATURATION,
                         QCMS_INTENT_ABSOLUTE_COLORIMETRIC };
      *intent = map[fileIntent];
    }
  }

  // Check gAMA/cHRM chunks
  if (!profile &&
       png_get_valid(png_ptr, info_ptr, PNG_INFO_gAMA) &&
       png_get_valid(png_ptr, info_ptr, PNG_INFO_cHRM)) {
    qcms_CIE_xyYTRIPLE primaries;
    qcms_CIE_xyY whitePoint;

    png_get_cHRM(png_ptr, info_ptr,
                 &whitePoint.x, &whitePoint.y,
                 &primaries.red.x,   &primaries.red.y,
                 &primaries.green.x, &primaries.green.y,
                 &primaries.blue.x,  &primaries.blue.y);
    whitePoint.Y =
      primaries.red.Y = primaries.green.Y = primaries.blue.Y = 1.0;

    double gammaOfFile;

    png_get_gAMA(png_ptr, info_ptr, &gammaOfFile);

    profile = qcms_profile_create_rgb_with_gamma(whitePoint, primaries,
                                                 1.0/gammaOfFile);

    if (profile)
      png_set_gray_to_rgb(png_ptr);
  }

  if (profile) {
    uint32_t profileSpace = qcms_profile_get_color_space(profile);
    if (profileSpace == icSigGrayData) {
      if (color_type & PNG_COLOR_MASK_ALPHA)
        *inType = QCMS_DATA_GRAYA_8;
      else
        *inType = QCMS_DATA_GRAY_8;
    } else {
      if (color_type & PNG_COLOR_MASK_ALPHA ||
          png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS))
        *inType = QCMS_DATA_RGBA_8;
      else
        *inType = QCMS_DATA_RGB_8;
    }
  }

  return profile;
}

void
nsPNGDecoder::info_callback(png_structp png_ptr, png_infop info_ptr)
{
/*  int number_passes;   NOT USED  */
  png_uint_32 width, height;
  int bit_depth, color_type, interlace_type, compression_type, filter_type;
  unsigned int channels;

  png_bytep trans = nullptr;
  int num_trans = 0;

  nsPNGDecoder *decoder =
               static_cast<nsPNGDecoder*>(png_get_progressive_ptr(png_ptr));

  /* always decode to 24-bit RGB or 32-bit RGBA  */
  png_get_IHDR(png_ptr, info_ptr, &width, &height, &bit_depth, &color_type,
               &interlace_type, &compression_type, &filter_type);

  /* Are we too big? */
  if (width > MOZ_PNG_MAX_DIMENSION || height > MOZ_PNG_MAX_DIMENSION)
    longjmp(png_jmpbuf(decoder->mPNG), 1);

  // Post our size to the superclass
  decoder->PostSize(width, height);
  if (decoder->HasError()) {
    // Setting the size led to an error.
    longjmp(png_jmpbuf(decoder->mPNG), 1);
  }

  if (color_type == PNG_COLOR_TYPE_PALETTE)
    png_set_expand(png_ptr);

  if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8)
    png_set_expand(png_ptr);

  if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)) {
    png_color_16p trans_values;
    png_get_tRNS(png_ptr, info_ptr, &trans, &num_trans, &trans_values);
    /* libpng doesn't reject a tRNS chunk with out-of-range samples
       so we check it here to avoid setting up a useless opacity
       channel or producing unexpected transparent pixels (bug #428045) */
    if (bit_depth < 16) {
      png_uint_16 sample_max = (1 << bit_depth) - 1;
      if ((color_type == PNG_COLOR_TYPE_GRAY &&
           trans_values->gray > sample_max) ||
           (color_type == PNG_COLOR_TYPE_RGB &&
           (trans_values->red > sample_max ||
           trans_values->green > sample_max ||
           trans_values->blue > sample_max)))
      {
        /* clear the tRNS valid flag and release tRNS memory */
        png_free_data(png_ptr, info_ptr, PNG_FREE_TRNS, 0);
        num_trans = 0;
      }
    }
    if (num_trans != 0)
      png_set_expand(png_ptr);
  }

  if (bit_depth == 16)
    png_set_scale_16(png_ptr);

  qcms_data_type inType = QCMS_DATA_RGBA_8;
  uint32_t intent = -1;
  uint32_t pIntent;
  if (decoder->mCMSMode != eCMSMode_Off) {
    intent = gfxPlatform::GetRenderingIntent();
    decoder->mInProfile = PNGGetColorProfile(png_ptr, info_ptr,
                                             color_type, &inType, &pIntent);
    /* If we're not mandating an intent, use the one from the image. */
    if (intent == uint32_t(-1))
      intent = pIntent;
  }
  if (decoder->mInProfile && gfxPlatform::GetCMSOutputProfile()) {
    qcms_data_type outType;

    if (color_type & PNG_COLOR_MASK_ALPHA || num_trans)
      outType = QCMS_DATA_RGBA_8;
    else
      outType = QCMS_DATA_RGB_8;

    decoder->mTransform = qcms_transform_create(decoder->mInProfile,
                                           inType,
                                           gfxPlatform::GetCMSOutputProfile(),
                                           outType,
                                           (qcms_intent)intent);
  } else {
    png_set_gray_to_rgb(png_ptr);

    // only do gamma correction if CMS isn't entirely disabled
    if (decoder->mCMSMode != eCMSMode_Off)
      PNGDoGammaCorrection(png_ptr, info_ptr);

    if (decoder->mCMSMode == eCMSMode_All) {
      if (color_type & PNG_COLOR_MASK_ALPHA || num_trans)
        decoder->mTransform = gfxPlatform::GetCMSRGBATransform();
      else
        decoder->mTransform = gfxPlatform::GetCMSRGBTransform();
    }
  }

  /* let libpng expand interlaced images */
  if (interlace_type == PNG_INTERLACE_ADAM7) {
    /* number_passes = */
    png_set_interlace_handling(png_ptr);
  }

  /* now all of those things we set above are used to update various struct
   * members and whatnot, after which we can get channels, rowbytes, etc. */
  png_read_update_info(png_ptr, info_ptr);
  decoder->mChannels = channels = png_get_channels(png_ptr, info_ptr);

  /*---------------------------------------------------------------*/
  /* copy PNG info into imagelib structs (formerly png_set_dims()) */
  /*---------------------------------------------------------------*/

  // This code is currently unused, but it will be needed for bug 517713.
#if 0
  int32_t alpha_bits = 1;

  if (channels == 2 || channels == 4) {
    /* check if alpha is coming from a tRNS chunk and is binary */
    if (num_trans) {
      /* if it's not an indexed color image, tRNS means binary */
      if (color_type == PNG_COLOR_TYPE_PALETTE) {
        for (int i=0; i<num_trans; i++) {
          if ((trans[i] != 0) && (trans[i] != 255)) {
            alpha_bits = 8;
            break;
          }
        }
      }
    } else {
      alpha_bits = 8;
    }
  }
#endif

  if (channels == 1 || channels == 3)
    decoder->format = gfx::SurfaceFormat::B8G8R8X8;
  else if (channels == 2 || channels == 4)
    decoder->format = gfx::SurfaceFormat::B8G8R8A8;

#ifdef PNG_APNG_SUPPORTED
  if (png_get_valid(png_ptr, info_ptr, PNG_INFO_acTL))
    png_set_progressive_frame_fn(png_ptr, nsPNGDecoder::frame_info_callback,
                                 nullptr);

  if (png_get_first_frame_is_hidden(png_ptr, info_ptr)) {
    decoder->mFrameIsHidden = true;
  } else {
#endif
    decoder->CreateFrame(0, 0, width, height, decoder->format);
#ifdef PNG_APNG_SUPPORTED
  }
#endif

  if (decoder->mTransform &&
      (channels <= 2 || interlace_type == PNG_INTERLACE_ADAM7)) {
    uint32_t bpp[] = { 0, 3, 4, 3, 4 };
    decoder->mCMSLine =
      (uint8_t *)moz_malloc(bpp[channels] * width);
    if (!decoder->mCMSLine) {
      longjmp(png_jmpbuf(decoder->mPNG), 5); // NS_ERROR_OUT_OF_MEMORY
    }
  }

  if (interlace_type == PNG_INTERLACE_ADAM7) {
    if (height < INT32_MAX / (width * channels))
      decoder->interlacebuf = (uint8_t *)moz_malloc(channels * width * height);
    if (!decoder->interlacebuf) {
      longjmp(png_jmpbuf(decoder->mPNG), 5); // NS_ERROR_OUT_OF_MEMORY
    }
  }

  if (decoder->NeedsNewFrame()) {
    /* We know that we need a new frame, so pause input so the decoder
     * infrastructure can give it to us.
     */
    png_process_data_pause(png_ptr, /* save = */ 1);
  }
}

void
nsPNGDecoder::row_callback(png_structp png_ptr, png_bytep new_row,
                           png_uint_32 row_num, int pass)
{
  /* libpng comments:
   *
   * this function is called for every row in the image.  If the
   * image is interlacing, and you turned on the interlace handler,
   * this function will be called for every row in every pass.
   * Some of these rows will not be changed from the previous pass.
   * When the row is not changed, the new_row variable will be
   * nullptr. The rows and passes are called in order, so you don't
   * really need the row_num and pass, but I'm supplying them
   * because it may make your life easier.
   *
   * For the non-nullptr rows of interlaced images, you must call
   * png_progressive_combine_row() passing in the row and the
   * old row.  You can call this function for nullptr rows (it will
   * just return) and for non-interlaced images (it just does the
   * memcpy for you) if it will make the code easier.  Thus, you
   * can just do this for all cases:
   *
   *    png_progressive_combine_row(png_ptr, old_row, new_row);
   *
   * where old_row is what was displayed for previous rows.  Note
   * that the first pass (pass == 0 really) will completely cover
   * the old row, so the rows do not have to be initialized.  After
   * the first pass (and only for interlaced images), you will have
   * to pass the current row, and the function will combine the
   * old row and the new row.
   */
  nsPNGDecoder *decoder =
               static_cast<nsPNGDecoder*>(png_get_progressive_ptr(png_ptr));

  // skip this frame
  if (decoder->mFrameIsHidden)
    return;

  if (row_num >= (png_uint_32) decoder->mFrameRect.height)
    return;

  if (new_row) {
    int32_t width = decoder->mFrameRect.width;
    uint32_t iwidth = decoder->mFrameRect.width;

    png_bytep line = new_row;
    if (decoder->interlacebuf) {
      line = decoder->interlacebuf + (row_num * decoder->mChannels * width);
      png_progressive_combine_row(png_ptr, line, new_row);
    }

    uint32_t bpr = width * sizeof(uint32_t);
    uint32_t *cptr32 = (uint32_t*)(decoder->mImageData + (row_num*bpr));
    bool rowHasNoAlpha = true;

    if (decoder->mTransform) {
      if (decoder->mCMSLine) {
        qcms_transform_data(decoder->mTransform, line, decoder->mCMSLine,
                            iwidth);
        /* copy alpha over */
        uint32_t channels = decoder->mChannels;
        if (channels == 2 || channels == 4) {
          for (uint32_t i = 0; i < iwidth; i++)
            decoder->mCMSLine[4 * i + 3] = line[channels * i + channels - 1];
        }
        line = decoder->mCMSLine;
      } else {
        qcms_transform_data(decoder->mTransform, line, line, iwidth);
       }
     }

    switch (decoder->format) {
      case gfx::SurfaceFormat::B8G8R8X8:
      {
        // counter for while() loops below
        uint32_t idx = iwidth;

        // copy as bytes until source pointer is 32-bit-aligned
        for (; (NS_PTR_TO_UINT32(line) & 0x3) && idx; --idx) {
          *cptr32++ = gfxPackedPixel(0xFF, line[0], line[1], line[2]);
          line += 3;
        }

        // copy pixels in blocks of 4
        while (idx >= 4) {
          GFX_BLOCK_RGB_TO_FRGB(line, cptr32);
          idx    -=  4;
          line   += 12;
          cptr32 +=  4;
        }

        // copy remaining pixel(s)
        while (idx--) {
          // 32-bit read of final pixel will exceed buffer, so read bytes
          *cptr32++ = gfxPackedPixel(0xFF, line[0], line[1], line[2]);
          line += 3;
        }
      }
      break;
      case gfx::SurfaceFormat::B8G8R8A8:
      {
        if (!decoder->mDisablePremultipliedAlpha) {
          for (uint32_t x=width; x>0; --x) {
            *cptr32++ = gfxPackedPixel(line[3], line[0], line[1], line[2]);
            if (line[3] != 0xff)
              rowHasNoAlpha = false;
            line += 4;
          }
        } else {
          for (uint32_t x=width; x>0; --x) {
            *cptr32++ = gfxPackedPixelNoPreMultiply(line[3], line[0], line[1], line[2]);
            if (line[3] != 0xff)
              rowHasNoAlpha = false;
            line += 4;
          }
        }
      }
      break;
      default:
        longjmp(png_jmpbuf(decoder->mPNG), 1);
    }

    if (!rowHasNoAlpha)
      decoder->mFrameHasNoAlpha = false;

    if (decoder->mNumFrames <= 1) {
      // Only do incremental image display for the first frame
      // XXXbholley - this check should be handled in the superclass
      nsIntRect r(0, row_num, width, 1);
      decoder->PostInvalidation(r);
    }
  }
}

#ifdef PNG_APNG_SUPPORTED
// got the header of a new frame that's coming
void
nsPNGDecoder::frame_info_callback(png_structp png_ptr, png_uint_32 frame_num)
{
  png_uint_32 x_offset, y_offset;
  int32_t width, height;

  nsPNGDecoder *decoder =
               static_cast<nsPNGDecoder*>(png_get_progressive_ptr(png_ptr));

  // old frame is done
  decoder->EndImageFrame();

  // Only the first frame can be hidden, so unhide unconditionally here.
  decoder->mFrameIsHidden = false;

  x_offset = png_get_next_frame_x_offset(png_ptr, decoder->mInfo);
  y_offset = png_get_next_frame_y_offset(png_ptr, decoder->mInfo);
  width = png_get_next_frame_width(png_ptr, decoder->mInfo);
  height = png_get_next_frame_height(png_ptr, decoder->mInfo);

  decoder->CreateFrame(x_offset, y_offset, width, height, decoder->format);

  if (decoder->NeedsNewFrame()) {
    /* We know that we need a new frame, so pause input so the decoder
     * infrastructure can give it to us.
     */
    png_process_data_pause(png_ptr, /* save = */ 1);
  }
}
#endif

void
nsPNGDecoder::end_callback(png_structp png_ptr, png_infop info_ptr)
{
  /* libpng comments:
   *
   * this function is called when the whole image has been read,
   * including any chunks after the image (up to and including
   * the IEND).  You will usually have the same info chunk as you
   * had in the header, although some data may have been added
   * to the comments and time fields.
   *
   * Most people won't do much here, perhaps setting a flag that
   * marks the image as finished.
   */

  nsPNGDecoder *decoder =
               static_cast<nsPNGDecoder*>(png_get_progressive_ptr(png_ptr));

  // We shouldn't get here if we've hit an error
  NS_ABORT_IF_FALSE(!decoder->HasError(), "Finishing up PNG but hit error!");

  int32_t loop_count = 0;
#ifdef PNG_APNG_SUPPORTED
  if (png_get_valid(png_ptr, info_ptr, PNG_INFO_acTL)) {
    int32_t num_plays = png_get_num_plays(png_ptr, info_ptr);
    loop_count = num_plays - 1;
  }
#endif

  // Send final notifications
  decoder->EndImageFrame();
  decoder->PostDecodeDone(loop_count);
}


void
nsPNGDecoder::error_callback(png_structp png_ptr, png_const_charp error_msg)
{
  PR_LOG(GetPNGLog(), PR_LOG_ERROR, ("libpng error: %s\n", error_msg));
  longjmp(png_jmpbuf(png_ptr), 1);
}


void
nsPNGDecoder::warning_callback(png_structp png_ptr, png_const_charp warning_msg)
{
  PR_LOG(GetPNGLog(), PR_LOG_WARNING, ("libpng warning: %s\n", warning_msg));
}

Telemetry::ID
nsPNGDecoder::SpeedHistogram()
{
  return Telemetry::IMAGE_DECODE_SPEED_PNG;
}


} // namespace image
} // namespace mozilla