image/decoders/nsPNGDecoder.cpp

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
   2  *
   3  * This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "ImageLogging.h"  // Must appear first
   8 #include "nsPNGDecoder.h"
   9
  10 #include <algorithm>
  11 #include <cstdint>
  12
  13 #include "gfxColor.h"
  14 #include "gfxPlatform.h"
  15 #include "imgFrame.h"
  16 #include "nsColor.h"
  17 #include "nsMemory.h"
  18 #include "nsRect.h"
  19 #include "nspr.h"
  20 #include "png.h"
  21
  22 #include "RasterImage.h"
  23 #include "SurfaceCache.h"
  24 #include "SurfacePipeFactory.h"
  25 #include "mozilla/DebugOnly.h"
  26 #include "mozilla/Telemetry.h"
  27
  28 using namespace mozilla::gfx;
  29
  30 using std::min;
  31
  32 namespace mozilla {
  33 namespace image {
  34
  35 static LazyLogModule sPNGLog("PNGDecoder");
  36 static LazyLogModule sPNGDecoderAccountingLog("PNGDecoderAccounting");
  37
  38 // limit image dimensions (bug #251381, #591822, #967656, and #1283961)
  39 #ifndef MOZ_PNG_MAX_WIDTH
  40 #  define MOZ_PNG_MAX_WIDTH 0x7fffffff  // Unlimited
  41 #endif
  42 #ifndef MOZ_PNG_MAX_HEIGHT
  43 #  define MOZ_PNG_MAX_HEIGHT 0x7fffffff  // Unlimited
  44 #endif
  45
  46 /* Controls the maximum chunk size configuration for libpng. We set this to a
  47  * very large number, 256MB specifically. */
  48 static constexpr png_alloc_size_t kPngMaxChunkSize = 0x10000000;
  49
  50 nsPNGDecoder::AnimFrameInfo::AnimFrameInfo()
  51     : mDispose(DisposalMethod::KEEP), mBlend(BlendMethod::OVER), mTimeout(0) {}
  52
  53 #ifdef PNG_APNG_SUPPORTED
  54
  55 int32_t GetNextFrameDelay(png_structp aPNG, png_infop aInfo) {
  56   // Delay, in seconds, is delayNum / delayDen.
  57   png_uint_16 delayNum = png_get_next_frame_delay_num(aPNG, aInfo);
  58   png_uint_16 delayDen = png_get_next_frame_delay_den(aPNG, aInfo);
  59
  60   if (delayNum == 0) {
  61     return 0;  // SetFrameTimeout() will set to a minimum.
  62   }
  63
  64   if (delayDen == 0) {
  65     delayDen = 100;  // So says the APNG spec.
  66   }
  67
  68   // Need to cast delay_num to float to have a proper division and
  69   // the result to int to avoid a compiler warning.
  70   return static_cast<int32_t>(static_cast<double>(delayNum) * 1000 / delayDen);
  71 }
  72
  73 nsPNGDecoder::AnimFrameInfo::AnimFrameInfo(png_structp aPNG, png_infop aInfo)
  74     : mDispose(DisposalMethod::KEEP), mBlend(BlendMethod::OVER), mTimeout(0) {
  75   png_byte dispose_op = png_get_next_frame_dispose_op(aPNG, aInfo);
  76   png_byte blend_op = png_get_next_frame_blend_op(aPNG, aInfo);
  77
  78   if (dispose_op == PNG_DISPOSE_OP_PREVIOUS) {
  79     mDispose = DisposalMethod::RESTORE_PREVIOUS;
  80   } else if (dispose_op == PNG_DISPOSE_OP_BACKGROUND) {
  81     mDispose = DisposalMethod::CLEAR;
  82   } else {
  83     mDispose = DisposalMethod::KEEP;
  84   }
  85
  86   if (blend_op == PNG_BLEND_OP_SOURCE) {
  87     mBlend = BlendMethod::SOURCE;
  88   } else {
  89     mBlend = BlendMethod::OVER;
  90   }
  91
  92   mTimeout = GetNextFrameDelay(aPNG, aInfo);
  93 }
  94 #endif
  95
  96 // First 8 bytes of a PNG file
  97 const uint8_t nsPNGDecoder::pngSignatureBytes[] = {137, 80, 78, 71,
  98                                                    13,  10, 26, 10};
  99
 100 nsPNGDecoder::nsPNGDecoder(RasterImage* aImage)
 101     : Decoder(aImage),
 102       mLexer(Transition::ToUnbuffered(State::FINISHED_PNG_DATA, State::PNG_DATA,
 103                                       SIZE_MAX),
 104              Transition::TerminateSuccess()),
 105       mNextTransition(Transition::ContinueUnbuffered(State::PNG_DATA)),
 106       mLastChunkLength(0),
 107       mPNG(nullptr),
 108       mInfo(nullptr),
 109       mCMSLine(nullptr),
 110       interlacebuf(nullptr),
 111       mFormat(SurfaceFormat::UNKNOWN),
 112       mChannels(0),
 113       mPass(0),
 114       mFrameIsHidden(false),
 115       mDisablePremultipliedAlpha(false),
 116       mGotInfoCallback(false),
 117       mUsePipeTransform(false),
 118       mNumFrames(0) {}
 119
 120 nsPNGDecoder::~nsPNGDecoder() {
 121   if (mPNG) {
 122     png_destroy_read_struct(&mPNG, mInfo ? &mInfo : nullptr, nullptr);
 123   }
 124   if (mCMSLine) {
 125     free(mCMSLine);
 126   }
 127   if (interlacebuf) {
 128     free(interlacebuf);
 129   }
 130 }
 131
 132 nsPNGDecoder::TransparencyType nsPNGDecoder::GetTransparencyType(
 133     const IntRect& aFrameRect) {
 134   // Check if the image has a transparent color in its palette.
 135   if (HasAlphaChannel()) {
 136     return TransparencyType::eAlpha;
 137   }
 138   if (!aFrameRect.IsEqualEdges(FullFrame())) {
 139     MOZ_ASSERT(HasAnimation());
 140     return TransparencyType::eFrameRect;
 141   }
 142
 143   return TransparencyType::eNone;
 144 }
 145
 146 void nsPNGDecoder::PostHasTransparencyIfNeeded(
 147     TransparencyType aTransparencyType) {
 148   switch (aTransparencyType) {
 149     case TransparencyType::eNone:
 150       return;
 151
 152     case TransparencyType::eAlpha:
 153       PostHasTransparency();
 154       return;
 155
 156     case TransparencyType::eFrameRect:
 157       // If the first frame of animated image doesn't draw into the whole image,
 158       // then record that it is transparent. For subsequent frames, this doesn't
 159       // affect transparency, because they're composited on top of all previous
 160       // frames.
 161       if (mNumFrames == 0) {
 162         PostHasTransparency();
 163       }
 164       return;
 165   }
 166 }
 167
 168 // CreateFrame() is used for both simple and animated images.
 169 nsresult nsPNGDecoder::CreateFrame(const FrameInfo& aFrameInfo) {
 170   MOZ_ASSERT(HasSize());
 171   MOZ_ASSERT(!IsMetadataDecode());
 172
 173   // Check if we have transparency, and send notifications if needed.
 174   auto transparency = GetTransparencyType(aFrameInfo.mFrameRect);
 175   PostHasTransparencyIfNeeded(transparency);
 176   mFormat = transparency == TransparencyType::eNone ? SurfaceFormat::OS_RGBX
 177                                                     : SurfaceFormat::OS_RGBA;
 178
 179   // Make sure there's no animation or padding if we're downscaling.
 180   MOZ_ASSERT_IF(Size() != OutputSize(), mNumFrames == 0);
 181   MOZ_ASSERT_IF(Size() != OutputSize(), !GetImageMetadata().HasAnimation());
 182   MOZ_ASSERT_IF(Size() != OutputSize(),
 183                 transparency != TransparencyType::eFrameRect);
 184
 185   Maybe<AnimationParams> animParams;
 186 #ifdef PNG_APNG_SUPPORTED
 187   if (!IsFirstFrameDecode() && png_get_valid(mPNG, mInfo, PNG_INFO_acTL)) {
 188     mAnimInfo = AnimFrameInfo(mPNG, mInfo);
 189
 190     if (mAnimInfo.mDispose == DisposalMethod::CLEAR) {
 191       // We may have to display the background under this image during
 192       // animation playback, so we regard it as transparent.
 193       PostHasTransparency();
 194     }
 195
 196     animParams.emplace(
 197         AnimationParams{aFrameInfo.mFrameRect,
 198                         FrameTimeout::FromRawMilliseconds(mAnimInfo.mTimeout),
 199                         mNumFrames, mAnimInfo.mBlend, mAnimInfo.mDispose});
 200   }
 201 #endif
 202
 203   // If this image is interlaced, we can display better quality intermediate
 204   // results to the user by post processing them with ADAM7InterpolatingFilter.
 205   SurfacePipeFlags pipeFlags = aFrameInfo.mIsInterlaced
 206                                    ? SurfacePipeFlags::ADAM7_INTERPOLATE
 207                                    : SurfacePipeFlags();
 208
 209   if (mNumFrames == 0) {
 210     // The first frame may be displayed progressively.
 211     pipeFlags |= SurfacePipeFlags::PROGRESSIVE_DISPLAY;
 212   }
 213
 214   SurfaceFormat inFormat;
 215   if (mTransform && !mUsePipeTransform) {
 216     // QCMS will output in the correct format.
 217     inFormat = mFormat;
 218   } else if (transparency == TransparencyType::eAlpha) {
 219     // We are outputting directly as RGBA, so we need to swap at this step.
 220     inFormat = SurfaceFormat::R8G8B8A8;
 221   } else {
 222     // We have no alpha channel, so we need to unpack from RGB to BGRA.
 223     inFormat = SurfaceFormat::R8G8B8;
 224   }
 225
 226   // Only apply premultiplication if the frame has true alpha. If we ever
 227   // support downscaling animated images, we will need to premultiply for frame
 228   // rect transparency when downscaling as well.
 229   if (transparency == TransparencyType::eAlpha && !mDisablePremultipliedAlpha) {
 230     pipeFlags |= SurfacePipeFlags::PREMULTIPLY_ALPHA;
 231   }
 232
 233   qcms_transform* pipeTransform = mUsePipeTransform ? mTransform : nullptr;
 234   Maybe<SurfacePipe> pipe = SurfacePipeFactory::CreateSurfacePipe(
 235       this, Size(), OutputSize(), aFrameInfo.mFrameRect, inFormat, mFormat,
 236       animParams, pipeTransform, pipeFlags);
 237
 238   if (!pipe) {
 239     mPipe = SurfacePipe();
 240     return NS_ERROR_FAILURE;
 241   }
 242
 243   mPipe = std::move(*pipe);
 244
 245   mFrameRect = aFrameInfo.mFrameRect;
 246   mPass = 0;
 247
 248   MOZ_LOG(sPNGDecoderAccountingLog, LogLevel::Debug,
 249           ("PNGDecoderAccounting: nsPNGDecoder::CreateFrame -- created "
 250            "image frame with %dx%d pixels for decoder %p",
 251            mFrameRect.Width(), mFrameRect.Height(), this));
 252
 253   return NS_OK;
 254 }
 255
 256 // set timeout and frame disposal method for the current frame
 257 void nsPNGDecoder::EndImageFrame() {
 258   if (mFrameIsHidden) {
 259     return;
 260   }
 261
 262   mNumFrames++;
 263
 264   Opacity opacity = mFormat == SurfaceFormat::OS_RGBX
 265                         ? Opacity::FULLY_OPAQUE
 266                         : Opacity::SOME_TRANSPARENCY;
 267
 268   PostFrameStop(opacity);
 269 }
 270
 271 nsresult nsPNGDecoder::InitInternal() {
 272   mDisablePremultipliedAlpha =
 273       bool(GetSurfaceFlags() & SurfaceFlags::NO_PREMULTIPLY_ALPHA);
 274
 275 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
 276   static png_byte color_chunks[] = {99,  72, 82, 77, '\0',     // cHRM
 277                                     105, 67, 67, 80, '\0'};    // iCCP
 278   static png_byte unused_chunks[] = {98,  75, 71, 68,  '\0',   // bKGD
 279                                      101, 88, 73, 102, '\0',   // eXIf
 280                                      104, 73, 83, 84,  '\0',   // hIST
 281                                      105, 84, 88, 116, '\0',   // iTXt
 282                                      111, 70, 70, 115, '\0',   // oFFs
 283                                      112, 67, 65, 76,  '\0',   // pCAL
 284                                      115, 67, 65, 76,  '\0',   // sCAL
 285                                      112, 72, 89, 115, '\0',   // pHYs
 286                                      115, 66, 73, 84,  '\0',   // sBIT
 287                                      115, 80, 76, 84,  '\0',   // sPLT
 288                                      116, 69, 88, 116, '\0',   // tEXt
 289                                      116, 73, 77, 69,  '\0',   // tIME
 290                                      122, 84, 88, 116, '\0'};  // zTXt
 291 #endif
 292
 293   // Initialize the container's source image header
 294   // Always decode to 24 bit pixdepth
 295
 296   mPNG = png_create_read_struct(PNG_LIBPNG_VER_STRING, nullptr,
 297                                 nsPNGDecoder::error_callback,
 298                                 nsPNGDecoder::warning_callback);
 299   if (!mPNG) {
 300     return NS_ERROR_OUT_OF_MEMORY;
 301   }
 302
 303   mInfo = png_create_info_struct(mPNG);
 304   if (!mInfo) {
 305     png_destroy_read_struct(&mPNG, nullptr, nullptr);
 306     return NS_ERROR_OUT_OF_MEMORY;
 307   }
 308
 309 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
 310   // Ignore unused chunks
 311   if (mCMSMode == eCMSMode_Off || IsMetadataDecode()) {
 312     png_set_keep_unknown_chunks(mPNG, 1, color_chunks, 2);
 313   }
 314
 315   png_set_keep_unknown_chunks(mPNG, 1, unused_chunks,
 316                               (int)sizeof(unused_chunks) / 5);
 317 #endif
 318
 319 #ifdef PNG_SET_USER_LIMITS_SUPPORTED
 320   png_set_user_limits(mPNG, MOZ_PNG_MAX_WIDTH, MOZ_PNG_MAX_HEIGHT);
 321   png_set_chunk_malloc_max(mPNG, kPngMaxChunkSize);
 322 #endif
 323
 324 #ifdef PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED
 325   // Disallow palette-index checking, for speed; we would ignore the warning
 326   // anyhow.  This feature was added at libpng version 1.5.10 and is disabled
 327   // in the embedded libpng but enabled by default in the system libpng.  This
 328   // call also disables it in the system libpng, for decoding speed.
 329   // Bug #745202.
 330   png_set_check_for_invalid_index(mPNG, 0);
 331 #endif
 332
 333 #ifdef PNG_SET_OPTION_SUPPORTED
 334 #  if defined(PNG_sRGB_PROFILE_CHECKS) && PNG_sRGB_PROFILE_CHECKS >= 0
 335   // Skip checking of sRGB ICC profiles
 336   png_set_option(mPNG, PNG_SKIP_sRGB_CHECK_PROFILE, PNG_OPTION_ON);
 337 #  endif
 338
 339 #  ifdef PNG_MAXIMUM_INFLATE_WINDOW
 340   // Force a larger zlib inflate window as some images in the wild have
 341   // incorrectly set metadata (specifically CMF bits) which prevent us from
 342   // decoding them otherwise.
 343   png_set_option(mPNG, PNG_MAXIMUM_INFLATE_WINDOW, PNG_OPTION_ON);
 344 #  endif
 345 #endif
 346
 347   // use this as libpng "progressive pointer" (retrieve in callbacks)
 348   png_set_progressive_read_fn(
 349       mPNG, static_cast<png_voidp>(this), nsPNGDecoder::info_callback,
 350       nsPNGDecoder::row_callback, nsPNGDecoder::end_callback);
 351
 352   return NS_OK;
 353 }
 354
 355 LexerResult nsPNGDecoder::DoDecode(SourceBufferIterator& aIterator,
 356                                    IResumable* aOnResume) {
 357   MOZ_ASSERT(!HasError(), "Shouldn't call DoDecode after error!");
 358
 359   return mLexer.Lex(aIterator, aOnResume,
 360                     [=](State aState, const char* aData, size_t aLength) {
 361                       switch (aState) {
 362                         case State::PNG_DATA:
 363                           return ReadPNGData(aData, aLength);
 364                         case State::FINISHED_PNG_DATA:
 365                           return FinishedPNGData();
 366                       }
 367                       MOZ_CRASH("Unknown State");
 368                     });
 369 }
 370
 371 LexerTransition<nsPNGDecoder::State> nsPNGDecoder::ReadPNGData(
 372     const char* aData, size_t aLength) {
 373   // If we were waiting until after returning from a yield to call
 374   // CreateFrame(), call it now.
 375   if (mNextFrameInfo) {
 376     if (NS_FAILED(CreateFrame(*mNextFrameInfo))) {
 377       return Transition::TerminateFailure();
 378     }
 379
 380     MOZ_ASSERT(mImageData, "Should have a buffer now");
 381     mNextFrameInfo = Nothing();
 382   }
 383
 384   // libpng uses setjmp/longjmp for error handling.
 385   if (setjmp(png_jmpbuf(mPNG))) {
 386     return Transition::TerminateFailure();
 387   }
 388
 389   // Pass the data off to libpng.
 390   mLastChunkLength = aLength;
 391   mNextTransition = Transition::ContinueUnbuffered(State::PNG_DATA);
 392   png_process_data(mPNG, mInfo,
 393                    reinterpret_cast<unsigned char*>(const_cast<char*>((aData))),
 394                    aLength);
 395
 396   // Make sure that we've reached a terminal state if decoding is done.
 397   MOZ_ASSERT_IF(GetDecodeDone(), mNextTransition.NextStateIsTerminal());
 398   MOZ_ASSERT_IF(HasError(), mNextTransition.NextStateIsTerminal());
 399
 400   // Continue with whatever transition the callback code requested. We
 401   // initialized this to Transition::ContinueUnbuffered(State::PNG_DATA) above,
 402   // so by default we just continue the unbuffered read.
 403   return mNextTransition;
 404 }
 405
 406 LexerTransition<nsPNGDecoder::State> nsPNGDecoder::FinishedPNGData() {
 407   // Since we set up an unbuffered read for SIZE_MAX bytes, if we actually read
 408   // all that data something is really wrong.
 409   MOZ_ASSERT_UNREACHABLE("Read the entire address space?");
 410   return Transition::TerminateFailure();
 411 }
 412
 413 // Sets up gamma pre-correction in libpng before our callback gets called.
 414 // We need to do this if we don't end up with a CMS profile.
 415 static void PNGDoGammaCorrection(png_structp png_ptr, png_infop info_ptr) {
 416   double aGamma;
 417
 418   if (png_get_gAMA(png_ptr, info_ptr, &aGamma)) {
 419     if ((aGamma <= 0.0) || (aGamma > 21474.83)) {
 420       aGamma = 0.45455;
 421       png_set_gAMA(png_ptr, info_ptr, aGamma);
 422     }
 423     png_set_gamma(png_ptr, 2.2, aGamma);
 424   } else {
 425     png_set_gamma(png_ptr, 2.2, 0.45455);
 426   }
 427 }
 428
 429 // Adapted from http://www.littlecms.com/pngchrm.c example code
 430 uint32_t nsPNGDecoder::ReadColorProfile(png_structp png_ptr, png_infop info_ptr,
 431                                         int color_type, bool* sRGBTag) {
 432   // First try to see if iCCP chunk is present
 433   if (png_get_valid(png_ptr, info_ptr, PNG_INFO_iCCP)) {
 434     png_uint_32 profileLen;
 435     png_bytep profileData;
 436     png_charp profileName;
 437     int compression;
 438
 439     png_get_iCCP(png_ptr, info_ptr, &profileName, &compression, &profileData,
 440                  &profileLen);
 441
 442     mInProfile = qcms_profile_from_memory((char*)profileData, profileLen);
 443     if (mInProfile) {
 444       uint32_t profileSpace = qcms_profile_get_color_space(mInProfile);
 445
 446       bool mismatch = false;
 447       if (color_type & PNG_COLOR_MASK_COLOR) {
 448         if (profileSpace != icSigRgbData) {
 449           mismatch = true;
 450         }
 451       } else {
 452         if (profileSpace == icSigRgbData) {
 453           png_set_gray_to_rgb(png_ptr);
 454         } else if (profileSpace != icSigGrayData) {
 455           mismatch = true;
 456         }
 457       }
 458
 459       if (mismatch) {
 460         qcms_profile_release(mInProfile);
 461         mInProfile = nullptr;
 462       } else {
 463         return qcms_profile_get_rendering_intent(mInProfile);
 464       }
 465     }
 466   }
 467
 468   // Check sRGB chunk
 469   if (png_get_valid(png_ptr, info_ptr, PNG_INFO_sRGB)) {
 470     *sRGBTag = true;
 471
 472     int fileIntent;
 473     png_set_gray_to_rgb(png_ptr);
 474     png_get_sRGB(png_ptr, info_ptr, &fileIntent);
 475     uint32_t map[] = {QCMS_INTENT_PERCEPTUAL, QCMS_INTENT_RELATIVE_COLORIMETRIC,
 476                       QCMS_INTENT_SATURATION,
 477                       QCMS_INTENT_ABSOLUTE_COLORIMETRIC};
 478     return map[fileIntent];
 479   }
 480
 481   // Check gAMA/cHRM chunks
 482   if (png_get_valid(png_ptr, info_ptr, PNG_INFO_gAMA) &&
 483       png_get_valid(png_ptr, info_ptr, PNG_INFO_cHRM)) {
 484     qcms_CIE_xyYTRIPLE primaries;
 485     qcms_CIE_xyY whitePoint;
 486
 487     png_get_cHRM(png_ptr, info_ptr, &whitePoint.x, &whitePoint.y,
 488                  &primaries.red.x, &primaries.red.y, &primaries.green.x,
 489                  &primaries.green.y, &primaries.blue.x, &primaries.blue.y);
 490     whitePoint.Y = primaries.red.Y = primaries.green.Y = primaries.blue.Y = 1.0;
 491
 492     double gammaOfFile;
 493
 494     png_get_gAMA(png_ptr, info_ptr, &gammaOfFile);
 495
 496     mInProfile = qcms_profile_create_rgb_with_gamma(whitePoint, primaries,
 497                                                     1.0 / gammaOfFile);
 498
 499     if (mInProfile) {
 500       png_set_gray_to_rgb(png_ptr);
 501     }
 502   }
 503
 504   return QCMS_INTENT_PERCEPTUAL;  // Our default
 505 }
 506
 507 void nsPNGDecoder::info_callback(png_structp png_ptr, png_infop info_ptr) {
 508   png_uint_32 width, height;
 509   int bit_depth, color_type, interlace_type, compression_type, filter_type;
 510   unsigned int channels;
 511
 512   png_bytep trans = nullptr;
 513   int num_trans = 0;
 514
 515   nsPNGDecoder* decoder =
 516       static_cast<nsPNGDecoder*>(png_get_progressive_ptr(png_ptr));
 517
 518   if (decoder->mGotInfoCallback) {
 519     MOZ_LOG(sPNGLog, LogLevel::Warning,
 520             ("libpng called info_callback more than once\n"));
 521     return;
 522   }
 523
 524   decoder->mGotInfoCallback = true;
 525
 526   // Always decode to 24-bit RGB or 32-bit RGBA
 527   png_get_IHDR(png_ptr, info_ptr, &width, &height, &bit_depth, &color_type,
 528                &interlace_type, &compression_type, &filter_type);
 529
 530   const IntRect frameRect(0, 0, width, height);
 531
 532   // Post our size to the superclass
 533   decoder->PostSize(frameRect.Width(), frameRect.Height());
 534
 535   if (width > SurfaceCache::MaximumCapacity() / (bit_depth > 8 ? 16 : 8)) {
 536     // libpng needs space to allocate two row buffers
 537     png_error(decoder->mPNG, "Image is too wide");
 538   }
 539
 540   if (decoder->HasError()) {
 541     // Setting the size led to an error.
 542     png_error(decoder->mPNG, "Sizing error");
 543   }
 544
 545   if (color_type == PNG_COLOR_TYPE_PALETTE) {
 546     png_set_expand(png_ptr);
 547   }
 548
 549   if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8) {
 550     png_set_expand(png_ptr);
 551   }
 552
 553   if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)) {
 554     png_color_16p trans_values;
 555     png_get_tRNS(png_ptr, info_ptr, &trans, &num_trans, &trans_values);
 556     // libpng doesn't reject a tRNS chunk with out-of-range samples
 557     // so we check it here to avoid setting up a useless opacity
 558     // channel or producing unexpected transparent pixels (bug #428045)
 559     if (bit_depth < 16) {
 560       png_uint_16 sample_max = (1 << bit_depth) - 1;
 561       if ((color_type == PNG_COLOR_TYPE_GRAY &&
 562            trans_values->gray > sample_max) ||
 563           (color_type == PNG_COLOR_TYPE_RGB &&
 564            (trans_values->red > sample_max ||
 565             trans_values->green > sample_max ||
 566             trans_values->blue > sample_max))) {
 567         // clear the tRNS valid flag and release tRNS memory
 568         png_free_data(png_ptr, info_ptr, PNG_FREE_TRNS, 0);
 569         num_trans = 0;
 570       }
 571     }
 572     if (num_trans != 0) {
 573       png_set_expand(png_ptr);
 574     }
 575   }
 576
 577   if (bit_depth == 16) {
 578     png_set_scale_16(png_ptr);
 579   }
 580
 581   // We only need to extract the color profile for non-metadata decodes. It is
 582   // fairly expensive to read the profile and create the transform so we should
 583   // avoid it if not necessary.
 584   uint32_t intent = -1;
 585   bool sRGBTag = false;
 586   if (!decoder->IsMetadataDecode()) {
 587     if (decoder->mCMSMode != eCMSMode_Off) {
 588       intent = gfxPlatform::GetRenderingIntent();
 589       uint32_t pIntent =
 590           decoder->ReadColorProfile(png_ptr, info_ptr, color_type, &sRGBTag);
 591       // If we're not mandating an intent, use the one from the image.
 592       if (intent == uint32_t(-1)) {
 593         intent = pIntent;
 594       }
 595     }
 596     if (!decoder->mInProfile || !decoder->GetCMSOutputProfile()) {
 597       png_set_gray_to_rgb(png_ptr);
 598
 599       // only do gamma correction if CMS isn't entirely disabled
 600       if (decoder->mCMSMode != eCMSMode_Off) {
 601         PNGDoGammaCorrection(png_ptr, info_ptr);
 602       }
 603     }
 604   }
 605
 606   // Let libpng expand interlaced images.
 607   const bool isInterlaced = interlace_type == PNG_INTERLACE_ADAM7;
 608   if (isInterlaced) {
 609     png_set_interlace_handling(png_ptr);
 610   }
 611
 612   // now all of those things we set above are used to update various struct
 613   // members and whatnot, after which we can get channels, rowbytes, etc.
 614   png_read_update_info(png_ptr, info_ptr);
 615   decoder->mChannels = channels = png_get_channels(png_ptr, info_ptr);
 616
 617   //---------------------------------------------------------------//
 618   // copy PNG info into imagelib structs (formerly png_set_dims()) //
 619   //---------------------------------------------------------------//
 620
 621   if (channels < 1 || channels > 4) {
 622     png_error(decoder->mPNG, "Invalid number of channels");
 623   }
 624
 625 #ifdef PNG_APNG_SUPPORTED
 626   bool isAnimated = png_get_valid(png_ptr, info_ptr, PNG_INFO_acTL);
 627   if (isAnimated) {
 628     int32_t rawTimeout = GetNextFrameDelay(png_ptr, info_ptr);
 629     decoder->PostIsAnimated(FrameTimeout::FromRawMilliseconds(rawTimeout));
 630
 631     if (decoder->Size() != decoder->OutputSize() &&
 632         !decoder->IsFirstFrameDecode()) {
 633       MOZ_ASSERT_UNREACHABLE(
 634           "Doing downscale-during-decode "
 635           "for an animated image?");
 636       png_error(decoder->mPNG, "Invalid downscale attempt");  // Abort decode.
 637     }
 638   }
 639 #endif
 640
 641   auto transparency = decoder->GetTransparencyType(frameRect);
 642   if (decoder->IsMetadataDecode()) {
 643     // If we are animated then the first frame rect is either:
 644     // 1) the whole image if the IDAT chunk is part of the animation
 645     // 2) the frame rect of the first fDAT chunk otherwise.
 646     // If we are not animated then we want to make sure to call
 647     // PostHasTransparency in the metadata decode if we need to. So it's
 648     // okay to pass IntRect(0, 0, width, height) here for animated images;
 649     // they will call with the proper first frame rect in the full decode.
 650     decoder->PostHasTransparencyIfNeeded(transparency);
 651
 652     // We have the metadata we're looking for, so stop here, before we allocate
 653     // buffers below.
 654     return decoder->DoTerminate(png_ptr, TerminalState::SUCCESS);
 655   }
 656
 657   if (decoder->mInProfile && decoder->GetCMSOutputProfile()) {
 658     qcms_data_type inType;
 659     qcms_data_type outType;
 660
 661     uint32_t profileSpace = qcms_profile_get_color_space(decoder->mInProfile);
 662     decoder->mUsePipeTransform = profileSpace != icSigGrayData;
 663     if (decoder->mUsePipeTransform) {
 664       // If the transform happens with SurfacePipe, it will be in RGBA if we
 665       // have an alpha channel, because the swizzle and premultiplication
 666       // happens after color management. Otherwise it will be in BGRA because
 667       // the swizzle happens at the start.
 668       if (transparency == TransparencyType::eAlpha) {
 669         inType = QCMS_DATA_RGBA_8;
 670         outType = QCMS_DATA_RGBA_8;
 671       } else {
 672         inType = gfxPlatform::GetCMSOSRGBAType();
 673         outType = inType;
 674       }
 675     } else {
 676       if (color_type & PNG_COLOR_MASK_ALPHA) {
 677         inType = QCMS_DATA_GRAYA_8;
 678         outType = gfxPlatform::GetCMSOSRGBAType();
 679       } else {
 680         inType = QCMS_DATA_GRAY_8;
 681         outType = gfxPlatform::GetCMSOSRGBAType();
 682       }
 683     }
 684
 685     decoder->mTransform = qcms_transform_create(decoder->mInProfile, inType,
 686                                                 decoder->GetCMSOutputProfile(),
 687                                                 outType, (qcms_intent)intent);
 688   } else if ((sRGBTag && decoder->mCMSMode == eCMSMode_TaggedOnly) ||
 689              decoder->mCMSMode == eCMSMode_All) {
 690     // If the transform happens with SurfacePipe, it will be in RGBA if we
 691     // have an alpha channel, because the swizzle and premultiplication
 692     // happens after color management. Otherwise it will be in OS_RGBA because
 693     // the swizzle happens at the start.
 694     if (transparency == TransparencyType::eAlpha) {
 695       decoder->mTransform =
 696           decoder->GetCMSsRGBTransform(SurfaceFormat::R8G8B8A8);
 697     } else {
 698       decoder->mTransform =
 699           decoder->GetCMSsRGBTransform(SurfaceFormat::OS_RGBA);
 700     }
 701     decoder->mUsePipeTransform = true;
 702   }
 703
 704 #ifdef PNG_APNG_SUPPORTED
 705   if (isAnimated) {
 706     png_set_progressive_frame_fn(png_ptr, nsPNGDecoder::frame_info_callback,
 707                                  nullptr);
 708   }
 709
 710   if (png_get_first_frame_is_hidden(png_ptr, info_ptr)) {
 711     decoder->mFrameIsHidden = true;
 712   } else {
 713 #endif
 714     nsresult rv = decoder->CreateFrame(FrameInfo{frameRect, isInterlaced});
 715     if (NS_FAILED(rv)) {
 716       png_error(decoder->mPNG, "CreateFrame failed");
 717     }
 718     MOZ_ASSERT(decoder->mImageData, "Should have a buffer now");
 719 #ifdef PNG_APNG_SUPPORTED
 720   }
 721 #endif
 722
 723   if (decoder->mTransform && !decoder->mUsePipeTransform) {
 724     decoder->mCMSLine =
 725         static_cast<uint8_t*>(malloc(sizeof(uint32_t) * frameRect.Width()));
 726     if (!decoder->mCMSLine) {
 727       png_error(decoder->mPNG, "malloc of mCMSLine failed");
 728     }
 729   }
 730
 731   if (interlace_type == PNG_INTERLACE_ADAM7) {
 732     if (frameRect.Height() <
 733         INT32_MAX / (frameRect.Width() * int32_t(channels))) {
 734       const size_t bufferSize =
 735           channels * frameRect.Width() * frameRect.Height();
 736
 737       if (bufferSize > SurfaceCache::MaximumCapacity()) {
 738         png_error(decoder->mPNG, "Insufficient memory to deinterlace image");
 739       }
 740
 741       decoder->interlacebuf = static_cast<uint8_t*>(malloc(bufferSize));
 742     }
 743     if (!decoder->interlacebuf) {
 744       png_error(decoder->mPNG, "malloc of interlacebuf failed");
 745     }
 746   }
 747 }
 748
 749 void nsPNGDecoder::PostInvalidationIfNeeded() {
 750   Maybe<SurfaceInvalidRect> invalidRect = mPipe.TakeInvalidRect();
 751   if (!invalidRect) {
 752     return;
 753   }
 754
 755   PostInvalidation(invalidRect->mInputSpaceRect,
 756                    Some(invalidRect->mOutputSpaceRect));
 757 }
 758
 759 void nsPNGDecoder::row_callback(png_structp png_ptr, png_bytep new_row,
 760                                 png_uint_32 row_num, int pass) {
 761   /* libpng comments:
 762    *
 763    * This function is called for every row in the image.  If the
 764    * image is interlacing, and you turned on the interlace handler,
 765    * this function will be called for every row in every pass.
 766    * Some of these rows will not be changed from the previous pass.
 767    * When the row is not changed, the new_row variable will be
 768    * nullptr. The rows and passes are called in order, so you don't
 769    * really need the row_num and pass, but I'm supplying them
 770    * because it may make your life easier.
 771    *
 772    * For the non-nullptr rows of interlaced images, you must call
 773    * png_progressive_combine_row() passing in the row and the
 774    * old row.  You can call this function for nullptr rows (it will
 775    * just return) and for non-interlaced images (it just does the
 776    * memcpy for you) if it will make the code easier.  Thus, you
 777    * can just do this for all cases:
 778    *
 779    *    png_progressive_combine_row(png_ptr, old_row, new_row);
 780    *
 781    * where old_row is what was displayed for previous rows.  Note
 782    * that the first pass (pass == 0 really) will completely cover
 783    * the old row, so the rows do not have to be initialized.  After
 784    * the first pass (and only for interlaced images), you will have
 785    * to pass the current row, and the function will combine the
 786    * old row and the new row.
 787    */
 788   nsPNGDecoder* decoder =
 789       static_cast<nsPNGDecoder*>(png_get_progressive_ptr(png_ptr));
 790
 791   if (decoder->mFrameIsHidden) {
 792     return;  // Skip this frame.
 793   }
 794
 795   MOZ_ASSERT_IF(decoder->IsFirstFrameDecode(), decoder->mNumFrames == 0);
 796
 797   while (pass > decoder->mPass) {
 798     // Advance to the next pass. We may have to do this multiple times because
 799     // libpng will skip passes if the image is so small that no pixels have
 800     // changed on a given pass, but ADAM7InterpolatingFilter needs to be reset
 801     // once for every pass to perform interpolation properly.
 802     decoder->mPipe.ResetToFirstRow();
 803     decoder->mPass++;
 804   }
 805
 806   const png_uint_32 height =
 807       static_cast<png_uint_32>(decoder->mFrameRect.Height());
 808
 809   if (row_num >= height) {
 810     // Bail if we receive extra rows. This is especially important because if we
 811     // didn't, we might overflow the deinterlacing buffer.
 812     MOZ_ASSERT_UNREACHABLE("libpng producing extra rows?");
 813     return;
 814   }
 815
 816   // Note that |new_row| may be null here, indicating that this is an interlaced
 817   // image and |row_callback| is being called for a row that hasn't changed.
 818   MOZ_ASSERT_IF(!new_row, decoder->interlacebuf);
 819
 820   if (decoder->interlacebuf) {
 821     uint32_t width = uint32_t(decoder->mFrameRect.Width());
 822
 823     // We'll output the deinterlaced version of the row.
 824     uint8_t* rowToWrite =
 825         decoder->interlacebuf + (row_num * decoder->mChannels * width);
 826
 827     // Update the deinterlaced version of this row with the new data.
 828     png_progressive_combine_row(png_ptr, rowToWrite, new_row);
 829
 830     decoder->WriteRow(rowToWrite);
 831   } else {
 832     decoder->WriteRow(new_row);
 833   }
 834 }
 835
 836 void nsPNGDecoder::WriteRow(uint8_t* aRow) {
 837   MOZ_ASSERT(aRow);
 838
 839   uint8_t* rowToWrite = aRow;
 840   uint32_t width = uint32_t(mFrameRect.Width());
 841
 842   // Apply color management to the row, if necessary, before writing it out.
 843   // This is only needed for grayscale images.
 844   if (mTransform && !mUsePipeTransform) {
 845     MOZ_ASSERT(mCMSLine);
 846     qcms_transform_data(mTransform, rowToWrite, mCMSLine, width);
 847     rowToWrite = mCMSLine;
 848   }
 849
 850   // Write this row to the SurfacePipe.
 851   DebugOnly<WriteState> result =
 852       mPipe.WriteBuffer(reinterpret_cast<uint32_t*>(rowToWrite));
 853   MOZ_ASSERT(WriteState(result) != WriteState::FAILURE);
 854
 855   PostInvalidationIfNeeded();
 856 }
 857
 858 void nsPNGDecoder::DoTerminate(png_structp aPNGStruct, TerminalState aState) {
 859   // Stop processing data. Note that we intentionally ignore the return value of
 860   // png_process_data_pause(), which tells us how many bytes of the data that
 861   // was passed to png_process_data() have not been consumed yet, because now
 862   // that we've reached a terminal state, we won't do any more decoding or call
 863   // back into libpng anymore.
 864   png_process_data_pause(aPNGStruct, /* save = */ false);
 865
 866   mNextTransition = aState == TerminalState::SUCCESS
 867                         ? Transition::TerminateSuccess()
 868                         : Transition::TerminateFailure();
 869 }
 870
 871 void nsPNGDecoder::DoYield(png_structp aPNGStruct) {
 872   // Pause data processing. png_process_data_pause() returns how many bytes of
 873   // the data that was passed to png_process_data() have not been consumed yet.
 874   // We use this information to tell StreamingLexer where to place us in the
 875   // input stream when we come back from the yield.
 876   png_size_t pendingBytes = png_process_data_pause(aPNGStruct,
 877                                                    /* save = */ false);
 878
 879   MOZ_ASSERT(pendingBytes < mLastChunkLength);
 880   size_t consumedBytes = mLastChunkLength - min(pendingBytes, mLastChunkLength);
 881
 882   mNextTransition =
 883       Transition::ContinueUnbufferedAfterYield(State::PNG_DATA, consumedBytes);
 884 }
 885
 886 nsresult nsPNGDecoder::FinishInternal() {
 887   // We shouldn't be called in error cases.
 888   MOZ_ASSERT(!HasError(), "Can't call FinishInternal on error!");
 889
 890   if (IsMetadataDecode()) {
 891     return NS_OK;
 892   }
 893
 894   int32_t loop_count = 0;
 895 #ifdef PNG_APNG_SUPPORTED
 896   if (png_get_valid(mPNG, mInfo, PNG_INFO_acTL)) {
 897     int32_t num_plays = png_get_num_plays(mPNG, mInfo);
 898     loop_count = num_plays - 1;
 899   }
 900 #endif
 901
 902   if (InFrame()) {
 903     EndImageFrame();
 904   }
 905   PostDecodeDone(loop_count);
 906
 907   return NS_OK;
 908 }
 909
 910 #ifdef PNG_APNG_SUPPORTED
 911 // got the header of a new frame that's coming
 912 void nsPNGDecoder::frame_info_callback(png_structp png_ptr,
 913                                        png_uint_32 frame_num) {
 914   nsPNGDecoder* decoder =
 915       static_cast<nsPNGDecoder*>(png_get_progressive_ptr(png_ptr));
 916
 917   // old frame is done
 918   decoder->EndImageFrame();
 919
 920   const bool previousFrameWasHidden = decoder->mFrameIsHidden;
 921
 922   if (!previousFrameWasHidden && decoder->IsFirstFrameDecode()) {
 923     // We're about to get a second non-hidden frame, but we only want the first.
 924     // Stop decoding now. (And avoid allocating the unnecessary buffers below.)
 925     return decoder->DoTerminate(png_ptr, TerminalState::SUCCESS);
 926   }
 927
 928   // Only the first frame can be hidden, so unhide unconditionally here.
 929   decoder->mFrameIsHidden = false;
 930
 931   // Save the information necessary to create the frame; we'll actually create
 932   // it when we return from the yield.
 933   const IntRect frameRect(png_get_next_frame_x_offset(png_ptr, decoder->mInfo),
 934                           png_get_next_frame_y_offset(png_ptr, decoder->mInfo),
 935                           png_get_next_frame_width(png_ptr, decoder->mInfo),
 936                           png_get_next_frame_height(png_ptr, decoder->mInfo));
 937   const bool isInterlaced = bool(decoder->interlacebuf);
 938
 939 #  ifndef MOZ_EMBEDDED_LIBPNG
 940   // if using system library, check frame_width and height against 0
 941   if (frameRect.width == 0) {
 942     png_error(png_ptr, "Frame width must not be 0");
 943   }
 944   if (frameRect.height == 0) {
 945     png_error(png_ptr, "Frame height must not be 0");
 946   }
 947 #  endif
 948
 949   const FrameInfo info{frameRect, isInterlaced};
 950
 951   // If the previous frame was hidden, skip the yield (which will mislead the
 952   // caller, who will think the previous frame was real) and just allocate the
 953   // new frame here.
 954   if (previousFrameWasHidden) {
 955     if (NS_FAILED(decoder->CreateFrame(info))) {
 956       return decoder->DoTerminate(png_ptr, TerminalState::FAILURE);
 957     }
 958
 959     MOZ_ASSERT(decoder->mImageData, "Should have a buffer now");
 960     return;  // No yield, so we'll just keep decoding.
 961   }
 962
 963   // Yield to the caller to notify them that the previous frame is now complete.
 964   decoder->mNextFrameInfo = Some(info);
 965   return decoder->DoYield(png_ptr);
 966 }
 967 #endif
 968
 969 void nsPNGDecoder::end_callback(png_structp png_ptr, png_infop info_ptr) {
 970   /* libpng comments:
 971    *
 972    * this function is called when the whole image has been read,
 973    * including any chunks after the image (up to and including
 974    * the IEND).  You will usually have the same info chunk as you
 975    * had in the header, although some data may have been added
 976    * to the comments and time fields.
 977    *
 978    * Most people won't do much here, perhaps setting a flag that
 979    * marks the image as finished.
 980    */
 981
 982   nsPNGDecoder* decoder =
 983       static_cast<nsPNGDecoder*>(png_get_progressive_ptr(png_ptr));
 984
 985   // We shouldn't get here if we've hit an error
 986   MOZ_ASSERT(!decoder->HasError(), "Finishing up PNG but hit error!");
 987
 988   return decoder->DoTerminate(png_ptr, TerminalState::SUCCESS);
 989 }
 990
 991 void nsPNGDecoder::error_callback(png_structp png_ptr,
 992                                   png_const_charp error_msg) {
 993   MOZ_LOG(sPNGLog, LogLevel::Error, ("libpng error: %s\n", error_msg));
 994   png_longjmp(png_ptr, 1);
 995 }
 996
 997 void nsPNGDecoder::warning_callback(png_structp png_ptr,
 998                                     png_const_charp warning_msg) {
 999   MOZ_LOG(sPNGLog, LogLevel::Warning, ("libpng warning: %s\n", warning_msg));
1000 }
1001
1002 Maybe<Telemetry::HistogramID> nsPNGDecoder::SpeedHistogram() const {
1003   return Some(Telemetry::IMAGE_DECODE_SPEED_PNG);
1004 }
1005
1006 bool nsPNGDecoder::IsValidICOResource() const {
1007   // Only 32-bit RGBA PNGs are valid ICO resources; see here:
1008   //   http://blogs.msdn.com/b/oldnewthing/archive/2010/10/22/10079192.aspx
1009
1010   // If there are errors in the call to png_get_IHDR, the error_callback in
1011   // nsPNGDecoder.cpp is called.  In this error callback we do a longjmp, so
1012   // we need to save the jump buffer here. Otherwise we'll end up without a
1013   // proper callstack.
1014   if (setjmp(png_jmpbuf(mPNG))) {
1015     // We got here from a longjmp call indirectly from png_get_IHDR
1016     return false;
1017   }
1018
1019   png_uint_32 png_width,  // Unused
1020       png_height;         // Unused
1021
1022   int png_bit_depth, png_color_type;
1023
1024   if (png_get_IHDR(mPNG, mInfo, &png_width, &png_height, &png_bit_depth,
1025                    &png_color_type, nullptr, nullptr, nullptr)) {
1026     return ((png_color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
1027              png_color_type == PNG_COLOR_TYPE_RGB) &&
1028             png_bit_depth == 8);
1029   } else {
1030     return false;
1031   }
1032 }
1033
1034 }  // namespace image
1035 }  // namespace mozilla