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 "nsRect.h"
  18 #include "nspr.h"
  19 #include "png.h"
  20
  21 #include "RasterImage.h"
  22 #include "SurfaceCache.h"
  23 #include "SurfacePipeFactory.h"
  24 #include "mozilla/DebugOnly.h"
  25 #include "mozilla/Telemetry.h"
  26
  27 using namespace mozilla::gfx;
  28
  29 using std::min;
  30
  31 namespace mozilla {
  32 namespace image {
  33
  34 static LazyLogModule sPNGLog("PNGDecoder");
  35 static LazyLogModule sPNGDecoderAccountingLog("PNGDecoderAccounting");
  36
  37 // limit image dimensions (bug #251381, #591822, #967656, and #1283961)
  38 #ifndef MOZ_PNG_MAX_WIDTH
  39 #  define MOZ_PNG_MAX_WIDTH 0x7fffffff  // Unlimited
  40 #endif
  41 #ifndef MOZ_PNG_MAX_HEIGHT
  42 #  define MOZ_PNG_MAX_HEIGHT 0x7fffffff  // Unlimited
  43 #endif
  44
  45 /* Controls the maximum chunk size configuration for libpng. We set this to a
  46  * very large number, 256MB specifically. */
  47 static constexpr png_alloc_size_t kPngMaxChunkSize = 0x10000000;
  48
  49 nsPNGDecoder::AnimFrameInfo::AnimFrameInfo()
  50     : mDispose(DisposalMethod::KEEP), mBlend(BlendMethod::OVER), mTimeout(0) {}
  51
  52 #ifdef PNG_APNG_SUPPORTED
  53
  54 int32_t GetNextFrameDelay(png_structp aPNG, png_infop aInfo) {
  55   // Delay, in seconds, is delayNum / delayDen.
  56   png_uint_16 delayNum = png_get_next_frame_delay_num(aPNG, aInfo);
  57   png_uint_16 delayDen = png_get_next_frame_delay_den(aPNG, aInfo);
  58
  59   if (delayNum == 0) {
  60     return 0;  // SetFrameTimeout() will set to a minimum.
  61   }
  62
  63   if (delayDen == 0) {
  64     delayDen = 100;  // So says the APNG spec.
  65   }
  66
  67   // Need to cast delay_num to float to have a proper division and
  68   // the result to int to avoid a compiler warning.
  69   return static_cast<int32_t>(static_cast<double>(delayNum) * 1000 / delayDen);
  70 }
  71
  72 nsPNGDecoder::AnimFrameInfo::AnimFrameInfo(png_structp aPNG, png_infop aInfo)
  73     : mDispose(DisposalMethod::KEEP), mBlend(BlendMethod::OVER), mTimeout(0) {
  74   png_byte dispose_op = png_get_next_frame_dispose_op(aPNG, aInfo);
  75   png_byte blend_op = png_get_next_frame_blend_op(aPNG, aInfo);
  76
  77   if (dispose_op == PNG_DISPOSE_OP_PREVIOUS) {
  78     mDispose = DisposalMethod::RESTORE_PREVIOUS;
  79   } else if (dispose_op == PNG_DISPOSE_OP_BACKGROUND) {
  80     mDispose = DisposalMethod::CLEAR;
  81   } else {
  82     mDispose = DisposalMethod::KEEP;
  83   }
  84
  85   if (blend_op == PNG_BLEND_OP_SOURCE) {
  86     mBlend = BlendMethod::SOURCE;
  87   } else {
  88     mBlend = BlendMethod::OVER;
  89   }
  90
  91   mTimeout = GetNextFrameDelay(aPNG, aInfo);
  92 }
  93 #endif
  94
  95 // First 8 bytes of a PNG file
  96 const uint8_t nsPNGDecoder::pngSignatureBytes[] = {137, 80, 78, 71,
  97                                                    13,  10, 26, 10};
  98
  99 nsPNGDecoder::nsPNGDecoder(RasterImage* aImage)
 100     : Decoder(aImage),
 101       mLexer(Transition::ToUnbuffered(State::FINISHED_PNG_DATA, State::PNG_DATA,
 102                                       SIZE_MAX),
 103              Transition::TerminateSuccess()),
 104       mNextTransition(Transition::ContinueUnbuffered(State::PNG_DATA)),
 105       mLastChunkLength(0),
 106       mPNG(nullptr),
 107       mInfo(nullptr),
 108       mCMSLine(nullptr),
 109       interlacebuf(nullptr),
 110       mFormat(SurfaceFormat::UNKNOWN),
 111       mChannels(0),
 112       mPass(0),
 113       mFrameIsHidden(false),
 114       mDisablePremultipliedAlpha(false),
 115       mGotInfoCallback(false),
 116       mUsePipeTransform(false),
 117       mErrorIsRecoverable(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 OrientedIntRect& 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.ToUnknownRect(),
 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 == CMSMode::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 (GetFrameCount() > 0 && mErrorIsRecoverable)
 387                ? Transition::TerminateSuccess()
 388                : Transition::TerminateFailure();
 389   }
 390
 391   // Pass the data off to libpng.
 392   mLastChunkLength = aLength;
 393   mNextTransition = Transition::ContinueUnbuffered(State::PNG_DATA);
 394   png_process_data(mPNG, mInfo,
 395                    reinterpret_cast<unsigned char*>(const_cast<char*>((aData))),
 396                    aLength);
 397
 398   // Make sure that we've reached a terminal state if decoding is done.
 399   MOZ_ASSERT_IF(GetDecodeDone(), mNextTransition.NextStateIsTerminal());
 400   MOZ_ASSERT_IF(HasError(), mNextTransition.NextStateIsTerminal());
 401
 402   // Continue with whatever transition the callback code requested. We
 403   // initialized this to Transition::ContinueUnbuffered(State::PNG_DATA) above,
 404   // so by default we just continue the unbuffered read.
 405   return mNextTransition;
 406 }
 407
 408 LexerTransition<nsPNGDecoder::State> nsPNGDecoder::FinishedPNGData() {
 409   // Since we set up an unbuffered read for SIZE_MAX bytes, if we actually read
 410   // all that data something is really wrong.
 411   MOZ_ASSERT_UNREACHABLE("Read the entire address space?");
 412   return Transition::TerminateFailure();
 413 }
 414
 415 // Sets up gamma pre-correction in libpng before our callback gets called.
 416 // We need to do this if we don't end up with a CMS profile.
 417 static void PNGDoGammaCorrection(png_structp png_ptr, png_infop info_ptr) {
 418   double aGamma;
 419
 420   if (png_get_gAMA(png_ptr, info_ptr, &aGamma)) {
 421     if ((aGamma <= 0.0) || (aGamma > 21474.83)) {
 422       aGamma = 0.45455;
 423       png_set_gAMA(png_ptr, info_ptr, aGamma);
 424     }
 425     png_set_gamma(png_ptr, 2.2, aGamma);
 426   } else {
 427     png_set_gamma(png_ptr, 2.2, 0.45455);
 428   }
 429 }
 430
 431 // Adapted from http://www.littlecms.com/pngchrm.c example code
 432 uint32_t nsPNGDecoder::ReadColorProfile(png_structp png_ptr, png_infop info_ptr,
 433                                         int color_type, bool* sRGBTag) {
 434   // First try to see if iCCP chunk is present
 435   if (png_get_valid(png_ptr, info_ptr, PNG_INFO_iCCP)) {
 436     png_uint_32 profileLen;
 437     png_bytep profileData;
 438     png_charp profileName;
 439     int compression;
 440
 441     png_get_iCCP(png_ptr, info_ptr, &profileName, &compression, &profileData,
 442                  &profileLen);
 443
 444     mInProfile = qcms_profile_from_memory((char*)profileData, profileLen);
 445     if (mInProfile) {
 446       uint32_t profileSpace = qcms_profile_get_color_space(mInProfile);
 447
 448       bool mismatch = false;
 449       if (color_type & PNG_COLOR_MASK_COLOR) {
 450         if (profileSpace != icSigRgbData) {
 451           mismatch = true;
 452         }
 453       } else {
 454         if (profileSpace == icSigRgbData) {
 455           png_set_gray_to_rgb(png_ptr);
 456         } else if (profileSpace != icSigGrayData) {
 457           mismatch = true;
 458         }
 459       }
 460
 461       if (mismatch) {
 462         qcms_profile_release(mInProfile);
 463         mInProfile = nullptr;
 464       } else {
 465         return qcms_profile_get_rendering_intent(mInProfile);
 466       }
 467     }
 468   }
 469
 470   // Check sRGB chunk
 471   if (png_get_valid(png_ptr, info_ptr, PNG_INFO_sRGB)) {
 472     *sRGBTag = true;
 473
 474     int fileIntent;
 475     png_set_gray_to_rgb(png_ptr);
 476     png_get_sRGB(png_ptr, info_ptr, &fileIntent);
 477     uint32_t map[] = {QCMS_INTENT_PERCEPTUAL, QCMS_INTENT_RELATIVE_COLORIMETRIC,
 478                       QCMS_INTENT_SATURATION,
 479                       QCMS_INTENT_ABSOLUTE_COLORIMETRIC};
 480     return map[fileIntent];
 481   }
 482
 483   // Check gAMA/cHRM chunks
 484   if (png_get_valid(png_ptr, info_ptr, PNG_INFO_gAMA) &&
 485       png_get_valid(png_ptr, info_ptr, PNG_INFO_cHRM)) {
 486     qcms_CIE_xyYTRIPLE primaries;
 487     qcms_CIE_xyY whitePoint;
 488
 489     png_get_cHRM(png_ptr, info_ptr, &whitePoint.x, &whitePoint.y,
 490                  &primaries.red.x, &primaries.red.y, &primaries.green.x,
 491                  &primaries.green.y, &primaries.blue.x, &primaries.blue.y);
 492     whitePoint.Y = primaries.red.Y = primaries.green.Y = primaries.blue.Y = 1.0;
 493
 494     double gammaOfFile;
 495
 496     png_get_gAMA(png_ptr, info_ptr, &gammaOfFile);
 497
 498     mInProfile = qcms_profile_create_rgb_with_gamma(whitePoint, primaries,
 499                                                     1.0 / gammaOfFile);
 500
 501     if (mInProfile) {
 502       png_set_gray_to_rgb(png_ptr);
 503     }
 504   }
 505
 506   return QCMS_INTENT_PERCEPTUAL;  // Our default
 507 }
 508
 509 void nsPNGDecoder::info_callback(png_structp png_ptr, png_infop info_ptr) {
 510   png_uint_32 width, height;
 511   int bit_depth, color_type, interlace_type, compression_type, filter_type;
 512   unsigned int channels;
 513
 514   png_bytep trans = nullptr;
 515   int num_trans = 0;
 516
 517   nsPNGDecoder* decoder =
 518       static_cast<nsPNGDecoder*>(png_get_progressive_ptr(png_ptr));
 519
 520   if (decoder->mGotInfoCallback) {
 521     MOZ_LOG(sPNGLog, LogLevel::Warning,
 522             ("libpng called info_callback more than once\n"));
 523     return;
 524   }
 525
 526   decoder->mGotInfoCallback = true;
 527
 528   // Always decode to 24-bit RGB or 32-bit RGBA
 529   png_get_IHDR(png_ptr, info_ptr, &width, &height, &bit_depth, &color_type,
 530                &interlace_type, &compression_type, &filter_type);
 531
 532   const OrientedIntRect frameRect(0, 0, width, height);
 533
 534   // Post our size to the superclass
 535   decoder->PostSize(frameRect.Width(), frameRect.Height());
 536
 537   if (width > SurfaceCache::MaximumCapacity() / (bit_depth > 8 ? 16 : 8)) {
 538     // libpng needs space to allocate two row buffers
 539     png_error(decoder->mPNG, "Image is too wide");
 540   }
 541
 542   if (decoder->HasError()) {
 543     // Setting the size led to an error.
 544     png_error(decoder->mPNG, "Sizing error");
 545   }
 546
 547   if (color_type == PNG_COLOR_TYPE_PALETTE) {
 548     png_set_expand(png_ptr);
 549   }
 550
 551   if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8) {
 552     png_set_expand(png_ptr);
 553   }
 554
 555   if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)) {
 556     png_color_16p trans_values;
 557     png_get_tRNS(png_ptr, info_ptr, &trans, &num_trans, &trans_values);
 558     // libpng doesn't reject a tRNS chunk with out-of-range samples
 559     // so we check it here to avoid setting up a useless opacity
 560     // channel or producing unexpected transparent pixels (bug #428045)
 561     if (bit_depth < 16) {
 562       png_uint_16 sample_max = (1 << bit_depth) - 1;
 563       if ((color_type == PNG_COLOR_TYPE_GRAY &&
 564            trans_values->gray > sample_max) ||
 565           (color_type == PNG_COLOR_TYPE_RGB &&
 566            (trans_values->red > sample_max ||
 567             trans_values->green > sample_max ||
 568             trans_values->blue > sample_max))) {
 569         // clear the tRNS valid flag and release tRNS memory
 570         png_free_data(png_ptr, info_ptr, PNG_FREE_TRNS, 0);
 571         num_trans = 0;
 572       }
 573     }
 574     if (num_trans != 0) {
 575       png_set_expand(png_ptr);
 576     }
 577   }
 578
 579   if (bit_depth == 16) {
 580     png_set_scale_16(png_ptr);
 581   }
 582
 583   // We only need to extract the color profile for non-metadata decodes. It is
 584   // fairly expensive to read the profile and create the transform so we should
 585   // avoid it if not necessary.
 586   uint32_t intent = -1;
 587   bool sRGBTag = false;
 588   if (!decoder->IsMetadataDecode()) {
 589     if (decoder->mCMSMode != CMSMode::Off) {
 590       intent = gfxPlatform::GetRenderingIntent();
 591       uint32_t pIntent =
 592           decoder->ReadColorProfile(png_ptr, info_ptr, color_type, &sRGBTag);
 593       // If we're not mandating an intent, use the one from the image.
 594       if (intent == uint32_t(-1)) {
 595         intent = pIntent;
 596       }
 597     }
 598     if (!decoder->mInProfile || !decoder->GetCMSOutputProfile()) {
 599       png_set_gray_to_rgb(png_ptr);
 600
 601       // only do gamma correction if CMS isn't entirely disabled
 602       if (decoder->mCMSMode != CMSMode::Off) {
 603         PNGDoGammaCorrection(png_ptr, info_ptr);
 604       }
 605     }
 606   }
 607
 608   // Let libpng expand interlaced images.
 609   const bool isInterlaced = interlace_type == PNG_INTERLACE_ADAM7;
 610   if (isInterlaced) {
 611     png_set_interlace_handling(png_ptr);
 612   }
 613
 614   // now all of those things we set above are used to update various struct
 615   // members and whatnot, after which we can get channels, rowbytes, etc.
 616   png_read_update_info(png_ptr, info_ptr);
 617   decoder->mChannels = channels = png_get_channels(png_ptr, info_ptr);
 618
 619   //---------------------------------------------------------------//
 620   // copy PNG info into imagelib structs (formerly png_set_dims()) //
 621   //---------------------------------------------------------------//
 622
 623   if (channels < 1 || channels > 4) {
 624     png_error(decoder->mPNG, "Invalid number of channels");
 625   }
 626
 627 #ifdef PNG_APNG_SUPPORTED
 628   bool isAnimated = png_get_valid(png_ptr, info_ptr, PNG_INFO_acTL);
 629   if (isAnimated) {
 630     int32_t rawTimeout = GetNextFrameDelay(png_ptr, info_ptr);
 631     decoder->PostIsAnimated(FrameTimeout::FromRawMilliseconds(rawTimeout));
 632
 633     if (decoder->Size() != decoder->OutputSize() &&
 634         !decoder->IsFirstFrameDecode()) {
 635       MOZ_ASSERT_UNREACHABLE(
 636           "Doing downscale-during-decode "
 637           "for an animated image?");
 638       png_error(decoder->mPNG, "Invalid downscale attempt");  // Abort decode.
 639     }
 640   }
 641 #endif
 642
 643   auto transparency = decoder->GetTransparencyType(frameRect);
 644   if (decoder->IsMetadataDecode()) {
 645     // If we are animated then the first frame rect is either:
 646     // 1) the whole image if the IDAT chunk is part of the animation
 647     // 2) the frame rect of the first fDAT chunk otherwise.
 648     // If we are not animated then we want to make sure to call
 649     // PostHasTransparency in the metadata decode if we need to. So it's
 650     // okay to pass IntRect(0, 0, width, height) here for animated images;
 651     // they will call with the proper first frame rect in the full decode.
 652     decoder->PostHasTransparencyIfNeeded(transparency);
 653
 654     // We have the metadata we're looking for, so stop here, before we allocate
 655     // buffers below.
 656     return decoder->DoTerminate(png_ptr, TerminalState::SUCCESS);
 657   }
 658
 659   if (decoder->mInProfile && decoder->GetCMSOutputProfile()) {
 660     qcms_data_type inType;
 661     qcms_data_type outType;
 662
 663     uint32_t profileSpace = qcms_profile_get_color_space(decoder->mInProfile);
 664     decoder->mUsePipeTransform = profileSpace != icSigGrayData;
 665     if (decoder->mUsePipeTransform) {
 666       // If the transform happens with SurfacePipe, it will be in RGBA if we
 667       // have an alpha channel, because the swizzle and premultiplication
 668       // happens after color management. Otherwise it will be in BGRA because
 669       // the swizzle happens at the start.
 670       if (transparency == TransparencyType::eAlpha) {
 671         inType = QCMS_DATA_RGBA_8;
 672         outType = QCMS_DATA_RGBA_8;
 673       } else {
 674         inType = gfxPlatform::GetCMSOSRGBAType();
 675         outType = inType;
 676       }
 677     } else {
 678       if (color_type & PNG_COLOR_MASK_ALPHA) {
 679         inType = QCMS_DATA_GRAYA_8;
 680         outType = gfxPlatform::GetCMSOSRGBAType();
 681       } else {
 682         inType = QCMS_DATA_GRAY_8;
 683         outType = gfxPlatform::GetCMSOSRGBAType();
 684       }
 685     }
 686
 687     decoder->mTransform = qcms_transform_create(decoder->mInProfile, inType,
 688                                                 decoder->GetCMSOutputProfile(),
 689                                                 outType, (qcms_intent)intent);
 690   } else if ((sRGBTag && decoder->mCMSMode == CMSMode::TaggedOnly) ||
 691              decoder->mCMSMode == CMSMode::All) {
 692     // If the transform happens with SurfacePipe, it will be in RGBA if we
 693     // have an alpha channel, because the swizzle and premultiplication
 694     // happens after color management. Otherwise it will be in OS_RGBA because
 695     // the swizzle happens at the start.
 696     if (transparency == TransparencyType::eAlpha) {
 697       decoder->mTransform =
 698           decoder->GetCMSsRGBTransform(SurfaceFormat::R8G8B8A8);
 699     } else {
 700       decoder->mTransform =
 701           decoder->GetCMSsRGBTransform(SurfaceFormat::OS_RGBA);
 702     }
 703     decoder->mUsePipeTransform = true;
 704   }
 705
 706 #ifdef PNG_APNG_SUPPORTED
 707   if (isAnimated) {
 708     png_set_progressive_frame_fn(png_ptr, nsPNGDecoder::frame_info_callback,
 709                                  nullptr);
 710   }
 711
 712   if (png_get_first_frame_is_hidden(png_ptr, info_ptr)) {
 713     decoder->mFrameIsHidden = true;
 714   } else {
 715 #endif
 716     nsresult rv = decoder->CreateFrame(FrameInfo{frameRect, isInterlaced});
 717     if (NS_FAILED(rv)) {
 718       png_error(decoder->mPNG, "CreateFrame failed");
 719     }
 720     MOZ_ASSERT(decoder->mImageData, "Should have a buffer now");
 721 #ifdef PNG_APNG_SUPPORTED
 722   }
 723 #endif
 724
 725   if (decoder->mTransform && !decoder->mUsePipeTransform) {
 726     decoder->mCMSLine =
 727         static_cast<uint8_t*>(malloc(sizeof(uint32_t) * frameRect.Width()));
 728     if (!decoder->mCMSLine) {
 729       png_error(decoder->mPNG, "malloc of mCMSLine failed");
 730     }
 731   }
 732
 733   if (interlace_type == PNG_INTERLACE_ADAM7) {
 734     if (frameRect.Height() <
 735         INT32_MAX / (frameRect.Width() * int32_t(channels))) {
 736       const size_t bufferSize =
 737           channels * frameRect.Width() * frameRect.Height();
 738
 739       if (bufferSize > SurfaceCache::MaximumCapacity()) {
 740         png_error(decoder->mPNG, "Insufficient memory to deinterlace image");
 741       }
 742
 743       decoder->interlacebuf = static_cast<uint8_t*>(malloc(bufferSize));
 744     }
 745     if (!decoder->interlacebuf) {
 746       png_error(decoder->mPNG, "malloc of interlacebuf failed");
 747     }
 748   }
 749 }
 750
 751 void nsPNGDecoder::PostInvalidationIfNeeded() {
 752   Maybe<SurfaceInvalidRect> invalidRect = mPipe.TakeInvalidRect();
 753   if (!invalidRect) {
 754     return;
 755   }
 756
 757   PostInvalidation(invalidRect->mInputSpaceRect,
 758                    Some(invalidRect->mOutputSpaceRect));
 759 }
 760
 761 void nsPNGDecoder::row_callback(png_structp png_ptr, png_bytep new_row,
 762                                 png_uint_32 row_num, int pass) {
 763   /* libpng comments:
 764    *
 765    * This function is called for every row in the image.  If the
 766    * image is interlacing, and you turned on the interlace handler,
 767    * this function will be called for every row in every pass.
 768    * Some of these rows will not be changed from the previous pass.
 769    * When the row is not changed, the new_row variable will be
 770    * nullptr. The rows and passes are called in order, so you don't
 771    * really need the row_num and pass, but I'm supplying them
 772    * because it may make your life easier.
 773    *
 774    * For the non-nullptr rows of interlaced images, you must call
 775    * png_progressive_combine_row() passing in the row and the
 776    * old row.  You can call this function for nullptr rows (it will
 777    * just return) and for non-interlaced images (it just does the
 778    * memcpy for you) if it will make the code easier.  Thus, you
 779    * can just do this for all cases:
 780    *
 781    *    png_progressive_combine_row(png_ptr, old_row, new_row);
 782    *
 783    * where old_row is what was displayed for previous rows.  Note
 784    * that the first pass (pass == 0 really) will completely cover
 785    * the old row, so the rows do not have to be initialized.  After
 786    * the first pass (and only for interlaced images), you will have
 787    * to pass the current row, and the function will combine the
 788    * old row and the new row.
 789    */
 790   nsPNGDecoder* decoder =
 791       static_cast<nsPNGDecoder*>(png_get_progressive_ptr(png_ptr));
 792
 793   if (decoder->mFrameIsHidden) {
 794     return;  // Skip this frame.
 795   }
 796
 797   MOZ_ASSERT_IF(decoder->IsFirstFrameDecode(), decoder->mNumFrames == 0);
 798
 799   while (pass > decoder->mPass) {
 800     // Advance to the next pass. We may have to do this multiple times because
 801     // libpng will skip passes if the image is so small that no pixels have
 802     // changed on a given pass, but ADAM7InterpolatingFilter needs to be reset
 803     // once for every pass to perform interpolation properly.
 804     decoder->mPipe.ResetToFirstRow();
 805     decoder->mPass++;
 806   }
 807
 808   const png_uint_32 height =
 809       static_cast<png_uint_32>(decoder->mFrameRect.Height());
 810
 811   if (row_num >= height) {
 812     // Bail if we receive extra rows. This is especially important because if we
 813     // didn't, we might overflow the deinterlacing buffer.
 814     MOZ_ASSERT_UNREACHABLE("libpng producing extra rows?");
 815     return;
 816   }
 817
 818   // Note that |new_row| may be null here, indicating that this is an interlaced
 819   // image and |row_callback| is being called for a row that hasn't changed.
 820   MOZ_ASSERT_IF(!new_row, decoder->interlacebuf);
 821
 822   if (decoder->interlacebuf) {
 823     uint32_t width = uint32_t(decoder->mFrameRect.Width());
 824
 825     // We'll output the deinterlaced version of the row.
 826     uint8_t* rowToWrite =
 827         decoder->interlacebuf + (row_num * decoder->mChannels * width);
 828
 829     // Update the deinterlaced version of this row with the new data.
 830     png_progressive_combine_row(png_ptr, rowToWrite, new_row);
 831
 832     decoder->WriteRow(rowToWrite);
 833   } else {
 834     decoder->WriteRow(new_row);
 835   }
 836 }
 837
 838 void nsPNGDecoder::WriteRow(uint8_t* aRow) {
 839   MOZ_ASSERT(aRow);
 840
 841   uint8_t* rowToWrite = aRow;
 842   uint32_t width = uint32_t(mFrameRect.Width());
 843
 844   // Apply color management to the row, if necessary, before writing it out.
 845   // This is only needed for grayscale images.
 846   if (mTransform && !mUsePipeTransform) {
 847     MOZ_ASSERT(mCMSLine);
 848     qcms_transform_data(mTransform, rowToWrite, mCMSLine, width);
 849     rowToWrite = mCMSLine;
 850   }
 851
 852   // Write this row to the SurfacePipe.
 853   DebugOnly<WriteState> result =
 854       mPipe.WriteBuffer(reinterpret_cast<uint32_t*>(rowToWrite));
 855   MOZ_ASSERT(WriteState(result) != WriteState::FAILURE);
 856
 857   PostInvalidationIfNeeded();
 858 }
 859
 860 void nsPNGDecoder::DoTerminate(png_structp aPNGStruct, TerminalState aState) {
 861   // Stop processing data. Note that we intentionally ignore the return value of
 862   // png_process_data_pause(), which tells us how many bytes of the data that
 863   // was passed to png_process_data() have not been consumed yet, because now
 864   // that we've reached a terminal state, we won't do any more decoding or call
 865   // back into libpng anymore.
 866   png_process_data_pause(aPNGStruct, /* save = */ false);
 867
 868   mNextTransition = aState == TerminalState::SUCCESS
 869                         ? Transition::TerminateSuccess()
 870                         : Transition::TerminateFailure();
 871 }
 872
 873 void nsPNGDecoder::DoYield(png_structp aPNGStruct) {
 874   // Pause data processing. png_process_data_pause() returns how many bytes of
 875   // the data that was passed to png_process_data() have not been consumed yet.
 876   // We use this information to tell StreamingLexer where to place us in the
 877   // input stream when we come back from the yield.
 878   png_size_t pendingBytes = png_process_data_pause(aPNGStruct,
 879                                                    /* save = */ false);
 880
 881   MOZ_ASSERT(pendingBytes < mLastChunkLength);
 882   size_t consumedBytes = mLastChunkLength - min(pendingBytes, mLastChunkLength);
 883
 884   mNextTransition =
 885       Transition::ContinueUnbufferedAfterYield(State::PNG_DATA, consumedBytes);
 886 }
 887
 888 nsresult nsPNGDecoder::FinishInternal() {
 889   // We shouldn't be called in error cases.
 890   MOZ_ASSERT(!HasError(), "Can't call FinishInternal on error!");
 891
 892   if (IsMetadataDecode()) {
 893     return NS_OK;
 894   }
 895
 896   int32_t loop_count = 0;
 897 #ifdef PNG_APNG_SUPPORTED
 898   if (png_get_valid(mPNG, mInfo, PNG_INFO_acTL)) {
 899     int32_t num_plays = png_get_num_plays(mPNG, mInfo);
 900     loop_count = num_plays - 1;
 901   }
 902 #endif
 903
 904   if (InFrame()) {
 905     EndImageFrame();
 906   }
 907   PostDecodeDone(loop_count);
 908
 909   return NS_OK;
 910 }
 911
 912 #ifdef PNG_APNG_SUPPORTED
 913 // got the header of a new frame that's coming
 914 void nsPNGDecoder::frame_info_callback(png_structp png_ptr,
 915                                        png_uint_32 frame_num) {
 916   nsPNGDecoder* decoder =
 917       static_cast<nsPNGDecoder*>(png_get_progressive_ptr(png_ptr));
 918
 919   // old frame is done
 920   decoder->EndImageFrame();
 921
 922   const bool previousFrameWasHidden = decoder->mFrameIsHidden;
 923
 924   if (!previousFrameWasHidden && decoder->IsFirstFrameDecode()) {
 925     // We're about to get a second non-hidden frame, but we only want the first.
 926     // Stop decoding now. (And avoid allocating the unnecessary buffers below.)
 927     return decoder->DoTerminate(png_ptr, TerminalState::SUCCESS);
 928   }
 929
 930   // Only the first frame can be hidden, so unhide unconditionally here.
 931   decoder->mFrameIsHidden = false;
 932
 933   // Save the information necessary to create the frame; we'll actually create
 934   // it when we return from the yield.
 935   const OrientedIntRect frameRect(
 936       png_get_next_frame_x_offset(png_ptr, decoder->mInfo),
 937       png_get_next_frame_y_offset(png_ptr, decoder->mInfo),
 938       png_get_next_frame_width(png_ptr, decoder->mInfo),
 939       png_get_next_frame_height(png_ptr, decoder->mInfo));
 940   const bool isInterlaced = bool(decoder->interlacebuf);
 941
 942 #  ifndef MOZ_EMBEDDED_LIBPNG
 943   // if using system library, check frame_width and height against 0
 944   if (frameRect.width == 0) {
 945     png_error(png_ptr, "Frame width must not be 0");
 946   }
 947   if (frameRect.height == 0) {
 948     png_error(png_ptr, "Frame height must not be 0");
 949   }
 950 #  endif
 951
 952   const FrameInfo info{frameRect, isInterlaced};
 953
 954   // If the previous frame was hidden, skip the yield (which will mislead the
 955   // caller, who will think the previous frame was real) and just allocate the
 956   // new frame here.
 957   if (previousFrameWasHidden) {
 958     if (NS_FAILED(decoder->CreateFrame(info))) {
 959       return decoder->DoTerminate(png_ptr, TerminalState::FAILURE);
 960     }
 961
 962     MOZ_ASSERT(decoder->mImageData, "Should have a buffer now");
 963     return;  // No yield, so we'll just keep decoding.
 964   }
 965
 966   // Yield to the caller to notify them that the previous frame is now complete.
 967   decoder->mNextFrameInfo = Some(info);
 968   return decoder->DoYield(png_ptr);
 969 }
 970 #endif
 971
 972 void nsPNGDecoder::end_callback(png_structp png_ptr, png_infop info_ptr) {
 973   /* libpng comments:
 974    *
 975    * this function is called when the whole image has been read,
 976    * including any chunks after the image (up to and including
 977    * the IEND).  You will usually have the same info chunk as you
 978    * had in the header, although some data may have been added
 979    * to the comments and time fields.
 980    *
 981    * Most people won't do much here, perhaps setting a flag that
 982    * marks the image as finished.
 983    */
 984
 985   nsPNGDecoder* decoder =
 986       static_cast<nsPNGDecoder*>(png_get_progressive_ptr(png_ptr));
 987
 988   // We shouldn't get here if we've hit an error
 989   MOZ_ASSERT(!decoder->HasError(), "Finishing up PNG but hit error!");
 990
 991   return decoder->DoTerminate(png_ptr, TerminalState::SUCCESS);
 992 }
 993
 994 void nsPNGDecoder::error_callback(png_structp png_ptr,
 995                                   png_const_charp error_msg) {
 996   MOZ_LOG(sPNGLog, LogLevel::Error, ("libpng error: %s\n", error_msg));
 997
 998   nsPNGDecoder* decoder =
 999       static_cast<nsPNGDecoder*>(png_get_progressive_ptr(png_ptr));
1000
1001   if (strstr(error_msg, "invalid chunk type")) {
1002     decoder->mErrorIsRecoverable = true;
1003   } else {
1004     decoder->mErrorIsRecoverable = false;
1005   }
1006
1007   png_longjmp(png_ptr, 1);
1008 }
1009
1010 void nsPNGDecoder::warning_callback(png_structp png_ptr,
1011                                     png_const_charp warning_msg) {
1012   MOZ_LOG(sPNGLog, LogLevel::Warning, ("libpng warning: %s\n", warning_msg));
1013 }
1014
1015 Maybe<Telemetry::HistogramID> nsPNGDecoder::SpeedHistogram() const {
1016   return Some(Telemetry::IMAGE_DECODE_SPEED_PNG);
1017 }
1018
1019 bool nsPNGDecoder::IsValidICOResource() const {
1020   // Only 32-bit RGBA PNGs are valid ICO resources; see here:
1021   //   http://blogs.msdn.com/b/oldnewthing/archive/2010/10/22/10079192.aspx
1022
1023   // If there are errors in the call to png_get_IHDR, the error_callback in
1024   // nsPNGDecoder.cpp is called.  In this error callback we do a longjmp, so
1025   // we need to save the jump buffer here. Otherwise we'll end up without a
1026   // proper callstack.
1027   if (setjmp(png_jmpbuf(mPNG))) {
1028     // We got here from a longjmp call indirectly from png_get_IHDR via
1029     // error_callback. Ignore mErrorIsRecoverable: if we got an invalid chunk
1030     // error before even reading the IHDR we can't recover from that.
1031     return false;
1032   }
1033
1034   png_uint_32 png_width,  // Unused
1035       png_height;         // Unused
1036
1037   int png_bit_depth, png_color_type;
1038
1039   if (png_get_IHDR(mPNG, mInfo, &png_width, &png_height, &png_bit_depth,
1040                    &png_color_type, nullptr, nullptr, nullptr)) {
1041     return ((png_color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
1042              png_color_type == PNG_COLOR_TYPE_RGB) &&
1043             png_bit_depth == 8);
1044   } else {
1045     return false;
1046   }
1047 }
1048
1049 }  // namespace image
1050 }  // namespace mozilla