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