Move format specific elements out of StartDecodechromium/3324

Refactoring the big image format switch in StartDecode to call
separate methods for each image format, instead of having one giant
switch block. This should have no functional changes.

BUG=pdfium:976

Change-Id: I4e609ecaec0c5d0e173957c0795555b37c38f9a2
Reviewed-on: https://pdfium-review.googlesource.com/23131
Commit-Queue: Ryan Harrison <rharrison@chromium.org>
Reviewed-by: dsinclair <dsinclair@chromium.org>

2 files changed, 156 insertions, 136 deletions

diff --git a/core/fxcodec/codec/ccodec_progressivedecoder.h b/core/fxcodec/codec/ccodec_progressivedecoder.h
index 83ccce2f6c..de2cd3ced6 100644
--- a/core/fxcodec/codec/ccodec_progressivedecoder.h
+++ b/core/fxcodec/codec/ccodec_progressivedecoder.h
@@ -190,6 +190,11 @@ class CCodec_ProgressiveDecoder : public CCodec_BmpModule::Delegate,
                                  double scale_y,
                                  int des_row);
 
+  FXCODEC_STATUS JpegStartDecode(const RetainPtr<CFX_DIBitmap>& pDIBitmap);
+  FXCODEC_STATUS PngStartDecode(const RetainPtr<CFX_DIBitmap>& pDIBitmap);
+  FXCODEC_STATUS GifStartDecode(const RetainPtr<CFX_DIBitmap>& pDIBitmap);
+  FXCODEC_STATUS BmpStartDecode(const RetainPtr<CFX_DIBitmap>& pDIBitmap);
+
   RetainPtr<IFX_SeekableReadStream> m_pFile;
   RetainPtr<CFX_DIBitmap> m_pDeviceBitmap;
   UnownedPtr<CCodec_ModuleMgr> m_pCodecMgr;
diff --git a/core/fxcodec/codec/fx_codec_progress.cpp b/core/fxcodec/codec/fx_codec_progress.cpp
index 1b8da15b68..277d92c0ed 100644
--- a/core/fxcodec/codec/fx_codec_progress.cpp
+++ b/core/fxcodec/codec/fx_codec_progress.cpp
@@ -1899,149 +1899,164 @@ FXCODEC_STATUS CCodec_ProgressiveDecoder::StartDecode(
     return FXCODEC_STATUS_ERR_PARAMS;
   }
   switch (m_imagType) {
-    case FXCODEC_IMAGE_JPG: {
-      int down_scale = 1;
-      GetDownScale(down_scale);
-      // Setting jump marker before calling StartScanLine, since a longjmp to
-      // the marker indicates a fatal error.
-      if (setjmp(*m_pJpegContext->GetJumpMark()) == -1) {
-        m_pJpegContext.reset();
-        m_status = FXCODEC_STATUS_ERROR;
-        return FXCODEC_STATUS_ERROR;
-      }
-
-      CCodec_JpegModule* pJpegModule = m_pCodecMgr->GetJpegModule();
-      bool startStatus =
-          pJpegModule->StartScanline(m_pJpegContext.get(), down_scale);
-      while (!startStatus) {
-        FXCODEC_STATUS error_status = FXCODEC_STATUS_ERROR;
-        if (!JpegReadMoreData(pJpegModule, error_status)) {
-          m_pDeviceBitmap = nullptr;
-          m_pFile = nullptr;
-          m_status = error_status;
-          return m_status;
-        }
-
-        startStatus =
-            pJpegModule->StartScanline(m_pJpegContext.get(), down_scale);
-      }
-      int scanline_size = (m_SrcWidth + down_scale - 1) / down_scale;
-      scanline_size = (scanline_size * m_SrcComponents + 3) / 4 * 4;
-      FX_Free(m_pDecodeBuf);
-      m_pDecodeBuf = FX_Alloc(uint8_t, scanline_size);
-      memset(m_pDecodeBuf, 0, scanline_size);
-      m_WeightHorz.Calc(m_sizeX, 0, m_sizeX, m_clipBox.Width(), 0,
-                        m_clipBox.Width());
-      m_WeightVert.Calc(m_sizeY, m_clipBox.Height());
-      switch (m_SrcComponents) {
-        case 1:
-          m_SrcFormat = FXCodec_8bppGray;
-          break;
-        case 3:
-          m_SrcFormat = FXCodec_Rgb;
-          break;
-        case 4:
-          m_SrcFormat = FXCodec_Cmyk;
-          break;
-      }
-      GetTransMethod(pDIBitmap->GetFormat(), m_SrcFormat);
-      m_status = FXCODEC_STATUS_DECODE_TOBECONTINUE;
-      return m_status;
-    }
-    case FXCODEC_IMAGE_PNG: {
-      CCodec_PngModule* pPngModule = m_pCodecMgr->GetPngModule();
-      if (!pPngModule) {
-        m_pDeviceBitmap = nullptr;
-        m_pFile = nullptr;
-        m_status = FXCODEC_STATUS_ERR_MEMORY;
-        return m_status;
-      }
-      m_pPngContext = pPngModule->Start(this);
-      if (!m_pPngContext) {
-        m_pDeviceBitmap = nullptr;
-        m_pFile = nullptr;
-        m_status = FXCODEC_STATUS_ERR_MEMORY;
-        return m_status;
-      }
-      m_offSet = 0;
-      switch (m_pDeviceBitmap->GetFormat()) {
-        case FXDIB_8bppMask:
-        case FXDIB_8bppRgb:
-          m_SrcComponents = 1;
-          m_SrcFormat = FXCodec_8bppGray;
-          break;
-        case FXDIB_Rgb:
-          m_SrcComponents = 3;
-          m_SrcFormat = FXCodec_Rgb;
-          break;
-        case FXDIB_Rgb32:
-        case FXDIB_Argb:
-          m_SrcComponents = 4;
-          m_SrcFormat = FXCodec_Argb;
-          break;
-        default: {
-          m_pDeviceBitmap = nullptr;
-          m_pFile = nullptr;
-          m_status = FXCODEC_STATUS_ERR_PARAMS;
-          return m_status;
-        }
-      }
-      GetTransMethod(m_pDeviceBitmap->GetFormat(), m_SrcFormat);
-      int scanline_size = (m_SrcWidth * m_SrcComponents + 3) / 4 * 4;
-      FX_Free(m_pDecodeBuf);
-      m_pDecodeBuf = FX_Alloc(uint8_t, scanline_size);
-      memset(m_pDecodeBuf, 0, scanline_size);
-      m_WeightHorzOO.Calc(m_sizeX, m_clipBox.Width());
-      m_WeightVert.Calc(m_sizeY, m_clipBox.Height());
+    case FXCODEC_IMAGE_JPG:
+      return JpegStartDecode(pDIBitmap);
+    case FXCODEC_IMAGE_PNG:
+      return PngStartDecode(pDIBitmap);
+    case FXCODEC_IMAGE_GIF:
+      return GifStartDecode(pDIBitmap);
+    case FXCODEC_IMAGE_BMP:
+      return BmpStartDecode(pDIBitmap);
+    case FXCODEC_IMAGE_TIF:
       m_status = FXCODEC_STATUS_DECODE_TOBECONTINUE;
       return m_status;
-    }
-    case FXCODEC_IMAGE_GIF: {
-      CCodec_GifModule* pGifModule = m_pCodecMgr->GetGifModule();
-      if (!pGifModule) {
-        m_pDeviceBitmap = nullptr;
-        m_pFile = nullptr;
-        m_status = FXCODEC_STATUS_ERR_MEMORY;
-        return m_status;
-      }
-      m_SrcFormat = FXCodec_8bppRgb;
-      GetTransMethod(m_pDeviceBitmap->GetFormat(), m_SrcFormat);
-      int scanline_size = (m_SrcWidth + 3) / 4 * 4;
-      FX_Free(m_pDecodeBuf);
-      m_pDecodeBuf = FX_Alloc(uint8_t, scanline_size);
-      memset(m_pDecodeBuf, 0, scanline_size);
-      m_WeightHorz.Calc(m_sizeX, 0, m_sizeX, m_clipBox.Width(), 0,
-                        m_clipBox.Width());
-      m_WeightVert.Calc(m_sizeY, m_clipBox.Height());
-      m_FrameCur = 0;
-      m_status = FXCODEC_STATUS_DECODE_TOBECONTINUE;
+    default:
+      return FXCODEC_STATUS_ERROR;
+  }
+}
+
+FXCODEC_STATUS CCodec_ProgressiveDecoder::JpegStartDecode(
+    const RetainPtr<CFX_DIBitmap>& pDIBitmap) {
+  int down_scale = 1;
+  GetDownScale(down_scale);
+  // Setting jump marker before calling StartScanLine, since a longjmp to
+  // the marker indicates a fatal error.
+  if (setjmp(*m_pJpegContext->GetJumpMark()) == -1) {
+    m_pJpegContext.reset();
+    m_status = FXCODEC_STATUS_ERROR;
+    return FXCODEC_STATUS_ERROR;
+  }
+
+  CCodec_JpegModule* pJpegModule = m_pCodecMgr->GetJpegModule();
+  bool startStatus =
+      pJpegModule->StartScanline(m_pJpegContext.get(), down_scale);
+  while (!startStatus) {
+    FXCODEC_STATUS error_status = FXCODEC_STATUS_ERROR;
+    if (!JpegReadMoreData(pJpegModule, error_status)) {
+      m_pDeviceBitmap = nullptr;
+      m_pFile = nullptr;
+      m_status = error_status;
       return m_status;
     }
-    case FXCODEC_IMAGE_BMP: {
-      CCodec_BmpModule* pBmpModule = m_pCodecMgr->GetBmpModule();
-      if (!pBmpModule) {
-        m_pDeviceBitmap = nullptr;
-        m_pFile = nullptr;
-        m_status = FXCODEC_STATUS_ERR_MEMORY;
-        return m_status;
-      }
-      GetTransMethod(m_pDeviceBitmap->GetFormat(), m_SrcFormat);
-      m_ScanlineSize = (m_SrcWidth * m_SrcComponents + 3) / 4 * 4;
-      FX_Free(m_pDecodeBuf);
-      m_pDecodeBuf = FX_Alloc(uint8_t, m_ScanlineSize);
-      memset(m_pDecodeBuf, 0, m_ScanlineSize);
-      m_WeightHorz.Calc(m_sizeX, 0, m_sizeX, m_clipBox.Width(), 0,
-                        m_clipBox.Width());
-      m_WeightVert.Calc(m_sizeY, m_clipBox.Height());
-      m_status = FXCODEC_STATUS_DECODE_TOBECONTINUE;
+
+    startStatus = pJpegModule->StartScanline(m_pJpegContext.get(), down_scale);
+  }
+  int scanline_size = (m_SrcWidth + down_scale - 1) / down_scale;
+  scanline_size = (scanline_size * m_SrcComponents + 3) / 4 * 4;
+  FX_Free(m_pDecodeBuf);
+  m_pDecodeBuf = FX_Alloc(uint8_t, scanline_size);
+  memset(m_pDecodeBuf, 0, scanline_size);
+  m_WeightHorz.Calc(m_sizeX, 0, m_sizeX, m_clipBox.Width(), 0,
+                    m_clipBox.Width());
+  m_WeightVert.Calc(m_sizeY, m_clipBox.Height());
+  switch (m_SrcComponents) {
+    case 1:
+      m_SrcFormat = FXCodec_8bppGray;
+      break;
+    case 3:
+      m_SrcFormat = FXCodec_Rgb;
+      break;
+    case 4:
+      m_SrcFormat = FXCodec_Cmyk;
+      break;
+  }
+  GetTransMethod(pDIBitmap->GetFormat(), m_SrcFormat);
+  m_status = FXCODEC_STATUS_DECODE_TOBECONTINUE;
+  return m_status;
+}
+
+FXCODEC_STATUS CCodec_ProgressiveDecoder::PngStartDecode(
+    const RetainPtr<CFX_DIBitmap>& pDIBitmap) {
+  CCodec_PngModule* pPngModule = m_pCodecMgr->GetPngModule();
+  if (!pPngModule) {
+    m_pDeviceBitmap = nullptr;
+    m_pFile = nullptr;
+    m_status = FXCODEC_STATUS_ERR_MEMORY;
+    return m_status;
+  }
+  m_pPngContext = pPngModule->Start(this);
+  if (!m_pPngContext) {
+    m_pDeviceBitmap = nullptr;
+    m_pFile = nullptr;
+    m_status = FXCODEC_STATUS_ERR_MEMORY;
+    return m_status;
+  }
+  m_offSet = 0;
+  switch (m_pDeviceBitmap->GetFormat()) {
+    case FXDIB_8bppMask:
+    case FXDIB_8bppRgb:
+      m_SrcComponents = 1;
+      m_SrcFormat = FXCodec_8bppGray;
+      break;
+    case FXDIB_Rgb:
+      m_SrcComponents = 3;
+      m_SrcFormat = FXCodec_Rgb;
+      break;
+    case FXDIB_Rgb32:
+    case FXDIB_Argb:
+      m_SrcComponents = 4;
+      m_SrcFormat = FXCodec_Argb;
+      break;
+    default: {
+      m_pDeviceBitmap = nullptr;
+      m_pFile = nullptr;
+      m_status = FXCODEC_STATUS_ERR_PARAMS;
       return m_status;
     }
-    case FXCODEC_IMAGE_TIF:
-      m_status = FXCODEC_STATUS_DECODE_TOBECONTINUE;
-      return m_status;
-    default:
-      return FXCODEC_STATUS_ERROR;
   }
+  GetTransMethod(m_pDeviceBitmap->GetFormat(), m_SrcFormat);
+  int scanline_size = (m_SrcWidth * m_SrcComponents + 3) / 4 * 4;
+  FX_Free(m_pDecodeBuf);
+  m_pDecodeBuf = FX_Alloc(uint8_t, scanline_size);
+  memset(m_pDecodeBuf, 0, scanline_size);
+  m_WeightHorzOO.Calc(m_sizeX, m_clipBox.Width());
+  m_WeightVert.Calc(m_sizeY, m_clipBox.Height());
+  m_status = FXCODEC_STATUS_DECODE_TOBECONTINUE;
+  return m_status;
+}
+
+FXCODEC_STATUS CCodec_ProgressiveDecoder::GifStartDecode(
+    const RetainPtr<CFX_DIBitmap>& pDIBitmap) {
+  CCodec_GifModule* pGifModule = m_pCodecMgr->GetGifModule();
+  if (!pGifModule) {
+    m_pDeviceBitmap = nullptr;
+    m_pFile = nullptr;
+    m_status = FXCODEC_STATUS_ERR_MEMORY;
+    return m_status;
+  }
+  m_SrcFormat = FXCodec_8bppRgb;
+  GetTransMethod(m_pDeviceBitmap->GetFormat(), m_SrcFormat);
+  int scanline_size = (m_SrcWidth + 3) / 4 * 4;
+  FX_Free(m_pDecodeBuf);
+  m_pDecodeBuf = FX_Alloc(uint8_t, scanline_size);
+  memset(m_pDecodeBuf, 0, scanline_size);
+  m_WeightHorz.Calc(m_sizeX, 0, m_sizeX, m_clipBox.Width(), 0,
+                    m_clipBox.Width());
+  m_WeightVert.Calc(m_sizeY, m_clipBox.Height());
+  m_FrameCur = 0;
+  m_status = FXCODEC_STATUS_DECODE_TOBECONTINUE;
+  return m_status;
+}
+
+FXCODEC_STATUS CCodec_ProgressiveDecoder::BmpStartDecode(
+    const RetainPtr<CFX_DIBitmap>& pDIBitmap) {
+  CCodec_BmpModule* pBmpModule = m_pCodecMgr->GetBmpModule();
+  if (!pBmpModule) {
+    m_pDeviceBitmap = nullptr;
+    m_pFile = nullptr;
+    m_status = FXCODEC_STATUS_ERR_MEMORY;
+    return m_status;
+  }
+  GetTransMethod(m_pDeviceBitmap->GetFormat(), m_SrcFormat);
+  m_ScanlineSize = (m_SrcWidth * m_SrcComponents + 3) / 4 * 4;
+  FX_Free(m_pDecodeBuf);
+  m_pDecodeBuf = FX_Alloc(uint8_t, m_ScanlineSize);
+  memset(m_pDecodeBuf, 0, m_ScanlineSize);
+  m_WeightHorz.Calc(m_sizeX, 0, m_sizeX, m_clipBox.Width(), 0,
+                    m_clipBox.Width());
+  m_WeightVert.Calc(m_sizeY, m_clipBox.Height());
+  m_status = FXCODEC_STATUS_DECODE_TOBECONTINUE;
+  return m_status;
 }
 
 FXCODEC_STATUS CCodec_ProgressiveDecoder::ContinueDecode() {