Clean up some image decoder classes:

- Use std::vector<uint8_t> instead of raw uint8_t*
- Make ICodec_ScanlineDecoder::GetScanline() return const uint8_t*
- Add FxFreeDeleter, use it in CCodec_ImageDataCache.
- Make CCodec_ImageDataCache encapsulate its data members.

R=tsepez@chromium.org

Review URL: https://codereview.chromium.org/1361053002 .

2 files changed, 14 insertions, 23 deletions

diff --git a/core/src/fpdfapi/fpdf_page/fpdf_page_parser_old.cpp b/core/src/fpdfapi/fpdf_page/fpdf_page_parser_old.cpp
index c9bcff6db6..ace7bf925b 100644
--- a/core/src/fpdfapi/fpdf_page/fpdf_page_parser_old.cpp
+++ b/core/src/fpdfapi/fpdf_page/fpdf_page_parser_old.cpp
@@ -247,10 +247,10 @@ FX_DWORD _DecodeAllScanlines(ICodec_ScanlineDecoder* pDecoder,
   dest_buf = FX_Alloc2D(uint8_t, pitch, height);
   dest_size = pitch * height;  // Safe since checked alloc returned.
   for (int row = 0; row < height; row++) {
-    uint8_t* pLine = pDecoder->GetScanline(row);
-    if (pLine == NULL) {
+    const uint8_t* pLine = pDecoder->GetScanline(row);
+    if (!pLine)
       break;
-    }
+
     FXSYS_memcpy(dest_buf + row * pitch, pLine, pitch);
   }
   FX_DWORD srcoff = pDecoder->GetSrcOffset();
diff --git a/core/src/fpdfapi/fpdf_render/fpdf_render_loadimage.cpp b/core/src/fpdfapi/fpdf_render/fpdf_render_loadimage.cpp
index 9497943fbd..f1fbf41d6d 100644
--- a/core/src/fpdfapi/fpdf_render/fpdf_render_loadimage.cpp
+++ b/core/src/fpdfapi/fpdf_render/fpdf_render_loadimage.cpp
@@ -4,6 +4,8 @@
 
 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
 
+#include <vector>
+
 #include "../../../../third_party/base/nonstd_unique_ptr.h"
 #include "../../../include/fpdfapi/fpdf_module.h"
 #include "../../../include/fpdfapi/fpdf_pageobj.h"
@@ -57,15 +59,13 @@ FX_SAFE_DWORD CalculatePitch32(int bpp, int width) {
   return pitch;
 }
 
-// Wrapper class to hold objects allocated in CPDF_DIBSource::LoadJpxBitmap(),
-// because nonstd::unique_ptr does not support custom deleters yet.
+// Wrapper class to use with nonstd::unique_ptr for CJPX_Decoder.
 class JpxBitMapContext {
  public:
   explicit JpxBitMapContext(ICodec_JpxModule* jpx_module)
-      : jpx_module_(jpx_module), decoder_(nullptr), output_offsets_(nullptr) {}
+      : jpx_module_(jpx_module), decoder_(nullptr) {}
 
   ~JpxBitMapContext() {
-    FX_Free(output_offsets_);
     jpx_module_->DestroyDecoder(decoder_);
   }
 
@@ -74,17 +74,9 @@ class JpxBitMapContext {
 
   CJPX_Decoder* decoder() { return decoder_; }
 
-  // Takes ownership of |output_offsets|.
-  void set_output_offsets(unsigned char* output_offsets) {
-    output_offsets_ = output_offsets;
-  }
-
-  unsigned char* output_offsets() { return output_offsets_; }
-
  private:
-  ICodec_JpxModule* jpx_module_;   // Weak pointer.
-  CJPX_Decoder* decoder_;          // Decoder, owned.
-  unsigned char* output_offsets_;  // Output offsets for decoding, owned.
+  ICodec_JpxModule* const jpx_module_;  // Weak pointer.
+  CJPX_Decoder* decoder_;               // Decoder, owned.
 
   // Disallow evil constructors
   JpxBitMapContext(const JpxBitMapContext&);
@@ -747,16 +739,15 @@ void CPDF_DIBSource::LoadJpxBitmap() {
     return;
   }
   m_pCachedBitmap->Clear(0xFFFFFFFF);
-  context->set_output_offsets(FX_Alloc(uint8_t, components));
+  std::vector<uint8_t> output_offsets(components);
   for (int i = 0; i < components; ++i)
-    context->output_offsets()[i] = i;
+    output_offsets[i] = i;
   if (bSwapRGB) {
-    context->output_offsets()[0] = 2;
-    context->output_offsets()[2] = 0;
+    output_offsets[0] = 2;
+    output_offsets[2] = 0;
   }
   if (!pJpxModule->Decode(context->decoder(), m_pCachedBitmap->GetBuffer(),
-                          m_pCachedBitmap->GetPitch(),
-                          context->output_offsets())) {
+                          m_pCachedBitmap->GetPitch(), output_offsets)) {
     m_pCachedBitmap.reset();
     return;
   }