Move CCodec_GifModule state to CGifContext

Introduce a base CCodec_GifModule::Context class with a virtual
destructor so holders of unique_ptr's to these can delete them
without actually having any knowledge of the implementation
details of the context.

Bug: 728669
Change-Id: Ia50f94300924a1053c326984eac3b03f25f1b83c
Reviewed-on: https://pdfium-review.googlesource.com/6190
Commit-Queue: Tom Sepez <tsepez@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>

3 files changed, 21 insertions, 20 deletions

diff --git a/core/fxcodec/lgif/cgifcontext.cpp b/core/fxcodec/lgif/cgifcontext.cpp
index 9c03cffa21..e57e978218 100644
--- a/core/fxcodec/lgif/cgifcontext.cpp
+++ b/core/fxcodec/lgif/cgifcontext.cpp
@@ -13,15 +13,16 @@
 #include "third_party/base/ptr_util.h"
 #include "third_party/base/stl_util.h"
 
-CGifContext::CGifContext(CCodec_GifModule* gif_module, char* error_string)
-    : global_pal_num(0),
+CGifContext::CGifContext(CCodec_GifModule* gif_module,
+                         CCodec_GifModule::Delegate* pDelegate)
+    : m_pModule(gif_module),
+      m_pDelegate(pDelegate),
+      global_pal_num(0),
       img_row_offset(0),
       img_row_avail_size(0),
       avail_in(0),
       decode_status(GIF_D_STATUS_SIG),
       skip_size(0),
-      m_Module(gif_module),
-      err_ptr(error_string),
       next_in(nullptr),
       width(0),
       height(0),
@@ -29,20 +30,22 @@ CGifContext::CGifContext(CCodec_GifModule* gif_module, char* error_string)
       pixel_aspect(0),
       global_sort_flag(0),
       global_color_resolution(0),
-      img_pass_num(0) {}
+      img_pass_num(0) {
+  memset(m_szLastError, 0, sizeof(m_szLastError));
+}
 
 CGifContext::~CGifContext() {}
 
 void CGifContext::AddError(const char* err_msg) {
-  strncpy(err_ptr, err_msg, GIF_MAX_ERROR_SIZE - 1);
+  strncpy(m_szLastError, err_msg, GIF_MAX_ERROR_SIZE - 1);
 }
 
 void CGifContext::RecordCurrentPosition(uint32_t* cur_pos_ptr) {
-  m_Module->GetDelegate()->GifRecordCurrentPosition(*cur_pos_ptr);
+  m_pDelegate->GifRecordCurrentPosition(*cur_pos_ptr);
 }
 
 void CGifContext::ReadScanline(int32_t row_num, uint8_t* row_buf) {
-  m_Module->GetDelegate()->GifReadScanline(row_num, row_buf);
+  m_pDelegate->GifReadScanline(row_num, row_buf);
 }
 
 bool CGifContext::GetRecordPosition(uint32_t cur_pos,
@@ -57,7 +60,7 @@ bool CGifContext::GetRecordPosition(uint32_t cur_pos,
                                     int32_t trans_index,
                                     int32_t disposal_method,
                                     bool interlace) {
-  return m_Module->GetDelegate()->GifInputRecordPositionBuf(
+  return m_pDelegate->GifInputRecordPositionBuf(
       cur_pos, FX_RECT(left, top, left + width, top + height), pal_num, pal_ptr,
       delay_time, user_input, trans_index, disposal_method, interlace);
 }
diff --git a/core/fxcodec/lgif/cgifcontext.h b/core/fxcodec/lgif/cgifcontext.h
index 20d640ef35..fa46b14559 100644
--- a/core/fxcodec/lgif/cgifcontext.h
+++ b/core/fxcodec/lgif/cgifcontext.h
@@ -10,16 +10,16 @@
 #include <memory>
 #include <vector>
 
+#include "core/fxcodec/codec/ccodec_gifmodule.h"
 #include "core/fxcodec/lgif/fx_gif.h"
 #include "core/fxcrt/cfx_unowned_ptr.h"
 #include "core/fxcrt/fx_basic.h"
 
-class CCodec_GifModule;
-
-class CGifContext {
+class CGifContext : public CCodec_GifModule::Context {
  public:
-  CGifContext(CCodec_GifModule* gif_module, char* error_string);
-  ~CGifContext();
+  CGifContext(CCodec_GifModule* gif_module,
+              CCodec_GifModule::Delegate* pDelegate);
+  ~CGifContext() override;
 
   void AddError(const char* err_msg);
   void RecordCurrentPosition(uint32_t* cur_pos_ptr);
@@ -37,6 +37,8 @@ class CGifContext {
                          int32_t disposal_method,
                          bool interlace);
 
+  CFX_UnownedPtr<CCodec_GifModule> m_pModule;
+  CFX_UnownedPtr<CCodec_GifModule::Delegate> m_pDelegate;
   std::vector<GifPalette> m_GlobalPalette;
   int32_t global_pal_num;
   uint32_t img_row_offset;
@@ -44,23 +46,19 @@ class CGifContext {
   uint32_t avail_in;
   int32_t decode_status;
   uint32_t skip_size;
-
-  CFX_UnownedPtr<CCodec_GifModule> m_Module;
-  char* err_ptr;
   CFX_ByteString cmt_data;
   std::unique_ptr<GifGCE> m_GifGCE;
   uint8_t* next_in;
   std::vector<std::unique_ptr<GifImage>> m_Images;
   std::unique_ptr<CGifLZWDecoder> m_ImgDecoder;
-
   int width;
   int height;
-
   uint8_t bc_index;
   uint8_t pixel_aspect;
   uint8_t global_sort_flag;
   uint8_t global_color_resolution;
   uint8_t img_pass_num;
+  char m_szLastError[GIF_MAX_ERROR_SIZE];
 };
 
 #endif  // CORE_FXCODEC_LGIF_CGIFCONTEXT_H_
diff --git a/core/fxcodec/lgif/fx_gif.cpp b/core/fxcodec/lgif/fx_gif.cpp
index b4fe328f6c..cef4f9a9a5 100644
--- a/core/fxcodec/lgif/fx_gif.cpp
+++ b/core/fxcodec/lgif/fx_gif.cpp
@@ -565,7 +565,7 @@ GifDecodeStatus gif_load_frame(CGifContext* context, int32_t frame_num) {
     }
     if (!context->m_ImgDecoder.get())
       context->m_ImgDecoder =
-          pdfium::MakeUnique<CGifLZWDecoder>(context->err_ptr);
+          pdfium::MakeUnique<CGifLZWDecoder>(context->m_szLastError);
     context->m_ImgDecoder->InitTable(gif_image_ptr->image_code_size);
     context->img_row_offset = 0;
     context->img_row_avail_size = 0;