Remove longjmp from the Gif module

The Gif module is only using the longjmp as a way to catch errors, so this CL
makes it use GifDecodeStatus::Error instead.

Change-Id: I9c97e63ed851d2a80e38f1d2cd9e8f297d608cb2
Reviewed-on: https://pdfium-review.googlesource.com/5850
Commit-Queue: Nicolás Peña <npm@chromium.org>
Reviewed-by: Tom Sepez <tsepez@chromium.org>

5 files changed, 28 insertions, 52 deletions

diff --git a/core/fxcodec/codec/ccodec_gifmodule.cpp b/core/fxcodec/codec/ccodec_gifmodule.cpp
index 438f019ee9..11980ee7a5 100644
--- a/core/fxcodec/codec/ccodec_gifmodule.cpp
+++ b/core/fxcodec/codec/ccodec_gifmodule.cpp
@@ -30,9 +30,6 @@ GifDecodeStatus CCodec_GifModule::ReadHeader(CGifContext* context,
                                              void** pal_pp,
                                              int* bg_index,
                                              CFX_DIBAttribute* pAttribute) {
-  if (setjmp(context->jmpbuf))
-    return GifDecodeStatus::Error;
-
   GifDecodeStatus ret = gif_read_header(context);
   if (ret != GifDecodeStatus::Success)
     return ret;
@@ -48,9 +45,6 @@ GifDecodeStatus CCodec_GifModule::ReadHeader(CGifContext* context,
 
 GifDecodeStatus CCodec_GifModule::LoadFrameInfo(CGifContext* context,
                                                 int* frame_num) {
-  if (setjmp(context->jmpbuf))
-    return GifDecodeStatus::Error;
-
   GifDecodeStatus ret = gif_get_frame(context);
   if (ret != GifDecodeStatus::Success)
     return ret;
@@ -62,28 +56,24 @@ GifDecodeStatus CCodec_GifModule::LoadFrameInfo(CGifContext* context,
 GifDecodeStatus CCodec_GifModule::LoadFrame(CGifContext* context,
                                             int frame_num,
                                             CFX_DIBAttribute* pAttribute) {
-  if (setjmp(context->jmpbuf))
-    return GifDecodeStatus::Error;
-
   GifDecodeStatus ret = gif_load_frame(context, frame_num);
-  if (ret == GifDecodeStatus::Success) {
-    if (pAttribute) {
-      pAttribute->m_nGifLeft = context->m_Images[frame_num]->m_ImageInfo.left;
-      pAttribute->m_nGifTop = context->m_Images[frame_num]->m_ImageInfo.top;
-      pAttribute->m_fAspectRatio = context->pixel_aspect;
-      const uint8_t* buf =
-          reinterpret_cast<const uint8_t*>(context->cmt_data.GetBuffer(0));
-      uint32_t len = context->cmt_data.GetLength();
-      if (len > 21) {
-        uint8_t size = *buf++;
-        if (size != 0)
-          pAttribute->m_strAuthor = CFX_ByteString(buf, size);
-        else
-          pAttribute->m_strAuthor.clear();
-      }
-    }
+  if (ret != GifDecodeStatus::Success || !pAttribute)
+    return ret;
+
+  pAttribute->m_nGifLeft = context->m_Images[frame_num]->m_ImageInfo.left;
+  pAttribute->m_nGifTop = context->m_Images[frame_num]->m_ImageInfo.top;
+  pAttribute->m_fAspectRatio = context->pixel_aspect;
+  const uint8_t* buf =
+      reinterpret_cast<const uint8_t*>(context->cmt_data.GetBuffer(0));
+  uint32_t len = context->cmt_data.GetLength();
+  if (len > 21) {
+    uint8_t size = *buf++;
+    if (size != 0)
+      pAttribute->m_strAuthor = CFX_ByteString(buf, size);
+    else
+      pAttribute->m_strAuthor.clear();
   }
-  return ret;
+  return GifDecodeStatus::Success;
 }
 
 uint32_t CCodec_GifModule::GetAvailInput(CGifContext* context,
diff --git a/core/fxcodec/lgif/cgifcontext.cpp b/core/fxcodec/lgif/cgifcontext.cpp
index b7a513c7e8..9c03cffa21 100644
--- a/core/fxcodec/lgif/cgifcontext.cpp
+++ b/core/fxcodec/lgif/cgifcontext.cpp
@@ -33,9 +33,8 @@ CGifContext::CGifContext(CCodec_GifModule* gif_module, char* error_string)
 
 CGifContext::~CGifContext() {}
 
-void CGifContext::ThrowError(const char* err_msg) {
+void CGifContext::AddError(const char* err_msg) {
   strncpy(err_ptr, err_msg, GIF_MAX_ERROR_SIZE - 1);
-  longjmp(jmpbuf, 1);
 }
 
 void CGifContext::RecordCurrentPosition(uint32_t* cur_pos_ptr) {
diff --git a/core/fxcodec/lgif/cgifcontext.h b/core/fxcodec/lgif/cgifcontext.h
index e65d6c7b0b..08a66c18e2 100644
--- a/core/fxcodec/lgif/cgifcontext.h
+++ b/core/fxcodec/lgif/cgifcontext.h
@@ -7,7 +7,6 @@
 #ifndef CORE_FXCODEC_LGIF_CGIFCONTEXT_H_
 #define CORE_FXCODEC_LGIF_CGIFCONTEXT_H_
 
-#include <setjmp.h>
 #include <memory>
 #include <vector>
 
@@ -21,8 +20,7 @@ class CGifContext {
   CGifContext(CCodec_GifModule* gif_module, char* error_string);
   ~CGifContext();
 
-  // TODO(npm): Remove longjmp from this method!!!
-  void ThrowError(const char* err_msg);
+  void AddError(const char* err_msg);
   void RecordCurrentPosition(uint32_t* cur_pos_ptr);
   void ReadScanline(int32_t row_num, uint8_t* row_buf);
   bool GetRecordPosition(uint32_t cur_pos,
@@ -38,7 +36,6 @@ class CGifContext {
                          int32_t disposal_method,
                          bool interlace);
 
-  jmp_buf jmpbuf;
   std::vector<GifPalette> m_GlobalPalette;
   int32_t global_pal_num;
   uint32_t img_row_offset;
diff --git a/core/fxcodec/lgif/fx_gif.cpp b/core/fxcodec/lgif/fx_gif.cpp
index 5e257cc2f5..b4fe328f6c 100644
--- a/core/fxcodec/lgif/fx_gif.cpp
+++ b/core/fxcodec/lgif/fx_gif.cpp
@@ -119,8 +119,7 @@ GifDecodeStatus gif_decode_extension(CGifContext* context) {
 
 GifDecodeStatus gif_decode_image_info(CGifContext* context) {
   if (context->width == 0 || context->height == 0) {
-    context->ThrowError("No Image Header Info");
-    NOTREACHED();
+    context->AddError("No Image Header Info");
     return GifDecodeStatus::Error;
   }
   uint32_t skip_size_org = context->skip_size;
@@ -143,9 +142,7 @@ GifDecodeStatus gif_decode_image_info(CGifContext* context) {
           context->width ||
       gif_image->m_ImageInfo.top + gif_image->m_ImageInfo.height >
           context->height) {
-    gif_image = nullptr;
-    context->ThrowError("Image Data Out Of LSD, The File May Be Corrupt");
-    NOTREACHED();
+    context->AddError("Image Data Out Of LSD, The File May Be Corrupt");
     return GifDecodeStatus::Error;
   }
   GifLF* gif_img_info_lf_ptr = (GifLF*)&gif_img_info_ptr->local_flag;
@@ -182,8 +179,7 @@ void gif_decoding_failure_at_tail_cleanup(CGifContext* context,
                                           GifImage* gif_image_ptr) {
   gif_image_ptr->m_ImageRowBuf.clear();
   gif_save_decoding_status(context, GIF_D_STATUS_TAIL);
-  context->ThrowError("Decode Image Data Error");
-  NOTREACHED();
+  context->AddError("Decode Image Data Error");
 }
 
 }  // namespace
@@ -378,8 +374,7 @@ GifDecodeStatus gif_read_header(CGifContext* context) {
 
   if (strncmp(gif_header_ptr->signature, GIF_SIGNATURE, 3) != 0 ||
       gif_header_ptr->version[0] != '8' || gif_header_ptr->version[2] != 'a') {
-    context->ThrowError("Not A Gif Image");
-    NOTREACHED();
+    context->AddError("Not A Gif Image");
     return GifDecodeStatus::Error;
   }
   GifLSD* gif_lsd_ptr = nullptr;
@@ -474,6 +469,7 @@ GifDecodeStatus gif_get_frame(CGifContext* context) {
         ret = gif_decode_image_info(context);
         if (ret != GifDecodeStatus::Success)
           return ret;
+
         continue;
       }
       case GIF_D_STATUS_IMG_DATA: {
@@ -517,8 +513,7 @@ GifDecodeStatus gif_load_frame(CGifContext* context, int32_t frame_num) {
   GifImage* gif_image_ptr = context->m_Images[frame_num].get();
   uint32_t gif_img_row_bytes = gif_image_ptr->m_ImageInfo.width;
   if (gif_img_row_bytes == 0) {
-    context->ThrowError("Error Invalid Number of Row Bytes");
-    NOTREACHED();
+    context->AddError("Error Invalid Number of Row Bytes");
     return GifDecodeStatus::Error;
   }
   if (context->decode_status == GIF_D_STATUS_TAIL) {
@@ -541,8 +536,7 @@ GifDecodeStatus gif_load_frame(CGifContext* context, int32_t frame_num) {
           (bool)((GifLF*)&gif_image_ptr->m_ImageInfo.local_flag)->interlace);
       if (!bRes) {
         gif_image_ptr->m_ImageRowBuf.clear();
-        context->ThrowError("Error Read Record Position Data");
-        NOTREACHED();
+        context->AddError("Error Read Record Position Data");
         return GifDecodeStatus::Error;
       }
     } else {
@@ -560,15 +554,13 @@ GifDecodeStatus gif_load_frame(CGifContext* context, int32_t frame_num) {
           (bool)((GifLF*)&gif_image_ptr->m_ImageInfo.local_flag)->interlace);
       if (!bRes) {
         gif_image_ptr->m_ImageRowBuf.clear();
-        context->ThrowError("Error Read Record Position Data");
-        NOTREACHED();
+        context->AddError("Error Read Record Position Data");
         return GifDecodeStatus::Error;
       }
     }
     if (gif_image_ptr->image_code_size >= 13) {
       gif_image_ptr->m_ImageRowBuf.clear();
-      context->ThrowError("Error Invalid Code Size");
-      NOTREACHED();
+      context->AddError("Error Invalid Code Size");
       return GifDecodeStatus::Error;
     }
     if (!context->m_ImgDecoder.get())
@@ -665,8 +657,7 @@ GifDecodeStatus gif_load_frame(CGifContext* context, int32_t frame_num) {
     }
     gif_save_decoding_status(context, GIF_D_STATUS_TAIL);
   }
-  context->ThrowError("Decode Image Data Error");
-  NOTREACHED();
+  context->AddError("Decode Image Data Error");
   return GifDecodeStatus::Error;
 }
 
diff --git a/core/fxcodec/lgif/fx_gif.h b/core/fxcodec/lgif/fx_gif.h
index d7cd5d83fb..5216eeb70e 100644
--- a/core/fxcodec/lgif/fx_gif.h
+++ b/core/fxcodec/lgif/fx_gif.h
@@ -7,7 +7,6 @@
 #ifndef CORE_FXCODEC_LGIF_FX_GIF_H_
 #define CORE_FXCODEC_LGIF_FX_GIF_H_
 
-#include <setjmp.h>
 #include <memory>
 #include <vector>