Make CPDF_ImageCacheEntry retain CPDF_Image

CPDF_PageRenderCache::m_ImageCache is a map from streams to
an image cache entry containing a clump of data associated
with the stream. Oddly, the clump includes the stream key (which
we already have in order to get to the clump), but worse doesn't
ensure the existence of the CPDF_Image object which (maybe) owns
the stream key in question.

So replace the stream with a retained ptr to the image.

Also renamed an unrelated member to avoid confusion with the
CPDF_Object in play.

Bug: 724460
Change-Id: Id13d2c246918d4ff78c12b5bdb927f99c3f5e4e1
Reviewed-on: https://pdfium-review.googlesource.com/5771
Commit-Queue: Tom Sepez <tsepez@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>

1 files changed, 15 insertions, 8 deletions

diff --git a/core/fpdfapi/render/cpdf_pagerendercache.cpp b/core/fpdfapi/render/cpdf_pagerendercache.cpp
index cc1f267f14..a997e34906 100644
--- a/core/fpdfapi/render/cpdf_pagerendercache.cpp
+++ b/core/fpdfapi/render/cpdf_pagerendercache.cpp
@@ -9,6 +9,7 @@
 #include <algorithm>
 #include <vector>
 
+#include "core/fpdfapi/page/cpdf_image.h"
 #include "core/fpdfapi/page/cpdf_page.h"
 #include "core/fpdfapi/render/cpdf_imagecacheentry.h"
 #include "core/fpdfapi/render/cpdf_renderstatus.h"
@@ -45,8 +46,10 @@ void CPDF_PageRenderCache::CacheOptimization(int32_t dwLimitCacheSize) {
   size_t nCount = m_ImageCache.size();
   std::vector<CacheInfo> cache_info;
   cache_info.reserve(nCount);
-  for (const auto& it : m_ImageCache)
-    cache_info.emplace_back(it.second->GetTimeCount(), it.second->GetStream());
+  for (const auto& it : m_ImageCache) {
+    cache_info.emplace_back(it.second->GetTimeCount(),
+                            it.second->GetImage()->GetStream());
+  }
   std::sort(cache_info.begin(), cache_info.end());
 
   // Check if time value is about to roll over and reset all entries.
@@ -77,18 +80,19 @@ void CPDF_PageRenderCache::ClearImageCacheEntry(CPDF_Stream* pStream) {
 }
 
 bool CPDF_PageRenderCache::StartGetCachedBitmap(
-    CPDF_Stream* pStream,
+    const CFX_RetainPtr<CPDF_Image>& pImage,
     bool bStdCS,
     uint32_t GroupFamily,
     bool bLoadMask,
     CPDF_RenderStatus* pRenderStatus) {
+  CPDF_Stream* pStream = pImage->GetStream();
   const auto it = m_ImageCache.find(pStream);
   m_bCurFindCache = it != m_ImageCache.end();
   if (m_bCurFindCache) {
     m_pCurImageCacheEntry = it->second;
   } else {
     m_pCurImageCacheEntry =
-        new CPDF_ImageCacheEntry(m_pPage->m_pDocument.Get(), pStream);
+        new CPDF_ImageCacheEntry(m_pPage->m_pDocument.Get(), pImage);
   }
   int ret = m_pCurImageCacheEntry->StartGetCachedBitmap(
       pRenderStatus->m_pFormResource, m_pPage->m_pPageResources.Get(), bStdCS,
@@ -113,23 +117,26 @@ bool CPDF_PageRenderCache::Continue(IFX_Pause* pPause,
     return true;
 
   m_nTimeCount++;
-  if (!m_bCurFindCache)
-    m_ImageCache[m_pCurImageCacheEntry->GetStream()] = m_pCurImageCacheEntry;
+  if (!m_bCurFindCache) {
+    m_ImageCache[m_pCurImageCacheEntry->GetImage()->GetStream()] =
+        m_pCurImageCacheEntry;
+  }
   if (!ret)
     m_nCacheSize += m_pCurImageCacheEntry->EstimateSize();
   return false;
 }
 
 void CPDF_PageRenderCache::ResetBitmap(
-    CPDF_Stream* pStream,
+    const CFX_RetainPtr<CPDF_Image>& pImage,
     const CFX_RetainPtr<CFX_DIBitmap>& pBitmap) {
   CPDF_ImageCacheEntry* pEntry;
+  CPDF_Stream* pStream = pImage->GetStream();
   const auto it = m_ImageCache.find(pStream);
   if (it == m_ImageCache.end()) {
     if (!pBitmap)
       return;
 
-    pEntry = new CPDF_ImageCacheEntry(m_pPage->m_pDocument.Get(), pStream);
+    pEntry = new CPDF_ImageCacheEntry(m_pPage->m_pDocument.Get(), pImage);
     m_ImageCache[pStream] = pEntry;
   } else {
     pEntry = it->second;