Various changes to JBig2 cache:

core/src/fxcodec/jbig2/JBig2_Context.cpp

 // Copyright 2014 PDFium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
 
 #include "JBig2_Context.h"
 
 #include <list>
 
@@ skipping 16 matching lines @@
 
 }  // namespace
 
 // Implement a very small least recently used (LRU) cache. It is very
 // common for a JBIG2 dictionary to span multiple pages in a PDF file,
 // and we do not want to decode the same dictionary over and over
 // again. We key off of the memory location of the dictionary. The
 // list keeps track of the freshness of entries, with freshest ones
 // at the front. Even a tiny cache size like 2 makes a dramatic
 // difference for typical JBIG2 documents.
-//
-// Disabled until we can figure out how to clear cache between documents.
-// https://code.google.com/p/pdfium/issues/detail?id=207
-#define DISABLE_SYMBOL_CACHE
-#ifndef DISABLE_SYMBOL_CACHE
 static const int kSymbolDictCacheMaxSize = 2;
-#endif
 
 CJBig2_Context* CJBig2_Context::CreateContext(
-    const uint8_t* pGlobalData,
-    FX_DWORD dwGlobalLength,
-    const uint8_t* pData,
-    FX_DWORD dwLength,
+    CPDF_StreamAcc* pGlobalStream,
+    CPDF_StreamAcc* pSrcStream,
     std::list<CJBig2_CachePair>* pSymbolDictCache,
     IFX_Pause* pPause) {
-  return new CJBig2_Context(pGlobalData, dwGlobalLength, pData, dwLength,
-                            pSymbolDictCache, pPause);
+  return new CJBig2_Context(pGlobalStream, pSrcStream, pSymbolDictCache, pPause,
+                            false);
 }
 
 void CJBig2_Context::DestroyContext(CJBig2_Context* pContext) {
   delete pContext;
 }
 
-CJBig2_Context::CJBig2_Context(const uint8_t* pGlobalData,
-                               FX_DWORD dwGlobalLength,
-                               const uint8_t* pData,
-                               FX_DWORD dwLength,
+CJBig2_Context::CJBig2_Context(CPDF_StreamAcc* pGlobalStream,
+                               CPDF_StreamAcc* pSrcStream,
                                std::list<CJBig2_CachePair>* pSymbolDictCache,
-                               IFX_Pause* pPause)
+                               IFX_Pause* pPause,
+                               bool bIsGlobal)
     : m_nSegmentDecoded(0),
       m_bInPage(false),
       m_bBufSpecified(false),
       m_PauseStep(10),
       m_pPause(pPause),
       m_ProcessingStatus(FXCODEC_STATUS_FRAME_READY),
       m_gbContext(NULL),
       m_dwOffset(0),
-      m_pSymbolDictCache(pSymbolDictCache) {
-  if (pGlobalData && (dwGlobalLength > 0)) {
-    m_pGlobalContext = new CJBig2_Context(
-        nullptr, 0, pGlobalData, dwGlobalLength, pSymbolDictCache, pPause);
+      m_pSymbolDictCache(pSymbolDictCache),
+      m_bIsGlobal(bIsGlobal) {
+  if (pGlobalStream && (pGlobalStream->GetSize() > 0)) {
+    m_pGlobalContext =
+        new CJBig2_Context(NULL, pGlobalStream, pSymbolDictCache, pPause, true);

[Lei Zhang, 2015/10/08 03:22:44]

nit: nullptr

[David Lattimore, 2015/10/08 03:44:39]

Done.

   } else {
     m_pGlobalContext = nullptr;
   }
 
-  m_pStream.reset(new CJBig2_BitStream(pData, dwLength));
+  m_pStream.reset(new CJBig2_BitStream(pSrcStream));
 }
 
 CJBig2_Context::~CJBig2_Context() {
   FX_Free(m_gbContext);
   m_gbContext = NULL;
   delete m_pGlobalContext;
   m_pGlobalContext = NULL;
 }
 
 int32_t CJBig2_Context::decode_SquentialOrgnazation(IFX_Pause* pPause) {
@@ skipping 230 matching lines @@
       return JBIG2_ERROR_TOO_SHORT;
     pSegment->m_dwPage_association = cTemp;
   } else {
     if (m_pStream->readInteger(&pSegment->m_dwPage_association) != 0) {
       return JBIG2_ERROR_TOO_SHORT;
     }
   }
   if (m_pStream->readInteger(&pSegment->m_dwData_length) != 0)
     return JBIG2_ERROR_TOO_SHORT;
 
-  pSegment->m_pData = m_pStream->getPointer();
+  pSegment->m_dwObjNum = m_pStream->getObjNum();
+  pSegment->m_dwDataOffset = m_pStream->getOffset();
   pSegment->m_State = JBIG2_SEGMENT_DATA_UNPARSED;
   return JBIG2_SUCCESS;
 }
 
 int32_t CJBig2_Context::parseSegmentData(CJBig2_Segment* pSegment,
                                          IFX_Pause* pPause) {
   int32_t ret = ProcessingParseSegmentData(pSegment, pPause);
   while (m_ProcessingStatus == FXCODEC_STATUS_DECODE_TOBECONTINUE &&
          m_pStream->getByteLeft() > 0) {
     ret = ProcessingParseSegmentData(pSegment, pPause);
@@ skipping 249 matching lines @@
       const size_t size = GetHuffContextSize(pSymbolDictDecoder->SDTEMPLATE);
       gbContext.reset(FX_Alloc(JBig2ArithCtx, size));
       JBIG2_memset(gbContext.get(), 0, sizeof(JBig2ArithCtx) * size);
     }
     if (pSymbolDictDecoder->SDREFAGG == 1) {
       const size_t size = GetRefAggContextSize(pSymbolDictDecoder->SDRTEMPLATE);
       grContext.reset(FX_Alloc(JBig2ArithCtx, size));
       JBIG2_memset(grContext.get(), 0, sizeof(JBig2ArithCtx) * size);
     }
   }
-  const uint8_t* key = pSegment->m_pData;
+  CJBig2_CacheKey key =
+      CJBig2_CacheKey(pSegment->m_dwObjNum, pSegment->m_dwDataOffset);
   FX_BOOL cache_hit = false;
   pSegment->m_nResultType = JBIG2_SYMBOL_DICT_POINTER;
-  for (std::list<CJBig2_CachePair>::iterator it = m_pSymbolDictCache->begin();
-       it != m_pSymbolDictCache->end(); ++it) {
-    if (it->first == key) {
-      nonstd::unique_ptr<CJBig2_SymbolDict> copy(it->second->DeepCopy());
-      pSegment->m_Result.sd = copy.release();
-      m_pSymbolDictCache->push_front(*it);
-      m_pSymbolDictCache->erase(it);
-      cache_hit = true;
-      break;
+  if (m_bIsGlobal) {
+    for (auto it = m_pSymbolDictCache->begin(); it != m_pSymbolDictCache->end();
+         ++it) {
+      if (it->first == key) {
+        nonstd::unique_ptr<CJBig2_SymbolDict> copy(it->second->DeepCopy());
+        pSegment->m_Result.sd = copy.release();
+        m_pSymbolDictCache->push_front(*it);
+        m_pSymbolDictCache->erase(it);
+        cache_hit = true;
+        break;
+      }
     }
   }
   if (!cache_hit) {
     if (pSymbolDictDecoder->SDHUFF == 0) {
       nonstd::unique_ptr<CJBig2_ArithDecoder> pArithDecoder(
           new CJBig2_ArithDecoder(m_pStream.get()));
       pSegment->m_Result.sd = pSymbolDictDecoder->decode_Arith(
           pArithDecoder.get(), gbContext.get(), grContext.get());
       if (!pSegment->m_Result.sd)
         return JBIG2_ERROR_FATAL;
 
       m_pStream->alignByte();
       m_pStream->offset(2);
     } else {
       pSegment->m_Result.sd = pSymbolDictDecoder->decode_Huffman(
           m_pStream.get(), gbContext.get(), grContext.get(), pPause);
       if (!pSegment->m_Result.sd)
         return JBIG2_ERROR_FATAL;
       m_pStream->alignByte();
     }
-#ifndef DISABLE_SYMBOL_CACHE
-    nonstd::unique_ptr<CJBig2_SymbolDict> value =
-        pSegment->m_Result.sd->DeepCopy();
-    if (value && kSymbolDictCacheMaxSize > 0) {
-      while (m_pSymbolDictCache->size() >= kSymbolDictCacheMaxSize) {
-        delete m_pSymbolDictCache->back().second;
-        m_pSymbolDictCache->pop_back();
+    if (m_bIsGlobal && kSymbolDictCacheMaxSize > 0) {
+      nonstd::unique_ptr<CJBig2_SymbolDict> value =
+          pSegment->m_Result.sd->DeepCopy();
+      if (value) {
+        while (m_pSymbolDictCache->size() >= kSymbolDictCacheMaxSize) {
+          delete m_pSymbolDictCache->back().second;
+          m_pSymbolDictCache->pop_back();
+        }
+        m_pSymbolDictCache->push_front(CJBig2_CachePair(key, value.release()));
       }
-      m_pSymbolDictCache->push_front(CJBig2_CachePair(key, value.release()));
     }
-#endif
   }
   if (wFlags & 0x0200) {
     pSegment->m_Result.sd->m_bContextRetained = TRUE;
     if (pSymbolDictDecoder->SDHUFF == 0) {
       pSegment->m_Result.sd->m_gbContext = gbContext.release();
     }
     if (pSymbolDictDecoder->SDREFAGG == 1) {
       pSegment->m_Result.sd->m_grContext = grContext.release();
     }
   }
@@ skipping 771 matching lines @@
         SBSYMCODES[CURTEMP].code = CURCODE;
         CURCODE = CURCODE + 1;
       }
       CURTEMP = CURTEMP + 1;
     }
     CURLEN = CURLEN + 1;
   }
   FX_Free(LENCOUNT);
   FX_Free(FIRSTCODE);
 }