Disk Cache: Don't depend on the backend being enabled to...

net/disk_cache/entry_impl.cc

 // Copyright (c) 2006-2009 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/disk_cache/entry_impl.h"
 
 #include "base/histogram.h"
 #include "base/message_loop.h"
 #include "base/string_util.h"
 #include "net/base/io_buffer.h"
@@ skipping 66 matching lines @@
 namespace disk_cache {
 
 EntryImpl::EntryImpl(BackendImpl* backend, Addr address)
     : entry_(NULL, Addr(0)), node_(NULL, Addr(0)) {
   entry_.LazyInit(backend->File(address), address);
   doomed_ = false;
   backend_ = backend;
   for (int i = 0; i < kNumStreams; i++) {
     unreported_size_[i] = 0;
   }
+  key_file_ = NULL;
 }
 
 // When an entry is deleted from the cache, we clean up all the data associated
 // with it for two reasons: to simplify the reuse of the block (we know that any
 // unused block is filled with zeros), and to simplify the handling of write /
 // read partial information from an entry (don't have to worry about returning
 // data related to a previous cache entry because the range was not fully
 // written before).
 EntryImpl::~EntryImpl() {
   // Save the sparse info to disk before deleting this entry.
@@ skipping 35 matching lines @@
   SetPointerForInvalidEntry(backend_->GetCurrentEntryId());
   backend_->InternalDoomEntry(this);
 }
 
 void EntryImpl::Close() {
   Release();
 }
 
 std::string EntryImpl::GetKey() const {
   CacheEntryBlock* entry = const_cast<CacheEntryBlock*>(&entry_);
-  if (entry->Data()->key_len > kMaxInternalKeyLength) {
-    Addr address(entry->Data()->long_key);
-    DCHECK(address.is_initialized());
+  if (entry->Data()->key_len <= kMaxInternalKeyLength)
+    return std::string(entry->Data()->key);
+
+  Addr address(entry->Data()->long_key);
+  DCHECK(address.is_initialized());
+  size_t offset = 0;
+  if (address.is_block_file())
+    offset = address.start_block() * address.BlockSize() + kBlockHeaderSize;
+
+  if (!key_file_) {
+    // We keep a copy of the file needed to access the key so that we can
+    // always return this object's key, even if the backend is disabled.
     COMPILE_ASSERT(kNumStreams == kKeyFileIndex, invalid_key_index);
-    File* file = const_cast<EntryImpl*>(this)->GetBackingFile(address,
-                                                              kKeyFileIndex);
+    key_file_ = const_cast<EntryImpl*>(this)->GetBackingFile(address,
+                                                             kKeyFileIndex);
+  }
 
-    size_t offset = 0;
-    if (address.is_block_file())
-      offset = address.start_block() * address.BlockSize() + kBlockHeaderSize;
-
-    std::string key;
-    if (!file || !file->Read(WriteInto(&key, entry->Data()->key_len + 1),
-                             entry->Data()->key_len + 1, offset))
-      key.clear();
-    return key;
-  } else {
-    return std::string(entry->Data()->key);
-  }
+  std::string key;
+  if (!key_file_ ||
+      !key_file_->Read(WriteInto(&key, entry->Data()->key_len + 1),
+                       entry->Data()->key_len + 1, offset))
+    key.clear();
+  return key;
 }
 
 Time EntryImpl::GetLastUsed() const {
   CacheRankingsBlock* node = const_cast<CacheRankingsBlock*>(&node_);
   return Time::FromInternalValue(node->Data()->last_used);
 }
 
 Time EntryImpl::GetLastModified() const {
   CacheRankingsBlock* node = const_cast<CacheRankingsBlock*>(&node_);
   return Time::FromInternalValue(node->Data()->last_modified);
@@ skipping 224 matching lines @@
 
   entry_store->hash = hash;
   entry_store->creation_time = Time::Now().ToInternalValue();
   entry_store->key_len = static_cast<int32>(key.size());
   if (entry_store->key_len > kMaxInternalKeyLength) {
     Addr address(0);
     if (!CreateBlock(entry_store->key_len + 1, &address))
       return false;
 
     entry_store->long_key = address.value();
-    File* file = GetBackingFile(address, kKeyFileIndex);
+    key_file_ = GetBackingFile(address, kKeyFileIndex);
 
     size_t offset = 0;
     if (address.is_block_file())
       offset = address.start_block() * address.BlockSize() + kBlockHeaderSize;
 
-    if (!file || !file->Write(key.data(), key.size(), offset)) {
+    if (!key_file_ || !key_file_->Write(key.data(), key.size(), offset)) {
       DeleteData(address, kKeyFileIndex);
       return false;
     }
 
     if (address.is_separate_file())
-      file->SetLength(key.size() + 1);
+      key_file_->SetLength(key.size() + 1);
   } else {
     memcpy(entry_store->key, key.data(), key.size());
     entry_store->key[key.size()] = '\0';
   }
   backend_->ModifyStorageSize(0, static_cast<int32>(key.size()));
   node->dirty = backend_->GetCurrentEntryId();
   Log("Create Entry ");
   return true;
 }
 
@@ skipping 461 matching lines @@
   Trace("%s 0x%p 0x%x 0x%x", msg, reinterpret_cast<void*>(this),
         entry_.address().value(), node_.address().value());
 
   Trace("  data: 0x%x 0x%x 0x%x", entry_.Data()->data_addr[0],
         entry_.Data()->data_addr[1], entry_.Data()->long_key);
 
   Trace("  doomed: %d 0x%x", doomed_, dirty);
 }
 
 }  // namespace disk_cache