URLRequestContext and disk cache for media files

net/disk_cache/entry_impl.cc

Index: net/disk_cache/entry_impl.cc
diff --git a/net/disk_cache/entry_impl.cc b/net/disk_cache/entry_impl.cc
index b64073ae6589cbefe3af886f21afa55b13fcd66d..9db5647b2962e389d335bd0fb4b14f29cba7f504 100644
--- a/net/disk_cache/entry_impl.cc
+++ b/net/disk_cache/entry_impl.cc
@@ -78,8 +78,10 @@ EntryImpl::EntryImpl(BackendImpl* backend, Addr address)
   entry_.LazyInit(backend->File(address), address);
   doomed_ = false;
   backend_ = backend;
-  for (int i = 0; i < NUM_STREAMS; i++)
+  for (int i = 0; i < NUM_STREAMS; i++) {
     unreported_size_[i] = 0;
+    need_file_[i] = false;
+  }
 }
 
 // When an entry is deleted from the cache, we clean up all the data associated
@@ -318,7 +320,9 @@ int EntryImpl::WriteData(int index, int offset, net::IOBuffer* buf, int buf_len,
 
   backend_->OnEvent(Stats::WRITE_DATA);
 
-  if (user_buffers_[index].get()) {
+  // If we have prepared the cache as an external file, we should never use
+  // user_buffers_ and always write to file directly.
+  if (!need_file_[index] && user_buffers_[index].get()) {
     // Complete the operation locally.
     if (!buf_len)
       return 0;
@@ -365,6 +369,43 @@ int EntryImpl::WriteData(int index, int offset, net::IOBuffer* buf, int buf_len,
   return (completed || !completion_callback) ? buf_len : net::ERR_IO_PENDING;
 }
 
+base::PlatformFile EntryImpl::UseExternalFile(int index) {
+  DCHECK(index >= 0 && index < NUM_STREAMS);
+
+  Addr address(entry_.Data()->data_addr[index]);
+
+  // We will not prepare the cache file since the entry is already initialized,
+  // just return the platform file backing the cache.
+  if (address.is_initialized())
+    return GetPlatformFile(index);
+
+  if (!backend_->CreateExternalFile(&address))
+    return base::kInvalidPlatformFileValue;
+
+  entry_.Data()->data_addr[index] = address.value();
+  entry_.Store();
+
+  // Set the flag for this stream so we never use user_buffer_.
+  // TODO(hclam): do we need to save this information to EntryStore?
+  need_file_[index] = true;
+
+  return GetPlatformFile(index);
+}
+
+base::PlatformFile EntryImpl::GetPlatformFile(int index) {
+  DCHECK(index >= 0 && index < NUM_STREAMS);
+
+  Addr address(entry_.Data()->data_addr[index]);
+  if (!address.is_initialized() || !address.is_separate_file())
+    return base::kInvalidPlatformFileValue;
+
+  File* cache_file = GetExternalFile(address, index);
+  if (!cache_file)
+    return base::kInvalidPlatformFileValue;
+
+  return cache_file->platform_file();
+}
+
 uint32 EntryImpl::GetHash() {
   return entry_.Data()->hash;
 }
@@ -603,6 +644,16 @@ File* EntryImpl::GetExternalFile(Addr address, int index) {
 bool EntryImpl::PrepareTarget(int index, int offset, int buf_len,
                               bool truncate) {
   Addr address(entry_.Data()->data_addr[index]);
+
+  // If we are instructed to use an external file, we should never buffer when
+  // writing. We are done with preparation of the target automatically, since
+  // we have already created the external file for writing.
+  if (need_file_[index]) {
+    // Make sure the stream is initialized and is kept in an external file.
+    DCHECK(address.is_initialized() && address.is_separate_file());
+    return true;
+  }
+
   if (address.is_initialized() || user_buffers_[index].get())
     return GrowUserBuffer(index, offset, buf_len, truncate);