[BlobAsync] Patch 3: Renderer Classes & Logic

content/child/blob_storage/blob_transport_temporary_holder.h

+// Copyright 2015 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.
+
+#ifndef CONTENT_CHILD_BLOB_STORAGE_BLOB_TRANSPORT_TEMPORARY_HOLDER_H_
+#define CONTENT_CHILD_BLOB_STORAGE_BLOB_TRANSPORT_TEMPORARY_HOLDER_H_
+
+#include <map>
+#include <string>
+#include <vector>
+
+#include "base/memory/scoped_ptr.h"
+#include "base/memory/shared_memory.h"
+#include "content/common/content_export.h"
+#include "ipc/ipc_platform_file.h"
+#include "storage/common/data_element.h"
+
+template <typename T>
+struct DefaultSingletonTraits;
+
+namespace base {
+class SingleThreadTaskRunner;
+}
+
+namespace storage {
+struct BlobItemBytesRequest;
+struct BlobItemBytesResponse;
+}
+
+namespace content {
+
+class BlobConsolidation;
+
+// This class holds all of the blob data that is in the process of being
+// transported to the Browser process. It
+//  * Creates the blob item descriptions for the browser.
+//  * Includes shortcut data in the descriptions.
+//  * Generates responses to blob memory requests.
+class CONTENT_EXPORT BlobTransportTemporaryHolder {
+ public:
+  enum class ResponsesStatus {
+    UNKNOWN,
+    BLOB_NOT_FOUND,
+    INVALID_ITEM_INDEX,
+    INVALID_DATA_RANGE,
+    INVALID_ITEM,
+    INVALID_HANDLE_INDEX,
+    SHARED_MEMORY_MAP_FAILED,
+    SUCCESS
+  };
+
+  BlobTransportTemporaryHolder();
+  virtual ~BlobTransportTemporaryHolder();
+
+  // Gives the blob data to this class to hold.
+  // Returns false if there already exists a blob with that uuid.

[michaeln, 2015/10/21 02:22:24]

The return value probably isn't needed, none of the call sites test it nor
should they since there's no usecase for attempting to create a blob with the
same id.

[dmurph, 2015/10/21 21:47:57]

Ok.  I'm going to keep it for Hold, so we can DCHECK/exit early.

[michaeln, 2015/10/22 21:10:22]

Our style guide says "you should not handle DCHECK() failures", so DCHECK
followed by an early exit shouldn't be used.

https://codereview.chromium.org/1292523002/diff/100001/content/child/blob_sto...

+  bool HoldBlobConsolidation(const std::string& uuid,
+                             scoped_ptr<BlobConsolidation> consolidation);
+
+  // Returns false if the blob doesn't exist.
+  bool GetDescriptions(const std::string& uuid,
+                       size_t max_data_population,
+                       std::vector<storage::DataElement>* out);
+
+  ResponsesStatus GetResponses(
+      const std::string& uuid,
+      const std::vector<storage::BlobItemBytesRequest>& requests,
+      std::vector<base::SharedMemoryHandle>* memory_handles,
+      const std::vector<IPC::PlatformFileForTransit>& file_handles,
+      std::vector<storage::BlobItemBytesResponse>* output);
+
+  void ReleaseBlob(const std::string& uuid);
+
+ private:
+  BlobConsolidation* GetConsolidation(const std::string& uuid);
+
+  std::map<std::string, BlobConsolidation*> blob_storage_;
+
+  DISALLOW_COPY_AND_ASSIGN(BlobTransportTemporaryHolder);
+};
+
+}  // namespace content
+#endif  // CONTENT_CHILD_BLOB_STORAGE_BLOB_TRANSPORT_TEMPORARY_HOLDER_H_