Modularize Compact Language Detector 2 (CLD2) data sources

components/translate/content/renderer/data_file_renderer_cld_data_provider.h

+// Copyright 2014 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 COMPONENTS_TRANSLATE_CONTENT_RENDERER_DATA_FILE_RENDERER_CLD_DATA_PROVIDER_H_
+#define COMPONENTS_TRANSLATE_CONTENT_RENDERER_DATA_FILE_RENDERER_CLD_DATA_PROVIDER_H_
+
+#include "base/files/file.h"
+#include "base/files/memory_mapped_file.h"
+#include "base/lazy_instance.h"
+#include "base/macros.h"
+#include "base/memory/weak_ptr.h"
+#include "components/translate/content/renderer/renderer_cld_data_provider.h"
+#include "ipc/ipc_platform_file.h"
+
+namespace translate {
+
+class DataFileRendererCldDataProvider : public RendererCldDataProvider {
+ public:
+  explicit DataFileRendererCldDataProvider(content::RenderViewObserver*);
+  virtual ~DataFileRendererCldDataProvider();
+  // RendererCldDataProvider implementations:
+  virtual bool OnMessageReceived(const IPC::Message&) OVERRIDE;
+  virtual void SendCldDataRequest() OVERRIDE;
+  virtual void SetCldAvailableCallback(base::Callback<void(void)>) OVERRIDE;
+  virtual bool IsCldDataAvailable() OVERRIDE;
+
+ private:
+  void OnCldDataAvailable(const IPC::PlatformFileForTransit ipc_file_handle,
+                          const uint64 data_offset,
+                          const uint64 data_length);
+  void LoadCldData(base::File file,
+                    const uint64 data_offset,

[Takashi Toyoshima, 2014/06/23 09:22:58]

indent nits on line 33 and 34.

[Andrew Hayden (chromium.org), 2014/06/23 13:54:43]

Done.

+                    const uint64 data_length);
+  content::RenderViewObserver* render_view_observer;

[Takashi Toyoshima, 2014/06/23 09:22:58]

render_view_observer_

[Andrew Hayden (chromium.org), 2014/06/23 13:54:43]

Done.

+  base::Callback<void(void)> cld_available_callback;

[Takashi Toyoshima, 2014/06/23 09:22:58]

cld_available_callback_

[Andrew Hayden (chromium.org), 2014/06/23 13:54:43]

Done.

+  // A struct that contains the pointer to the CLD mmap. Used so that we can

[Takashi Toyoshima, 2014/06/23 09:22:58]

Following definitions can be moved to .cc file in anonymous namespace.
Also, do you really need to define struct CLDMmapWrapper? It looks just a
base::MemoryMappedFile*.

[Andrew Hayden (chromium.org), 2014/06/23 13:54:43]

LazyInstance::Leaky is necessary to avoid having the code get detected as a
memory leak. The pattern with the holder class is what I *think* the standard
use case is, and is what we have been using up till now anyways. Is there a
different pattern you'd like to see here?

[Takashi Toyoshima, 2014/06/24 02:09:47]

Ah, I see. Thank you for your explanation!

+  // leverage LazyInstance:Leaky to properly scope the lifetime of the mmap.
+  struct CLDMmapWrapper {
+    CLDMmapWrapper() {
+      value = NULL;
+    }
+    base::MemoryMappedFile* value;
+  };
+  static base::LazyInstance<CLDMmapWrapper>::Leaky s_cld_mmap_;
+
+  DISALLOW_COPY_AND_ASSIGN(DataFileRendererCldDataProvider);
+};
+
+}  // namespace translate
+
+#endif  // COMPONENTS_TRANSLATE_CONTENT_RENDERER_DATA_FILE_RENDERER_CLD_DATA_PROVIDER_H_