Load v8 snapshots directly from APK (and store them uncompressed)

gin/v8_initializer.h

 // Copyright 2013 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 GIN_V8_INITIALIZER_H_
 #define GIN_V8_INITIALIZER_H_
 
 #include "base/files/file.h"
+#include "base/files/memory_mapped_file.h"
 #include "gin/array_buffer.h"
 #include "gin/gin_export.h"
 #include "gin/public/isolate_holder.h"
 #include "gin/public/v8_platform.h"
 #include "v8/include/v8.h"
 
 namespace gin {
 
 class GIN_EXPORT V8Initializer {
  public:
-  static const int kV8SnapshotBasePathKey;
-  static const char kNativesFileName[];
-  static const char kSnapshotFileName[];
-
   // This should be called by IsolateHolder::Initialize().
   static void Initialize(gin::IsolateHolder::ScriptMode mode);
 
   // Get address and size information for currently loaded snapshot.
   // If no snapshot is loaded, the return values are null for addresses
   // and 0 for sizes.
   static void GetV8ExternalSnapshotData(const char** natives_data_out,
                                         int* natives_size_out,
                                         const char** snapshot_data_out,
                                         int* snapshot_size_out);
 
-#if defined(V8_USE_EXTERNAL_STARTUP_DATA)
+#if defined(OS_POSIX) && defined(V8_USE_EXTERNAL_STARTUP_DATA)
+
+  struct V8Files {
+    base::ScopedFD natives_fd;
+    base::ScopedFD snapshot_fd;
+    base::MemoryMappedFile::Region natives_region;
+    base::MemoryMappedFile::Region snapshot_region;
+   public:
+    bool IsLoaded() const;
+  };
 
   // Load V8 snapshot from user provided platform file descriptors.
   // The offset and size arguments, if non-zero, specify the portions
   // of the files to be loaded. This methods returns true on success
   // (or if snapshot is already loaded), false otherwise.
   static bool LoadV8SnapshotFromFD(base::PlatformFile natives_fd,
                                    int64 natives_offset,
                                    int64 natives_size,
                                    base::PlatformFile snapshot_fd,
                                    int64 snapshot_offset,
                                    int64 snapshot_size);
 
   // Load V8 snapshot from default resources. Returns true on success or
   // snapshot is already loaded, false otherwise.
   static bool LoadV8Snapshot();
 
-  // Opens the V8 snapshot data files and returns open file descriptors to these
-  // files in |natives_fd_out| and |snapshot_fd_out|, which can be passed to
-  // child processes.
-  static bool OpenV8FilesForChildProcesses(base::PlatformFile* natives_fd_out,
-                                           base::PlatformFile* snapshot_fd_out);
+  // Opens the V8 snapshot data files and returns open file descriptors and
+  // file regions to these files that can be passed to child processes.
+  static void OpenV8FilesForChildProcesses(V8Files* files_out);
 
 #endif  // V8_USE_EXTERNAL_STARTUP_DATA
 };
 
 }  // namespace gin
 
 #endif  // GIN_V8_INITIALIZER_H_