Add support to extension_shell and ash_shell to use external V8 snapshot files.

gin/isolate_holder.cc

 // 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.
 
 #include "gin/public/isolate_holder.h"
 
 #include <stdlib.h>
 #include <string.h>
 
+#include "base/files/file.h"
 #include "base/files/memory_mapped_file.h"
 #include "base/logging.h"
 #include "base/message_loop/message_loop.h"
 #include "base/rand_util.h"
 #include "base/strings/sys_string_conversions.h"
 #include "base/sys_info.h"
 #include "crypto/sha2.h"
 #include "gin/array_buffer.h"
 #include "gin/debug_impl.h"
 #include "gin/function_template.h"
@@ skipping 16 matching lines @@
 
 bool GenerateEntropy(unsigned char* buffer, size_t amount) {
   base::RandBytes(buffer, amount);
   return true;
 }
 
 base::MemoryMappedFile* g_mapped_natives = NULL;
 base::MemoryMappedFile* g_mapped_snapshot = NULL;
 
 #if defined(V8_USE_EXTERNAL_STARTUP_DATA)
+#if !defined(OS_MACOSX)
+const int kV8SnapshotBasePathKey =
+#if defined(OS_ANDROID)
+    base::DIR_ANDROID_APP_DATA;
+#elif defined(OS_POSIX)
+    base::DIR_EXE;
+#elif defined(OS_WIN)
+    base::DIR_MODULE;
+#endif  // OS_ANDROID
+#endif  // !OS_MACOSX
+
+const char kNativesFileName[] = "natives_blob.bin";
+const char kSnapshotFileName[] = "snapshot_blob.bin";
+
+void GetV8FilePaths(base::FilePath* natives_path_out,
+                    base::FilePath* snapshot_path_out) {
+#if !defined(OS_MACOSX)
+  base::FilePath data_path;
+  PathService::Get(kV8SnapshotBasePathKey, &data_path);
+  DCHECK(!data_path.empty());
+
+  *natives_path_out = data_path.AppendASCII(kNativesFileName);
+  *snapshot_path_out = data_path.AppendASCII(kSnapshotFileName);
+#else   // !defined(OS_MACOSX)
+  base::ScopedCFTypeRef<CFStringRef> natives_file_name(
+      base::SysUTF8ToCFStringRef(kNativesFileName));
+  *natives_path_out =
+      base::mac::PathForFrameworkBundleResource(natives_file_name);
+  base::ScopedCFTypeRef<CFStringRef> snapshot_file_name(
+      base::SysUTF8ToCFStringRef(kSnapshotFileName));
+  *snapshot_path_out =
+      base::mac::PathForFrameworkBundleResource(snapshot_file_name);
+  DCHECK(!natives_path.empty());
+  DCHECK(!snapshot_path.empty());
+#endif  // !defined(OS_MACOSX)
+}
+
 bool MapV8Files(base::FilePath* natives_path,
                 base::FilePath* snapshot_path,
                 int natives_fd = -1,
                 int snapshot_fd = -1,
                 base::MemoryMappedFile::Region natives_region =
                     base::MemoryMappedFile::Region::kWholeFile,
                 base::MemoryMappedFile::Region snapshot_region =
                     base::MemoryMappedFile::Region::kWholeFile) {
   int flags = base::File::FLAG_OPEN | base::File::FLAG_READ;
 
@@ skipping 54 matching lines @@
 }  // namespace
 
 #if defined(V8_USE_EXTERNAL_STARTUP_DATA)
 
 #if defined(V8_VERIFY_EXTERNAL_STARTUP_DATA)
 // Defined in gen/gin/v8_snapshot_fingerprint.cc
 extern const unsigned char g_natives_fingerprint[];
 extern const unsigned char g_snapshot_fingerprint[];
 #endif  // V8_VERIFY_EXTERNAL_STARTUP_DATA
 
-#if !defined(OS_MACOSX)
-const int IsolateHolder::kV8SnapshotBasePathKey =
-#if defined(OS_ANDROID)
-    base::DIR_ANDROID_APP_DATA;
-#elif defined(OS_POSIX)
-    base::DIR_EXE;
-#elif defined(OS_WIN)
-    base::DIR_MODULE;
-#endif  // OS_ANDROID
-#endif  // !OS_MACOSX
-
-const char IsolateHolder::kNativesFileName[] = "natives_blob.bin";
-const char IsolateHolder::kSnapshotFileName[] = "snapshot_blob.bin";
-
 // static
 bool IsolateHolder::LoadV8Snapshot() {
   if (g_mapped_natives && g_mapped_snapshot)
     return true;
 
-#if !defined(OS_MACOSX)
-  base::FilePath data_path;
-  PathService::Get(kV8SnapshotBasePathKey, &data_path);
-  DCHECK(!data_path.empty());
-
-  base::FilePath natives_path = data_path.AppendASCII(kNativesFileName);
-  base::FilePath snapshot_path = data_path.AppendASCII(kSnapshotFileName);
-#else  // !defined(OS_MACOSX)
-  base::ScopedCFTypeRef<CFStringRef> natives_file_name(
-      base::SysUTF8ToCFStringRef(kNativesFileName));
-  base::FilePath natives_path = base::mac::PathForFrameworkBundleResource(
-      natives_file_name);
-  base::ScopedCFTypeRef<CFStringRef> snapshot_file_name(
-      base::SysUTF8ToCFStringRef(kSnapshotFileName));
-  base::FilePath snapshot_path = base::mac::PathForFrameworkBundleResource(
-      snapshot_file_name);
-  DCHECK(!natives_path.empty());
-  DCHECK(!snapshot_path.empty());
-#endif  // !defined(OS_MACOSX)
-
+  base::FilePath natives_path;
+  base::FilePath snapshot_path;
+  GetV8FilePaths(&natives_path, &snapshot_path);
   if (!MapV8Files(&natives_path, &snapshot_path))
     return false;
 
 #if defined(V8_VERIFY_EXTERNAL_STARTUP_DATA)
   return VerifyV8SnapshotFile(g_mapped_natives, g_natives_fingerprint) &&
          VerifyV8SnapshotFile(g_mapped_snapshot, g_snapshot_fingerprint);
 #else
   return true;
 #endif  // V8_VERIFY_EXTERNAL_STARTUP_DATA
 }
@@ skipping 18 matching lines @@
   base::MemoryMappedFile::Region snapshot_region =
       base::MemoryMappedFile::Region::kWholeFile;
   if (natives_size != 0 || natives_offset != 0) {
     snapshot_region =
         base::MemoryMappedFile::Region(snapshot_offset, snapshot_size);
   }
 
   return MapV8Files(
       NULL, NULL, natives_fd, snapshot_fd, natives_region, snapshot_region);
 }
+
+// static
+bool IsolateHolder::OpenV8FilesForChildProcesses(
+    base::PlatformFile* natives_fd_out,
+    base::PlatformFile* snapshot_fd_out) {
+  base::FilePath natives_data_path;
+  base::FilePath snapshot_data_path;
+  GetV8FilePaths(&natives_data_path, &snapshot_data_path);
+
+  int file_flags = base::File::FLAG_OPEN | base::File::FLAG_READ;
+  base::File natives_data_file(natives_data_path, file_flags);
+  base::File snapshot_data_file(snapshot_data_path, file_flags);
+
+  if (!natives_data_file.IsValid() || !snapshot_data_file.IsValid())
+    return false;
+
+  *natives_fd_out = natives_data_file.TakePlatformFile();
+  *snapshot_fd_out = snapshot_data_file.TakePlatformFile();
+  return true;
+}
 #endif  // V8_USE_EXTERNAL_STARTUP_DATA
 
 //static
 void IsolateHolder::GetV8ExternalSnapshotData(const char** natives_data_out,
                                               int* natives_size_out,
                                               const char** snapshot_data_out,
                                               int* snapshot_size_out) {
   if (!g_mapped_natives || !g_mapped_snapshot) {
     *natives_data_out = *snapshot_data_out = NULL;
     *natives_size_out = *snapshot_size_out = 0;
@@ skipping 84 matching lines @@
   base::MessageLoop::current()->AddTaskObserver(task_observer_.get());
 }
 
 void IsolateHolder::RemoveRunMicrotasksObserver() {
   DCHECK(task_observer_.get());
   base::MessageLoop::current()->RemoveTaskObserver(task_observer_.get());
   task_observer_.reset();
 }
 
 }  // namespace gin