| // Copyright 2017 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 "base/at_exit.h" |
| #include "base/command_line.h" |
| #include "base/files/file_util.h" |
| #include "base/message_loop/message_loop.h" |
| #include "base/single_thread_task_runner.h" |
| #include "base/task/thread_pool/thread_pool.h" |
| #include "base/threading/thread_task_runner_handle.h" |
| #include "gin/v8_initializer.h" |
| #include "mojo/core/embedder/embedder.h" |
| #include "services/service_manager/public/cpp/binder_registry.h" |
| #include "third_party/blink/public/web/blink.h" |
| #include "third_party/blink/public/web/web_v8_context_snapshot.h" |
| #include "v8/include/v8.h" |
| |
| namespace { |
| |
| constexpr char kPredictableFlag[] = "--predictable"; |
| |
| class SnapshotPlatform final : public blink::Platform { |
| public: |
| bool IsTakingV8ContextSnapshot() override { return true; } |
| }; |
| |
| } // namespace |
| |
| // This program takes a snapshot of V8 contexts and writes it out as a file. |
| // The snapshot file is consumed by Blink. |
| // |
| // Usage: |
| // % v8_context_snapshot_generator --output_file=<filename> |
| int main(int argc, char** argv) { |
| base::AtExitManager at_exit; |
| base::CommandLine::Init(argc, argv); |
| #ifdef V8_USE_EXTERNAL_STARTUP_DATA |
| gin::V8Initializer::LoadV8Snapshot(); |
| gin::V8Initializer::LoadV8Natives(); |
| #endif |
| |
| // Set up environment to make Blink and V8 workable. |
| base::MessageLoop message_loop; |
| base::ThreadPool::CreateAndStartWithDefaultParams("TakeSnapshot"); |
| mojo::core::Init(); |
| |
| // Set predictable flag in V8 to generate identical snapshot file. |
| v8::V8::SetFlagsFromString(kPredictableFlag, sizeof(kPredictableFlag) - 1); |
| |
| // Take a snapshot. |
| SnapshotPlatform platform; |
| service_manager::BinderRegistry empty_registry; |
| blink::CreateMainThreadAndInitialize(&platform, &empty_registry); |
| v8::StartupData blob = blink::WebV8ContextSnapshot::TakeSnapshot(); |
| |
| // Save the snapshot as a file. Filename is given in a command line option. |
| base::FilePath file_path = |
| base::CommandLine::ForCurrentProcess()->GetSwitchValuePath("output_file"); |
| CHECK(!file_path.empty()); |
| int written = base::WriteFile(file_path, blob.data, blob.raw_size); |
| int error_code = 0; |
| if (written != blob.raw_size) { |
| fprintf(stderr, "Error: WriteFile of %d snapshot bytes returned %d.\n", |
| blob.raw_size, written); |
| error_code = 1; |
| } |
| |
| delete[] blob.data; |
| |
| // v8::SnapshotCreator used in WebV8ContextSnapshot makes it complex how to |
| // manage lifetime of v8::Isolate, gin::IsolateHolder, and |
| // blink::V8PerIsolateData. Now we complete all works at this point, and can |
| // exit without releasing all those instances correctly. |
| _exit(error_code); |
| } |