Add script streaming API

src/background-parser-thread.cc

+// Copyright 2014 the V8 project 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 "src/background-parser-thread.h"
+
+#include "src/parser.h"
+
+namespace v8 {
+namespace internal {
+
+static const int kBackgroundParserThreadStackSize = 64 * KB;
+
+// To be called on the main thread.
+class FinalizeParsingTask : public v8::Task {
+ public:
+  FinalizeParsingTask(ScriptCompiler::StreamedSource* source, Isolate* isolate,
+                      ScriptCompiler::StreamingCompleteCallback callback,
+                      void* callback_data)
+      : source_(source),
+        isolate_(isolate),
+        callback_(callback),
+        callback_data_(callback_data) {}
+
+  virtual void Run() V8_OVERRIDE {
+    // The source is now ready for compilation. For that, we need to pass the
+    // control back to the embedder, to get Context etc. set up correctly.
+    callback_(source_, callback_data_);
+  }
+
+ private:
+  ScriptCompiler::StreamedSource* source_;
+  Isolate* isolate_;
+  ScriptCompiler::StreamingCompleteCallback callback_;
+  void* callback_data_;
+};
+
+
+void BackgroundParsingTask::Run() {
+  uintptr_t limit =
+      reinterpret_cast<uintptr_t>(&limit) - kBackgroundParserThreadStackSize;
+  Parser parser(source_->info, limit, hash_seed_);
+  parser.set_allow_lazy(allow_lazy_);
+  parser.ParseOnBackground();
+
+  if (script_data_ != NULL) {
+    source_->cached_data = new ScriptCompiler::CachedData(
+        script_data_->data(), script_data_->length(),
+        ScriptCompiler::CachedData::BufferOwned);
+    script_data_->ReleaseDataOwnership();
+    delete script_data_;
+    script_data_ = NULL;
+  }
+
+  // The task is destroyed automatically.
+  V8::GetCurrentPlatform()->CallOnForegroundThread(
+      reinterpret_cast<v8::Isolate*>(isolate_),
+      new FinalizeParsingTask(source_, isolate_, callback_, callback_data_));
+}
+
+
+BackgroundParserThread::BackgroundParserThread()
+    : Thread(Thread::Options("v8::BackgroundParserThread",
+                             kBackgroundParserThreadStackSize)),
+      task_(NULL),
+      have_work_(0),
+      should_stop_(false) {}
+
+
+void BackgroundParserThread::Run() {
+  DisallowHeapAllocation no_allocation;
+  DisallowHandleAllocation no_handles;
+  DisallowHandleDereference no_deref;
+
+  while (true) {
+    have_work_.Wait();
+    if (should_stop_) {
+      break;
+    }
+    DCHECK(task_ != NULL);
+    task_->Run();
+    delete task_;
+    task_ = NULL;
+  }
+}
+
+
+void BackgroundParserThread::Stop() {
+  should_stop_ = true;
+  have_work_.Signal();
+  Join();
+}
+
+
+void BackgroundParserThread::SetTask(BackgroundParsingTask* task) {
+  // This can only be called when the thread is not already running a task. The
+  // upper layer will take care of not tryng to add a task before the previous
+  // one is done. TODO(marja): In the future we'll we want to parse multiple
+  // scripts on the background. We might need several background threads to
+  // distribute the tasks to.
+  DCHECK(task_ == NULL);
+  task_ = task;
+  have_work_.Signal();
+}
+}
+}  // namespace v8::internal