Add support for idle tasks to the default platform

src/libplatform/default-platform.cc

 // Copyright 2013 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/libplatform/default-platform.h"
 
 #include <algorithm>
 #include <queue>
 
 #include "include/libplatform/libplatform.h"
@@ skipping 12 matching lines @@
   platform->SetThreadPoolSize(thread_pool_size);
   platform->EnsureInitialized();
   return platform;
 }
 
 
 bool PumpMessageLoop(v8::Platform* platform, v8::Isolate* isolate) {
   return reinterpret_cast<DefaultPlatform*>(platform)->PumpMessageLoop(isolate);
 }
 
+void RunIdleTasks(v8::Platform* platform, v8::Isolate* isolate,
+                  double idle_time_in_seconds) {
+  reinterpret_cast<DefaultPlatform*>(platform)->RunIdleTasks(
+      isolate, idle_time_in_seconds);
+}
+
 void SetTracingController(
     v8::Platform* platform,
     v8::platform::tracing::TracingController* tracing_controller) {
   return reinterpret_cast<DefaultPlatform*>(platform)->SetTracingController(
       tracing_controller);
 }
 
 const int DefaultPlatform::kMaxThreadPoolSize = 8;
 
 DefaultPlatform::DefaultPlatform()
@@ skipping 19 matching lines @@
       i->second.pop();
     }
   }
   for (auto i = main_thread_delayed_queue_.begin();
        i != main_thread_delayed_queue_.end(); ++i) {
     while (!i->second.empty()) {
       delete i->second.top().second;
       i->second.pop();
     }
   }
+  for (auto& i : main_thread_idle_queue_) {
+    while (!i.second.empty()) {
+      delete i.second.front();
+      i.second.pop();
+    }
+  }
 }
 
 
 void DefaultPlatform::SetThreadPoolSize(int thread_pool_size) {
   base::LockGuard<base::Mutex> guard(&lock_);
   DCHECK(thread_pool_size >= 0);
   if (thread_pool_size < 1) {
     thread_pool_size = base::SysInfo::NumberOfProcessors() - 1;
   }
   thread_pool_size_ =
@@ skipping 29 matching lines @@
   }
   double now = MonotonicallyIncreasingTime();
   std::pair<double, Task*> deadline_and_task = it->second.top();
   if (deadline_and_task.first > now) {
     return NULL;
   }
   it->second.pop();
   return deadline_and_task.second;
 }
 
+IdleTask* DefaultPlatform::PopTaskInMainThreadIdleQueue(v8::Isolate* isolate) {
+  auto it = main_thread_idle_queue_.find(isolate);
+  if (it == main_thread_idle_queue_.end() || it->second.empty()) {
+    return nullptr;
+  }
+  IdleTask* task = it->second.front();
+  it->second.pop();
+  return task;
+}
 
 bool DefaultPlatform::PumpMessageLoop(v8::Isolate* isolate) {
   Task* task = NULL;
   {
     base::LockGuard<base::Mutex> guard(&lock_);
 
     // Move delayed tasks that hit their deadline to the main queue.
     task = PopTaskInMainThreadDelayedQueue(isolate);
     while (task != NULL) {
       main_thread_queue_[isolate].push(task);
       task = PopTaskInMainThreadDelayedQueue(isolate);
     }
 
     task = PopTaskInMainThreadQueue(isolate);
 
     if (task == NULL) {
       return false;
     }
   }
   task->Run();
   delete task;
   return true;
 }
 
+void DefaultPlatform::RunIdleTasks(v8::Isolate* isolate,
+                                   double idle_time_in_seconds) {
+  double deadline_in_seconds =
+      MonotonicallyIncreasingTime() + idle_time_in_seconds;
+  while (deadline_in_seconds > MonotonicallyIncreasingTime()) {
+    {
+      IdleTask* task;
+      {
+        base::LockGuard<base::Mutex> guard(&lock_);
+        task = PopTaskInMainThreadIdleQueue(isolate);
+      }
+      if (task == nullptr) return;
+      task->Run(deadline_in_seconds);
+      delete task;
+    }
+  }
+}
 
-void DefaultPlatform::CallOnBackgroundThread(Task *task,
+void DefaultPlatform::CallOnBackgroundThread(Task* task,
                                              ExpectedRuntime expected_runtime) {
   EnsureInitialized();
   queue_.Append(task);
 }
 
 
 void DefaultPlatform::CallOnForegroundThread(v8::Isolate* isolate, Task* task) {
   base::LockGuard<base::Mutex> guard(&lock_);
   main_thread_queue_[isolate].push(task);
 }
 
 
 void DefaultPlatform::CallDelayedOnForegroundThread(Isolate* isolate,
                                                     Task* task,
                                                     double delay_in_seconds) {
   base::LockGuard<base::Mutex> guard(&lock_);
   double deadline = MonotonicallyIncreasingTime() + delay_in_seconds;
   main_thread_delayed_queue_[isolate].push(std::make_pair(deadline, task));
 }
 
-
 void DefaultPlatform::CallIdleOnForegroundThread(Isolate* isolate,
                                                  IdleTask* task) {
-  UNREACHABLE();
+  base::LockGuard<base::Mutex> guard(&lock_);
+  main_thread_idle_queue_[isolate].push(task);
 }
 
-
-bool DefaultPlatform::IdleTasksEnabled(Isolate* isolate) { return false; }
-
+bool DefaultPlatform::IdleTasksEnabled(Isolate* isolate) { return true; }
 
 double DefaultPlatform::MonotonicallyIncreasingTime() {
   return base::TimeTicks::HighResolutionNow().ToInternalValue() /
          static_cast<double>(base::Time::kMicrosecondsPerSecond);
 }
 
 uint64_t DefaultPlatform::AddTraceEvent(
     char phase, const uint8_t* category_enabled_flag, const char* name,
     const char* scope, uint64_t id, uint64_t bind_id, int num_args,
     const char** arg_names, const uint8_t* arg_types,
@@ skipping 46 matching lines @@
   tracing_controller_->AddTraceStateObserver(observer);
 }
 
 void DefaultPlatform::RemoveTraceStateObserver(TraceStateObserver* observer) {
   if (!tracing_controller_) return;
   tracing_controller_->RemoveTraceStateObserver(observer);
 }
 
 }  // namespace platform
 }  // namespace v8