1 files changed, 356 insertions, 0 deletions
diff --git a/gfx/angle/checkout/src/libANGLE/WorkerThread.cpp b/gfx/angle/checkout/src/libANGLE/WorkerThread.cpp
new file mode 100644
index 0000000000..30c454dd26
--- /dev/null
+++ b/gfx/angle/checkout/src/libANGLE/WorkerThread.cpp
@@ -0,0 +1,356 @@
+//
+// Copyright 2016 The ANGLE 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.
+//
+// WorkerThread:
+//   Task running thread for ANGLE, similar to a TaskRunner in Chromium.
+//   Might be implemented differently depending on platform.
+//
+
+#include "libANGLE/WorkerThread.h"
+
+#include "libANGLE/trace.h"
+
+#if (ANGLE_DELEGATE_WORKERS == ANGLE_ENABLED) || (ANGLE_STD_ASYNC_WORKERS == ANGLE_ENABLED)
+#    include <condition_variable>
+#    include <future>
+#    include <mutex>
+#    include <queue>
+#    include <thread>
+#endif  // (ANGLE_DELEGATE_WORKERS == ANGLE_ENABLED) || (ANGLE_STD_ASYNC_WORKERS == ANGLE_ENABLED)
+
+namespace angle
+{
+
+WaitableEvent::WaitableEvent()  = default;
+WaitableEvent::~WaitableEvent() = default;
+
+void WaitableEventDone::wait() {}
+
+bool WaitableEventDone::isReady()
+{
+    return true;
+}
+
+WorkerThreadPool::WorkerThreadPool()  = default;
+WorkerThreadPool::~WorkerThreadPool() = default;
+
+class SingleThreadedWaitableEvent final : public WaitableEvent
+{
+  public:
+    SingleThreadedWaitableEvent()           = default;
+    ~SingleThreadedWaitableEvent() override = default;
+
+    void wait() override;
+    bool isReady() override;
+};
+
+void SingleThreadedWaitableEvent::wait() {}
+
+bool SingleThreadedWaitableEvent::isReady()
+{
+    return true;
+}
+
+class SingleThreadedWorkerPool final : public WorkerThreadPool
+{
+  public:
+    std::shared_ptr<WaitableEvent> postWorkerTask(std::shared_ptr<Closure> task) override;
+    void setMaxThreads(size_t maxThreads) override;
+    bool isAsync() override;
+};
+
+// SingleThreadedWorkerPool implementation.
+std::shared_ptr<WaitableEvent> SingleThreadedWorkerPool::postWorkerTask(
+    std::shared_ptr<Closure> task)
+{
+    (*task)();
+    return std::make_shared<SingleThreadedWaitableEvent>();
+}
+
+void SingleThreadedWorkerPool::setMaxThreads(size_t maxThreads) {}
+
+bool SingleThreadedWorkerPool::isAsync()
+{
+    return false;
+}
+
+#if (ANGLE_STD_ASYNC_WORKERS == ANGLE_ENABLED)
+class AsyncWaitableEvent final : public WaitableEvent
+{
+  public:
+    AsyncWaitableEvent() : mIsPending(true) {}
+    ~AsyncWaitableEvent() override = default;
+
+    void wait() override;
+    bool isReady() override;
+
+  private:
+    friend class AsyncWorkerPool;
+    void setFuture(std::future<void> &&future);
+
+    // To block wait() when the task is still in queue to be run.
+    // Also to protect the concurrent accesses from both main thread and
+    // background threads to the member fields.
+    std::mutex mMutex;
+
+    bool mIsPending;
+    std::condition_variable mCondition;
+    std::future<void> mFuture;
+};
+
+void AsyncWaitableEvent::setFuture(std::future<void> &&future)
+{
+    mFuture = std::move(future);
+}
+
+void AsyncWaitableEvent::wait()
+{
+    ANGLE_TRACE_EVENT0("gpu.angle", "AsyncWaitableEvent::wait");
+    {
+        std::unique_lock<std::mutex> lock(mMutex);
+        mCondition.wait(lock, [this] { return !mIsPending; });
+    }
+
+    ASSERT(mFuture.valid());
+    mFuture.wait();
+}
+
+bool AsyncWaitableEvent::isReady()
+{
+    std::lock_guard<std::mutex> lock(mMutex);
+    if (mIsPending)
+    {
+        return false;
+    }
+    ASSERT(mFuture.valid());
+    return mFuture.wait_for(std::chrono::seconds(0)) == std::future_status::ready;
+}
+
+class AsyncWorkerPool final : public WorkerThreadPool
+{
+  public:
+    AsyncWorkerPool(size_t maxThreads) : mMaxThreads(maxThreads), mRunningThreads(0) {}
+    ~AsyncWorkerPool() override = default;
+
+    std::shared_ptr<WaitableEvent> postWorkerTask(std::shared_ptr<Closure> task) override;
+    void setMaxThreads(size_t maxThreads) override;
+    bool isAsync() override;
+
+  private:
+    void checkToRunPendingTasks();
+
+    // To protect the concurrent accesses from both main thread and background
+    // threads to the member fields.
+    std::mutex mMutex;
+
+    size_t mMaxThreads;
+    size_t mRunningThreads;
+    std::queue<std::pair<std::shared_ptr<AsyncWaitableEvent>, std::shared_ptr<Closure>>> mTaskQueue;
+};
+
+// AsyncWorkerPool implementation.
+std::shared_ptr<WaitableEvent> AsyncWorkerPool::postWorkerTask(std::shared_ptr<Closure> task)
+{
+    ASSERT(mMaxThreads > 0);
+
+    auto waitable = std::make_shared<AsyncWaitableEvent>();
+    {
+        std::lock_guard<std::mutex> lock(mMutex);
+        mTaskQueue.push(std::make_pair(waitable, task));
+    }
+    checkToRunPendingTasks();
+    return std::move(waitable);
+}
+
+void AsyncWorkerPool::setMaxThreads(size_t maxThreads)
+{
+    {
+        std::lock_guard<std::mutex> lock(mMutex);
+        mMaxThreads = (maxThreads == 0xFFFFFFFF ? std::thread::hardware_concurrency() : maxThreads);
+    }
+    checkToRunPendingTasks();
+}
+
+bool AsyncWorkerPool::isAsync()
+{
+    return true;
+}
+
+void AsyncWorkerPool::checkToRunPendingTasks()
+{
+    std::lock_guard<std::mutex> lock(mMutex);
+    while (mRunningThreads < mMaxThreads && !mTaskQueue.empty())
+    {
+        auto task = mTaskQueue.front();
+        mTaskQueue.pop();
+        auto waitable = task.first;
+        auto closure  = task.second;
+
+        auto future = std::async(std::launch::async, [closure, this] {
+            {
+                ANGLE_TRACE_EVENT0("gpu.angle", "AsyncWorkerPool::RunTask");
+                (*closure)();
+            }
+            {
+                std::lock_guard<std::mutex> lock(mMutex);
+                ASSERT(mRunningThreads != 0);
+                --mRunningThreads;
+            }
+            checkToRunPendingTasks();
+        });
+
+        ++mRunningThreads;
+
+        {
+            std::lock_guard<std::mutex> waitableLock(waitable->mMutex);
+            waitable->mIsPending = false;
+            waitable->setFuture(std::move(future));
+        }
+        waitable->mCondition.notify_all();
+    }
+}
+#endif  // (ANGLE_STD_ASYNC_WORKERS == ANGLE_ENABLED)
+
+#if (ANGLE_DELEGATE_WORKERS == ANGLE_ENABLED)
+class DelegateWaitableEvent final : public WaitableEvent
+{
+  public:
+    DelegateWaitableEvent()           = default;
+    ~DelegateWaitableEvent() override = default;
+
+    void wait() override;
+    bool isReady() override;
+
+    void markAsReady();
+
+  private:
+    // To protect the concurrent accesses from both main thread and background
+    // threads to the member fields.
+    std::mutex mMutex;
+
+    bool mIsReady = false;
+    std::condition_variable mCondition;
+};
+
+void DelegateWaitableEvent::markAsReady()
+{
+    std::lock_guard<std::mutex> lock(mMutex);
+    mIsReady = true;
+    mCondition.notify_all();
+}
+
+void DelegateWaitableEvent::wait()
+{
+    std::unique_lock<std::mutex> lock(mMutex);
+    mCondition.wait(lock, [this] { return mIsReady; });
+}
+
+bool DelegateWaitableEvent::isReady()
+{
+    std::lock_guard<std::mutex> lock(mMutex);
+    return mIsReady;
+}
+
+class DelegateWorkerPool final : public WorkerThreadPool
+{
+  public:
+    DelegateWorkerPool()           = default;
+    ~DelegateWorkerPool() override = default;
+
+    std::shared_ptr<WaitableEvent> postWorkerTask(std::shared_ptr<Closure> task) override;
+
+    void setMaxThreads(size_t maxThreads) override;
+    bool isAsync() override;
+};
+
+// A function wrapper to execute the closure and to notify the waitable
+// event after the execution.
+class DelegateWorkerTask
+{
+  public:
+    DelegateWorkerTask(std::shared_ptr<Closure> task,
+                       std::shared_ptr<DelegateWaitableEvent> waitable)
+        : mTask(task), mWaitable(waitable)
+    {}
+    DelegateWorkerTask()                     = delete;
+    DelegateWorkerTask(DelegateWorkerTask &) = delete;
+
+    static void RunTask(void *userData)
+    {
+        DelegateWorkerTask *workerTask = static_cast<DelegateWorkerTask *>(userData);
+        (*workerTask->mTask)();
+        workerTask->mWaitable->markAsReady();
+
+        // Delete the task after its execution.
+        delete workerTask;
+    }
+
+  private:
+    ~DelegateWorkerTask() = default;
+
+    std::shared_ptr<Closure> mTask;
+    std::shared_ptr<DelegateWaitableEvent> mWaitable;
+};
+
+std::shared_ptr<WaitableEvent> DelegateWorkerPool::postWorkerTask(std::shared_ptr<Closure> task)
+{
+    auto waitable = std::make_shared<DelegateWaitableEvent>();
+
+    // The task will be deleted by DelegateWorkerTask::RunTask(...) after its execution.
+    DelegateWorkerTask *workerTask = new DelegateWorkerTask(task, waitable);
+    auto *platform                 = ANGLEPlatformCurrent();
+    platform->postWorkerTask(platform, DelegateWorkerTask::RunTask, workerTask);
+
+    return std::move(waitable);
+}
+
+void DelegateWorkerPool::setMaxThreads(size_t maxThreads) {}
+
+bool DelegateWorkerPool::isAsync()
+{
+    return true;
+}
+#endif
+
+// static
+std::shared_ptr<WorkerThreadPool> WorkerThreadPool::Create(bool multithreaded)
+{
+    std::shared_ptr<WorkerThreadPool> pool(nullptr);
+
+#if (ANGLE_DELEGATE_WORKERS == ANGLE_ENABLED)
+    const bool hasPostWorkerTaskImpl = ANGLEPlatformCurrent()->postWorkerTask;
+    if (hasPostWorkerTaskImpl && multithreaded)
+    {
+        pool = std::shared_ptr<WorkerThreadPool>(new DelegateWorkerPool());
+    }
+#endif
+#if (ANGLE_STD_ASYNC_WORKERS == ANGLE_ENABLED)
+    if (!pool && multithreaded)
+    {
+        pool = std::shared_ptr<WorkerThreadPool>(
+            new AsyncWorkerPool(std::thread::hardware_concurrency()));
+    }
+#endif
+    if (!pool)
+    {
+        return std::shared_ptr<WorkerThreadPool>(new SingleThreadedWorkerPool());
+    }
+    return pool;
+}
+
+// static
+std::shared_ptr<WaitableEvent> WorkerThreadPool::PostWorkerTask(
+    std::shared_ptr<WorkerThreadPool> pool,
+    std::shared_ptr<Closure> task)
+{
+    std::shared_ptr<WaitableEvent> event = pool->postWorkerTask(task);
+    if (event.get())
+    {
+        event->setWorkerThreadPool(pool);
+    }
+    return event;
+}
+
+}  // namespace angle