1 /*
2  * Copyright 2014 Google Inc.
3  *
4  * Use of this source code is governed by a BSD-style license that can be
5  * found in the LICENSE file.
6  */
7 
8 #ifndef SkTaskGroup_DEFINED
9 #define SkTaskGroup_DEFINED
10 
11 #include "SkExecutor.h"
12 #include "SkNoncopyable.h"
13 #include "SkTypes.h"
14 #include <atomic>
15 #include <functional>
16 
17 class SkTaskGroup : SkNoncopyable {
18 public:
19     // Tasks added to this SkTaskGroup will run on its executor.
20     explicit SkTaskGroup(SkExecutor& executor = SkExecutor::GetDefault());
~SkTaskGroup()21     ~SkTaskGroup() { this->wait(); }
22 
23     // Add a task to this SkTaskGroup.
24     void add(std::function<void(void)> fn);
25 
26     // Add a batch of N tasks, all calling fn with different arguments.
27     void batch(int N, std::function<void(int)> fn);
28 
29     // Returns true if all Tasks previously add()ed to this SkTaskGroup have run.
30     // It is safe to reuse this SkTaskGroup once done().
31     bool done() const;
32 
33     // Block until done().
34     void wait();
35 
36     // A convenience for testing tools.
37     // Creates and owns a thread pool, and passes it to SkExecutor::SetDefault().
38     struct Enabler {
39         explicit Enabler(int threads = -1);  // -1 -> num_cores, 0 -> noop
40         std::unique_ptr<SkExecutor> fThreadPool;
41     };
42 
43 private:
44     std::atomic<int32_t> fPending;
45     SkExecutor&          fExecutor;
46 };
47 
48 #endif//SkTaskGroup_DEFINED
49