1 /*
2  * Copyright (C) 2019 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 
18 #pragma once
19 
20 #include <optional>
21 #include <stdint.h>
22 #include <thread>
23 #include <future>
24 
25 #include <wayland-server-core.h>
26 
27 namespace wayland {
28 
29 // Tracks the buffer associated with a Wayland surface.
30 class Surface {
31  public:
32   Surface() = default;
33   virtual ~Surface() = default;
34 
35   Surface(const Surface& rhs) = delete;
36   Surface& operator=(const Surface& rhs) = delete;
37 
38   Surface(Surface&& rhs) = delete;
39   Surface& operator=(Surface&& rhs) = delete;
40 
41   struct Region {
42     int32_t x;
43     int32_t y;
44     int32_t w;
45     int32_t h;
46   };
47 
48   void SetRegion(const Region& region);
49 
50   // Sets the buffer of the pending frame.
51   void Attach(struct wl_resource* buffer);
52 
53   // Commits the pending frame state.
54   void Commit();
55 
56   using FrameCallbackPackaged =
57     std::packaged_task<void(std::uint32_t /*frame_number*/,
58                             std::uint8_t* /*frame_pixels*/)>;
59 
60   // Registers a callback that should be invoked on the first frame after
61   // the given frame number.
62   void OnFrameAfter(uint32_t frame_number,
63                     FrameCallbackPackaged frame_callback);
64 
65  private:
66   struct State {
67     uint32_t current_frame_number = 0;
68 
69     // The buffer for the current committed frame.
70     struct wl_resource* current_buffer = nullptr;
71 
72     // The buffer for the next frame.
73     struct wl_resource* pending_buffer = nullptr;
74 
75     // The buffers expected dimensions.
76     Region region;
77   };
78 
79   std::mutex state_mutex_;
80   State state_;
81 
82   struct PendingFrameCallback {
83     uint32_t frame_number;
84 
85     FrameCallbackPackaged frame_callback;
86   };
87 
88   std::mutex callback_mutex_;
89   std::optional<PendingFrameCallback> callback_;
90 };
91 
92 }  // namespace wayland