xref: /aosp_15_r20/external/webrtc/modules/desktop_capture/shared_memory.h (revision d9f758449e529ab9291ac668be2861e7a55c2422)
1 /*
2  *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
3  *
4  *  Use of this source code is governed by a BSD-style license
5  *  that can be found in the LICENSE file in the root of the source
6  *  tree. An additional intellectual property rights grant can be found
7  *  in the file PATENTS.  All contributing project authors may
8  *  be found in the AUTHORS file in the root of the source tree.
9  */
10 
11 #ifndef MODULES_DESKTOP_CAPTURE_SHARED_MEMORY_H_
12 #define MODULES_DESKTOP_CAPTURE_SHARED_MEMORY_H_
13 
14 #include <stddef.h>
15 
16 #if defined(WEBRTC_WIN)
17 // Forward declare HANDLE in a windows.h compatible way so that we can avoid
18 // including windows.h.
19 typedef void* HANDLE;
20 #endif
21 
22 #include <memory>
23 
24 #include "rtc_base/system/rtc_export.h"
25 
26 namespace webrtc {
27 
28 // SharedMemory is a base class for shared memory. It stores all required
29 // parameters of the buffer, but doesn't have any logic to allocate or destroy
30 // the actual buffer. DesktopCapturer consumers that need to use shared memory
31 // for video frames must extend this class with creation and destruction logic
32 // specific for the target platform and then call
33 // DesktopCapturer::SetSharedMemoryFactory().
34 class RTC_EXPORT SharedMemory {
35  public:
36 #if defined(WEBRTC_WIN)
37   typedef HANDLE Handle;
38   static const Handle kInvalidHandle;
39 #else
40   typedef int Handle;
41   static const Handle kInvalidHandle;
42 #endif
43 
data()44   void* data() const { return data_; }
size()45   size_t size() const { return size_; }
46 
47   // Platform-specific handle of the buffer.
handle()48   Handle handle() const { return handle_; }
49 
50   // Integer identifier that can be used used by consumers of DesktopCapturer
51   // interface to identify shared memory buffers it created.
id()52   int id() const { return id_; }
53 
~SharedMemory()54   virtual ~SharedMemory() {}
55 
56   SharedMemory(const SharedMemory&) = delete;
57   SharedMemory& operator=(const SharedMemory&) = delete;
58 
59  protected:
60   SharedMemory(void* data, size_t size, Handle handle, int id);
61 
62   void* const data_;
63   const size_t size_;
64   const Handle handle_;
65   const int id_;
66 };
67 
68 // Interface used to create SharedMemory instances.
69 class SharedMemoryFactory {
70  public:
SharedMemoryFactory()71   SharedMemoryFactory() {}
~SharedMemoryFactory()72   virtual ~SharedMemoryFactory() {}
73 
74   SharedMemoryFactory(const SharedMemoryFactory&) = delete;
75   SharedMemoryFactory& operator=(const SharedMemoryFactory&) = delete;
76 
77   virtual std::unique_ptr<SharedMemory> CreateSharedMemory(size_t size) = 0;
78 };
79 
80 }  // namespace webrtc
81 
82 #endif  // MODULES_DESKTOP_CAPTURE_SHARED_MEMORY_H_
83