1/*
2 * Copyright (C) 2012 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#ifndef ANDROID_FENCE_H
18#define ANDROID_FENCE_H
19
20#include <stdint.h>
21#include <sys/types.h>
22
23#include <ui/ANativeObjectBase.h>
24#include <ui/PixelFormat.h>
25#include <ui/Rect.h>
26#include <utils/Flattenable.h>
27#include <utils/String8.h>
28
29struct ANativeWindowBuffer;
30
31namespace android {
32
33// ===========================================================================
34// Fence
35// ===========================================================================
36
37class Fence
38    : public LightRefBase<Fence>, public Flattenable
39{
40public:
41    static const sp<Fence> NO_FENCE;
42
43    // Construct a new Fence object with an invalid file descriptor.  This
44    // should be done when the Fence object will be set up by unflattening
45    // serialized data.
46    Fence();
47
48    // Construct a new Fence object to manage a given fence file descriptor.
49    // When the new Fence object is destructed the file descriptor will be
50    // closed.
51    Fence(int fenceFd);
52
53    // Check whether the Fence has an open fence file descriptor. Most Fence
54    // methods treat an invalid file descriptor just like a valid fence that
55    // is already signalled, so using this is usually not necessary.
56    bool isValid() const { return mFenceFd != -1; }
57
58    // wait waits for up to timeout milliseconds for the fence to signal.  If
59    // the fence signals then NO_ERROR is returned. If the timeout expires
60    // before the fence signals then -ETIME is returned.  A timeout of
61    // TIMEOUT_NEVER may be used to indicate that the call should wait
62    // indefinitely for the fence to signal.
63    status_t wait(unsigned int timeout);
64
65    // waitForever is a convenience function for waiting forever for a fence to
66    // signal (just like wait(TIMEOUT_NEVER)), but issuing an error to the
67    // system log and fence state to the kernel log if the wait lasts longer
68    // than warningTimeout. The logname argument should be a string identifying
69    // the caller and will be included in the log message.
70    status_t waitForever(unsigned int warningTimeout, const char* logname);
71
72    // TIMEOUT_NEVER may be passed to the wait method to indicate that it
73    // should wait indefinitely for the fence to signal.
74    enum { TIMEOUT_NEVER = -1 };
75
76    // merge combines two Fence objects, creating a new Fence object that
77    // becomes signaled when both f1 and f2 are signaled (even if f1 or f2 is
78    // destroyed before it becomes signaled).  The name argument specifies the
79    // human-readable name to associated with the new Fence object.
80    static sp<Fence> merge(const String8& name, const sp<Fence>& f1,
81            const sp<Fence>& f2);
82
83    // Return a duplicate of the fence file descriptor. The caller is
84    // responsible for closing the returned file descriptor. On error, -1 will
85    // be returned and errno will indicate the problem.
86    int dup() const;
87
88    // Flattenable interface
89    size_t getFlattenedSize() const;
90    size_t getFdCount() const;
91    status_t flatten(void* buffer, size_t size,
92            int fds[], size_t count) const;
93    status_t unflatten(void const* buffer, size_t size,
94            int fds[], size_t count);
95
96private:
97    // Only allow instantiation using ref counting.
98    friend class LightRefBase<Fence>;
99    virtual ~Fence();
100
101    // Disallow copying
102    Fence(const Fence& rhs);
103    Fence& operator = (const Fence& rhs);
104    const Fence& operator = (const Fence& rhs) const;
105
106    int mFenceFd;
107};
108
109}; // namespace android
110
111#endif // ANDROID_FENCE_H
112