replicant-frameworks_native/include/gui/DisplayEventReceiver.h
Mathias Agopian 3cf199aef6 fix an issue with vsync event delivery
vsync events were sometimes delivered to connected
client who didn't request them. this happened if
another client requested the delivery and that client
was first in the client list.

also fix the vsync test which didn't request any events as
well as DisplayEventReveiver documentation which was misleading
about the necessity to request vsync events.

Change-Id: Ie990fda3f337f8f0042745c4b2cde67936c45686
2012-01-31 16:42:54 -08:00

122 lines
3.4 KiB
C++

/*
* Copyright (C) 2011 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef ANDROID_GUI_DISPLAY_EVENT_H
#define ANDROID_GUI_DISPLAY_EVENT_H
#include <stdint.h>
#include <sys/types.h>
#include <utils/Errors.h>
#include <utils/RefBase.h>
#include <utils/Timers.h>
#include <binder/IInterface.h>
// ----------------------------------------------------------------------------
namespace android {
// ----------------------------------------------------------------------------
class BitTube;
class IDisplayEventConnection;
// ----------------------------------------------------------------------------
class DisplayEventReceiver {
public:
enum {
DISPLAY_EVENT_VSYNC = 'vsyn'
};
struct Event {
struct Header {
uint32_t type;
nsecs_t timestamp;
};
struct VSync {
uint32_t count;
};
Header header;
union {
VSync vsync;
};
};
public:
/*
* DisplayEventReceiver creates and registers an event connection with
* SurfaceFlinger. VSync events are disabled by default. Call setVSyncRate
* or requestNextVsync to receive them.
* Other events start being delivered immediately.
*/
DisplayEventReceiver();
/*
* ~DisplayEventReceiver severs the connection with SurfaceFlinger, new events
* stop being delivered immediately. Note that the queue could have
* some events pending. These will be delivered.
*/
~DisplayEventReceiver();
/*
* initCheck returns the state of DisplayEventReceiver after construction.
*/
status_t initCheck() const;
/*
* getFd returns the file descriptor to use to receive events.
* OWNERSHIP IS RETAINED by DisplayEventReceiver. DO NOT CLOSE this
* file-descriptor.
*/
int getFd() const;
/*
* getEvents reads event from the queue and returns how many events were
* read. Returns 0 if there are no more events or a negative error code.
* If NOT_ENOUGH_DATA is returned, the object has become invalid forever, it
* should be destroyed and getEvents() shouldn't be called again.
*/
ssize_t getEvents(Event* events, size_t count);
/*
* setVsyncRate() sets the Event::VSync delivery rate. A value of
* 1 returns every Event::VSync. A value of 2 returns every other event,
* etc... a value of 0 returns no event unless requestNextVsync() has
* been called.
*/
status_t setVsyncRate(uint32_t count);
/*
* requestNextVsync() schedules the next Event::VSync. It has no effect
* if the vsync rate is > 0.
*/
status_t requestNextVsync();
private:
sp<IDisplayEventConnection> mEventConnection;
sp<BitTube> mDataChannel;
};
// ----------------------------------------------------------------------------
}; // namespace android
#endif // ANDROID_GUI_DISPLAY_EVENT_H