BufferQueue.h revision 6b091c53000c843211c218ce40287a7edca9bc63
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_GUI_BUFFERQUEUE_H 18#define ANDROID_GUI_BUFFERQUEUE_H 19 20#include <EGL/egl.h> 21 22#include <gui/ISurfaceTexture.h> 23 24#include <surfaceflinger/IGraphicBufferAlloc.h> 25#include <ui/GraphicBuffer.h> 26 27#include <utils/String8.h> 28#include <utils/Vector.h> 29#include <utils/threads.h> 30 31namespace android { 32// ---------------------------------------------------------------------------- 33 34class BufferQueue : public BnSurfaceTexture { 35public: 36 enum { MIN_UNDEQUEUED_BUFFERS = 2 }; 37 enum { 38 MIN_ASYNC_BUFFER_SLOTS = MIN_UNDEQUEUED_BUFFERS + 1, 39 MIN_SYNC_BUFFER_SLOTS = MIN_UNDEQUEUED_BUFFERS 40 }; 41 enum { NUM_BUFFER_SLOTS = 32 }; 42 enum { NO_CONNECTED_API = 0 }; 43 44 struct FrameAvailableListener : public virtual RefBase { 45 // onFrameAvailable() is called from queueBuffer() each time an 46 // additional frame becomes available for consumption. This means that 47 // frames that are queued while in asynchronous mode only trigger the 48 // callback if no previous frames are pending. Frames queued while in 49 // synchronous mode always trigger the callback. 50 // 51 // This is called without any lock held and can be called concurrently 52 // by multiple threads. 53 virtual void onFrameAvailable() = 0; 54 }; 55 56 // BufferQueue manages a pool of gralloc memory slots to be used 57 // by producers and consumers. 58 // allowSynchronousMode specifies whether or not synchronous mode can be 59 // enabled. 60 BufferQueue(bool allowSynchronousMode = true); 61 virtual ~BufferQueue(); 62 63 // setBufferCount updates the number of available buffer slots. After 64 // calling this all buffer slots are both unallocated and owned by the 65 // BufferQueue object (i.e. they are not owned by the client). 66 virtual status_t setBufferCount(int bufferCount); 67 68 virtual status_t requestBuffer(int slot, sp<GraphicBuffer>* buf); 69 70 // dequeueBuffer gets the next buffer slot index for the client to use. If a 71 // buffer slot is available then that slot index is written to the location 72 // pointed to by the buf argument and a status of OK is returned. If no 73 // slot is available then a status of -EBUSY is returned and buf is 74 // unmodified. 75 // The width and height parameters must be no greater than the minimum of 76 // GL_MAX_VIEWPORT_DIMS and GL_MAX_TEXTURE_SIZE (see: glGetIntegerv). 77 // An error due to invalid dimensions might not be reported until 78 // updateTexImage() is called. 79 virtual status_t dequeueBuffer(int *buf, uint32_t width, uint32_t height, 80 uint32_t format, uint32_t usage); 81 82 // queueBuffer returns a filled buffer to the BufferQueue. In addition, a 83 // timestamp must be provided for the buffer. The timestamp is in 84 // nanoseconds, and must be monotonically increasing. Its other semantics 85 // (zero point, etc) are client-dependent and should be documented by the 86 // client. 87 virtual status_t queueBuffer(int buf, int64_t timestamp, 88 uint32_t* outWidth, uint32_t* outHeight, uint32_t* outTransform); 89 virtual void cancelBuffer(int buf); 90 virtual status_t setCrop(const Rect& reg); 91 virtual status_t setTransform(uint32_t transform); 92 virtual status_t setScalingMode(int mode); 93 94 // setSynchronousMode set whether dequeueBuffer is synchronous or 95 // asynchronous. In synchronous mode, dequeueBuffer blocks until 96 // a buffer is available, the currently bound buffer can be dequeued and 97 // queued buffers will be retired in order. 98 // The default mode is asynchronous. 99 virtual status_t setSynchronousMode(bool enabled); 100 101 // connect attempts to connect a producer client API to the BufferQueue. 102 // This must be called before any other ISurfaceTexture methods are called 103 // except for getAllocator. 104 // 105 // This method will fail if the connect was previously called on the 106 // BufferQueue and no corresponding disconnect call was made. 107 virtual status_t connect(int api, 108 uint32_t* outWidth, uint32_t* outHeight, uint32_t* outTransform); 109 110 // disconnect attempts to disconnect a producer client API from the 111 // BufferQueue. Calling this method will cause any subsequent calls to other 112 // ISurfaceTexture methods to fail except for getAllocator and connect. 113 // Successfully calling connect after this will allow the other methods to 114 // succeed again. 115 // 116 // This method will fail if the the BufferQueue is not currently 117 // connected to the specified client API. 118 virtual status_t disconnect(int api); 119 120protected: 121 122 // freeBufferLocked frees the resources (both GraphicBuffer and EGLImage) 123 // for the given slot. 124 void freeBufferLocked(int index); 125 126 // freeAllBuffersLocked frees the resources (both GraphicBuffer and 127 // EGLImage) for all slots. 128 void freeAllBuffersLocked(); 129 130 // freeAllBuffersExceptHeadLocked frees the resources (both GraphicBuffer 131 // and EGLImage) for all slots except the head of mQueue 132 void freeAllBuffersExceptHeadLocked(); 133 134 // drainQueueLocked drains the buffer queue if we're in synchronous mode 135 // returns immediately otherwise. It returns NO_INIT if the BufferQueue 136 // became abandoned or disconnected during this call. 137 status_t drainQueueLocked(); 138 139 // drainQueueAndFreeBuffersLocked drains the buffer queue if we're in 140 // synchronous mode and free all buffers. In asynchronous mode, all buffers 141 // are freed except the current buffer. 142 status_t drainQueueAndFreeBuffersLocked(); 143 144 status_t setBufferCountServerLocked(int bufferCount); 145 146 enum { INVALID_BUFFER_SLOT = -1 }; 147 148 struct BufferSlot { 149 150 BufferSlot() 151 : mEglImage(EGL_NO_IMAGE_KHR), 152 mEglDisplay(EGL_NO_DISPLAY), 153 mBufferState(BufferSlot::FREE), 154 mRequestBufferCalled(false), 155 mTransform(0), 156 mScalingMode(NATIVE_WINDOW_SCALING_MODE_FREEZE), 157 mTimestamp(0), 158 mFrameNumber(0), 159 mFence(EGL_NO_SYNC_KHR) { 160 mCrop.makeInvalid(); 161 } 162 163 // mGraphicBuffer points to the buffer allocated for this slot or is NULL 164 // if no buffer has been allocated. 165 sp<GraphicBuffer> mGraphicBuffer; 166 167 // mEglImage is the EGLImage created from mGraphicBuffer. 168 EGLImageKHR mEglImage; 169 170 // mEglDisplay is the EGLDisplay used to create mEglImage. 171 EGLDisplay mEglDisplay; 172 173 // BufferState represents the different states in which a buffer slot 174 // can be. 175 enum BufferState { 176 // FREE indicates that the buffer is not currently being used and 177 // will not be used in the future until it gets dequeued and 178 // subsequently queued by the client. 179 FREE = 0, 180 181 // DEQUEUED indicates that the buffer has been dequeued by the 182 // client, but has not yet been queued or canceled. The buffer is 183 // considered 'owned' by the client, and the server should not use 184 // it for anything. 185 // 186 // Note that when in synchronous-mode (mSynchronousMode == true), 187 // the buffer that's currently attached to the texture may be 188 // dequeued by the client. That means that the current buffer can 189 // be in either the DEQUEUED or QUEUED state. In asynchronous mode, 190 // however, the current buffer is always in the QUEUED state. 191 DEQUEUED = 1, 192 193 // QUEUED indicates that the buffer has been queued by the client, 194 // and has not since been made available for the client to dequeue. 195 // Attaching the buffer to the texture does NOT transition the 196 // buffer away from the QUEUED state. However, in Synchronous mode 197 // the current buffer may be dequeued by the client under some 198 // circumstances. See the note about the current buffer in the 199 // documentation for DEQUEUED. 200 QUEUED = 2, 201 }; 202 203 // mBufferState is the current state of this buffer slot. 204 BufferState mBufferState; 205 206 // mRequestBufferCalled is used for validating that the client did 207 // call requestBuffer() when told to do so. Technically this is not 208 // needed but useful for debugging and catching client bugs. 209 bool mRequestBufferCalled; 210 211 // mCrop is the current crop rectangle for this buffer slot. This gets 212 // set to mNextCrop each time queueBuffer gets called for this buffer. 213 Rect mCrop; 214 215 // mTransform is the current transform flags for this buffer slot. This 216 // gets set to mNextTransform each time queueBuffer gets called for this 217 // slot. 218 uint32_t mTransform; 219 220 // mScalingMode is the current scaling mode for this buffer slot. This 221 // gets set to mNextScalingMode each time queueBuffer gets called for 222 // this slot. 223 uint32_t mScalingMode; 224 225 // mTimestamp is the current timestamp for this buffer slot. This gets 226 // to set by queueBuffer each time this slot is queued. 227 int64_t mTimestamp; 228 229 // mFrameNumber is the number of the queued frame for this slot. 230 uint64_t mFrameNumber; 231 232 // mFence is the EGL sync object that must signal before the buffer 233 // associated with this buffer slot may be dequeued. It is initialized 234 // to EGL_NO_SYNC_KHR when the buffer is created and (optionally, based 235 // on a compile-time option) set to a new sync object in updateTexImage. 236 EGLSyncKHR mFence; 237 }; 238 239 // mSlots is the array of buffer slots that must be mirrored on the client 240 // side. This allows buffer ownership to be transferred between the client 241 // and server without sending a GraphicBuffer over binder. The entire array 242 // is initialized to NULL at construction time, and buffers are allocated 243 // for a slot when requestBuffer is called with that slot's index. 244 BufferSlot mSlots[NUM_BUFFER_SLOTS]; 245 246 247 // mDefaultWidth holds the default width of allocated buffers. It is used 248 // in requestBuffers() if a width and height of zero is specified. 249 uint32_t mDefaultWidth; 250 251 // mDefaultHeight holds the default height of allocated buffers. It is used 252 // in requestBuffers() if a width and height of zero is specified. 253 uint32_t mDefaultHeight; 254 255 // mPixelFormat holds the pixel format of allocated buffers. It is used 256 // in requestBuffers() if a format of zero is specified. 257 uint32_t mPixelFormat; 258 259 // mBufferCount is the number of buffer slots that the client and server 260 // must maintain. It defaults to MIN_ASYNC_BUFFER_SLOTS and can be changed 261 // by calling setBufferCount or setBufferCountServer 262 int mBufferCount; 263 264 // mClientBufferCount is the number of buffer slots requested by the client. 265 // The default is zero, which means the client doesn't care how many buffers 266 // there is. 267 int mClientBufferCount; 268 269 // mServerBufferCount buffer count requested by the server-side 270 int mServerBufferCount; 271 272 // mCurrentTexture is the buffer slot index of the buffer that is currently 273 // bound to the OpenGL texture. It is initialized to INVALID_BUFFER_SLOT, 274 // indicating that no buffer slot is currently bound to the texture. Note, 275 // however, that a value of INVALID_BUFFER_SLOT does not necessarily mean 276 // that no buffer is bound to the texture. A call to setBufferCount will 277 // reset mCurrentTexture to INVALID_BUFFER_SLOT. 278 int mCurrentTexture; 279 280 // mNextCrop is the crop rectangle that will be used for the next buffer 281 // that gets queued. It is set by calling setCrop. 282 Rect mNextCrop; 283 284 // mNextTransform is the transform identifier that will be used for the next 285 // buffer that gets queued. It is set by calling setTransform. 286 uint32_t mNextTransform; 287 288 // mNextScalingMode is the scaling mode that will be used for the next 289 // buffers that get queued. It is set by calling setScalingMode. 290 int mNextScalingMode; 291 292 // mGraphicBufferAlloc is the connection to SurfaceFlinger that is used to 293 // allocate new GraphicBuffer objects. 294 sp<IGraphicBufferAlloc> mGraphicBufferAlloc; 295 296 // mFrameAvailableListener is the listener object that will be called when a 297 // new frame becomes available. If it is not NULL it will be called from 298 // queueBuffer. 299 sp<FrameAvailableListener> mFrameAvailableListener; 300 301 // mSynchronousMode whether we're in synchronous mode or not 302 bool mSynchronousMode; 303 304 // mAllowSynchronousMode whether we allow synchronous mode or not 305 const bool mAllowSynchronousMode; 306 307 // mConnectedApi indicates the API that is currently connected to this 308 // BufferQueue. It defaults to NO_CONNECTED_API (= 0), and gets updated 309 // by the connect and disconnect methods. 310 int mConnectedApi; 311 312 // mDequeueCondition condition used for dequeueBuffer in synchronous mode 313 mutable Condition mDequeueCondition; 314 315 // mQueue is a FIFO of queued buffers used in synchronous mode 316 typedef Vector<int> Fifo; 317 Fifo mQueue; 318 319 // mAbandoned indicates that the BufferQueue will no longer be used to 320 // consume images buffers pushed to it using the ISurfaceTexture interface. 321 // It is initialized to false, and set to true in the abandon method. A 322 // BufferQueue that has been abandoned will return the NO_INIT error from 323 // all ISurfaceTexture methods capable of returning an error. 324 bool mAbandoned; 325 326 // mName is a string used to identify the BufferQueue in log messages. 327 // It is set by the setName method. 328 String8 mName; 329 330 // mMutex is the mutex used to prevent concurrent access to the member 331 // variables of BufferQueue objects. It must be locked whenever the 332 // member variables are accessed. 333 mutable Mutex mMutex; 334 335 // mFrameCounter is the free running counter, incremented for every buffer queued 336 // with the surface Texture. 337 uint64_t mFrameCounter; 338}; 339 340// ---------------------------------------------------------------------------- 341}; // namespace android 342 343#endif // ANDROID_GUI_BUFFERQUEUE_H 344