BufferQueue.h revision 9abe1ebc9575dc5a19bf1dfce6e9b02e03374457
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#include <EGL/eglext.h> 22 23#include <gui/IGraphicBufferAlloc.h> 24#include <gui/ISurfaceTexture.h> 25 26#include <ui/GraphicBuffer.h> 27 28#include <utils/String8.h> 29#include <utils/Vector.h> 30#include <utils/threads.h> 31 32namespace android { 33// ---------------------------------------------------------------------------- 34 35class BufferQueue : public BnSurfaceTexture { 36public: 37 enum { MIN_UNDEQUEUED_BUFFERS = 2 }; 38 enum { 39 MIN_ASYNC_BUFFER_SLOTS = MIN_UNDEQUEUED_BUFFERS + 1, 40 MIN_SYNC_BUFFER_SLOTS = MIN_UNDEQUEUED_BUFFERS 41 }; 42 enum { NUM_BUFFER_SLOTS = 32 }; 43 enum { NO_CONNECTED_API = 0 }; 44 enum { INVALID_BUFFER_SLOT = -1 }; 45 enum { STALE_BUFFER_SLOT = 1 }; 46 47 // ConsumerListener is the interface through which the BufferQueue notifies 48 // the consumer of events that the consumer may wish to react to. Because 49 // the consumer will generally have a mutex that is locked during calls from 50 // teh consumer to the BufferQueue, these calls from the BufferQueue to the 51 // consumer *MUST* be called only when the BufferQueue mutex is NOT locked. 52 struct ConsumerListener : public virtual RefBase { 53 // onFrameAvailable is called from queueBuffer each time an additional 54 // frame becomes available for consumption. This means that frames that 55 // are queued while in asynchronous mode only trigger the callback if no 56 // previous frames are pending. Frames queued while in synchronous mode 57 // always trigger the callback. 58 // 59 // This is called without any lock held and can be called concurrently 60 // by multiple threads. 61 virtual void onFrameAvailable() = 0; 62 63 // onBuffersReleased is called to notify the buffer consumer that the 64 // BufferQueue has released its references to one or more GraphicBuffers 65 // contained in its slots. The buffer consumer should then call 66 // BufferQueue::getReleasedBuffers to retrieve the list of buffers 67 // 68 // This is called without any lock held and can be called concurrently 69 // by multiple threads. 70 virtual void onBuffersReleased() = 0; 71 }; 72 73 // ProxyConsumerListener is a ConsumerListener implementation that keeps a weak 74 // reference to the actual consumer object. It forwards all calls to that 75 // consumer object so long as it exists. 76 // 77 // This class exists to avoid having a circular reference between the 78 // BufferQueue object and the consumer object. The reason this can't be a weak 79 // reference in the BufferQueue class is because we're planning to expose the 80 // consumer side of a BufferQueue as a binder interface, which doesn't support 81 // weak references. 82 class ProxyConsumerListener : public BufferQueue::ConsumerListener { 83 public: 84 85 ProxyConsumerListener(const wp<BufferQueue::ConsumerListener>& consumerListener); 86 virtual ~ProxyConsumerListener(); 87 virtual void onFrameAvailable(); 88 virtual void onBuffersReleased(); 89 90 private: 91 92 // mConsumerListener is a weak reference to the ConsumerListener. This is 93 // the raison d'etre of ProxyConsumerListener. 94 wp<BufferQueue::ConsumerListener> mConsumerListener; 95 }; 96 97 98 // BufferQueue manages a pool of gralloc memory slots to be used 99 // by producers and consumers. 100 // allowSynchronousMode specifies whether or not synchronous mode can be 101 // enabled. 102 BufferQueue(bool allowSynchronousMode = true); 103 virtual ~BufferQueue(); 104 105 virtual int query(int what, int* value); 106 107 // setBufferCount updates the number of available buffer slots. After 108 // calling this all buffer slots are both unallocated and owned by the 109 // BufferQueue object (i.e. they are not owned by the client). 110 virtual status_t setBufferCount(int bufferCount); 111 112 virtual status_t requestBuffer(int slot, sp<GraphicBuffer>* buf); 113 114 // dequeueBuffer gets the next buffer slot index for the client to use. If a 115 // buffer slot is available then that slot index is written to the location 116 // pointed to by the buf argument and a status of OK is returned. If no 117 // slot is available then a status of -EBUSY is returned and buf is 118 // unmodified. 119 // The width and height parameters must be no greater than the minimum of 120 // GL_MAX_VIEWPORT_DIMS and GL_MAX_TEXTURE_SIZE (see: glGetIntegerv). 121 // An error due to invalid dimensions might not be reported until 122 // updateTexImage() is called. 123 virtual status_t dequeueBuffer(int *buf, uint32_t width, uint32_t height, 124 uint32_t format, uint32_t usage); 125 126 // queueBuffer returns a filled buffer to the BufferQueue. In addition, a 127 // timestamp must be provided for the buffer. The timestamp is in 128 // nanoseconds, and must be monotonically increasing. Its other semantics 129 // (zero point, etc) are client-dependent and should be documented by the 130 // client. 131 virtual status_t queueBuffer(int buf, int64_t timestamp, 132 const Rect& crop, int scalingMode, uint32_t transform, 133 uint32_t* outWidth, uint32_t* outHeight, uint32_t* outTransform); 134 virtual void cancelBuffer(int buf); 135 136 // setSynchronousMode set whether dequeueBuffer is synchronous or 137 // asynchronous. In synchronous mode, dequeueBuffer blocks until 138 // a buffer is available, the currently bound buffer can be dequeued and 139 // queued buffers will be retired in order. 140 // The default mode is asynchronous. 141 virtual status_t setSynchronousMode(bool enabled); 142 143 // connect attempts to connect a producer client API to the BufferQueue. 144 // This must be called before any other ISurfaceTexture methods are called 145 // except for getAllocator. 146 // 147 // This method will fail if the connect was previously called on the 148 // BufferQueue and no corresponding disconnect call was made. 149 virtual status_t connect(int api, 150 uint32_t* outWidth, uint32_t* outHeight, uint32_t* outTransform); 151 152 // disconnect attempts to disconnect a producer client API from the 153 // BufferQueue. Calling this method will cause any subsequent calls to other 154 // ISurfaceTexture methods to fail except for getAllocator and connect. 155 // Successfully calling connect after this will allow the other methods to 156 // succeed again. 157 // 158 // This method will fail if the the BufferQueue is not currently 159 // connected to the specified client API. 160 virtual status_t disconnect(int api); 161 162 // dump our state in a String 163 virtual void dump(String8& result) const; 164 virtual void dump(String8& result, const char* prefix, char* buffer, size_t SIZE) const; 165 166 // public facing structure for BufferSlot 167 struct BufferItem { 168 169 BufferItem() 170 : 171 mTransform(0), 172 mScalingMode(NATIVE_WINDOW_SCALING_MODE_FREEZE), 173 mTimestamp(0), 174 mFrameNumber(0), 175 mBuf(INVALID_BUFFER_SLOT) { 176 mCrop.makeInvalid(); 177 } 178 // mGraphicBuffer points to the buffer allocated for this slot or is NULL 179 // if no buffer has been allocated. 180 sp<GraphicBuffer> mGraphicBuffer; 181 182 // mCrop is the current crop rectangle for this buffer slot. 183 Rect mCrop; 184 185 // mTransform is the current transform flags for this buffer slot. 186 uint32_t mTransform; 187 188 // mScalingMode is the current scaling mode for this buffer slot. 189 uint32_t mScalingMode; 190 191 // mTimestamp is the current timestamp for this buffer slot. This gets 192 // to set by queueBuffer each time this slot is queued. 193 int64_t mTimestamp; 194 195 // mFrameNumber is the number of the queued frame for this slot. 196 uint64_t mFrameNumber; 197 198 // buf is the slot index of this buffer 199 int mBuf; 200 201 }; 202 203 // The following public functions is the consumer facing interface 204 205 // acquireBuffer attempts to acquire ownership of the next pending buffer in 206 // the BufferQueue. If no buffer is pending then it returns -EINVAL. If a 207 // buffer is successfully acquired, the information about the buffer is 208 // returned in BufferItem. If the buffer returned had previously been 209 // acquired then the BufferItem::mGraphicBuffer field of buffer is set to 210 // NULL and it is assumed that the consumer still holds a reference to the 211 // buffer. 212 status_t acquireBuffer(BufferItem *buffer); 213 214 // releaseBuffer releases a buffer slot from the consumer back to the 215 // BufferQueue pending a fence sync. 216 // 217 // Note that the dependencies on EGL will be removed once we switch to using 218 // the Android HW Sync HAL. 219 status_t releaseBuffer(int buf, EGLDisplay display, EGLSyncKHR fence); 220 221 // consumerConnect connects a consumer to the BufferQueue. Only one 222 // consumer may be connected, and when that consumer disconnects the 223 // BufferQueue is placed into the "abandoned" state, causing most 224 // interactions with the BufferQueue by the producer to fail. 225 status_t consumerConnect(const sp<ConsumerListener>& consumer); 226 227 // consumerDisconnect disconnects a consumer from the BufferQueue. All 228 // buffers will be freed and the BufferQueue is placed in the "abandoned" 229 // state, causing most interactions with the BufferQueue by the producer to 230 // fail. 231 status_t consumerDisconnect(); 232 233 // getReleasedBuffers sets the value pointed to by slotMask to a bit mask 234 // indicating which buffer slots the have been released by the BufferQueue 235 // but have not yet been released by the consumer. 236 status_t getReleasedBuffers(uint32_t* slotMask); 237 238 // setDefaultBufferSize is used to set the size of buffers returned by 239 // requestBuffers when a with and height of zero is requested. 240 status_t setDefaultBufferSize(uint32_t w, uint32_t h); 241 242 // setBufferCountServer set the buffer count. If the client has requested 243 // a buffer count using setBufferCount, the server-buffer count will 244 // take effect once the client sets the count back to zero. 245 status_t setBufferCountServer(int bufferCount); 246 247 // isSynchronousMode returns whether the SurfaceTexture is currently in 248 // synchronous mode. 249 bool isSynchronousMode() const; 250 251 // setConsumerName sets the name used in logging 252 void setConsumerName(const String8& name); 253 254 // setDefaultBufferFormat allows the BufferQueue to create 255 // GraphicBuffers of a defaultFormat if no format is specified 256 // in dequeueBuffer 257 status_t setDefaultBufferFormat(uint32_t defaultFormat); 258 259 // setConsumerUsageBits will turn on additional usage bits for dequeueBuffer 260 status_t setConsumerUsageBits(uint32_t usage); 261 262 // setTransformHint bakes in rotation to buffers so overlays can be used 263 status_t setTransformHint(uint32_t hint); 264 265private: 266 // freeBufferLocked frees the resources (both GraphicBuffer and EGLImage) 267 // for the given slot. 268 void freeBufferLocked(int index); 269 270 // freeAllBuffersLocked frees the resources (both GraphicBuffer and 271 // EGLImage) for all slots. 272 void freeAllBuffersLocked(); 273 274 // freeAllBuffersExceptHeadLocked frees the resources (both GraphicBuffer 275 // and EGLImage) for all slots except the head of mQueue 276 void freeAllBuffersExceptHeadLocked(); 277 278 // drainQueueLocked drains the buffer queue if we're in synchronous mode 279 // returns immediately otherwise. It returns NO_INIT if the BufferQueue 280 // became abandoned or disconnected during this call. 281 status_t drainQueueLocked(); 282 283 // drainQueueAndFreeBuffersLocked drains the buffer queue if we're in 284 // synchronous mode and free all buffers. In asynchronous mode, all buffers 285 // are freed except the current buffer. 286 status_t drainQueueAndFreeBuffersLocked(); 287 288 status_t setBufferCountServerLocked(int bufferCount); 289 290 struct BufferSlot { 291 292 BufferSlot() 293 : mEglDisplay(EGL_NO_DISPLAY), 294 mBufferState(BufferSlot::FREE), 295 mRequestBufferCalled(false), 296 mTransform(0), 297 mScalingMode(NATIVE_WINDOW_SCALING_MODE_FREEZE), 298 mTimestamp(0), 299 mFrameNumber(0), 300 mFence(EGL_NO_SYNC_KHR), 301 mAcquireCalled(false), 302 mNeedsCleanupOnRelease(false) { 303 mCrop.makeInvalid(); 304 } 305 306 // mGraphicBuffer points to the buffer allocated for this slot or is NULL 307 // if no buffer has been allocated. 308 sp<GraphicBuffer> mGraphicBuffer; 309 310 // mEglDisplay is the EGLDisplay used to create mEglImage. 311 EGLDisplay mEglDisplay; 312 313 // BufferState represents the different states in which a buffer slot 314 // can be. 315 enum BufferState { 316 // FREE indicates that the buffer is not currently being used and 317 // will not be used in the future until it gets dequeued and 318 // subsequently queued by the client. 319 // aka "owned by BufferQueue, ready to be dequeued" 320 FREE = 0, 321 322 // DEQUEUED indicates that the buffer has been dequeued by the 323 // client, but has not yet been queued or canceled. The buffer is 324 // considered 'owned' by the client, and the server should not use 325 // it for anything. 326 // 327 // Note that when in synchronous-mode (mSynchronousMode == true), 328 // the buffer that's currently attached to the texture may be 329 // dequeued by the client. That means that the current buffer can 330 // be in either the DEQUEUED or QUEUED state. In asynchronous mode, 331 // however, the current buffer is always in the QUEUED state. 332 // aka "owned by producer, ready to be queued" 333 DEQUEUED = 1, 334 335 // QUEUED indicates that the buffer has been queued by the client, 336 // and has not since been made available for the client to dequeue. 337 // Attaching the buffer to the texture does NOT transition the 338 // buffer away from the QUEUED state. However, in Synchronous mode 339 // the current buffer may be dequeued by the client under some 340 // circumstances. See the note about the current buffer in the 341 // documentation for DEQUEUED. 342 // aka "owned by BufferQueue, ready to be acquired" 343 QUEUED = 2, 344 345 // aka "owned by consumer, ready to be released" 346 ACQUIRED = 3 347 }; 348 349 // mBufferState is the current state of this buffer slot. 350 BufferState mBufferState; 351 352 // mRequestBufferCalled is used for validating that the client did 353 // call requestBuffer() when told to do so. Technically this is not 354 // needed but useful for debugging and catching client bugs. 355 bool mRequestBufferCalled; 356 357 // mCrop is the current crop rectangle for this buffer slot. 358 Rect mCrop; 359 360 // mTransform is the current transform flags for this buffer slot. 361 uint32_t mTransform; 362 363 // mScalingMode is the current scaling mode for this buffer slot. 364 uint32_t mScalingMode; 365 366 // mTimestamp is the current timestamp for this buffer slot. This gets 367 // to set by queueBuffer each time this slot is queued. 368 int64_t mTimestamp; 369 370 // mFrameNumber is the number of the queued frame for this slot. 371 uint64_t mFrameNumber; 372 373 // mFence is the EGL sync object that must signal before the buffer 374 // associated with this buffer slot may be dequeued. It is initialized 375 // to EGL_NO_SYNC_KHR when the buffer is created and (optionally, based 376 // on a compile-time option) set to a new sync object in updateTexImage. 377 EGLSyncKHR mFence; 378 379 // Indicates whether this buffer has been seen by a consumer yet 380 bool mAcquireCalled; 381 382 // Indicates whether this buffer needs to be cleaned up by consumer 383 bool mNeedsCleanupOnRelease; 384 }; 385 386 // mSlots is the array of buffer slots that must be mirrored on the client 387 // side. This allows buffer ownership to be transferred between the client 388 // and server without sending a GraphicBuffer over binder. The entire array 389 // is initialized to NULL at construction time, and buffers are allocated 390 // for a slot when requestBuffer is called with that slot's index. 391 BufferSlot mSlots[NUM_BUFFER_SLOTS]; 392 393 // mDefaultWidth holds the default width of allocated buffers. It is used 394 // in requestBuffers() if a width and height of zero is specified. 395 uint32_t mDefaultWidth; 396 397 // mDefaultHeight holds the default height of allocated buffers. It is used 398 // in requestBuffers() if a width and height of zero is specified. 399 uint32_t mDefaultHeight; 400 401 // mPixelFormat holds the pixel format of allocated buffers. It is used 402 // in requestBuffers() if a format of zero is specified. 403 uint32_t mPixelFormat; 404 405 // mBufferCount is the number of buffer slots that the client and server 406 // must maintain. It defaults to MIN_ASYNC_BUFFER_SLOTS and can be changed 407 // by calling setBufferCount or setBufferCountServer 408 int mBufferCount; 409 410 // mClientBufferCount is the number of buffer slots requested by the client. 411 // The default is zero, which means the client doesn't care how many buffers 412 // there is. 413 int mClientBufferCount; 414 415 // mServerBufferCount buffer count requested by the server-side 416 int mServerBufferCount; 417 418 // mGraphicBufferAlloc is the connection to SurfaceFlinger that is used to 419 // allocate new GraphicBuffer objects. 420 sp<IGraphicBufferAlloc> mGraphicBufferAlloc; 421 422 // mConsumerListener is used to notify the connected consumer of 423 // asynchronous events that it may wish to react to. It is initially set 424 // to NULL and is written by consumerConnect and consumerDisconnect. 425 sp<ConsumerListener> mConsumerListener; 426 427 // mSynchronousMode whether we're in synchronous mode or not 428 bool mSynchronousMode; 429 430 // mAllowSynchronousMode whether we allow synchronous mode or not 431 const bool mAllowSynchronousMode; 432 433 // mConnectedApi indicates the API that is currently connected to this 434 // BufferQueue. It defaults to NO_CONNECTED_API (= 0), and gets updated 435 // by the connect and disconnect methods. 436 int mConnectedApi; 437 438 // mDequeueCondition condition used for dequeueBuffer in synchronous mode 439 mutable Condition mDequeueCondition; 440 441 // mQueue is a FIFO of queued buffers used in synchronous mode 442 typedef Vector<int> Fifo; 443 Fifo mQueue; 444 445 // mAbandoned indicates that the BufferQueue will no longer be used to 446 // consume images buffers pushed to it using the ISurfaceTexture interface. 447 // It is initialized to false, and set to true in the abandon method. A 448 // BufferQueue that has been abandoned will return the NO_INIT error from 449 // all ISurfaceTexture methods capable of returning an error. 450 bool mAbandoned; 451 452 // mName is a string used to identify the BufferQueue in log messages. 453 // It is set by the setName method. 454 String8 mConsumerName; 455 456 // mMutex is the mutex used to prevent concurrent access to the member 457 // variables of BufferQueue objects. It must be locked whenever the 458 // member variables are accessed. 459 mutable Mutex mMutex; 460 461 // mFrameCounter is the free running counter, incremented for every buffer queued 462 // with the surface Texture. 463 uint64_t mFrameCounter; 464 465 // mBufferHasBeenQueued is true once a buffer has been queued. It is reset 466 // by changing the buffer count. 467 bool mBufferHasBeenQueued; 468 469 // mDefaultBufferFormat can be set so it will override 470 // the buffer format when it isn't specified in dequeueBuffer 471 uint32_t mDefaultBufferFormat; 472 473 // mConsumerUsageBits contains flags the consumer wants for GraphicBuffers 474 uint32_t mConsumerUsageBits; 475 476 // mTransformHint is used to optimize for screen rotations 477 uint32_t mTransformHint; 478}; 479 480// ---------------------------------------------------------------------------- 481}; // namespace android 482 483#endif // ANDROID_GUI_BUFFERQUEUE_H 484