BufferQueue.h revision c777b0b3b9b0ea5d8e378fccde6935765e28e329
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/Fence.h> 27#include <ui/GraphicBuffer.h> 28 29#include <utils/String8.h> 30#include <utils/Vector.h> 31#include <utils/threads.h> 32 33namespace android { 34// ---------------------------------------------------------------------------- 35 36class BufferQueue : public BnSurfaceTexture { 37public: 38 enum { MIN_UNDEQUEUED_BUFFERS = 2 }; 39 enum { NUM_BUFFER_SLOTS = 32 }; 40 enum { NO_CONNECTED_API = 0 }; 41 enum { INVALID_BUFFER_SLOT = -1 }; 42 enum { STALE_BUFFER_SLOT = 1, NO_BUFFER_AVAILABLE }; 43 44 // ConsumerListener is the interface through which the BufferQueue notifies 45 // the consumer of events that the consumer may wish to react to. Because 46 // the consumer will generally have a mutex that is locked during calls from 47 // teh consumer to the BufferQueue, these calls from the BufferQueue to the 48 // consumer *MUST* be called only when the BufferQueue mutex is NOT locked. 49 struct ConsumerListener : public virtual RefBase { 50 // onFrameAvailable is called from queueBuffer each time an additional 51 // frame becomes available for consumption. This means that frames that 52 // are queued while in asynchronous mode only trigger the callback if no 53 // previous frames are pending. Frames queued while in synchronous mode 54 // always trigger the callback. 55 // 56 // This is called without any lock held and can be called concurrently 57 // by multiple threads. 58 virtual void onFrameAvailable() = 0; 59 60 // onBuffersReleased is called to notify the buffer consumer that the 61 // BufferQueue has released its references to one or more GraphicBuffers 62 // contained in its slots. The buffer consumer should then call 63 // BufferQueue::getReleasedBuffers to retrieve the list of buffers 64 // 65 // This is called without any lock held and can be called concurrently 66 // by multiple threads. 67 virtual void onBuffersReleased() = 0; 68 }; 69 70 // ProxyConsumerListener is a ConsumerListener implementation that keeps a weak 71 // reference to the actual consumer object. It forwards all calls to that 72 // consumer object so long as it exists. 73 // 74 // This class exists to avoid having a circular reference between the 75 // BufferQueue object and the consumer object. The reason this can't be a weak 76 // reference in the BufferQueue class is because we're planning to expose the 77 // consumer side of a BufferQueue as a binder interface, which doesn't support 78 // weak references. 79 class ProxyConsumerListener : public BufferQueue::ConsumerListener { 80 public: 81 82 ProxyConsumerListener(const wp<BufferQueue::ConsumerListener>& consumerListener); 83 virtual ~ProxyConsumerListener(); 84 virtual void onFrameAvailable(); 85 virtual void onBuffersReleased(); 86 87 private: 88 89 // mConsumerListener is a weak reference to the ConsumerListener. This is 90 // the raison d'etre of ProxyConsumerListener. 91 wp<BufferQueue::ConsumerListener> mConsumerListener; 92 }; 93 94 95 // BufferQueue manages a pool of gralloc memory slots to be used 96 // by producers and consumers. 97 // allowSynchronousMode specifies whether or not synchronous mode can be 98 // enabled. 99 // bufferCount sets the minimum number of undequeued buffers for this queue 100 BufferQueue(bool allowSynchronousMode = true, 101 int bufferCount = MIN_UNDEQUEUED_BUFFERS, 102 const sp<IGraphicBufferAlloc>& allocator = NULL); 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 // 120 // The fence parameter will be updated to hold the fence associated with 121 // the buffer. The contents of the buffer must not be overwritten until the 122 // fence signals. If the fence is NULL, the buffer may be written 123 // immediately. 124 // 125 // The width and height parameters must be no greater than the minimum of 126 // GL_MAX_VIEWPORT_DIMS and GL_MAX_TEXTURE_SIZE (see: glGetIntegerv). 127 // An error due to invalid dimensions might not be reported until 128 // updateTexImage() is called. 129 virtual status_t dequeueBuffer(int *buf, sp<Fence>& fence, 130 uint32_t width, uint32_t height, uint32_t format, uint32_t usage); 131 132 // queueBuffer returns a filled buffer to the BufferQueue. In addition, a 133 // timestamp must be provided for the buffer. The timestamp is in 134 // nanoseconds, and must be monotonically increasing. Its other semantics 135 // (zero point, etc) are client-dependent and should be documented by the 136 // client. 137 virtual status_t queueBuffer(int buf, 138 const QueueBufferInput& input, QueueBufferOutput* output); 139 140 virtual void cancelBuffer(int buf, sp<Fence> fence); 141 142 // setSynchronousMode set whether dequeueBuffer is synchronous or 143 // asynchronous. In synchronous mode, dequeueBuffer blocks until 144 // a buffer is available, the currently bound buffer can be dequeued and 145 // queued buffers will be retired in order. 146 // The default mode is asynchronous. 147 virtual status_t setSynchronousMode(bool enabled); 148 149 // connect attempts to connect a producer client API to the BufferQueue. 150 // This must be called before any other ISurfaceTexture methods are called 151 // except for getAllocator. 152 // 153 // This method will fail if the connect was previously called on the 154 // BufferQueue and no corresponding disconnect call was made. 155 virtual status_t connect(int api, QueueBufferOutput* output); 156 157 // disconnect attempts to disconnect a producer client API from the 158 // BufferQueue. Calling this method will cause any subsequent calls to other 159 // ISurfaceTexture methods to fail except for getAllocator and connect. 160 // Successfully calling connect after this will allow the other methods to 161 // succeed again. 162 // 163 // This method will fail if the the BufferQueue is not currently 164 // connected to the specified client API. 165 virtual status_t disconnect(int api); 166 167 // dump our state in a String 168 virtual void dump(String8& result) const; 169 virtual void dump(String8& result, const char* prefix, char* buffer, size_t SIZE) const; 170 171 // public facing structure for BufferSlot 172 struct BufferItem { 173 174 BufferItem() 175 : 176 mTransform(0), 177 mScalingMode(NATIVE_WINDOW_SCALING_MODE_FREEZE), 178 mTimestamp(0), 179 mFrameNumber(0), 180 mBuf(INVALID_BUFFER_SLOT) { 181 mCrop.makeInvalid(); 182 } 183 // mGraphicBuffer points to the buffer allocated for this slot or is NULL 184 // if no buffer has been allocated. 185 sp<GraphicBuffer> mGraphicBuffer; 186 187 // mCrop is the current crop rectangle for this buffer slot. 188 Rect mCrop; 189 190 // mTransform is the current transform flags for this buffer slot. 191 uint32_t mTransform; 192 193 // mScalingMode is the current scaling mode for this buffer slot. 194 uint32_t mScalingMode; 195 196 // mTimestamp is the current timestamp for this buffer slot. This gets 197 // to set by queueBuffer each time this slot is queued. 198 int64_t mTimestamp; 199 200 // mFrameNumber is the number of the queued frame for this slot. 201 uint64_t mFrameNumber; 202 203 // mBuf is the slot index of this buffer 204 int mBuf; 205 }; 206 207 // The following public functions is the consumer facing interface 208 209 // acquireBuffer attempts to acquire ownership of the next pending buffer in 210 // the BufferQueue. If no buffer is pending then it returns -EINVAL. If a 211 // buffer is successfully acquired, the information about the buffer is 212 // returned in BufferItem. If the buffer returned had previously been 213 // acquired then the BufferItem::mGraphicBuffer field of buffer is set to 214 // NULL and it is assumed that the consumer still holds a reference to the 215 // buffer. 216 status_t acquireBuffer(BufferItem *buffer); 217 218 // releaseBuffer releases a buffer slot from the consumer back to the 219 // BufferQueue pending a fence sync. 220 // 221 // If releaseBuffer returns STALE_BUFFER_SLOT, then the consumer must free 222 // any references to the just-released buffer that it might have, as if it 223 // had received a onBuffersReleased() call with a mask set for the released 224 // buffer. 225 // 226 // Note that the dependencies on EGL will be removed once we switch to using 227 // the Android HW Sync HAL. 228 status_t releaseBuffer(int buf, EGLDisplay display, EGLSyncKHR fence, 229 const sp<Fence>& releaseFence); 230 231 // consumerConnect connects a consumer to the BufferQueue. Only one 232 // consumer may be connected, and when that consumer disconnects the 233 // BufferQueue is placed into the "abandoned" state, causing most 234 // interactions with the BufferQueue by the producer to fail. 235 status_t consumerConnect(const sp<ConsumerListener>& consumer); 236 237 // consumerDisconnect disconnects a consumer from the BufferQueue. All 238 // buffers will be freed and the BufferQueue is placed in the "abandoned" 239 // state, causing most interactions with the BufferQueue by the producer to 240 // fail. 241 status_t consumerDisconnect(); 242 243 // getReleasedBuffers sets the value pointed to by slotMask to a bit mask 244 // indicating which buffer slots the have been released by the BufferQueue 245 // but have not yet been released by the consumer. 246 status_t getReleasedBuffers(uint32_t* slotMask); 247 248 // setDefaultBufferSize is used to set the size of buffers returned by 249 // requestBuffers when a with and height of zero is requested. 250 status_t setDefaultBufferSize(uint32_t w, uint32_t h); 251 252 // setBufferCountServer set the buffer count. If the client has requested 253 // a buffer count using setBufferCount, the server-buffer count will 254 // take effect once the client sets the count back to zero. 255 status_t setBufferCountServer(int bufferCount); 256 257 // isSynchronousMode returns whether the SurfaceTexture is currently in 258 // synchronous mode. 259 bool isSynchronousMode() const; 260 261 // setConsumerName sets the name used in logging 262 void setConsumerName(const String8& name); 263 264 // setDefaultBufferFormat allows the BufferQueue to create 265 // GraphicBuffers of a defaultFormat if no format is specified 266 // in dequeueBuffer 267 status_t setDefaultBufferFormat(uint32_t defaultFormat); 268 269 // setConsumerUsageBits will turn on additional usage bits for dequeueBuffer 270 status_t setConsumerUsageBits(uint32_t usage); 271 272 // setTransformHint bakes in rotation to buffers so overlays can be used 273 status_t setTransformHint(uint32_t hint); 274 275private: 276 // freeBufferLocked frees the resources (both GraphicBuffer and EGLImage) 277 // for the given slot. 278 void freeBufferLocked(int index); 279 280 // freeAllBuffersLocked frees the resources (both GraphicBuffer and 281 // EGLImage) for all slots. 282 void freeAllBuffersLocked(); 283 284 // freeAllBuffersExceptHeadLocked frees the resources (both GraphicBuffer 285 // and EGLImage) for all slots except the head of mQueue 286 void freeAllBuffersExceptHeadLocked(); 287 288 // drainQueueLocked drains the buffer queue if we're in synchronous mode 289 // returns immediately otherwise. It returns NO_INIT if the BufferQueue 290 // became abandoned or disconnected during this call. 291 status_t drainQueueLocked(); 292 293 // drainQueueAndFreeBuffersLocked drains the buffer queue if we're in 294 // synchronous mode and free all buffers. In asynchronous mode, all buffers 295 // are freed except the current buffer. 296 status_t drainQueueAndFreeBuffersLocked(); 297 298 status_t setBufferCountServerLocked(int bufferCount); 299 300 struct BufferSlot { 301 302 BufferSlot() 303 : mEglDisplay(EGL_NO_DISPLAY), 304 mBufferState(BufferSlot::FREE), 305 mRequestBufferCalled(false), 306 mTransform(0), 307 mScalingMode(NATIVE_WINDOW_SCALING_MODE_FREEZE), 308 mTimestamp(0), 309 mFrameNumber(0), 310 mEglFence(EGL_NO_SYNC_KHR), 311 mAcquireCalled(false), 312 mNeedsCleanupOnRelease(false) { 313 mCrop.makeInvalid(); 314 } 315 316 // mGraphicBuffer points to the buffer allocated for this slot or is NULL 317 // if no buffer has been allocated. 318 sp<GraphicBuffer> mGraphicBuffer; 319 320 // mEglDisplay is the EGLDisplay used to create mEglImage. 321 EGLDisplay mEglDisplay; 322 323 // BufferState represents the different states in which a buffer slot 324 // can be. 325 enum BufferState { 326 // FREE indicates that the buffer is not currently being used and 327 // will not be used in the future until it gets dequeued and 328 // subsequently queued by the client. 329 // aka "owned by BufferQueue, ready to be dequeued" 330 FREE = 0, 331 332 // DEQUEUED indicates that the buffer has been dequeued by the 333 // client, but has not yet been queued or canceled. The buffer is 334 // considered 'owned' by the client, and the server should not use 335 // it for anything. 336 // 337 // Note that when in synchronous-mode (mSynchronousMode == true), 338 // the buffer that's currently attached to the texture may be 339 // dequeued by the client. That means that the current buffer can 340 // be in either the DEQUEUED or QUEUED state. In asynchronous mode, 341 // however, the current buffer is always in the QUEUED state. 342 // aka "owned by producer, ready to be queued" 343 DEQUEUED = 1, 344 345 // QUEUED indicates that the buffer has been queued by the client, 346 // and has not since been made available for the client to dequeue. 347 // Attaching the buffer to the texture does NOT transition the 348 // buffer away from the QUEUED state. However, in Synchronous mode 349 // the current buffer may be dequeued by the client under some 350 // circumstances. See the note about the current buffer in the 351 // documentation for DEQUEUED. 352 // aka "owned by BufferQueue, ready to be acquired" 353 QUEUED = 2, 354 355 // aka "owned by consumer, ready to be released" 356 ACQUIRED = 3 357 }; 358 359 // mBufferState is the current state of this buffer slot. 360 BufferState mBufferState; 361 362 // mRequestBufferCalled is used for validating that the client did 363 // call requestBuffer() when told to do so. Technically this is not 364 // needed but useful for debugging and catching client bugs. 365 bool mRequestBufferCalled; 366 367 // mCrop is the current crop rectangle for this buffer slot. 368 Rect mCrop; 369 370 // mTransform is the current transform flags for this buffer slot. 371 uint32_t mTransform; 372 373 // mScalingMode is the current scaling mode for this buffer slot. 374 uint32_t mScalingMode; 375 376 // mTimestamp is the current timestamp for this buffer slot. This gets 377 // to set by queueBuffer each time this slot is queued. 378 int64_t mTimestamp; 379 380 // mFrameNumber is the number of the queued frame for this slot. 381 uint64_t mFrameNumber; 382 383 // mEglFence is the EGL sync object that must signal before the buffer 384 // associated with this buffer slot may be dequeued. It is initialized 385 // to EGL_NO_SYNC_KHR when the buffer is created and (optionally, based 386 // on a compile-time option) set to a new sync object in updateTexImage. 387 EGLSyncKHR mEglFence; 388 389 // mFence is a fence which will signal when work initiated by the 390 // previous owner of the buffer is finished. When the buffer is FREE, 391 // the fence indicates when the consumer has finished reading 392 // from the buffer, or when the producer has finished writing if it 393 // called cancelBuffer after queueing some writes. When the buffer is 394 // QUEUED, it indicates when the producer has finished filling the 395 // buffer. When the buffer is DEQUEUED or ACQUIRED, the fence has been 396 // passed to the consumer or producer along with ownership of the 397 // buffer, and mFence is empty. 398 sp<Fence> mFence; 399 400 // Indicates whether this buffer has been seen by a consumer yet 401 bool mAcquireCalled; 402 403 // Indicates whether this buffer needs to be cleaned up by consumer 404 bool mNeedsCleanupOnRelease; 405 }; 406 407 // mSlots is the array of buffer slots that must be mirrored on the client 408 // side. This allows buffer ownership to be transferred between the client 409 // and server without sending a GraphicBuffer over binder. The entire array 410 // is initialized to NULL at construction time, and buffers are allocated 411 // for a slot when requestBuffer is called with that slot's index. 412 BufferSlot mSlots[NUM_BUFFER_SLOTS]; 413 414 // mDefaultWidth holds the default width of allocated buffers. It is used 415 // in requestBuffers() if a width and height of zero is specified. 416 uint32_t mDefaultWidth; 417 418 // mDefaultHeight holds the default height of allocated buffers. It is used 419 // in requestBuffers() if a width and height of zero is specified. 420 uint32_t mDefaultHeight; 421 422 // mPixelFormat holds the pixel format of allocated buffers. It is used 423 // in requestBuffers() if a format of zero is specified. 424 uint32_t mPixelFormat; 425 426 // mMinUndequeuedBuffers is a constraint on the number of buffers 427 // not dequeued at any time 428 int mMinUndequeuedBuffers; 429 430 // mMinAsyncBufferSlots is a constraint on the minimum mBufferCount 431 // when this BufferQueue is in asynchronous mode 432 int mMinAsyncBufferSlots; 433 434 // mMinSyncBufferSlots is a constraint on the minimum mBufferCount 435 // when this BufferQueue is in synchronous mode 436 int mMinSyncBufferSlots; 437 438 // mBufferCount is the number of buffer slots that the client and server 439 // must maintain. It defaults to MIN_ASYNC_BUFFER_SLOTS and can be changed 440 // by calling setBufferCount or setBufferCountServer 441 int mBufferCount; 442 443 // mClientBufferCount is the number of buffer slots requested by the client. 444 // The default is zero, which means the client doesn't care how many buffers 445 // there is. 446 int mClientBufferCount; 447 448 // mServerBufferCount buffer count requested by the server-side 449 int mServerBufferCount; 450 451 // mGraphicBufferAlloc is the connection to SurfaceFlinger that is used to 452 // allocate new GraphicBuffer objects. 453 sp<IGraphicBufferAlloc> mGraphicBufferAlloc; 454 455 // mConsumerListener is used to notify the connected consumer of 456 // asynchronous events that it may wish to react to. It is initially set 457 // to NULL and is written by consumerConnect and consumerDisconnect. 458 sp<ConsumerListener> mConsumerListener; 459 460 // mSynchronousMode whether we're in synchronous mode or not 461 bool mSynchronousMode; 462 463 // mAllowSynchronousMode whether we allow synchronous mode or not 464 const bool mAllowSynchronousMode; 465 466 // mConnectedApi indicates the API that is currently connected to this 467 // BufferQueue. It defaults to NO_CONNECTED_API (= 0), and gets updated 468 // by the connect and disconnect methods. 469 int mConnectedApi; 470 471 // mDequeueCondition condition used for dequeueBuffer in synchronous mode 472 mutable Condition mDequeueCondition; 473 474 // mQueue is a FIFO of queued buffers used in synchronous mode 475 typedef Vector<int> Fifo; 476 Fifo mQueue; 477 478 // mAbandoned indicates that the BufferQueue will no longer be used to 479 // consume images buffers pushed to it using the ISurfaceTexture interface. 480 // It is initialized to false, and set to true in the abandon method. A 481 // BufferQueue that has been abandoned will return the NO_INIT error from 482 // all ISurfaceTexture methods capable of returning an error. 483 bool mAbandoned; 484 485 // mName is a string used to identify the BufferQueue in log messages. 486 // It is set by the setName method. 487 String8 mConsumerName; 488 489 // mMutex is the mutex used to prevent concurrent access to the member 490 // variables of BufferQueue objects. It must be locked whenever the 491 // member variables are accessed. 492 mutable Mutex mMutex; 493 494 // mFrameCounter is the free running counter, incremented for every buffer queued 495 // with the surface Texture. 496 uint64_t mFrameCounter; 497 498 // mBufferHasBeenQueued is true once a buffer has been queued. It is reset 499 // by changing the buffer count. 500 bool mBufferHasBeenQueued; 501 502 // mDefaultBufferFormat can be set so it will override 503 // the buffer format when it isn't specified in dequeueBuffer 504 uint32_t mDefaultBufferFormat; 505 506 // mConsumerUsageBits contains flags the consumer wants for GraphicBuffers 507 uint32_t mConsumerUsageBits; 508 509 // mTransformHint is used to optimize for screen rotations 510 uint32_t mTransformHint; 511}; 512 513// ---------------------------------------------------------------------------- 514}; // namespace android 515 516#endif // ANDROID_GUI_BUFFERQUEUE_H 517