BufferQueue.h revision 1a4d883dcc1725892bfb5c28dec255a233186524
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 // mFence is a fence that will signal when the buffer is idle. 207 sp<Fence> mFence; 208 }; 209 210 // The following public functions is the consumer facing interface 211 212 // acquireBuffer attempts to acquire ownership of the next pending buffer in 213 // the BufferQueue. If no buffer is pending then it returns -EINVAL. If a 214 // buffer is successfully acquired, the information about the buffer is 215 // returned in BufferItem. If the buffer returned had previously been 216 // acquired then the BufferItem::mGraphicBuffer field of buffer is set to 217 // NULL and it is assumed that the consumer still holds a reference to the 218 // buffer. 219 status_t acquireBuffer(BufferItem *buffer); 220 221 // releaseBuffer releases a buffer slot from the consumer back to the 222 // BufferQueue pending a fence sync. 223 // 224 // If releaseBuffer returns STALE_BUFFER_SLOT, then the consumer must free 225 // any references to the just-released buffer that it might have, as if it 226 // had received a onBuffersReleased() call with a mask set for the released 227 // buffer. 228 // 229 // Note that the dependencies on EGL will be removed once we switch to using 230 // the Android HW Sync HAL. 231 status_t releaseBuffer(int buf, EGLDisplay display, EGLSyncKHR fence, 232 const sp<Fence>& releaseFence); 233 234 // consumerConnect connects a consumer to the BufferQueue. Only one 235 // consumer may be connected, and when that consumer disconnects the 236 // BufferQueue is placed into the "abandoned" state, causing most 237 // interactions with the BufferQueue by the producer to fail. 238 status_t consumerConnect(const sp<ConsumerListener>& consumer); 239 240 // consumerDisconnect disconnects a consumer from the BufferQueue. All 241 // buffers will be freed and the BufferQueue is placed in the "abandoned" 242 // state, causing most interactions with the BufferQueue by the producer to 243 // fail. 244 status_t consumerDisconnect(); 245 246 // getReleasedBuffers sets the value pointed to by slotMask to a bit mask 247 // indicating which buffer slots the have been released by the BufferQueue 248 // but have not yet been released by the consumer. 249 status_t getReleasedBuffers(uint32_t* slotMask); 250 251 // setDefaultBufferSize is used to set the size of buffers returned by 252 // requestBuffers when a with and height of zero is requested. 253 status_t setDefaultBufferSize(uint32_t w, uint32_t h); 254 255 // setBufferCountServer set the buffer count. If the client has requested 256 // a buffer count using setBufferCount, the server-buffer count will 257 // take effect once the client sets the count back to zero. 258 status_t setBufferCountServer(int bufferCount); 259 260 // isSynchronousMode returns whether the SurfaceTexture is currently in 261 // synchronous mode. 262 bool isSynchronousMode() const; 263 264 // setConsumerName sets the name used in logging 265 void setConsumerName(const String8& name); 266 267 // setDefaultBufferFormat allows the BufferQueue to create 268 // GraphicBuffers of a defaultFormat if no format is specified 269 // in dequeueBuffer 270 status_t setDefaultBufferFormat(uint32_t defaultFormat); 271 272 // setConsumerUsageBits will turn on additional usage bits for dequeueBuffer 273 status_t setConsumerUsageBits(uint32_t usage); 274 275 // setTransformHint bakes in rotation to buffers so overlays can be used 276 status_t setTransformHint(uint32_t hint); 277 278private: 279 // freeBufferLocked frees the resources (both GraphicBuffer and EGLImage) 280 // for the given slot. 281 void freeBufferLocked(int index); 282 283 // freeAllBuffersLocked frees the resources (both GraphicBuffer and 284 // EGLImage) for all slots. 285 void freeAllBuffersLocked(); 286 287 // freeAllBuffersExceptHeadLocked frees the resources (both GraphicBuffer 288 // and EGLImage) for all slots except the head of mQueue 289 void freeAllBuffersExceptHeadLocked(); 290 291 // drainQueueLocked drains the buffer queue if we're in synchronous mode 292 // returns immediately otherwise. It returns NO_INIT if the BufferQueue 293 // became abandoned or disconnected during this call. 294 status_t drainQueueLocked(); 295 296 // drainQueueAndFreeBuffersLocked drains the buffer queue if we're in 297 // synchronous mode and free all buffers. In asynchronous mode, all buffers 298 // are freed except the current buffer. 299 status_t drainQueueAndFreeBuffersLocked(); 300 301 status_t setBufferCountServerLocked(int bufferCount); 302 303 struct BufferSlot { 304 305 BufferSlot() 306 : mEglDisplay(EGL_NO_DISPLAY), 307 mBufferState(BufferSlot::FREE), 308 mRequestBufferCalled(false), 309 mTransform(0), 310 mScalingMode(NATIVE_WINDOW_SCALING_MODE_FREEZE), 311 mTimestamp(0), 312 mFrameNumber(0), 313 mEglFence(EGL_NO_SYNC_KHR), 314 mAcquireCalled(false), 315 mNeedsCleanupOnRelease(false) { 316 mCrop.makeInvalid(); 317 } 318 319 // mGraphicBuffer points to the buffer allocated for this slot or is NULL 320 // if no buffer has been allocated. 321 sp<GraphicBuffer> mGraphicBuffer; 322 323 // mEglDisplay is the EGLDisplay used to create mEglImage. 324 EGLDisplay mEglDisplay; 325 326 // BufferState represents the different states in which a buffer slot 327 // can be. 328 enum BufferState { 329 // FREE indicates that the buffer is not currently being used and 330 // will not be used in the future until it gets dequeued and 331 // subsequently queued by the client. 332 // aka "owned by BufferQueue, ready to be dequeued" 333 FREE = 0, 334 335 // DEQUEUED indicates that the buffer has been dequeued by the 336 // client, but has not yet been queued or canceled. The buffer is 337 // considered 'owned' by the client, and the server should not use 338 // it for anything. 339 // 340 // Note that when in synchronous-mode (mSynchronousMode == true), 341 // the buffer that's currently attached to the texture may be 342 // dequeued by the client. That means that the current buffer can 343 // be in either the DEQUEUED or QUEUED state. In asynchronous mode, 344 // however, the current buffer is always in the QUEUED state. 345 // aka "owned by producer, ready to be queued" 346 DEQUEUED = 1, 347 348 // QUEUED indicates that the buffer has been queued by the client, 349 // and has not since been made available for the client to dequeue. 350 // Attaching the buffer to the texture does NOT transition the 351 // buffer away from the QUEUED state. However, in Synchronous mode 352 // the current buffer may be dequeued by the client under some 353 // circumstances. See the note about the current buffer in the 354 // documentation for DEQUEUED. 355 // aka "owned by BufferQueue, ready to be acquired" 356 QUEUED = 2, 357 358 // aka "owned by consumer, ready to be released" 359 ACQUIRED = 3 360 }; 361 362 // mBufferState is the current state of this buffer slot. 363 BufferState mBufferState; 364 365 // mRequestBufferCalled is used for validating that the client did 366 // call requestBuffer() when told to do so. Technically this is not 367 // needed but useful for debugging and catching client bugs. 368 bool mRequestBufferCalled; 369 370 // mCrop is the current crop rectangle for this buffer slot. 371 Rect mCrop; 372 373 // mTransform is the current transform flags for this buffer slot. 374 uint32_t mTransform; 375 376 // mScalingMode is the current scaling mode for this buffer slot. 377 uint32_t mScalingMode; 378 379 // mTimestamp is the current timestamp for this buffer slot. This gets 380 // to set by queueBuffer each time this slot is queued. 381 int64_t mTimestamp; 382 383 // mFrameNumber is the number of the queued frame for this slot. 384 uint64_t mFrameNumber; 385 386 // mEglFence is the EGL sync object that must signal before the buffer 387 // associated with this buffer slot may be dequeued. It is initialized 388 // to EGL_NO_SYNC_KHR when the buffer is created and (optionally, based 389 // on a compile-time option) set to a new sync object in updateTexImage. 390 EGLSyncKHR mEglFence; 391 392 // mFence is a fence which will signal when work initiated by the 393 // previous owner of the buffer is finished. When the buffer is FREE, 394 // the fence indicates when the consumer has finished reading 395 // from the buffer, or when the producer has finished writing if it 396 // called cancelBuffer after queueing some writes. When the buffer is 397 // QUEUED, it indicates when the producer has finished filling the 398 // buffer. When the buffer is DEQUEUED or ACQUIRED, the fence has been 399 // passed to the consumer or producer along with ownership of the 400 // buffer, and mFence is empty. 401 sp<Fence> mFence; 402 403 // Indicates whether this buffer has been seen by a consumer yet 404 bool mAcquireCalled; 405 406 // Indicates whether this buffer needs to be cleaned up by consumer 407 bool mNeedsCleanupOnRelease; 408 }; 409 410 // mSlots is the array of buffer slots that must be mirrored on the client 411 // side. This allows buffer ownership to be transferred between the client 412 // and server without sending a GraphicBuffer over binder. The entire array 413 // is initialized to NULL at construction time, and buffers are allocated 414 // for a slot when requestBuffer is called with that slot's index. 415 BufferSlot mSlots[NUM_BUFFER_SLOTS]; 416 417 // mDefaultWidth holds the default width of allocated buffers. It is used 418 // in requestBuffers() if a width and height of zero is specified. 419 uint32_t mDefaultWidth; 420 421 // mDefaultHeight holds the default height of allocated buffers. It is used 422 // in requestBuffers() if a width and height of zero is specified. 423 uint32_t mDefaultHeight; 424 425 // mMinUndequeuedBuffers is a constraint on the number of buffers 426 // not dequeued at any time 427 int mMinUndequeuedBuffers; 428 429 // mMinAsyncBufferSlots is a constraint on the minimum mBufferCount 430 // when this BufferQueue is in asynchronous mode 431 int mMinAsyncBufferSlots; 432 433 // mMinSyncBufferSlots is a constraint on the minimum mBufferCount 434 // when this BufferQueue is in synchronous mode 435 int mMinSyncBufferSlots; 436 437 // mBufferCount is the number of buffer slots that the client and server 438 // must maintain. It defaults to MIN_ASYNC_BUFFER_SLOTS and can be changed 439 // by calling setBufferCount or setBufferCountServer 440 int mBufferCount; 441 442 // mClientBufferCount is the number of buffer slots requested by the client. 443 // The default is zero, which means the client doesn't care how many buffers 444 // there is. 445 int mClientBufferCount; 446 447 // mServerBufferCount buffer count requested by the server-side 448 int mServerBufferCount; 449 450 // mGraphicBufferAlloc is the connection to SurfaceFlinger that is used to 451 // allocate new GraphicBuffer objects. 452 sp<IGraphicBufferAlloc> mGraphicBufferAlloc; 453 454 // mConsumerListener is used to notify the connected consumer of 455 // asynchronous events that it may wish to react to. It is initially set 456 // to NULL and is written by consumerConnect and consumerDisconnect. 457 sp<ConsumerListener> mConsumerListener; 458 459 // mSynchronousMode whether we're in synchronous mode or not 460 bool mSynchronousMode; 461 462 // mAllowSynchronousMode whether we allow synchronous mode or not 463 const bool mAllowSynchronousMode; 464 465 // mConnectedApi indicates the API that is currently connected to this 466 // BufferQueue. It defaults to NO_CONNECTED_API (= 0), and gets updated 467 // by the connect and disconnect methods. 468 int mConnectedApi; 469 470 // mDequeueCondition condition used for dequeueBuffer in synchronous mode 471 mutable Condition mDequeueCondition; 472 473 // mQueue is a FIFO of queued buffers used in synchronous mode 474 typedef Vector<int> Fifo; 475 Fifo mQueue; 476 477 // mAbandoned indicates that the BufferQueue will no longer be used to 478 // consume images buffers pushed to it using the ISurfaceTexture interface. 479 // It is initialized to false, and set to true in the abandon method. A 480 // BufferQueue that has been abandoned will return the NO_INIT error from 481 // all ISurfaceTexture methods capable of returning an error. 482 bool mAbandoned; 483 484 // mName is a string used to identify the BufferQueue in log messages. 485 // It is set by the setName method. 486 String8 mConsumerName; 487 488 // mMutex is the mutex used to prevent concurrent access to the member 489 // variables of BufferQueue objects. It must be locked whenever the 490 // member variables are accessed. 491 mutable Mutex mMutex; 492 493 // mFrameCounter is the free running counter, incremented for every buffer queued 494 // with the surface Texture. 495 uint64_t mFrameCounter; 496 497 // mBufferHasBeenQueued is true once a buffer has been queued. It is reset 498 // by changing the buffer count. 499 bool mBufferHasBeenQueued; 500 501 // mDefaultBufferFormat can be set so it will override 502 // the buffer format when it isn't specified in dequeueBuffer 503 uint32_t mDefaultBufferFormat; 504 505 // mConsumerUsageBits contains flags the consumer wants for GraphicBuffers 506 uint32_t mConsumerUsageBits; 507 508 // mTransformHint is used to optimize for screen rotations 509 uint32_t mTransformHint; 510}; 511 512// ---------------------------------------------------------------------------- 513}; // namespace android 514 515#endif // ANDROID_GUI_BUFFERQUEUE_H 516