BufferQueue.h revision 3e87601170141229d661df93e2f59e1ced73474b
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 { NUM_BUFFER_SLOTS = 32 }; 39 enum { NO_CONNECTED_API = 0 }; 40 enum { INVALID_BUFFER_SLOT = -1 }; 41 enum { STALE_BUFFER_SLOT = 1, NO_BUFFER_AVAILABLE }; 42 43 // ConsumerListener is the interface through which the BufferQueue notifies 44 // the consumer of events that the consumer may wish to react to. Because 45 // the consumer will generally have a mutex that is locked during calls from 46 // teh consumer to the BufferQueue, these calls from the BufferQueue to the 47 // consumer *MUST* be called only when the BufferQueue mutex is NOT locked. 48 struct ConsumerListener : public virtual RefBase { 49 // onFrameAvailable is called from queueBuffer each time an additional 50 // frame becomes available for consumption. This means that frames that 51 // are queued while in asynchronous mode only trigger the callback if no 52 // previous frames are pending. Frames queued while in synchronous mode 53 // always trigger the callback. 54 // 55 // This is called without any lock held and can be called concurrently 56 // by multiple threads. 57 virtual void onFrameAvailable() = 0; 58 59 // onBuffersReleased is called to notify the buffer consumer that the 60 // BufferQueue has released its references to one or more GraphicBuffers 61 // contained in its slots. The buffer consumer should then call 62 // BufferQueue::getReleasedBuffers to retrieve the list of buffers 63 // 64 // This is called without any lock held and can be called concurrently 65 // by multiple threads. 66 virtual void onBuffersReleased() = 0; 67 }; 68 69 // ProxyConsumerListener is a ConsumerListener implementation that keeps a weak 70 // reference to the actual consumer object. It forwards all calls to that 71 // consumer object so long as it exists. 72 // 73 // This class exists to avoid having a circular reference between the 74 // BufferQueue object and the consumer object. The reason this can't be a weak 75 // reference in the BufferQueue class is because we're planning to expose the 76 // consumer side of a BufferQueue as a binder interface, which doesn't support 77 // weak references. 78 class ProxyConsumerListener : public BufferQueue::ConsumerListener { 79 public: 80 81 ProxyConsumerListener(const wp<BufferQueue::ConsumerListener>& consumerListener); 82 virtual ~ProxyConsumerListener(); 83 virtual void onFrameAvailable(); 84 virtual void onBuffersReleased(); 85 86 private: 87 88 // mConsumerListener is a weak reference to the ConsumerListener. This is 89 // the raison d'etre of ProxyConsumerListener. 90 wp<BufferQueue::ConsumerListener> mConsumerListener; 91 }; 92 93 94 // BufferQueue manages a pool of gralloc memory slots to be used 95 // by producers and consumers. 96 // allowSynchronousMode specifies whether or not synchronous mode can be 97 // enabled. 98 // bufferCount sets the minimum number of undequeued buffers for this queue 99 BufferQueue(bool allowSynchronousMode = true, 100 int bufferCount = MIN_UNDEQUEUED_BUFFERS, 101 const sp<IGraphicBufferAlloc>& allocator = NULL); 102 virtual ~BufferQueue(); 103 104 virtual int query(int what, int* value); 105 106 // setBufferCount updates the number of available buffer slots. After 107 // calling this all buffer slots are both unallocated and owned by the 108 // BufferQueue object (i.e. they are not owned by the client). 109 virtual status_t setBufferCount(int bufferCount); 110 111 virtual status_t requestBuffer(int slot, sp<GraphicBuffer>* buf); 112 113 // dequeueBuffer gets the next buffer slot index for the client to use. If a 114 // buffer slot is available then that slot index is written to the location 115 // pointed to by the buf argument and a status of OK is returned. If no 116 // slot is available then a status of -EBUSY is returned and buf is 117 // unmodified. 118 // The width and height parameters must be no greater than the minimum of 119 // GL_MAX_VIEWPORT_DIMS and GL_MAX_TEXTURE_SIZE (see: glGetIntegerv). 120 // An error due to invalid dimensions might not be reported until 121 // updateTexImage() is called. 122 virtual status_t dequeueBuffer(int *buf, uint32_t width, uint32_t height, 123 uint32_t format, uint32_t usage); 124 125 // queueBuffer returns a filled buffer to the BufferQueue. In addition, a 126 // timestamp must be provided for the buffer. The timestamp is in 127 // nanoseconds, and must be monotonically increasing. Its other semantics 128 // (zero point, etc) are client-dependent and should be documented by the 129 // client. 130 virtual status_t queueBuffer(int buf, 131 const QueueBufferInput& input, QueueBufferOutput* output); 132 133 virtual void cancelBuffer(int buf); 134 135 // setSynchronousMode set whether dequeueBuffer is synchronous or 136 // asynchronous. In synchronous mode, dequeueBuffer blocks until 137 // a buffer is available, the currently bound buffer can be dequeued and 138 // queued buffers will be retired in order. 139 // The default mode is asynchronous. 140 virtual status_t setSynchronousMode(bool enabled); 141 142 // connect attempts to connect a producer client API to the BufferQueue. 143 // This must be called before any other ISurfaceTexture methods are called 144 // except for getAllocator. 145 // 146 // This method will fail if the connect was previously called on the 147 // BufferQueue and no corresponding disconnect call was made. 148 virtual status_t connect(int api, QueueBufferOutput* output); 149 150 // disconnect attempts to disconnect a producer client API from the 151 // BufferQueue. Calling this method will cause any subsequent calls to other 152 // ISurfaceTexture methods to fail except for getAllocator and connect. 153 // Successfully calling connect after this will allow the other methods to 154 // succeed again. 155 // 156 // This method will fail if the the BufferQueue is not currently 157 // connected to the specified client API. 158 virtual status_t disconnect(int api); 159 160 // dump our state in a String 161 virtual void dump(String8& result) const; 162 virtual void dump(String8& result, const char* prefix, char* buffer, size_t SIZE) const; 163 164 // public facing structure for BufferSlot 165 struct BufferItem { 166 167 BufferItem() 168 : 169 mTransform(0), 170 mScalingMode(NATIVE_WINDOW_SCALING_MODE_FREEZE), 171 mTimestamp(0), 172 mFrameNumber(0), 173 mBuf(INVALID_BUFFER_SLOT) { 174 mCrop.makeInvalid(); 175 } 176 // mGraphicBuffer points to the buffer allocated for this slot or is NULL 177 // if no buffer has been allocated. 178 sp<GraphicBuffer> mGraphicBuffer; 179 180 // mCrop is the current crop rectangle for this buffer slot. 181 Rect mCrop; 182 183 // mTransform is the current transform flags for this buffer slot. 184 uint32_t mTransform; 185 186 // mScalingMode is the current scaling mode for this buffer slot. 187 uint32_t mScalingMode; 188 189 // mTimestamp is the current timestamp for this buffer slot. This gets 190 // to set by queueBuffer each time this slot is queued. 191 int64_t mTimestamp; 192 193 // mFrameNumber is the number of the queued frame for this slot. 194 uint64_t mFrameNumber; 195 196 // mBuf is the slot index of this buffer 197 int mBuf; 198 }; 199 200 // The following public functions is the consumer facing interface 201 202 // acquireBuffer attempts to acquire ownership of the next pending buffer in 203 // the BufferQueue. If no buffer is pending then it returns -EINVAL. If a 204 // buffer is successfully acquired, the information about the buffer is 205 // returned in BufferItem. If the buffer returned had previously been 206 // acquired then the BufferItem::mGraphicBuffer field of buffer is set to 207 // NULL and it is assumed that the consumer still holds a reference to the 208 // buffer. 209 status_t acquireBuffer(BufferItem *buffer); 210 211 // releaseBuffer releases a buffer slot from the consumer back to the 212 // BufferQueue pending a fence sync. 213 // 214 // If releaseBuffer returns STALE_BUFFER_SLOT, then the consumer must free 215 // any references to the just-released buffer that it might have, as if it 216 // had received a onBuffersReleased() call with a mask set for the released 217 // buffer. 218 // 219 // Note that the dependencies on EGL will be removed once we switch to using 220 // the Android HW Sync HAL. 221 status_t releaseBuffer(int buf, EGLDisplay display, EGLSyncKHR fence); 222 223 // consumerConnect connects a consumer to the BufferQueue. Only one 224 // consumer may be connected, and when that consumer disconnects the 225 // BufferQueue is placed into the "abandoned" state, causing most 226 // interactions with the BufferQueue by the producer to fail. 227 status_t consumerConnect(const sp<ConsumerListener>& consumer); 228 229 // consumerDisconnect disconnects a consumer from the BufferQueue. All 230 // buffers will be freed and the BufferQueue is placed in the "abandoned" 231 // state, causing most interactions with the BufferQueue by the producer to 232 // fail. 233 status_t consumerDisconnect(); 234 235 // getReleasedBuffers sets the value pointed to by slotMask to a bit mask 236 // indicating which buffer slots the have been released by the BufferQueue 237 // but have not yet been released by the consumer. 238 status_t getReleasedBuffers(uint32_t* slotMask); 239 240 // setDefaultBufferSize is used to set the size of buffers returned by 241 // requestBuffers when a with and height of zero is requested. 242 status_t setDefaultBufferSize(uint32_t w, uint32_t h); 243 244 // setBufferCountServer set the buffer count. If the client has requested 245 // a buffer count using setBufferCount, the server-buffer count will 246 // take effect once the client sets the count back to zero. 247 status_t setBufferCountServer(int bufferCount); 248 249 // isSynchronousMode returns whether the SurfaceTexture is currently in 250 // synchronous mode. 251 bool isSynchronousMode() const; 252 253 // setConsumerName sets the name used in logging 254 void setConsumerName(const String8& name); 255 256 // setDefaultBufferFormat allows the BufferQueue to create 257 // GraphicBuffers of a defaultFormat if no format is specified 258 // in dequeueBuffer 259 status_t setDefaultBufferFormat(uint32_t defaultFormat); 260 261 // setConsumerUsageBits will turn on additional usage bits for dequeueBuffer 262 status_t setConsumerUsageBits(uint32_t usage); 263 264 // setTransformHint bakes in rotation to buffers so overlays can be used 265 status_t setTransformHint(uint32_t hint); 266 267private: 268 // freeBufferLocked frees the resources (both GraphicBuffer and EGLImage) 269 // for the given slot. 270 void freeBufferLocked(int index); 271 272 // freeAllBuffersLocked frees the resources (both GraphicBuffer and 273 // EGLImage) for all slots. 274 void freeAllBuffersLocked(); 275 276 // freeAllBuffersExceptHeadLocked frees the resources (both GraphicBuffer 277 // and EGLImage) for all slots except the head of mQueue 278 void freeAllBuffersExceptHeadLocked(); 279 280 // drainQueueLocked drains the buffer queue if we're in synchronous mode 281 // returns immediately otherwise. It returns NO_INIT if the BufferQueue 282 // became abandoned or disconnected during this call. 283 status_t drainQueueLocked(); 284 285 // drainQueueAndFreeBuffersLocked drains the buffer queue if we're in 286 // synchronous mode and free all buffers. In asynchronous mode, all buffers 287 // are freed except the current buffer. 288 status_t drainQueueAndFreeBuffersLocked(); 289 290 status_t setBufferCountServerLocked(int bufferCount); 291 292 struct BufferSlot { 293 294 BufferSlot() 295 : mEglDisplay(EGL_NO_DISPLAY), 296 mBufferState(BufferSlot::FREE), 297 mRequestBufferCalled(false), 298 mTransform(0), 299 mScalingMode(NATIVE_WINDOW_SCALING_MODE_FREEZE), 300 mTimestamp(0), 301 mFrameNumber(0), 302 mFence(EGL_NO_SYNC_KHR), 303 mAcquireCalled(false), 304 mNeedsCleanupOnRelease(false) { 305 mCrop.makeInvalid(); 306 } 307 308 // mGraphicBuffer points to the buffer allocated for this slot or is NULL 309 // if no buffer has been allocated. 310 sp<GraphicBuffer> mGraphicBuffer; 311 312 // mEglDisplay is the EGLDisplay used to create mEglImage. 313 EGLDisplay mEglDisplay; 314 315 // BufferState represents the different states in which a buffer slot 316 // can be. 317 enum BufferState { 318 // FREE indicates that the buffer is not currently being used and 319 // will not be used in the future until it gets dequeued and 320 // subsequently queued by the client. 321 // aka "owned by BufferQueue, ready to be dequeued" 322 FREE = 0, 323 324 // DEQUEUED indicates that the buffer has been dequeued by the 325 // client, but has not yet been queued or canceled. The buffer is 326 // considered 'owned' by the client, and the server should not use 327 // it for anything. 328 // 329 // Note that when in synchronous-mode (mSynchronousMode == true), 330 // the buffer that's currently attached to the texture may be 331 // dequeued by the client. That means that the current buffer can 332 // be in either the DEQUEUED or QUEUED state. In asynchronous mode, 333 // however, the current buffer is always in the QUEUED state. 334 // aka "owned by producer, ready to be queued" 335 DEQUEUED = 1, 336 337 // QUEUED indicates that the buffer has been queued by the client, 338 // and has not since been made available for the client to dequeue. 339 // Attaching the buffer to the texture does NOT transition the 340 // buffer away from the QUEUED state. However, in Synchronous mode 341 // the current buffer may be dequeued by the client under some 342 // circumstances. See the note about the current buffer in the 343 // documentation for DEQUEUED. 344 // aka "owned by BufferQueue, ready to be acquired" 345 QUEUED = 2, 346 347 // aka "owned by consumer, ready to be released" 348 ACQUIRED = 3 349 }; 350 351 // mBufferState is the current state of this buffer slot. 352 BufferState mBufferState; 353 354 // mRequestBufferCalled is used for validating that the client did 355 // call requestBuffer() when told to do so. Technically this is not 356 // needed but useful for debugging and catching client bugs. 357 bool mRequestBufferCalled; 358 359 // mCrop is the current crop rectangle for this buffer slot. 360 Rect mCrop; 361 362 // mTransform is the current transform flags for this buffer slot. 363 uint32_t mTransform; 364 365 // mScalingMode is the current scaling mode for this buffer slot. 366 uint32_t mScalingMode; 367 368 // mTimestamp is the current timestamp for this buffer slot. This gets 369 // to set by queueBuffer each time this slot is queued. 370 int64_t mTimestamp; 371 372 // mFrameNumber is the number of the queued frame for this slot. 373 uint64_t mFrameNumber; 374 375 // mFence is the EGL sync object that must signal before the buffer 376 // associated with this buffer slot may be dequeued. It is initialized 377 // to EGL_NO_SYNC_KHR when the buffer is created and (optionally, based 378 // on a compile-time option) set to a new sync object in updateTexImage. 379 EGLSyncKHR mFence; 380 381 // Indicates whether this buffer has been seen by a consumer yet 382 bool mAcquireCalled; 383 384 // Indicates whether this buffer needs to be cleaned up by consumer 385 bool mNeedsCleanupOnRelease; 386 }; 387 388 // mSlots is the array of buffer slots that must be mirrored on the client 389 // side. This allows buffer ownership to be transferred between the client 390 // and server without sending a GraphicBuffer over binder. The entire array 391 // is initialized to NULL at construction time, and buffers are allocated 392 // for a slot when requestBuffer is called with that slot's index. 393 BufferSlot mSlots[NUM_BUFFER_SLOTS]; 394 395 // mDefaultWidth holds the default width of allocated buffers. It is used 396 // in requestBuffers() if a width and height of zero is specified. 397 uint32_t mDefaultWidth; 398 399 // mDefaultHeight holds the default height of allocated buffers. It is used 400 // in requestBuffers() if a width and height of zero is specified. 401 uint32_t mDefaultHeight; 402 403 // mPixelFormat holds the pixel format of allocated buffers. It is used 404 // in requestBuffers() if a format of zero is specified. 405 uint32_t mPixelFormat; 406 407 // mMinUndequeuedBuffers is a constraint on the number of buffers 408 // not dequeued at any time 409 int mMinUndequeuedBuffers; 410 411 // mMinAsyncBufferSlots is a constraint on the minimum mBufferCount 412 // when this BufferQueue is in asynchronous mode 413 int mMinAsyncBufferSlots; 414 415 // mMinSyncBufferSlots is a constraint on the minimum mBufferCount 416 // when this BufferQueue is in synchronous mode 417 int mMinSyncBufferSlots; 418 419 // mBufferCount is the number of buffer slots that the client and server 420 // must maintain. It defaults to MIN_ASYNC_BUFFER_SLOTS and can be changed 421 // by calling setBufferCount or setBufferCountServer 422 int mBufferCount; 423 424 // mClientBufferCount is the number of buffer slots requested by the client. 425 // The default is zero, which means the client doesn't care how many buffers 426 // there is. 427 int mClientBufferCount; 428 429 // mServerBufferCount buffer count requested by the server-side 430 int mServerBufferCount; 431 432 // mGraphicBufferAlloc is the connection to SurfaceFlinger that is used to 433 // allocate new GraphicBuffer objects. 434 sp<IGraphicBufferAlloc> mGraphicBufferAlloc; 435 436 // mConsumerListener is used to notify the connected consumer of 437 // asynchronous events that it may wish to react to. It is initially set 438 // to NULL and is written by consumerConnect and consumerDisconnect. 439 sp<ConsumerListener> mConsumerListener; 440 441 // mSynchronousMode whether we're in synchronous mode or not 442 bool mSynchronousMode; 443 444 // mAllowSynchronousMode whether we allow synchronous mode or not 445 const bool mAllowSynchronousMode; 446 447 // mConnectedApi indicates the API that is currently connected to this 448 // BufferQueue. It defaults to NO_CONNECTED_API (= 0), and gets updated 449 // by the connect and disconnect methods. 450 int mConnectedApi; 451 452 // mDequeueCondition condition used for dequeueBuffer in synchronous mode 453 mutable Condition mDequeueCondition; 454 455 // mQueue is a FIFO of queued buffers used in synchronous mode 456 typedef Vector<int> Fifo; 457 Fifo mQueue; 458 459 // mAbandoned indicates that the BufferQueue will no longer be used to 460 // consume images buffers pushed to it using the ISurfaceTexture interface. 461 // It is initialized to false, and set to true in the abandon method. A 462 // BufferQueue that has been abandoned will return the NO_INIT error from 463 // all ISurfaceTexture methods capable of returning an error. 464 bool mAbandoned; 465 466 // mName is a string used to identify the BufferQueue in log messages. 467 // It is set by the setName method. 468 String8 mConsumerName; 469 470 // mMutex is the mutex used to prevent concurrent access to the member 471 // variables of BufferQueue objects. It must be locked whenever the 472 // member variables are accessed. 473 mutable Mutex mMutex; 474 475 // mFrameCounter is the free running counter, incremented for every buffer queued 476 // with the surface Texture. 477 uint64_t mFrameCounter; 478 479 // mBufferHasBeenQueued is true once a buffer has been queued. It is reset 480 // by changing the buffer count. 481 bool mBufferHasBeenQueued; 482 483 // mDefaultBufferFormat can be set so it will override 484 // the buffer format when it isn't specified in dequeueBuffer 485 uint32_t mDefaultBufferFormat; 486 487 // mConsumerUsageBits contains flags the consumer wants for GraphicBuffers 488 uint32_t mConsumerUsageBits; 489 490 // mTransformHint is used to optimize for screen rotations 491 uint32_t mTransformHint; 492}; 493 494// ---------------------------------------------------------------------------- 495}; // namespace android 496 497#endif // ANDROID_GUI_BUFFERQUEUE_H 498