BufferQueue.h revision ad678e18b66f495efa78dc3b9ab99b579945c9e2
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/IGraphicBufferProducer.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 BnGraphicBufferProducer { 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, PRESENT_LATER }; 43 44 // When in async mode we reserve two slots in order to guarantee that the 45 // producer and consumer can run asynchronously. 46 enum { MAX_MAX_ACQUIRED_BUFFERS = NUM_BUFFER_SLOTS - 2 }; 47 48 // ConsumerListener is the interface through which the BufferQueue notifies 49 // the consumer of events that the consumer may wish to react to. Because 50 // the consumer will generally have a mutex that is locked during calls from 51 // the consumer to the BufferQueue, these calls from the BufferQueue to the 52 // consumer *MUST* be called only when the BufferQueue mutex is NOT locked. 53 struct ConsumerListener : public virtual RefBase { 54 // onFrameAvailable is called from queueBuffer each time an additional 55 // frame becomes available for consumption. This means that frames that 56 // are queued while in asynchronous mode only trigger the callback if no 57 // previous frames are pending. Frames queued while in synchronous mode 58 // always trigger the callback. 59 // 60 // This is called without any lock held and can be called concurrently 61 // by multiple threads. 62 virtual void onFrameAvailable() = 0; 63 64 // onBuffersReleased is called to notify the buffer consumer that the 65 // BufferQueue has released its references to one or more GraphicBuffers 66 // contained in its slots. The buffer consumer should then call 67 // BufferQueue::getReleasedBuffers to retrieve the list of buffers 68 // 69 // This is called without any lock held and can be called concurrently 70 // by multiple threads. 71 virtual void onBuffersReleased() = 0; 72 }; 73 74 // ProxyConsumerListener is a ConsumerListener implementation that keeps a weak 75 // reference to the actual consumer object. It forwards all calls to that 76 // consumer object so long as it exists. 77 // 78 // This class exists to avoid having a circular reference between the 79 // BufferQueue object and the consumer object. The reason this can't be a weak 80 // reference in the BufferQueue class is because we're planning to expose the 81 // consumer side of a BufferQueue as a binder interface, which doesn't support 82 // weak references. 83 class ProxyConsumerListener : public BufferQueue::ConsumerListener { 84 public: 85 86 ProxyConsumerListener(const wp<BufferQueue::ConsumerListener>& consumerListener); 87 virtual ~ProxyConsumerListener(); 88 virtual void onFrameAvailable(); 89 virtual void onBuffersReleased(); 90 91 private: 92 93 // mConsumerListener is a weak reference to the ConsumerListener. This is 94 // the raison d'etre of ProxyConsumerListener. 95 wp<BufferQueue::ConsumerListener> mConsumerListener; 96 }; 97 98 99 // BufferQueue manages a pool of gralloc memory slots to be used by 100 // producers and consumers. allocator is used to allocate all the 101 // needed gralloc buffers. 102 BufferQueue(const sp<IGraphicBufferAlloc>& allocator = NULL); 103 virtual ~BufferQueue(); 104 105 // Query native window attributes. The "what" values are enumerated in 106 // window.h (e.g. NATIVE_WINDOW_FORMAT). 107 virtual int query(int what, int* value); 108 109 // setBufferCount updates the number of available buffer slots. If this 110 // method succeeds, buffer slots will be both unallocated and owned by 111 // the BufferQueue object (i.e. they are not owned by the producer or 112 // consumer). 113 // 114 // This will fail if the producer has dequeued any buffers, or if 115 // bufferCount is invalid. bufferCount must generally be a value 116 // between the minimum undequeued buffer count and NUM_BUFFER_SLOTS 117 // (inclusive). It may also be set to zero (the default) to indicate 118 // that the producer does not wish to set a value. The minimum value 119 // can be obtained by calling query(NATIVE_WINDOW_MIN_UNDEQUEUED_BUFFERS, 120 // ...). 121 // 122 // This may only be called by the producer. The consumer will be told 123 // to discard buffers through the onBuffersReleased callback. 124 virtual status_t setBufferCount(int bufferCount); 125 126 // requestBuffer returns the GraphicBuffer for slot N. 127 // 128 // In normal operation, this is called the first time slot N is returned 129 // by dequeueBuffer. It must be called again if dequeueBuffer returns 130 // flags indicating that previously-returned buffers are no longer valid. 131 virtual status_t requestBuffer(int slot, sp<GraphicBuffer>* buf); 132 133 // dequeueBuffer gets the next buffer slot index for the producer to use. 134 // If a buffer slot is available then that slot index is written to the 135 // location pointed to by the buf argument and a status of OK is returned. 136 // If no slot is available then a status of -EBUSY is returned and buf is 137 // unmodified. 138 // 139 // The fence parameter will be updated to hold the fence associated with 140 // the buffer. The contents of the buffer must not be overwritten until the 141 // fence signals. If the fence is Fence::NO_FENCE, the buffer may be 142 // written immediately. 143 // 144 // The width and height parameters must be no greater than the minimum of 145 // GL_MAX_VIEWPORT_DIMS and GL_MAX_TEXTURE_SIZE (see: glGetIntegerv). 146 // An error due to invalid dimensions might not be reported until 147 // updateTexImage() is called. If width and height are both zero, the 148 // default values specified by setDefaultBufferSize() are used instead. 149 // 150 // The pixel formats are enumerated in graphics.h, e.g. 151 // HAL_PIXEL_FORMAT_RGBA_8888. If the format is 0, the default format 152 // will be used. 153 // 154 // The usage argument specifies gralloc buffer usage flags. The values 155 // are enumerated in gralloc.h, e.g. GRALLOC_USAGE_HW_RENDER. These 156 // will be merged with the usage flags specified by setConsumerUsageBits. 157 // 158 // The return value may be a negative error value or a non-negative 159 // collection of flags. If the flags are set, the return values are 160 // valid, but additional actions must be performed. 161 // 162 // If IGraphicBufferProducer::BUFFER_NEEDS_REALLOCATION is set, the 163 // producer must discard cached GraphicBuffer references for the slot 164 // returned in buf. 165 // If IGraphicBufferProducer::RELEASE_ALL_BUFFERS is set, the producer 166 // must discard cached GraphicBuffer references for all slots. 167 // 168 // In both cases, the producer will need to call requestBuffer to get a 169 // GraphicBuffer handle for the returned slot. 170 virtual status_t dequeueBuffer(int *buf, sp<Fence>* fence, bool async, 171 uint32_t width, uint32_t height, uint32_t format, uint32_t usage); 172 173 // queueBuffer returns a filled buffer to the BufferQueue. 174 // 175 // Additional data is provided in the QueueBufferInput struct. Notably, 176 // a timestamp must be provided for the buffer. The timestamp is in 177 // nanoseconds, and must be monotonically increasing. Its other semantics 178 // (zero point, etc) are producer-specific and should be documented by the 179 // producer. 180 // 181 // The caller may provide a fence that signals when all rendering 182 // operations have completed. Alternatively, NO_FENCE may be used, 183 // indicating that the buffer is ready immediately. 184 // 185 // Some values are returned in the output struct: the current settings 186 // for default width and height, the current transform hint, and the 187 // number of queued buffers. 188 virtual status_t queueBuffer(int buf, 189 const QueueBufferInput& input, QueueBufferOutput* output); 190 191 // cancelBuffer returns a dequeued buffer to the BufferQueue, but doesn't 192 // queue it for use by the consumer. 193 // 194 // The buffer will not be overwritten until the fence signals. The fence 195 // will usually be the one obtained from dequeueBuffer. 196 virtual void cancelBuffer(int buf, const sp<Fence>& fence); 197 198 // connect attempts to connect a producer API to the BufferQueue. This 199 // must be called before any other IGraphicBufferProducer methods are 200 // called except for getAllocator. A consumer must already be connected. 201 // 202 // This method will fail if connect was previously called on the 203 // BufferQueue and no corresponding disconnect call was made (i.e. if 204 // it's still connected to a producer). 205 // 206 // APIs are enumerated in window.h (e.g. NATIVE_WINDOW_API_CPU). 207 virtual status_t connect(int api, bool producerControlledByApp, QueueBufferOutput* output); 208 209 // disconnect attempts to disconnect a producer API from the BufferQueue. 210 // Calling this method will cause any subsequent calls to other 211 // IGraphicBufferProducer methods to fail except for getAllocator and connect. 212 // Successfully calling connect after this will allow the other methods to 213 // succeed again. 214 // 215 // This method will fail if the the BufferQueue is not currently 216 // connected to the specified producer API. 217 virtual status_t disconnect(int api); 218 219 // dump our state in a String 220 virtual void dump(String8& result) const; 221 virtual void dump(String8& result, const char* prefix) const; 222 223 // public facing structure for BufferSlot 224 struct BufferItem { 225 226 BufferItem() : 227 mTransform(0), 228 mScalingMode(NATIVE_WINDOW_SCALING_MODE_FREEZE), 229 mTimestamp(0), 230 mFrameNumber(0), 231 mBuf(INVALID_BUFFER_SLOT), 232 mIsDroppable(false), 233 mAcquireCalled(false) { 234 mCrop.makeInvalid(); 235 } 236 // mGraphicBuffer points to the buffer allocated for this slot, or is NULL 237 // if the buffer in this slot has been acquired in the past (see 238 // BufferSlot.mAcquireCalled). 239 sp<GraphicBuffer> mGraphicBuffer; 240 241 // mCrop is the current crop rectangle for this buffer slot. 242 Rect mCrop; 243 244 // mTransform is the current transform flags for this buffer slot. 245 uint32_t mTransform; 246 247 // mScalingMode is the current scaling mode for this buffer slot. 248 uint32_t mScalingMode; 249 250 // mTimestamp is the current timestamp for this buffer slot. This gets 251 // to set by queueBuffer each time this slot is queued. 252 int64_t mTimestamp; 253 254 // mFrameNumber is the number of the queued frame for this slot. 255 uint64_t mFrameNumber; 256 257 // mBuf is the slot index of this buffer 258 int mBuf; 259 260 // mFence is a fence that will signal when the buffer is idle. 261 sp<Fence> mFence; 262 263 // mIsDroppable whether this buffer was queued with the 264 // property that it can be replaced by a new buffer for the purpose of 265 // making sure dequeueBuffer() won't block. 266 // i.e.: was the BufferQueue in "mDequeueBufferCannotBlock" when this buffer 267 // was queued. 268 bool mIsDroppable; 269 270 // Indicates whether this buffer has been seen by a consumer yet 271 bool mAcquireCalled; 272 }; 273 274 // The following public functions are the consumer-facing interface 275 276 // acquireBuffer attempts to acquire ownership of the next pending buffer in 277 // the BufferQueue. If no buffer is pending then it returns -EINVAL. If a 278 // buffer is successfully acquired, the information about the buffer is 279 // returned in BufferItem. If the buffer returned had previously been 280 // acquired then the BufferItem::mGraphicBuffer field of buffer is set to 281 // NULL and it is assumed that the consumer still holds a reference to the 282 // buffer. 283 // 284 // If presentWhen is nonzero, it indicates the time when the buffer will 285 // be displayed on screen. If the buffer's timestamp is farther in the 286 // future, the buffer won't be acquired, and PRESENT_LATER will be 287 // returned. The presentation time is in nanoseconds, and the time base 288 // is CLOCK_MONOTONIC. 289 status_t acquireBuffer(BufferItem *buffer, nsecs_t presentWhen); 290 291 // releaseBuffer releases a buffer slot from the consumer back to the 292 // BufferQueue. This may be done while the buffer's contents are still 293 // being accessed. The fence will signal when the buffer is no longer 294 // in use. frameNumber is used to indentify the exact buffer returned. 295 // 296 // If releaseBuffer returns STALE_BUFFER_SLOT, then the consumer must free 297 // any references to the just-released buffer that it might have, as if it 298 // had received a onBuffersReleased() call with a mask set for the released 299 // buffer. 300 // 301 // Note that the dependencies on EGL will be removed once we switch to using 302 // the Android HW Sync HAL. 303 status_t releaseBuffer(int buf, uint64_t frameNumber, 304 EGLDisplay display, EGLSyncKHR fence, 305 const sp<Fence>& releaseFence); 306 307 // consumerConnect connects a consumer to the BufferQueue. Only one 308 // consumer may be connected, and when that consumer disconnects the 309 // BufferQueue is placed into the "abandoned" state, causing most 310 // interactions with the BufferQueue by the producer to fail. 311 // controlledByApp indicates whether the consumer is controlled by 312 // the application. 313 // 314 // consumer may not be NULL. 315 status_t consumerConnect(const sp<ConsumerListener>& consumer, bool controlledByApp); 316 317 // consumerDisconnect disconnects a consumer from the BufferQueue. All 318 // buffers will be freed and the BufferQueue is placed in the "abandoned" 319 // state, causing most interactions with the BufferQueue by the producer to 320 // fail. 321 status_t consumerDisconnect(); 322 323 // getReleasedBuffers sets the value pointed to by slotMask to a bit mask 324 // indicating which buffer slots have been released by the BufferQueue 325 // but have not yet been released by the consumer. 326 // 327 // This should be called from the onBuffersReleased() callback. 328 status_t getReleasedBuffers(uint32_t* slotMask); 329 330 // setDefaultBufferSize is used to set the size of buffers returned by 331 // dequeueBuffer when a width and height of zero is requested. Default 332 // is 1x1. 333 status_t setDefaultBufferSize(uint32_t w, uint32_t h); 334 335 // setDefaultMaxBufferCount sets the default value for the maximum buffer 336 // count (the initial default is 2). If the producer has requested a 337 // buffer count using setBufferCount, the default buffer count will only 338 // take effect if the producer sets the count back to zero. 339 // 340 // The count must be between 2 and NUM_BUFFER_SLOTS, inclusive. 341 status_t setDefaultMaxBufferCount(int bufferCount); 342 343 // disableAsyncBuffer disables the extra buffer used in async mode 344 // (when both producer and consumer have set their "isControlledByApp" 345 // flag) and has dequeueBuffer() return WOULD_BLOCK instead. 346 // 347 // This can only be called before consumerConnect(). 348 status_t disableAsyncBuffer(); 349 350 // setMaxAcquiredBufferCount sets the maximum number of buffers that can 351 // be acquired by the consumer at one time (default 1). This call will 352 // fail if a producer is connected to the BufferQueue. 353 status_t setMaxAcquiredBufferCount(int maxAcquiredBuffers); 354 355 // setConsumerName sets the name used in logging 356 void setConsumerName(const String8& name); 357 358 // setDefaultBufferFormat allows the BufferQueue to create 359 // GraphicBuffers of a defaultFormat if no format is specified 360 // in dequeueBuffer. Formats are enumerated in graphics.h; the 361 // initial default is HAL_PIXEL_FORMAT_RGBA_8888. 362 status_t setDefaultBufferFormat(uint32_t defaultFormat); 363 364 // setConsumerUsageBits will turn on additional usage bits for dequeueBuffer. 365 // These are merged with the bits passed to dequeueBuffer. The values are 366 // enumerated in gralloc.h, e.g. GRALLOC_USAGE_HW_RENDER; the default is 0. 367 status_t setConsumerUsageBits(uint32_t usage); 368 369 // setTransformHint bakes in rotation to buffers so overlays can be used. 370 // The values are enumerated in window.h, e.g. 371 // NATIVE_WINDOW_TRANSFORM_ROT_90. The default is 0 (no transform). 372 status_t setTransformHint(uint32_t hint); 373 374 375private: 376 // freeBufferLocked frees the GraphicBuffer and sync resources for the 377 // given slot. 378 void freeBufferLocked(int index); 379 380 // freeAllBuffersLocked frees the GraphicBuffer and sync resources for 381 // all slots. 382 void freeAllBuffersLocked(); 383 384 // setDefaultMaxBufferCountLocked sets the maximum number of buffer slots 385 // that will be used if the producer does not override the buffer slot 386 // count. The count must be between 2 and NUM_BUFFER_SLOTS, inclusive. 387 // The initial default is 2. 388 status_t setDefaultMaxBufferCountLocked(int count); 389 390 // getMinUndequeuedBufferCount returns the minimum number of buffers 391 // that must remain in a state other than DEQUEUED. 392 // The async parameter tells whether we're in asynchronous mode. 393 int getMinUndequeuedBufferCount(bool async) const; 394 395 // getMinBufferCountLocked returns the minimum number of buffers allowed 396 // given the current BufferQueue state. 397 // The async parameter tells whether we're in asynchronous mode. 398 int getMinMaxBufferCountLocked(bool async) const; 399 400 // getMaxBufferCountLocked returns the maximum number of buffers that can 401 // be allocated at once. This value depends upon the following member 402 // variables: 403 // 404 // mDequeueBufferCannotBlock 405 // mMaxAcquiredBufferCount 406 // mDefaultMaxBufferCount 407 // mOverrideMaxBufferCount 408 // async parameter 409 // 410 // Any time one of these member variables is changed while a producer is 411 // connected, mDequeueCondition must be broadcast. 412 int getMaxBufferCountLocked(bool async) const; 413 414 // stillTracking returns true iff the buffer item is still being tracked 415 // in one of the slots. 416 bool stillTracking(const BufferItem *item) const; 417 418 struct BufferSlot { 419 420 BufferSlot() 421 : mEglDisplay(EGL_NO_DISPLAY), 422 mBufferState(BufferSlot::FREE), 423 mRequestBufferCalled(false), 424 mFrameNumber(0), 425 mEglFence(EGL_NO_SYNC_KHR), 426 mAcquireCalled(false), 427 mNeedsCleanupOnRelease(false) { 428 } 429 430 // mGraphicBuffer points to the buffer allocated for this slot or is NULL 431 // if no buffer has been allocated. 432 sp<GraphicBuffer> mGraphicBuffer; 433 434 // mEglDisplay is the EGLDisplay used to create EGLSyncKHR objects. 435 EGLDisplay mEglDisplay; 436 437 // BufferState represents the different states in which a buffer slot 438 // can be. All slots are initially FREE. 439 enum BufferState { 440 // FREE indicates that the buffer is available to be dequeued 441 // by the producer. The buffer may be in use by the consumer for 442 // a finite time, so the buffer must not be modified until the 443 // associated fence is signaled. 444 // 445 // The slot is "owned" by BufferQueue. It transitions to DEQUEUED 446 // when dequeueBuffer is called. 447 FREE = 0, 448 449 // DEQUEUED indicates that the buffer has been dequeued by the 450 // producer, but has not yet been queued or canceled. The 451 // producer may modify the buffer's contents as soon as the 452 // associated ready fence is signaled. 453 // 454 // The slot is "owned" by the producer. It can transition to 455 // QUEUED (via queueBuffer) or back to FREE (via cancelBuffer). 456 DEQUEUED = 1, 457 458 // QUEUED indicates that the buffer has been filled by the 459 // producer and queued for use by the consumer. The buffer 460 // contents may continue to be modified for a finite time, so 461 // the contents must not be accessed until the associated fence 462 // is signaled. 463 // 464 // The slot is "owned" by BufferQueue. It can transition to 465 // ACQUIRED (via acquireBuffer) or to FREE (if another buffer is 466 // queued in asynchronous mode). 467 QUEUED = 2, 468 469 // ACQUIRED indicates that the buffer has been acquired by the 470 // consumer. As with QUEUED, the contents must not be accessed 471 // by the consumer until the fence is signaled. 472 // 473 // The slot is "owned" by the consumer. It transitions to FREE 474 // when releaseBuffer is called. 475 ACQUIRED = 3 476 }; 477 478 // mBufferState is the current state of this buffer slot. 479 BufferState mBufferState; 480 481 // mRequestBufferCalled is used for validating that the producer did 482 // call requestBuffer() when told to do so. Technically this is not 483 // needed but useful for debugging and catching producer bugs. 484 bool mRequestBufferCalled; 485 486 // mFrameNumber is the number of the queued frame for this slot. This 487 // is used to dequeue buffers in LRU order (useful because buffers 488 // may be released before their release fence is signaled). 489 uint64_t mFrameNumber; 490 491 // mEglFence is the EGL sync object that must signal before the buffer 492 // associated with this buffer slot may be dequeued. It is initialized 493 // to EGL_NO_SYNC_KHR when the buffer is created and may be set to a 494 // new sync object in releaseBuffer. (This is deprecated in favor of 495 // mFence, below.) 496 EGLSyncKHR mEglFence; 497 498 // mFence is a fence which will signal when work initiated by the 499 // previous owner of the buffer is finished. When the buffer is FREE, 500 // the fence indicates when the consumer has finished reading 501 // from the buffer, or when the producer has finished writing if it 502 // called cancelBuffer after queueing some writes. When the buffer is 503 // QUEUED, it indicates when the producer has finished filling the 504 // buffer. When the buffer is DEQUEUED or ACQUIRED, the fence has been 505 // passed to the consumer or producer along with ownership of the 506 // buffer, and mFence is set to NO_FENCE. 507 sp<Fence> mFence; 508 509 // Indicates whether this buffer has been seen by a consumer yet 510 bool mAcquireCalled; 511 512 // Indicates whether this buffer needs to be cleaned up by the 513 // consumer. This is set when a buffer in ACQUIRED state is freed. 514 // It causes releaseBuffer to return STALE_BUFFER_SLOT. 515 bool mNeedsCleanupOnRelease; 516 }; 517 518 // mSlots is the array of buffer slots that must be mirrored on the 519 // producer side. This allows buffer ownership to be transferred between 520 // the producer and consumer without sending a GraphicBuffer over binder. 521 // The entire array is initialized to NULL at construction time, and 522 // buffers are allocated for a slot when requestBuffer is called with 523 // that slot's index. 524 BufferSlot mSlots[NUM_BUFFER_SLOTS]; 525 526 // mDefaultWidth holds the default width of allocated buffers. It is used 527 // in dequeueBuffer() if a width and height of zero is specified. 528 uint32_t mDefaultWidth; 529 530 // mDefaultHeight holds the default height of allocated buffers. It is used 531 // in dequeueBuffer() if a width and height of zero is specified. 532 uint32_t mDefaultHeight; 533 534 // mMaxAcquiredBufferCount is the number of buffers that the consumer may 535 // acquire at one time. It defaults to 1 and can be changed by the 536 // consumer via the setMaxAcquiredBufferCount method, but this may only be 537 // done when no producer is connected to the BufferQueue. 538 // 539 // This value is used to derive the value returned for the 540 // MIN_UNDEQUEUED_BUFFERS query by the producer. 541 int mMaxAcquiredBufferCount; 542 543 // mDefaultMaxBufferCount is the default limit on the number of buffers 544 // that will be allocated at one time. This default limit is set by the 545 // consumer. The limit (as opposed to the default limit) may be 546 // overridden by the producer. 547 int mDefaultMaxBufferCount; 548 549 // mOverrideMaxBufferCount is the limit on the number of buffers that will 550 // be allocated at one time. This value is set by the image producer by 551 // calling setBufferCount. The default is zero, which means the producer 552 // doesn't care about the number of buffers in the pool. In that case 553 // mDefaultMaxBufferCount is used as the limit. 554 int mOverrideMaxBufferCount; 555 556 // mGraphicBufferAlloc is the connection to SurfaceFlinger that is used to 557 // allocate new GraphicBuffer objects. 558 sp<IGraphicBufferAlloc> mGraphicBufferAlloc; 559 560 // mConsumerListener is used to notify the connected consumer of 561 // asynchronous events that it may wish to react to. It is initially set 562 // to NULL and is written by consumerConnect and consumerDisconnect. 563 sp<ConsumerListener> mConsumerListener; 564 565 // mConsumerControlledByApp whether the connected consumer is controlled by the 566 // application. 567 bool mConsumerControlledByApp; 568 569 // mDequeueBufferCannotBlock whether dequeueBuffer() isn't allowed to block. 570 // this flag is set during connect() when both consumer and producer are controlled 571 // by the application. 572 bool mDequeueBufferCannotBlock; 573 574 // mUseAsyncBuffer whether an extra buffer is used in async mode to prevent 575 // dequeueBuffer() from ever blocking. 576 bool mUseAsyncBuffer; 577 578 // mConnectedApi indicates the producer API that is currently connected 579 // to this BufferQueue. It defaults to NO_CONNECTED_API (= 0), and gets 580 // updated by the connect and disconnect methods. 581 int mConnectedApi; 582 583 // mDequeueCondition condition used for dequeueBuffer in synchronous mode 584 mutable Condition mDequeueCondition; 585 586 // mQueue is a FIFO of queued buffers used in synchronous mode 587 typedef Vector<BufferItem> Fifo; 588 Fifo mQueue; 589 590 // mAbandoned indicates that the BufferQueue will no longer be used to 591 // consume image buffers pushed to it using the IGraphicBufferProducer 592 // interface. It is initialized to false, and set to true in the 593 // consumerDisconnect method. A BufferQueue that has been abandoned will 594 // return the NO_INIT error from all IGraphicBufferProducer methods 595 // capable of returning an error. 596 bool mAbandoned; 597 598 // mConsumerName is a string used to identify the BufferQueue in log 599 // messages. It is set by the setConsumerName method. 600 String8 mConsumerName; 601 602 // mMutex is the mutex used to prevent concurrent access to the member 603 // variables of BufferQueue objects. It must be locked whenever the 604 // member variables are accessed. 605 mutable Mutex mMutex; 606 607 // mFrameCounter is the free running counter, incremented on every 608 // successful queueBuffer call, and buffer allocation. 609 uint64_t mFrameCounter; 610 611 // mBufferHasBeenQueued is true once a buffer has been queued. It is 612 // reset when something causes all buffers to be freed (e.g. changing the 613 // buffer count). 614 bool mBufferHasBeenQueued; 615 616 // mDefaultBufferFormat can be set so it will override 617 // the buffer format when it isn't specified in dequeueBuffer 618 uint32_t mDefaultBufferFormat; 619 620 // mConsumerUsageBits contains flags the consumer wants for GraphicBuffers 621 uint32_t mConsumerUsageBits; 622 623 // mTransformHint is used to optimize for screen rotations 624 uint32_t mTransformHint; 625}; 626 627// ---------------------------------------------------------------------------- 628}; // namespace android 629 630#endif // ANDROID_GUI_BUFFERQUEUE_H 631