BufferQueue.h revision 1585c4d9fbbba3ba70ae625923b85cd02cb8a0fd
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. allowSynchronousMode specifies whether or not 101 // synchronous mode can be enabled by the producer. allocator is used to 102 // allocate all the needed gralloc buffers. 103 BufferQueue(bool allowSynchronousMode = true, 104 const sp<IGraphicBufferAlloc>& allocator = NULL); 105 virtual ~BufferQueue(); 106 107 // Query native window attributes. The "what" values are enumerated in 108 // window.h (e.g. NATIVE_WINDOW_FORMAT). 109 virtual int query(int what, int* value); 110 111 // setBufferCount updates the number of available buffer slots. If this 112 // method succeeds, buffer slots will be both unallocated and owned by 113 // the BufferQueue object (i.e. they are not owned by the producer or 114 // consumer). 115 // 116 // This will fail if the producer has dequeued any buffers, or if 117 // bufferCount is invalid. bufferCount must generally be a value 118 // between the minimum undequeued buffer count and NUM_BUFFER_SLOTS 119 // (inclusive). It may also be set to zero (the default) to indicate 120 // that the producer does not wish to set a value. The minimum value 121 // can be obtained by calling query(NATIVE_WINDOW_MIN_UNDEQUEUED_BUFFERS, 122 // ...). 123 // 124 // This may only be called by the producer. The consumer will be told 125 // to discard buffers through the onBuffersReleased callback. 126 virtual status_t setBufferCount(int bufferCount); 127 128 // requestBuffer returns the GraphicBuffer for slot N. 129 // 130 // In normal operation, this is called the first time slot N is returned 131 // by dequeueBuffer. It must be called again if dequeueBuffer returns 132 // flags indicating that previously-returned buffers are no longer valid. 133 virtual status_t requestBuffer(int slot, sp<GraphicBuffer>* buf); 134 135 // dequeueBuffer gets the next buffer slot index for the producer to use. 136 // If a buffer slot is available then that slot index is written to the 137 // location pointed to by the buf argument and a status of OK is returned. 138 // If no slot is available then a status of -EBUSY is returned and buf is 139 // unmodified. 140 // 141 // The fence parameter will be updated to hold the fence associated with 142 // the buffer. The contents of the buffer must not be overwritten until the 143 // fence signals. If the fence is Fence::NO_FENCE, the buffer may be 144 // written immediately. 145 // 146 // The width and height parameters must be no greater than the minimum of 147 // GL_MAX_VIEWPORT_DIMS and GL_MAX_TEXTURE_SIZE (see: glGetIntegerv). 148 // An error due to invalid dimensions might not be reported until 149 // updateTexImage() is called. If width and height are both zero, the 150 // default values specified by setDefaultBufferSize() are used instead. 151 // 152 // The pixel formats are enumerated in graphics.h, e.g. 153 // HAL_PIXEL_FORMAT_RGBA_8888. If the format is 0, the default format 154 // will be used. 155 // 156 // The usage argument specifies gralloc buffer usage flags. The values 157 // are enumerated in gralloc.h, e.g. GRALLOC_USAGE_HW_RENDER. These 158 // will be merged with the usage flags specified by setConsumerUsageBits. 159 // 160 // The return value may be a negative error value or a non-negative 161 // collection of flags. If the flags are set, the return values are 162 // valid, but additional actions must be performed. 163 // 164 // If IGraphicBufferProducer::BUFFER_NEEDS_REALLOCATION is set, the 165 // producer must discard cached GraphicBuffer references for the slot 166 // returned in buf. 167 // If IGraphicBufferProducer::RELEASE_ALL_BUFFERS is set, the producer 168 // must discard cached GraphicBuffer references for all slots. 169 // 170 // In both cases, the producer will need to call requestBuffer to get a 171 // GraphicBuffer handle for the returned slot. 172 virtual status_t dequeueBuffer(int *buf, sp<Fence>* fence, 173 uint32_t width, uint32_t height, uint32_t format, uint32_t usage); 174 175 // queueBuffer returns a filled buffer to the BufferQueue. 176 // 177 // Additional data is provided in the QueueBufferInput struct. Notably, 178 // a timestamp must be provided for the buffer. The timestamp is in 179 // nanoseconds, and must be monotonically increasing. Its other semantics 180 // (zero point, etc) are producer-specific and should be documented by the 181 // producer. 182 // 183 // The caller may provide a fence that signals when all rendering 184 // operations have completed. Alternatively, NO_FENCE may be used, 185 // indicating that the buffer is ready immediately. 186 // 187 // Some values are returned in the output struct: the current settings 188 // for default width and height, the current transform hint, and the 189 // number of queued buffers. 190 virtual status_t queueBuffer(int buf, 191 const QueueBufferInput& input, QueueBufferOutput* output); 192 193 // cancelBuffer returns a dequeued buffer to the BufferQueue, but doesn't 194 // queue it for use by the consumer. 195 // 196 // The buffer will not be overwritten until the fence signals. The fence 197 // will usually be the one obtained from dequeueBuffer. 198 virtual void cancelBuffer(int buf, const sp<Fence>& fence); 199 200 // setSynchronousMode sets whether dequeueBuffer is synchronous or 201 // asynchronous. In synchronous mode, dequeueBuffer blocks until 202 // a buffer is available, the currently bound buffer can be dequeued and 203 // queued buffers will be acquired in order. In asynchronous mode, 204 // a queued buffer may be replaced by a subsequently queued buffer. 205 // 206 // The default mode is asynchronous. 207 virtual status_t setSynchronousMode(bool enabled); 208 209 // connect attempts to connect a producer API to the BufferQueue. This 210 // must be called before any other IGraphicBufferProducer methods are 211 // called except for getAllocator. A consumer must already be connected. 212 // 213 // This method will fail if connect was previously called on the 214 // BufferQueue and no corresponding disconnect call was made (i.e. if 215 // it's still connected to a producer). 216 // 217 // APIs are enumerated in window.h (e.g. NATIVE_WINDOW_API_CPU). 218 virtual status_t connect(int api, QueueBufferOutput* output); 219 220 // disconnect attempts to disconnect a producer API from the BufferQueue. 221 // Calling this method will cause any subsequent calls to other 222 // IGraphicBufferProducer methods to fail except for getAllocator and connect. 223 // Successfully calling connect after this will allow the other methods to 224 // succeed again. 225 // 226 // This method will fail if the the BufferQueue is not currently 227 // connected to the specified producer API. 228 virtual status_t disconnect(int api); 229 230 // dump our state in a String 231 virtual void dump(String8& result) const; 232 virtual void dump(String8& result, const char* prefix) const; 233 234 // public facing structure for BufferSlot 235 struct BufferItem { 236 237 BufferItem() 238 : 239 mTransform(0), 240 mScalingMode(NATIVE_WINDOW_SCALING_MODE_FREEZE), 241 mTimestamp(0), 242 mFrameNumber(0), 243 mBuf(INVALID_BUFFER_SLOT), 244 mAcquireCalled(false) { 245 mCrop.makeInvalid(); 246 } 247 // mGraphicBuffer points to the buffer allocated for this slot, or is NULL 248 // if the buffer in this slot has been acquired in the past (see 249 // BufferSlot.mAcquireCalled). 250 sp<GraphicBuffer> mGraphicBuffer; 251 252 // mCrop is the current crop rectangle for this buffer slot. 253 Rect mCrop; 254 255 // mTransform is the current transform flags for this buffer slot. 256 uint32_t mTransform; 257 258 // mScalingMode is the current scaling mode for this buffer slot. 259 uint32_t mScalingMode; 260 261 // mTimestamp is the current timestamp for this buffer slot. This gets 262 // to set by queueBuffer each time this slot is queued. 263 int64_t mTimestamp; 264 265 // mFrameNumber is the number of the queued frame for this slot. 266 uint64_t mFrameNumber; 267 268 // mBuf is the slot index of this buffer 269 int mBuf; 270 271 // mFence is a fence that will signal when the buffer is idle. 272 sp<Fence> mFence; 273 274 // Indicates whether this buffer has been seen by a consumer yet 275 bool mAcquireCalled; 276 }; 277 278 // The following public functions are the consumer-facing interface 279 280 // acquireBuffer attempts to acquire ownership of the next pending buffer in 281 // the BufferQueue. If no buffer is pending then it returns -EINVAL. If a 282 // buffer is successfully acquired, the information about the buffer is 283 // returned in BufferItem. If the buffer returned had previously been 284 // acquired then the BufferItem::mGraphicBuffer field of buffer is set to 285 // NULL and it is assumed that the consumer still holds a reference to the 286 // buffer. 287 // 288 // If presentWhen is nonzero, it indicates the time when the buffer will 289 // be displayed on screen. If the buffer's timestamp is farther in the 290 // future, the buffer won't be acquired, and PRESENT_LATER will be 291 // returned. The presentation time is in nanoseconds, and the time base 292 // is CLOCK_MONOTONIC. 293 status_t acquireBuffer(BufferItem *buffer, nsecs_t presentWhen); 294 295 // releaseBuffer releases a buffer slot from the consumer back to the 296 // BufferQueue. This may be done while the buffer's contents are still 297 // being accessed. The fence will signal when the buffer is no longer 298 // in use. frameNumber is used to indentify the exact buffer returned. 299 // 300 // If releaseBuffer returns STALE_BUFFER_SLOT, then the consumer must free 301 // any references to the just-released buffer that it might have, as if it 302 // had received a onBuffersReleased() call with a mask set for the released 303 // buffer. 304 // 305 // Note that the dependencies on EGL will be removed once we switch to using 306 // the Android HW Sync HAL. 307 status_t releaseBuffer(int buf, uint64_t frameNumber, 308 EGLDisplay display, EGLSyncKHR fence, 309 const sp<Fence>& releaseFence); 310 311 // consumerConnect connects a consumer to the BufferQueue. Only one 312 // consumer may be connected, and when that consumer disconnects the 313 // BufferQueue is placed into the "abandoned" state, causing most 314 // interactions with the BufferQueue by the producer to fail. 315 // 316 // consumer may not be NULL. 317 status_t consumerConnect(const sp<ConsumerListener>& consumer); 318 319 // consumerDisconnect disconnects a consumer from the BufferQueue. All 320 // buffers will be freed and the BufferQueue is placed in the "abandoned" 321 // state, causing most interactions with the BufferQueue by the producer to 322 // fail. 323 status_t consumerDisconnect(); 324 325 // getReleasedBuffers sets the value pointed to by slotMask to a bit mask 326 // indicating which buffer slots have been released by the BufferQueue 327 // but have not yet been released by the consumer. 328 // 329 // This should be called from the onBuffersReleased() callback. 330 status_t getReleasedBuffers(uint32_t* slotMask); 331 332 // setDefaultBufferSize is used to set the size of buffers returned by 333 // dequeueBuffer when a width and height of zero is requested. Default 334 // is 1x1. 335 status_t setDefaultBufferSize(uint32_t w, uint32_t h); 336 337 // setDefaultMaxBufferCount sets the default value for the maximum buffer 338 // count (the initial default is 2). If the producer has requested a 339 // buffer count using setBufferCount, the default buffer count will only 340 // take effect if the producer sets the count back to zero. 341 // 342 // The count must be between 2 and NUM_BUFFER_SLOTS, inclusive. 343 status_t setDefaultMaxBufferCount(int bufferCount); 344 345 // setMaxAcquiredBufferCount sets the maximum number of buffers that can 346 // be acquired by the consumer at one time (default 1). This call will 347 // fail if a producer is connected to the BufferQueue. 348 status_t setMaxAcquiredBufferCount(int maxAcquiredBuffers); 349 350 // isSynchronousMode returns whether the BufferQueue is currently in 351 // synchronous mode. 352 bool isSynchronousMode() const; 353 354 // setConsumerName sets the name used in logging 355 void setConsumerName(const String8& name); 356 357 // setDefaultBufferFormat allows the BufferQueue to create 358 // GraphicBuffers of a defaultFormat if no format is specified 359 // in dequeueBuffer. Formats are enumerated in graphics.h; the 360 // initial default is HAL_PIXEL_FORMAT_RGBA_8888. 361 status_t setDefaultBufferFormat(uint32_t defaultFormat); 362 363 // setConsumerUsageBits will turn on additional usage bits for dequeueBuffer. 364 // These are merged with the bits passed to dequeueBuffer. The values are 365 // enumerated in gralloc.h, e.g. GRALLOC_USAGE_HW_RENDER; the default is 0. 366 status_t setConsumerUsageBits(uint32_t usage); 367 368 // setTransformHint bakes in rotation to buffers so overlays can be used. 369 // The values are enumerated in window.h, e.g. 370 // NATIVE_WINDOW_TRANSFORM_ROT_90. The default is 0 (no transform). 371 status_t setTransformHint(uint32_t hint); 372 373private: 374 // freeBufferLocked frees the GraphicBuffer and sync resources for the 375 // given slot. 376 void freeBufferLocked(int index); 377 378 // freeAllBuffersLocked frees the GraphicBuffer and sync resources for 379 // all slots. 380 void freeAllBuffersLocked(); 381 382 // drainQueueLocked waits for the buffer queue to empty if we're in 383 // synchronous mode, or returns immediately otherwise. It returns NO_INIT 384 // if the BufferQueue is abandoned (consumer disconnected) or disconnected 385 // (producer disconnected) during the call. 386 status_t drainQueueLocked(); 387 388 // drainQueueAndFreeBuffersLocked drains the buffer queue if we're in 389 // synchronous mode and free all buffers. In asynchronous mode, all buffers 390 // are freed except the currently queued buffer (if it exists). 391 status_t drainQueueAndFreeBuffersLocked(); 392 393 // setDefaultMaxBufferCountLocked sets the maximum number of buffer slots 394 // that will be used if the producer does not override the buffer slot 395 // count. The count must be between 2 and NUM_BUFFER_SLOTS, inclusive. 396 // The initial default is 2. 397 status_t setDefaultMaxBufferCountLocked(int count); 398 399 // getMinBufferCountLocked returns the minimum number of buffers allowed 400 // given the current BufferQueue state. 401 int getMinMaxBufferCountLocked() const; 402 403 // getMinUndequeuedBufferCountLocked returns the minimum number of buffers 404 // that must remain in a state other than DEQUEUED. 405 int getMinUndequeuedBufferCountLocked() const; 406 407 // getMaxBufferCountLocked returns the maximum number of buffers that can 408 // be allocated at once. This value depends upon the following member 409 // variables: 410 // 411 // mSynchronousMode 412 // mMaxAcquiredBufferCount 413 // mDefaultMaxBufferCount 414 // mOverrideMaxBufferCount 415 // 416 // Any time one of these member variables is changed while a producer is 417 // connected, mDequeueCondition must be broadcast. 418 int getMaxBufferCountLocked() const; 419 420 // stillTracking returns true iff the buffer item is still being tracked 421 // in one of the slots. 422 bool stillTracking(const BufferItem *item) const; 423 424 struct BufferSlot { 425 426 BufferSlot() 427 : mEglDisplay(EGL_NO_DISPLAY), 428 mBufferState(BufferSlot::FREE), 429 mRequestBufferCalled(false), 430 mFrameNumber(0), 431 mEglFence(EGL_NO_SYNC_KHR), 432 mAcquireCalled(false), 433 mNeedsCleanupOnRelease(false) { 434 } 435 436 // mGraphicBuffer points to the buffer allocated for this slot or is NULL 437 // if no buffer has been allocated. 438 sp<GraphicBuffer> mGraphicBuffer; 439 440 // mEglDisplay is the EGLDisplay used to create EGLSyncKHR objects. 441 EGLDisplay mEglDisplay; 442 443 // BufferState represents the different states in which a buffer slot 444 // can be. All slots are initially FREE. 445 enum BufferState { 446 // FREE indicates that the buffer is available to be dequeued 447 // by the producer. The buffer may be in use by the consumer for 448 // a finite time, so the buffer must not be modified until the 449 // associated fence is signaled. 450 // 451 // The slot is "owned" by BufferQueue. It transitions to DEQUEUED 452 // when dequeueBuffer is called. 453 FREE = 0, 454 455 // DEQUEUED indicates that the buffer has been dequeued by the 456 // producer, but has not yet been queued or canceled. The 457 // producer may modify the buffer's contents as soon as the 458 // associated ready fence is signaled. 459 // 460 // The slot is "owned" by the producer. It can transition to 461 // QUEUED (via queueBuffer) or back to FREE (via cancelBuffer). 462 DEQUEUED = 1, 463 464 // QUEUED indicates that the buffer has been filled by the 465 // producer and queued for use by the consumer. The buffer 466 // contents may continue to be modified for a finite time, so 467 // the contents must not be accessed until the associated fence 468 // is signaled. 469 // 470 // The slot is "owned" by BufferQueue. It can transition to 471 // ACQUIRED (via acquireBuffer) or to FREE (if another buffer is 472 // queued in asynchronous mode). 473 QUEUED = 2, 474 475 // ACQUIRED indicates that the buffer has been acquired by the 476 // consumer. As with QUEUED, the contents must not be accessed 477 // by the consumer until the fence is signaled. 478 // 479 // The slot is "owned" by the consumer. It transitions to FREE 480 // when releaseBuffer is called. 481 ACQUIRED = 3 482 }; 483 484 // mBufferState is the current state of this buffer slot. 485 BufferState mBufferState; 486 487 // mRequestBufferCalled is used for validating that the producer did 488 // call requestBuffer() when told to do so. Technically this is not 489 // needed but useful for debugging and catching producer bugs. 490 bool mRequestBufferCalled; 491 492 // mFrameNumber is the number of the queued frame for this slot. This 493 // is used to dequeue buffers in LRU order (useful because buffers 494 // may be released before their release fence is signaled). 495 uint64_t mFrameNumber; 496 497 // mEglFence is the EGL sync object that must signal before the buffer 498 // associated with this buffer slot may be dequeued. It is initialized 499 // to EGL_NO_SYNC_KHR when the buffer is created and may be set to a 500 // new sync object in releaseBuffer. (This is deprecated in favor of 501 // mFence, below.) 502 EGLSyncKHR mEglFence; 503 504 // mFence is a fence which will signal when work initiated by the 505 // previous owner of the buffer is finished. When the buffer is FREE, 506 // the fence indicates when the consumer has finished reading 507 // from the buffer, or when the producer has finished writing if it 508 // called cancelBuffer after queueing some writes. When the buffer is 509 // QUEUED, it indicates when the producer has finished filling the 510 // buffer. When the buffer is DEQUEUED or ACQUIRED, the fence has been 511 // passed to the consumer or producer along with ownership of the 512 // buffer, and mFence is set to NO_FENCE. 513 sp<Fence> mFence; 514 515 // Indicates whether this buffer has been seen by a consumer yet 516 bool mAcquireCalled; 517 518 // Indicates whether this buffer needs to be cleaned up by the 519 // consumer. This is set when a buffer in ACQUIRED state is freed. 520 // It causes releaseBuffer to return STALE_BUFFER_SLOT. 521 bool mNeedsCleanupOnRelease; 522 }; 523 524 // mSlots is the array of buffer slots that must be mirrored on the 525 // producer side. This allows buffer ownership to be transferred between 526 // the producer and consumer without sending a GraphicBuffer over binder. 527 // The entire array is initialized to NULL at construction time, and 528 // buffers are allocated for a slot when requestBuffer is called with 529 // that slot's index. 530 BufferSlot mSlots[NUM_BUFFER_SLOTS]; 531 532 // mDefaultWidth holds the default width of allocated buffers. It is used 533 // in dequeueBuffer() if a width and height of zero is specified. 534 uint32_t mDefaultWidth; 535 536 // mDefaultHeight holds the default height of allocated buffers. It is used 537 // in dequeueBuffer() if a width and height of zero is specified. 538 uint32_t mDefaultHeight; 539 540 // mMaxAcquiredBufferCount is the number of buffers that the consumer may 541 // acquire at one time. It defaults to 1 and can be changed by the 542 // consumer via the setMaxAcquiredBufferCount method, but this may only be 543 // done when no producer is connected to the BufferQueue. 544 // 545 // This value is used to derive the value returned for the 546 // MIN_UNDEQUEUED_BUFFERS query by the producer. 547 int mMaxAcquiredBufferCount; 548 549 // mDefaultMaxBufferCount is the default limit on the number of buffers 550 // that will be allocated at one time. This default limit is set by the 551 // consumer. The limit (as opposed to the default limit) may be 552 // overridden by the producer. 553 int mDefaultMaxBufferCount; 554 555 // mOverrideMaxBufferCount is the limit on the number of buffers that will 556 // be allocated at one time. This value is set by the image producer by 557 // calling setBufferCount. The default is zero, which means the producer 558 // doesn't care about the number of buffers in the pool. In that case 559 // mDefaultMaxBufferCount is used as the limit. 560 int mOverrideMaxBufferCount; 561 562 // mGraphicBufferAlloc is the connection to SurfaceFlinger that is used to 563 // allocate new GraphicBuffer objects. 564 sp<IGraphicBufferAlloc> mGraphicBufferAlloc; 565 566 // mConsumerListener is used to notify the connected consumer of 567 // asynchronous events that it may wish to react to. It is initially set 568 // to NULL and is written by consumerConnect and consumerDisconnect. 569 sp<ConsumerListener> mConsumerListener; 570 571 // mSynchronousMode whether we're in synchronous mode or not 572 bool mSynchronousMode; 573 574 // mAllowSynchronousMode whether we allow synchronous mode or not. Set 575 // when the BufferQueue is created (by the consumer). 576 const bool mAllowSynchronousMode; 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