BufferQueue.h revision e41b318bc4708e1dee9364e73215ff0d51fb76a1
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, int bufferCount = MIN_UNDEQUEUED_BUFFERS); 100 virtual ~BufferQueue(); 101 102 virtual int query(int what, int* value); 103 104 // setBufferCount updates the number of available buffer slots. After 105 // calling this all buffer slots are both unallocated and owned by the 106 // BufferQueue object (i.e. they are not owned by the client). 107 virtual status_t setBufferCount(int bufferCount); 108 109 virtual status_t requestBuffer(int slot, sp<GraphicBuffer>* buf); 110 111 // dequeueBuffer gets the next buffer slot index for the client to use. If a 112 // buffer slot is available then that slot index is written to the location 113 // pointed to by the buf argument and a status of OK is returned. If no 114 // slot is available then a status of -EBUSY is returned and buf is 115 // unmodified. 116 // The width and height parameters must be no greater than the minimum of 117 // GL_MAX_VIEWPORT_DIMS and GL_MAX_TEXTURE_SIZE (see: glGetIntegerv). 118 // An error due to invalid dimensions might not be reported until 119 // updateTexImage() is called. 120 virtual status_t dequeueBuffer(int *buf, uint32_t width, uint32_t height, 121 uint32_t format, uint32_t usage); 122 123 // queueBuffer returns a filled buffer to the BufferQueue. In addition, a 124 // timestamp must be provided for the buffer. The timestamp is in 125 // nanoseconds, and must be monotonically increasing. Its other semantics 126 // (zero point, etc) are client-dependent and should be documented by the 127 // client. 128 virtual status_t queueBuffer(int buf, 129 const QueueBufferInput& input, QueueBufferOutput* output); 130 131 virtual void cancelBuffer(int buf); 132 133 // setSynchronousMode set whether dequeueBuffer is synchronous or 134 // asynchronous. In synchronous mode, dequeueBuffer blocks until 135 // a buffer is available, the currently bound buffer can be dequeued and 136 // queued buffers will be retired in order. 137 // The default mode is asynchronous. 138 virtual status_t setSynchronousMode(bool enabled); 139 140 // connect attempts to connect a producer client API to the BufferQueue. 141 // This must be called before any other ISurfaceTexture methods are called 142 // except for getAllocator. 143 // 144 // This method will fail if the connect was previously called on the 145 // BufferQueue and no corresponding disconnect call was made. 146 virtual status_t connect(int api, QueueBufferOutput* output); 147 148 // disconnect attempts to disconnect a producer client API from the 149 // BufferQueue. Calling this method will cause any subsequent calls to other 150 // ISurfaceTexture methods to fail except for getAllocator and connect. 151 // Successfully calling connect after this will allow the other methods to 152 // succeed again. 153 // 154 // This method will fail if the the BufferQueue is not currently 155 // connected to the specified client API. 156 virtual status_t disconnect(int api); 157 158 // dump our state in a String 159 virtual void dump(String8& result) const; 160 virtual void dump(String8& result, const char* prefix, char* buffer, size_t SIZE) const; 161 162 // public facing structure for BufferSlot 163 struct BufferItem { 164 165 BufferItem() 166 : 167 mTransform(0), 168 mScalingMode(NATIVE_WINDOW_SCALING_MODE_FREEZE), 169 mTimestamp(0), 170 mFrameNumber(0), 171 mBuf(INVALID_BUFFER_SLOT) { 172 mCrop.makeInvalid(); 173 } 174 // mGraphicBuffer points to the buffer allocated for this slot or is NULL 175 // if no buffer has been allocated. 176 sp<GraphicBuffer> mGraphicBuffer; 177 178 // mCrop is the current crop rectangle for this buffer slot. 179 Rect mCrop; 180 181 // mTransform is the current transform flags for this buffer slot. 182 uint32_t mTransform; 183 184 // mScalingMode is the current scaling mode for this buffer slot. 185 uint32_t mScalingMode; 186 187 // mTimestamp is the current timestamp for this buffer slot. This gets 188 // to set by queueBuffer each time this slot is queued. 189 int64_t mTimestamp; 190 191 // mFrameNumber is the number of the queued frame for this slot. 192 uint64_t mFrameNumber; 193 194 // mBuf is the slot index of this buffer 195 int mBuf; 196 }; 197 198 // The following public functions is the consumer facing interface 199 200 // acquireBuffer attempts to acquire ownership of the next pending buffer in 201 // the BufferQueue. If no buffer is pending then it returns -EINVAL. If a 202 // buffer is successfully acquired, the information about the buffer is 203 // returned in BufferItem. If the buffer returned had previously been 204 // acquired then the BufferItem::mGraphicBuffer field of buffer is set to 205 // NULL and it is assumed that the consumer still holds a reference to the 206 // buffer. 207 status_t acquireBuffer(BufferItem *buffer); 208 209 // releaseBuffer releases a buffer slot from the consumer back to the 210 // BufferQueue pending a fence sync. 211 // 212 // If releaseBuffer returns STALE_BUFFER_SLOT, then the consumer must free 213 // any references to the just-released buffer that it might have, as if it 214 // had received a onBuffersReleased() call with a mask set for the released 215 // buffer. 216 // 217 // Note that the dependencies on EGL will be removed once we switch to using 218 // the Android HW Sync HAL. 219 status_t releaseBuffer(int buf, EGLDisplay display, EGLSyncKHR fence); 220 221 // consumerConnect connects a consumer to the BufferQueue. Only one 222 // consumer may be connected, and when that consumer disconnects the 223 // BufferQueue is placed into the "abandoned" state, causing most 224 // interactions with the BufferQueue by the producer to fail. 225 status_t consumerConnect(const sp<ConsumerListener>& consumer); 226 227 // consumerDisconnect disconnects a consumer from the BufferQueue. All 228 // buffers will be freed and the BufferQueue is placed in the "abandoned" 229 // state, causing most interactions with the BufferQueue by the producer to 230 // fail. 231 status_t consumerDisconnect(); 232 233 // getReleasedBuffers sets the value pointed to by slotMask to a bit mask 234 // indicating which buffer slots the have been released by the BufferQueue 235 // but have not yet been released by the consumer. 236 status_t getReleasedBuffers(uint32_t* slotMask); 237 238 // setDefaultBufferSize is used to set the size of buffers returned by 239 // requestBuffers when a with and height of zero is requested. 240 status_t setDefaultBufferSize(uint32_t w, uint32_t h); 241 242 // setBufferCountServer set the buffer count. If the client has requested 243 // a buffer count using setBufferCount, the server-buffer count will 244 // take effect once the client sets the count back to zero. 245 status_t setBufferCountServer(int bufferCount); 246 247 // isSynchronousMode returns whether the SurfaceTexture is currently in 248 // synchronous mode. 249 bool isSynchronousMode() const; 250 251 // setConsumerName sets the name used in logging 252 void setConsumerName(const String8& name); 253 254 // setDefaultBufferFormat allows the BufferQueue to create 255 // GraphicBuffers of a defaultFormat if no format is specified 256 // in dequeueBuffer 257 status_t setDefaultBufferFormat(uint32_t defaultFormat); 258 259 // setConsumerUsageBits will turn on additional usage bits for dequeueBuffer 260 status_t setConsumerUsageBits(uint32_t usage); 261 262 // setTransformHint bakes in rotation to buffers so overlays can be used 263 status_t setTransformHint(uint32_t hint); 264 265private: 266 // freeBufferLocked frees the resources (both GraphicBuffer and EGLImage) 267 // for the given slot. 268 void freeBufferLocked(int index); 269 270 // freeAllBuffersLocked frees the resources (both GraphicBuffer and 271 // EGLImage) for all slots. 272 void freeAllBuffersLocked(); 273 274 // freeAllBuffersExceptHeadLocked frees the resources (both GraphicBuffer 275 // and EGLImage) for all slots except the head of mQueue 276 void freeAllBuffersExceptHeadLocked(); 277 278 // drainQueueLocked drains the buffer queue if we're in synchronous mode 279 // returns immediately otherwise. It returns NO_INIT if the BufferQueue 280 // became abandoned or disconnected during this call. 281 status_t drainQueueLocked(); 282 283 // drainQueueAndFreeBuffersLocked drains the buffer queue if we're in 284 // synchronous mode and free all buffers. In asynchronous mode, all buffers 285 // are freed except the current buffer. 286 status_t drainQueueAndFreeBuffersLocked(); 287 288 status_t setBufferCountServerLocked(int bufferCount); 289 290 struct BufferSlot { 291 292 BufferSlot() 293 : mEglDisplay(EGL_NO_DISPLAY), 294 mBufferState(BufferSlot::FREE), 295 mRequestBufferCalled(false), 296 mTransform(0), 297 mScalingMode(NATIVE_WINDOW_SCALING_MODE_FREEZE), 298 mTimestamp(0), 299 mFrameNumber(0), 300 mFence(EGL_NO_SYNC_KHR), 301 mAcquireCalled(false), 302 mNeedsCleanupOnRelease(false) { 303 mCrop.makeInvalid(); 304 } 305 306 // mGraphicBuffer points to the buffer allocated for this slot or is NULL 307 // if no buffer has been allocated. 308 sp<GraphicBuffer> mGraphicBuffer; 309 310 // mEglDisplay is the EGLDisplay used to create mEglImage. 311 EGLDisplay mEglDisplay; 312 313 // BufferState represents the different states in which a buffer slot 314 // can be. 315 enum BufferState { 316 // FREE indicates that the buffer is not currently being used and 317 // will not be used in the future until it gets dequeued and 318 // subsequently queued by the client. 319 // aka "owned by BufferQueue, ready to be dequeued" 320 FREE = 0, 321 322 // DEQUEUED indicates that the buffer has been dequeued by the 323 // client, but has not yet been queued or canceled. The buffer is 324 // considered 'owned' by the client, and the server should not use 325 // it for anything. 326 // 327 // Note that when in synchronous-mode (mSynchronousMode == true), 328 // the buffer that's currently attached to the texture may be 329 // dequeued by the client. That means that the current buffer can 330 // be in either the DEQUEUED or QUEUED state. In asynchronous mode, 331 // however, the current buffer is always in the QUEUED state. 332 // aka "owned by producer, ready to be queued" 333 DEQUEUED = 1, 334 335 // QUEUED indicates that the buffer has been queued by the client, 336 // and has not since been made available for the client to dequeue. 337 // Attaching the buffer to the texture does NOT transition the 338 // buffer away from the QUEUED state. However, in Synchronous mode 339 // the current buffer may be dequeued by the client under some 340 // circumstances. See the note about the current buffer in the 341 // documentation for DEQUEUED. 342 // aka "owned by BufferQueue, ready to be acquired" 343 QUEUED = 2, 344 345 // aka "owned by consumer, ready to be released" 346 ACQUIRED = 3 347 }; 348 349 // mBufferState is the current state of this buffer slot. 350 BufferState mBufferState; 351 352 // mRequestBufferCalled is used for validating that the client did 353 // call requestBuffer() when told to do so. Technically this is not 354 // needed but useful for debugging and catching client bugs. 355 bool mRequestBufferCalled; 356 357 // mCrop is the current crop rectangle for this buffer slot. 358 Rect mCrop; 359 360 // mTransform is the current transform flags for this buffer slot. 361 uint32_t mTransform; 362 363 // mScalingMode is the current scaling mode for this buffer slot. 364 uint32_t mScalingMode; 365 366 // mTimestamp is the current timestamp for this buffer slot. This gets 367 // to set by queueBuffer each time this slot is queued. 368 int64_t mTimestamp; 369 370 // mFrameNumber is the number of the queued frame for this slot. 371 uint64_t mFrameNumber; 372 373 // mFence is the EGL sync object that must signal before the buffer 374 // associated with this buffer slot may be dequeued. It is initialized 375 // to EGL_NO_SYNC_KHR when the buffer is created and (optionally, based 376 // on a compile-time option) set to a new sync object in updateTexImage. 377 EGLSyncKHR mFence; 378 379 // Indicates whether this buffer has been seen by a consumer yet 380 bool mAcquireCalled; 381 382 // Indicates whether this buffer needs to be cleaned up by consumer 383 bool mNeedsCleanupOnRelease; 384 }; 385 386 // mSlots is the array of buffer slots that must be mirrored on the client 387 // side. This allows buffer ownership to be transferred between the client 388 // and server without sending a GraphicBuffer over binder. The entire array 389 // is initialized to NULL at construction time, and buffers are allocated 390 // for a slot when requestBuffer is called with that slot's index. 391 BufferSlot mSlots[NUM_BUFFER_SLOTS]; 392 393 // mDefaultWidth holds the default width of allocated buffers. It is used 394 // in requestBuffers() if a width and height of zero is specified. 395 uint32_t mDefaultWidth; 396 397 // mDefaultHeight holds the default height of allocated buffers. It is used 398 // in requestBuffers() if a width and height of zero is specified. 399 uint32_t mDefaultHeight; 400 401 // mPixelFormat holds the pixel format of allocated buffers. It is used 402 // in requestBuffers() if a format of zero is specified. 403 uint32_t mPixelFormat; 404 405 // mMinUndequeuedBuffers is a constraint on the number of buffers 406 // not dequeued at any time 407 int mMinUndequeuedBuffers; 408 409 // mMinAsyncBufferSlots is a constraint on the minimum mBufferCount 410 // when this BufferQueue is in asynchronous mode 411 int mMinAsyncBufferSlots; 412 413 // mMinSyncBufferSlots is a constraint on the minimum mBufferCount 414 // when this BufferQueue is in synchronous mode 415 int mMinSyncBufferSlots; 416 417 // mBufferCount is the number of buffer slots that the client and server 418 // must maintain. It defaults to MIN_ASYNC_BUFFER_SLOTS and can be changed 419 // by calling setBufferCount or setBufferCountServer 420 int mBufferCount; 421 422 // mClientBufferCount is the number of buffer slots requested by the client. 423 // The default is zero, which means the client doesn't care how many buffers 424 // there is. 425 int mClientBufferCount; 426 427 // mServerBufferCount buffer count requested by the server-side 428 int mServerBufferCount; 429 430 // mGraphicBufferAlloc is the connection to SurfaceFlinger that is used to 431 // allocate new GraphicBuffer objects. 432 sp<IGraphicBufferAlloc> mGraphicBufferAlloc; 433 434 // mConsumerListener is used to notify the connected consumer of 435 // asynchronous events that it may wish to react to. It is initially set 436 // to NULL and is written by consumerConnect and consumerDisconnect. 437 sp<ConsumerListener> mConsumerListener; 438 439 // mSynchronousMode whether we're in synchronous mode or not 440 bool mSynchronousMode; 441 442 // mAllowSynchronousMode whether we allow synchronous mode or not 443 const bool mAllowSynchronousMode; 444 445 // mConnectedApi indicates the API that is currently connected to this 446 // BufferQueue. It defaults to NO_CONNECTED_API (= 0), and gets updated 447 // by the connect and disconnect methods. 448 int mConnectedApi; 449 450 // mDequeueCondition condition used for dequeueBuffer in synchronous mode 451 mutable Condition mDequeueCondition; 452 453 // mQueue is a FIFO of queued buffers used in synchronous mode 454 typedef Vector<int> Fifo; 455 Fifo mQueue; 456 457 // mAbandoned indicates that the BufferQueue will no longer be used to 458 // consume images buffers pushed to it using the ISurfaceTexture interface. 459 // It is initialized to false, and set to true in the abandon method. A 460 // BufferQueue that has been abandoned will return the NO_INIT error from 461 // all ISurfaceTexture methods capable of returning an error. 462 bool mAbandoned; 463 464 // mName is a string used to identify the BufferQueue in log messages. 465 // It is set by the setName method. 466 String8 mConsumerName; 467 468 // mMutex is the mutex used to prevent concurrent access to the member 469 // variables of BufferQueue objects. It must be locked whenever the 470 // member variables are accessed. 471 mutable Mutex mMutex; 472 473 // mFrameCounter is the free running counter, incremented for every buffer queued 474 // with the surface Texture. 475 uint64_t mFrameCounter; 476 477 // mBufferHasBeenQueued is true once a buffer has been queued. It is reset 478 // by changing the buffer count. 479 bool mBufferHasBeenQueued; 480 481 // mDefaultBufferFormat can be set so it will override 482 // the buffer format when it isn't specified in dequeueBuffer 483 uint32_t mDefaultBufferFormat; 484 485 // mConsumerUsageBits contains flags the consumer wants for GraphicBuffers 486 uint32_t mConsumerUsageBits; 487 488 // mTransformHint is used to optimize for screen rotations 489 uint32_t mTransformHint; 490}; 491 492// ---------------------------------------------------------------------------- 493}; // namespace android 494 495#endif // ANDROID_GUI_BUFFERQUEUE_H 496