BufferQueue.h revision fa5b40ebb8923133df12dc70591bfe35b3f1c9b3
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 22#include <gui/IGraphicBufferAlloc.h> 23#include <gui/ISurfaceTexture.h> 24 25#include <ui/GraphicBuffer.h> 26 27#include <utils/String8.h> 28#include <utils/Vector.h> 29#include <utils/threads.h> 30 31namespace android { 32// ---------------------------------------------------------------------------- 33 34class BufferQueue : public BnSurfaceTexture { 35public: 36 enum { MIN_UNDEQUEUED_BUFFERS = 2 }; 37 enum { 38 MIN_ASYNC_BUFFER_SLOTS = MIN_UNDEQUEUED_BUFFERS + 1, 39 MIN_SYNC_BUFFER_SLOTS = MIN_UNDEQUEUED_BUFFERS 40 }; 41 enum { NUM_BUFFER_SLOTS = 32 }; 42 enum { NO_CONNECTED_API = 0 }; 43 enum { INVALID_BUFFER_SLOT = -1 }; 44 45 // ConsumerListener is the interface through which the BufferQueue notifies 46 // the consumer of events that the consumer may wish to react to. Because 47 // the consumer will generally have a mutex that is locked during calls from 48 // teh consumer to the BufferQueue, these calls from the BufferQueue to the 49 // consumer *MUST* be called only when the BufferQueue mutex is NOT locked. 50 struct ConsumerListener : public virtual RefBase { 51 // onFrameAvailable is called from queueBuffer each time an additional 52 // frame becomes available for consumption. This means that frames that 53 // are queued while in asynchronous mode only trigger the callback if no 54 // previous frames are pending. Frames queued while in synchronous mode 55 // always trigger the callback. 56 // 57 // This is called without any lock held and can be called concurrently 58 // by multiple threads. 59 virtual void onFrameAvailable() = 0; 60 61 // onBuffersReleased is called to notify the buffer consumer that the 62 // BufferQueue has released its references to one or more GraphicBuffers 63 // contained in its slots. The buffer consumer should then call 64 // BufferQueue::getReleasedBuffers to retrieve the list of buffers 65 // 66 // This is called without any lock held and can be called concurrently 67 // by multiple threads. 68 virtual void onBuffersReleased() = 0; 69 }; 70 71 // ProxyConsumerListener is a ConsumerListener implementation that keeps a weak 72 // reference to the actual consumer object. It forwards all calls to that 73 // consumer object so long as it exists. 74 // 75 // This class exists to avoid having a circular reference between the 76 // BufferQueue object and the consumer object. The reason this can't be a weak 77 // reference in the BufferQueue class is because we're planning to expose the 78 // consumer side of a BufferQueue as a binder interface, which doesn't support 79 // weak references. 80 class ProxyConsumerListener : public BufferQueue::ConsumerListener { 81 public: 82 83 ProxyConsumerListener(const wp<BufferQueue::ConsumerListener>& consumerListener); 84 virtual ~ProxyConsumerListener(); 85 virtual void onFrameAvailable(); 86 virtual void onBuffersReleased(); 87 88 private: 89 90 // mConsumerListener is a weak reference to the ConsumerListener. This is 91 // the raison d'etre of ProxyConsumerListener. 92 wp<BufferQueue::ConsumerListener> mConsumerListener; 93 }; 94 95 96 // BufferQueue manages a pool of gralloc memory slots to be used 97 // by producers and consumers. 98 // allowSynchronousMode specifies whether or not synchronous mode can be 99 // enabled. 100 BufferQueue(bool allowSynchronousMode = true); 101 virtual ~BufferQueue(); 102 103 virtual int query(int what, int* value); 104 105 // setBufferCount updates the number of available buffer slots. After 106 // calling this all buffer slots are both unallocated and owned by the 107 // BufferQueue object (i.e. they are not owned by the client). 108 virtual status_t setBufferCount(int bufferCount); 109 110 virtual status_t requestBuffer(int slot, sp<GraphicBuffer>* buf); 111 112 // dequeueBuffer gets the next buffer slot index for the client to use. If a 113 // buffer slot is available then that slot index is written to the location 114 // pointed to by the buf argument and a status of OK is returned. If no 115 // slot is available then a status of -EBUSY is returned and buf is 116 // unmodified. 117 // The width and height parameters must be no greater than the minimum of 118 // GL_MAX_VIEWPORT_DIMS and GL_MAX_TEXTURE_SIZE (see: glGetIntegerv). 119 // An error due to invalid dimensions might not be reported until 120 // updateTexImage() is called. 121 virtual status_t dequeueBuffer(int *buf, uint32_t width, uint32_t height, 122 uint32_t format, uint32_t usage); 123 124 // queueBuffer returns a filled buffer to the BufferQueue. In addition, a 125 // timestamp must be provided for the buffer. The timestamp is in 126 // nanoseconds, and must be monotonically increasing. Its other semantics 127 // (zero point, etc) are client-dependent and should be documented by the 128 // client. 129 virtual status_t queueBuffer(int buf, int64_t timestamp, 130 uint32_t* outWidth, uint32_t* outHeight, uint32_t* outTransform); 131 virtual void cancelBuffer(int buf); 132 virtual status_t setCrop(const Rect& reg); 133 virtual status_t setTransform(uint32_t transform); 134 virtual status_t setScalingMode(int mode); 135 136 // setSynchronousMode set whether dequeueBuffer is synchronous or 137 // asynchronous. In synchronous mode, dequeueBuffer blocks until 138 // a buffer is available, the currently bound buffer can be dequeued and 139 // queued buffers will be retired in order. 140 // The default mode is asynchronous. 141 virtual status_t setSynchronousMode(bool enabled); 142 143 // connect attempts to connect a producer client API to the BufferQueue. 144 // This must be called before any other ISurfaceTexture methods are called 145 // except for getAllocator. 146 // 147 // This method will fail if the connect was previously called on the 148 // BufferQueue and no corresponding disconnect call was made. 149 virtual status_t connect(int api, 150 uint32_t* outWidth, uint32_t* outHeight, uint32_t* outTransform); 151 152 // disconnect attempts to disconnect a producer client API from the 153 // BufferQueue. Calling this method will cause any subsequent calls to other 154 // ISurfaceTexture methods to fail except for getAllocator and connect. 155 // Successfully calling connect after this will allow the other methods to 156 // succeed again. 157 // 158 // This method will fail if the the BufferQueue is not currently 159 // connected to the specified client API. 160 virtual status_t disconnect(int api); 161 162 // dump our state in a String 163 virtual void dump(String8& result) const; 164 virtual void dump(String8& result, const char* prefix, char* buffer, size_t SIZE) const; 165 166 // public facing structure for BufferSlot 167 struct BufferItem { 168 169 BufferItem() 170 : 171 mTransform(0), 172 mScalingMode(NATIVE_WINDOW_SCALING_MODE_FREEZE), 173 mTimestamp(0), 174 mFrameNumber(0), 175 mBuf(INVALID_BUFFER_SLOT) { 176 mCrop.makeInvalid(); 177 } 178 // mGraphicBuffer points to the buffer allocated for this slot or is NULL 179 // if no buffer has been allocated. 180 sp<GraphicBuffer> mGraphicBuffer; 181 182 // mCrop is the current crop rectangle for this buffer slot. This gets 183 // set to mNextCrop each time queueBuffer gets called for this buffer. 184 Rect mCrop; 185 186 // mTransform is the current transform flags for this buffer slot. This 187 // gets set to mNextTransform each time queueBuffer gets called for this 188 // slot. 189 uint32_t mTransform; 190 191 // mScalingMode is the current scaling mode for this buffer slot. This 192 // gets set to mNextScalingMode each time queueBuffer gets called for 193 // this slot. 194 uint32_t mScalingMode; 195 196 // mTimestamp is the current timestamp for this buffer slot. This gets 197 // to set by queueBuffer each time this slot is queued. 198 int64_t mTimestamp; 199 200 // mFrameNumber is the number of the queued frame for this slot. 201 uint64_t mFrameNumber; 202 203 // buf is the slot index of this buffer 204 int mBuf; 205 206 }; 207 208 // The following public functions is the consumer facing interface 209 210 // acquireBuffer attempts to acquire ownership of the next pending buffer in 211 // the BufferQueue. If no buffer is pending then it returns -EINVAL. If a 212 // buffer is successfully acquired, the information about the buffer is 213 // returned in BufferItem. If the buffer returned had previously been 214 // acquired then the BufferItem::mGraphicBuffer field of buffer is set to 215 // NULL and it is assumed that the consumer still holds a reference to the 216 // buffer. 217 status_t acquireBuffer(BufferItem *buffer); 218 219 // releaseBuffer releases a buffer slot from the consumer back to the 220 // BufferQueue pending a fence sync. 221 // 222 // Note that the dependencies on EGL will be removed once we switch to using 223 // the Android HW Sync HAL. 224 status_t releaseBuffer(int buf, EGLDisplay display, EGLSyncKHR fence); 225 226 // consumerConnect connects a consumer to the BufferQueue. Only one 227 // consumer may be connected, and when that consumer disconnects the 228 // BufferQueue is placed into the "abandoned" state, causing most 229 // interactions with the BufferQueue by the producer to fail. 230 status_t consumerConnect(const sp<ConsumerListener>& consumer); 231 232 // consumerDisconnect disconnects a consumer from the BufferQueue. All 233 // buffers will be freed and the BufferQueue is placed in the "abandoned" 234 // state, causing most interactions with the BufferQueue by the producer to 235 // fail. 236 status_t consumerDisconnect(); 237 238 // getReleasedBuffers sets the value pointed to by slotMask to a bit mask 239 // indicating which buffer slots the have been released by the BufferQueue 240 // but have not yet been released by the consumer. 241 status_t getReleasedBuffers(uint32_t* slotMask); 242 243 // setDefaultBufferSize is used to set the size of buffers returned by 244 // requestBuffers when a with and height of zero is requested. 245 status_t setDefaultBufferSize(uint32_t w, uint32_t h); 246 247 // setBufferCountServer set the buffer count. If the client has requested 248 // a buffer count using setBufferCount, the server-buffer count will 249 // take effect once the client sets the count back to zero. 250 status_t setBufferCountServer(int bufferCount); 251 252 // isSynchronousMode returns whether the SurfaceTexture is currently in 253 // synchronous mode. 254 bool isSynchronousMode() const; 255 256 // setConsumerName sets the name used in logging 257 void setConsumerName(const String8& name); 258 259 // setDefaultBufferFormat allows the BufferQueue to create 260 // GraphicBuffers of a defaultFormat if no format is specified 261 // in dequeueBuffer 262 status_t setDefaultBufferFormat(uint32_t defaultFormat); 263 264 // setConsumerUsageBits will turn on additional usage bits for dequeueBuffer 265 status_t setConsumerUsageBits(uint32_t usage); 266 267 // setTransformHint bakes in rotation to buffers so overlays can be used 268 status_t setTransformHint(uint32_t hint); 269 270private: 271 // freeBufferLocked frees the resources (both GraphicBuffer and EGLImage) 272 // for the given slot. 273 void freeBufferLocked(int index); 274 275 // freeAllBuffersLocked frees the resources (both GraphicBuffer and 276 // EGLImage) for all slots. 277 void freeAllBuffersLocked(); 278 279 // freeAllBuffersExceptHeadLocked frees the resources (both GraphicBuffer 280 // and EGLImage) for all slots except the head of mQueue 281 void freeAllBuffersExceptHeadLocked(); 282 283 // drainQueueLocked drains the buffer queue if we're in synchronous mode 284 // returns immediately otherwise. It returns NO_INIT if the BufferQueue 285 // became abandoned or disconnected during this call. 286 status_t drainQueueLocked(); 287 288 // drainQueueAndFreeBuffersLocked drains the buffer queue if we're in 289 // synchronous mode and free all buffers. In asynchronous mode, all buffers 290 // are freed except the current buffer. 291 status_t drainQueueAndFreeBuffersLocked(); 292 293 status_t setBufferCountServerLocked(int bufferCount); 294 295 struct BufferSlot { 296 297 BufferSlot() 298 : mEglDisplay(EGL_NO_DISPLAY), 299 mBufferState(BufferSlot::FREE), 300 mRequestBufferCalled(false), 301 mTransform(0), 302 mScalingMode(NATIVE_WINDOW_SCALING_MODE_FREEZE), 303 mTimestamp(0), 304 mFrameNumber(0), 305 mFence(EGL_NO_SYNC_KHR), 306 mAcquireCalled(false) { 307 mCrop.makeInvalid(); 308 } 309 310 // mGraphicBuffer points to the buffer allocated for this slot or is NULL 311 // if no buffer has been allocated. 312 sp<GraphicBuffer> mGraphicBuffer; 313 314 // mEglDisplay is the EGLDisplay used to create mEglImage. 315 EGLDisplay mEglDisplay; 316 317 // BufferState represents the different states in which a buffer slot 318 // can be. 319 enum BufferState { 320 // FREE indicates that the buffer is not currently being used and 321 // will not be used in the future until it gets dequeued and 322 // subsequently queued by the client. 323 // aka "owned by BufferQueue, ready to be dequeued" 324 FREE = 0, 325 326 // DEQUEUED indicates that the buffer has been dequeued by the 327 // client, but has not yet been queued or canceled. The buffer is 328 // considered 'owned' by the client, and the server should not use 329 // it for anything. 330 // 331 // Note that when in synchronous-mode (mSynchronousMode == true), 332 // the buffer that's currently attached to the texture may be 333 // dequeued by the client. That means that the current buffer can 334 // be in either the DEQUEUED or QUEUED state. In asynchronous mode, 335 // however, the current buffer is always in the QUEUED state. 336 // aka "owned by producer, ready to be queued" 337 DEQUEUED = 1, 338 339 // QUEUED indicates that the buffer has been queued by the client, 340 // and has not since been made available for the client to dequeue. 341 // Attaching the buffer to the texture does NOT transition the 342 // buffer away from the QUEUED state. However, in Synchronous mode 343 // the current buffer may be dequeued by the client under some 344 // circumstances. See the note about the current buffer in the 345 // documentation for DEQUEUED. 346 // aka "owned by BufferQueue, ready to be acquired" 347 QUEUED = 2, 348 349 // aka "owned by consumer, ready to be released" 350 ACQUIRED = 3 351 }; 352 353 // mBufferState is the current state of this buffer slot. 354 BufferState mBufferState; 355 356 // mRequestBufferCalled is used for validating that the client did 357 // call requestBuffer() when told to do so. Technically this is not 358 // needed but useful for debugging and catching client bugs. 359 bool mRequestBufferCalled; 360 361 // mCrop is the current crop rectangle for this buffer slot. This gets 362 // set to mNextCrop each time queueBuffer gets called for this buffer. 363 Rect mCrop; 364 365 // mTransform is the current transform flags for this buffer slot. This 366 // gets set to mNextTransform each time queueBuffer gets called for this 367 // slot. 368 uint32_t mTransform; 369 370 // mScalingMode is the current scaling mode for this buffer slot. This 371 // gets set to mNextScalingMode each time queueBuffer gets called for 372 // this slot. 373 uint32_t mScalingMode; 374 375 // mTimestamp is the current timestamp for this buffer slot. This gets 376 // to set by queueBuffer each time this slot is queued. 377 int64_t mTimestamp; 378 379 // mFrameNumber is the number of the queued frame for this slot. 380 uint64_t mFrameNumber; 381 382 // mFence is the EGL sync object that must signal before the buffer 383 // associated with this buffer slot may be dequeued. It is initialized 384 // to EGL_NO_SYNC_KHR when the buffer is created and (optionally, based 385 // on a compile-time option) set to a new sync object in updateTexImage. 386 EGLSyncKHR mFence; 387 388 // Indicates whether this buffer has been seen by a consumer yet 389 bool mAcquireCalled; 390 }; 391 392 // mSlots is the array of buffer slots that must be mirrored on the client 393 // side. This allows buffer ownership to be transferred between the client 394 // and server without sending a GraphicBuffer over binder. The entire array 395 // is initialized to NULL at construction time, and buffers are allocated 396 // for a slot when requestBuffer is called with that slot's index. 397 BufferSlot mSlots[NUM_BUFFER_SLOTS]; 398 399 // mDefaultWidth holds the default width of allocated buffers. It is used 400 // in requestBuffers() if a width and height of zero is specified. 401 uint32_t mDefaultWidth; 402 403 // mDefaultHeight holds the default height of allocated buffers. It is used 404 // in requestBuffers() if a width and height of zero is specified. 405 uint32_t mDefaultHeight; 406 407 // mPixelFormat holds the pixel format of allocated buffers. It is used 408 // in requestBuffers() if a format of zero is specified. 409 uint32_t mPixelFormat; 410 411 // mBufferCount is the number of buffer slots that the client and server 412 // must maintain. It defaults to MIN_ASYNC_BUFFER_SLOTS and can be changed 413 // by calling setBufferCount or setBufferCountServer 414 int mBufferCount; 415 416 // mClientBufferCount is the number of buffer slots requested by the client. 417 // The default is zero, which means the client doesn't care how many buffers 418 // there is. 419 int mClientBufferCount; 420 421 // mServerBufferCount buffer count requested by the server-side 422 int mServerBufferCount; 423 424 // mNextCrop is the crop rectangle that will be used for the next buffer 425 // that gets queued. It is set by calling setCrop. 426 Rect mNextCrop; 427 428 // mNextTransform is the transform identifier that will be used for the next 429 // buffer that gets queued. It is set by calling setTransform. 430 uint32_t mNextTransform; 431 432 // mNextScalingMode is the scaling mode that will be used for the next 433 // buffers that get queued. It is set by calling setScalingMode. 434 int mNextScalingMode; 435 436 // mGraphicBufferAlloc is the connection to SurfaceFlinger that is used to 437 // allocate new GraphicBuffer objects. 438 sp<IGraphicBufferAlloc> mGraphicBufferAlloc; 439 440 // mConsumerListener is used to notify the connected consumer of 441 // asynchronous events that it may wish to react to. It is initially set 442 // to NULL and is written by consumerConnect and consumerDisconnect. 443 sp<ConsumerListener> mConsumerListener; 444 445 // mSynchronousMode whether we're in synchronous mode or not 446 bool mSynchronousMode; 447 448 // mAllowSynchronousMode whether we allow synchronous mode or not 449 const bool mAllowSynchronousMode; 450 451 // mConnectedApi indicates the API that is currently connected to this 452 // BufferQueue. It defaults to NO_CONNECTED_API (= 0), and gets updated 453 // by the connect and disconnect methods. 454 int mConnectedApi; 455 456 // mDequeueCondition condition used for dequeueBuffer in synchronous mode 457 mutable Condition mDequeueCondition; 458 459 // mQueue is a FIFO of queued buffers used in synchronous mode 460 typedef Vector<int> Fifo; 461 Fifo mQueue; 462 463 // mAbandoned indicates that the BufferQueue will no longer be used to 464 // consume images buffers pushed to it using the ISurfaceTexture interface. 465 // It is initialized to false, and set to true in the abandon method. A 466 // BufferQueue that has been abandoned will return the NO_INIT error from 467 // all ISurfaceTexture methods capable of returning an error. 468 bool mAbandoned; 469 470 // mName is a string used to identify the BufferQueue in log messages. 471 // It is set by the setName method. 472 String8 mConsumerName; 473 474 // mMutex is the mutex used to prevent concurrent access to the member 475 // variables of BufferQueue objects. It must be locked whenever the 476 // member variables are accessed. 477 mutable Mutex mMutex; 478 479 // mFrameCounter is the free running counter, incremented for every buffer queued 480 // with the surface Texture. 481 uint64_t mFrameCounter; 482 483 // mBufferHasBeenQueued is true once a buffer has been queued. It is reset 484 // by changing the buffer count. 485 bool mBufferHasBeenQueued; 486 487 // mDefaultBufferFormat can be set so it will override 488 // the buffer format when it isn't specified in dequeueBuffer 489 uint32_t mDefaultBufferFormat; 490 491 // mConsumerUsageBits contains flags the consumer wants for GraphicBuffers 492 uint32_t mConsumerUsageBits; 493 494 // mTransformHint is used to optimize for screen rotations 495 uint32_t mTransformHint; 496}; 497 498// ---------------------------------------------------------------------------- 499}; // namespace android 500 501#endif // ANDROID_GUI_BUFFERQUEUE_H 502