BufferQueue.h revision 851ef8f1bfbb164d61b1528a529a464f0a60dbaf
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 { 39 MIN_ASYNC_BUFFER_SLOTS = MIN_UNDEQUEUED_BUFFERS + 1, 40 MIN_SYNC_BUFFER_SLOTS = MIN_UNDEQUEUED_BUFFERS 41 }; 42 enum { NUM_BUFFER_SLOTS = 32 }; 43 enum { NO_CONNECTED_API = 0 }; 44 enum { INVALID_BUFFER_SLOT = -1 }; 45 46 // ConsumerListener is the interface through which the BufferQueue notifies 47 // the consumer of events that the consumer may wish to react to. Because 48 // the consumer will generally have a mutex that is locked during calls from 49 // teh consumer to the BufferQueue, these calls from the BufferQueue to the 50 // consumer *MUST* be called only when the BufferQueue mutex is NOT locked. 51 struct ConsumerListener : public virtual RefBase { 52 // onFrameAvailable is called from queueBuffer each time an additional 53 // frame becomes available for consumption. This means that frames that 54 // are queued while in asynchronous mode only trigger the callback if no 55 // previous frames are pending. Frames queued while in synchronous mode 56 // always trigger the callback. 57 // 58 // This is called without any lock held and can be called concurrently 59 // by multiple threads. 60 virtual void onFrameAvailable() = 0; 61 62 // onBuffersReleased is called to notify the buffer consumer that the 63 // BufferQueue has released its references to one or more GraphicBuffers 64 // contained in its slots. The buffer consumer should then call 65 // BufferQueue::getReleasedBuffers to retrieve the list of buffers 66 // 67 // This is called without any lock held and can be called concurrently 68 // by multiple threads. 69 virtual void onBuffersReleased() = 0; 70 }; 71 72 // ProxyConsumerListener is a ConsumerListener implementation that keeps a weak 73 // reference to the actual consumer object. It forwards all calls to that 74 // consumer object so long as it exists. 75 // 76 // This class exists to avoid having a circular reference between the 77 // BufferQueue object and the consumer object. The reason this can't be a weak 78 // reference in the BufferQueue class is because we're planning to expose the 79 // consumer side of a BufferQueue as a binder interface, which doesn't support 80 // weak references. 81 class ProxyConsumerListener : public BufferQueue::ConsumerListener { 82 public: 83 84 ProxyConsumerListener(const wp<BufferQueue::ConsumerListener>& consumerListener); 85 virtual ~ProxyConsumerListener(); 86 virtual void onFrameAvailable(); 87 virtual void onBuffersReleased(); 88 89 private: 90 91 // mConsumerListener is a weak reference to the ConsumerListener. This is 92 // the raison d'etre of ProxyConsumerListener. 93 wp<BufferQueue::ConsumerListener> mConsumerListener; 94 }; 95 96 97 // BufferQueue manages a pool of gralloc memory slots to be used 98 // by producers and consumers. 99 // allowSynchronousMode specifies whether or not synchronous mode can be 100 // enabled. 101 BufferQueue(bool allowSynchronousMode = true); 102 virtual ~BufferQueue(); 103 104 virtual int query(int what, int* value); 105 106 // setBufferCount updates the number of available buffer slots. After 107 // calling this all buffer slots are both unallocated and owned by the 108 // BufferQueue object (i.e. they are not owned by the client). 109 virtual status_t setBufferCount(int bufferCount); 110 111 virtual status_t requestBuffer(int slot, sp<GraphicBuffer>* buf); 112 113 // dequeueBuffer gets the next buffer slot index for the client to use. If a 114 // buffer slot is available then that slot index is written to the location 115 // pointed to by the buf argument and a status of OK is returned. If no 116 // slot is available then a status of -EBUSY is returned and buf is 117 // unmodified. 118 // The width and height parameters must be no greater than the minimum of 119 // GL_MAX_VIEWPORT_DIMS and GL_MAX_TEXTURE_SIZE (see: glGetIntegerv). 120 // An error due to invalid dimensions might not be reported until 121 // updateTexImage() is called. 122 virtual status_t dequeueBuffer(int *buf, uint32_t width, uint32_t height, 123 uint32_t format, uint32_t usage); 124 125 // queueBuffer returns a filled buffer to the BufferQueue. In addition, a 126 // timestamp must be provided for the buffer. The timestamp is in 127 // nanoseconds, and must be monotonically increasing. Its other semantics 128 // (zero point, etc) are client-dependent and should be documented by the 129 // client. 130 virtual status_t queueBuffer(int buf, int64_t timestamp, 131 const Rect& crop, int scalingMode, uint32_t transform, 132 uint32_t* outWidth, uint32_t* outHeight, uint32_t* outTransform); 133 virtual void cancelBuffer(int buf); 134 135 // setSynchronousMode set whether dequeueBuffer is synchronous or 136 // asynchronous. In synchronous mode, dequeueBuffer blocks until 137 // a buffer is available, the currently bound buffer can be dequeued and 138 // queued buffers will be retired in order. 139 // The default mode is asynchronous. 140 virtual status_t setSynchronousMode(bool enabled); 141 142 // connect attempts to connect a producer client API to the BufferQueue. 143 // This must be called before any other ISurfaceTexture methods are called 144 // except for getAllocator. 145 // 146 // This method will fail if the connect was previously called on the 147 // BufferQueue and no corresponding disconnect call was made. 148 virtual status_t connect(int api, 149 uint32_t* outWidth, uint32_t* outHeight, uint32_t* outTransform); 150 151 // disconnect attempts to disconnect a producer client API from the 152 // BufferQueue. Calling this method will cause any subsequent calls to other 153 // ISurfaceTexture methods to fail except for getAllocator and connect. 154 // Successfully calling connect after this will allow the other methods to 155 // succeed again. 156 // 157 // This method will fail if the the BufferQueue is not currently 158 // connected to the specified client API. 159 virtual status_t disconnect(int api); 160 161 // dump our state in a String 162 virtual void dump(String8& result) const; 163 virtual void dump(String8& result, const char* prefix, char* buffer, size_t SIZE) const; 164 165 // public facing structure for BufferSlot 166 struct BufferItem { 167 168 BufferItem() 169 : 170 mTransform(0), 171 mScalingMode(NATIVE_WINDOW_SCALING_MODE_FREEZE), 172 mTimestamp(0), 173 mFrameNumber(0), 174 mBuf(INVALID_BUFFER_SLOT) { 175 mCrop.makeInvalid(); 176 } 177 // mGraphicBuffer points to the buffer allocated for this slot or is NULL 178 // if no buffer has been allocated. 179 sp<GraphicBuffer> mGraphicBuffer; 180 181 // mCrop is the current crop rectangle for this buffer slot. 182 Rect mCrop; 183 184 // mTransform is the current transform flags for this buffer slot. 185 uint32_t mTransform; 186 187 // mScalingMode is the current scaling mode for this buffer slot. 188 uint32_t mScalingMode; 189 190 // mTimestamp is the current timestamp for this buffer slot. This gets 191 // to set by queueBuffer each time this slot is queued. 192 int64_t mTimestamp; 193 194 // mFrameNumber is the number of the queued frame for this slot. 195 uint64_t mFrameNumber; 196 197 // buf is the slot index of this buffer 198 int mBuf; 199 200 }; 201 202 // The following public functions is the consumer facing interface 203 204 // acquireBuffer attempts to acquire ownership of the next pending buffer in 205 // the BufferQueue. If no buffer is pending then it returns -EINVAL. If a 206 // buffer is successfully acquired, the information about the buffer is 207 // returned in BufferItem. If the buffer returned had previously been 208 // acquired then the BufferItem::mGraphicBuffer field of buffer is set to 209 // NULL and it is assumed that the consumer still holds a reference to the 210 // buffer. 211 status_t acquireBuffer(BufferItem *buffer); 212 213 // releaseBuffer releases a buffer slot from the consumer back to the 214 // BufferQueue pending a fence sync. 215 // 216 // Note that the dependencies on EGL will be removed once we switch to using 217 // the Android HW Sync HAL. 218 status_t releaseBuffer(int buf, EGLDisplay display, EGLSyncKHR fence); 219 220 // consumerConnect connects a consumer to the BufferQueue. Only one 221 // consumer may be connected, and when that consumer disconnects the 222 // BufferQueue is placed into the "abandoned" state, causing most 223 // interactions with the BufferQueue by the producer to fail. 224 status_t consumerConnect(const sp<ConsumerListener>& consumer); 225 226 // consumerDisconnect disconnects a consumer from the BufferQueue. All 227 // buffers will be freed and the BufferQueue is placed in the "abandoned" 228 // state, causing most interactions with the BufferQueue by the producer to 229 // fail. 230 status_t consumerDisconnect(); 231 232 // getReleasedBuffers sets the value pointed to by slotMask to a bit mask 233 // indicating which buffer slots the have been released by the BufferQueue 234 // but have not yet been released by the consumer. 235 status_t getReleasedBuffers(uint32_t* slotMask); 236 237 // setDefaultBufferSize is used to set the size of buffers returned by 238 // requestBuffers when a with and height of zero is requested. 239 status_t setDefaultBufferSize(uint32_t w, uint32_t h); 240 241 // setBufferCountServer set the buffer count. If the client has requested 242 // a buffer count using setBufferCount, the server-buffer count will 243 // take effect once the client sets the count back to zero. 244 status_t setBufferCountServer(int bufferCount); 245 246 // isSynchronousMode returns whether the SurfaceTexture is currently in 247 // synchronous mode. 248 bool isSynchronousMode() const; 249 250 // setConsumerName sets the name used in logging 251 void setConsumerName(const String8& name); 252 253 // setDefaultBufferFormat allows the BufferQueue to create 254 // GraphicBuffers of a defaultFormat if no format is specified 255 // in dequeueBuffer 256 status_t setDefaultBufferFormat(uint32_t defaultFormat); 257 258 // setConsumerUsageBits will turn on additional usage bits for dequeueBuffer 259 status_t setConsumerUsageBits(uint32_t usage); 260 261 // setTransformHint bakes in rotation to buffers so overlays can be used 262 status_t setTransformHint(uint32_t hint); 263 264private: 265 // freeBufferLocked frees the resources (both GraphicBuffer and EGLImage) 266 // for the given slot. 267 void freeBufferLocked(int index); 268 269 // freeAllBuffersLocked frees the resources (both GraphicBuffer and 270 // EGLImage) for all slots. 271 void freeAllBuffersLocked(); 272 273 // freeAllBuffersExceptHeadLocked frees the resources (both GraphicBuffer 274 // and EGLImage) for all slots except the head of mQueue 275 void freeAllBuffersExceptHeadLocked(); 276 277 // drainQueueLocked drains the buffer queue if we're in synchronous mode 278 // returns immediately otherwise. It returns NO_INIT if the BufferQueue 279 // became abandoned or disconnected during this call. 280 status_t drainQueueLocked(); 281 282 // drainQueueAndFreeBuffersLocked drains the buffer queue if we're in 283 // synchronous mode and free all buffers. In asynchronous mode, all buffers 284 // are freed except the current buffer. 285 status_t drainQueueAndFreeBuffersLocked(); 286 287 status_t setBufferCountServerLocked(int bufferCount); 288 289 struct BufferSlot { 290 291 BufferSlot() 292 : mEglDisplay(EGL_NO_DISPLAY), 293 mBufferState(BufferSlot::FREE), 294 mRequestBufferCalled(false), 295 mTransform(0), 296 mScalingMode(NATIVE_WINDOW_SCALING_MODE_FREEZE), 297 mTimestamp(0), 298 mFrameNumber(0), 299 mFence(EGL_NO_SYNC_KHR), 300 mAcquireCalled(false) { 301 mCrop.makeInvalid(); 302 } 303 304 // mGraphicBuffer points to the buffer allocated for this slot or is NULL 305 // if no buffer has been allocated. 306 sp<GraphicBuffer> mGraphicBuffer; 307 308 // mEglDisplay is the EGLDisplay used to create mEglImage. 309 EGLDisplay mEglDisplay; 310 311 // BufferState represents the different states in which a buffer slot 312 // can be. 313 enum BufferState { 314 // FREE indicates that the buffer is not currently being used and 315 // will not be used in the future until it gets dequeued and 316 // subsequently queued by the client. 317 // aka "owned by BufferQueue, ready to be dequeued" 318 FREE = 0, 319 320 // DEQUEUED indicates that the buffer has been dequeued by the 321 // client, but has not yet been queued or canceled. The buffer is 322 // considered 'owned' by the client, and the server should not use 323 // it for anything. 324 // 325 // Note that when in synchronous-mode (mSynchronousMode == true), 326 // the buffer that's currently attached to the texture may be 327 // dequeued by the client. That means that the current buffer can 328 // be in either the DEQUEUED or QUEUED state. In asynchronous mode, 329 // however, the current buffer is always in the QUEUED state. 330 // aka "owned by producer, ready to be queued" 331 DEQUEUED = 1, 332 333 // QUEUED indicates that the buffer has been queued by the client, 334 // and has not since been made available for the client to dequeue. 335 // Attaching the buffer to the texture does NOT transition the 336 // buffer away from the QUEUED state. However, in Synchronous mode 337 // the current buffer may be dequeued by the client under some 338 // circumstances. See the note about the current buffer in the 339 // documentation for DEQUEUED. 340 // aka "owned by BufferQueue, ready to be acquired" 341 QUEUED = 2, 342 343 // aka "owned by consumer, ready to be released" 344 ACQUIRED = 3 345 }; 346 347 // mBufferState is the current state of this buffer slot. 348 BufferState mBufferState; 349 350 // mRequestBufferCalled is used for validating that the client did 351 // call requestBuffer() when told to do so. Technically this is not 352 // needed but useful for debugging and catching client bugs. 353 bool mRequestBufferCalled; 354 355 // mCrop is the current crop rectangle for this buffer slot. 356 Rect mCrop; 357 358 // mTransform is the current transform flags for this buffer slot. 359 uint32_t mTransform; 360 361 // mScalingMode is the current scaling mode for this buffer slot. 362 uint32_t mScalingMode; 363 364 // mTimestamp is the current timestamp for this buffer slot. This gets 365 // to set by queueBuffer each time this slot is queued. 366 int64_t mTimestamp; 367 368 // mFrameNumber is the number of the queued frame for this slot. 369 uint64_t mFrameNumber; 370 371 // mFence is the EGL sync object that must signal before the buffer 372 // associated with this buffer slot may be dequeued. It is initialized 373 // to EGL_NO_SYNC_KHR when the buffer is created and (optionally, based 374 // on a compile-time option) set to a new sync object in updateTexImage. 375 EGLSyncKHR mFence; 376 377 // Indicates whether this buffer has been seen by a consumer yet 378 bool mAcquireCalled; 379 }; 380 381 // mSlots is the array of buffer slots that must be mirrored on the client 382 // side. This allows buffer ownership to be transferred between the client 383 // and server without sending a GraphicBuffer over binder. The entire array 384 // is initialized to NULL at construction time, and buffers are allocated 385 // for a slot when requestBuffer is called with that slot's index. 386 BufferSlot mSlots[NUM_BUFFER_SLOTS]; 387 388 // mDefaultWidth holds the default width of allocated buffers. It is used 389 // in requestBuffers() if a width and height of zero is specified. 390 uint32_t mDefaultWidth; 391 392 // mDefaultHeight holds the default height of allocated buffers. It is used 393 // in requestBuffers() if a width and height of zero is specified. 394 uint32_t mDefaultHeight; 395 396 // mPixelFormat holds the pixel format of allocated buffers. It is used 397 // in requestBuffers() if a format of zero is specified. 398 uint32_t mPixelFormat; 399 400 // mBufferCount is the number of buffer slots that the client and server 401 // must maintain. It defaults to MIN_ASYNC_BUFFER_SLOTS and can be changed 402 // by calling setBufferCount or setBufferCountServer 403 int mBufferCount; 404 405 // mClientBufferCount is the number of buffer slots requested by the client. 406 // The default is zero, which means the client doesn't care how many buffers 407 // there is. 408 int mClientBufferCount; 409 410 // mServerBufferCount buffer count requested by the server-side 411 int mServerBufferCount; 412 413 // mGraphicBufferAlloc is the connection to SurfaceFlinger that is used to 414 // allocate new GraphicBuffer objects. 415 sp<IGraphicBufferAlloc> mGraphicBufferAlloc; 416 417 // mConsumerListener is used to notify the connected consumer of 418 // asynchronous events that it may wish to react to. It is initially set 419 // to NULL and is written by consumerConnect and consumerDisconnect. 420 sp<ConsumerListener> mConsumerListener; 421 422 // mSynchronousMode whether we're in synchronous mode or not 423 bool mSynchronousMode; 424 425 // mAllowSynchronousMode whether we allow synchronous mode or not 426 const bool mAllowSynchronousMode; 427 428 // mConnectedApi indicates the API that is currently connected to this 429 // BufferQueue. It defaults to NO_CONNECTED_API (= 0), and gets updated 430 // by the connect and disconnect methods. 431 int mConnectedApi; 432 433 // mDequeueCondition condition used for dequeueBuffer in synchronous mode 434 mutable Condition mDequeueCondition; 435 436 // mQueue is a FIFO of queued buffers used in synchronous mode 437 typedef Vector<int> Fifo; 438 Fifo mQueue; 439 440 // mAbandoned indicates that the BufferQueue will no longer be used to 441 // consume images buffers pushed to it using the ISurfaceTexture interface. 442 // It is initialized to false, and set to true in the abandon method. A 443 // BufferQueue that has been abandoned will return the NO_INIT error from 444 // all ISurfaceTexture methods capable of returning an error. 445 bool mAbandoned; 446 447 // mName is a string used to identify the BufferQueue in log messages. 448 // It is set by the setName method. 449 String8 mConsumerName; 450 451 // mMutex is the mutex used to prevent concurrent access to the member 452 // variables of BufferQueue objects. It must be locked whenever the 453 // member variables are accessed. 454 mutable Mutex mMutex; 455 456 // mFrameCounter is the free running counter, incremented for every buffer queued 457 // with the surface Texture. 458 uint64_t mFrameCounter; 459 460 // mBufferHasBeenQueued is true once a buffer has been queued. It is reset 461 // by changing the buffer count. 462 bool mBufferHasBeenQueued; 463 464 // mDefaultBufferFormat can be set so it will override 465 // the buffer format when it isn't specified in dequeueBuffer 466 uint32_t mDefaultBufferFormat; 467 468 // mConsumerUsageBits contains flags the consumer wants for GraphicBuffers 469 uint32_t mConsumerUsageBits; 470 471 // mTransformHint is used to optimize for screen rotations 472 uint32_t mTransformHint; 473}; 474 475// ---------------------------------------------------------------------------- 476}; // namespace android 477 478#endif // ANDROID_GUI_BUFFERQUEUE_H 479