| /* |
| * Copyright (C) 2007 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #define LOG_TAG "SharedBufferStack" |
| |
| #include <stdint.h> |
| #include <sys/types.h> |
| |
| #include <utils/Debug.h> |
| #include <utils/Log.h> |
| #include <utils/threads.h> |
| |
| #include <private/ui/SharedBufferStack.h> |
| |
| #include <ui/Rect.h> |
| #include <ui/Region.h> |
| |
| #define DEBUG_ATOMICS 0 |
| |
| namespace android { |
| // ---------------------------------------------------------------------------- |
| |
| SharedClient::SharedClient() |
| : lock(Mutex::SHARED) |
| { |
| } |
| |
| SharedClient::~SharedClient() { |
| } |
| |
| |
| // these functions are used by the clients |
| status_t SharedClient::validate(size_t i) const { |
| if (uint32_t(i) >= uint32_t(NUM_LAYERS_MAX)) |
| return BAD_INDEX; |
| return surfaces[i].status; |
| } |
| |
| uint32_t SharedClient::getIdentity(size_t token) const { |
| return uint32_t(surfaces[token].identity); |
| } |
| |
| // ---------------------------------------------------------------------------- |
| |
| |
| SharedBufferStack::SharedBufferStack() |
| { |
| } |
| |
| void SharedBufferStack::init(int32_t i) |
| { |
| inUse = -1; |
| status = NO_ERROR; |
| identity = i; |
| } |
| |
| status_t SharedBufferStack::setDirtyRegion(int buffer, const Region& dirty) |
| { |
| if (uint32_t(buffer) >= NUM_BUFFER_MAX) |
| return BAD_INDEX; |
| |
| // in the current implementation we only send a single rectangle |
| const Rect bounds(dirty.getBounds()); |
| FlatRegion& reg(dirtyRegion[buffer]); |
| reg.count = 1; |
| reg.rects[0] = uint16_t(bounds.left); |
| reg.rects[1] = uint16_t(bounds.top); |
| reg.rects[2] = uint16_t(bounds.right); |
| reg.rects[3] = uint16_t(bounds.bottom); |
| return NO_ERROR; |
| } |
| |
| Region SharedBufferStack::getDirtyRegion(int buffer) const |
| { |
| Region res; |
| if (uint32_t(buffer) >= NUM_BUFFER_MAX) |
| return res; |
| |
| const FlatRegion& reg(dirtyRegion[buffer]); |
| res.set(Rect(reg.rects[0], reg.rects[1], reg.rects[2], reg.rects[3])); |
| return res; |
| } |
| |
| // ---------------------------------------------------------------------------- |
| |
| SharedBufferBase::SharedBufferBase(SharedClient* sharedClient, |
| int surface, int num, int32_t identity) |
| : mSharedClient(sharedClient), |
| mSharedStack(sharedClient->surfaces + surface), |
| mNumBuffers(num), mIdentity(identity) |
| { |
| } |
| |
| SharedBufferBase::~SharedBufferBase() |
| { |
| } |
| |
| uint32_t SharedBufferBase::getIdentity() |
| { |
| SharedBufferStack& stack( *mSharedStack ); |
| return stack.identity; |
| } |
| |
| status_t SharedBufferBase::getStatus() const |
| { |
| SharedBufferStack& stack( *mSharedStack ); |
| return stack.status; |
| } |
| |
| size_t SharedBufferBase::getFrontBuffer() const |
| { |
| SharedBufferStack& stack( *mSharedStack ); |
| return size_t( stack.head ); |
| } |
| |
| String8 SharedBufferBase::dump(char const* prefix) const |
| { |
| const size_t SIZE = 1024; |
| char buffer[SIZE]; |
| String8 result; |
| SharedBufferStack& stack( *mSharedStack ); |
| snprintf(buffer, SIZE, |
| "%s[ head=%2d, available=%2d, queued=%2d ] " |
| "reallocMask=%08x, inUse=%2d, identity=%d, status=%d\n", |
| prefix, stack.head, stack.available, stack.queued, |
| stack.reallocMask, stack.inUse, stack.identity, stack.status); |
| result.append(buffer); |
| return result; |
| } |
| |
| // ============================================================================ |
| // conditions and updates |
| // ============================================================================ |
| |
| SharedBufferClient::DequeueCondition::DequeueCondition( |
| SharedBufferClient* sbc) : ConditionBase(sbc) { |
| } |
| bool SharedBufferClient::DequeueCondition::operator()() { |
| return stack.available > 0; |
| } |
| |
| SharedBufferClient::LockCondition::LockCondition( |
| SharedBufferClient* sbc, int buf) : ConditionBase(sbc), buf(buf) { |
| } |
| bool SharedBufferClient::LockCondition::operator()() { |
| return (buf != stack.head || |
| (stack.queued > 0 && stack.inUse != buf)); |
| } |
| |
| SharedBufferServer::ReallocateCondition::ReallocateCondition( |
| SharedBufferBase* sbb, int buf) : ConditionBase(sbb), buf(buf) { |
| } |
| bool SharedBufferServer::ReallocateCondition::operator()() { |
| // TODO: we should also check that buf has been dequeued |
| return (buf != stack.head); |
| } |
| |
| // ---------------------------------------------------------------------------- |
| |
| SharedBufferClient::QueueUpdate::QueueUpdate(SharedBufferBase* sbb) |
| : UpdateBase(sbb) { |
| } |
| ssize_t SharedBufferClient::QueueUpdate::operator()() { |
| android_atomic_inc(&stack.queued); |
| return NO_ERROR; |
| } |
| |
| SharedBufferClient::UndoDequeueUpdate::UndoDequeueUpdate(SharedBufferBase* sbb) |
| : UpdateBase(sbb) { |
| } |
| ssize_t SharedBufferClient::UndoDequeueUpdate::operator()() { |
| android_atomic_inc(&stack.available); |
| return NO_ERROR; |
| } |
| |
| SharedBufferServer::UnlockUpdate::UnlockUpdate( |
| SharedBufferBase* sbb, int lockedBuffer) |
| : UpdateBase(sbb), lockedBuffer(lockedBuffer) { |
| } |
| ssize_t SharedBufferServer::UnlockUpdate::operator()() { |
| if (stack.inUse != lockedBuffer) { |
| LOGE("unlocking %d, but currently locked buffer is %d", |
| lockedBuffer, stack.inUse); |
| return BAD_VALUE; |
| } |
| android_atomic_write(-1, &stack.inUse); |
| return NO_ERROR; |
| } |
| |
| SharedBufferServer::RetireUpdate::RetireUpdate( |
| SharedBufferBase* sbb, int numBuffers) |
| : UpdateBase(sbb), numBuffers(numBuffers) { |
| } |
| ssize_t SharedBufferServer::RetireUpdate::operator()() { |
| // head is only written in this function, which is single-thread. |
| int32_t head = stack.head; |
| |
| // Preventively lock the current buffer before updating queued. |
| android_atomic_write(head, &stack.inUse); |
| |
| // Decrement the number of queued buffers |
| int32_t queued; |
| do { |
| queued = stack.queued; |
| if (queued == 0) { |
| return NOT_ENOUGH_DATA; |
| } |
| } while (android_atomic_cmpxchg(queued, queued-1, &stack.queued)); |
| |
| // update the head pointer |
| head = ((head+1 >= numBuffers) ? 0 : head+1); |
| |
| // lock the buffer before advancing head, which automatically unlocks |
| // the buffer we preventively locked upon entering this function |
| android_atomic_write(head, &stack.inUse); |
| |
| // advance head |
| android_atomic_write(head, &stack.head); |
| |
| // now that head has moved, we can increment the number of available buffers |
| android_atomic_inc(&stack.available); |
| return head; |
| } |
| |
| SharedBufferServer::StatusUpdate::StatusUpdate( |
| SharedBufferBase* sbb, status_t status) |
| : UpdateBase(sbb), status(status) { |
| } |
| |
| ssize_t SharedBufferServer::StatusUpdate::operator()() { |
| android_atomic_write(status, &stack.status); |
| return NO_ERROR; |
| } |
| |
| // ============================================================================ |
| |
| SharedBufferClient::SharedBufferClient(SharedClient* sharedClient, |
| int surface, int num, int32_t identity) |
| : SharedBufferBase(sharedClient, surface, num, identity), tail(0) |
| { |
| tail = computeTail(); |
| } |
| |
| int32_t SharedBufferClient::computeTail() const |
| { |
| SharedBufferStack& stack( *mSharedStack ); |
| // we need to make sure we read available and head coherently, |
| // w.r.t RetireUpdate. |
| int32_t newTail; |
| int32_t avail; |
| int32_t head; |
| do { |
| avail = stack.available; |
| head = stack.head; |
| } while (stack.available != avail); |
| newTail = head - avail + 1; |
| if (newTail < 0) { |
| newTail += mNumBuffers; |
| } |
| return newTail; |
| } |
| |
| ssize_t SharedBufferClient::dequeue() |
| { |
| SharedBufferStack& stack( *mSharedStack ); |
| |
| if (stack.head == tail && stack.available == 2) { |
| LOGW("dequeue: tail=%d, head=%d, avail=%d, queued=%d", |
| tail, stack.head, stack.available, stack.queued); |
| } |
| |
| const nsecs_t dequeueTime = systemTime(SYSTEM_TIME_THREAD); |
| |
| //LOGD("[%d] about to dequeue a buffer", |
| // mSharedStack->identity); |
| DequeueCondition condition(this); |
| status_t err = waitForCondition(condition); |
| if (err != NO_ERROR) |
| return ssize_t(err); |
| |
| // NOTE: 'stack.available' is part of the conditions, however |
| // decrementing it, never changes any conditions, so we don't need |
| // to do this as part of an update. |
| if (android_atomic_dec(&stack.available) == 0) { |
| LOGW("dequeue probably called from multiple threads!"); |
| } |
| |
| int dequeued = tail; |
| tail = ((tail+1 >= mNumBuffers) ? 0 : tail+1); |
| LOGD_IF(DEBUG_ATOMICS, "dequeued=%d, tail=%d, %s", |
| dequeued, tail, dump("").string()); |
| |
| mDequeueTime[dequeued] = dequeueTime; |
| |
| return dequeued; |
| } |
| |
| status_t SharedBufferClient::undoDequeue(int buf) |
| { |
| UndoDequeueUpdate update(this); |
| status_t err = updateCondition( update ); |
| if (err == NO_ERROR) { |
| tail = computeTail(); |
| } |
| return err; |
| } |
| |
| status_t SharedBufferClient::lock(int buf) |
| { |
| LockCondition condition(this, buf); |
| status_t err = waitForCondition(condition); |
| return err; |
| } |
| |
| status_t SharedBufferClient::queue(int buf) |
| { |
| QueueUpdate update(this); |
| status_t err = updateCondition( update ); |
| LOGD_IF(DEBUG_ATOMICS, "queued=%d, %s", buf, dump("").string()); |
| SharedBufferStack& stack( *mSharedStack ); |
| const nsecs_t now = systemTime(SYSTEM_TIME_THREAD); |
| stack.stats.totalTime = ns2us(now - mDequeueTime[buf]); |
| return err; |
| } |
| |
| bool SharedBufferClient::needNewBuffer(int buffer) const |
| { |
| SharedBufferStack& stack( *mSharedStack ); |
| const uint32_t mask = 1<<buffer; |
| return (android_atomic_and(~mask, &stack.reallocMask) & mask) != 0; |
| } |
| |
| status_t SharedBufferClient::setDirtyRegion(int buffer, const Region& reg) |
| { |
| SharedBufferStack& stack( *mSharedStack ); |
| return stack.setDirtyRegion(buffer, reg); |
| } |
| |
| // ---------------------------------------------------------------------------- |
| |
| SharedBufferServer::SharedBufferServer(SharedClient* sharedClient, |
| int surface, int num, int32_t identity) |
| : SharedBufferBase(sharedClient, surface, num, identity) |
| { |
| mSharedStack->init(identity); |
| mSharedStack->head = num-1; |
| mSharedStack->available = num; |
| mSharedStack->queued = 0; |
| mSharedStack->reallocMask = 0; |
| memset(mSharedStack->dirtyRegion, 0, sizeof(mSharedStack->dirtyRegion)); |
| } |
| |
| ssize_t SharedBufferServer::retireAndLock() |
| { |
| RetireUpdate update(this, mNumBuffers); |
| ssize_t buf = updateCondition( update ); |
| LOGD_IF(DEBUG_ATOMICS && buf>=0, "retire=%d, %s", int(buf), dump("").string()); |
| return buf; |
| } |
| |
| status_t SharedBufferServer::unlock(int buffer) |
| { |
| UnlockUpdate update(this, buffer); |
| status_t err = updateCondition( update ); |
| return err; |
| } |
| |
| void SharedBufferServer::setStatus(status_t status) |
| { |
| if (status < NO_ERROR) { |
| StatusUpdate update(this, status); |
| updateCondition( update ); |
| } |
| } |
| |
| status_t SharedBufferServer::reallocate() |
| { |
| SharedBufferStack& stack( *mSharedStack ); |
| uint32_t mask = (1<<mNumBuffers)-1; |
| android_atomic_or(mask, &stack.reallocMask); |
| return NO_ERROR; |
| } |
| |
| int32_t SharedBufferServer::getQueuedCount() const |
| { |
| SharedBufferStack& stack( *mSharedStack ); |
| return stack.queued; |
| } |
| |
| status_t SharedBufferServer::assertReallocate(int buffer) |
| { |
| ReallocateCondition condition(this, buffer); |
| status_t err = waitForCondition(condition); |
| return err; |
| } |
| |
| Region SharedBufferServer::getDirtyRegion(int buffer) const |
| { |
| SharedBufferStack& stack( *mSharedStack ); |
| return stack.getDirtyRegion(buffer); |
| } |
| |
| SharedBufferStack::Statistics SharedBufferServer::getStats() const |
| { |
| SharedBufferStack& stack( *mSharedStack ); |
| return stack.stats; |
| } |
| |
| |
| // --------------------------------------------------------------------------- |
| }; // namespace android |