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/*
* Copyright (C) 2009 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.
*/
#include "rsLocklessFifo.h"
using namespace android;
LocklessCommandFifo::LocklessCommandFifo()
{
}
LocklessCommandFifo::~LocklessCommandFifo()
{
if (!mInShutdown) {
shutdown();
}
free(mBuffer);
}
void LocklessCommandFifo::shutdown()
{
mInShutdown = true;
mSignalToWorker.set();
}
bool LocklessCommandFifo::init(uint32_t sizeInBytes)
{
// Add room for a buffer reset command
mBuffer = static_cast<uint8_t *>(malloc(sizeInBytes + 4));
if (!mBuffer) {
LOGE("LocklessFifo allocation failure");
return false;
}
if (!mSignalToControl.init() || !mSignalToWorker.init()) {
LOGE("Signal setup failed");
free(mBuffer);
return false;
}
mInShutdown = false;
mSize = sizeInBytes;
mPut = mBuffer;
mGet = mBuffer;
mEnd = mBuffer + (sizeInBytes) - 1;
dumpState("init");
return true;
}
uint32_t LocklessCommandFifo::getFreeSpace() const
{
int32_t freeSpace = 0;
//dumpState("getFreeSpace");
if (mPut >= mGet) {
freeSpace = mEnd - mPut;
} else {
freeSpace = mGet - mPut;
}
if (freeSpace < 0) {
freeSpace = 0;
}
return freeSpace;
}
bool LocklessCommandFifo::isEmpty() const
{
return mPut == mGet;
}
void * LocklessCommandFifo::reserve(uint32_t sizeInBytes)
{
// Add space for command header and loop token;
sizeInBytes += 8;
//dumpState("reserve");
if (getFreeSpace() < sizeInBytes) {
makeSpace(sizeInBytes);
}
return mPut + 4;
}
void LocklessCommandFifo::commit(uint32_t command, uint32_t sizeInBytes)
{
if (mInShutdown) {
return;
}
//dumpState("commit 1");
reinterpret_cast<uint16_t *>(mPut)[0] = command;
reinterpret_cast<uint16_t *>(mPut)[1] = sizeInBytes;
mPut += ((sizeInBytes + 3) & ~3) + 4;
//dumpState("commit 2");
mSignalToWorker.set();
}
void LocklessCommandFifo::commitSync(uint32_t command, uint32_t sizeInBytes)
{
if (mInShutdown) {
return;
}
commit(command, sizeInBytes);
flush();
}
void LocklessCommandFifo::flush()
{
//dumpState("flush 1");
while(mPut != mGet) {
mSignalToControl.wait();
}
//dumpState("flush 2");
}
const void * LocklessCommandFifo::get(uint32_t *command, uint32_t *bytesData)
{
while(1) {
//dumpState("get");
while(isEmpty() && !mInShutdown) {
mSignalToControl.set();
mSignalToWorker.wait();
}
if (mInShutdown) {
*command = 0;
*bytesData = 0;
return 0;
}
*command = reinterpret_cast<const uint16_t *>(mGet)[0];
*bytesData = reinterpret_cast<const uint16_t *>(mGet)[1];
if (*command) {
// non-zero command is valid
return mGet+4;
}
// zero command means reset to beginning.
mGet = mBuffer;
}
}
void LocklessCommandFifo::next()
{
uint32_t bytes = reinterpret_cast<const uint16_t *>(mGet)[1];
mGet += ((bytes + 3) & ~3) + 4;
if (isEmpty()) {
mSignalToControl.set();
}
//dumpState("next");
}
void LocklessCommandFifo::makeSpace(uint32_t bytes)
{
//dumpState("make space");
if ((mPut+bytes) > mEnd) {
// Need to loop regardless of where get is.
while((mGet > mPut) && (mBuffer+4 >= mGet)) {
usleep(100);
}
// Toss in a reset then the normal wait for space will do the rest.
reinterpret_cast<uint16_t *>(mPut)[0] = 0;
reinterpret_cast<uint16_t *>(mPut)[1] = 0;
mPut = mBuffer;
}
// it will fit here so we just need to wait for space.
while(getFreeSpace() < bytes) {
usleep(100);
}
}
void LocklessCommandFifo::dumpState(const char *s) const
{
LOGV("%s put %p, get %p, buf %p, end %p", s, mPut, mGet, mBuffer, mEnd);
}
LocklessCommandFifo::Signal::Signal()
{
mSet = true;
}
LocklessCommandFifo::Signal::~Signal()
{
pthread_mutex_destroy(&mMutex);
pthread_cond_destroy(&mCondition);
}
bool LocklessCommandFifo::Signal::init()
{
int status = pthread_mutex_init(&mMutex, NULL);
if (status) {
LOGE("LocklessFifo mutex init failure");
return false;
}
status = pthread_cond_init(&mCondition, NULL);
if (status) {
LOGE("LocklessFifo condition init failure");
pthread_mutex_destroy(&mMutex);
return false;
}
return true;
}
void LocklessCommandFifo::Signal::set()
{
int status;
status = pthread_mutex_lock(&mMutex);
if (status) {
LOGE("LocklessCommandFifo: error %i locking for set condition.", status);
return;
}
mSet = true;
status = pthread_cond_signal(&mCondition);
if (status) {
LOGE("LocklessCommandFifo: error %i on set condition.", status);
}
status = pthread_mutex_unlock(&mMutex);
if (status) {
LOGE("LocklessCommandFifo: error %i unlocking for set condition.", status);
}
}
void LocklessCommandFifo::Signal::wait()
{
int status;
status = pthread_mutex_lock(&mMutex);
if (status) {
LOGE("LocklessCommandFifo: error %i locking for condition.", status);
return;
}
if (!mSet) {
status = pthread_cond_wait(&mCondition, &mMutex);
if (status) {
LOGE("LocklessCommandFifo: error %i waiting on condition.", status);
}
}
mSet = false;
status = pthread_mutex_unlock(&mMutex);
if (status) {
LOGE("LocklessCommandFifo: error %i unlocking for condition.", status);
}
}