godot/core/command_queue_mt.cpp
Pedro J. Estébanez 18fbdbb456 Reimplement Mutex with C++'s <mutex>
Main:
- It's now implemented thanks to `<mutex>`. No more platform-specific implementations.
- `BinaryMutex` (non-recursive) is added, as an alternative for special cases.
- Doesn't need allocation/deallocation anymore. It can live in the stack and be part of other classes.
- Because of that, it's methods are now `const` and the inner mutex is `mutable` so it can be easily used in `const` contexts.
- A no-op implementation is provided if `NO_THREADS` is defined. No more need to add `#ifdef NO_THREADS` just for this.
- `MutexLock` now takes a reference. At this point the cases of null `Mutex`es are rare. If you ever need that, just don't use `MutexLock`.
- Thread-safe utilities are therefore simpler now.

Misc.:
- `ScopedMutexLock` is dropped and replaced by `MutexLock`, because they were pretty much the same.
- Every case of lock, do-something, unlock is replaced by `MutexLock` (complex cases where it's not straightfoward are kept as as explicit lock and unlock).
- `ShaderRD` contained an `std::mutex`, which has been replaced by `Mutex`.
2020-02-26 20:40:10 +01:00

130 lines
3.7 KiB
C++

/*************************************************************************/
/* command_queue_mt.cpp */
/*************************************************************************/
/* This file is part of: */
/* GODOT ENGINE */
/* https://godotengine.org */
/*************************************************************************/
/* Copyright (c) 2007-2020 Juan Linietsky, Ariel Manzur. */
/* Copyright (c) 2014-2020 Godot Engine contributors (cf. AUTHORS.md). */
/* */
/* Permission is hereby granted, free of charge, to any person obtaining */
/* a copy of this software and associated documentation files (the */
/* "Software"), to deal in the Software without restriction, including */
/* without limitation the rights to use, copy, modify, merge, publish, */
/* distribute, sublicense, and/or sell copies of the Software, and to */
/* permit persons to whom the Software is furnished to do so, subject to */
/* the following conditions: */
/* */
/* The above copyright notice and this permission notice shall be */
/* included in all copies or substantial portions of the Software. */
/* */
/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */
/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF */
/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY */
/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, */
/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE */
/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
/*************************************************************************/
#include "command_queue_mt.h"
#include "core/os/os.h"
void CommandQueueMT::lock() {
mutex.lock();
}
void CommandQueueMT::unlock() {
mutex.unlock();
}
void CommandQueueMT::wait_for_flush() {
// wait one millisecond for a flush to happen
OS::get_singleton()->delay_usec(1000);
}
CommandQueueMT::SyncSemaphore *CommandQueueMT::_alloc_sync_sem() {
int idx = -1;
while (true) {
lock();
for (int i = 0; i < SYNC_SEMAPHORES; i++) {
if (!sync_sems[i].in_use) {
sync_sems[i].in_use = true;
idx = i;
break;
}
}
unlock();
if (idx == -1) {
wait_for_flush();
} else {
break;
}
}
return &sync_sems[idx];
}
bool CommandQueueMT::dealloc_one() {
tryagain:
if (dealloc_ptr == write_ptr) {
// The queue is empty
return false;
}
uint32_t size = *(uint32_t *)&command_mem[dealloc_ptr];
if (size == 0) {
// End of command buffer wrap down
dealloc_ptr = 0;
goto tryagain;
}
if (size & 1) {
// Still used, nothing can be deallocated
return false;
}
dealloc_ptr += (size >> 1) + 8;
return true;
}
CommandQueueMT::CommandQueueMT(bool p_sync) {
read_ptr = 0;
write_ptr = 0;
dealloc_ptr = 0;
command_mem = (uint8_t *)memalloc(COMMAND_MEM_SIZE);
for (int i = 0; i < SYNC_SEMAPHORES; i++) {
sync_sems[i].sem = SemaphoreOld::create();
sync_sems[i].in_use = false;
}
if (p_sync)
sync = SemaphoreOld::create();
else
sync = NULL;
}
CommandQueueMT::~CommandQueueMT() {
if (sync)
memdelete(sync);
for (int i = 0; i < SYNC_SEMAPHORES; i++) {
memdelete(sync_sems[i].sem);
}
memfree(command_mem);
}