godot/core/command_queue_mt.cpp

/*************************************************************************/
/*  command_queue_mt.cpp                                                 */
/*************************************************************************/
/*                       This file is part of:                           */
/*                           GODOT ENGINE                                */
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/* Copyright (c) 2007-2020 Juan Linietsky, Ariel Manzur.                 */
/* Copyright (c) 2014-2020 Godot Engine contributors (cf. AUTHORS.md).   */
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#include "command_queue_mt.h"
#include "os/os.h"

void CommandQueueMT::lock() {

	if (mutex)
		mutex->lock();
}

void CommandQueueMT::unlock() {

	if (mutex)
		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];
}

CommandQueueMT::CommandQueueMT(bool p_sync) {

	read_ptr = 0;
	write_ptr = 0;
	mutex = Mutex::create();

	for (int i = 0; i < SYNC_SEMAPHORES; i++) {

		sync_sems[i].sem = Semaphore::create();
		sync_sems[i].in_use = false;
	}
	if (p_sync)
		sync = Semaphore::create();
	else
		sync = NULL;
}

CommandQueueMT::~CommandQueueMT() {

	if (sync)
		memdelete(sync);
	memdelete(mutex);
	for (int i = 0; i < SYNC_SEMAPHORES; i++) {

		memdelete(sync_sems[i].sem);
	}
}