queue.c

#include "uwsgi.h"

extern struct uwsgi_server uwsgi;

void uwsgi_init_queue() {
	if (!uwsgi.queue_blocksize)
                        uwsgi.queue_blocksize = 8192;

                if (uwsgi.queue_blocksize % uwsgi.page_size != 0) {
                        uwsgi_log("invalid queue blocksize %llu: must be a multiple of memory page size (%d bytes)\n", (unsigned long long) uwsgi.queue_blocksize, uwsgi.page_size);
                        exit(1);
                }


                uwsgi.shared->queue_pos = 0;
                uwsgi.shared->queue_pull_pos = 0;

                if (uwsgi.queue_store) {
                        uwsgi.queue_filesize = uwsgi.queue_blocksize * uwsgi.queue_size;
                        int queue_fd;
                        struct stat qst;

                        if (stat(uwsgi.queue_store, &qst)) {
                                uwsgi_log("creating a new queue store file: %s\n", uwsgi.queue_store);
                                queue_fd = open(uwsgi.queue_store, O_CREAT | O_RDWR, S_IRUSR | S_IWUSR);
                                if (queue_fd >= 0) {
                                        // fill the queue store
                                        if (ftruncate(queue_fd, uwsgi.queue_filesize)) {
                                                uwsgi_log("ftruncate()");
                                                exit(1);
                                        }
                                }
                        }
                        else {
                                if ((size_t) qst.st_size != uwsgi.queue_filesize || !S_ISREG(qst.st_mode)) {
                                        uwsgi_log("invalid queue store file. Please remove it or fix queue blocksize/items to match its size\n");
                                        exit(1);
                                }
                                queue_fd = open(uwsgi.queue_store, O_CREAT | O_RDWR, S_IRUSR | S_IWUSR);
                                uwsgi_log("recovered queue from backing store file: %s\n", uwsgi.queue_store);
                        }

                        if (queue_fd < 0) {
                                uwsgi_error_open(uwsgi.queue_store);
                                exit(1);
                        }
                        uwsgi.queue = mmap(NULL, uwsgi.queue_filesize, PROT_READ | PROT_WRITE, MAP_SHARED, queue_fd, 0);
                        uwsgi_queue_fix();
                }
                else {
                        uwsgi.queue = mmap(NULL, uwsgi.queue_blocksize * uwsgi.queue_size, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANON, -1, 0);
                }
                if (!uwsgi.queue) {
                        uwsgi_error("mmap()");
                        exit(1);
                }

                uwsgi.queue_lock = uwsgi_mmap_shared_rwlock();
                uwsgi_rwlock_init(uwsgi.queue_lock);

                uwsgi_log("*** Queue subsystem initialized: %dMB preallocated ***\n", (uwsgi.queue_blocksize * uwsgi.queue_size) / (1024 * 1024));
}

char *uwsgi_queue_get(uint64_t index, uint64_t *size) {

	struct uwsgi_queue_item *uqi;
	char *ptr = (char *) uwsgi.queue;

	if (index >= uwsgi.queue_size) return NULL;

	ptr = ptr + (uwsgi.queue_blocksize*index);

	uqi = (struct uwsgi_queue_item *) ptr;
	
	*size = uqi->size;

	return ptr + sizeof(struct uwsgi_queue_item);
	
}

void uwsgi_queue_fix() {

        uint64_t i;
	char *value;
	uint64_t size;

        for(i=0;i< uwsgi.queue_size;i++) {
                // valid record ?
		value = uwsgi_queue_get(i, &size);
		if (value && size) {
			uwsgi.shared->queue_pos++;
		}
		else {
			return;
		}
        }
}


char *uwsgi_queue_pop(uint64_t *size) {

        struct uwsgi_queue_item *uqi;
        char *ptr = (char *) uwsgi.queue;

	if (uwsgi.shared->queue_pos > 0) uwsgi.shared->queue_pos--;

        ptr = ptr + (uwsgi.queue_blocksize*uwsgi.shared->queue_pos);
        uqi = (struct uwsgi_queue_item *) ptr;

        if (!uqi->size) return NULL;

        *size = uqi->size;
	// remove item
	uqi->size = 0;

        return ptr + sizeof(struct uwsgi_queue_item);
}


char *uwsgi_queue_pull(uint64_t *size) {

	struct uwsgi_queue_item *uqi;
	char *ptr = (char *) uwsgi.queue;	

	ptr = ptr + (uwsgi.queue_blocksize*uwsgi.shared->queue_pull_pos);
	uqi = (struct uwsgi_queue_item *) ptr;

	if (!uqi->size) return NULL;

	*size = uqi->size;

	uwsgi.shared->queue_pull_pos++;

	if (uwsgi.shared->queue_pull_pos >= uwsgi.queue_size) uwsgi.shared->queue_pull_pos = 0;

	// remove item
	uqi->size = 0;
	
	return ptr + sizeof(struct uwsgi_queue_item);

}

int uwsgi_queue_push(char *message, uint64_t size) {

	struct uwsgi_queue_item *uqi;
	char *ptr = (char *) uwsgi.queue;

	if (size > uwsgi.queue_blocksize + sizeof(struct uwsgi_queue_item))
		return 0;

	if (!size) return 0;

	ptr = ptr + (uwsgi.queue_blocksize*uwsgi.shared->queue_pos);
	uqi = (struct uwsgi_queue_item *) ptr;

	ptr += sizeof(struct uwsgi_queue_item);

	uqi->size = size;
	uqi->ts = time(NULL);
	memcpy(ptr, message, size);

	uwsgi.shared->queue_pos++;
	
	if (uwsgi.shared->queue_pos >= uwsgi.queue_size) uwsgi.shared->queue_pos = 0;

	return 1;
}