static time_t
ngx_http_file_cache_manager(void *data)
{
ngx_http_file_cache_t *cache = data;
off_t size;
time_t next;
next = ngx_http_file_cache_expire(cache);
cache->last = ngx_current_msec;
cache->files = 0;
for ( ;; ) {
ngx_shmtx_lock(&cache->shpool->mutex);
size = cache->sh->size;
ngx_shmtx_unlock(&cache->shpool->mutex);
ngx_log_debug1(NGX_LOG_DEBUG_HTTP, ngx_cycle->log, 0,
"http file cache size: %O", size);
if (size < cache->max_size) {
return next;
}
next = ngx_http_file_cache_forced_expire(cache);
if (ngx_http_file_cache_manager_sleep(cache) != NGX_OK) {
return next;
}
}
}
static time_t
ngx_http_file_cache_manager(void *data)
{
ngx_http_file_cache_t *cache = data;
off_t size;
time_t next, wait;
// 检查是否有缓存文件过期
next = ngx_http_file_cache_expire(cache);
// 设置缓存最后被访问的时间
cache->last = ngx_current_msec;
cache->files = 0;
for ( ;; ) {
ngx_shmtx_lock(&cache->shpool->mutex);
size = cache->sh->size; // ???
ngx_shmtx_unlock(&cache->shpool->mutex);
ngx_log_debug1(NGX_LOG_DEBUG_HTTP, ngx_cycle->log, 0,
"http file cache size: %O", size);
if (size < cache->max_size) {
return next;
}
wait = ngx_http_file_cache_forced_expire(cache);
if (wait > 0) {
return wait;
}
if (ngx_quit || ngx_terminate) {
return next;
}
}
}
static ngx_int_t
ngx_http_file_cache_exists(ngx_http_file_cache_t *cache, ngx_http_cache_t *c)
{
ngx_int_t rc;
ngx_http_file_cache_node_t *fcn;
ngx_shmtx_lock(&cache->shpool->mutex);
fcn = ngx_http_file_cache_lookup(cache, c->key);
if (fcn) {
ngx_queue_remove(&fcn->queue);
if (fcn->error) {
if (fcn->valid_sec < ngx_time()) {
goto renew;
}
rc = NGX_OK;
goto done;
}
fcn->uses++;
fcn->count++;
if (fcn->exists) {
c->exists = fcn->exists;
c->body_start = fcn->body_start;
rc = NGX_OK;
goto done;
}
if (fcn->uses >= c->min_uses) {
c->exists = fcn->exists;
c->body_start = fcn->body_start;
rc = NGX_OK;
} else {
rc = NGX_AGAIN;
}
goto done;
}
fcn = ngx_slab_alloc_locked(cache->shpool,
sizeof(ngx_http_file_cache_node_t));
if (fcn == NULL) {
ngx_shmtx_unlock(&cache->shpool->mutex);
(void) ngx_http_file_cache_forced_expire(cache);
ngx_shmtx_lock(&cache->shpool->mutex);
fcn = ngx_slab_alloc_locked(cache->shpool,
sizeof(ngx_http_file_cache_node_t));
if (fcn == NULL) {
rc = NGX_ERROR;
goto failed;
}
}
ngx_memcpy((u_char *) &fcn->node.key, c->key, sizeof(ngx_rbtree_key_t));
ngx_memcpy(fcn->key, &c->key[sizeof(ngx_rbtree_key_t)],
NGX_HTTP_CACHE_KEY_LEN - sizeof(ngx_rbtree_key_t));
ngx_rbtree_insert(&cache->sh->rbtree, &fcn->node);
renew:
rc = NGX_DECLINED;
fcn->uses = 1;
fcn->count = 1;
fcn->valid_msec = 0;
fcn->error = 0;
fcn->exists = 0;
fcn->valid_sec = 0;
fcn->uniq = 0;
fcn->body_start = 0;
fcn->length = 0;
done:
fcn->expire = ngx_time() + cache->inactive;
ngx_queue_insert_head(&cache->sh->queue, &fcn->queue);
c->uniq = fcn->uniq;
c->error = fcn->error;
c->node = fcn;
failed:
ngx_shmtx_unlock(&cache->shpool->mutex);
return rc;
}
/*
NGX_OK
NGX_AGAIN
NGX_ERROR
NGX_DECLINED: cache索引表中没有查找到，创建node并插入到红黑树和队列中，并且设置node节点到 c->node
*/
static ngx_int_t
ngx_http_file_cache_exists(ngx_http_file_cache_t *cache, ngx_http_cache_t *c)
{
ngx_int_t rc;
ngx_http_file_cache_node_t *fcn;
// 对共享内存区上锁
ngx_shmtx_lock(&cache->shpool->mutex); // 在函数 ngx_init_zone_pool（）中设置并创建
fcn = c->node;
if (fcn == NULL) {
// 在cache中查找key
fcn = ngx_http_file_cache_lookup(cache, c->key);
}
// 在共享内存中找到cache
if (fcn) {
// 在队列中删除？？？？
ngx_queue_remove(&fcn->queue);
// ????
if (c->node == NULL) {
fcn->uses++;
fcn->count++;
}
// ????
if (fcn->error) {
if (fcn->valid_sec < ngx_time()) {
goto renew;
}
rc = NGX_OK;
goto done;
}
if (fcn->exists || fcn->uses >= c->min_uses) {
c->exists = fcn->exists;
if (fcn->body_start) {
c->body_start = fcn->body_start;
}
rc = NGX_OK;
goto done;
}
rc = NGX_AGAIN;
goto done;
}
//################ 在共享内存cache索引表中没有查找到此cache ################
// 1. 申请一个cache节点
fcn = ngx_slab_alloc_locked(cache->shpool,
sizeof(ngx_http_file_cache_node_t));
if (fcn == NULL) {
// 共享内存空间不足申请一个cache节点时，强制过期一个cache节点
ngx_shmtx_unlock(&cache->shpool->mutex);
(void) ngx_http_file_cache_forced_expire(cache);
ngx_shmtx_lock(&cache->shpool->mutex);
fcn = ngx_slab_alloc_locked(cache->shpool,
sizeof(ngx_http_file_cache_node_t));
if (fcn == NULL) {
rc = NGX_ERROR;
goto failed;
}
}
// 2. 拷贝节点key
ngx_memcpy((u_char *) &fcn->node.key, c->key, sizeof(ngx_rbtree_key_t));
ngx_memcpy(fcn->key, &c->key[sizeof(ngx_rbtree_key_t)],
NGX_HTTP_CACHE_KEY_LEN - sizeof(ngx_rbtree_key_t));
// 3. 插入到红黑树中
ngx_rbtree_insert(&cache->sh->rbtree, &fcn->node);
fcn->uses = 1;
fcn->count = 1;
fcn->updating = 0;
fcn->deleting = 0;
renew:
rc = NGX_DECLINED;
fcn->valid_msec = 0;
fcn->error = 0;
fcn->exists = 0;
fcn->valid_sec = 0;
fcn->uniq = 0;
fcn->body_start = 0;
fcn->fs_size = 0;
done:
fcn->expire = ngx_time() + cache->inactive;
ngx_queue_insert_head(&cache->sh->queue, &fcn->queue);
c->uniq = fcn->uniq;
c->error = fcn->error;
c->node = fcn; // 设置node节点
failed:
ngx_shmtx_unlock(&cache->shpool->mutex);
return rc;
}
