text: 
  /*
   * Copyright (C) Igor Sysoev
   * Copyright (C) Nginx, Inc.
   */
  
  
  #include <ngx_config.h>
  #include <ngx_core.h>
  #include <ngx_http.h>
  #include <ngx_md5.h>
  
  
  static ngx_int_t ngx_http_file_cache_lock(ngx_http_request_t *r,
      ngx_http_cache_t *c);
  static void ngx_http_file_cache_lock_wait_handler(ngx_event_t *ev);
  static void ngx_http_file_cache_lock_wait(ngx_http_request_t *r,
      ngx_http_cache_t *c);
  static ngx_int_t ngx_http_file_cache_read(ngx_http_request_t *r,
      ngx_http_cache_t *c);
  static ssize_t ngx_http_file_cache_aio_read(ngx_http_request_t *r,
      ngx_http_cache_t *c);
  #if (NGX_HAVE_FILE_AIO)
  static void ngx_http_cache_aio_event_handler(ngx_event_t *ev);
  #endif
  #if (NGX_THREADS)
  static ngx_int_t ngx_http_cache_thread_handler(ngx_thread_task_t *task,
      ngx_file_t *file);
  static void ngx_http_cache_thread_event_handler(ngx_event_t *ev);
  #endif
  static ngx_int_t ngx_http_file_cache_exists(ngx_http_file_cache_t *cache,
      ngx_http_cache_t *c);
  static ngx_int_t ngx_http_file_cache_name(ngx_http_request_t *r,
      ngx_path_t *path);
  static ngx_http_file_cache_node_t *
      ngx_http_file_cache_lookup(ngx_http_file_cache_t *cache, u_char *key);
  static void ngx_http_file_cache_rbtree_insert_value(ngx_rbtree_node_t *temp,
      ngx_rbtree_node_t *node, ngx_rbtree_node_t *sentinel);
  static void ngx_http_file_cache_vary(ngx_http_request_t *r, u_char *vary,
      size_t len, u_char *hash);
  static void ngx_http_file_cache_vary_header(ngx_http_request_t *r,
      ngx_md5_t *md5, ngx_str_t *name);
  static ngx_int_t ngx_http_file_cache_reopen(ngx_http_request_t *r,
      ngx_http_cache_t *c);
  static ngx_int_t ngx_http_file_cache_update_variant(ngx_http_request_t *r,
      ngx_http_cache_t *c);
  static void ngx_http_file_cache_cleanup(void *data);
  static time_t ngx_http_file_cache_forced_expire(ngx_http_file_cache_t *cache);
  static time_t ngx_http_file_cache_expire(ngx_http_file_cache_t *cache);
  static void ngx_http_file_cache_delete(ngx_http_file_cache_t *cache,
      ngx_queue_t *q, u_char *name);
  static void ngx_http_file_cache_loader_sleep(ngx_http_file_cache_t *cache);
  static ngx_int_t ngx_http_file_cache_noop(ngx_tree_ctx_t *ctx,
      ngx_str_t *path);
  static ngx_int_t ngx_http_file_cache_manage_file(ngx_tree_ctx_t *ctx,
      ngx_str_t *path);
  static ngx_int_t ngx_http_file_cache_manage_directory(ngx_tree_ctx_t *ctx,
      ngx_str_t *path);
  static ngx_int_t ngx_http_file_cache_add_file(ngx_tree_ctx_t *ctx,
      ngx_str_t *path);
  static ngx_int_t ngx_http_file_cache_add(ngx_http_file_cache_t *cache,
      ngx_http_cache_t *c);
  static ngx_int_t ngx_http_file_cache_delete_file(ngx_tree_ctx_t *ctx,
      ngx_str_t *path);
  static void ngx_http_file_cache_set_watermark(ngx_http_file_cache_t *cache);
  
  
  ngx_str_t  ngx_http_cache_status[] = {
      ngx_string("MISS"),
      ngx_string("BYPASS"),
      ngx_string("EXPIRED"),
      ngx_string("STALE"),
      ngx_string("UPDATING"),
      ngx_string("REVALIDATED"),
      ngx_string("HIT")
  };
  
  
  static u_char  ngx_http_file_cache_key[] = { LF, 'K', 'E', 'Y', ':', ' ' };
  
  
  static ngx_int_t
  ngx_http_file_cache_init(ngx_shm_zone_t *shm_zone, void *data)
  {
      ngx_http_file_cache_t  *ocache = data;
  
      size_t                  len;
      ngx_uint_t              n;
      ngx_http_file_cache_t  *cache;
  
      cache = shm_zone->data;
  
      if (ocache) {
          if (ngx_strcmp(cache->path->name.data, ocache->path->name.data) != 0) {
              ngx_log_error(NGX_LOG_EMERG, shm_zone->shm.log, 0,
                            "cache \"%V\" uses the \"%V\" cache path "
                            "while previously it used the \"%V\" cache path",
                            &shm_zone->shm.name, &cache->path->name,
                            &ocache->path->name);
  
              return NGX_ERROR;
          }
  
          for (n = 0; n < 3; n++) {
              if (cache->path->level[n] != ocache->path->level[n]) {
                  ngx_log_error(NGX_LOG_EMERG, shm_zone->shm.log, 0,
                                "cache \"%V\" had previously different levels",
                                &shm_zone->shm.name);
                  return NGX_ERROR;
              }
          }
  
          cache->sh = ocache->sh;
  
          cache->shpool = ocache->shpool;
          cache->bsize = ocache->bsize;
  
          cache->max_size /= cache->bsize;
  
          if (!cache->sh->cold || cache->sh->loading) {
              cache->path->loader = NULL;
          }
  
          return NGX_OK;
      }
  
      cache->shpool = (ngx_slab_pool_t *) shm_zone->shm.addr;
  
      if (shm_zone->shm.exists) {
          cache->sh = cache->shpool->data;
          cache->bsize = ngx_fs_bsize(cache->path->name.data);
  
          return NGX_OK;
      }
  
      cache->sh = ngx_slab_alloc(cache->shpool, sizeof(ngx_http_file_cache_sh_t));
      if (cache->sh == NULL) {
          return NGX_ERROR;
      }
  
      cache->shpool->data = cache->sh;
  
      ngx_rbtree_init(&cache->sh->rbtree, &cache->sh->sentinel,
                      ngx_http_file_cache_rbtree_insert_value);
  
      ngx_queue_init(&cache->sh->queue);
  
      cache->sh->cold = 1;
      cache->sh->loading = 0;
      cache->sh->size = 0;
      cache->sh->count = 0;
      cache->sh->watermark = (ngx_uint_t) -1;
  
      cache->bsize = ngx_fs_bsize(cache->path->name.data);
  
      cache->max_size /= cache->bsize;
  
      len = sizeof(" in cache keys zone \"\"") + shm_zone->shm.name.len;
  
      cache->shpool->log_ctx = ngx_slab_alloc(cache->shpool, len);
      if (cache->shpool->log_ctx == NULL) {
          return NGX_ERROR;
      }
  
      ngx_sprintf(cache->shpool->log_ctx, " in cache keys zone \"%V\"%Z",
                  &shm_zone->shm.name);
  
      cache->shpool->log_nomem = 0;
  
      return NGX_OK;
  }
  
  
  ngx_int_t
  ngx_http_file_cache_new(ngx_http_request_t *r)
  {
      ngx_http_cache_t  *c;
  
      c = ngx_pcalloc(r->pool, sizeof(ngx_http_cache_t));
      if (c == NULL) {
          return NGX_ERROR;
      }
  
      if (ngx_array_init(&c->keys, r->pool, 4, sizeof(ngx_str_t)) != NGX_OK) {
          return NGX_ERROR;
      }
  
      r->cache = c;
      c->file.log = r->connection->log;
      c->file.fd = NGX_INVALID_FILE;
  
      return NGX_OK;
  }
  
  
  ngx_int_t
  ngx_http_file_cache_create(ngx_http_request_t *r)
  {
      ngx_http_cache_t       *c;
      ngx_pool_cleanup_t     *cln;
      ngx_http_file_cache_t  *cache;
  
      c = r->cache;
      cache = c->file_cache;
  
      cln = ngx_pool_cleanup_add(r->pool, 0);
      if (cln == NULL) {
          return NGX_ERROR;
      }
  
      cln->handler = ngx_http_file_cache_cleanup;
      cln->data = c;
  
      if (ngx_http_file_cache_exists(cache, c) == NGX_ERROR) {
          return NGX_ERROR;
      }
  
      if (ngx_http_file_cache_name(r, cache->path) != NGX_OK) {
          return NGX_ERROR;
      }
  
      return NGX_OK;
  }
  
  
  void
  ngx_http_file_cache_create_key(ngx_http_request_t *r)
  {
      size_t             len;
      ngx_str_t         *key;
      ngx_uint_t         i;
      ngx_md5_t          md5;
      ngx_http_cache_t  *c;
  
      c = r->cache;
  
      len = 0;
  
      ngx_crc32_init(c->crc32);
      ngx_md5_init(&md5);
  
      key = c->keys.elts;
      for (i = 0; i < c->keys.nelts; i++) {
          ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                         "http cache key: \"%V\"", &key[i]);
  
          len += key[i].len;
  
          ngx_crc32_update(&c->crc32, key[i].data, key[i].len);
          ngx_md5_update(&md5, key[i].data, key[i].len);
      }
  
      c->header_start = sizeof(ngx_http_file_cache_header_t)
                        + sizeof(ngx_http_file_cache_key) + len + 1;
  
      ngx_crc32_final(c->crc32);
      ngx_md5_final(c->key, &md5);
  
      ngx_memcpy(c->main, c->key, NGX_HTTP_CACHE_KEY_LEN);
  }
  
  
  ngx_int_t
  ngx_http_file_cache_open(ngx_http_request_t *r)
  {
      ngx_int_t                  rc, rv;
      ngx_uint_t                 test;
      ngx_http_cache_t          *c;
      ngx_pool_cleanup_t        *cln;
      ngx_open_file_info_t       of;
      ngx_http_file_cache_t     *cache;
      ngx_http_core_loc_conf_t  *clcf;
  
      c = r->cache;
  
      if (c->waiting) {
          return NGX_AGAIN;
      }
  
      if (c->reading) {
          return ngx_http_file_cache_read(r, c);
      }
  
      cache = c->file_cache;
  
      if (c->node == NULL) {
          cln = ngx_pool_cleanup_add(r->pool, 0);
          if (cln == NULL) {
              return NGX_ERROR;
          }
  
          cln->handler = ngx_http_file_cache_cleanup;
          cln->data = c;
      }
  
      rc = ngx_http_file_cache_exists(cache, c);
  
      ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                     "http file cache exists: %i e:%d", rc, c->exists);
  
      if (rc == NGX_ERROR) {
          return rc;
      }
  
      if (rc == NGX_AGAIN) {
          return NGX_HTTP_CACHE_SCARCE;
      }
  
      if (rc == NGX_OK) {
  
          if (c->error) {
              return c->error;
          }
  
          c->temp_file = 1;
          test = c->exists ? 1 : 0;
          rv = NGX_DECLINED;
  
      } else { /* rc == NGX_DECLINED */
  
          test = cache->sh->cold ? 1 : 0;
  
          if (c->min_uses > 1) {
  
              if (!test) {
                  return NGX_HTTP_CACHE_SCARCE;
              }
  
              rv = NGX_HTTP_CACHE_SCARCE;
  
          } else {
              c->temp_file = 1;
              rv = NGX_DECLINED;
          }
      }
  
      if (ngx_http_file_cache_name(r, cache->path) != NGX_OK) {
          return NGX_ERROR;
      }
  
      if (!test) {
          goto done;
      }
  
      clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);
  
      ngx_memzero(&of, sizeof(ngx_open_file_info_t));
  
      of.uniq = c->uniq;
      of.valid = clcf->open_file_cache_valid;
      of.min_uses = clcf->open_file_cache_min_uses;
      of.events = clcf->open_file_cache_events;
      of.directio = NGX_OPEN_FILE_DIRECTIO_OFF;
      of.read_ahead = clcf->read_ahead;
  
      if (ngx_open_cached_file(clcf->open_file_cache, &c->file.name, &of, r->pool)
          != NGX_OK)
      {
          switch (of.err) {
  
          case 0:
              return NGX_ERROR;
  
          case NGX_ENOENT:
          case NGX_ENOTDIR:
              goto done;
  
          default:
              ngx_log_error(NGX_LOG_CRIT, r->connection->log, of.err,
                            ngx_open_file_n " \"%s\" failed", c->file.name.data);
              return NGX_ERROR;
          }
      }
  
      ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                     "http file cache fd: %d", of.fd);
  
      c->file.fd = of.fd;
      c->file.log = r->connection->log;
      c->uniq = of.uniq;
      c->length = of.size;
      c->fs_size = (of.fs_size + cache->bsize - 1) / cache->bsize;
  
      c->buf = ngx_create_temp_buf(r->pool, c->body_start);
      if (c->buf == NULL) {
          return NGX_ERROR;
      }
  
      return ngx_http_file_cache_read(r, c);
  
  done:
  
      if (rv == NGX_DECLINED) {
          return ngx_http_file_cache_lock(r, c);
      }
  
      return rv;
  }
  
  
  static ngx_int_t
  ngx_http_file_cache_lock(ngx_http_request_t *r, ngx_http_cache_t *c)
  {
      ngx_msec_t                 now, timer;
      ngx_http_file_cache_t     *cache;
  
      if (!c->lock) {
          return NGX_DECLINED;
      }
  
      now = ngx_current_msec;
  
      cache = c->file_cache;
  
      ngx_shmtx_lock(&cache->shpool->mutex);
  
      timer = c->node->lock_time - now;
  
      if (!c->node->updating || (ngx_msec_int_t) timer <= 0) {
          c->node->updating = 1;
          c->node->lock_time = now + c->lock_age;
          c->updating = 1;
          c->lock_time = c->node->lock_time;
      }
  
      ngx_shmtx_unlock(&cache->shpool->mutex);
  
      ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                     "http file cache lock u:%d wt:%M",
                     c->updating, c->wait_time);
  
      if (c->updating) {
          return NGX_DECLINED;
      }
  
      if (c->lock_timeout == 0) {
          return NGX_HTTP_CACHE_SCARCE;
      }
  
      c->waiting = 1;
  
      if (c->wait_time == 0) {
          c->wait_time = now + c->lock_timeout;
  
          c->wait_event.handler = ngx_http_file_cache_lock_wait_handler;
          c->wait_event.data = r;
          c->wait_event.log = r->connection->log;
      }
  
      timer = c->wait_time - now;
  
      ngx_add_timer(&c->wait_event, (timer > 500) ? 500 : timer);
  
      r->main->blocked++;
  
      return NGX_AGAIN;
  }
  
  
  static void
  ngx_http_file_cache_lock_wait_handler(ngx_event_t *ev)
  {
      ngx_connection_t    *c;
      ngx_http_request_t  *r;
  
      r = ev->data;
      c = r->connection;
  
      ngx_http_set_log_request(c->log, r);
  
      ngx_log_debug2(NGX_LOG_DEBUG_HTTP, c->log, 0,
                     "http file cache wait: \"%V?%V\"", &r->uri, &r->args);
  
      ngx_http_file_cache_lock_wait(r, r->cache);
  
      ngx_http_run_posted_requests(c);
  }
  
  
  static void
  ngx_http_file_cache_lock_wait(ngx_http_request_t *r, ngx_http_cache_t *c)
  {
      ngx_uint_t              wait;
      ngx_msec_t              now, timer;
      ngx_http_file_cache_t  *cache;
  
      now = ngx_current_msec;
  
      timer = c->wait_time - now;
  
      if ((ngx_msec_int_t) timer <= 0) {
          ngx_log_error(NGX_LOG_INFO, r->connection->log, 0,
                        "cache lock timeout");
          c->lock_timeout = 0;
          goto wakeup;
      }
  
      cache = c->file_cache;
      wait = 0;
  
      ngx_shmtx_lock(&cache->shpool->mutex);
  
      timer = c->node->lock_time - now;
  
      if (c->node->updating && (ngx_msec_int_t) timer > 0) {
          wait = 1;
      }
  
      ngx_shmtx_unlock(&cache->shpool->mutex);
  
      if (wait) {
          ngx_add_timer(&c->wait_event, (timer > 500) ? 500 : timer);
          return;
      }
  
  wakeup:
  
      c->waiting = 0;
      r->main->blocked--;
      r->write_event_handler(r);
  }
  
  
  static ngx_int_t
  ngx_http_file_cache_read(ngx_http_request_t *r, ngx_http_cache_t *c)
  {
      u_char                        *p;
      time_t                         now;
      ssize_t                        n;
      ngx_str_t                     *key;
      ngx_int_t                      rc;
      ngx_uint_t                     i;
      ngx_http_file_cache_t         *cache;
      ngx_http_file_cache_header_t  *h;
  
      n = ngx_http_file_cache_aio_read(r, c);
  
      if (n < 0) {
          return n;
      }
  
      if ((size_t) n < c->header_start) {
          ngx_log_error(NGX_LOG_CRIT, r->connection->log, 0,
                        "cache file \"%s\" is too small", c->file.name.data);
          return NGX_DECLINED;
      }
  
      h = (ngx_http_file_cache_header_t *) c->buf->pos;
  
      if (h->version != NGX_HTTP_CACHE_VERSION) {
          ngx_log_error(NGX_LOG_INFO, r->connection->log, 0,
                        "cache file \"%s\" version mismatch", c->file.name.data);
          return NGX_DECLINED;
      }
  
      if (h->crc32 != c->crc32 || h->header_start != c->header_start) {
          ngx_log_error(NGX_LOG_CRIT, r->connection->log, 0,
                        "cache file \"%s\" has md5 collision", c->file.name.data);
          return NGX_DECLINED;
      }
  
      p = c->buf->pos + sizeof(ngx_http_file_cache_header_t)
          + sizeof(ngx_http_file_cache_key);
  
      key = c->keys.elts;
      for (i = 0; i < c->keys.nelts; i++) {
          if (ngx_memcmp(p, key[i].data, key[i].len) != 0) {
              ngx_log_error(NGX_LOG_CRIT, r->connection->log, 0,
                            "cache file \"%s\" has md5 collision",
                            c->file.name.data);
              return NGX_DECLINED;
          }
  
          p += key[i].len;
      }
  
      if ((size_t) h->body_start > c->body_start) {
          ngx_log_error(NGX_LOG_CRIT, r->connection->log, 0,
                        "cache file \"%s\" has too long header",
                        c->file.name.data);
          return NGX_DECLINED;
      }
  
      if (h->vary_len > NGX_HTTP_CACHE_VARY_LEN) {
          ngx_log_error(NGX_LOG_CRIT, r->connection->log, 0,
                        "cache file \"%s\" has incorrect vary length",
                        c->file.name.data);
          return NGX_DECLINED;
      }
  
      if (h->vary_len) {
          ngx_http_file_cache_vary(r, h->vary, h->vary_len, c->variant);
  
          if (ngx_memcmp(c->variant, h->variant, NGX_HTTP_CACHE_KEY_LEN) != 0) {
              ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                             "http file cache vary mismatch");
              return ngx_http_file_cache_reopen(r, c);
          }
      }
  
      c->buf->last += n;
  
      c->valid_sec = h->valid_sec;
      c->last_modified = h->last_modified;
      c->date = h->date;
      c->valid_msec = h->valid_msec;
      c->body_start = h->body_start;
      c->etag.len = h->etag_len;
      c->etag.data = h->etag;
  
      r->cached = 1;
  
      cache = c->file_cache;
  
      if (cache->sh->cold) {
  
          ngx_shmtx_lock(&cache->shpool->mutex);
  
          if (!c->node->exists) {
              c->node->uses = 1;
              c->node->body_start = c->body_start;
              c->node->exists = 1;
              c->node->uniq = c->uniq;
              c->node->fs_size = c->fs_size;
  
              cache->sh->size += c->fs_size;
          }
  
          ngx_shmtx_unlock(&cache->shpool->mutex);
      }
  
      now = ngx_time();
  
      if (c->valid_sec < now) {
  
          ngx_shmtx_lock(&cache->shpool->mutex);
  
          if (c->node->updating) {
              rc = NGX_HTTP_CACHE_UPDATING;
  
          } else {
              c->node->updating = 1;
              c->updating = 1;
              c->lock_time = c->node->lock_time;
              rc = NGX_HTTP_CACHE_STALE;
          }
  
          ngx_shmtx_unlock(&cache->shpool->mutex);
  
          ngx_log_debug3(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                         "http file cache expired: %i %T %T",
                         rc, c->valid_sec, now);
  
          return rc;
      }
  
      return NGX_OK;
  }
  
  
  static ssize_t
  ngx_http_file_cache_aio_read(ngx_http_request_t *r, ngx_http_cache_t *c)
  {
  #if (NGX_HAVE_FILE_AIO || NGX_THREADS)
      ssize_t                    n;
      ngx_http_core_loc_conf_t  *clcf;
  
      clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);
  #endif
  
  #if (NGX_HAVE_FILE_AIO)
  
      if (clcf->aio == NGX_HTTP_AIO_ON && ngx_file_aio) {
          n = ngx_file_aio_read(&c->file, c->buf->pos, c->body_start, 0, r->pool);
  
          if (n != NGX_AGAIN) {
              c->reading = 0;
              return n;
          }
  
          c->reading = 1;
  
          c->file.aio->data = r;
          c->file.aio->handler = ngx_http_cache_aio_event_handler;
  
          r->main->blocked++;
          r->aio = 1;
  
          return NGX_AGAIN;
      }
  
  #endif
  
  #if (NGX_THREADS)
  
      if (clcf->aio == NGX_HTTP_AIO_THREADS) {
          c->file.thread_task = c->thread_task;
          c->file.thread_handler = ngx_http_cache_thread_handler;
          c->file.thread_ctx = r;
  
          n = ngx_thread_read(&c->file, c->buf->pos, c->body_start, 0, r->pool);
  
          c->thread_task = c->file.thread_task;
          c->reading = (n == NGX_AGAIN);
  
          return n;
      }
  
  #endif
  
      return ngx_read_file(&c->file, c->buf->pos, c->body_start, 0);
  }
  
  
  #if (NGX_HAVE_FILE_AIO)
  
  static void
  ngx_http_cache_aio_event_handler(ngx_event_t *ev)
  {
      ngx_event_aio_t     *aio;
      ngx_connection_t    *c;
      ngx_http_request_t  *r;
  
      aio = ev->data;
      r = aio->data;
      c = r->connection;
  
      ngx_http_set_log_request(c->log, r);
  
      ngx_log_debug2(NGX_LOG_DEBUG_HTTP, c->log, 0,
                     "http file cache aio: \"%V?%V\"", &r->uri, &r->args);
  
      r->main->blocked--;
      r->aio = 0;
  
      r->write_event_handler(r);
  
      ngx_http_run_posted_requests(c);
  }
  
  #endif
  
  
  #if (NGX_THREADS)
  
  static ngx_int_t
  ngx_http_cache_thread_handler(ngx_thread_task_t *task, ngx_file_t *file)
  {
      ngx_str_t                  name;
      ngx_thread_pool_t         *tp;
      ngx_http_request_t        *r;
      ngx_http_core_loc_conf_t  *clcf;
  
      r = file->thread_ctx;
  
      clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);
      tp = clcf->thread_pool;
  
      if (tp == NULL) {
          if (ngx_http_complex_value(r, clcf->thread_pool_value, &name)
              != NGX_OK)
          {
              return NGX_ERROR;
          }
  
          tp = ngx_thread_pool_get((ngx_cycle_t *) ngx_cycle, &name);
  
          if (tp == NULL) {
              ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
                            "thread pool \"%V\" not found", &name);
              return NGX_ERROR;
          }
      }
  
      task->event.data = r;
      task->event.handler = ngx_http_cache_thread_event_handler;
  
      if (ngx_thread_task_post(tp, task) != NGX_OK) {
          return NGX_ERROR;
      }
  
      r->main->blocked++;
      r->aio = 1;
  
      return NGX_OK;
  }
  
  
  static void
  ngx_http_cache_thread_event_handler(ngx_event_t *ev)
  {
      ngx_connection_t    *c;
      ngx_http_request_t  *r;
  
      r = ev->data;
      c = r->connection;
  
      ngx_http_set_log_request(c->log, r);
  
      ngx_log_debug2(NGX_LOG_DEBUG_HTTP, c->log, 0,
                     "http file cache thread: \"%V?%V\"", &r->uri, &r->args);
  
      r->main->blocked--;
      r->aio = 0;
  
      r->write_event_handler(r);
  
      ngx_http_run_posted_requests(c);
  }
  
  #endif
  
  
  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 = c->node;
  
      if (fcn == NULL) {
          fcn = ngx_http_file_cache_lookup(cache, c->key);
      }
  
      if (fcn) {
          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;
      }
  
      fcn = ngx_slab_calloc_locked(cache->shpool,
                                   sizeof(ngx_http_file_cache_node_t));
      if (fcn == NULL) {
          ngx_http_file_cache_set_watermark(cache);
  
          ngx_shmtx_unlock(&cache->shpool->mutex);
  
          (void) ngx_http_file_cache_forced_expire(cache);
  
          ngx_shmtx_lock(&cache->shpool->mutex);
  
          fcn = ngx_slab_calloc_locked(cache->shpool,
                                       sizeof(ngx_http_file_cache_node_t));
          if (fcn == NULL) {
              ngx_log_error(NGX_LOG_ALERT, ngx_cycle->log, 0,
                            "could not allocate node%s", cache->shpool->log_ctx);
              rc = NGX_ERROR;
              goto failed;
          }
      }
  
      cache->sh->count++;
  
      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);
  
      fcn->uses = 1;
      fcn->count = 1;
  
  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;
  
  failed:
  
      ngx_shmtx_unlock(&cache->shpool->mutex);
  
      return rc;
  }
  
  
  static ngx_int_t
  ngx_http_file_cache_name(ngx_http_request_t *r, ngx_path_t *path)
  {
      u_char            *p;
      ngx_http_cache_t  *c;
  
      c = r->cache;
  
      if (c->file.name.len) {
          return NGX_OK;
      }
  
      c->file.name.len = path->name.len + 1 + path->len
                         + 2 * NGX_HTTP_CACHE_KEY_LEN;
  
      c->file.name.data = ngx_pnalloc(r->pool, c->file.name.len + 1);
      if (c->file.name.data == NULL) {
          return NGX_ERROR;
      }
  
      ngx_memcpy(c->file.name.data, path->name.data, path->name.len);
  
      p = c->file.name.data + path->name.len + 1 + path->len;
      p = ngx_hex_dump(p, c->key, NGX_HTTP_CACHE_KEY_LEN);
      *p = '\0';
  
      ngx_create_hashed_filename(path, c->file.name.data, c->file.name.len);
  
      ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                     "cache file: \"%s\"", c->file.name.data);
  
      return NGX_OK;
  }
  
  
  static ngx_http_file_cache_node_t *
  ngx_http_file_cache_lookup(ngx_http_file_cache_t *cache, u_char *key)
  {
      ngx_int_t                    rc;
      ngx_rbtree_key_t             node_key;
      ngx_rbtree_node_t           *node, *sentinel;
      ngx_http_file_cache_node_t  *fcn;
  
      ngx_memcpy((u_char *) &node_key, key, sizeof(ngx_rbtree_key_t));
  
      node = cache->sh->rbtree.root;
      sentinel = cache->sh->rbtree.sentinel;
  
      while (node != sentinel) {
  
          if (node_key < node->key) {
              node = node->left;
              continue;
          }
  
          if (node_key > node->key) {
              node = node->right;
              continue;
          }
  
          /* node_key == node->key */
  
          fcn = (ngx_http_file_cache_node_t *) node;
  
          rc = ngx_memcmp(&key[sizeof(ngx_rbtree_key_t)], fcn->key,
                          NGX_HTTP_CACHE_KEY_LEN - sizeof(ngx_rbtree_key_t));
  
          if (rc == 0) {
              return fcn;
          }
  
          node = (rc < 0) ? node->left : node->right;
      }
  
      /* not found */
  
      return NULL;
  }
  
  
  static void
  ngx_http_file_cache_rbtree_insert_value(ngx_rbtree_node_t *temp,
      ngx_rbtree_node_t *node, ngx_rbtree_node_t *sentinel)
  {
      ngx_rbtree_node_t           **p;
      ngx_http_file_cache_node_t   *cn, *cnt;
  
      for ( ;; ) {
  
          if (node->key < temp->key) {
  
              p = &temp->left;
  
          } else if (node->key > temp->key) {
  
              p = &temp->right;
  
          } else { /* node->key == temp->key */
  
              cn = (ngx_http_file_cache_node_t *) node;
              cnt = (ngx_http_file_cache_node_t *) temp;
  
              p = (ngx_memcmp(cn->key, cnt->key,
                              NGX_HTTP_CACHE_KEY_LEN - sizeof(ngx_rbtree_key_t))
                   < 0)
                      ? &temp->left : &temp->right;
          }
  
          if (*p == sentinel) {
              break;
          }
  
          temp = *p;
      }
  
      *p = node;
      node->parent = temp;
      node->left = sentinel;
      node->right = sentinel;
      ngx_rbt_red(node);
  }
  
  
  static void
  ngx_http_file_cache_vary(ngx_http_request_t *r, u_char *vary, size_t len,
      u_char *hash)
  {
      u_char     *p, *last;
      ngx_str_t   name;
      ngx_md5_t   md5;
      u_char      buf[NGX_HTTP_CACHE_VARY_LEN];
  
      ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                     "http file cache vary: \"%*s\"", len, vary);
  
      ngx_md5_init(&md5);
      ngx_md5_update(&md5, r->cache->main, NGX_HTTP_CACHE_KEY_LEN);
  
      ngx_strlow(buf, vary, len);
  
      p = buf;
      last = buf + len;
  
      while (p < last) {
  
          while (p < last && (*p == ' ' || *p == ',')) { p++; }
  
          name.data = p;
  
          while (p < last && *p != ',' && *p != ' ') { p++; }
  
          name.len = p - name.data;
  
          if (name.len == 0) {
              break;
          }
  
          ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                         "http file cache vary: %V", &name);
  
          ngx_md5_update(&md5, name.data, name.len);
          ngx_md5_update(&md5, (u_char *) ":", sizeof(":") - 1);
  
          ngx_http_file_cache_vary_header(r, &md5, &name);
  
          ngx_md5_update(&md5, (u_char *) CRLF, sizeof(CRLF) - 1);
      }
  
      ngx_md5_final(hash, &md5);
  }
  
  
  static void
  ngx_http_file_cache_vary_header(ngx_http_request_t *r, ngx_md5_t *md5,
      ngx_str_t *name)
  {
      size_t            len;
      u_char           *p, *start, *last;
      ngx_uint_t        i, multiple, normalize;
      ngx_list_part_t  *part;
      ngx_table_elt_t  *header;
  
      multiple = 0;
      normalize = 0;
  
      if (name->len == sizeof("Accept-Charset") - 1
          && ngx_strncasecmp(name->data, (u_char *) "Accept-Charset",
                             sizeof("Accept-Charset") - 1) == 0)
      {
          normalize = 1;
  
      } else if (name->len == sizeof("Accept-Encoding") - 1
          && ngx_strncasecmp(name->data, (u_char *) "Accept-Encoding",
                             sizeof("Accept-Encoding") - 1) == 0)
      {
          normalize = 1;
  
      } else if (name->len == sizeof("Accept-Language") - 1
          && ngx_strncasecmp(name->data, (u_char *) "Accept-Language",
                             sizeof("Accept-Language") - 1) == 0)
      {
          normalize = 1;
      }
  
      part = &r->headers_in.headers.part;
      header = part->elts;
  
      for (i = 0; /* void */ ; i++) {
  
          if (i >= part->nelts) {
              if (part->next == NULL) {
                  break;
              }
  
              part = part->next;
              header = part->elts;
              i = 0;
          }
  
          if (header[i].hash == 0) {
              continue;
          }
  
          if (header[i].key.len != name->len) {
              continue;
          }
  
          if (ngx_strncasecmp(header[i].key.data, name->data, name->len) != 0) {
              continue;
          }
  
          if (!normalize) {
  
              if (multiple) {
                  ngx_md5_update(md5, (u_char *) ",", sizeof(",") - 1);
              }
  
              ngx_md5_update(md5, header[i].value.data, header[i].value.len);
  
              multiple = 1;
  
              continue;
          }
  
          /* normalize spaces */
  
          p = header[i].value.data;
          last = p + header[i].value.len;
  
          while (p < last) {
  
              while (p < last && (*p == ' ' || *p == ',')) { p++; }
  
              start = p;
  
              while (p < last && *p != ',' && *p != ' ') { p++; }
  
              len = p - start;
  
              if (len == 0) {
                  break;
              }
  
              if (multiple) {
                  ngx_md5_update(md5, (u_char *) ",", sizeof(",") - 1);
              }
  
              ngx_md5_update(md5, start, len);
  
              multiple = 1;
          }
      }
  }
  
  
  static ngx_int_t
  ngx_http_file_cache_reopen(ngx_http_request_t *r, ngx_http_cache_t *c)
  {
      ngx_http_file_cache_t  *cache;
  
      ngx_log_debug0(NGX_LOG_DEBUG_HTTP, c->file.log, 0,
                     "http file cache reopen");
  
      if (c->secondary) {
          ngx_log_error(NGX_LOG_CRIT, r->connection->log, 0,
                        "cache file \"%s\" has incorrect vary hash",
                        c->file.name.data);
          return NGX_DECLINED;
      }
  
      cache = c->file_cache;
  
      ngx_shmtx_lock(&cache->shpool->mutex);
  
      c->node->count--;
      c->node = NULL;
  
      ngx_shmtx_unlock(&cache->shpool->mutex);
  
      c->secondary = 1;
      c->file.name.len = 0;
      c->body_start = c->buf->end - c->buf->start;
  
      ngx_memcpy(c->key, c->variant, NGX_HTTP_CACHE_KEY_LEN);
  
      return ngx_http_file_cache_open(r);
  }
  
  
  ngx_int_t
  ngx_http_file_cache_set_header(ngx_http_request_t *r, u_char *buf)
  {
      ngx_http_file_cache_header_t  *h = (ngx_http_file_cache_header_t *) buf;
  
      u_char            *p;
      ngx_str_t         *key;
      ngx_uint_t         i;
      ngx_http_cache_t  *c;
  
      ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                     "http file cache set header");
  
      c = r->cache;
  
      ngx_memzero(h, sizeof(ngx_http_file_cache_header_t));
  
      h->version = NGX_HTTP_CACHE_VERSION;
      h->valid_sec = c->valid_sec;
      h->last_modified = c->last_modified;
      h->date = c->date;
      h->crc32 = c->crc32;
      h->valid_msec = (u_short) c->valid_msec;
      h->header_start = (u_short) c->header_start;
      h->body_start = (u_short) c->body_start;
  
      if (c->etag.len <= NGX_HTTP_CACHE_ETAG_LEN) {
          h->etag_len = (u_char) c->etag.len;
          ngx_memcpy(h->etag, c->etag.data, c->etag.len);
      }
  
      if (c->vary.len) {
          if (c->vary.len > NGX_HTTP_CACHE_VARY_LEN) {
              /* should not happen */
              c->vary.len = NGX_HTTP_CACHE_VARY_LEN;
          }
  
          h->vary_len = (u_char) c->vary.len;
          ngx_memcpy(h->vary, c->vary.data, c->vary.len);
  
          ngx_http_file_cache_vary(r, c->vary.data, c->vary.len, c->variant);
          ngx_memcpy(h->variant, c->variant, NGX_HTTP_CACHE_KEY_LEN);
      }
  
      if (ngx_http_file_cache_update_variant(r, c) != NGX_OK) {
          return NGX_ERROR;
      }
  
      p = buf + sizeof(ngx_http_file_cache_header_t);
  
      p = ngx_cpymem(p, ngx_http_file_cache_key, sizeof(ngx_http_file_cache_key));
  
      key = c->keys.elts;
      for (i = 0; i < c->keys.nelts; i++) {
          p = ngx_copy(p, key[i].data, key[i].len);
      }
  
      *p = LF;
  
      return NGX_OK;
  }
  
  
  static ngx_int_t
  ngx_http_file_cache_update_variant(ngx_http_request_t *r, ngx_http_cache_t *c)
  {
      ngx_http_file_cache_t  *cache;
  
      if (!c->secondary) {
          return NGX_OK;
      }
  
      if (c->vary.len
          && ngx_memcmp(c->variant, c->key, NGX_HTTP_CACHE_KEY_LEN) == 0)
      {
          return NGX_OK;
      }
  
      /*
       * if the variant hash doesn't match one we used as a secondary
       * cache key, switch back to the original key
       */
  
      cache = c->file_cache;
  
      ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                     "http file cache main key");
  
      ngx_shmtx_lock(&cache->shpool->mutex);
  
      c->node->count--;
      c->node->updating = 0;
      c->node = NULL;
  
      ngx_shmtx_unlock(&cache->shpool->mutex);
  
      c->file.name.len = 0;
  
      ngx_memcpy(c->key, c->main, NGX_HTTP_CACHE_KEY_LEN);
  
      if (ngx_http_file_cache_exists(cache, c) == NGX_ERROR) {
          return NGX_ERROR;
      }
  
      if (ngx_http_file_cache_name(r, cache->path) != NGX_OK) {
          return NGX_ERROR;
      }
  
      return NGX_OK;
  }
  
  
  void
  ngx_http_file_cache_update(ngx_http_request_t *r, ngx_temp_file_t *tf)
  {
      off_t                   fs_size;
      ngx_int_t               rc;
      ngx_file_uniq_t         uniq;
      ngx_file_info_t         fi;
      ngx_http_cache_t        *c;
      ngx_ext_rename_file_t   ext;
      ngx_http_file_cache_t  *cache;
  
      c = r->cache;
  
      if (c->updated) {
          return;
      }
  
      ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                     "http file cache update");
  
      cache = c->file_cache;
  
      c->updated = 1;
      c->updating = 0;
  
      uniq = 0;
      fs_size = 0;
  
      ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                     "http file cache rename: \"%s\" to \"%s\"",
                     tf->file.name.data, c->file.name.data);
  
      ext.access = NGX_FILE_OWNER_ACCESS;
      ext.path_access = NGX_FILE_OWNER_ACCESS;
      ext.time = -1;
      ext.create_path = 1;
      ext.delete_file = 1;
      ext.log = r->connection->log;
  
      rc = ngx_ext_rename_file(&tf->file.name, &c->file.name, &ext);
  
      if (rc == NGX_OK) {
  
          if (ngx_fd_info(tf->file.fd, &fi) == NGX_FILE_ERROR) {
              ngx_log_error(NGX_LOG_CRIT, r->connection->log, ngx_errno,
                            ngx_fd_info_n " \"%s\" failed", tf->file.name.data);
  
              rc = NGX_ERROR;
  
          } else {
              uniq = ngx_file_uniq(&fi);
              fs_size = (ngx_file_fs_size(&fi) + cache->bsize - 1) / cache->bsize;
          }
      }
  
      ngx_shmtx_lock(&cache->shpool->mutex);
  
      c->node->count--;
      c->node->uniq = uniq;
      c->node->body_start = c->body_start;
  
      cache->sh->size += fs_size - c->node->fs_size;
      c->node->fs_size = fs_size;
  
      if (rc == NGX_OK) {
          c->node->exists = 1;
      }
  
      c->node->updating = 0;
  
      ngx_shmtx_unlock(&cache->shpool->mutex);
  }
  
  
  void
  ngx_http_file_cache_update_header(ngx_http_request_t *r)
  {
      ssize_t                        n;
      ngx_err_t                      err;
      ngx_file_t                     file;
      ngx_file_info_t                fi;
      ngx_http_cache_t              *c;
      ngx_http_file_cache_header_t   h;
  
      ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                     "http file cache update header");
  
      c = r->cache;
  
      ngx_memzero(&file, sizeof(ngx_file_t));
  
      file.name = c->file.name;
      file.log = r->connection->log;
      file.fd = ngx_open_file(file.name.data, NGX_FILE_RDWR, NGX_FILE_OPEN, 0);
  
      if (file.fd == NGX_INVALID_FILE) {
          err = ngx_errno;
  
          /* cache file may have been deleted */
  
          if (err == NGX_ENOENT) {
              ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                             "http file cache \"%s\" not found",
                             file.name.data);
              return;
          }
  
          ngx_log_error(NGX_LOG_CRIT, r->connection->log, err,
                        ngx_open_file_n " \"%s\" failed", file.name.data);
          return;
      }
  
      /*
       * make sure cache file wasn't replaced;
       * if it was, do nothing
       */
  
      if (ngx_fd_info(file.fd, &fi) == NGX_FILE_ERROR) {
          ngx_log_error(NGX_LOG_CRIT, r->connection->log, ngx_errno,
                        ngx_fd_info_n " \"%s\" failed", file.name.data);
          goto done;
      }
  
      if (c->uniq != ngx_file_uniq(&fi)
          || c->length != ngx_file_size(&fi))
      {
          ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                         "http file cache \"%s\" changed",
                         file.name.data);
          goto done;
      }
  
      n = ngx_read_file(&file, (u_char *) &h,
                        sizeof(ngx_http_file_cache_header_t), 0);
  
      if (n == NGX_ERROR) {
          goto done;
      }
  
      if ((size_t) n != sizeof(ngx_http_file_cache_header_t)) {
          ngx_log_error(NGX_LOG_CRIT, r->connection->log, 0,
                        ngx_read_file_n " read only %z of %z from \"%s\"",
                        n, sizeof(ngx_http_file_cache_header_t), file.name.data);
          goto done;
      }
  
      if (h.version != NGX_HTTP_CACHE_VERSION
          || h.last_modified != c->last_modified
          || h.crc32 != c->crc32
          || h.header_start != c->header_start
          || h.body_start != c->body_start)
      {
          ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                         "http file cache \"%s\" content changed",
                         file.name.data);
          goto done;
      }
  
      /*
       * update cache file header with new data,
       * notably h.valid_sec and h.date
       */
  
      ngx_memzero(&h, sizeof(ngx_http_file_cache_header_t));
  
      h.version = NGX_HTTP_CACHE_VERSION;
      h.valid_sec = c->valid_sec;
      h.last_modified = c->last_modified;
      h.date = c->date;
      h.crc32 = c->crc32;
      h.valid_msec = (u_short) c->valid_msec;
      h.header_start = (u_short) c->header_start;
      h.body_start = (u_short) c->body_start;
  
      if (c->etag.len <= NGX_HTTP_CACHE_ETAG_LEN) {
          h.etag_len = (u_char) c->etag.len;
          ngx_memcpy(h.etag, c->etag.data, c->etag.len);
      }
  
      if (c->vary.len) {
          if (c->vary.len > NGX_HTTP_CACHE_VARY_LEN) {
              /* should not happen */
              c->vary.len = NGX_HTTP_CACHE_VARY_LEN;
          }
  
          h.vary_len = (u_char) c->vary.len;
          ngx_memcpy(h.vary, c->vary.data, c->vary.len);
  
          ngx_http_file_cache_vary(r, c->vary.data, c->vary.len, c->variant);
          ngx_memcpy(h.variant, c->variant, NGX_HTTP_CACHE_KEY_LEN);
      }
  
      (void) ngx_write_file(&file, (u_char *) &h,
                            sizeof(ngx_http_file_cache_header_t), 0);
  
  done:
  
      if (ngx_close_file(file.fd) == NGX_FILE_ERROR) {
          ngx_log_error(NGX_LOG_ALERT, r->connection->log, ngx_errno,
                        ngx_close_file_n " \"%s\" failed", file.name.data);
      }
  }
  
  
  ngx_int_t
  ngx_http_cache_send(ngx_http_request_t *r)
  {
      ngx_int_t          rc;
      ngx_buf_t         *b;
      ngx_chain_t        out;
      ngx_http_cache_t  *c;
  
      c = r->cache;
  
      ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                     "http file cache send: %s", c->file.name.data);
  
      if (r != r->main && c->length - c->body_start == 0) {
          return ngx_http_send_header(r);
      }
  
      /* we need to allocate all before the header would be sent */
  
      b = ngx_pcalloc(r->pool, sizeof(ngx_buf_t));
      if (b == NULL) {
          return NGX_HTTP_INTERNAL_SERVER_ERROR;
      }
  
      b->file = ngx_pcalloc(r->pool, sizeof(ngx_file_t));
      if (b->file == NULL) {
          return NGX_HTTP_INTERNAL_SERVER_ERROR;
      }
  
      rc = ngx_http_send_header(r);
  
      if (rc == NGX_ERROR || rc > NGX_OK || r->header_only) {
          return rc;
      }
  
      b->file_pos = c->body_start;
      b->file_last = c->length;
  
      b->in_file = (c->length - c->body_start) ? 1: 0;
      b->last_buf = (r == r->main) ? 1: 0;
      b->last_in_chain = 1;
  
      b->file->fd = c->file.fd;
      b->file->name = c->file.name;
      b->file->log = r->connection->log;
  
      out.buf = b;
      out.next = NULL;
  
      return ngx_http_output_filter(r, &out);
  }
  
  
  void
  ngx_http_file_cache_free(ngx_http_cache_t *c, ngx_temp_file_t *tf)
  {
      ngx_http_file_cache_t       *cache;
      ngx_http_file_cache_node_t  *fcn;
  
      if (c->updated || c->node == NULL) {
          return;
      }
  
      cache = c->file_cache;
  
      ngx_log_debug1(NGX_LOG_DEBUG_HTTP, c->file.log, 0,
                     "http file cache free, fd: %d", c->file.fd);
  
      ngx_shmtx_lock(&cache->shpool->mutex);
  
      fcn = c->node;
      fcn->count--;
  
      if (c->updating && fcn->lock_time == c->lock_time) {
          fcn->updating = 0;
      }
  
      if (c->error) {
          fcn->error = c->error;
  
          if (c->valid_sec) {
              fcn->valid_sec = c->valid_sec;
              fcn->valid_msec = c->valid_msec;
          }
  
      } else if (!fcn->exists && fcn->count == 0 && c->min_uses == 1) {
          ngx_queue_remove(&fcn->queue);
          ngx_rbtree_delete(&cache->sh->rbtree, &fcn->node);
          ngx_slab_free_locked(cache->shpool, fcn);
          cache->sh->count--;
          c->node = NULL;
      }
  
      ngx_shmtx_unlock(&cache->shpool->mutex);
  
      c->updated = 1;
      c->updating = 0;
  
      if (c->temp_file) {
          if (tf && tf->file.fd != NGX_INVALID_FILE) {
              ngx_log_debug1(NGX_LOG_DEBUG_HTTP, c->file.log, 0,
                             "http file cache incomplete: \"%s\"",
                             tf->file.name.data);
  
              if (ngx_delete_file(tf->file.name.data) == NGX_FILE_ERROR) {
                  ngx_log_error(NGX_LOG_CRIT, c->file.log, ngx_errno,
                                ngx_delete_file_n " \"%s\" failed",
                                tf->file.name.data);
              }
          }
      }
  
      if (c->wait_event.timer_set) {
          ngx_del_timer(&c->wait_event);
      }
  }
  
  
  static void
  ngx_http_file_cache_cleanup(void *data)
  {
      ngx_http_cache_t  *c = data;
  
      if (c->updated) {
          return;
      }
  
      ngx_log_debug0(NGX_LOG_DEBUG_HTTP, c->file.log, 0,
                     "http file cache cleanup");
  
      if (c->updating) {
          ngx_log_error(NGX_LOG_ALERT, c->file.log, 0,
                        "stalled cache updating, error:%ui", c->error);
      }
  
      ngx_http_file_cache_free(c, NULL);
  }
  
  
  static time_t
  ngx_http_file_cache_forced_expire(ngx_http_file_cache_t *cache)
  {
      u_char                      *name;
      size_t                       len;
      time_t                       wait;
      ngx_uint_t                   tries;
      ngx_path_t                  *path;
      ngx_queue_t                 *q;
      ngx_http_file_cache_node_t  *fcn;
  
      ngx_log_debug0(NGX_LOG_DEBUG_HTTP, ngx_cycle->log, 0,
                     "http file cache forced expire");
  
      path = cache->path;
      len = path->name.len + 1 + path->len + 2 * NGX_HTTP_CACHE_KEY_LEN;
  
      name = ngx_alloc(len + 1, ngx_cycle->log);
      if (name == NULL) {
          return 10;
      }
  
      ngx_memcpy(name, path->name.data, path->name.len);
  
      wait = 10;
      tries = 20;
  
      ngx_shmtx_lock(&cache->shpool->mutex);
  
      for (q = ngx_queue_last(&cache->sh->queue);
           q != ngx_queue_sentinel(&cache->sh->queue);
           q = ngx_queue_prev(q))
      {
          fcn = ngx_queue_data(q, ngx_http_file_cache_node_t, queue);
  
          ngx_log_debug6(NGX_LOG_DEBUG_HTTP, ngx_cycle->log, 0,
                    "http file cache forced expire: #%d %d %02xd%02xd%02xd%02xd",
                    fcn->count, fcn->exists,
                    fcn->key[0], fcn->key[1], fcn->key[2], fcn->key[3]);
  
          if (fcn->count == 0) {
              ngx_http_file_cache_delete(cache, q, name);
              wait = 0;
  
          } else {
              if (--tries) {
                  continue;
              }
  
              wait = 1;
          }
  
          break;
      }
  
      ngx_shmtx_unlock(&cache->shpool->mutex);
  
      ngx_free(name);
  
      return wait;
  }
  
  
  static time_t
  ngx_http_file_cache_expire(ngx_http_file_cache_t *cache)
  {
      u_char                      *name, *p;
      size_t                       len;
      time_t                       now, wait;
      ngx_path_t                  *path;
      ngx_queue_t                 *q;
      ngx_http_file_cache_node_t  *fcn;
      u_char                       key[2 * NGX_HTTP_CACHE_KEY_LEN];
  
      ngx_log_debug0(NGX_LOG_DEBUG_HTTP, ngx_cycle->log, 0,
                     "http file cache expire");
  
      path = cache->path;
      len = path->name.len + 1 + path->len + 2 * NGX_HTTP_CACHE_KEY_LEN;
  
      name = ngx_alloc(len + 1, ngx_cycle->log);
      if (name == NULL) {
          return 10;
      }
  
      ngx_memcpy(name, path->name.data, path->name.len);
  
      now = ngx_time();
  
      ngx_shmtx_lock(&cache->shpool->mutex);
  
      for ( ;; ) {
  
          if (ngx_quit || ngx_terminate) {
              wait = 1;
              break;
          }
  
          if (ngx_queue_empty(&cache->sh->queue)) {
              wait = 10;
              break;
          }
  
          q = ngx_queue_last(&cache->sh->queue);
  
          fcn = ngx_queue_data(q, ngx_http_file_cache_node_t, queue);
  
          wait = fcn->expire - now;
  
          if (wait > 0) {
              wait = wait > 10 ? 10 : wait;
              break;
          }
  
          ngx_log_debug6(NGX_LOG_DEBUG_HTTP, ngx_cycle->log, 0,
                         "http file cache expire: #%d %d %02xd%02xd%02xd%02xd",
                         fcn->count, fcn->exists,
                         fcn->key[0], fcn->key[1], fcn->key[2], fcn->key[3]);
  
          if (fcn->count == 0) {
              ngx_http_file_cache_delete(cache, q, name);
              continue;
          }
  
          if (fcn->deleting) {
              wait = 1;
              break;
          }
  
          p = ngx_hex_dump(key, (u_char *) &fcn->node.key,
                           sizeof(ngx_rbtree_key_t));
          len = NGX_HTTP_CACHE_KEY_LEN - sizeof(ngx_rbtree_key_t);
          (void) ngx_hex_dump(p, fcn->key, len);
  
          /*
           * abnormally exited workers may leave locked cache entries,
           * and although it may be safe to remove them completely,
           * we prefer to just move them to the top of the inactive queue
           */
  
          ngx_queue_remove(q);
          fcn->expire = ngx_time() + cache->inactive;
          ngx_queue_insert_head(&cache->sh->queue, &fcn->queue);
  
          ngx_log_error(NGX_LOG_ALERT, ngx_cycle->log, 0,
                        "ignore long locked inactive cache entry %*s, count:%d",
                        2 * NGX_HTTP_CACHE_KEY_LEN, key, fcn->count);
      }
  
      ngx_shmtx_unlock(&cache->shpool->mutex);
  
      ngx_free(name);
  
      return wait;
  }
  
  
  static void
  ngx_http_file_cache_delete(ngx_http_file_cache_t *cache, ngx_queue_t *q,
      u_char *name)
  {
      u_char                      *p;
      size_t                       len;
      ngx_path_t                  *path;
      ngx_http_file_cache_node_t  *fcn;
  
      fcn = ngx_queue_data(q, ngx_http_file_cache_node_t, queue);
  
      if (fcn->exists) {
          cache->sh->size -= fcn->fs_size;
  
          path = cache->path;
          p = name + path->name.len + 1 + path->len;
          p = ngx_hex_dump(p, (u_char *) &fcn->node.key,
                           sizeof(ngx_rbtree_key_t));
          len = NGX_HTTP_CACHE_KEY_LEN - sizeof(ngx_rbtree_key_t);
          p = ngx_hex_dump(p, fcn->key, len);
          *p = '\0';
  
          fcn->count++;
          fcn->deleting = 1;
          ngx_shmtx_unlock(&cache->shpool->mutex);
  
          len = path->name.len + 1 + path->len + 2 * NGX_HTTP_CACHE_KEY_LEN;
          ngx_create_hashed_filename(path, name, len);
  
          ngx_log_debug1(NGX_LOG_DEBUG_HTTP, ngx_cycle->log, 0,
                         "http file cache expire: \"%s\"", name);
  
          if (ngx_delete_file(name) == NGX_FILE_ERROR) {
              ngx_log_error(NGX_LOG_CRIT, ngx_cycle->log, ngx_errno,
                            ngx_delete_file_n " \"%s\" failed", name);
          }
  
          ngx_shmtx_lock(&cache->shpool->mutex);
          fcn->count--;
          fcn->deleting = 0;
      }
  
      if (fcn->count == 0) {
          ngx_queue_remove(q);
          ngx_rbtree_delete(&cache->sh->rbtree, &fcn->node);
          ngx_slab_free_locked(cache->shpool, fcn);
          cache->sh->count--;
      }
  }
  
  
  static time_t
  ngx_http_file_cache_manager(void *data)
  {
      ngx_http_file_cache_t  *cache = data;
  
      off_t       size;
      time_t      next, wait;
      ngx_uint_t  count, watermark;
  
      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;
          count = cache->sh->count;
          watermark = cache->sh->watermark;
  
          ngx_shmtx_unlock(&cache->shpool->mutex);
  
          ngx_log_debug3(NGX_LOG_DEBUG_HTTP, ngx_cycle->log, 0,
                         "http file cache size: %O c:%ui w:%i",
                         size, count, (ngx_int_t) watermark);
  
          if (size < cache->max_size && count < watermark) {
              return next;
          }
  
          wait = ngx_http_file_cache_forced_expire(cache);
  
          if (wait > 0) {
              return wait;
          }
  
          if (ngx_quit || ngx_terminate) {
              return next;
          }
      }
  }
  
  
  static void
  ngx_http_file_cache_loader(void *data)
  {
      ngx_http_file_cache_t  *cache = data;
  
      ngx_tree_ctx_t  tree;
  
      if (!cache->sh->cold || cache->sh->loading) {
          return;
      }
  
      if (!ngx_atomic_cmp_set(&cache->sh->loading, 0, ngx_pid)) {
          return;
      }
  
      ngx_log_debug0(NGX_LOG_DEBUG_HTTP, ngx_cycle->log, 0,
                     "http file cache loader");
  
      tree.init_handler = NULL;
      tree.file_handler = ngx_http_file_cache_manage_file;
      tree.pre_tree_handler = ngx_http_file_cache_manage_directory;
      tree.post_tree_handler = ngx_http_file_cache_noop;
      tree.spec_handler = ngx_http_file_cache_delete_file;
      tree.data = cache;
      tree.alloc = 0;
      tree.log = ngx_cycle->log;
  
      cache->last = ngx_current_msec;
      cache->files = 0;
  
      if (ngx_walk_tree(&tree, &cache->path->name) == NGX_ABORT) {
          cache->sh->loading = 0;
          return;
      }
  
      cache->sh->cold = 0;
      cache->sh->loading = 0;
  
      ngx_log_error(NGX_LOG_NOTICE, ngx_cycle->log, 0,
                    "http file cache: %V %.3fM, bsize: %uz",
                    &cache->path->name,
                    ((double) cache->sh->size * cache->bsize) / (1024 * 1024),
                    cache->bsize);
  }
  
  
  static ngx_int_t
  ngx_http_file_cache_noop(ngx_tree_ctx_t *ctx, ngx_str_t *path)
  {
      return NGX_OK;
  }
  
  
  static ngx_int_t
  ngx_http_file_cache_manage_file(ngx_tree_ctx_t *ctx, ngx_str_t *path)
  {
      ngx_msec_t              elapsed;
      ngx_http_file_cache_t  *cache;
  
      cache = ctx->data;
  
      if (ngx_http_file_cache_add_file(ctx, path) != NGX_OK) {
          (void) ngx_http_file_cache_delete_file(ctx, path);
      }
  
      if (++cache->files >= cache->loader_files) {
          ngx_http_file_cache_loader_sleep(cache);
  
      } else {
          ngx_time_update();
  
          elapsed = ngx_abs((ngx_msec_int_t) (ngx_current_msec - cache->last));
  
          ngx_log_debug1(NGX_LOG_DEBUG_HTTP, ngx_cycle->log, 0,
                         "http file cache loader time elapsed: %M", elapsed);
  
          if (elapsed >= cache->loader_threshold) {
              ngx_http_file_cache_loader_sleep(cache);
          }
      }
  
      return (ngx_quit || ngx_terminate) ? NGX_ABORT : NGX_OK;
  }
  
  
  static ngx_int_t
  ngx_http_file_cache_manage_directory(ngx_tree_ctx_t *ctx, ngx_str_t *path)
  {
      if (path->len >= 5
          && ngx_strncmp(path->data + path->len - 5, "/temp", 5) == 0)
      {
          return NGX_DECLINED;
      }
  
      return NGX_OK;
  }
  
  
  static void
  ngx_http_file_cache_loader_sleep(ngx_http_file_cache_t *cache)
  {
      ngx_msleep(cache->loader_sleep);
  
      ngx_time_update();
  
      cache->last = ngx_current_msec;
      cache->files = 0;
  }
  
  
  static ngx_int_t
  ngx_http_file_cache_add_file(ngx_tree_ctx_t *ctx, ngx_str_t *name)
  {
      u_char                 *p;
      ngx_int_t               n;
      ngx_uint_t              i;
      ngx_http_cache_t        c;
      ngx_http_file_cache_t  *cache;
  
      if (name->len < 2 * NGX_HTTP_CACHE_KEY_LEN) {
          return NGX_ERROR;
      }
  
      if (ctx->size < (off_t) sizeof(ngx_http_file_cache_header_t)) {
          ngx_log_error(NGX_LOG_CRIT, ctx->log, 0,
                        "cache file \"%s\" is too small", name->data);
          return NGX_ERROR;
      }
  
      ngx_memzero(&c, sizeof(ngx_http_cache_t));
      cache = ctx->data;
  
      c.length = ctx->size;
      c.fs_size = (ctx->fs_size + cache->bsize - 1) / cache->bsize;
  
      p = &name->data[name->len - 2 * NGX_HTTP_CACHE_KEY_LEN];
  
      for (i = 0; i < NGX_HTTP_CACHE_KEY_LEN; i++) {
          n = ngx_hextoi(p, 2);
  
          if (n == NGX_ERROR) {
              return NGX_ERROR;
          }
  
          p += 2;
  
          c.key[i] = (u_char) n;
      }
  
      return ngx_http_file_cache_add(cache, &c);
  }
  
  
  static ngx_int_t
  ngx_http_file_cache_add(ngx_http_file_cache_t *cache, ngx_http_cache_t *c)
  {
      ngx_http_file_cache_node_t  *fcn;
  
      ngx_shmtx_lock(&cache->shpool->mutex);
  
      fcn = ngx_http_file_cache_lookup(cache, c->key);
  
      if (fcn == NULL) {
  
          fcn = ngx_slab_calloc_locked(cache->shpool,
                                       sizeof(ngx_http_file_cache_node_t));
          if (fcn == NULL) {
              ngx_http_file_cache_set_watermark(cache);
  
              if (cache->fail_time != ngx_time()) {
                  cache->fail_time = ngx_time();
                  ngx_log_error(NGX_LOG_ALERT, ngx_cycle->log, 0,
                             "could not allocate node%s", cache->shpool->log_ctx);
              }
  
              ngx_shmtx_unlock(&cache->shpool->mutex);
              return NGX_ERROR;
          }
  
          cache->sh->count++;
  
          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);
  
          fcn->uses = 1;
          fcn->exists = 1;
          fcn->fs_size = c->fs_size;
  
          cache->sh->size += c->fs_size;
  
      } else {
          ngx_queue_remove(&fcn->queue);
      }
  
      fcn->expire = ngx_time() + cache->inactive;
  
      ngx_queue_insert_head(&cache->sh->queue, &fcn->queue);
  
      ngx_shmtx_unlock(&cache->shpool->mutex);
  
      return NGX_OK;
  }
  
  
  static ngx_int_t
  ngx_http_file_cache_delete_file(ngx_tree_ctx_t *ctx, ngx_str_t *path)
  {
      ngx_log_debug1(NGX_LOG_DEBUG_HTTP, ctx->log, 0,
                     "http file cache delete: \"%s\"", path->data);
  
      if (ngx_delete_file(path->data) == NGX_FILE_ERROR) {
          ngx_log_error(NGX_LOG_CRIT, ctx->log, ngx_errno,
                        ngx_delete_file_n " \"%s\" failed", path->data);
      }
  
      return NGX_OK;
  }
  
  
  static void
  ngx_http_file_cache_set_watermark(ngx_http_file_cache_t *cache)
  {
      cache->sh->watermark = cache->sh->count - cache->sh->count / 8;
  
      ngx_log_debug1(NGX_LOG_DEBUG_HTTP, ngx_cycle->log, 0,
                     "http file cache watermark: %ui", cache->sh->watermark);
  }
  
  
  time_t
  ngx_http_file_cache_valid(ngx_array_t *cache_valid, ngx_uint_t status)
  {
      ngx_uint_t               i;
      ngx_http_cache_valid_t  *valid;
  
      if (cache_valid == NULL) {
          return 0;
      }
  
      valid = cache_valid->elts;
      for (i = 0; i < cache_valid->nelts; i++) {
  
          if (valid[i].status == 0) {
              return valid[i].valid;
          }
  
          if (valid[i].status == status) {
              return valid[i].valid;
          }
      }
  
      return 0;
  }
  
  
  char *
  ngx_http_file_cache_set_slot(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
  {
      char  *confp = conf;
  
      off_t                   max_size;
      u_char                 *last, *p;
      time_t                  inactive;
      size_t                  len;
      ssize_t                 size;
      ngx_str_t               s, name, *value;
      ngx_int_t               loader_files;
      ngx_msec_t              loader_sleep, loader_threshold;
      ngx_uint_t              i, n, use_temp_path;
      ngx_array_t            *caches;
      ngx_http_file_cache_t  *cache, **ce;
  
      cache = ngx_pcalloc(cf->pool, sizeof(ngx_http_file_cache_t));
      if (cache == NULL) {
          return NGX_CONF_ERROR;
      }
  
      cache->path = ngx_pcalloc(cf->pool, sizeof(ngx_path_t));
      if (cache->path == NULL) {
          return NGX_CONF_ERROR;
      }
  
      use_temp_path = 1;
  
      inactive = 600;
      loader_files = 100;
      loader_sleep = 50;
      loader_threshold = 200;
  
      name.len = 0;
      size = 0;
      max_size = NGX_MAX_OFF_T_VALUE;
  
      value = cf->args->elts;
  
      cache->path->name = value[1];
  
      if (cache->path->name.data[cache->path->name.len - 1] == '/') {
          cache->path->name.len--;
      }
  
      if (ngx_conf_full_name(cf->cycle, &cache->path->name, 0) != NGX_OK) {
          return NGX_CONF_ERROR;
      }
  
      for (i = 2; i < cf->args->nelts; i++) {
  
          if (ngx_strncmp(value[i].data, "levels=", 7) == 0) {
  
              p = value[i].data + 7;
              last = value[i].data + value[i].len;
  
              for (n = 0; n < 3 && p < last; n++) {
  
                  if (*p > '0' && *p < '3') {
  
                      cache->path->level[n] = *p++ - '0';
                      cache->path->len += cache->path->level[n] + 1;
  
                      if (p == last) {
                          break;
                      }
  
                      if (*p++ == ':' && n < 2 && p != last) {
                          continue;
                      }
  
                      goto invalid_levels;
                  }
  
                  goto invalid_levels;
              }
  
              if (cache->path->len < 10 + 3) {
                  continue;
              }
  
          invalid_levels:
  
              ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                                 "invalid \"levels\" \"%V\"", &value[i]);
              return NGX_CONF_ERROR;
          }
  
          if (ngx_strncmp(value[i].data, "use_temp_path=", 14) == 0) {
  
              if (ngx_strcmp(&value[i].data[14], "on") == 0) {
                  use_temp_path = 1;
  
              } else if (ngx_strcmp(&value[i].data[14], "off") == 0) {
                  use_temp_path = 0;
  
              } else {
                  ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                                     "invalid use_temp_path value \"%V\", "
                                     "it must be \"on\" or \"off\"",
                                     &value[i]);
                  return NGX_CONF_ERROR;
              }
  
              continue;
          }
  
          if (ngx_strncmp(value[i].data, "keys_zone=", 10) == 0) {
  
              name.data = value[i].data + 10;
  
              p = (u_char *) ngx_strchr(name.data, ':');
  
              if (p) {
                  name.len = p - name.data;
  
                  p++;
  
                  s.len = value[i].data + value[i].len - p;
                  s.data = p;
  
                  size = ngx_parse_size(&s);
                  if (size > 8191) {
                      continue;
                  }
              }
  
              ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                                 "invalid keys zone size \"%V\"", &value[i]);
              return NGX_CONF_ERROR;
          }
  
          if (ngx_strncmp(value[i].data, "inactive=", 9) == 0) {
  
              s.len = value[i].len - 9;
              s.data = value[i].data + 9;
  
              inactive = ngx_parse_time(&s, 1);
              if (inactive == (time_t) NGX_ERROR) {
                  ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                                     "invalid inactive value \"%V\"", &value[i]);
                  return NGX_CONF_ERROR;
              }
  
              continue;
          }
  
          if (ngx_strncmp(value[i].data, "max_size=", 9) == 0) {
  
              s.len = value[i].len - 9;
              s.data = value[i].data + 9;
  
              max_size = ngx_parse_offset(&s);
              if (max_size < 0) {
                  ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                                     "invalid max_size value \"%V\"", &value[i]);
                  return NGX_CONF_ERROR;
              }
  
              continue;
          }
  
          if (ngx_strncmp(value[i].data, "loader_files=", 13) == 0) {
  
              loader_files = ngx_atoi(value[i].data + 13, value[i].len - 13);
              if (loader_files == NGX_ERROR) {
                  ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                             "invalid loader_files value \"%V\"", &value[i]);
                  return NGX_CONF_ERROR;
              }
  
              continue;
          }
  
          if (ngx_strncmp(value[i].data, "loader_sleep=", 13) == 0) {
  
              s.len = value[i].len - 13;
              s.data = value[i].data + 13;
  
              loader_sleep = ngx_parse_time(&s, 0);
              if (loader_sleep == (ngx_msec_t) NGX_ERROR) {
                  ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                             "invalid loader_sleep value \"%V\"", &value[i]);
                  return NGX_CONF_ERROR;
              }
  
              continue;
          }
  
          if (ngx_strncmp(value[i].data, "loader_threshold=", 17) == 0) {
  
              s.len = value[i].len - 17;
              s.data = value[i].data + 17;
  
              loader_threshold = ngx_parse_time(&s, 0);
              if (loader_threshold == (ngx_msec_t) NGX_ERROR) {
                  ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                             "invalid loader_threshold value \"%V\"", &value[i]);
                  return NGX_CONF_ERROR;
              }
  
              continue;
          }
  
          ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                             "invalid parameter \"%V\"", &value[i]);
          return NGX_CONF_ERROR;
      }
  
      if (name.len == 0 || size == 0) {
          ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                             "\"%V\" must have \"keys_zone\" parameter",
                             &cmd->name);
          return NGX_CONF_ERROR;
      }
  
      cache->path->manager = ngx_http_file_cache_manager;
      cache->path->loader = ngx_http_file_cache_loader;
      cache->path->data = cache;
      cache->path->conf_file = cf->conf_file->file.name.data;
      cache->path->line = cf->conf_file->line;
      cache->loader_files = loader_files;
      cache->loader_sleep = loader_sleep;
      cache->loader_threshold = loader_threshold;
  
      if (ngx_add_path(cf, &cache->path) != NGX_OK) {
          return NGX_CONF_ERROR;
      }
  
      if (!use_temp_path) {
          cache->temp_path = ngx_pcalloc(cf->pool, sizeof(ngx_path_t));
          if (cache->temp_path == NULL) {
              return NGX_CONF_ERROR;
          }
  
          len = cache->path->name.len + sizeof("/temp") - 1;
  
          p = ngx_pnalloc(cf->pool, len + 1);
          if (p == NULL) {
              return NGX_CONF_ERROR;
          }
  
          cache->temp_path->name.len = len;
          cache->temp_path->name.data = p;
  
          p = ngx_cpymem(p, cache->path->name.data, cache->path->name.len);
          ngx_memcpy(p, "/temp", sizeof("/temp"));
  
          ngx_memcpy(&cache->temp_path->level, &cache->path->level,
                     3 * sizeof(size_t));
  
          cache->temp_path->len = cache->path->len;
          cache->temp_path->conf_file = cf->conf_file->file.name.data;
          cache->temp_path->line = cf->conf_file->line;
  
          if (ngx_add_path(cf, &cache->temp_path) != NGX_OK) {
              return NGX_CONF_ERROR;
          }
      }
  
      cache->shm_zone = ngx_shared_memory_add(cf, &name, size, cmd->post);
      if (cache->shm_zone == NULL) {
          return NGX_CONF_ERROR;
      }
  
      if (cache->shm_zone->data) {
          ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                             "duplicate zone \"%V\"", &name);
          return NGX_CONF_ERROR;
      }
  
  
      cache->shm_zone->init = ngx_http_file_cache_init;
      cache->shm_zone->data = cache;
  
      cache->inactive = inactive;
      cache->max_size = max_size;
  
      caches = (ngx_array_t *) (confp + cmd->offset);
  
      ce = ngx_array_push(caches);
      if (ce == NULL) {
          return NGX_CONF_ERROR;
      }
  
      *ce = cache;
  
      return NGX_CONF_OK;
  }
  
  
  char *
  ngx_http_file_cache_valid_set_slot(ngx_conf_t *cf, ngx_command_t *cmd,
      void *conf)
  {
      char  *p = conf;
  
      time_t                    valid;
      ngx_str_t                *value;
      ngx_uint_t                i, n, status;
      ngx_array_t             **a;
      ngx_http_cache_valid_t   *v;
      static ngx_uint_t         statuses[] = { 200, 301, 302 };
  
      a = (ngx_array_t **) (p + cmd->offset);
  
      if (*a == NGX_CONF_UNSET_PTR) {
          *a = ngx_array_create(cf->pool, 1, sizeof(ngx_http_cache_valid_t));
          if (*a == NULL) {
              return NGX_CONF_ERROR;
          }
      }
  
      value = cf->args->elts;
      n = cf->args->nelts - 1;
  
      valid = ngx_parse_time(&value[n], 1);
      if (valid == (time_t) NGX_ERROR) {
          ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                             "invalid time value \"%V\"", &value[n]);
          return NGX_CONF_ERROR;
      }
  
      if (n == 1) {
  
          for (i = 0; i < 3; i++) {
              v = ngx_array_push(*a);
              if (v == NULL) {
                  return NGX_CONF_ERROR;
              }
  
              v->status = statuses[i];
              v->valid = valid;
          }
  
          return NGX_CONF_OK;
      }
  
      for (i = 1; i < n; i++) {
  
          if (ngx_strcmp(value[i].data, "any") == 0) {
  
              status = 0;
  
          } else {
  
              status = ngx_atoi(value[i].data, value[i].len);
              if (status < 100) {
                  ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                                     "invalid status \"%V\"", &value[i]);
                  return NGX_CONF_ERROR;
              }
          }
  
          v = ngx_array_push(*a);
          if (v == NULL) {
              return NGX_CONF_ERROR;
          }
  
          v->status = status;
          v->valid = valid;
      }
  
      return NGX_CONF_OK;
  }
  