/*
 * The front door to cgit's page cache. A caller hands over a key identifying
 * the request and a callback that renders the page, and gets back either the
 * copy already on disk or a freshly rendered one.
 */

#ifndef CGIT_CACHE_H
#define CGIT_CACHE_H

typedef void (*cache_fill_fn)(void);

/*
 * Write the page for key to stdout, taking it from the cache when a fresh
 * slot for that key is there and rendering it through fn when it is not. size
 * is how many slots the cache may use and path is the directory holding them.
 * ttl is how many minutes a slot for this key stays fresh, where a negative
 * ttl never expires and a ttl of zero skips the cache for this request.
 * Returns 0 when the page was written, and an errno value when it was not.
 */
extern int cache_process(int size, const char *path, const char *key, int ttl, cache_fill_fn fn);

// Write one line per cache slot to stdout, giving its path, modification
// time, size and key.
extern int cache_ls(const char *path);

/*
 * Give up on the slot being filled, discarding what has been rendered into it
 * and putting stdout back on the client. Anything that ends a request part way
 * through rendering has to call this before it writes what the visitor should
 * see, because until then stdout is the cache file and the visitor is on
 * course to receive nothing at all. Does nothing when no slot is being filled.
 */
extern void cache_abandon_fill(void);

extern unsigned long cache_hash_str(const char *str);

#endif // CGIT_CACHE_H