void *mutt_hcache_fetch(hcache_t *db, const char *filename,
ssize_t (*keylen)(const char *fn));
int mutt_hcache_store(hcache_t *db, const char *filename, HEADER *h,
void *mutt_hcache_fetch(hcache_t *db, const char *filename,
ssize_t (*keylen)(const char *fn));
int mutt_hcache_store(hcache_t *db, const char *filename, HEADER *h,
ssize_t (*keylen)(const char *fn));
int mutt_hcache_delete(hcache_t *db, const char *filename,
ssize_t (*keylen)(const char *fn));
ssize_t (*keylen)(const char *fn));
int mutt_hcache_delete(hcache_t *db, const char *filename,
ssize_t (*keylen)(const char *fn));