#ifndef __IMAP_MESSAGE_CACHE_H
#define __IMAP_MESSAGE_CACHE_H

/* IMAP message cache. Caches are mailbox-specific and must be cleared
   if UID validity changes.

   Caching is mostly done to avoid parsing the same message multiple times
   when client fetches the message in parts.
*/

#include "message-parser.h"

typedef enum {
	IMAP_CACHE_BODY			= 0x01,
	IMAP_CACHE_BODYSTRUCTURE	= 0x02,
	IMAP_CACHE_ENVELOPE		= 0x04,

	IMAP_CACHE_MESSAGE_OPEN		= 0x08,
	IMAP_CACHE_MESSAGE_PART		= 0x10,
	IMAP_CACHE_MESSAGE_HDR_SIZE	= 0x20,
	IMAP_CACHE_MESSAGE_BODY_SIZE	= 0x40
} ImapCacheField;

typedef struct _ImapMessageCache ImapMessageCache;

ImapMessageCache *imap_msgcache_alloc(void);
void imap_msgcache_clear(ImapMessageCache *cache);
void imap_msgcache_free(ImapMessageCache *cache);

/* Returns TRUE if all given fields are fully cached, or at least the
   message is open (ie. you don't need imap_msgcache_message()). */
int imap_msgcache_is_cached(ImapMessageCache *cache, unsigned int uid,
			    ImapCacheField fields);

/* Parse and cache the message. The given file handle is automatically
   closed by cache and must not be closed elsewhere. If pv_headers_size
   and pv_body_size is non-zero, they're set to saved to message's both
   physical and virtual sizes (ie. doesn't need to be calculated). */
void imap_msgcache_message(ImapMessageCache *cache, unsigned int uid,
			   int fd, off_t offset, size_t size,
			   size_t virtual_size, size_t pv_headers_size,
			   size_t pv_body_size, ImapCacheField fields);

/* Store a value for field in cache */
void imap_msgcache_set(ImapMessageCache *cache, unsigned int uid,
		       ImapCacheField field, const char *value);

/* Returns the field from cache, or NULL if it's not cached. */
const char *imap_msgcache_get(ImapMessageCache *cache, unsigned int uid,
			      ImapCacheField field);

/* Returns the root MessagePart for message, or NULL if it's not cached. */
MessagePart *imap_msgcache_get_parts(ImapMessageCache *cache, unsigned int uid);

/* Returns FALSE if message isn't in cache. If data is not NULL, it's set to
   point to beginning of message data. If fd is not NULL, it's set to contain
   the message file descriptor seeked to same position as *data. If hdr_size
   is NULL, *data contains only the message body. */
int imap_msgcache_get_rfc822(ImapMessageCache *cache, unsigned int uid,
			     MessageSize *hdr_size, MessageSize *body_size,
			     const char **data, int *fd);

/* Returns FALSE if message isn't in cache. *data is set to point to the first
   non-skipped character. size is set to specify the real size for message. */
int imap_msgcache_get_rfc822_partial(ImapMessageCache *cache, unsigned int uid,
				     off_t virtual_skip,
				     size_t max_virtual_size,
				     int get_header, MessageSize *size,
				     const char **data, int *fd);

/* Like imap_msgcache_get_rfc822() without calculating virtual sizes.
   size and fd may be NULL. */
int imap_msgcache_get_data(ImapMessageCache *cache, unsigned int uid,
			   const char **data, int *fd, size_t *size);

#endif