#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. Also if message data may have changed,
   imap_msgcache_close() must be called.

   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. 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,
			   ImapCacheField fields, uoff_t virtual_size,
			   uoff_t pv_headers_size, uoff_t pv_body_size,
			   IOBuffer *inbuf,
			   IOBuffer *(*inbuf_rewind)(IOBuffer *inbuf,
						     void *context),
			   void *context);

/* Close the IOBuffer for cached message. */
void imap_msgcache_close(ImapMessageCache *cache);

/* 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 inbuf is not NULL, it's set
   to point to beginning of message, or to beginning of message body if
   hdr_size is NULL. */
int imap_msgcache_get_rfc822(ImapMessageCache *cache, unsigned int uid,
			     MessageSize *hdr_size, MessageSize *body_size,
                             IOBuffer **inbuf);

/* Returns FALSE if message isn't in cache. *inbuf is set to point to the first
   non-skipped character. size is set to specify the full size of message. */
int imap_msgcache_get_rfc822_partial(ImapMessageCache *cache, unsigned int uid,
				     uoff_t virtual_skip,
				     uoff_t max_virtual_size,
				     int get_header, MessageSize *size,
				     IOBuffer **inbuf);

/* Returns FALSE if message isn't in cache.  *inbuf is set to point to
   beginning of message. */
int imap_msgcache_get_data(ImapMessageCache *cache, unsigned int uid,
                           IOBuffer **inbuf);

#endif