mail-index.h revision 025961fd171e7be79d7be7dee3d619de317f0b1e
#ifndef __MAIL_INDEX_H
#define __MAIL_INDEX_H
#include "message-parser.h"
#include "imap-util.h"
#define MAIL_INDEX_VERSION 1
#define INDEX_FILE_PREFIX ".imap.index"
enum {
};
enum {
/* Rebuild flag is set while index is being rebuilt or when
some error is noticed in the index file. If this flag is set,
the index shouldn't be used before rebuilding it. */
MAIL_INDEX_FLAG_REBUILD = 0x01,
MAIL_INDEX_FLAG_FSCK = 0x02,
MAIL_INDEX_FLAG_CACHE_FIELDS = 0x04,
MAIL_INDEX_FLAG_COMPRESS = 0x08,
MAIL_INDEX_FLAG_COMPRESS_DATA = 0x10,
MAIL_INDEX_FLAG_REBUILD_TREE = 0x20,
MAIL_INDEX_FLAG_DIRTY_MESSAGES = 0x40,
};
typedef enum {
FIELD_TYPE_LOCATION = 0x0001,
FIELD_TYPE_ENVELOPE = 0x0002,
FIELD_TYPE_BODY = 0x0004,
FIELD_TYPE_BODYSTRUCTURE = 0x0008,
FIELD_TYPE_MD5 = 0x0010,
FIELD_TYPE_MESSAGEPART = 0x0020,
FIELD_TYPE_LAST = 0x0040,
} MailField;
typedef enum {
/* If binary flags are set, it's not checked whether mail is
missing CRs. So this flag may be set as an optimization for
regular non-binary mails as well if it's known that it contains
valid CR+LF line breaks. */
INDEX_MAIL_FLAG_BINARY_HEADER = 0x0001,
INDEX_MAIL_FLAG_BINARY_BODY = 0x0002,
/* Currently this means with mbox format that message flags have
been changed in index, but not written into mbox file yet. */
INDEX_MAIL_FLAG_DIRTY = 0x0004
#define IS_HEADER_FIELD(field) \
FIELD_TYPE_BCC | FIELD_TYPE_SUBJECT)) != 0)
#define IS_BODYSTRUCTURE_FIELD(field) \
FIELD_TYPE_MESSAGEPART)) != 0)
typedef enum {
MAIL_LOCK_UNLOCK = 0,
} MailLockType;
typedef struct _MailIndex MailIndex;
typedef struct _MailIndexData MailIndexData;
typedef struct _MailModifyLog MailModifyLog;
typedef struct _MailCustomFlags MailCustomFlags;
typedef struct _MailIndexHeader MailIndexHeader;
typedef struct _MailIndexDataHeader MailIndexDataHeader;
typedef struct _MailIndexRecord MailIndexRecord;
typedef struct _MailIndexDataRecord MailIndexDataRecord;
typedef struct _MailIndexUpdate MailIndexUpdate;
struct _MailIndexHeader {
unsigned char compat_data[8];
/* 0 = version
1 = flags,
2 = sizeof(unsigned int),
3 = sizeof(time_t),
4 = sizeof(uoff_t),
5 = MEM_ALIGN_SIZE */
unsigned int indexid;
unsigned int sync_id; /* re-mmap() when changed, required only
if file size is changed */
unsigned int flags;
unsigned int cache_fields;
unsigned int first_hole_index;
unsigned int first_hole_records;
unsigned int uid_validity;
unsigned int next_uid;
unsigned int messages_count;
unsigned int seen_messages_count;
unsigned int deleted_messages_count;
unsigned int last_nonrecent_uid;
/* these UIDs may not exist and may not even be unseen */
unsigned int first_unseen_uid_lowwater;
unsigned int first_deleted_uid_lowwater;
};
struct _MailIndexDataHeader {
unsigned int indexid;
unsigned int reserved; /* for alignment mostly */
};
struct _MailIndexRecord {
/* remember to keep uoff_t's 8 byte aligned so we don't waste space */
unsigned int uid;
unsigned int msg_flags; /* MailFlags */
unsigned int index_flags; /* MailIndexMailFlags */
unsigned int cached_fields; /* MailField */
unsigned int data_size;
};
struct _MailIndexDataRecord {
unsigned int field; /* MailField */
unsigned int full_field_size;
};
#define SIZEOF_MAIL_INDEX_DATA \
(sizeof(MailIndexDataRecord) - MEM_ALIGN_SIZE)
#define DATA_RECORD_SIZE(rec) \
struct _MailIndex {
/* If fast is TRUE, compressing and cache updates are not performed.
Note that opening same index twice in the same process is a bad
idea since they share the same file locks. As soon one of the
indexes is closed, the locks in second index are dropped which
especially hurts modify log since it keeps locks all the time. */
/* Free index from memory. */
reset error from get_last_error() as unlocking can be done as
a cleanup after some other function failed. Index is always
mmap()ed after set_lock() succeeds.
Trying to change a shared lock into exclusive lock is a fatal
error, since it may create a deadlock. Even though operating
system should detect it and fail, it's not a good idea to even
let it happen. Better ways to do this would be to a) mark the
data to be updated later, b) use try_lock() if the update is
preferred but not required, c) unlock + lock again, but make
sure that won't create race conditions */
/* Try locking the index. Returns TRUE if the lock was got and
FALSE if lock isn't possible to get currently or some other error
occured. Never blocks. */
/* Rebuild the whole index. Note that this changes the indexid
so all the other files must also be rebuilt after this call.
Index MUST NOT have shared lock, but exclusive lock or no lock at
all is fine. Note that this function may leave the index
exclusively locked, and always sets index->inconsistent = TRUE. */
/* Verify that the index is valid. If anything invalid is found,
index is set inconsistent and to be rebuilt at next open.
Same locking issues as with rebuild(). */
/* Synchronize the index with the mailbox. Same locking issues as
with rebuild(). */
/* Returns the index header (never fails). The index needs to be
locked before calling this function, and must be kept locked as
long as you keep using the returned structure. */
/* sequence -> data lookup. The index needs to be locked before calling
this function, and must be kept locked as long as you keep using
the returned structure. */
/* Return the next record after specified record, or NULL if it was
last record. The index must be locked all the time between
lookup() and last next() call. */
/* Find first existing UID in range. Sequence number is also retrieved
if seq_r is non-NULL. */
unsigned int first_uid,
unsigned int last_uid,
unsigned int *seq_r);
/* Find field from specified record, or NULL if it's not in index.
Makes sure that the field ends with \0. */
/* Find field from specified record, or NULL if it's not in index. */
/* Mark the fields to be cached later. If any of them is already
set in hdr->cache_fields, mark the caching to happen next time
index is opened. */
/* Open mail file and return it as mmap()ed IBuffer. If we fails,
we return NULL and set deleted = TRUE if failure was because the
mail was just deleted (ie. not an error). */
int *deleted);
/* Expunge a mail from index. Tree and modifylog is also updated. The
index must be exclusively locked before calling this function.
If seq is 0, the modify log isn't updated. This is useful if
after append() something goes wrong and you wish to delete the
mail immediately. If external_change is TRUE, the modify log is
always written.
Note that the sequence numbers also update immediately after this
call, so if you want to delete messages 1..4 just call this
function 4 times with seq being 1. */
unsigned int seq, int external_change);
/* Update mail flags. The index must be exclusively locked before
calling this function. This shouldn't be called in the middle of
update_begin() as it may modify location field. */
int external_change);
/* Append a new record to index. The index must be exclusively
locked before calling this function. The record pointer is
updated to the mmap()ed record. rec->uid is updated in
append_end(). */
/* Updating fields happens by calling update_begin(), one or more
update_field()s and finally update_end() which does the actual
updating. The index must be exclusively locked all this time.
update_begin() and update_field() functions cannot fail.
The extra_space parameter for update_field() specifies the amount
of extra empty space we should leave after the value, so that if
the field grows in future it could be expanded without copying it
to end of file. When the field already exists, the extra_space
is ignored.
The files may not actually be updated until after you've unlocked
the file. */
/* Just remember that full_field_size will be MEM_ALIGNed, so
it may differer from the given size parameter. */
/* Returns last error message */
/* Returns TRUE if last error was because we ran out of available
disk space. */
/* Returns TRUE if index is now in inconsistent state with the
previous known state, meaning that the message IDs etc. may
have changed - only way to recover this would be to fully close
the mailbox and reopen it. With IMAP connection this would mean
a forced disconnection since we can't do forced CLOSE. */
/* private: */
char *dir; /* directory where to place the index files */
char *filepath; /* index file path */
unsigned int indexid;
unsigned int sync_id;
char *mbox_path; /* mbox-specific path to the actual mbox file */
int mbox_fd;
int mbox_locks;
int mbox_lock_type;
int fd; /* opened index file */
char *error; /* last error message */
void *mmap_base;
unsigned int first_recent_uid;
unsigned int modifylog_id;
/* these fields are OR'ed to the fields in index header once we
get around grabbing exclusive lock */
unsigned int set_flags;
unsigned int set_cache_fields;
unsigned int anon_mmap:1;
unsigned int opened:1;
unsigned int inconsistent:1;
unsigned int nodiskspace:1;
};
/* needed to remove annoying warnings about not initializing all struct
members.. */
#define MAIL_INDEX_PRIVATE_FILL \
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, \
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, \
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, \
0
/* defaults - same as above but prefixed with mail_index_. */
unsigned int first_uid,
unsigned int last_uid,
unsigned int *seq_r);
unsigned int seq, int external_change);
int external_change);
/* INTERNAL: */
/* Max. mmap()ed size for a message */
/* Delete unused non-local temp files after 24h. Just to be sure we don't
delete it too early. The temp files don't harm much anyway. */
/* number of records to always keep allocated in index file,
either used or unused */
#define INDEX_MIN_RECORDS_COUNT 64
/* when empty space in index file gets full, grow the file n% larger */
#define INDEX_GROW_PERCENTAGE 10
/* ftruncate() the index file when only n% of it is in use */
#define INDEX_TRUNCATE_PERCENTAGE 30
/* don't truncate whole file anyway, keep n% of the empty space */
#define INDEX_TRUNCATE_KEEP_PERCENTAGE 10
/* Compress the file when deleted space reaches n% of total size */
#define INDEX_COMPRESS_PERCENTAGE 50
/* uoff_t to index file for given record */
/* index number for uoff_t position */
#define INDEX_POSITION_INDEX(pos) \
/* index number for given record */
/* mark the index corrupted */
#define INDEX_MARK_CORRUPTED(index) \
/* get number of records in mmaped index */
#define MAIL_INDEX_RECORD_COUNT(index) \
sizeof(MailIndexRecord))
/* minimum size for index file */
#define INDEX_FILE_MIN_SIZE \
(sizeof(MailIndexHeader) + \
INDEX_MIN_RECORDS_COUNT * sizeof(MailIndexRecord))
#endif