diff options
Diffstat (limited to 'uid.c')
| -rw-r--r-- | uid.c | 103 |
1 files changed, 95 insertions, 8 deletions
@@ -63,9 +63,45 @@ * be picked up by the next run. If there are no un-expunged * messages, the file is deleted. * + * One disadvantage of UIDL is that all the UIDs have to be downloaded + * before a search for new messages can be done. Typically, new messages + * are appended to mailboxes. Hence, downloading all UIDs just to download + * a few new mails is a waste of bandwidth. If new messages are always at + * the end of the mailbox, fast UIDL will decrease the time required to + * download new mails. + * + * During fast UIDL, the UIDs of all messages are not downloaded! The first + * unseen message is searched for by using a binary search on UIDs. UIDs + * after the first unseen message are downloaded as and when needed. + * + * The advantages of fast UIDL are (this is noticeable only when the + * mailbox has too many mails): + * + * - There is no need to download the UIDs of all mails right at the start. + * - There is no need to save all the UIDs in memory separately in + * `newsaved' list. + * - There is no need to download the UIDs of seen mail (except for the + * first binary search). + * - The first new mail is downloaded considerably faster. + * + * The disadvantages are: + * + * - Since all UIDs are not downloaded, it is not possible to swap old and + * new list. The current state of the mailbox is essentially a merged state + * of old and new mails. + * - If an intermediate mail has been temporarily refused (say, due to 4xx + * code from the smtp server), this mail may not get downloaded. + * - If 'flush' is used, such intermediate mails will also get deleted. + * + * The first two disadvantages can be overcome by doing a linear search + * once in a while (say, every 10th poll). Also, with flush, fast UIDL + * should be disabled. + * * Note: some comparisons (those used for DNS address lists) are caseblind! */ +int dofastuidl = 0; + /* UIDs associated with un-queried hosts */ static struct idlist *scratchlist; @@ -305,20 +341,20 @@ void free_str_pair_list(struct idlist **idl) } #endif -int str_in_list(struct idlist **idl, const char *str, const flag caseblind) +struct idlist *str_in_list(struct idlist **idl, const char *str, const flag caseblind) /* is a given ID in the given list? (comparison may be caseblind) */ { struct idlist *walk; if (caseblind) { for( walk = *idl; walk; walk = walk->next ) if( strcasecmp( str, (char *)walk->id) == 0 ) - return 1; + return walk; } else { for( walk = *idl; walk; walk = walk->next ) if( strcmp( str, (char *)walk->id) == 0 ) - return 1; + return walk; } - return 0; + return NULL; } int str_nr_in_list( struct idlist **idl, const char *str ) @@ -389,6 +425,16 @@ char *str_find(struct idlist **idl, long number) return(str_find(&(*idl)->next, number)); } +struct idlist *id_find(struct idlist **idl, long number) +/* return the id of the given number in the given list. */ +{ + struct idlist *idp; + for (idp = *idl; idp; idp = idp->next) + if (idp->val.status.num == number) + return(idp); + return(0); +} + char *idpair_find(struct idlist **idl, const char *id) /* return the id of the given id in the given list (caseblind comparison) */ { @@ -449,7 +495,7 @@ void expunge_uids(struct query *ctl) { struct idlist *idl; - for (idl = ctl->newsaved; idl; idl = idl->next) + for (idl = dofastuidl ? ctl->oldsaved : ctl->newsaved; idl; idl = idl->next) if (idl->val.status.mark == UID_DELETED) idl->val.status.mark = UID_EXPUNGED; } @@ -462,8 +508,11 @@ void uid_swap_lists(struct query *ctl) { struct idlist *idp; - report_build(stdout, GT_("New UID list from %s:"), ctl->server.pollname); - for (idp = ctl->newsaved; idp; idp = idp->next) + if (dofastuidl) + report_build(stdout, GT_("Merged UID list from %s:"), ctl->server.pollname); + else + report_build(stdout, GT_("New UID list from %s:"), ctl->server.pollname); + for (idp = dofastuidl ? ctl->oldsaved : ctl->newsaved; idp; idp = idp->next) report_build(stdout, " %s = %d", idp->id, idp->val.status.mark); if (!idp) report_build(stdout, GT_(" <empty>")); @@ -495,10 +544,48 @@ void uid_swap_lists(struct query *ctl) ctl->oldsaved = ctl->newsaved; ctl->newsaved = (struct idlist *) NULL; } - else if (outlevel >= O_DEBUG) + /* in fast uidl, there is no need to swap lists: the old state of + * mailbox cannot be discarded! */ + else if (outlevel >= O_DEBUG && !dofastuidl) report(stdout, GT_("not swapping UID lists, no UIDs seen this query\n")); } +void uid_discard_new_list(struct query *ctl) +/* finish a query which had errors */ +{ + /* debugging code */ + if (ctl->server.uidl && outlevel >= O_DEBUG) + { + struct idlist *idp; + + /* this is now a merged list! the mails which were seen in this + * poll are marked here. */ + report_build(stdout, GT_("Merged UID list from %s:"), ctl->server.pollname); + for (idp = ctl->oldsaved; idp; idp = idp->next) + report_build(stdout, " %s = %d", idp->id, idp->val.status.mark); + if (!idp) + report_build(stdout, GT_(" <empty>")); + report_complete(stdout, "\n"); + } + + if (ctl->newsaved) + { + /* new state of mailbox is not reliable */ + if (outlevel >= O_DEBUG) + report(stdout, GT_("discarding new UID list\n")); + free_str_list(&ctl->newsaved); + ctl->newsaved = (struct idlist *) NULL; + } +} + +void uid_reset_num(struct query *ctl) +/* reset the number associated with each id */ +{ + struct idlist *idp; + for (idp = ctl->oldsaved; idp; idp = idp->next) + idp->val.status.num = 0; +} + void write_saved_lists(struct query *hostlist, const char *idfile) /* perform end-of-run write of seen-messages list */ { |