Initial revision

svn path=/trunk/; revision=167

1 files changed, 207 insertions, 0 deletions

diff --git a/uid.c b/uid.c
new file mode 100644
index 00000000..06acd5a9
--- /dev/null
+++ b/uid.c
@@ -0,0 +1,207 @@
+/* Copyright 1993-95 by Carl Harris, Jr. Copyright 1996 by Eric S. Raymond
+ * All rights reserved.
+ * For license terms, see the file COPYING in this directory.
+ */
+
+/***********************************************************************
+  module:       uid.c
+  project:      fetchmail
+  programmer:   Eric S. Raymond
+  description:	UID list handling
+
+ ***********************************************************************/
+
+#include <config.h>
+
+#include <stdio.h>
+
+#if defined(STDC_HEADERS)
+#include <stdlib.h>
+#include <string.h>
+#endif
+
+#if defined(HAVE_UNISTD_H)
+#include <unistd.h>
+#endif
+
+#include "fetchmail.h"
+
+/*
+ * Machinery for handling UID lists live here.  This is mainly to support
+ * RFC1725-conformant POP3 servers without a LAST command, but may also be
+ * useful for making the IMAP4 querying logic UID-oriented, if I feel
+ * sufficiently motivated at some point.
+ *
+ * Here's the theory:
+ *
+ * At start of a query, we have a (possibly empty) list of UIDs to be
+ * considered `already seen'.  These are messages that were left in
+ * the mailbox and *not deleted* on previous queries (we don't need to
+ * remember the UIDs of deleted messages because ... well, they're gone!).
+ * This list is set up by initialized_saved_list() from the .fetchids 
+ * file and hangs off the host's `saved' member.
+ *
+ * Early in the query, during the execution of the protocol-specific 
+ * getrange code, the driver expects that the host's `listed' member
+ * will be filled with a list of UIDs and message numbers representing
+ * the current mailbox state.  If this list is empty, the server did
+ * not respond to the request for a UID listing.
+ *
+ * Each time a message is fetched, we can check its UID against the
+ * `saved' list to see if it is old.  If not, it should be downloaded
+ * (and possibly deleted).  It should be downloaded anyway if --all
+ * is on.  It should not be deleted if --keep is on.
+ *
+ * Each time a message is deleted, we remove its id from the `listed'
+ * member.
+ *
+ * At the end of the query, whatever remains in the `listed' member
+ * (because it was not deleted) becomes the `saved' list.  The old
+ * `saved' list is freed.
+ */
+
+/* UIDs associated with un-queried hosts */
+static struct idlist *scratchlist;
+
+void initialize_saved_lists(hostlist, idfile)
+/* read file of saved IDs and attach to each host */
+struct hostrec *hostlist;
+char *idfile;
+{
+    int	st;
+    FILE	*tmpfp;
+    struct hostrec *hostp;
+
+    /* make sure lists are initially empty */
+    for (hostp = hostlist; hostp; hostp = hostp->next)
+	hostp->saved = hostp->mailbox = (struct idlist *)NULL;
+
+    /* let's get stored message UIDs from previous queries */
+    if ((tmpfp = fopen(idfile, "r")) != (FILE *)NULL) {
+	char buf[POPBUFSIZE+1], host[HOSTLEN+1], id[IDLEN+1];
+
+	while (fgets(buf, POPBUFSIZE, tmpfp) != (char *)NULL)
+	{
+	    if ((st = sscanf(buf, "%s %s\n", host, id)) == 2)
+	    {
+		for (hostp = hostlist; hostp; hostp = hostp->next)
+		{
+		    if (strcmp(host, hostp->servername) == 0)
+		    {
+			save_uid(&hostp->saved, -1, id);
+			break;
+		    }
+		}
+
+		/* if it's not in a host we're querying, save it anyway */
+		if (hostp == (struct hostrec *)NULL)
+		    save_uid(&scratchlist, -1, buf);
+	    }
+	}
+	fclose(tmpfp);
+    }
+}
+
+void save_uid(idl, num, str)
+/* save a number/UID pair on the given UID list */
+struct idlist **idl;
+int num;
+char *str;
+{
+    struct idlist *new;
+
+    new = (struct idlist *)xmalloc(sizeof(struct idlist));
+    new->num = num;
+    new->id = strdup(str);
+    new->next = *idl;
+    *idl = new;
+}
+
+void free_uid_list(idl)
+/* free the given UID list */
+struct idlist **idl;
+{
+    if (*idl == (struct idlist *)NULL)
+	return;
+
+    free_uid_list(&(*idl)->next);
+    free ((*idl)->id);
+    free(*idl);
+    *idl = (struct idlist *)NULL;
+}
+
+int uid_in_list(idl, str)
+/* is a given ID in the given list? */
+struct idlist **idl;
+char *str;
+{
+    if (*idl == (struct idlist *)NULL)
+	return(0);
+    else if (strcmp(str, (*idl)->id) == 0)
+	return(1);
+    else
+	return(uid_in_list(&(*idl)->next, str));
+}
+
+int delete_uid(idl, str)
+/* delete given UID from given list */
+struct idlist **idl;
+char *str;
+{
+    if (*idl == (struct idlist *)NULL)
+	return(0);
+    else if (strcmp((*idl)->id, str) == 0)
+    {
+	struct idlist	*next = (*idl)->next;
+
+	free ((*idl)->id);
+	free(*idl);
+	*idl = next;
+	return(1);
+    }
+    else
+	return(delete_uid(&(*idl)->next, str));
+    return(0);
+}
+
+void update_uid_lists(hostp)
+/* perform end-of-query actions on UID lists */
+struct hostrec *hostp;
+{
+    /*
+     * Replace `saved' list with `mailbox' list as modified by deletions.
+     */
+    free_uid_list(&hostp->saved);
+    hostp->saved = hostp->mailbox;
+}
+
+void write_saved_lists(hostlist, idfile)
+struct hostrec *hostlist;
+char *idfile;
+{
+    int	st, idcount;
+    FILE	*tmpfp;
+    struct hostrec *hostp;
+    struct idlist *idp;
+
+    /* if all lists are empty, nuke the file */
+    idcount = 0;
+    for (hostp = hostlist; hostp; hostp = hostp->next) {
+	if (hostp->saved)
+	    idcount++;
+    }
+
+    /* either nuke the file or write updated last-seen IDs */
+    if (!idcount)
+	unlink(idfile);
+    else
+	if ((tmpfp = fopen(idfile, "w")) != (FILE *)NULL) {
+	    for (hostp = hostlist; hostp; hostp = hostp->next) {
+		for (idp = hostp->saved; idp; idp = idp->next)
+		    fprintf(tmpfp, "%s %s\n", hostp->servername, idp->id);
+	    }
+	    for (idp = scratchlist; idp; idp = idp->next)
+		fputs(idp->id, tmpfp);
+	    fclose(tmpfp);
+	}
+}