From 3a673adcc2ffde7ae38f14677efa288c4173d159 Mon Sep 17 00:00:00 2001
From: Art Cancro <ajc@citadel.org>
Date: Wed, 14 Feb 2024 12:03:02 -0500
Subject: [PATCH] Filters defined in RFC4791 9.7.1-9.7.5: DRY ingest

The code to parse these XML stanzas and ingest them into our filter
list was getting quite redundant.  This commit abstracts them into
a single handler.
---
 webcit-ng/server/caldav_reports.c | 88 ++++++++++++++-----------------
 1 file changed, 41 insertions(+), 47 deletions(-)

diff --git a/webcit-ng/server/caldav_reports.c b/webcit-ng/server/caldav_reports.c
index b28554e0c..f4eb6c06a 100644
--- a/webcit-ng/server/caldav_reports.c
+++ b/webcit-ng/server/caldav_reports.c
@@ -69,53 +69,25 @@ void caldav_xml_start(void *data, const char *el, const char **attr) {
 		crp->filters = array_new(SIZ);
 	}
 
-	// RFC4791 9.7.1 CALDAV:comp-filter XML Element
-	else if (	(!strcasecmp(el, "urn:ietf:params:xml:ns:caldav:comp-filter"))
-			&& (crp->filters)
-			&& (attr[0])
-			&& (attr[1])
+	// Handle the filters defined in RFC4791 9.7.1 through 9.7.5
+	else if (	(	(!strcasecmp(el, "urn:ietf:params:xml:ns:caldav:comp-filter"))
+				|| (!strcasecmp(el, "urn:ietf:params:xml:ns:caldav:prop-filter"))
+				|| (!strcasecmp(el, "urn:ietf:params:xml:ns:caldav:param-filter"))
+				|| (!strcasecmp(el, "urn:ietf:params:xml:ns:caldav:is-not-defined"))
+				|| (!strcasecmp(el, "urn:ietf:params:xml:ns:caldav:text-match"))
+			)
+			&& (crp->filters)			// Make sure we actually allocated an array
 	) {
 		char newfilter[SIZ];
-		snprintf(newfilter, SIZ, "comp-filter|%s|%s", attr[0], attr[1]);
+		int a = 0;
+		int len = snprintf(newfilter, SIZ, &el[23]);	// strip off "urn:ietf:params:xml:ns:caldav:" for our purposes
+		while (attr[a]) {
+			len += snprintf(&newfilter[len], SIZ-len, "|%s", attr[a++]);	// now save the attributes
+		}
 		array_append(crp->filters, newfilter);
 		syslog(LOG_DEBUG, "%s", newfilter);
 	}
 
-	// RFC4791 9.7.2 CALDAV:prop-filter XML Element
-	else if (!strcasecmp(el, "urn:ietf:params:xml:ns:caldav:prop-filter")) {
-		if (crp->filters) {
-			char newfilter[SIZ];
-			snprintf(newfilter, SIZ, "hi there");
-			array_append(crp->filters, newfilter);
-		}
-	}
-
-	// RFC4791 9.7.3 CALDAV:param-filter XML Element
-	else if (!strcasecmp(el, "urn:ietf:params:xml:ns:caldav:param-filter")) {
-		if (crp->filters) {
-			char newfilter[SIZ];
-			snprintf(newfilter, SIZ, "hi there");
-			array_append(crp->filters, newfilter);
-		}
-	}
-
-	// RFC4791 9.7.4 CALDAV:is-not-defined XML Element
-	else if (!strcasecmp(el, "urn:ietf:params:xml:ns:caldav:is-not-defined")) {
-		if (crp->filters) {
-			char newfilter[SIZ];
-			snprintf(newfilter, SIZ, "hi there");
-			array_append(crp->filters, newfilter);
-		}
-	}
-
-	// RFC4791 9.7.5 CALDAV:text-match XML Element
-	else if (!strcasecmp(el, "urn:ietf:params:xml:ns:caldav:text-match")) {
-		if (crp->filters) {
-			char newfilter[SIZ];
-			snprintf(newfilter, SIZ, "hi there");
-			array_append(crp->filters, newfilter);
-		}
-	}
 }
 
 
@@ -293,8 +265,31 @@ void caldav_report_one_item(struct http_transaction *h, struct ctdlsession *c, S
 }
 
 
-void caldav_apply_filter(struct cr_params *crp, char *xml_body, long xml_length) {
-	TRACE;
+// Called by caldav_apply_filters() to apply ONE filter.
+// Returns 0 if the calendar item does not match the filter.
+// Returns 1 if the calendar item DOES match the filter.
+int caldav_apply_one_filter(void *cal, char *filter) {
+	syslog(LOG_DEBUG, "applying filter: %s", filter);
+	return(1);
+}
+
+
+// Recursive function to apply CalDAV FILTERS to a calendar item.
+// Returns zero if the calendar item was disqualified by a filter, nonzero if the calendar item still qualifies.
+int caldav_apply_filters(void *cal, Array *filters, int index) {
+
+	// Apply *this* filter.
+	if (caldav_apply_one_filter(cal, array_get_element_at(filters, index)) == 0) {
+		return(0);
+	}
+
+	// If we get to this point, the current filter has passed, and we move on to the next one.
+	if (index < array_len(filters)-1) {
+		return(caldav_apply_filters(cal, filters, index+1));
+	}
+
+	// If we got this far, every filter passed, and the calendar item qualifies for output.
+	return(1);
 }
 
 
@@ -358,10 +353,9 @@ void caldav_report(struct http_transaction *h, struct ctdlsession *c) {
 				// Does this calendar item qualify for output?
 				int qualify = 1;
 
-				// FIXME put filters here
-				if (crp.filters) {
-					// apply the filters
-				}
+				// If there was a filter stanza, run this calendar item through the filters.
+				qualify = caldav_apply_filters(cal, crp.filters, 0);
+				syslog(LOG_DEBUG, "Message %ld does%s qualify", m, (qualify ? "" : " NOT"));
 
 				// Did this calendar item match the query?  If so, output it.
 				if (qualify) {
-- 
2.30.2