icalcomponent_get_duration() — calculate the duration differently for VEVENT and VTODO

icalcomponent_get_dtend() — return null-time, unless called on VEVENT, VAVAILABILITY or VFREEBUSY.

4 files changed, 129 insertions, 23 deletions

diff --git a/ReleaseNotes.txt b/ReleaseNotes.txt
index cd82f85c..c7bd29de 100644
--- a/ReleaseNotes.txt
+++ b/ReleaseNotes.txt
@@ -3,7 +3,8 @@ Release Highlights
 
 Version 3.0.13 (UNRELEASED):
 ----------------------------
- *
+ * icalcomponent_get_dtend() return icaltime_null_time(), unless called on VEVENT, VAVAILABILITY or VFREEBUSY
+ * icalcomponent_get_duration() for VTODO calculate with DUE instead of DTEND
 
 Version 3.0.12 (08 December 2021):
 ----------------------------------
diff --git a/src/libical/icalcomponent.c b/src/libical/icalcomponent.c
index 1a3655b9..dc085709 100644
--- a/src/libical/icalcomponent.c
+++ b/src/libical/icalcomponent.c
@@ -1337,10 +1337,23 @@ struct icaltimetype icalcomponent_get_dtstart(icalcomponent *comp)
 struct icaltimetype icalcomponent_get_dtend(icalcomponent *comp)
 {
     icalcomponent *inner = icalcomponent_get_inner(comp);
-    icalproperty *end_prop = icalcomponent_get_first_property(inner, ICAL_DTEND_PROPERTY);
-    icalproperty *dur_prop = icalcomponent_get_first_property(inner, ICAL_DURATION_PROPERTY);
+    const icalcomponent_kind kind = icalcomponent_isa(inner);
+    icalproperty *end_prop, *dur_prop;
     struct icaltimetype ret;
 
+    switch(kind) {
+    case ICAL_VAVAILABILITY_COMPONENT:
+    case ICAL_VEVENT_COMPONENT:
+    case ICAL_VFREEBUSY_COMPONENT:
+    case ICAL_XAVAILABLE_COMPONENT:
+        break;
+    default:
+        return icaltime_null_time();
+    }
+
+    end_prop = icalcomponent_get_first_property(inner, ICAL_DTEND_PROPERTY);
+    dur_prop = icalcomponent_get_first_property(inner, ICAL_DURATION_PROPERTY);
+
     if (end_prop != 0 && dur_prop == 0) {
         ret = icalproperty_get_datetime_with_component(end_prop, comp);
     } else if (end_prop == 0 && dur_prop != 0) {
@@ -1357,13 +1370,17 @@ struct icaltimetype icalcomponent_get_dtend(icalcomponent *comp)
 
         ret = icaltime_add(start, duration);
     } else if (end_prop == 0 && dur_prop == 0) {
-        struct icaltimetype start = icalcomponent_get_dtstart(inner);
-        if (icaltime_is_date(start)) {
-            struct icaldurationtype duration = icaldurationtype_null_duration();
-            duration.days = 1;
-            ret = icaltime_add(start, duration);
+        if (kind == ICAL_VEVENT_COMPONENT) {
+            struct icaltimetype start = icalcomponent_get_dtstart(inner);
+            if (icaltime_is_date(start)) {
+                struct icaldurationtype duration = icaldurationtype_null_duration();
+                duration.days = 1;
+                ret = icaltime_add(start, duration);
+            } else {
+                ret = start;
+            }
         } else {
-            ret = start;
+            ret = icaltime_null_time();
         }
     } else {
         /* Error, both duration and dtend have been specified */
@@ -1419,12 +1436,32 @@ void icalcomponent_set_duration(icalcomponent *comp, struct icaldurationtype v)
 struct icaldurationtype icalcomponent_get_duration(icalcomponent *comp)
 {
     icalcomponent *inner = icalcomponent_get_inner(comp);
+    const icalcomponent_kind kind = icalcomponent_isa(inner);
+    icalproperty *end_prop, *dur_prop;
+    struct icaltimetype end;
+    struct icaldurationtype ret;
+
+    switch(kind) {
+    case ICAL_VAVAILABILITY_COMPONENT:
+    case ICAL_VEVENT_COMPONENT:
+    case ICAL_XAVAILABLE_COMPONENT:
+        end_prop = icalcomponent_get_first_property(inner, ICAL_DTEND_PROPERTY);
+        if (end_prop) {
+            end = icalcomponent_get_dtend(inner);
+        }
+        break;
+    case ICAL_VTODO_COMPONENT:
+        end_prop = icalcomponent_get_first_property(inner, ICAL_DUE_PROPERTY);
+        if (end_prop) {
+            end = icalcomponent_get_due(inner);
+        }
+        break;
+    default:
+        /* The libical API is used incorrectly */
+        return icaldurationtype_null_duration();
+    }
 
-    icalproperty *end_prop = icalcomponent_get_first_property(inner, ICAL_DTEND_PROPERTY);
-
-    icalproperty *dur_prop = icalcomponent_get_first_property(inner, ICAL_DURATION_PROPERTY);
-
-    struct icaldurationtype ret = icaldurationtype_null_duration();
+    dur_prop = icalcomponent_get_first_property(inner, ICAL_DURATION_PROPERTY);
 
     if (dur_prop != 0 && end_prop == 0) {
         ret = icalproperty_get_duration(dur_prop);
@@ -1436,15 +1473,16 @@ struct icaldurationtype icalcomponent_get_duration(icalcomponent *comp)
          * The standard actually allows different time zones.
          */
         struct icaltimetype start = icalcomponent_get_dtstart(inner);
-        struct icaltimetype end = icalcomponent_get_dtend(inner);
 
         ret = icaltime_subtract(end, start);
     } else if (end_prop == 0 && dur_prop == 0) {
         struct icaltimetype start = icalcomponent_get_dtstart(inner);
-        if (icaltime_is_date(start)) {
+        ret = icaldurationtype_null_duration();
+        if (kind == ICAL_VEVENT_COMPONENT && icaltime_is_date(start)) {
             ret.days = 1;
         }
     } else {
+        ret = icaldurationtype_null_duration();
         /* Error, both duration and dtend have been specified */
         icalerror_set_errno(ICAL_MALFORMEDDATA_ERROR);
     }
diff --git a/src/libical/icalcomponent.h b/src/libical/icalcomponent.h
index 5e44fe26..70533a34 100644
--- a/src/libical/icalcomponent.h
+++ b/src/libical/icalcomponent.h
@@ -263,6 +263,13 @@ LIBICAL_ICAL_EXPORT struct icaltimetype icalcomponent_get_dtstart(icalcomponent
  *      there is a DTEND and you call get_duration, the routine will
  *      return the difference between DTEND and DTSTART.
  *
+ *      When DURATION and DTEND are both missing, for VEVENT an implicit
+ *      DTEND is calculated based of DTSTART; for AVAILABLE, VAVAILABILITY,
+ *      and VFREEBUSY null-time is returned.
+ *
+ *      Returns null-time, unless called on AVAILABLE, VEVENT,
+ *      VAVAILABILITY, or VFREEBUSY components.
+ *
  *      FIXME this is useless until we can flag the failure
  */
 LIBICAL_ICAL_EXPORT struct icaltimetype icalcomponent_get_dtend(icalcomponent *comp);
@@ -327,15 +334,14 @@ LIBICAL_ICAL_EXPORT void icalcomponent_set_duration(icalcomponent *comp,
 /**     @brief Gets the DURATION property as an icalduration
  *
  *      For the icalcomponent routines only, DTEND and DURATION are tied
- *      together.
- *      If a DURATION property is not present but a DTEND is, we use
- *      that to determine the proper end.
- *
- *      For the icalcomponent routines only, dtend and duration are tied
  *      together. If you call the get routine for one and the other
  *      exists, the routine will calculate the return value. That is, if
- *      there is a DTEND and you call get_duration, the routine will
- *      return the difference between DTEND and DTSTART.
+ *      there is a DTEND and you call get_duration, the routine will return
+ *      the difference between DTEND and DTSTART in AVAILABLE, VEVENT, or
+ *      VAVAILABILITY; and the difference between DUE and DTSTART in VTODO.
+ *      When both DURATION and DTEND are missing from VEVENT an implicit
+ *      duration is returned, based on the value-type of DTSTART. Otherwise
+ *      null-duration is returned.
  */
 LIBICAL_ICAL_EXPORT struct icaldurationtype icalcomponent_get_duration(icalcomponent *comp);
 
diff --git a/src/test/regression.c b/src/test/regression.c
index 41171169..076922b5 100644
--- a/src/test/regression.c
+++ b/src/test/regression.c
@@ -4772,6 +4772,66 @@ static void test_vcc_vcard_parse(void)
     ok("vCalendar-broken cannot be parsed", (vcal == NULL));
 }
 
+static void test_implicit_dtend_duration(void)
+{
+    const struct icaltimetype start1 = icaltime_from_string("20220108");
+    icalcomponent* c = icalcomponent_vanew(
+            ICAL_VCALENDAR_COMPONENT,
+            icalcomponent_vanew(
+                ICAL_VEVENT_COMPONENT,
+                icalproperty_vanew_dtstart(start1, 0),
+                0),
+            0);
+    struct icaldurationtype d = icalcomponent_get_duration(c);
+    struct icaltimetype end = icalcomponent_get_dtend(c),
+        start = icaltime_from_string("20220108T101010Z");
+    if (VERBOSE) {
+        printf("%s\n", icaldurationtype_as_ical_string(d));
+    }
+    str_is("icaldurationtype_as_ical_string(d)", "P1D", icaldurationtype_as_ical_string(d));
+
+    if (VERBOSE) {
+        printf("%s\n", icaltime_as_ical_string(end));
+    }
+    str_is("icaltime_as_ical_string(end)", "20220109", icaltime_as_ical_string(end));
+
+    icalcomponent_set_dtstart(c, start);
+    d = icalcomponent_get_duration(c);
+    end = icalcomponent_get_dtend(c);
+    if (VERBOSE) {
+        printf("%s\n", icaldurationtype_as_ical_string(d));
+    }
+    int_is("icaldurationtype_as_int(d)", 0, icaldurationtype_as_int(d));
+
+    if (VERBOSE) {
+        printf("%s\n", icaltime_as_ical_string(end));
+    }
+    int_is("icaltime_compare(start, end)", 0, icaltime_compare(start, end));
+    icalcomponent_free(c);
+
+
+    c = icalcomponent_vanew(
+            ICAL_VCALENDAR_COMPONENT,
+                icalcomponent_vanew(
+                    ICAL_VTODO_COMPONENT,
+                    icalproperty_vanew_dtstart(start1, 0),
+                    0),
+            0);
+    icalcomponent_set_due(c, icaltime_from_string("20220109"));
+    d = icalcomponent_get_duration(c);
+    end = icalcomponent_get_dtend(c);
+    if (VERBOSE) {
+        printf("%s\n", icaldurationtype_as_ical_string(d));
+    }
+    str_is("P1D", "P1D", icaldurationtype_as_ical_string(d));
+
+    if (VERBOSE) {
+        printf("%i\n", icaltime_is_null_time(end));
+    }
+    int_is("icaltime_is_null_time(end)", 1, icaltime_is_null_time(end));
+    icalcomponent_free(c);
+}
+
 int main(int argc, char *argv[])
 {
 #if !defined(HAVE_UNISTD_H)
@@ -4911,6 +4971,7 @@ int main(int argc, char *argv[])
     test_run("Test icalcomponent_normalize", test_icalcomponent_normalize, do_test, do_header);
     test_run("Test builtin compat TZID", test_builtin_compat_tzid, do_test, do_header);
     test_run("Test VCC vCard parse", test_vcc_vcard_parse, do_test, do_header);
+    test_run("Test implicit DTEND and DURATION for VEVENT and VTODO", test_implicit_dtend_duration, do_test, do_header);
 
     /** OPTIONAL TESTS go here... **/