webcit/ical_dezonify.c

   1 /*
   2  * $Id$
   3  */
   4 /**
   5  * \defgroup IcalDezonify normalize ical dates to UTC
   6  * Function to go through an ical component set and convert all non-UTC
   7  * date/time properties to UTC.  It also strips out any VTIMEZONE
   8  * subcomponents afterwards, because they're irrelevant.
   9  *
  10  * Everything here will work on both a fully encapsulated VCALENDAR component
  11  * or any type of subcomponent.
  12  *
  13  * \ingroup Calendaring
  14  */
  15 /*@{*/
  16
  17 #include "webcit.h"
  18 #include "webserver.h"
  19
  20
  21 #ifdef WEBCIT_WITH_CALENDAR_SERVICE
  22
  23
  24 /*
  25  * Figure out which time zone needs to be used for timestamps that are
  26  * not UTC and do not have a time zone specified.
  27  *
  28  */
  29 icaltimezone *get_default_icaltimezone(void) {
  30
  31         icaltimezone *zone = NULL;
  32
  33         if (!zone) {
  34                 zone = icaltimezone_get_builtin_timezone(serv_info.serv_default_cal_zone);
  35         }
  36         if (!zone) {
  37                 zone = icaltimezone_get_utc_timezone();
  38         }
  39         return zone;
  40 }
  41
  42
  43 /*
  44  * Back end function for ical_dezonify()
  45  *
  46  * We supply this with the master component, the relevant component,
  47  * and the property (which will be a DTSTART, DTEND, etc.)
  48  * which we want to convert to UTC.
  49  */
  50 void ical_dezonify_backend(icalcomponent *cal,
  51                         icalcomponent *rcal,
  52                         icalproperty *prop) {
  53
  54         icaltimezone *t = NULL;
  55         icalparameter *param;
  56         const char *tzid = NULL;
  57         struct icaltimetype TheTime;
  58         int utc_declared_as_tzid = 0;   /**< Component declared 'TZID=GMT' instead of using Z syntax */
  59
  60         /* Give me nothing and I will give you nothing in return. */
  61         if (cal == NULL) return;
  62
  63         /* Hunt for a TZID parameter in this property. */
  64         param = icalproperty_get_first_parameter(prop, ICAL_TZID_PARAMETER);
  65
  66         /* Get the stringish name of this TZID. */
  67         if (param != NULL) {
  68                 tzid = icalparameter_get_tzid(param);
  69
  70                 /* Convert it to an icaltimezone type. */
  71                 if (tzid != NULL) {
  72                         /* lprintf(9, "                * Stringy supplied timezone is: '%s'\n", tzid); */
  73                         if ( (!strcasecmp(tzid, "UTC")) || (!strcasecmp(tzid, "GMT")) ) {
  74                                 utc_declared_as_tzid = 1;
  75                                 /* lprintf(9, "                * ...and we handle that internally.\n"); */
  76                         }
  77                         else {
  78                                 t = icalcomponent_get_timezone(cal, tzid);
  79                                 /* lprintf(9, "                * ...and I %s have tzdata for that zone.\n",
  80                                         (t ? "DO" : "DO NOT")
  81                                 ); */
  82                         }
  83                 }
  84
  85         }
  86
  87         /* Now we know the timezone.  Convert to UTC. */
  88
  89         if (icalproperty_isa(prop) == ICAL_DTSTART_PROPERTY) {
  90                 TheTime = icalproperty_get_dtstart(prop);
  91         }
  92         else if (icalproperty_isa(prop) == ICAL_DTEND_PROPERTY) {
  93                 TheTime = icalproperty_get_dtend(prop);
  94         }
  95         else if (icalproperty_isa(prop) == ICAL_DUE_PROPERTY) {
  96                 TheTime = icalproperty_get_due(prop);
  97         }
  98         else if (icalproperty_isa(prop) == ICAL_EXDATE_PROPERTY) {
  99                 TheTime = icalproperty_get_exdate(prop);
 100         }
 101         else {
 102                 return;
 103         }
 104
 105         /* lprintf(9, "                * Was: %s\n", icaltime_as_ical_string(TheTime)); */
 106
 107         if (TheTime.is_utc) {
 108                 /* lprintf(9, "                * This property is ALREADY UTC.\n"); */
 109         }
 110
 111         else if (utc_declared_as_tzid) {
 112                 /* lprintf(9, "                * Replacing '%s' TZID with 'Z' suffix.\n", tzid); */
 113                 TheTime.is_utc = 1;
 114         }
 115
 116         else {
 117                 /* Do the conversion. */
 118                 if (t != NULL) {
 119                         /* lprintf(9, "                * Timezone prop found.  Converting to UTC.\n"); */
 120                 }
 121                 else {
 122                         /* lprintf(9, "                * Converting default timezone to UTC.\n"); */
 123                 }
 124
 125                 if (t == NULL) {
 126                         icaltimezone_convert_time(&TheTime,
 127                                                 get_default_icaltimezone(),
 128                                                 icaltimezone_get_utc_timezone()
 129                         );
 130                 }
 131                 else {
 132                         icaltimezone_convert_time(&TheTime,
 133                                                 t,
 134                                                 icaltimezone_get_utc_timezone()
 135                         );
 136                         icaltimezone_free (t, 1);
 137                 }
 138                 TheTime.is_utc = 1;
 139         }
 140
 141         icalproperty_remove_parameter_by_kind(prop, ICAL_TZID_PARAMETER);
 142         /* lprintf(9, "                * Now: %s\n", icaltime_as_ical_string(TheTime)); */
 143
 144         /* Now add the converted property back in. */
 145         if (icalproperty_isa(prop) == ICAL_DTSTART_PROPERTY) {
 146                 icalproperty_set_dtstart(prop, TheTime);
 147         }
 148         else if (icalproperty_isa(prop) == ICAL_DTEND_PROPERTY) {
 149                 icalproperty_set_dtend(prop, TheTime);
 150         }
 151         else if (icalproperty_isa(prop) == ICAL_DUE_PROPERTY) {
 152                 icalproperty_set_due(prop, TheTime);
 153         }
 154         else if (icalproperty_isa(prop) == ICAL_EXDATE_PROPERTY) {
 155                 icalproperty_set_exdate(prop, TheTime);
 156         }
 157 }
 158
 159
 160 /*
 161  * Recursive portion of ical_dezonify()
 162  */
 163 void ical_dezonify_recurse(icalcomponent *cal, icalcomponent *rcal) {
 164         icalcomponent *c;
 165         icalproperty *p;
 166
 167         /*
 168          * Recurse through all subcomponents *except* VTIMEZONE ones.
 169          */
 170         for (c=icalcomponent_get_first_component(
 171                                         rcal, ICAL_ANY_COMPONENT);
 172                 c != NULL;
 173                 c = icalcomponent_get_next_component(
 174                                         rcal, ICAL_ANY_COMPONENT)
 175         ) {
 176                 if (icalcomponent_isa(c) != ICAL_VTIMEZONE_COMPONENT) {
 177                         ical_dezonify_recurse(cal, c);
 178                 }
 179         }
 180
 181         /*
 182          * Now look for DTSTART and DTEND properties
 183          */
 184         for (p=icalcomponent_get_first_property(rcal, ICAL_ANY_PROPERTY);
 185                 p != NULL;
 186                 p = icalcomponent_get_next_property(rcal, ICAL_ANY_PROPERTY)
 187         ) {
 188                 if (
 189                         (icalproperty_isa(p) == ICAL_DTSTART_PROPERTY)
 190                         || (icalproperty_isa(p) == ICAL_DTEND_PROPERTY)
 191                         || (icalproperty_isa(p) == ICAL_DUE_PROPERTY)
 192                         || (icalproperty_isa(p) == ICAL_EXDATE_PROPERTY)
 193                    ) {
 194                         ical_dezonify_backend(cal, rcal, p);
 195                 }
 196         }
 197 }
 198
 199
 200 /*
 201  * Convert all DTSTART and DTEND properties in all subcomponents to UTC.
 202  * This function will search any VTIMEZONE subcomponents to learn the
 203  * relevant timezone information.
 204  */
 205 void ical_dezonify(icalcomponent *cal) {
 206         icalcomponent *vt = NULL;
 207
 208         /* lprintf(9, "ical_dezonify() started\n"); */
 209
 210         /* Convert all times to UTC */
 211         ical_dezonify_recurse(cal, cal);
 212
 213         /* Strip out VTIMEZONE subcomponents -- we don't need them anymore */
 214         while (vt = icalcomponent_get_first_component(
 215                         cal, ICAL_VTIMEZONE_COMPONENT), vt != NULL) {
 216                 icalcomponent_remove_component(cal, vt);
 217                 icalcomponent_free(vt);
 218         }
 219
 220         /* lprintf(9, "ical_dezonify() completed\n"); */
 221 }
 222
 223
 224 #endif /* WEBCIT_WITH_CALENDAR_SERVICE */