webcit/ical_dezonify.c

   1 /*
   2  * $Id$
   3  *
   4  * Function to go through an ical component set and convert all non-UTC
   5  * date/time properties to UTC.  It also strips out any VTIMEZONE
   6  * subcomponents afterwards, because they're irrelevant.
   7  *
   8  * Everything here will work on both a fully encapsulated VCALENDAR component
   9  * or any type of subcomponent.
  10  *
  11  */
  12
  13 #include "webcit.h"
  14 #include "webserver.h"
  15
  16 /*
  17  * Figure out which time zone needs to be used for timestamps that are
  18  * not UTC and do not have a time zone specified.
  19  *
  20  */
  21 icaltimezone *get_default_icaltimezone(void) {
  22
  23         icaltimezone *zone = NULL;
  24         const char *default_zone_name = ChrPtr(WC->serv_info->serv_default_cal_zone);
  25
  26         if (!zone) {
  27                 zone = icaltimezone_get_builtin_timezone(default_zone_name);
  28         }
  29         if (!zone) {
  30                 lprintf(1, "Unable to load '%s' time zone.  Defaulting to UTC.\n", default_zone_name);
  31                 zone = icaltimezone_get_utc_timezone();
  32         }
  33         if (!zone) {
  34                 lprintf(1, "Unable to load UTC time zone!\n");
  35         }
  36         return zone;
  37 }
  38
  39
  40 /*
  41  * Back end function for ical_dezonify()
  42  *
  43  * We supply this with the master component, the relevant component,
  44  * and the property (which will be a DTSTART, DTEND, etc.)
  45  * which we want to convert to UTC.
  46  */
  47 void ical_dezonify_backend(icalcomponent *cal,
  48                         icalcomponent *rcal,
  49                         icalproperty *prop) {
  50
  51         icaltimezone *t = NULL;
  52         icalparameter *param;
  53         const char *tzid = NULL;
  54         struct icaltimetype TheTime;
  55         int utc_declared_as_tzid = 0;   /* Component declared 'TZID=GMT' instead of using Z syntax */
  56
  57         /* Give me nothing and I will give you nothing in return. */
  58         if (cal == NULL) return;
  59
  60         /* Hunt for a TZID parameter in this property. */
  61         param = icalproperty_get_first_parameter(prop, ICAL_TZID_PARAMETER);
  62
  63         /* Get the stringish name of this TZID. */
  64         if (param != NULL) {
  65                 tzid = icalparameter_get_tzid(param);
  66
  67                 /* Convert it to an icaltimezone type. */
  68                 if (tzid != NULL) {
  69 #ifdef DBG_ICAL
  70                         lprintf(9, "                * Stringy supplied timezone is: '%s'\n", tzid);
  71 #endif
  72                         if ( (!strcasecmp(tzid, "UTC")) || (!strcasecmp(tzid, "GMT")) ) {
  73                                 utc_declared_as_tzid = 1;
  74 #ifdef DBG_ICAL
  75                                 lprintf(9, "                * ...and we handle that internally.\n");
  76 #endif
  77                         }
  78                         else {
  79                                 /* try attached first */
  80                                 t = icalcomponent_get_timezone(cal, tzid);
  81 #ifdef DBG_ICAL
  82                                 lprintf(9, "                * ...and I %s have tzdata for that zone.\n",
  83                                         (t ? "DO" : "DO NOT")
  84                                 );
  85 #endif
  86                                 /* then try built-in timezones */
  87                                 if (!t) {
  88                                         t = icaltimezone_get_builtin_timezone(tzid);
  89 #ifdef DBG_ICAL
  90                                         if (t) {
  91                                                 lprintf(9, "                * Using system tzdata!\n");
  92                                         }
  93 #endif
  94                                 }
  95                         }
  96                 }
  97
  98         }
  99
 100         /* Now we know the timezone.  Convert to UTC. */
 101
 102         if (icalproperty_isa(prop) == ICAL_DTSTART_PROPERTY) {
 103                 TheTime = icalproperty_get_dtstart(prop);
 104         }
 105         else if (icalproperty_isa(prop) == ICAL_DTEND_PROPERTY) {
 106                 TheTime = icalproperty_get_dtend(prop);
 107         }
 108         else if (icalproperty_isa(prop) == ICAL_DUE_PROPERTY) {
 109                 TheTime = icalproperty_get_due(prop);
 110         }
 111         else if (icalproperty_isa(prop) == ICAL_EXDATE_PROPERTY) {
 112                 TheTime = icalproperty_get_exdate(prop);
 113         }
 114         else {
 115                 return;
 116         }
 117
 118 #ifdef DBG_ICAL
 119         lprintf(9, "                * Was: %s\n", icaltime_as_ical_string(TheTime));
 120 #endif
 121
 122         if (TheTime.is_utc) {
 123 #ifdef DBG_ICAL
 124                 lprintf(9, "                * This property is ALREADY UTC.\n");
 125 #endif
 126         }
 127
 128         else if (utc_declared_as_tzid) {
 129 #ifdef DBG_ICAL
 130                 lprintf(9, "                * Replacing '%s' TZID with 'Z' suffix.\n", tzid);
 131 #endif
 132                 TheTime.is_utc = 1;
 133         }
 134
 135         else {
 136                 /* Do the conversion. */
 137                 if (t != NULL) {
 138 #ifdef DBG_ICAL
 139                         lprintf(9, "                * Timezone prop found.  Converting to UTC.\n");
 140 #endif
 141                 }
 142                 else {
 143 #ifdef DBG_ICAL
 144                         lprintf(9, "                * Converting default timezone to UTC.\n");
 145 #endif
 146                 }
 147
 148                 if (t == NULL) {
 149                         t = get_default_icaltimezone();
 150                 }
 151                 icaltimezone_convert_time(&TheTime, t, icaltimezone_get_utc_timezone());
 152                 TheTime.is_utc = 1;
 153         }
 154
 155         icalproperty_remove_parameter_by_kind(prop, ICAL_TZID_PARAMETER);
 156 #ifdef DBG_ICAL
 157         lprintf(9, "                * Now: %s\n", icaltime_as_ical_string(TheTime));
 158 #endif
 159
 160         /* Now add the converted property back in. */
 161         if (icalproperty_isa(prop) == ICAL_DTSTART_PROPERTY) {
 162                 icalproperty_set_dtstart(prop, TheTime);
 163         }
 164         else if (icalproperty_isa(prop) == ICAL_DTEND_PROPERTY) {
 165                 icalproperty_set_dtend(prop, TheTime);
 166         }
 167         else if (icalproperty_isa(prop) == ICAL_DUE_PROPERTY) {
 168                 icalproperty_set_due(prop, TheTime);
 169         }
 170         else if (icalproperty_isa(prop) == ICAL_EXDATE_PROPERTY) {
 171                 icalproperty_set_exdate(prop, TheTime);
 172         }
 173 }
 174
 175
 176 /*
 177  * Recursive portion of ical_dezonify()
 178  */
 179 void ical_dezonify_recurse(icalcomponent *cal, icalcomponent *rcal) {
 180         icalcomponent *c;
 181         icalproperty *p;
 182
 183         /*
 184          * Recurse through all subcomponents *except* VTIMEZONE ones.
 185          */
 186         for (c=icalcomponent_get_first_component(
 187                                         rcal, ICAL_ANY_COMPONENT);
 188                 c != NULL;
 189                 c = icalcomponent_get_next_component(
 190                                         rcal, ICAL_ANY_COMPONENT)
 191         ) {
 192                 if (icalcomponent_isa(c) != ICAL_VTIMEZONE_COMPONENT) {
 193                         ical_dezonify_recurse(cal, c);
 194                 }
 195         }
 196
 197         /*
 198          * Now look for DTSTART and DTEND properties
 199          */
 200         for (p=icalcomponent_get_first_property(rcal, ICAL_ANY_PROPERTY);
 201                 p != NULL;
 202                 p = icalcomponent_get_next_property(rcal, ICAL_ANY_PROPERTY)
 203         ) {
 204                 if (
 205                         (icalproperty_isa(p) == ICAL_DTSTART_PROPERTY)
 206                         || (icalproperty_isa(p) == ICAL_DTEND_PROPERTY)
 207                         || (icalproperty_isa(p) == ICAL_DUE_PROPERTY)
 208                         || (icalproperty_isa(p) == ICAL_EXDATE_PROPERTY)
 209                    ) {
 210                         ical_dezonify_backend(cal, rcal, p);
 211                 }
 212         }
 213 }
 214
 215
 216 /*
 217  * Convert all DTSTART and DTEND properties in all subcomponents to UTC.
 218  * This function will search any VTIMEZONE subcomponents to learn the
 219  * relevant timezone information.
 220  */
 221 void ical_dezonify(icalcomponent *cal) {
 222         icalcomponent *vt = NULL;
 223
 224 #ifdef DBG_ICAL
 225         lprintf(9, "ical_dezonify() started\n");
 226 #endif
 227
 228         /* Convert all times to UTC */
 229         ical_dezonify_recurse(cal, cal);
 230
 231         /* Strip out VTIMEZONE subcomponents -- we don't need them anymore */
 232         while (vt = icalcomponent_get_first_component(
 233                         cal, ICAL_VTIMEZONE_COMPONENT), vt != NULL) {
 234                 icalcomponent_remove_component(cal, vt);
 235                 icalcomponent_free(vt);
 236         }
 237
 238 #ifdef DBG_ICAL
 239         lprintf(9, "ical_dezonify() completed\n");
 240 #endif
 241 }
 242