citadel/ical_dezonify.c

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