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