subversion/libsvn_subr/time.c

   1 /*
   2  * time.c:  time/date utilities
   3  *
   4  * ====================================================================
   5  * Copyright (c) 2000-2007 CollabNet.  All rights reserved.
   6  *
   7  * This software is licensed as described in the file COPYING, which
   8  * you should have received as part of this distribution.  The terms
   9  * are also available at http://subversion.tigris.org/license-1.html.
  10  * If newer versions of this license are posted there, you may use a
  11  * newer version instead, at your option.
  12  *
  13  * This software consists of voluntary contributions made by many
  14  * individuals.  For exact contribution history, see the revision
  15  * history and logs, available at http://subversion.tigris.org/.
  16  * ====================================================================
  17  */
  18
  19
  20 \f
  21 #include <string.h>
  22 #include <stdlib.h>
  23 #include <apr_pools.h>
  24 #include <apr_time.h>
  25 #include <apr_strings.h>
  26 #include "svn_time.h"
  27 #include "svn_utf.h"
  28 #include "svn_error.h"
  29 #include "svn_private_config.h"
  30
  31
  32 \f
  33 /*** Code. ***/
  34
  35 /* Our timestamp strings look like this:
  36  *
  37  *    "2002-05-07Thh:mm:ss.uuuuuuZ"
  38  *
  39  * The format is conformant with ISO-8601 and the date format required
  40  * by RFC2518 for creationdate. It is a direct conversion between
  41  * apr_time_t and a string, so converting to string and back retains
  42  * the exact value.
  43  */
  44 static const char * const timestamp_format =
  45 "%04d-%02d-%02dT%02d:%02d:%02d.%06dZ";
  46
  47 /* Our old timestamp strings looked like this:
  48  *
  49  *    "Tue 3 Oct 2000 HH:MM:SS.UUU (day 277, dst 1, gmt_off -18000)"
  50  *
  51  * The idea is that they are conventionally human-readable for the
  52  * first part, and then in parentheses comes everything else required
  53  * to completely fill in an apr_time_exp_t: tm_yday, tm_isdst,
  54  * and tm_gmtoff.
  55  *
  56  * This format is still recognized on input, for backward
  57  * compatibility, but no longer generated.
  58  */
  59 static const char * const old_timestamp_format =
  60 "%3s %d %3s %d %02d:%02d:%02d.%06d (day %03d, dst %d, gmt_off %06d)";
  61
  62 /* Our human representation of dates looks like this:
  63  *
  64  *    "2002-06-23 11:13:02 +0300 (Sun, 23 Jun 2002)"
  65  *
  66  * This format is used whenever time is shown to the user. It consists
  67  * of a machine parseable, almost ISO-8601, part in the beginning -
  68  * and a human explanatory part at the end. The machine parseable part
  69  * is generated strictly by APR and our code, with a apr_snprintf. The
  70  * human explanatory part is generated by apr_strftime, which means
  71  * that its generation can be affected by locale, it can fail and it
  72  * doesn't need to be constant in size. In other words, perfect to be
  73  * converted to a configuration option later on.
  74  */
  75 /* Maximum length for the date string. */
  76 #define SVN_TIME__MAX_LENGTH 80
  77 /* Machine parseable part, generated by apr_snprintf. */
  78 static const char * const human_timestamp_format =
  79 "%.4d-%.2d-%.2d %.2d:%.2d:%.2d %+.2d%.2d";
  80 /* Human explanatory part, generated by apr_strftime as "Sat, 01 Jan 2000" */
  81 #define human_timestamp_format_suffix _(" (%a, %d %b %Y)")
  82
  83 #define SVN_SLEEP_ENV_VAR "SVN_I_LOVE_CORRUPTED_WORKING_COPIES_SO_DISABLE_SLEEP_FOR_TIMESTAMPS"
  84
  85 const char *
  86 svn_time_to_cstring(apr_time_t when, apr_pool_t *pool)
  87 {
  88   const char *t_cstr;
  89   apr_time_exp_t exploded_time;
  90
  91   /* We toss apr_status_t return value here -- for one thing, caller
  92      should pass in good information.  But also, where APR's own code
  93      calls these functions it tosses the return values, and
  94      furthermore their current implementations can only return success
  95      anyway. */
  96
  97   /* We get the date in GMT now -- and expect the tm_gmtoff and
  98      tm_isdst to be not set. We also ignore the weekday and yearday,
  99      since those are not needed. */
 100
 101   apr_time_exp_gmt(&exploded_time, when);
 102
 103   /* It would be nice to use apr_strftime(), but APR doesn't give a
 104      way to convert back, so we wouldn't be able to share the format
 105      string between the writer and reader. */
 106   t_cstr = apr_psprintf(pool,
 107                         timestamp_format,
 108                         exploded_time.tm_year + 1900,
 109                         exploded_time.tm_mon + 1,
 110                         exploded_time.tm_mday,
 111                         exploded_time.tm_hour,
 112                         exploded_time.tm_min,
 113                         exploded_time.tm_sec,
 114                         exploded_time.tm_usec);
 115
 116   /* ### Remove this when the old style timestamp parsing is taken
 117      out.
 118   t_cstr = apr_psprintf (pool,
 119                          old_timestamp_format,
 120                          apr_day_snames[exploded_time.tm_wday],
 121                          exploded_time.tm_mday,
 122                          apr_month_snames[exploded_time.tm_mon],
 123                          exploded_time.tm_year + 1900,
 124                          exploded_time.tm_hour,
 125                          exploded_time.tm_min,
 126                          exploded_time.tm_sec,
 127                          exploded_time.tm_usec,
 128                          exploded_time.tm_yday + 1,
 129                          exploded_time.tm_isdst,
 130                          exploded_time.tm_gmtoff);
 131   */
 132
 133   return t_cstr;
 134 }
 135
 136
 137 static int
 138 find_matching_string(char *str, apr_size_t size, const char strings[][4])
 139 {
 140   apr_size_t i;
 141
 142   for (i = 0; i < size; i++)
 143     if (strings[i] && (strcmp(str, strings[i]) == 0))
 144       return i;
 145
 146   return -1;
 147 }
 148
 149
 150 svn_error_t *
 151 svn_time_from_cstring(apr_time_t *when, const char *data, apr_pool_t *pool)
 152 {
 153   apr_time_exp_t exploded_time;
 154   apr_status_t apr_err;
 155   char wday[4], month[4];
 156   char *c;
 157
 158   /* Open-code parsing of the new timestamp format, as this
 159      is a hot path for reading the entries file.  This format looks
 160      like:  "2001-08-31T04:24:14.966996Z"  */
 161   exploded_time.tm_year = strtol(data, &c, 10);
 162   if (*c++ != '-') goto fail;
 163   exploded_time.tm_mon = strtol(c, &c, 10);
 164   if (*c++ != '-') goto fail;
 165   exploded_time.tm_mday = strtol(c, &c, 10);
 166   if (*c++ != 'T') goto fail;
 167   exploded_time.tm_hour = strtol(c, &c, 10);
 168   if (*c++ != ':') goto fail;
 169   exploded_time.tm_min = strtol(c, &c, 10);
 170   if (*c++ != ':') goto fail;
 171   exploded_time.tm_sec = strtol(c, &c, 10);
 172   if (*c++ != '.') goto fail;
 173   exploded_time.tm_usec = strtol(c, &c, 10);
 174   if (*c++ != 'Z') goto fail;
 175
 176   exploded_time.tm_year  -= 1900;
 177   exploded_time.tm_mon   -= 1;
 178   exploded_time.tm_wday   = 0;
 179   exploded_time.tm_yday   = 0;
 180   exploded_time.tm_isdst  = 0;
 181   exploded_time.tm_gmtoff = 0;
 182
 183   apr_err = apr_time_exp_gmt_get(when, &exploded_time);
 184   if (apr_err == APR_SUCCESS)
 185     return SVN_NO_ERROR;
 186
 187   return svn_error_create(SVN_ERR_BAD_DATE, NULL, NULL);
 188
 189  fail:
 190   /* Try the compatibility option.  This does not need to be fast,
 191      as this format is no longer generated and the client will convert
 192      an old-format entries file the first time it reads it.  */
 193   if (sscanf(data,
 194              old_timestamp_format,
 195              wday,
 196              &exploded_time.tm_mday,
 197              month,
 198              &exploded_time.tm_year,
 199              &exploded_time.tm_hour,
 200              &exploded_time.tm_min,
 201              &exploded_time.tm_sec,
 202              &exploded_time.tm_usec,
 203              &exploded_time.tm_yday,
 204              &exploded_time.tm_isdst,
 205              &exploded_time.tm_gmtoff) == 11)
 206     {
 207       exploded_time.tm_year -= 1900;
 208       exploded_time.tm_yday -= 1;
 209       /* Using hard coded limits for the arrays - they are going away
 210          soon in any case. */
 211       exploded_time.tm_wday = find_matching_string(wday, 7, apr_day_snames);
 212       exploded_time.tm_mon = find_matching_string(month, 12, apr_month_snames);
 213
 214       apr_err = apr_time_exp_gmt_get(when, &exploded_time);
 215       if (apr_err != APR_SUCCESS)
 216         return svn_error_create(SVN_ERR_BAD_DATE, NULL, NULL);
 217
 218       return SVN_NO_ERROR;
 219     }
 220   /* Timestamp is something we do not recognize. */
 221   else
 222     return svn_error_create(SVN_ERR_BAD_DATE, NULL, NULL);
 223 }
 224
 225
 226 const char *
 227 svn_time_to_human_cstring(apr_time_t when, apr_pool_t *pool)
 228 {
 229   apr_time_exp_t exploded_time;
 230   apr_size_t len, retlen;
 231   apr_status_t ret;
 232   char *datestr, *curptr, human_datestr[SVN_TIME__MAX_LENGTH];
 233
 234   /* Get the time into parts */
 235   apr_time_exp_lt(&exploded_time, when);
 236
 237   /* Make room for datestring */
 238   datestr = apr_palloc(pool, SVN_TIME__MAX_LENGTH);
 239
 240   /* Put in machine parseable part */
 241   len = apr_snprintf(datestr,
 242                      SVN_TIME__MAX_LENGTH,
 243                      human_timestamp_format,
 244                      exploded_time.tm_year + 1900,
 245                      exploded_time.tm_mon + 1,
 246                      exploded_time.tm_mday,
 247                      exploded_time.tm_hour,
 248                      exploded_time.tm_min,
 249                      exploded_time.tm_sec,
 250                      exploded_time.tm_gmtoff / (60 * 60),
 251                      (abs(exploded_time.tm_gmtoff) / 60) % 60);
 252
 253   /* If we overfilled the buffer, just return what we got. */
 254   if (len >= SVN_TIME__MAX_LENGTH)
 255     return datestr;
 256
 257   /* Calculate offset to the end of the machine parseable part. */
 258   curptr = datestr + len;
 259
 260   /* Put in human explanatory part */
 261   ret = apr_strftime(human_datestr,
 262                      &retlen,
 263                      SVN_TIME__MAX_LENGTH - len,
 264                      human_timestamp_format_suffix,
 265                      &exploded_time);
 266
 267   /* If there was an error, ensure that the string is zero-terminated. */
 268   if (ret || retlen == 0)
 269     *curptr = '\0';
 270   else
 271     {
 272       const char *utf8_string;
 273       svn_error_t *err;
 274
 275       err = svn_utf_cstring_to_utf8(&utf8_string, human_datestr, pool);
 276       if (err)
 277         {
 278           *curptr = '\0';
 279           svn_error_clear(err);
 280         }
 281       else
 282         apr_cpystrn(curptr, utf8_string, SVN_TIME__MAX_LENGTH - len);
 283     }
 284
 285   return datestr;
 286 }
 287
 288
 289 void
 290 svn_sleep_for_timestamps(void)
 291 {
 292   apr_time_t now, then;
 293   char *sleep_env_var;
 294
 295   sleep_env_var = getenv(SVN_SLEEP_ENV_VAR);
 296
 297   /* Sleep until the next second tick, plus a tenth of a second for margin. */
 298   if (! sleep_env_var || apr_strnatcasecmp(sleep_env_var, "yes") != 0)
 299     {
 300       now = apr_time_now();
 301       then = apr_time_make(apr_time_sec(now) + 1, APR_USEC_PER_SEC / 10);
 302       apr_sleep(then - now);
 303     }
 304 }