1 | /* date.c: date parsing for Subversion |
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2 | * |
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3 | * ==================================================================== |
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4 | * Copyright (c) 2000-2004 CollabNet. All rights reserved. |
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5 | * |
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6 | * This software is licensed as described in the file COPYING, which |
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7 | * you should have received as part of this distribution. The terms |
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8 | * are also available at http://subversion.tigris.org/license-1.html. |
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9 | * If newer versions of this license are posted there, you may use a |
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10 | * newer version instead, at your option. |
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11 | * |
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12 | * This software consists of voluntary contributions made by many |
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13 | * individuals. For exact contribution history, see the revision |
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14 | * history and logs, available at http://subversion.tigris.org/. |
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15 | * ==================================================================== |
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16 | */ |
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17 | |
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18 | #include "svn_time.h" |
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19 | #include "svn_error.h" |
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20 | |
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21 | #include "svn_private_config.h" |
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22 | |
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23 | /* Valid rule actions */ |
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24 | enum rule_action { |
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25 | ACCUM, /* Accumulate a decimal value */ |
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26 | MICRO, /* Accumulate microseconds */ |
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27 | TZIND, /* Handle +, -, Z */ |
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28 | NOOP, /* Do nothing */ |
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29 | SKIPFROM, /* If at end-of-value, accept the match. Otherwise, |
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30 | if the next template character matches the current |
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31 | value character, continue processing as normal. |
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32 | Otherwise, attempt to complete matching starting |
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33 | immediately after the first subsequent occurrance of |
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34 | ']' in the template. */ |
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35 | SKIP, /* Ignore this template character */ |
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36 | ACCEPT /* Accept the value */ |
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37 | }; |
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38 | |
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39 | /* How to handle a particular character in a template */ |
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40 | typedef struct |
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41 | { |
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42 | char key; /* The template char that this rule matches */ |
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43 | const char *valid; /* String of valid chars for this rule */ |
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44 | enum rule_action action; /* What action to take when the rule is matched */ |
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45 | int offset; /* Where to store the any results of the action, |
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46 | expressed in terms of bytes relative to the |
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47 | base of a match_state object. */ |
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48 | } rule; |
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49 | |
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50 | /* The parsed values, before localtime/gmt processing */ |
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51 | typedef struct |
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52 | { |
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53 | apr_time_exp_t base; |
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54 | apr_int32_t offhours; |
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55 | apr_int32_t offminutes; |
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56 | } match_state; |
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57 | |
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58 | #define DIGITS "0123456789" |
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59 | |
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60 | /* A declarative specification of how each template character |
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61 | should be processed, using a rule for each valid symbol. */ |
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62 | static const rule |
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63 | rules[] = |
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64 | { |
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65 | { 'Y', DIGITS, ACCUM, APR_OFFSETOF(match_state, base.tm_year) }, |
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66 | { 'M', DIGITS, ACCUM, APR_OFFSETOF(match_state, base.tm_mon) }, |
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67 | { 'D', DIGITS, ACCUM, APR_OFFSETOF(match_state, base.tm_mday) }, |
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68 | { 'h', DIGITS, ACCUM, APR_OFFSETOF(match_state, base.tm_hour) }, |
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69 | { 'm', DIGITS, ACCUM, APR_OFFSETOF(match_state, base.tm_min) }, |
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70 | { 's', DIGITS, ACCUM, APR_OFFSETOF(match_state, base.tm_sec) }, |
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71 | { 'u', DIGITS, MICRO, APR_OFFSETOF(match_state, base.tm_usec) }, |
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72 | { 'O', DIGITS, ACCUM, APR_OFFSETOF(match_state, offhours) }, |
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73 | { 'o', DIGITS, ACCUM, APR_OFFSETOF(match_state, offminutes) }, |
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74 | { '+', "-+", TZIND, 0 }, |
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75 | { 'Z', "Z", TZIND, 0 }, |
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76 | { ':', ":", NOOP, 0 }, |
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77 | { '-', "-", NOOP, 0 }, |
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78 | { 'T', "T", NOOP, 0 }, |
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79 | { ' ', " ", NOOP, 0 }, |
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80 | { '.', ".,", NOOP, 0 }, |
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81 | { '[', NULL, SKIPFROM, 0 }, |
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82 | { ']', NULL, SKIP, 0 }, |
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83 | { '\0', NULL, ACCEPT, 0 }, |
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84 | }; |
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85 | |
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86 | /* Return the rule associated with TCHAR, or NULL if there |
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87 | is no such rule. */ |
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88 | static const rule * |
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89 | find_rule(char tchar) |
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90 | { |
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91 | int i = sizeof(rules)/sizeof(rules[0]); |
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92 | while (i--) |
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93 | if (rules[i].key == tchar) |
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94 | return &rules[i]; |
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95 | return NULL; |
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96 | } |
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97 | |
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98 | /* Attempt to match the date-string in VALUE to the provided TEMPLATE, |
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99 | using the rules defined above. Return TRUE on successful match, |
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100 | FALSE otherwise. On successful match, fill in *EXP with the |
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101 | matched values and set *LOCALTZ to TRUE if the local time zone |
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102 | should be used to interpret the match (i.e. if no time zone |
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103 | information was provided), or FALSE if not. */ |
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104 | static svn_boolean_t |
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105 | template_match(apr_time_exp_t *expt, svn_boolean_t *localtz, |
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106 | const char *template, const char *value) |
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107 | { |
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108 | int multiplier = 100000; |
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109 | int tzind = 0; |
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110 | match_state ms; |
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111 | char *base = (char *)&ms; |
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112 | |
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113 | memset(&ms, 0, sizeof(ms)); |
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114 | |
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115 | for (;;) |
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116 | { |
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117 | const rule *match = find_rule(*template++); |
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118 | char vchar = *value++; |
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119 | apr_int32_t *place; |
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120 | |
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121 | if (!match || (match->valid |
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122 | && (!vchar || !strchr(match->valid, vchar)))) |
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123 | return FALSE; |
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124 | |
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125 | /* Compute the address of memory location affected by this |
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126 | rule by adding match->offset bytes to the address of ms. |
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127 | Because this is a byte-quantity, it is necessary to cast |
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128 | &ms to char *. */ |
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129 | place = (apr_int32_t *)(base + match->offset); |
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130 | switch (match->action) |
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131 | { |
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132 | case ACCUM: |
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133 | *place = *place * 10 + vchar - '0'; |
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134 | continue; |
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135 | case MICRO: |
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136 | *place += (vchar - '0') * multiplier; |
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137 | multiplier /= 10; |
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138 | continue; |
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139 | case TZIND: |
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140 | tzind = vchar; |
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141 | continue; |
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142 | case SKIP: |
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143 | value--; |
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144 | continue; |
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145 | case NOOP: |
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146 | continue; |
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147 | case SKIPFROM: |
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148 | if (!vchar) |
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149 | break; |
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150 | match = find_rule(*template); |
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151 | if (!strchr(match->valid, vchar)) |
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152 | template = strchr(template, ']') + 1; |
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153 | value--; |
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154 | continue; |
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155 | case ACCEPT: |
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156 | if (vchar) |
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157 | return FALSE; |
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158 | break; |
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159 | } |
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160 | |
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161 | break; |
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162 | } |
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163 | |
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164 | /* Validate gmt offset here, since we can't reliably do it later. */ |
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165 | if (ms.offhours > 23 || ms.offminutes > 59) |
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166 | return FALSE; |
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167 | |
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168 | /* tzind will be '+' or '-' for an explicit time zone, 'Z' to |
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169 | indicate UTC, or 0 to indicate local time. */ |
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170 | switch (tzind) |
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171 | { |
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172 | case '+': |
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173 | ms.base.tm_gmtoff = ms.offhours * 3600 + ms.offminutes * 60; |
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174 | break; |
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175 | case '-': |
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176 | ms.base.tm_gmtoff = -(ms.offhours * 3600 + ms.offminutes * 60); |
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177 | break; |
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178 | } |
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179 | |
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180 | *expt = ms.base; |
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181 | *localtz = (tzind == 0); |
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182 | return TRUE; |
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183 | } |
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184 | |
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185 | static int |
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186 | valid_days_by_month[] = { |
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187 | 31, 29, 31, 30, |
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188 | 31, 30, 31, 31, |
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189 | 30, 31, 30, 31 |
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190 | }; |
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191 | |
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192 | svn_error_t * |
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193 | svn_parse_date(svn_boolean_t *matched, apr_time_t *result, const char *text, |
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194 | apr_time_t now, apr_pool_t *pool) |
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195 | { |
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196 | apr_time_exp_t expt, expnow; |
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197 | apr_status_t apr_err; |
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198 | svn_boolean_t localtz; |
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199 | |
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200 | *matched = FALSE; |
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201 | |
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202 | apr_err = apr_time_exp_lt(&expnow, now); |
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203 | if (apr_err != APR_SUCCESS) |
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204 | return svn_error_wrap_apr(apr_err, _("Can't manipulate current date")); |
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205 | |
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206 | if (template_match(&expt, &localtz, /* ISO-8601 extended, date only */ |
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207 | "YYYY-M[M]-D[D]", |
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208 | text) |
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209 | || template_match(&expt, &localtz, /* ISO-8601 extended, UTC */ |
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210 | "YYYY-M[M]-D[D]Th[h]:mm[:ss[.u[u[u[u[u[u][Z]", |
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211 | text) |
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212 | || template_match(&expt, &localtz, /* ISO-8601 extended, with offset */ |
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213 | "YYYY-M[M]-D[D]Th[h]:mm[:ss[.u[u[u[u[u[u]+OO[:oo]", |
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214 | text) |
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215 | || template_match(&expt, &localtz, /* ISO-8601 basic, date only */ |
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216 | "YYYYMMDD", |
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217 | text) |
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218 | || template_match(&expt, &localtz, /* ISO-8601 basic, UTC */ |
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219 | "YYYYMMDDThhmm[ss[.u[u[u[u[u[u][Z]", |
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220 | text) |
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221 | || template_match(&expt, &localtz, /* ISO-8601 basic, with offset */ |
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222 | "YYYYMMDDThhmm[ss[.u[u[u[u[u[u]+OO[oo]", |
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223 | text) |
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224 | || template_match(&expt, &localtz, /* "svn log" format */ |
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225 | "YYYY-M[M]-D[D] h[h]:mm[:ss[.u[u[u[u[u[u][ +OO[oo]", |
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226 | text) |
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227 | || template_match(&expt, &localtz, /* GNU date's iso-8601 */ |
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228 | "YYYY-M[M]-D[D]Th[h]:mm[:ss[.u[u[u[u[u[u]+OO[oo]", |
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229 | text)) |
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230 | { |
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231 | expt.tm_year -= 1900; |
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232 | expt.tm_mon -= 1; |
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233 | } |
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234 | else if (template_match(&expt, &localtz, /* Just a time */ |
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235 | "h[h]:mm[:ss[.u[u[u[u[u[u]", |
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236 | text)) |
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237 | { |
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238 | expt.tm_year = expnow.tm_year; |
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239 | expt.tm_mon = expnow.tm_mon; |
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240 | expt.tm_mday = expnow.tm_mday; |
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241 | } |
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242 | else |
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243 | return SVN_NO_ERROR; |
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244 | |
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245 | /* Range validation, allowing for leap seconds */ |
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246 | if (expt.tm_mon < 0 || expt.tm_mon > 11 |
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247 | || expt.tm_mday > valid_days_by_month[expt.tm_mon] |
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248 | || expt.tm_mday < 1 |
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249 | || expt.tm_hour > 23 |
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250 | || expt.tm_min > 59 |
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251 | || expt.tm_sec > 60) |
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252 | return SVN_NO_ERROR; |
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253 | |
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254 | /* february/leap-year day checking. tm_year is bias-1900, so centuries |
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255 | that equal 100 (mod 400) are multiples of 400. */ |
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256 | if (expt.tm_mon == 1 |
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257 | && expt.tm_mday == 29 |
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258 | && (expt.tm_year % 4 != 0 |
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259 | || (expt.tm_year % 100 == 0 && expt.tm_year % 400 != 100))) |
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260 | return SVN_NO_ERROR; |
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261 | |
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262 | if (localtz) |
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263 | { |
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264 | apr_time_t candidate; |
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265 | apr_time_exp_t expthen; |
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266 | |
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267 | /* We need to know the GMT offset of the requested time, not the |
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268 | current time. In some cases, that quantity is ambiguous, |
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269 | since at the end of daylight saving's time, an hour's worth |
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270 | of local time happens twice. For those cases, we should |
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271 | prefer DST if we are currently in DST, and standard time if |
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272 | not. So, calculate the time value using the current time's |
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273 | GMT offset and use the GMT offset of the resulting time. */ |
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274 | expt.tm_gmtoff = expnow.tm_gmtoff; |
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275 | apr_err = apr_time_exp_gmt_get(&candidate, &expt); |
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276 | if (apr_err != APR_SUCCESS) |
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277 | return svn_error_wrap_apr(apr_err, |
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278 | _("Can't calculate requested date")); |
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279 | apr_err = apr_time_exp_lt(&expthen, candidate); |
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280 | if (apr_err != APR_SUCCESS) |
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281 | return svn_error_wrap_apr(apr_err, _("Can't expand time")); |
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282 | expt.tm_gmtoff = expthen.tm_gmtoff; |
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283 | } |
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284 | apr_err = apr_time_exp_gmt_get(result, &expt); |
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285 | if (apr_err != APR_SUCCESS) |
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286 | return svn_error_wrap_apr(apr_err, _("Can't calculate requested date")); |
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287 | |
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288 | *matched = TRUE; |
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289 | return SVN_NO_ERROR; |
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290 | } |
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