line-range.c

   1 #include "git-compat-util.h"
   2 #include "line-range.h"
   3 #include "xdiff-interface.h"
   4 #include "strbuf.h"
   5 #include "userdiff.h"
   6
   7 /*
   8  * Parse one item in the -L option
   9  *
  10  * 'begin' is applicable only to relative range anchors. Absolute anchors
  11  * ignore this value.
  12  *
  13  * When parsing "-L A,B", parse_loc() is called once for A and once for B.
  14  *
  15  * When parsing A, 'begin' must be a negative number, the absolute value of
  16  * which is the line at which relative start-of-range anchors should be
  17  * based. Beginning of file is represented by -1.
  18  *
  19  * When parsing B, 'begin' must be the positive line number immediately
  20  * following the line computed for 'A'.
  21  */
  22 static const char *parse_loc(const char *spec, nth_line_fn_t nth_line,
  23                              void *data, long lines, long begin, long *ret)
  24 {
  25         char *term;
  26         const char *line;
  27         long num;
  28         int reg_error;
  29         regex_t regexp;
  30         regmatch_t match[1];
  31
  32         /* Allow "-L <something>,+20" to mean starting at <something>
  33          * for 20 lines, or "-L <something>,-5" for 5 lines ending at
  34          * <something>.
  35          */
  36         if (1 <= begin && (spec[0] == '+' || spec[0] == '-')) {
  37                 num = strtol(spec + 1, &term, 10);
  38                 if (term != spec + 1) {
  39                         if (!ret)
  40                                 return term;
  41                         if (num == 0)
  42                                 die("-L invalid empty range");
  43                         if (spec[0] == '-')
  44                                 num = 0 - num;
  45                         if (0 < num)
  46                                 *ret = begin + num - 2;
  47                         else if (!num)
  48                                 *ret = begin;
  49                         else
  50                                 *ret = begin + num;
  51                         return term;
  52                 }
  53                 return spec;
  54         }
  55         num = strtol(spec, &term, 10);
  56         if (term != spec) {
  57                 if (ret)
  58                         *ret = num;
  59                 return term;
  60         }
  61
  62         if (begin < 0) {
  63                 if (spec[0] != '^')
  64                         begin = -begin;
  65                 else {
  66                         begin = 1;
  67                         spec++;
  68                 }
  69         }
  70
  71         if (spec[0] != '/')
  72                 return spec;
  73
  74         /* it could be a regexp of form /.../ */
  75         for (term = (char *) spec + 1; *term && *term != '/'; term++) {
  76                 if (*term == '\\')
  77                         term++;
  78         }
  79         if (*term != '/')
  80                 return spec;
  81
  82         /* in the scan-only case we are not interested in the regex */
  83         if (!ret)
  84                 return term+1;
  85
  86         /* try [spec+1 .. term-1] as regexp */
  87         *term = 0;
  88         begin--; /* input is in human terms */
  89         line = nth_line(data, begin);
  90
  91         if (!(reg_error = regcomp(&regexp, spec + 1, REG_NEWLINE)) &&
  92             !(reg_error = regexec(&regexp, line, 1, match, 0))) {
  93                 const char *cp = line + match[0].rm_so;
  94                 const char *nline;
  95
  96                 while (begin++ < lines) {
  97                         nline = nth_line(data, begin);
  98                         if (line <= cp && cp < nline)
  99                                 break;
 100                         line = nline;
 101                 }
 102                 *ret = begin;
 103                 regfree(&regexp);
 104                 *term++ = '/';
 105                 return term;
 106         }
 107         else {
 108                 char errbuf[1024];
 109                 regerror(reg_error, &regexp, errbuf, 1024);
 110                 die("-L parameter '%s' starting at line %ld: %s",
 111                     spec + 1, begin + 1, errbuf);
 112         }
 113 }
 114
 115 static int match_funcname(xdemitconf_t *xecfg, const char *bol, const char *eol)
 116 {
 117         if (xecfg) {
 118                 char buf[1];
 119                 return xecfg->find_func(bol, eol - bol, buf, 1,
 120                                         xecfg->find_func_priv) >= 0;
 121         }
 122
 123         if (bol == eol)
 124                 return 0;
 125         if (isalpha(*bol) || *bol == '_' || *bol == '$')
 126                 return 1;
 127         return 0;
 128 }
 129
 130 static const char *find_funcname_matching_regexp(xdemitconf_t *xecfg, const char *start,
 131                                                  regex_t *regexp)
 132 {
 133         int reg_error;
 134         regmatch_t match[1];
 135         while (1) {
 136                 const char *bol, *eol;
 137                 reg_error = regexec(regexp, start, 1, match, 0);
 138                 if (reg_error == REG_NOMATCH)
 139                         return NULL;
 140                 else if (reg_error) {
 141                         char errbuf[1024];
 142                         regerror(reg_error, regexp, errbuf, 1024);
 143                         die("-L parameter: regexec() failed: %s", errbuf);
 144                 }
 145                 /* determine extent of line matched */
 146                 bol = start+match[0].rm_so;
 147                 eol = start+match[0].rm_eo;
 148                 while (bol > start && *bol != '\n')
 149                         bol--;
 150                 if (*bol == '\n')
 151                         bol++;
 152                 while (*eol && *eol != '\n')
 153                         eol++;
 154                 if (*eol == '\n')
 155                         eol++;
 156                 /* is it a funcname line? */
 157                 if (match_funcname(xecfg, (char*) bol, (char*) eol))
 158                         return bol;
 159                 start = eol;
 160         }
 161 }
 162
 163 static const char *parse_range_funcname(const char *arg, nth_line_fn_t nth_line_cb,
 164                                         void *cb_data, long lines, long anchor, long *begin, long *end,
 165                                         const char *path)
 166 {
 167         char *pattern;
 168         const char *term;
 169         struct userdiff_driver *drv;
 170         xdemitconf_t *xecfg = NULL;
 171         const char *start;
 172         const char *p;
 173         int reg_error;
 174         regex_t regexp;
 175
 176         if (*arg == '^') {
 177                 anchor = 1;
 178                 arg++;
 179         }
 180
 181         assert(*arg == ':');
 182         term = arg+1;
 183         while (*term && *term != ':') {
 184                 if (*term == '\\' && *(term+1))
 185                         term++;
 186                 term++;
 187         }
 188         if (term == arg+1)
 189                 return NULL;
 190         if (!begin) /* skip_range_arg case */
 191                 return term;
 192
 193         pattern = xstrndup(arg+1, term-(arg+1));
 194
 195         anchor--; /* input is in human terms */
 196         start = nth_line_cb(cb_data, anchor);
 197
 198         drv = userdiff_find_by_path(path);
 199         if (drv && drv->funcname.pattern) {
 200                 const struct userdiff_funcname *pe = &drv->funcname;
 201                 xecfg = xcalloc(1, sizeof(*xecfg));
 202                 xdiff_set_find_func(xecfg, pe->pattern, pe->cflags);
 203         }
 204
 205         reg_error = regcomp(&regexp, pattern, REG_NEWLINE);
 206         if (reg_error) {
 207                 char errbuf[1024];
 208                 regerror(reg_error, &regexp, errbuf, 1024);
 209                 die("-L parameter '%s': %s", pattern, errbuf);
 210         }
 211
 212         p = find_funcname_matching_regexp(xecfg, (char*) start, &regexp);
 213         if (!p)
 214                 die("-L parameter '%s' starting at line %ld: no match",
 215                     pattern, anchor + 1);
 216         *begin = 0;
 217         while (p > nth_line_cb(cb_data, *begin))
 218                 (*begin)++;
 219
 220         if (*begin >= lines)
 221                 die("-L parameter '%s' matches at EOF", pattern);
 222
 223         *end = *begin+1;
 224         while (*end < lines) {
 225                 const char *bol = nth_line_cb(cb_data, *end);
 226                 const char *eol = nth_line_cb(cb_data, *end+1);
 227                 if (match_funcname(xecfg, bol, eol))
 228                         break;
 229                 (*end)++;
 230         }
 231
 232         regfree(&regexp);
 233         free(xecfg);
 234         free(pattern);
 235
 236         /* compensate for 1-based numbering */
 237         (*begin)++;
 238
 239         return term;
 240 }
 241
 242 int parse_range_arg(const char *arg, nth_line_fn_t nth_line_cb,
 243                     void *cb_data, long lines, long anchor,
 244                     long *begin, long *end, const char *path)
 245 {
 246         *begin = *end = 0;
 247
 248         if (anchor < 1)
 249                 anchor = 1;
 250         if (anchor > lines)
 251                 anchor = lines + 1;
 252
 253         if (*arg == ':' || (*arg == '^' && *(arg + 1) == ':')) {
 254                 arg = parse_range_funcname(arg, nth_line_cb, cb_data, lines, anchor, begin, end, path);
 255                 if (!arg || *arg)
 256                         return -1;
 257                 return 0;
 258         }
 259
 260         arg = parse_loc(arg, nth_line_cb, cb_data, lines, -anchor, begin);
 261
 262         if (*arg == ',')
 263                 arg = parse_loc(arg + 1, nth_line_cb, cb_data, lines, *begin + 1, end);
 264
 265         if (*arg)
 266                 return -1;
 267
 268         if (*begin && *end && *end < *begin) {
 269                 long tmp;
 270                 tmp = *end; *end = *begin; *begin = tmp;
 271         }
 272
 273         return 0;
 274 }
 275
 276 const char *skip_range_arg(const char *arg)
 277 {
 278         if (*arg == ':' || (*arg == '^' && *(arg + 1) == ':'))
 279                 return parse_range_funcname(arg, NULL, NULL, 0, 0, NULL, NULL, NULL);
 280
 281         arg = parse_loc(arg, NULL, NULL, 0, -1, NULL);
 282
 283         if (*arg == ',')
 284                 arg = parse_loc(arg+1, NULL, NULL, 0, 0, NULL);
 285
 286         return arg;
 287 }