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 > 0 ? begin + num : 1;
  51                         return term;
  52                 }
  53                 return spec;
  54         }
  55         num = strtol(spec, &term, 10);
  56         if (term != spec) {
  57                 if (ret) {
  58                         if (num <= 0)
  59                                 die("-L invalid line number: %ld", num);
  60                         *ret = num;
  61                 }
  62                 return term;
  63         }
  64
  65         if (begin < 0) {
  66                 if (spec[0] != '^')
  67                         begin = -begin;
  68                 else {
  69                         begin = 1;
  70                         spec++;
  71                 }
  72         }
  73
  74         if (spec[0] != '/')
  75                 return spec;
  76
  77         /* it could be a regexp of form /.../ */
  78         for (term = (char *) spec + 1; *term && *term != '/'; term++) {
  79                 if (*term == '\\')
  80                         term++;
  81         }
  82         if (*term != '/')
  83                 return spec;
  84
  85         /* in the scan-only case we are not interested in the regex */
  86         if (!ret)
  87                 return term+1;
  88
  89         /* try [spec+1 .. term-1] as regexp */
  90         *term = 0;
  91         begin--; /* input is in human terms */
  92         line = nth_line(data, begin);
  93
  94         if (!(reg_error = regcomp(&regexp, spec + 1, REG_NEWLINE)) &&
  95             !(reg_error = regexec(&regexp, line, 1, match, 0))) {
  96                 const char *cp = line + match[0].rm_so;
  97                 const char *nline;
  98
  99                 while (begin++ < lines) {
 100                         nline = nth_line(data, begin);
 101                         if (line <= cp && cp < nline)
 102                                 break;
 103                         line = nline;
 104                 }
 105                 *ret = begin;
 106                 regfree(&regexp);
 107                 *term++ = '/';
 108                 return term;
 109         }
 110         else {
 111                 char errbuf[1024];
 112                 regerror(reg_error, &regexp, errbuf, 1024);
 113                 die("-L parameter '%s' starting at line %ld: %s",
 114                     spec + 1, begin + 1, errbuf);
 115         }
 116 }
 117
 118 static int match_funcname(xdemitconf_t *xecfg, const char *bol, const char *eol)
 119 {
 120         if (xecfg) {
 121                 char buf[1];
 122                 return xecfg->find_func(bol, eol - bol, buf, 1,
 123                                         xecfg->find_func_priv) >= 0;
 124         }
 125
 126         if (bol == eol)
 127                 return 0;
 128         if (isalpha(*bol) || *bol == '_' || *bol == '$')
 129                 return 1;
 130         return 0;
 131 }
 132
 133 static const char *find_funcname_matching_regexp(xdemitconf_t *xecfg, const char *start,
 134                                                  regex_t *regexp)
 135 {
 136         int reg_error;
 137         regmatch_t match[1];
 138         while (1) {
 139                 const char *bol, *eol;
 140                 reg_error = regexec(regexp, start, 1, match, 0);
 141                 if (reg_error == REG_NOMATCH)
 142                         return NULL;
 143                 else if (reg_error) {
 144                         char errbuf[1024];
 145                         regerror(reg_error, regexp, errbuf, 1024);
 146                         die("-L parameter: regexec() failed: %s", errbuf);
 147                 }
 148                 /* determine extent of line matched */
 149                 bol = start+match[0].rm_so;
 150                 eol = start+match[0].rm_eo;
 151                 while (bol > start && *bol != '\n')
 152                         bol--;
 153                 if (*bol == '\n')
 154                         bol++;
 155                 while (*eol && *eol != '\n')
 156                         eol++;
 157                 if (*eol == '\n')
 158                         eol++;
 159                 /* is it a funcname line? */
 160                 if (match_funcname(xecfg, (char*) bol, (char*) eol))
 161                         return bol;
 162                 start = eol;
 163         }
 164 }
 165
 166 static const char *parse_range_funcname(const char *arg, nth_line_fn_t nth_line_cb,
 167                                         void *cb_data, long lines, long anchor, long *begin, long *end,
 168                                         const char *path)
 169 {
 170         char *pattern;
 171         const char *term;
 172         struct userdiff_driver *drv;
 173         xdemitconf_t *xecfg = NULL;
 174         const char *start;
 175         const char *p;
 176         int reg_error;
 177         regex_t regexp;
 178
 179         if (*arg == '^') {
 180                 anchor = 1;
 181                 arg++;
 182         }
 183
 184         assert(*arg == ':');
 185         term = arg+1;
 186         while (*term && *term != ':') {
 187                 if (*term == '\\' && *(term+1))
 188                         term++;
 189                 term++;
 190         }
 191         if (term == arg+1)
 192                 return NULL;
 193         if (!begin) /* skip_range_arg case */
 194                 return term;
 195
 196         pattern = xstrndup(arg+1, term-(arg+1));
 197
 198         anchor--; /* input is in human terms */
 199         start = nth_line_cb(cb_data, anchor);
 200
 201         drv = userdiff_find_by_path(path);
 202         if (drv && drv->funcname.pattern) {
 203                 const struct userdiff_funcname *pe = &drv->funcname;
 204                 xecfg = xcalloc(1, sizeof(*xecfg));
 205                 xdiff_set_find_func(xecfg, pe->pattern, pe->cflags);
 206         }
 207
 208         reg_error = regcomp(&regexp, pattern, REG_NEWLINE);
 209         if (reg_error) {
 210                 char errbuf[1024];
 211                 regerror(reg_error, &regexp, errbuf, 1024);
 212                 die("-L parameter '%s': %s", pattern, errbuf);
 213         }
 214
 215         p = find_funcname_matching_regexp(xecfg, (char*) start, &regexp);
 216         if (!p)
 217                 die("-L parameter '%s' starting at line %ld: no match",
 218                     pattern, anchor + 1);
 219         *begin = 0;
 220         while (p > nth_line_cb(cb_data, *begin))
 221                 (*begin)++;
 222
 223         if (*begin >= lines)
 224                 die("-L parameter '%s' matches at EOF", pattern);
 225
 226         *end = *begin+1;
 227         while (*end < lines) {
 228                 const char *bol = nth_line_cb(cb_data, *end);
 229                 const char *eol = nth_line_cb(cb_data, *end+1);
 230                 if (match_funcname(xecfg, bol, eol))
 231                         break;
 232                 (*end)++;
 233         }
 234
 235         regfree(&regexp);
 236         free(xecfg);
 237         free(pattern);
 238
 239         /* compensate for 1-based numbering */
 240         (*begin)++;
 241
 242         return term;
 243 }
 244
 245 int parse_range_arg(const char *arg, nth_line_fn_t nth_line_cb,
 246                     void *cb_data, long lines, long anchor,
 247                     long *begin, long *end, const char *path)
 248 {
 249         *begin = *end = 0;
 250
 251         if (anchor < 1)
 252                 anchor = 1;
 253         if (anchor > lines)
 254                 anchor = lines + 1;
 255
 256         if (*arg == ':' || (*arg == '^' && *(arg + 1) == ':')) {
 257                 arg = parse_range_funcname(arg, nth_line_cb, cb_data, lines, anchor, begin, end, path);
 258                 if (!arg || *arg)
 259                         return -1;
 260                 return 0;
 261         }
 262
 263         arg = parse_loc(arg, nth_line_cb, cb_data, lines, -anchor, begin);
 264
 265         if (*arg == ',')
 266                 arg = parse_loc(arg + 1, nth_line_cb, cb_data, lines, *begin + 1, end);
 267
 268         if (*arg)
 269                 return -1;
 270
 271         if (*begin && *end && *end < *begin) {
 272                 SWAP(*end, *begin);
 273         }
 274
 275         return 0;
 276 }
 277
 278 const char *skip_range_arg(const char *arg)
 279 {
 280         if (*arg == ':' || (*arg == '^' && *(arg + 1) == ':'))
 281                 return parse_range_funcname(arg, NULL, NULL, 0, 0, NULL, NULL, NULL);
 282
 283         arg = parse_loc(arg, NULL, NULL, 0, -1, NULL);
 284
 285         if (*arg == ',')
 286                 arg = parse_loc(arg+1, NULL, NULL, 0, 0, NULL);
 287
 288         return arg;
 289 }