Implement line-history search (git log -L)
[git/git.git] / line-range.c
1 #include "git-compat-util.h"
2 #include "line-range.h"
3
4 /*
5 * Parse one item in the -L option
6 */
7 static const char *parse_loc(const char *spec, nth_line_fn_t nth_line,
8 void *data, long lines, long begin, long *ret)
9 {
10 char *term;
11 const char *line;
12 long num;
13 int reg_error;
14 regex_t regexp;
15 regmatch_t match[1];
16
17 /* Allow "-L <something>,+20" to mean starting at <something>
18 * for 20 lines, or "-L <something>,-5" for 5 lines ending at
19 * <something>.
20 */
21 if (1 < begin && (spec[0] == '+' || spec[0] == '-')) {
22 num = strtol(spec + 1, &term, 10);
23 if (term != spec + 1) {
24 if (!ret)
25 return term;
26 if (spec[0] == '-')
27 num = 0 - num;
28 if (0 < num)
29 *ret = begin + num - 2;
30 else if (!num)
31 *ret = begin;
32 else
33 *ret = begin + num;
34 return term;
35 }
36 return spec;
37 }
38 num = strtol(spec, &term, 10);
39 if (term != spec) {
40 if (ret)
41 *ret = num;
42 return term;
43 }
44 if (spec[0] != '/')
45 return spec;
46
47 /* it could be a regexp of form /.../ */
48 for (term = (char *) spec + 1; *term && *term != '/'; term++) {
49 if (*term == '\\')
50 term++;
51 }
52 if (*term != '/')
53 return spec;
54
55 /* in the scan-only case we are not interested in the regex */
56 if (!ret)
57 return term+1;
58
59 /* try [spec+1 .. term-1] as regexp */
60 *term = 0;
61 begin--; /* input is in human terms */
62 line = nth_line(data, begin);
63
64 if (!(reg_error = regcomp(&regexp, spec + 1, REG_NEWLINE)) &&
65 !(reg_error = regexec(&regexp, line, 1, match, 0))) {
66 const char *cp = line + match[0].rm_so;
67 const char *nline;
68
69 while (begin++ < lines) {
70 nline = nth_line(data, begin);
71 if (line <= cp && cp < nline)
72 break;
73 line = nline;
74 }
75 *ret = begin;
76 regfree(&regexp);
77 *term++ = '/';
78 return term;
79 }
80 else {
81 char errbuf[1024];
82 regerror(reg_error, &regexp, errbuf, 1024);
83 die("-L parameter '%s': %s", spec + 1, errbuf);
84 }
85 }
86
87 int parse_range_arg(const char *arg, nth_line_fn_t nth_line_cb,
88 void *cb_data, long lines, long *begin, long *end)
89 {
90 arg = parse_loc(arg, nth_line_cb, cb_data, lines, 1, begin);
91
92 if (*arg == ',')
93 arg = parse_loc(arg + 1, nth_line_cb, cb_data, lines, *begin + 1, end);
94
95 if (*arg)
96 return -1;
97
98 return 0;
99 }
100
101 const char *skip_range_arg(const char *arg)
102 {
103 arg = parse_loc(arg, NULL, NULL, 0, -1, NULL);
104
105 if (*arg == ',')
106 arg = parse_loc(arg+1, NULL, NULL, 0, 0, NULL);
107
108 return arg;
109 }