Add bug isolation howto, scraped from Linus.
[git/jnareb-git.git] / rev-parse.c
blob5a989825113b122d130448726c8eb97ffeb21ad1
1 /*
2 * rev-parse.c
4 * Copyright (C) Linus Torvalds, 2005
5 */
6 #include "cache.h"
7 #include "commit.h"
8 #include "refs.h"
9 #include "quote.h"
11 #define DO_REVS 1
12 #define DO_NOREV 2
13 #define DO_FLAGS 4
14 #define DO_NONFLAGS 8
15 static int filter = ~0;
17 static char *def = NULL;
19 #define NORMAL 0
20 #define REVERSED 1
21 static int show_type = NORMAL;
22 static int symbolic = 0;
23 static int output_sq = 0;
25 static int revs_count = 0;
28 * Some arguments are relevant "revision" arguments,
29 * others are about output format or other details.
30 * This sorts it all out.
32 static int is_rev_argument(const char *arg)
34 static const char *rev_args[] = {
35 "--all",
36 "--bisect",
37 "--dense",
38 "--header",
39 "--max-age=",
40 "--max-count=",
41 "--merge-order",
42 "--min-age=",
43 "--no-merges",
44 "--objects",
45 "--parents",
46 "--pretty",
47 "--show-breaks",
48 "--sparse",
49 "--topo-order",
50 "--unpacked",
51 NULL
53 const char **p = rev_args;
55 for (;;) {
56 const char *str = *p++;
57 int len;
58 if (!str)
59 return 0;
60 len = strlen(str);
61 if (!strcmp(arg, str) ||
62 (str[len-1] == '=' && !strncmp(arg, str, len)))
63 return 1;
67 /* Output argument as a string, either SQ or normal */
68 static void show(const char *arg)
70 if (output_sq) {
71 int sq = '\'', ch;
73 putchar(sq);
74 while ((ch = *arg++)) {
75 if (ch == sq)
76 fputs("'\\'", stdout);
77 putchar(ch);
79 putchar(sq);
80 putchar(' ');
82 else
83 puts(arg);
86 /* Output a revision, only if filter allows it */
87 static void show_rev(int type, const unsigned char *sha1, const char *name)
89 if (!(filter & DO_REVS))
90 return;
91 def = NULL;
92 revs_count++;
94 if (type != show_type)
95 putchar('^');
96 if (symbolic && name)
97 show(name);
98 else
99 show(sha1_to_hex(sha1));
102 /* Output a flag, only if filter allows it. */
103 static void show_flag(char *arg)
105 if (!(filter & DO_FLAGS))
106 return;
107 if (filter & (is_rev_argument(arg) ? DO_REVS : DO_NOREV))
108 show(arg);
111 static void show_default(void)
113 char *s = def;
115 if (s) {
116 unsigned char sha1[20];
118 def = NULL;
119 if (!get_sha1(s, sha1)) {
120 show_rev(NORMAL, sha1, s);
121 return;
126 static int show_reference(const char *refname, const unsigned char *sha1)
128 show_rev(NORMAL, sha1, refname);
129 return 0;
132 static void show_datestring(const char *flag, const char *datestr)
134 FILE *date;
135 static char buffer[100];
136 static char cmd[1000];
137 int len;
139 /* date handling requires both flags and revs */
140 if ((filter & (DO_FLAGS | DO_REVS)) != (DO_FLAGS | DO_REVS))
141 return;
142 len = strlen(flag);
143 memcpy(buffer, flag, len);
145 snprintf(cmd, sizeof(cmd), "date --date=%s +%%s", sq_quote(datestr));
146 date = popen(cmd, "r");
147 if (!date || !fgets(buffer + len, sizeof(buffer) - len, date))
148 die("git-rev-list: bad date string");
149 pclose(date);
150 len = strlen(buffer);
151 if (buffer[len-1] == '\n')
152 buffer[--len] = 0;
153 show(buffer);
156 static void show_file(const char *arg)
158 show_default();
159 if ((filter & (DO_NONFLAGS|DO_NOREV)) == (DO_NONFLAGS|DO_NOREV))
160 show(arg);
163 int main(int argc, char **argv)
165 int i, as_is = 0, verify = 0;
166 unsigned char sha1[20];
167 const char *prefix = setup_git_directory();
169 for (i = 1; i < argc; i++) {
170 char *arg = argv[i];
171 char *dotdot;
173 if (as_is) {
174 show_file(arg);
175 continue;
177 if (*arg == '-') {
178 if (!strcmp(arg, "--")) {
179 as_is = 1;
180 /* Pass on the "--" if we show anything but files.. */
181 if (filter & (DO_FLAGS | DO_REVS))
182 show_file(arg);
183 continue;
185 if (!strcmp(arg, "--default")) {
186 def = argv[i+1];
187 i++;
188 continue;
190 if (!strcmp(arg, "--revs-only")) {
191 filter &= ~DO_NOREV;
192 continue;
194 if (!strcmp(arg, "--no-revs")) {
195 filter &= ~DO_REVS;
196 continue;
198 if (!strcmp(arg, "--flags")) {
199 filter &= ~DO_NONFLAGS;
200 continue;
202 if (!strcmp(arg, "--no-flags")) {
203 filter &= ~DO_FLAGS;
204 continue;
206 if (!strcmp(arg, "--verify")) {
207 filter &= ~(DO_FLAGS|DO_NOREV);
208 verify = 1;
209 continue;
211 if (!strcmp(arg, "--sq")) {
212 output_sq = 1;
213 continue;
215 if (!strcmp(arg, "--not")) {
216 show_type ^= REVERSED;
217 continue;
219 if (!strcmp(arg, "--symbolic")) {
220 symbolic = 1;
221 continue;
223 if (!strcmp(arg, "--all")) {
224 for_each_ref(show_reference);
225 continue;
227 if (!strcmp(arg, "--show-prefix")) {
228 if (prefix)
229 puts(prefix);
230 continue;
232 if (!strcmp(arg, "--git-dir")) {
233 const char *gitdir = getenv(GIT_DIR_ENVIRONMENT);
234 static char cwd[PATH_MAX];
235 if (gitdir) {
236 puts(gitdir);
237 continue;
239 if (!prefix) {
240 puts(".git");
241 continue;
243 if (!getcwd(cwd, PATH_MAX))
244 die("unable to get current working directory");
245 printf("%s/.git\n", cwd);
246 continue;
248 if (!strncmp(arg, "--since=", 8)) {
249 show_datestring("--max-age=", arg+8);
250 continue;
252 if (!strncmp(arg, "--after=", 8)) {
253 show_datestring("--max-age=", arg+8);
254 continue;
256 if (!strncmp(arg, "--before=", 9)) {
257 show_datestring("--min-age=", arg+9);
258 continue;
260 if (!strncmp(arg, "--until=", 8)) {
261 show_datestring("--min-age=", arg+8);
262 continue;
264 if (verify)
265 die("Needed a single revision");
266 show_flag(arg);
267 continue;
270 /* Not a flag argument */
271 dotdot = strstr(arg, "..");
272 if (dotdot) {
273 unsigned char end[20];
274 char *n = dotdot+2;
275 *dotdot = 0;
276 if (!get_sha1(arg, sha1)) {
277 if (!*n)
278 n = "HEAD";
279 if (!get_sha1(n, end)) {
280 show_rev(NORMAL, end, n);
281 show_rev(REVERSED, sha1, arg);
282 continue;
285 *dotdot = '.';
287 if (!get_sha1(arg, sha1)) {
288 show_rev(NORMAL, sha1, arg);
289 continue;
291 if (*arg == '^' && !get_sha1(arg+1, sha1)) {
292 show_rev(REVERSED, sha1, arg+1);
293 continue;
295 if (verify)
296 die("Needed a single revision");
297 as_is = 1;
298 show_file(arg);
300 show_default();
301 if (verify && revs_count != 1)
302 die("Needed a single revision");
303 return 0;