git-push: add documentation for the newly added --mirror mode
[git/git.git] / builtin-reset.c
1 /*
2 * "git reset" builtin command
3 *
4 * Copyright (c) 2007 Carlos Rica
5 *
6 * Based on git-reset.sh, which is
7 *
8 * Copyright (c) 2005, 2006 Linus Torvalds and Junio C Hamano
9 */
10 #include "cache.h"
11 #include "tag.h"
12 #include "object.h"
13 #include "commit.h"
14 #include "run-command.h"
15 #include "refs.h"
16 #include "diff.h"
17 #include "diffcore.h"
18 #include "tree.h"
19
20 static const char builtin_reset_usage[] =
21 "git-reset [--mixed | --soft | --hard] [-q] [<commit-ish>] [ [--] <paths>...]";
22
23 static char *args_to_str(const char **argv)
24 {
25 char *buf = NULL;
26 unsigned long len, space = 0, nr = 0;
27
28 for (; *argv; argv++) {
29 len = strlen(*argv);
30 ALLOC_GROW(buf, nr + 1 + len, space);
31 if (nr)
32 buf[nr++] = ' ';
33 memcpy(buf + nr, *argv, len);
34 nr += len;
35 }
36 ALLOC_GROW(buf, nr + 1, space);
37 buf[nr] = '\0';
38
39 return buf;
40 }
41
42 static inline int is_merge(void)
43 {
44 return !access(git_path("MERGE_HEAD"), F_OK);
45 }
46
47 static int unmerged_files(void)
48 {
49 char b;
50 ssize_t len;
51 struct child_process cmd;
52 const char *argv_ls_files[] = {"ls-files", "--unmerged", NULL};
53
54 memset(&cmd, 0, sizeof(cmd));
55 cmd.argv = argv_ls_files;
56 cmd.git_cmd = 1;
57 cmd.out = -1;
58
59 if (start_command(&cmd))
60 die("Could not run sub-command: git ls-files");
61
62 len = xread(cmd.out, &b, 1);
63 if (len < 0)
64 die("Could not read output from git ls-files: %s",
65 strerror(errno));
66 finish_command(&cmd);
67
68 return len;
69 }
70
71 static int reset_index_file(const unsigned char *sha1, int is_hard_reset)
72 {
73 int i = 0;
74 const char *args[6];
75
76 args[i++] = "read-tree";
77 args[i++] = "-v";
78 args[i++] = "--reset";
79 if (is_hard_reset)
80 args[i++] = "-u";
81 args[i++] = sha1_to_hex(sha1);
82 args[i] = NULL;
83
84 return run_command_v_opt(args, RUN_GIT_CMD);
85 }
86
87 static void print_new_head_line(struct commit *commit)
88 {
89 const char *hex, *dots = "...", *body;
90
91 hex = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
92 if (!hex) {
93 hex = sha1_to_hex(commit->object.sha1);
94 dots = "";
95 }
96 printf("HEAD is now at %s%s", hex, dots);
97 body = strstr(commit->buffer, "\n\n");
98 if (body) {
99 const char *eol;
100 size_t len;
101 body += 2;
102 eol = strchr(body, '\n');
103 len = eol ? eol - body : strlen(body);
104 printf(" %.*s\n", (int) len, body);
105 }
106 else
107 printf("\n");
108 }
109
110 static int update_index_refresh(void)
111 {
112 const char *argv_update_index[] = {"update-index", "--refresh", NULL};
113 return run_command_v_opt(argv_update_index, RUN_GIT_CMD);
114 }
115
116 struct update_cb_data {
117 int index_fd;
118 struct lock_file *lock;
119 int exit_code;
120 };
121
122 static void update_index_from_diff(struct diff_queue_struct *q,
123 struct diff_options *opt, void *data)
124 {
125 int i;
126 struct update_cb_data *cb = data;
127
128 /* do_diff_cache() mangled the index */
129 discard_cache();
130 read_cache();
131
132 for (i = 0; i < q->nr; i++) {
133 struct diff_filespec *one = q->queue[i]->one;
134 if (one->mode) {
135 struct cache_entry *ce;
136 ce = make_cache_entry(one->mode, one->sha1, one->path,
137 0, 0);
138 add_cache_entry(ce, ADD_CACHE_OK_TO_ADD |
139 ADD_CACHE_OK_TO_REPLACE);
140 } else
141 remove_file_from_cache(one->path);
142 }
143
144 cb->exit_code = write_cache(cb->index_fd, active_cache, active_nr) ||
145 close(cb->index_fd) ||
146 commit_locked_index(cb->lock);
147 }
148
149 static int read_from_tree(const char *prefix, const char **argv,
150 unsigned char *tree_sha1)
151 {
152 struct diff_options opt;
153 struct update_cb_data cb;
154
155 memset(&opt, 0, sizeof(opt));
156 diff_tree_setup_paths(get_pathspec(prefix, (const char **)argv), &opt);
157 opt.output_format = DIFF_FORMAT_CALLBACK;
158 opt.format_callback = update_index_from_diff;
159 opt.format_callback_data = &cb;
160
161 cb.lock = xcalloc(1, sizeof(struct lock_file));
162 cb.index_fd = hold_locked_index(cb.lock, 1);
163 cb.exit_code = 0;
164 read_cache();
165 if (do_diff_cache(tree_sha1, &opt))
166 return 1;
167 diffcore_std(&opt);
168 diff_flush(&opt);
169
170 return cb.exit_code;
171 }
172
173 static void prepend_reflog_action(const char *action, char *buf, size_t size)
174 {
175 const char *sep = ": ";
176 const char *rla = getenv("GIT_REFLOG_ACTION");
177 if (!rla)
178 rla = sep = "";
179 if (snprintf(buf, size, "%s%s%s", rla, sep, action) >= size)
180 warning("Reflog action message too long: %.*s...", 50, buf);
181 }
182
183 enum reset_type { MIXED, SOFT, HARD, NONE };
184 static const char *reset_type_names[] = { "mixed", "soft", "hard", NULL };
185
186 int cmd_reset(int argc, const char **argv, const char *prefix)
187 {
188 int i = 1, reset_type = NONE, update_ref_status = 0, quiet = 0;
189 const char *rev = "HEAD";
190 unsigned char sha1[20], *orig = NULL, sha1_orig[20],
191 *old_orig = NULL, sha1_old_orig[20];
192 struct commit *commit;
193 char *reflog_action, msg[1024];
194
195 git_config(git_default_config);
196
197 reflog_action = args_to_str(argv);
198 setenv("GIT_REFLOG_ACTION", reflog_action, 0);
199
200 while (i < argc) {
201 if (!strcmp(argv[i], "--mixed")) {
202 reset_type = MIXED;
203 i++;
204 }
205 else if (!strcmp(argv[i], "--soft")) {
206 reset_type = SOFT;
207 i++;
208 }
209 else if (!strcmp(argv[i], "--hard")) {
210 reset_type = HARD;
211 i++;
212 }
213 else if (!strcmp(argv[i], "-q")) {
214 quiet = 1;
215 i++;
216 }
217 else
218 break;
219 }
220
221 if (i < argc && argv[i][0] != '-')
222 rev = argv[i++];
223
224 if (get_sha1(rev, sha1))
225 die("Failed to resolve '%s' as a valid ref.", rev);
226
227 commit = lookup_commit_reference(sha1);
228 if (!commit)
229 die("Could not parse object '%s'.", rev);
230 hashcpy(sha1, commit->object.sha1);
231
232 if (i < argc && !strcmp(argv[i], "--"))
233 i++;
234 else if (i < argc && argv[i][0] == '-')
235 usage(builtin_reset_usage);
236
237 /* git reset tree [--] paths... can be used to
238 * load chosen paths from the tree into the index without
239 * affecting the working tree nor HEAD. */
240 if (i < argc) {
241 if (reset_type == MIXED)
242 warning("--mixed option is deprecated with paths.");
243 else if (reset_type != NONE)
244 die("Cannot do %s reset with paths.",
245 reset_type_names[reset_type]);
246 if (read_from_tree(prefix, argv + i, sha1))
247 return 1;
248 return update_index_refresh() ? 1 : 0;
249 }
250 if (reset_type == NONE)
251 reset_type = MIXED; /* by default */
252
253 /* Soft reset does not touch the index file nor the working tree
254 * at all, but requires them in a good order. Other resets reset
255 * the index file to the tree object we are switching to. */
256 if (reset_type == SOFT) {
257 if (is_merge() || unmerged_files())
258 die("Cannot do a soft reset in the middle of a merge.");
259 }
260 else if (reset_index_file(sha1, (reset_type == HARD)))
261 die("Could not reset index file to revision '%s'.", rev);
262
263 /* Any resets update HEAD to the head being switched to,
264 * saving the previous head in ORIG_HEAD before. */
265 if (!get_sha1("ORIG_HEAD", sha1_old_orig))
266 old_orig = sha1_old_orig;
267 if (!get_sha1("HEAD", sha1_orig)) {
268 orig = sha1_orig;
269 prepend_reflog_action("updating ORIG_HEAD", msg, sizeof(msg));
270 update_ref(msg, "ORIG_HEAD", orig, old_orig, 0, MSG_ON_ERR);
271 }
272 else if (old_orig)
273 delete_ref("ORIG_HEAD", old_orig);
274 prepend_reflog_action("updating HEAD", msg, sizeof(msg));
275 update_ref_status = update_ref(msg, "HEAD", sha1, orig, 0, MSG_ON_ERR);
276
277 switch (reset_type) {
278 case HARD:
279 if (!update_ref_status && !quiet)
280 print_new_head_line(commit);
281 break;
282 case SOFT: /* Nothing else to do. */
283 break;
284 case MIXED: /* Report what has not been updated. */
285 update_index_refresh();
286 break;
287 }
288
289 unlink(git_path("MERGE_HEAD"));
290 unlink(git_path("rr-cache/MERGE_RR"));
291 unlink(git_path("MERGE_MSG"));
292 unlink(git_path("SQUASH_MSG"));
293
294 free(reflog_action);
295
296 return update_ref_status;
297 }