mergetool: support --tool-help option like difftool does
[git] / entry.c
1 #include "cache.h"
2 #include "blob.h"
3 #include "dir.h"
4 #include "streaming.h"
5
6 static void create_directories(const char *path, int path_len,
7                                const struct checkout *state)
8 {
9         char *buf = xmalloc(path_len + 1);
10         int len = 0;
11
12         while (len < path_len) {
13                 do {
14                         buf[len] = path[len];
15                         len++;
16                 } while (len < path_len && path[len] != '/');
17                 if (len >= path_len)
18                         break;
19                 buf[len] = 0;
20
21                 /*
22                  * For 'checkout-index --prefix=<dir>', <dir> is
23                  * allowed to be a symlink to an existing directory,
24                  * and we set 'state->base_dir_len' below, such that
25                  * we test the path components of the prefix with the
26                  * stat() function instead of the lstat() function.
27                  */
28                 if (has_dirs_only_path(buf, len, state->base_dir_len))
29                         continue; /* ok, it is already a directory. */
30
31                 /*
32                  * If this mkdir() would fail, it could be that there
33                  * is already a symlink or something else exists
34                  * there, therefore we then try to unlink it and try
35                  * one more time to create the directory.
36                  */
37                 if (mkdir(buf, 0777)) {
38                         if (errno == EEXIST && state->force &&
39                             !unlink_or_warn(buf) && !mkdir(buf, 0777))
40                                 continue;
41                         die_errno("cannot create directory at '%s'", buf);
42                 }
43         }
44         free(buf);
45 }
46
47 static void remove_subtree(const char *path)
48 {
49         DIR *dir = opendir(path);
50         struct dirent *de;
51         char pathbuf[PATH_MAX];
52         char *name;
53
54         if (!dir)
55                 die_errno("cannot opendir '%s'", path);
56         strcpy(pathbuf, path);
57         name = pathbuf + strlen(path);
58         *name++ = '/';
59         while ((de = readdir(dir)) != NULL) {
60                 struct stat st;
61                 if (is_dot_or_dotdot(de->d_name))
62                         continue;
63                 strcpy(name, de->d_name);
64                 if (lstat(pathbuf, &st))
65                         die_errno("cannot lstat '%s'", pathbuf);
66                 if (S_ISDIR(st.st_mode))
67                         remove_subtree(pathbuf);
68                 else if (unlink(pathbuf))
69                         die_errno("cannot unlink '%s'", pathbuf);
70         }
71         closedir(dir);
72         if (rmdir(path))
73                 die_errno("cannot rmdir '%s'", path);
74 }
75
76 static int create_file(const char *path, unsigned int mode)
77 {
78         mode = (mode & 0100) ? 0777 : 0666;
79         return open(path, O_WRONLY | O_CREAT | O_EXCL, mode);
80 }
81
82 static void *read_blob_entry(struct cache_entry *ce, unsigned long *size)
83 {
84         enum object_type type;
85         void *new = read_sha1_file(ce->sha1, &type, size);
86
87         if (new) {
88                 if (type == OBJ_BLOB)
89                         return new;
90                 free(new);
91         }
92         return NULL;
93 }
94
95 static int open_output_fd(char *path, struct cache_entry *ce, int to_tempfile)
96 {
97         int symlink = (ce->ce_mode & S_IFMT) != S_IFREG;
98         if (to_tempfile) {
99                 strcpy(path, symlink
100                        ? ".merge_link_XXXXXX" : ".merge_file_XXXXXX");
101                 return mkstemp(path);
102         } else {
103                 return create_file(path, !symlink ? ce->ce_mode : 0666);
104         }
105 }
106
107 static int fstat_output(int fd, const struct checkout *state, struct stat *st)
108 {
109         /* use fstat() only when path == ce->name */
110         if (fstat_is_reliable() &&
111             state->refresh_cache && !state->base_dir_len) {
112                 fstat(fd, st);
113                 return 1;
114         }
115         return 0;
116 }
117
118 static int streaming_write_entry(struct cache_entry *ce, char *path,
119                                  struct stream_filter *filter,
120                                  const struct checkout *state, int to_tempfile,
121                                  int *fstat_done, struct stat *statbuf)
122 {
123         int result = -1;
124         int fd;
125
126         fd = open_output_fd(path, ce, to_tempfile);
127         if (0 <= fd) {
128                 result = stream_blob_to_fd(fd, ce->sha1, filter, 1);
129                 *fstat_done = fstat_output(fd, state, statbuf);
130                 result = close(fd);
131         }
132         if (result && 0 <= fd)
133                 unlink(path);
134         return result;
135 }
136
137 static int write_entry(struct cache_entry *ce, char *path, const struct checkout *state, int to_tempfile)
138 {
139         unsigned int ce_mode_s_ifmt = ce->ce_mode & S_IFMT;
140         int fd, ret, fstat_done = 0;
141         char *new;
142         struct strbuf buf = STRBUF_INIT;
143         unsigned long size;
144         size_t wrote, newsize = 0;
145         struct stat st;
146
147         if (ce_mode_s_ifmt == S_IFREG) {
148                 struct stream_filter *filter = get_stream_filter(path, ce->sha1);
149                 if (filter &&
150                     !streaming_write_entry(ce, path, filter,
151                                            state, to_tempfile,
152                                            &fstat_done, &st))
153                         goto finish;
154         }
155
156         switch (ce_mode_s_ifmt) {
157         case S_IFREG:
158         case S_IFLNK:
159                 new = read_blob_entry(ce, &size);
160                 if (!new)
161                         return error("unable to read sha1 file of %s (%s)",
162                                 path, sha1_to_hex(ce->sha1));
163
164                 if (ce_mode_s_ifmt == S_IFLNK && has_symlinks && !to_tempfile) {
165                         ret = symlink(new, path);
166                         free(new);
167                         if (ret)
168                                 return error("unable to create symlink %s (%s)",
169                                              path, strerror(errno));
170                         break;
171                 }
172
173                 /*
174                  * Convert from git internal format to working tree format
175                  */
176                 if (ce_mode_s_ifmt == S_IFREG &&
177                     convert_to_working_tree(ce->name, new, size, &buf)) {
178                         free(new);
179                         new = strbuf_detach(&buf, &newsize);
180                         size = newsize;
181                 }
182
183                 fd = open_output_fd(path, ce, to_tempfile);
184                 if (fd < 0) {
185                         free(new);
186                         return error("unable to create file %s (%s)",
187                                 path, strerror(errno));
188                 }
189
190                 wrote = write_in_full(fd, new, size);
191                 if (!to_tempfile)
192                         fstat_done = fstat_output(fd, state, &st);
193                 close(fd);
194                 free(new);
195                 if (wrote != size)
196                         return error("unable to write file %s", path);
197                 break;
198         case S_IFGITLINK:
199                 if (to_tempfile)
200                         return error("cannot create temporary subproject %s", path);
201                 if (mkdir(path, 0777) < 0)
202                         return error("cannot create subproject directory %s", path);
203                 break;
204         default:
205                 return error("unknown file mode for %s in index", path);
206         }
207
208 finish:
209         if (state->refresh_cache) {
210                 if (!fstat_done)
211                         lstat(ce->name, &st);
212                 fill_stat_cache_info(ce, &st);
213         }
214         return 0;
215 }
216
217 /*
218  * This is like 'lstat()', except it refuses to follow symlinks
219  * in the path, after skipping "skiplen".
220  */
221 static int check_path(const char *path, int len, struct stat *st, int skiplen)
222 {
223         const char *slash = path + len;
224
225         while (path < slash && *slash != '/')
226                 slash--;
227         if (!has_dirs_only_path(path, slash - path, skiplen)) {
228                 errno = ENOENT;
229                 return -1;
230         }
231         return lstat(path, st);
232 }
233
234 int checkout_entry(struct cache_entry *ce, const struct checkout *state, char *topath)
235 {
236         static char path[PATH_MAX + 1];
237         struct stat st;
238         int len = state->base_dir_len;
239
240         if (topath)
241                 return write_entry(ce, topath, state, 1);
242
243         memcpy(path, state->base_dir, len);
244         strcpy(path + len, ce->name);
245         len += ce_namelen(ce);
246
247         if (!check_path(path, len, &st, state->base_dir_len)) {
248                 unsigned changed = ce_match_stat(ce, &st, CE_MATCH_IGNORE_VALID|CE_MATCH_IGNORE_SKIP_WORKTREE);
249                 if (!changed)
250                         return 0;
251                 if (!state->force) {
252                         if (!state->quiet)
253                                 fprintf(stderr, "%s already exists, no checkout\n", path);
254                         return -1;
255                 }
256
257                 /*
258                  * We unlink the old file, to get the new one with the
259                  * right permissions (including umask, which is nasty
260                  * to emulate by hand - much easier to let the system
261                  * just do the right thing)
262                  */
263                 if (S_ISDIR(st.st_mode)) {
264                         /* If it is a gitlink, leave it alone! */
265                         if (S_ISGITLINK(ce->ce_mode))
266                                 return 0;
267                         if (!state->force)
268                                 return error("%s is a directory", path);
269                         remove_subtree(path);
270                 } else if (unlink(path))
271                         return error("unable to unlink old '%s' (%s)", path, strerror(errno));
272         } else if (state->not_new)
273                 return 0;
274         create_directories(path, len, state);
275         return write_entry(ce, path, state, 0);
276 }