http-walker: reduce O(n) ops with doubly-linked list
[git] / worktree.c
1 #include "cache.h"
2 #include "refs.h"
3 #include "strbuf.h"
4 #include "worktree.h"
5 #include "dir.h"
6 #include "wt-status.h"
7
8 void free_worktrees(struct worktree **worktrees)
9 {
10         int i = 0;
11
12         for (i = 0; worktrees[i]; i++) {
13                 free(worktrees[i]->path);
14                 free(worktrees[i]->id);
15                 free(worktrees[i]->head_ref);
16                 free(worktrees[i]);
17         }
18         free (worktrees);
19 }
20
21 /*
22  * read 'path_to_ref' into 'ref'.  Also if is_detached is not NULL,
23  * set is_detached to 1 (0) if the ref is detached (is not detached).
24  *
25  * $GIT_COMMON_DIR/$symref (e.g. HEAD) is practically outside $GIT_DIR so
26  * for linked worktrees, `resolve_ref_unsafe()` won't work (it uses
27  * git_path). Parse the ref ourselves.
28  *
29  * return -1 if the ref is not a proper ref, 0 otherwise (success)
30  */
31 static int parse_ref(char *path_to_ref, struct strbuf *ref, int *is_detached)
32 {
33         if (is_detached)
34                 *is_detached = 0;
35         if (!strbuf_readlink(ref, path_to_ref, 0)) {
36                 /* HEAD is symbolic link */
37                 if (!starts_with(ref->buf, "refs/") ||
38                                 check_refname_format(ref->buf, 0))
39                         return -1;
40         } else if (strbuf_read_file(ref, path_to_ref, 0) >= 0) {
41                 /* textual symref or detached */
42                 if (!starts_with(ref->buf, "ref:")) {
43                         if (is_detached)
44                                 *is_detached = 1;
45                 } else {
46                         strbuf_remove(ref, 0, strlen("ref:"));
47                         strbuf_trim(ref);
48                         if (check_refname_format(ref->buf, 0))
49                                 return -1;
50                 }
51         } else
52                 return -1;
53         return 0;
54 }
55
56 /**
57  * Add the head_sha1 and head_ref (if not detached) to the given worktree
58  */
59 static void add_head_info(struct strbuf *head_ref, struct worktree *worktree)
60 {
61         if (head_ref->len) {
62                 if (worktree->is_detached) {
63                         get_sha1_hex(head_ref->buf, worktree->head_sha1);
64                 } else {
65                         resolve_ref_unsafe(head_ref->buf, 0, worktree->head_sha1, NULL);
66                         worktree->head_ref = strbuf_detach(head_ref, NULL);
67                 }
68         }
69 }
70
71 /**
72  * get the main worktree
73  */
74 static struct worktree *get_main_worktree(void)
75 {
76         struct worktree *worktree = NULL;
77         struct strbuf path = STRBUF_INIT;
78         struct strbuf worktree_path = STRBUF_INIT;
79         struct strbuf head_ref = STRBUF_INIT;
80         int is_bare = 0;
81         int is_detached = 0;
82
83         strbuf_addstr(&worktree_path, absolute_path(get_git_common_dir()));
84         is_bare = !strbuf_strip_suffix(&worktree_path, "/.git");
85         if (is_bare)
86                 strbuf_strip_suffix(&worktree_path, "/.");
87
88         strbuf_addf(&path, "%s/HEAD", get_git_common_dir());
89
90         if (parse_ref(path.buf, &head_ref, &is_detached) < 0)
91                 goto done;
92
93         worktree = xmalloc(sizeof(struct worktree));
94         worktree->path = strbuf_detach(&worktree_path, NULL);
95         worktree->id = NULL;
96         worktree->is_bare = is_bare;
97         worktree->head_ref = NULL;
98         worktree->is_detached = is_detached;
99         worktree->is_current = 0;
100         add_head_info(&head_ref, worktree);
101
102 done:
103         strbuf_release(&path);
104         strbuf_release(&worktree_path);
105         strbuf_release(&head_ref);
106         return worktree;
107 }
108
109 static struct worktree *get_linked_worktree(const char *id)
110 {
111         struct worktree *worktree = NULL;
112         struct strbuf path = STRBUF_INIT;
113         struct strbuf worktree_path = STRBUF_INIT;
114         struct strbuf head_ref = STRBUF_INIT;
115         int is_detached = 0;
116
117         if (!id)
118                 die("Missing linked worktree name");
119
120         strbuf_git_common_path(&path, "worktrees/%s/gitdir", id);
121         if (strbuf_read_file(&worktree_path, path.buf, 0) <= 0)
122                 /* invalid gitdir file */
123                 goto done;
124
125         strbuf_rtrim(&worktree_path);
126         if (!strbuf_strip_suffix(&worktree_path, "/.git")) {
127                 strbuf_reset(&worktree_path);
128                 strbuf_addstr(&worktree_path, absolute_path("."));
129                 strbuf_strip_suffix(&worktree_path, "/.");
130         }
131
132         strbuf_reset(&path);
133         strbuf_addf(&path, "%s/worktrees/%s/HEAD", get_git_common_dir(), id);
134
135         if (parse_ref(path.buf, &head_ref, &is_detached) < 0)
136                 goto done;
137
138         worktree = xmalloc(sizeof(struct worktree));
139         worktree->path = strbuf_detach(&worktree_path, NULL);
140         worktree->id = xstrdup(id);
141         worktree->is_bare = 0;
142         worktree->head_ref = NULL;
143         worktree->is_detached = is_detached;
144         worktree->is_current = 0;
145         add_head_info(&head_ref, worktree);
146
147 done:
148         strbuf_release(&path);
149         strbuf_release(&worktree_path);
150         strbuf_release(&head_ref);
151         return worktree;
152 }
153
154 static void mark_current_worktree(struct worktree **worktrees)
155 {
156         struct strbuf git_dir = STRBUF_INIT;
157         struct strbuf path = STRBUF_INIT;
158         int i;
159
160         strbuf_addstr(&git_dir, absolute_path(get_git_dir()));
161         for (i = 0; worktrees[i]; i++) {
162                 struct worktree *wt = worktrees[i];
163                 strbuf_addstr(&path, absolute_path(get_worktree_git_dir(wt)));
164                 wt->is_current = !fspathcmp(git_dir.buf, path.buf);
165                 strbuf_reset(&path);
166                 if (wt->is_current)
167                         break;
168         }
169         strbuf_release(&git_dir);
170         strbuf_release(&path);
171 }
172
173 struct worktree **get_worktrees(void)
174 {
175         struct worktree **list = NULL;
176         struct strbuf path = STRBUF_INIT;
177         DIR *dir;
178         struct dirent *d;
179         int counter = 0, alloc = 2;
180
181         list = xmalloc(alloc * sizeof(struct worktree *));
182
183         if ((list[counter] = get_main_worktree()))
184                 counter++;
185
186         strbuf_addf(&path, "%s/worktrees", get_git_common_dir());
187         dir = opendir(path.buf);
188         strbuf_release(&path);
189         if (dir) {
190                 while ((d = readdir(dir)) != NULL) {
191                         struct worktree *linked = NULL;
192                         if (!strcmp(d->d_name, ".") || !strcmp(d->d_name, ".."))
193                                 continue;
194
195                         if ((linked = get_linked_worktree(d->d_name))) {
196                                 ALLOC_GROW(list, counter + 1, alloc);
197                                 list[counter++] = linked;
198                         }
199                 }
200                 closedir(dir);
201         }
202         ALLOC_GROW(list, counter + 1, alloc);
203         list[counter] = NULL;
204
205         mark_current_worktree(list);
206         return list;
207 }
208
209 const char *get_worktree_git_dir(const struct worktree *wt)
210 {
211         if (!wt)
212                 return get_git_dir();
213         else if (!wt->id)
214                 return get_git_common_dir();
215         else
216                 return git_common_path("worktrees/%s", wt->id);
217 }
218
219 int is_worktree_being_rebased(const struct worktree *wt,
220                               const char *target)
221 {
222         struct wt_status_state state;
223         int found_rebase;
224
225         memset(&state, 0, sizeof(state));
226         found_rebase = wt_status_check_rebase(wt, &state) &&
227                 ((state.rebase_in_progress ||
228                   state.rebase_interactive_in_progress) &&
229                  state.branch &&
230                  starts_with(target, "refs/heads/") &&
231                  !strcmp(state.branch, target + strlen("refs/heads/")));
232         free(state.branch);
233         free(state.onto);
234         return found_rebase;
235 }
236
237 int is_worktree_being_bisected(const struct worktree *wt,
238                                const char *target)
239 {
240         struct wt_status_state state;
241         int found_rebase;
242
243         memset(&state, 0, sizeof(state));
244         found_rebase = wt_status_check_bisect(wt, &state) &&
245                 state.branch &&
246                 starts_with(target, "refs/heads/") &&
247                 !strcmp(state.branch, target + strlen("refs/heads/"));
248         free(state.branch);
249         return found_rebase;
250 }
251
252 /*
253  * note: this function should be able to detect shared symref even if
254  * HEAD is temporarily detached (e.g. in the middle of rebase or
255  * bisect). New commands that do similar things should update this
256  * function as well.
257  */
258 const struct worktree *find_shared_symref(const char *symref,
259                                           const char *target)
260 {
261         const struct worktree *existing = NULL;
262         struct strbuf path = STRBUF_INIT;
263         struct strbuf sb = STRBUF_INIT;
264         static struct worktree **worktrees;
265         int i = 0;
266
267         if (worktrees)
268                 free_worktrees(worktrees);
269         worktrees = get_worktrees();
270
271         for (i = 0; worktrees[i]; i++) {
272                 struct worktree *wt = worktrees[i];
273
274                 if (wt->is_detached && !strcmp(symref, "HEAD")) {
275                         if (is_worktree_being_rebased(wt, target)) {
276                                 existing = wt;
277                                 break;
278                         }
279                         if (is_worktree_being_bisected(wt, target)) {
280                                 existing = wt;
281                                 break;
282                         }
283                 }
284
285                 strbuf_reset(&path);
286                 strbuf_reset(&sb);
287                 strbuf_addf(&path, "%s/%s",
288                             get_worktree_git_dir(wt),
289                             symref);
290
291                 if (parse_ref(path.buf, &sb, NULL)) {
292                         continue;
293                 }
294
295                 if (!strcmp(sb.buf, target)) {
296                         existing = wt;
297                         break;
298                 }
299         }
300
301         strbuf_release(&path);
302         strbuf_release(&sb);
303
304         return existing;
305 }