git-tar-tree: documentation update
[git.git] / fetch.c
1 #include "fetch.h"
2
3 #include "cache.h"
4 #include "commit.h"
5 #include "tree.h"
6 #include "tree-walk.h"
7 #include "tag.h"
8 #include "blob.h"
9 #include "refs.h"
10
11 const char *write_ref = NULL;
12 const char *write_ref_log_details = NULL;
13
14 int get_tree = 0;
15 int get_history = 0;
16 int get_all = 0;
17 int get_verbosely = 0;
18 int get_recover = 0;
19 static unsigned char current_commit_sha1[20];
20
21 void pull_say(const char *fmt, const char *hex) 
22 {
23         if (get_verbosely)
24                 fprintf(stderr, fmt, hex);
25 }
26
27 static void report_missing(const char *what, const unsigned char *missing)
28 {
29         char missing_hex[41];
30
31         strcpy(missing_hex, sha1_to_hex(missing));;
32         fprintf(stderr,
33                 "Cannot obtain needed %s %s\nwhile processing commit %s.\n",
34                 what, missing_hex, sha1_to_hex(current_commit_sha1));
35 }
36
37 static int process(struct object *obj);
38
39 static int process_tree(struct tree *tree)
40 {
41         struct tree_desc desc;
42         struct name_entry entry;
43
44         if (parse_tree(tree))
45                 return -1;
46
47         desc.buf = tree->buffer;
48         desc.size = tree->size;
49         while (tree_entry(&desc, &entry)) {
50                 struct object *obj = NULL;
51
52                 if (S_ISDIR(entry.mode)) {
53                         struct tree *tree = lookup_tree(entry.sha1);
54                         if (tree)
55                                 obj = &tree->object;
56                 }
57                 else {
58                         struct blob *blob = lookup_blob(entry.sha1);
59                         if (blob)
60                                 obj = &blob->object;
61                 }
62                 if (!obj || process(obj))
63                         return -1;
64         }
65         free(tree->buffer);
66         tree->buffer = NULL;
67         tree->size = 0;
68         return 0;
69 }
70
71 #define COMPLETE        (1U << 0)
72 #define SEEN            (1U << 1)
73 #define TO_SCAN         (1U << 2)
74
75 static struct commit_list *complete = NULL;
76
77 static int process_commit(struct commit *commit)
78 {
79         if (parse_commit(commit))
80                 return -1;
81
82         while (complete && complete->item->date >= commit->date) {
83                 pop_most_recent_commit(&complete, COMPLETE);
84         }
85
86         if (commit->object.flags & COMPLETE)
87                 return 0;
88
89         memcpy(current_commit_sha1, commit->object.sha1, 20);
90
91         pull_say("walk %s\n", sha1_to_hex(commit->object.sha1));
92
93         if (get_tree) {
94                 if (process(&commit->tree->object))
95                         return -1;
96                 if (!get_all)
97                         get_tree = 0;
98         }
99         if (get_history) {
100                 struct commit_list *parents = commit->parents;
101                 for (; parents; parents = parents->next) {
102                         if (process(&parents->item->object))
103                                 return -1;
104                 }
105         }
106         return 0;
107 }
108
109 static int process_tag(struct tag *tag)
110 {
111         if (parse_tag(tag))
112                 return -1;
113         return process(tag->tagged);
114 }
115
116 static struct object_list *process_queue = NULL;
117 static struct object_list **process_queue_end = &process_queue;
118
119 static int process_object(struct object *obj)
120 {
121         if (obj->type == TYPE_COMMIT) {
122                 if (process_commit((struct commit *)obj))
123                         return -1;
124                 return 0;
125         }
126         if (obj->type == TYPE_TREE) {
127                 if (process_tree((struct tree *)obj))
128                         return -1;
129                 return 0;
130         }
131         if (obj->type == TYPE_BLOB) {
132                 return 0;
133         }
134         if (obj->type == TYPE_TAG) {
135                 if (process_tag((struct tag *)obj))
136                         return -1;
137                 return 0;
138         }
139         return error("Unable to determine requirements "
140                      "of type %s for %s",
141                      typename(obj->type), sha1_to_hex(obj->sha1));
142 }
143
144 static int process(struct object *obj)
145 {
146         if (obj->flags & SEEN)
147                 return 0;
148         obj->flags |= SEEN;
149
150         if (has_sha1_file(obj->sha1)) {
151                 /* We already have it, so we should scan it now. */
152                 obj->flags |= TO_SCAN;
153         }
154         else {
155                 if (obj->flags & COMPLETE)
156                         return 0;
157                 prefetch(obj->sha1);
158         }
159                 
160         object_list_insert(obj, process_queue_end);
161         process_queue_end = &(*process_queue_end)->next;
162         return 0;
163 }
164
165 static int loop(void)
166 {
167         struct object_list *elem;
168
169         while (process_queue) {
170                 struct object *obj = process_queue->item;
171                 elem = process_queue;
172                 process_queue = elem->next;
173                 free(elem);
174                 if (!process_queue)
175                         process_queue_end = &process_queue;
176
177                 /* If we are not scanning this object, we placed it in
178                  * the queue because we needed to fetch it first.
179                  */
180                 if (! (obj->flags & TO_SCAN)) {
181                         if (fetch(obj->sha1)) {
182                                 report_missing(typename(obj->type), obj->sha1);
183                                 return -1;
184                         }
185                 }
186                 if (!obj->type)
187                         parse_object(obj->sha1);
188                 if (process_object(obj))
189                         return -1;
190         }
191         return 0;
192 }
193
194 static int interpret_target(char *target, unsigned char *sha1)
195 {
196         if (!get_sha1_hex(target, sha1))
197                 return 0;
198         if (!check_ref_format(target)) {
199                 if (!fetch_ref(target, sha1)) {
200                         return 0;
201                 }
202         }
203         return -1;
204 }
205
206 static int mark_complete(const char *path, const unsigned char *sha1)
207 {
208         struct commit *commit = lookup_commit_reference_gently(sha1, 1);
209         if (commit) {
210                 commit->object.flags |= COMPLETE;
211                 insert_by_date(commit, &complete);
212         }
213         return 0;
214 }
215
216 int pull(char *target)
217 {
218         struct ref_lock *lock = NULL;
219         unsigned char sha1[20];
220         char *msg;
221         int ret;
222
223         save_commit_buffer = 0;
224         track_object_refs = 0;
225         if (write_ref) {
226                 lock = lock_ref_sha1(write_ref, NULL, 0);
227                 if (!lock) {
228                         error("Can't lock ref %s", write_ref);
229                         return -1;
230                 }
231         }
232
233         if (!get_recover)
234                 for_each_ref(mark_complete);
235
236         if (interpret_target(target, sha1)) {
237                 error("Could not interpret %s as something to pull", target);
238                 if (lock)
239                         unlock_ref(lock);
240                 return -1;
241         }
242         if (process(lookup_unknown_object(sha1))) {
243                 if (lock)
244                         unlock_ref(lock);
245                 return -1;
246         }
247         if (loop()) {
248                 if (lock)
249                         unlock_ref(lock);
250                 return -1;
251         }
252
253         if (write_ref) {
254                 if (write_ref_log_details) {
255                         msg = xmalloc(strlen(write_ref_log_details) + 12);
256                         sprintf(msg, "fetch from %s", write_ref_log_details);
257                 }
258                 else
259                         msg = NULL;
260                 ret = write_ref_sha1(lock, sha1, msg ? msg : "fetch (unknown)");
261                 if (msg)
262                         free(msg);
263                 return ret;
264         }
265         return 0;
266 }