git-tag: update usage string and documentation.
[git.git] / fetch.c
1 #include "fetch.h"
2
3 #include "cache.h"
4 #include "commit.h"
5 #include "tree.h"
6 #include "tag.h"
7 #include "blob.h"
8 #include "refs.h"
9
10 const char *write_ref = NULL;
11
12 const unsigned char *current_ref = 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_entry_list *entry;
42
43         if (parse_tree(tree))
44                 return -1;
45
46         entry = tree->entries;
47         tree->entries = NULL;
48         while (entry) {
49                 struct tree_entry_list *next = entry->next;
50                 if (process(entry->item.any))
51                         return -1;
52                 free(entry->name);
53                 free(entry);
54                 entry = next;
55         }
56         return 0;
57 }
58
59 #define COMPLETE        (1U << 0)
60 #define SEEN            (1U << 1)
61 #define TO_SCAN         (1U << 2)
62
63 static struct commit_list *complete = NULL;
64
65 static int process_commit(struct commit *commit)
66 {
67         if (parse_commit(commit))
68                 return -1;
69
70         while (complete && complete->item->date >= commit->date) {
71                 pop_most_recent_commit(&complete, COMPLETE);
72         }
73
74         if (commit->object.flags & COMPLETE)
75                 return 0;
76
77         memcpy(current_commit_sha1, commit->object.sha1, 20);
78
79         pull_say("walk %s\n", sha1_to_hex(commit->object.sha1));
80
81         if (get_tree) {
82                 if (process(&commit->tree->object))
83                         return -1;
84                 if (!get_all)
85                         get_tree = 0;
86         }
87         if (get_history) {
88                 struct commit_list *parents = commit->parents;
89                 for (; parents; parents = parents->next) {
90                         if (process(&parents->item->object))
91                                 return -1;
92                 }
93         }
94         return 0;
95 }
96
97 static int process_tag(struct tag *tag)
98 {
99         if (parse_tag(tag))
100                 return -1;
101         return process(tag->tagged);
102 }
103
104 static struct object_list *process_queue = NULL;
105 static struct object_list **process_queue_end = &process_queue;
106
107 static int process_object(struct object *obj)
108 {
109         if (obj->type == commit_type) {
110                 if (process_commit((struct commit *)obj))
111                         return -1;
112                 return 0;
113         }
114         if (obj->type == tree_type) {
115                 if (process_tree((struct tree *)obj))
116                         return -1;
117                 return 0;
118         }
119         if (obj->type == blob_type) {
120                 return 0;
121         }
122         if (obj->type == tag_type) {
123                 if (process_tag((struct tag *)obj))
124                         return -1;
125                 return 0;
126         }
127         return error("Unable to determine requirements "
128                      "of type %s for %s",
129                      obj->type, sha1_to_hex(obj->sha1));
130 }
131
132 static int process(struct object *obj)
133 {
134         if (obj->flags & SEEN)
135                 return 0;
136         obj->flags |= SEEN;
137
138         if (has_sha1_file(obj->sha1)) {
139                 /* We already have it, so we should scan it now. */
140                 obj->flags |= TO_SCAN;
141         } else {
142                 if (obj->flags & COMPLETE)
143                         return 0;
144                 prefetch(obj->sha1);
145         }
146                 
147         object_list_insert(obj, process_queue_end);
148         process_queue_end = &(*process_queue_end)->next;
149         return 0;
150 }
151
152 static int loop(void)
153 {
154         struct object_list *elem;
155
156         while (process_queue) {
157                 struct object *obj = process_queue->item;
158                 elem = process_queue;
159                 process_queue = elem->next;
160                 free(elem);
161                 if (!process_queue)
162                         process_queue_end = &process_queue;
163
164                 /* If we are not scanning this object, we placed it in
165                  * the queue because we needed to fetch it first.
166                  */
167                 if (! (obj->flags & TO_SCAN)) {
168                         if (!has_sha1_file(obj->sha1) && fetch(obj->sha1)) {
169                                 report_missing(obj->type
170                                                ? obj->type
171                                                : "object", obj->sha1);
172                                 return -1;
173                         }
174                 }
175                 if (!obj->type)
176                         parse_object(obj->sha1);
177                 if (process_object(obj))
178                         return -1;
179         }
180         return 0;
181 }
182
183 static int interpret_target(char *target, unsigned char *sha1)
184 {
185         if (!get_sha1_hex(target, sha1))
186                 return 0;
187         if (!check_ref_format(target)) {
188                 if (!fetch_ref(target, sha1)) {
189                         return 0;
190                 }
191         }
192         return -1;
193 }
194
195 static int mark_complete(const char *path, const unsigned char *sha1)
196 {
197         struct commit *commit = lookup_commit_reference_gently(sha1, 1);
198         if (commit) {
199                 commit->object.flags |= COMPLETE;
200                 insert_by_date(commit, &complete);
201         }
202         return 0;
203 }
204
205 int pull(char *target)
206 {
207         unsigned char sha1[20];
208         int fd = -1;
209
210         save_commit_buffer = 0;
211         track_object_refs = 0;
212         if (write_ref && current_ref) {
213                 fd = lock_ref_sha1(write_ref, current_ref);
214                 if (fd < 0)
215                         return -1;
216         }
217
218         if (!get_recover) {
219                 for_each_ref(mark_complete);
220         }
221
222         if (interpret_target(target, sha1))
223                 return error("Could not interpret %s as something to pull",
224                              target);
225         if (process(lookup_unknown_object(sha1)))
226                 return -1;
227         if (loop())
228                 return -1;
229         
230         if (write_ref) {
231                 if (current_ref) {
232                         write_ref_sha1(write_ref, fd, sha1);
233                 } else {
234                         write_ref_sha1_unlocked(write_ref, sha1);
235                 }
236         }
237         return 0;
238 }