git-remote-mediawiki: get rid of O(N^2) loop
[git] / tree.c
1 #include "cache.h"
2 #include "cache-tree.h"
3 #include "tree.h"
4 #include "blob.h"
5 #include "commit.h"
6 #include "tag.h"
7 #include "tree-walk.h"
8
9 const char *tree_type = "tree";
10
11 static int read_one_entry_opt(const unsigned char *sha1, const char *base, int baselen, const char *pathname, unsigned mode, int stage, int opt)
12 {
13         int len;
14         unsigned int size;
15         struct cache_entry *ce;
16
17         if (S_ISDIR(mode))
18                 return READ_TREE_RECURSIVE;
19
20         len = strlen(pathname);
21         size = cache_entry_size(baselen + len);
22         ce = xcalloc(1, size);
23
24         ce->ce_mode = create_ce_mode(mode);
25         ce->ce_flags = create_ce_flags(baselen + len, stage);
26         memcpy(ce->name, base, baselen);
27         memcpy(ce->name + baselen, pathname, len+1);
28         hashcpy(ce->sha1, sha1);
29         return add_cache_entry(ce, opt);
30 }
31
32 static int read_one_entry(const unsigned char *sha1, const char *base, int baselen, const char *pathname, unsigned mode, int stage, void *context)
33 {
34         return read_one_entry_opt(sha1, base, baselen, pathname, mode, stage,
35                                   ADD_CACHE_OK_TO_ADD|ADD_CACHE_SKIP_DFCHECK);
36 }
37
38 /*
39  * This is used when the caller knows there is no existing entries at
40  * the stage that will conflict with the entry being added.
41  */
42 static int read_one_entry_quick(const unsigned char *sha1, const char *base, int baselen, const char *pathname, unsigned mode, int stage, void *context)
43 {
44         return read_one_entry_opt(sha1, base, baselen, pathname, mode, stage,
45                                   ADD_CACHE_JUST_APPEND);
46 }
47
48 static int read_tree_1(struct tree *tree, struct strbuf *base,
49                        int stage, struct pathspec *pathspec,
50                        read_tree_fn_t fn, void *context)
51 {
52         struct tree_desc desc;
53         struct name_entry entry;
54         unsigned char sha1[20];
55         int len, oldlen = base->len;
56         enum interesting retval = entry_not_interesting;
57
58         if (parse_tree(tree))
59                 return -1;
60
61         init_tree_desc(&desc, tree->buffer, tree->size);
62
63         while (tree_entry(&desc, &entry)) {
64                 if (retval != all_entries_interesting) {
65                         retval = tree_entry_interesting(&entry, base, 0, pathspec);
66                         if (retval == all_entries_not_interesting)
67                                 break;
68                         if (retval == entry_not_interesting)
69                                 continue;
70                 }
71
72                 switch (fn(entry.sha1, base->buf, base->len,
73                            entry.path, entry.mode, stage, context)) {
74                 case 0:
75                         continue;
76                 case READ_TREE_RECURSIVE:
77                         break;
78                 default:
79                         return -1;
80                 }
81
82                 if (S_ISDIR(entry.mode))
83                         hashcpy(sha1, entry.sha1);
84                 else if (S_ISGITLINK(entry.mode)) {
85                         struct commit *commit;
86
87                         commit = lookup_commit(entry.sha1);
88                         if (!commit)
89                                 die("Commit %s in submodule path %s%s not found",
90                                     sha1_to_hex(entry.sha1),
91                                     base->buf, entry.path);
92
93                         if (parse_commit(commit))
94                                 die("Invalid commit %s in submodule path %s%s",
95                                     sha1_to_hex(entry.sha1),
96                                     base->buf, entry.path);
97
98                         hashcpy(sha1, commit->tree->object.sha1);
99                 }
100                 else
101                         continue;
102
103                 len = tree_entry_len(&entry);
104                 strbuf_add(base, entry.path, len);
105                 strbuf_addch(base, '/');
106                 retval = read_tree_1(lookup_tree(sha1),
107                                      base, stage, pathspec,
108                                      fn, context);
109                 strbuf_setlen(base, oldlen);
110                 if (retval)
111                         return -1;
112         }
113         return 0;
114 }
115
116 int read_tree_recursive(struct tree *tree,
117                         const char *base, int baselen,
118                         int stage, struct pathspec *pathspec,
119                         read_tree_fn_t fn, void *context)
120 {
121         struct strbuf sb = STRBUF_INIT;
122         int ret;
123
124         strbuf_add(&sb, base, baselen);
125         ret = read_tree_1(tree, &sb, stage, pathspec, fn, context);
126         strbuf_release(&sb);
127         return ret;
128 }
129
130 static int cmp_cache_name_compare(const void *a_, const void *b_)
131 {
132         const struct cache_entry *ce1, *ce2;
133
134         ce1 = *((const struct cache_entry **)a_);
135         ce2 = *((const struct cache_entry **)b_);
136         return cache_name_compare(ce1->name, ce1->ce_flags,
137                                   ce2->name, ce2->ce_flags);
138 }
139
140 int read_tree(struct tree *tree, int stage, struct pathspec *match)
141 {
142         read_tree_fn_t fn = NULL;
143         int i, err;
144
145         /*
146          * Currently the only existing callers of this function all
147          * call it with stage=1 and after making sure there is nothing
148          * at that stage; we could always use read_one_entry_quick().
149          *
150          * But when we decide to straighten out git-read-tree not to
151          * use unpack_trees() in some cases, this will probably start
152          * to matter.
153          */
154
155         /*
156          * See if we have cache entry at the stage.  If so,
157          * do it the original slow way, otherwise, append and then
158          * sort at the end.
159          */
160         for (i = 0; !fn && i < active_nr; i++) {
161                 struct cache_entry *ce = active_cache[i];
162                 if (ce_stage(ce) == stage)
163                         fn = read_one_entry;
164         }
165
166         if (!fn)
167                 fn = read_one_entry_quick;
168         err = read_tree_recursive(tree, "", 0, stage, match, fn, NULL);
169         if (fn == read_one_entry || err)
170                 return err;
171
172         /*
173          * Sort the cache entry -- we need to nuke the cache tree, though.
174          */
175         cache_tree_free(&active_cache_tree);
176         qsort(active_cache, active_nr, sizeof(active_cache[0]),
177               cmp_cache_name_compare);
178         return 0;
179 }
180
181 struct tree *lookup_tree(const unsigned char *sha1)
182 {
183         struct object *obj = lookup_object(sha1);
184         if (!obj)
185                 return create_object(sha1, OBJ_TREE, alloc_tree_node());
186         if (!obj->type)
187                 obj->type = OBJ_TREE;
188         if (obj->type != OBJ_TREE) {
189                 error("Object %s is a %s, not a tree",
190                       sha1_to_hex(sha1), typename(obj->type));
191                 return NULL;
192         }
193         return (struct tree *) obj;
194 }
195
196 int parse_tree_buffer(struct tree *item, void *buffer, unsigned long size)
197 {
198         if (item->object.parsed)
199                 return 0;
200         item->object.parsed = 1;
201         item->buffer = buffer;
202         item->size = size;
203
204         return 0;
205 }
206
207 int parse_tree(struct tree *item)
208 {
209          enum object_type type;
210          void *buffer;
211          unsigned long size;
212
213         if (item->object.parsed)
214                 return 0;
215         buffer = read_sha1_file(item->object.sha1, &type, &size);
216         if (!buffer)
217                 return error("Could not read %s",
218                              sha1_to_hex(item->object.sha1));
219         if (type != OBJ_TREE) {
220                 free(buffer);
221                 return error("Object %s not a tree",
222                              sha1_to_hex(item->object.sha1));
223         }
224         return parse_tree_buffer(item, buffer, size);
225 }
226
227 struct tree *parse_tree_indirect(const unsigned char *sha1)
228 {
229         struct object *obj = parse_object(sha1);
230         do {
231                 if (!obj)
232                         return NULL;
233                 if (obj->type == OBJ_TREE)
234                         return (struct tree *) obj;
235                 else if (obj->type == OBJ_COMMIT)
236                         obj = &(((struct commit *) obj)->tree->object);
237                 else if (obj->type == OBJ_TAG)
238                         obj = ((struct tag *) obj)->tagged;
239                 else
240                         return NULL;
241                 if (!obj->parsed)
242                         parse_object(obj->sha1);
243         } while (1);
244 }