verify-pack -v: show delta-chain histogram.
[git] / object.c
1 #include "cache.h"
2 #include "object.h"
3 #include "blob.h"
4 #include "tree.h"
5 #include "commit.h"
6 #include "tag.h"
7
8 struct object **objs;
9 static int nr_objs;
10 int obj_allocs;
11
12 int track_object_refs = 1;
13
14 static int hashtable_index(const unsigned char *sha1)
15 {
16         unsigned int i;
17         memcpy(&i, sha1, sizeof(unsigned int));
18         return (int)(i % obj_allocs);
19 }
20
21 static int find_object(const unsigned char *sha1)
22 {
23         int i;
24
25         if (!objs)
26                 return -1;
27
28         i = hashtable_index(sha1);
29         while (objs[i]) {
30                 if (memcmp(sha1, objs[i]->sha1, 20) == 0)
31                         return i;
32                 i++;
33                 if (i == obj_allocs)
34                         i = 0;
35         }
36         return -1 - i;
37 }
38
39 struct object *lookup_object(const unsigned char *sha1)
40 {
41         int pos = find_object(sha1);
42         if (pos >= 0)
43                 return objs[pos];
44         return NULL;
45 }
46
47 void created_object(const unsigned char *sha1, struct object *obj)
48 {
49         int pos;
50
51         obj->parsed = 0;
52         memcpy(obj->sha1, sha1, 20);
53         obj->type = NULL;
54         obj->refs = NULL;
55         obj->used = 0;
56
57         if (obj_allocs - 1 <= nr_objs * 2) {
58                 int i, count = obj_allocs;
59                 obj_allocs = (obj_allocs < 32 ? 32 : 2 * obj_allocs);
60                 objs = xrealloc(objs, obj_allocs * sizeof(struct object *));
61                 memset(objs + count, 0, (obj_allocs - count)
62                                 * sizeof(struct object *));
63                 for (i = 0; i < obj_allocs; i++)
64                         if (objs[i]) {
65                                 int j = find_object(objs[i]->sha1);
66                                 if (j != i) {
67                                         j = -1 - j;
68                                         objs[j] = objs[i];
69                                         objs[i] = NULL;
70                                 }
71                         }
72         }
73
74         pos = find_object(sha1);
75         if (pos >= 0)
76                 die("Inserting %s twice\n", sha1_to_hex(sha1));
77         pos = -pos-1;
78
79         objs[pos] = obj;
80         nr_objs++;
81 }
82
83 struct object_refs *alloc_object_refs(unsigned count)
84 {
85         struct object_refs *refs;
86         size_t size = sizeof(*refs) + count*sizeof(struct object *);
87
88         refs = xmalloc(size);
89         memset(refs, 0, size);
90         refs->count = count;
91         return refs;
92 }
93
94 static int compare_object_pointers(const void *a, const void *b)
95 {
96         const struct object * const *pa = a;
97         const struct object * const *pb = b;
98         if (*pa == *pb)
99                 return 0;
100         else if (*pa < *pb)
101                 return -1;
102         else
103                 return 1;
104 }
105
106 void set_object_refs(struct object *obj, struct object_refs *refs)
107 {
108         unsigned int i, j;
109
110         /* Do not install empty list of references */
111         if (refs->count < 1) {
112                 free(refs);
113                 return;
114         }
115
116         /* Sort the list and filter out duplicates */
117         qsort(refs->ref, refs->count, sizeof(refs->ref[0]),
118               compare_object_pointers);
119         for (i = j = 1; i < refs->count; i++) {
120                 if (refs->ref[i] != refs->ref[i - 1])
121                         refs->ref[j++] = refs->ref[i];
122         }
123         if (j < refs->count) {
124                 /* Duplicates were found - reallocate list */
125                 size_t size = sizeof(*refs) + j*sizeof(struct object *);
126                 refs->count = j;
127                 refs = xrealloc(refs, size);
128         }
129
130         for (i = 0; i < refs->count; i++)
131                 refs->ref[i]->used = 1;
132         obj->refs = refs;
133 }
134
135 void mark_reachable(struct object *obj, unsigned int mask)
136 {
137         if (!track_object_refs)
138                 die("cannot do reachability with object refs turned off");
139         /* If we've been here already, don't bother */
140         if (obj->flags & mask)
141                 return;
142         obj->flags |= mask;
143         if (obj->refs) {
144                 const struct object_refs *refs = obj->refs;
145                 unsigned i;
146                 for (i = 0; i < refs->count; i++)
147                         mark_reachable(refs->ref[i], mask);
148         }
149 }
150
151 struct object *lookup_object_type(const unsigned char *sha1, const char *type)
152 {
153         if (!type) {
154                 return lookup_unknown_object(sha1);
155         } else if (!strcmp(type, blob_type)) {
156                 return &lookup_blob(sha1)->object;
157         } else if (!strcmp(type, tree_type)) {
158                 return &lookup_tree(sha1)->object;
159         } else if (!strcmp(type, commit_type)) {
160                 return &lookup_commit(sha1)->object;
161         } else if (!strcmp(type, tag_type)) {
162                 return &lookup_tag(sha1)->object;
163         } else {
164                 error("Unknown type %s", type);
165                 return NULL;
166         }
167 }
168
169 union any_object {
170         struct object object;
171         struct commit commit;
172         struct tree tree;
173         struct blob blob;
174         struct tag tag;
175 };
176
177 struct object *lookup_unknown_object(const unsigned char *sha1)
178 {
179         struct object *obj = lookup_object(sha1);
180         if (!obj) {
181                 union any_object *ret = xmalloc(sizeof(*ret));
182                 memset(ret, 0, sizeof(*ret));
183                 created_object(sha1, &ret->object);
184                 ret->object.type = NULL;
185                 return &ret->object;
186         }
187         return obj;
188 }
189
190 struct object *parse_object(const unsigned char *sha1)
191 {
192         unsigned long size;
193         char type[20];
194         void *buffer = read_sha1_file(sha1, type, &size);
195         if (buffer) {
196                 struct object *obj;
197                 if (check_sha1_signature(sha1, buffer, size, type) < 0)
198                         printf("sha1 mismatch %s\n", sha1_to_hex(sha1));
199                 if (!strcmp(type, "blob")) {
200                         struct blob *blob = lookup_blob(sha1);
201                         parse_blob_buffer(blob, buffer, size);
202                         obj = &blob->object;
203                 } else if (!strcmp(type, "tree")) {
204                         struct tree *tree = lookup_tree(sha1);
205                         parse_tree_buffer(tree, buffer, size);
206                         obj = &tree->object;
207                 } else if (!strcmp(type, "commit")) {
208                         struct commit *commit = lookup_commit(sha1);
209                         parse_commit_buffer(commit, buffer, size);
210                         if (!commit->buffer) {
211                                 commit->buffer = buffer;
212                                 buffer = NULL;
213                         }
214                         obj = &commit->object;
215                 } else if (!strcmp(type, "tag")) {
216                         struct tag *tag = lookup_tag(sha1);
217                         parse_tag_buffer(tag, buffer, size);
218                         obj = &tag->object;
219                 } else {
220                         obj = NULL;
221                 }
222                 free(buffer);
223                 return obj;
224         }
225         return NULL;
226 }
227
228 struct object_list *object_list_insert(struct object *item,
229                                        struct object_list **list_p)
230 {
231         struct object_list *new_list = xmalloc(sizeof(struct object_list));
232         new_list->item = item;
233         new_list->next = *list_p;
234         *list_p = new_list;
235         return new_list;
236 }
237
238 void object_list_append(struct object *item,
239                         struct object_list **list_p)
240 {
241         while (*list_p) {
242                 list_p = &((*list_p)->next);
243         }
244         *list_p = xmalloc(sizeof(struct object_list));
245         (*list_p)->next = NULL;
246         (*list_p)->item = item;
247 }
248
249 unsigned object_list_length(struct object_list *list)
250 {
251         unsigned ret = 0;
252         while (list) {
253                 list = list->next;
254                 ret++;
255         }
256         return ret;
257 }
258
259 int object_list_contains(struct object_list *list, struct object *obj)
260 {
261         while (list) {
262                 if (list->item == obj)
263                         return 1;
264                 list = list->next;
265         }
266         return 0;
267 }