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_type)) {
 200                         struct blob *blob = lookup_blob(sha1);
 201                         parse_blob_buffer(blob, buffer, size);
 202                         obj = &blob->object;
 203                 } else if (!strcmp(type, tree_type)) {
 204                         struct tree *tree = lookup_tree(sha1);
 205                         parse_tree_buffer(tree, buffer, size);
 206                         obj = &tree->object;
 207                 } else if (!strcmp(type, commit_type)) {
 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_type)) {
 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 }