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 const char *type_names[] = {
  13         "none", "blob", "tree", "commit", "bad"
  14 };
  15
  16 int track_object_refs = 0;
  17
  18 static int hashtable_index(const unsigned char *sha1)
  19 {
  20         unsigned int i;
  21         memcpy(&i, sha1, sizeof(unsigned int));
  22         return (int)(i % obj_allocs);
  23 }
  24
  25 static int find_object(const unsigned char *sha1)
  26 {
  27         int i;
  28
  29         if (!objs)
  30                 return -1;
  31
  32         i = hashtable_index(sha1);
  33         while (objs[i]) {
  34                 if (memcmp(sha1, objs[i]->sha1, 20) == 0)
  35                         return i;
  36                 i++;
  37                 if (i == obj_allocs)
  38                         i = 0;
  39         }
  40         return -1 - i;
  41 }
  42
  43 struct object *lookup_object(const unsigned char *sha1)
  44 {
  45         int pos = find_object(sha1);
  46         if (pos >= 0)
  47                 return objs[pos];
  48         return NULL;
  49 }
  50
  51 void created_object(const unsigned char *sha1, struct object *obj)
  52 {
  53         int pos;
  54
  55         obj->parsed = 0;
  56         memcpy(obj->sha1, sha1, 20);
  57         obj->type = TYPE_NONE;
  58         obj->refs = NULL;
  59         obj->used = 0;
  60
  61         if (obj_allocs - 1 <= nr_objs * 2) {
  62                 int i, count = obj_allocs;
  63                 obj_allocs = (obj_allocs < 32 ? 32 : 2 * obj_allocs);
  64                 objs = xrealloc(objs, obj_allocs * sizeof(struct object *));
  65                 memset(objs + count, 0, (obj_allocs - count)
  66                                 * sizeof(struct object *));
  67                 for (i = 0; i < obj_allocs; i++)
  68                         if (objs[i]) {
  69                                 int j = find_object(objs[i]->sha1);
  70                                 if (j != i) {
  71                                         j = -1 - j;
  72                                         objs[j] = objs[i];
  73                                         objs[i] = NULL;
  74                                 }
  75                         }
  76         }
  77
  78         pos = find_object(sha1);
  79         if (pos >= 0)
  80                 die("Inserting %s twice\n", sha1_to_hex(sha1));
  81         pos = -pos-1;
  82
  83         objs[pos] = obj;
  84         nr_objs++;
  85 }
  86
  87 struct object_refs *alloc_object_refs(unsigned count)
  88 {
  89         struct object_refs *refs;
  90         size_t size = sizeof(*refs) + count*sizeof(struct object *);
  91
  92         refs = xcalloc(1, size);
  93         refs->count = count;
  94         return refs;
  95 }
  96
  97 static int compare_object_pointers(const void *a, const void *b)
  98 {
  99         const struct object * const *pa = a;
 100         const struct object * const *pb = b;
 101         if (*pa == *pb)
 102                 return 0;
 103         else if (*pa < *pb)
 104                 return -1;
 105         else
 106                 return 1;
 107 }
 108
 109 void set_object_refs(struct object *obj, struct object_refs *refs)
 110 {
 111         unsigned int i, j;
 112
 113         /* Do not install empty list of references */
 114         if (refs->count < 1) {
 115                 free(refs);
 116                 return;
 117         }
 118
 119         /* Sort the list and filter out duplicates */
 120         qsort(refs->ref, refs->count, sizeof(refs->ref[0]),
 121               compare_object_pointers);
 122         for (i = j = 1; i < refs->count; i++) {
 123                 if (refs->ref[i] != refs->ref[i - 1])
 124                         refs->ref[j++] = refs->ref[i];
 125         }
 126         if (j < refs->count) {
 127                 /* Duplicates were found - reallocate list */
 128                 size_t size = sizeof(*refs) + j*sizeof(struct object *);
 129                 refs->count = j;
 130                 refs = xrealloc(refs, size);
 131         }
 132
 133         for (i = 0; i < refs->count; i++)
 134                 refs->ref[i]->used = 1;
 135         obj->refs = refs;
 136 }
 137
 138 void mark_reachable(struct object *obj, unsigned int mask)
 139 {
 140         if (!track_object_refs)
 141                 die("cannot do reachability with object refs turned off");
 142         /* If we've been here already, don't bother */
 143         if (obj->flags & mask)
 144                 return;
 145         obj->flags |= mask;
 146         if (obj->refs) {
 147                 const struct object_refs *refs = obj->refs;
 148                 unsigned i;
 149                 for (i = 0; i < refs->count; i++)
 150                         mark_reachable(refs->ref[i], mask);
 151         }
 152 }
 153
 154 struct object *lookup_object_type(const unsigned char *sha1, const char *type)
 155 {
 156         if (!type) {
 157                 return lookup_unknown_object(sha1);
 158         } else if (!strcmp(type, blob_type)) {
 159                 return &lookup_blob(sha1)->object;
 160         } else if (!strcmp(type, tree_type)) {
 161                 return &lookup_tree(sha1)->object;
 162         } else if (!strcmp(type, commit_type)) {
 163                 return &lookup_commit(sha1)->object;
 164         } else if (!strcmp(type, tag_type)) {
 165                 return &lookup_tag(sha1)->object;
 166         } else {
 167                 error("Unknown type %s", type);
 168                 return NULL;
 169         }
 170 }
 171
 172 union any_object {
 173         struct object object;
 174         struct commit commit;
 175         struct tree tree;
 176         struct blob blob;
 177         struct tag tag;
 178 };
 179
 180 struct object *lookup_unknown_object(const unsigned char *sha1)
 181 {
 182         struct object *obj = lookup_object(sha1);
 183         if (!obj) {
 184                 union any_object *ret = xcalloc(1, sizeof(*ret));
 185                 created_object(sha1, &ret->object);
 186                 ret->object.type = TYPE_NONE;
 187                 return &ret->object;
 188         }
 189         return obj;
 190 }
 191
 192 struct object *parse_object(const unsigned char *sha1)
 193 {
 194         unsigned long size;
 195         char type[20];
 196         void *buffer = read_sha1_file(sha1, type, &size);
 197         if (buffer) {
 198                 struct object *obj;
 199                 if (check_sha1_signature(sha1, buffer, size, type) < 0)
 200                         printf("sha1 mismatch %s\n", sha1_to_hex(sha1));
 201                 if (!strcmp(type, blob_type)) {
 202                         struct blob *blob = lookup_blob(sha1);
 203                         parse_blob_buffer(blob, buffer, size);
 204                         obj = &blob->object;
 205                 } else if (!strcmp(type, tree_type)) {
 206                         struct tree *tree = lookup_tree(sha1);
 207                         obj = &tree->object;
 208                         if (!tree->object.parsed) {
 209                                 parse_tree_buffer(tree, buffer, size);
 210                                 buffer = NULL;
 211                         }
 212                 } else if (!strcmp(type, commit_type)) {
 213                         struct commit *commit = lookup_commit(sha1);
 214                         parse_commit_buffer(commit, buffer, size);
 215                         if (!commit->buffer) {
 216                                 commit->buffer = buffer;
 217                                 buffer = NULL;
 218                         }
 219                         obj = &commit->object;
 220                 } else if (!strcmp(type, tag_type)) {
 221                         struct tag *tag = lookup_tag(sha1);
 222                         parse_tag_buffer(tag, buffer, size);
 223                         obj = &tag->object;
 224                 } else {
 225                         obj = NULL;
 226                 }
 227                 free(buffer);
 228                 return obj;
 229         }
 230         return NULL;
 231 }
 232
 233 struct object_list *object_list_insert(struct object *item,
 234                                        struct object_list **list_p)
 235 {
 236         struct object_list *new_list = xmalloc(sizeof(struct object_list));
 237         new_list->item = item;
 238         new_list->next = *list_p;
 239         *list_p = new_list;
 240         return new_list;
 241 }
 242
 243 void object_list_append(struct object *item,
 244                         struct object_list **list_p)
 245 {
 246         while (*list_p) {
 247                 list_p = &((*list_p)->next);
 248         }
 249         *list_p = xmalloc(sizeof(struct object_list));
 250         (*list_p)->next = NULL;
 251         (*list_p)->item = item;
 252 }
 253
 254 unsigned object_list_length(struct object_list *list)
 255 {
 256         unsigned ret = 0;
 257         while (list) {
 258                 list = list->next;
 259                 ret++;
 260         }
 261         return ret;
 262 }
 263
 264 int object_list_contains(struct object_list *list, struct object *obj)
 265 {
 266         while (list) {
 267                 if (list->item == obj)
 268                         return 1;
 269                 list = list->next;
 270         }
 271         return 0;
 272 }