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