object.c

   1 #include "object.h"
   2 #include "blob.h"
   3 #include "tree.h"
   4 #include "commit.h"
   5 #include "cache.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         return *pa - *pb;
  86 }
  87
  88 void set_object_refs(struct object *obj, struct object_refs *refs)
  89 {
  90         unsigned int i, j;
  91
  92         /* Do not install empty list of references */
  93         if (refs->count < 1) {
  94                 free(refs);
  95                 return;
  96         }
  97
  98         /* Sort the list and filter out duplicates */
  99         qsort(refs->ref, refs->count, sizeof(refs->ref[0]),
 100               compare_object_pointers);
 101         for (i = j = 1; i < refs->count; i++) {
 102                 if (refs->ref[i] != refs->ref[i - 1])
 103                         refs->ref[j++] = refs->ref[i];
 104         }
 105         if (j < refs->count) {
 106                 /* Duplicates were found - reallocate list */
 107                 size_t size = sizeof(*refs) + j*sizeof(struct object *);
 108                 refs->count = j;
 109                 refs = xrealloc(refs, size);
 110         }
 111
 112         for (i = 0; i < refs->count; i++)
 113                 refs->ref[i]->used = 1;
 114         obj->refs = refs;
 115 }
 116
 117 void mark_reachable(struct object *obj, unsigned int mask)
 118 {
 119         if (!track_object_refs)
 120                 die("cannot do reachability with object refs turned off");
 121         /* If we've been here already, don't bother */
 122         if (obj->flags & mask)
 123                 return;
 124         obj->flags |= mask;
 125         if (obj->refs) {
 126                 const struct object_refs *refs = obj->refs;
 127                 unsigned i;
 128                 for (i = 0; i < refs->count; i++)
 129                         mark_reachable(refs->ref[i], mask);
 130         }
 131 }
 132
 133 struct object *lookup_object_type(const unsigned char *sha1, const char *type)
 134 {
 135         if (!type) {
 136                 return lookup_unknown_object(sha1);
 137         } else if (!strcmp(type, blob_type)) {
 138                 return &lookup_blob(sha1)->object;
 139         } else if (!strcmp(type, tree_type)) {
 140                 return &lookup_tree(sha1)->object;
 141         } else if (!strcmp(type, commit_type)) {
 142                 return &lookup_commit(sha1)->object;
 143         } else if (!strcmp(type, tag_type)) {
 144                 return &lookup_tag(sha1)->object;
 145         } else {
 146                 error("Unknown type %s", type);
 147                 return NULL;
 148         }
 149 }
 150
 151 union any_object {
 152         struct object object;
 153         struct commit commit;
 154         struct tree tree;
 155         struct blob blob;
 156         struct tag tag;
 157 };
 158
 159 struct object *lookup_unknown_object(const unsigned char *sha1)
 160 {
 161         struct object *obj = lookup_object(sha1);
 162         if (!obj) {
 163                 union any_object *ret = xmalloc(sizeof(*ret));
 164                 memset(ret, 0, sizeof(*ret));
 165                 created_object(sha1, &ret->object);
 166                 ret->object.type = NULL;
 167                 return &ret->object;
 168         }
 169         return obj;
 170 }
 171
 172 struct object *parse_object(const unsigned char *sha1)
 173 {
 174         unsigned long size;
 175         char type[20];
 176         void *buffer = read_sha1_file(sha1, type, &size);
 177         if (buffer) {
 178                 struct object *obj;
 179                 if (check_sha1_signature(sha1, buffer, size, type) < 0)
 180                         printf("sha1 mismatch %s\n", sha1_to_hex(sha1));
 181                 if (!strcmp(type, "blob")) {
 182                         struct blob *blob = lookup_blob(sha1);
 183                         parse_blob_buffer(blob, buffer, size);
 184                         obj = &blob->object;
 185                 } else if (!strcmp(type, "tree")) {
 186                         struct tree *tree = lookup_tree(sha1);
 187                         parse_tree_buffer(tree, buffer, size);
 188                         obj = &tree->object;
 189                 } else if (!strcmp(type, "commit")) {
 190                         struct commit *commit = lookup_commit(sha1);
 191                         parse_commit_buffer(commit, buffer, size);
 192                         if (!commit->buffer) {
 193                                 commit->buffer = buffer;
 194                                 buffer = NULL;
 195                         }
 196                         obj = &commit->object;
 197                 } else if (!strcmp(type, "tag")) {
 198                         struct tag *tag = lookup_tag(sha1);
 199                         parse_tag_buffer(tag, buffer, size);
 200                         obj = &tag->object;
 201                 } else {
 202                         obj = NULL;
 203                 }
 204                 free(buffer);
 205                 return obj;
 206         }
 207         return NULL;
 208 }
 209
 210 struct object_list *object_list_insert(struct object *item,
 211                                        struct object_list **list_p)
 212 {
 213         struct object_list *new_list = xmalloc(sizeof(struct object_list));
 214         new_list->item = item;
 215         new_list->next = *list_p;
 216         *list_p = new_list;
 217         return new_list;
 218 }
 219
 220 void object_list_append(struct object *item,
 221                         struct object_list **list_p)
 222 {
 223         while (*list_p) {
 224                 list_p = &((*list_p)->next);
 225         }
 226         *list_p = xmalloc(sizeof(struct object_list));
 227         (*list_p)->next = NULL;
 228         (*list_p)->item = item;
 229 }
 230
 231 unsigned object_list_length(struct object_list *list)
 232 {
 233         unsigned ret = 0;
 234         while (list) {
 235                 list = list->next;
 236                 ret++;
 237         }
 238         return ret;
 239 }
 240
 241 int object_list_contains(struct object_list *list, struct object *obj)
 242 {
 243         while (list) {
 244                 if (list->item == obj)
 245                         return 1;
 246                 list = list->next;
 247         }
 248         return 0;
 249 }