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![Jeff King](/assets/img/avatar_default.png)
Many call-sites of parse_object assume that they will get a non-NULL return value; this is not the case if we encounter an error while parsing the object. This patch adds a wrapper function around parse_object that handles dying automatically, and uses it anywhere we immediately try to access the return value as a non-NULL pointer (i.e., anywhere that we would currently segfault). This wrapper may also be useful in other places. The most obvious one is code like: o = parse_object(sha1); if (!o) die(...); However, these should not be mechanically converted to parse_object_or_die, as the die message is sometimes customized. Later patches can address these sites on a case-by-case basis. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
310 lines
6.6 KiB
C
310 lines
6.6 KiB
C
#include "cache.h"
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#include "object.h"
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#include "blob.h"
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#include "tree.h"
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#include "commit.h"
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#include "tag.h"
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static struct object **obj_hash;
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static int nr_objs, obj_hash_size;
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unsigned int get_max_object_index(void)
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{
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return obj_hash_size;
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}
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struct object *get_indexed_object(unsigned int idx)
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{
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return obj_hash[idx];
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}
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static const char *object_type_strings[] = {
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NULL, /* OBJ_NONE = 0 */
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"commit", /* OBJ_COMMIT = 1 */
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"tree", /* OBJ_TREE = 2 */
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"blob", /* OBJ_BLOB = 3 */
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"tag", /* OBJ_TAG = 4 */
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};
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const char *typename(unsigned int type)
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{
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if (type >= ARRAY_SIZE(object_type_strings))
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return NULL;
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return object_type_strings[type];
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}
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int type_from_string(const char *str)
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{
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int i;
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for (i = 1; i < ARRAY_SIZE(object_type_strings); i++)
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if (!strcmp(str, object_type_strings[i]))
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return i;
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die("invalid object type \"%s\"", str);
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}
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static unsigned int hash_obj(struct object *obj, unsigned int n)
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{
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unsigned int hash;
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memcpy(&hash, obj->sha1, sizeof(unsigned int));
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return hash % n;
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}
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static void insert_obj_hash(struct object *obj, struct object **hash, unsigned int size)
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{
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unsigned int j = hash_obj(obj, size);
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while (hash[j]) {
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j++;
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if (j >= size)
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j = 0;
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}
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hash[j] = obj;
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}
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static unsigned int hashtable_index(const unsigned char *sha1)
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{
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unsigned int i;
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memcpy(&i, sha1, sizeof(unsigned int));
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return i % obj_hash_size;
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}
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struct object *lookup_object(const unsigned char *sha1)
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{
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unsigned int i;
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struct object *obj;
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if (!obj_hash)
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return NULL;
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i = hashtable_index(sha1);
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while ((obj = obj_hash[i]) != NULL) {
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if (!hashcmp(sha1, obj->sha1))
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break;
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i++;
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if (i == obj_hash_size)
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i = 0;
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}
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return obj;
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}
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static void grow_object_hash(void)
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{
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int i;
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int new_hash_size = obj_hash_size < 32 ? 32 : 2 * obj_hash_size;
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struct object **new_hash;
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new_hash = xcalloc(new_hash_size, sizeof(struct object *));
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for (i = 0; i < obj_hash_size; i++) {
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struct object *obj = obj_hash[i];
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if (!obj)
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continue;
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insert_obj_hash(obj, new_hash, new_hash_size);
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}
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free(obj_hash);
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obj_hash = new_hash;
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obj_hash_size = new_hash_size;
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}
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void *create_object(const unsigned char *sha1, int type, void *o)
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{
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struct object *obj = o;
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obj->parsed = 0;
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obj->used = 0;
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obj->type = type;
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obj->flags = 0;
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hashcpy(obj->sha1, sha1);
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if (obj_hash_size - 1 <= nr_objs * 2)
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grow_object_hash();
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insert_obj_hash(obj, obj_hash, obj_hash_size);
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nr_objs++;
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return obj;
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}
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struct object *lookup_unknown_object(const unsigned char *sha1)
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{
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struct object *obj = lookup_object(sha1);
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if (!obj)
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obj = create_object(sha1, OBJ_NONE, alloc_object_node());
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return obj;
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}
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struct object *parse_object_buffer(const unsigned char *sha1, enum object_type type, unsigned long size, void *buffer, int *eaten_p)
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{
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struct object *obj;
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int eaten = 0;
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obj = NULL;
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if (type == OBJ_BLOB) {
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struct blob *blob = lookup_blob(sha1);
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if (blob) {
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if (parse_blob_buffer(blob, buffer, size))
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return NULL;
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obj = &blob->object;
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}
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} else if (type == OBJ_TREE) {
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struct tree *tree = lookup_tree(sha1);
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if (tree) {
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obj = &tree->object;
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if (!tree->buffer)
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tree->object.parsed = 0;
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if (!tree->object.parsed) {
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if (parse_tree_buffer(tree, buffer, size))
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return NULL;
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eaten = 1;
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}
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}
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} else if (type == OBJ_COMMIT) {
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struct commit *commit = lookup_commit(sha1);
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if (commit) {
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if (parse_commit_buffer(commit, buffer, size))
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return NULL;
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if (!commit->buffer) {
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commit->buffer = buffer;
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eaten = 1;
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}
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obj = &commit->object;
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}
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} else if (type == OBJ_TAG) {
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struct tag *tag = lookup_tag(sha1);
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if (tag) {
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if (parse_tag_buffer(tag, buffer, size))
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return NULL;
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obj = &tag->object;
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}
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} else {
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warning("object %s has unknown type id %d", sha1_to_hex(sha1), type);
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obj = NULL;
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}
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if (obj && obj->type == OBJ_NONE)
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obj->type = type;
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*eaten_p = eaten;
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return obj;
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}
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struct object *parse_object_or_die(const unsigned char *sha1,
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const char *name)
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{
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struct object *o = parse_object(sha1);
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if (o)
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return o;
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die(_("unable to parse object: %s"), name ? name : sha1_to_hex(sha1));
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}
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struct object *parse_object(const unsigned char *sha1)
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{
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unsigned long size;
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enum object_type type;
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int eaten;
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const unsigned char *repl = lookup_replace_object(sha1);
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void *buffer;
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struct object *obj;
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obj = lookup_object(sha1);
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if (obj && obj->parsed)
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return obj;
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if ((obj && obj->type == OBJ_BLOB) ||
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(!obj && has_sha1_file(sha1) &&
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sha1_object_info(sha1, NULL) == OBJ_BLOB)) {
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if (check_sha1_signature(repl, NULL, 0, NULL) < 0) {
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error("sha1 mismatch %s", sha1_to_hex(repl));
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return NULL;
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}
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parse_blob_buffer(lookup_blob(sha1), NULL, 0);
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return lookup_object(sha1);
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}
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buffer = read_sha1_file(sha1, &type, &size);
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if (buffer) {
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if (check_sha1_signature(repl, buffer, size, typename(type)) < 0) {
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free(buffer);
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error("sha1 mismatch %s", sha1_to_hex(repl));
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return NULL;
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}
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obj = parse_object_buffer(sha1, type, size, buffer, &eaten);
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if (!eaten)
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free(buffer);
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return obj;
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}
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return NULL;
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}
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struct object_list *object_list_insert(struct object *item,
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struct object_list **list_p)
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{
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struct object_list *new_list = xmalloc(sizeof(struct object_list));
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new_list->item = item;
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new_list->next = *list_p;
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*list_p = new_list;
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return new_list;
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}
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int object_list_contains(struct object_list *list, struct object *obj)
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{
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while (list) {
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if (list->item == obj)
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return 1;
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list = list->next;
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}
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return 0;
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}
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void add_object_array(struct object *obj, const char *name, struct object_array *array)
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{
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add_object_array_with_mode(obj, name, array, S_IFINVALID);
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}
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void add_object_array_with_mode(struct object *obj, const char *name, struct object_array *array, unsigned mode)
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{
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unsigned nr = array->nr;
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unsigned alloc = array->alloc;
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struct object_array_entry *objects = array->objects;
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if (nr >= alloc) {
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alloc = (alloc + 32) * 2;
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objects = xrealloc(objects, alloc * sizeof(*objects));
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array->alloc = alloc;
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array->objects = objects;
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}
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objects[nr].item = obj;
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objects[nr].name = name;
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objects[nr].mode = mode;
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array->nr = ++nr;
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}
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void object_array_remove_duplicates(struct object_array *array)
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{
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unsigned int ref, src, dst;
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struct object_array_entry *objects = array->objects;
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for (ref = 0; ref + 1 < array->nr; ref++) {
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for (src = ref + 1, dst = src;
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src < array->nr;
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src++) {
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if (!strcmp(objects[ref].name, objects[src].name))
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continue;
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if (src != dst)
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objects[dst] = objects[src];
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dst++;
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}
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array->nr = dst;
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}
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}
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void clear_object_flags(unsigned flags)
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{
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int i;
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for (i=0; i < obj_hash_size; i++) {
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struct object *obj = obj_hash[i];
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if (obj)
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obj->flags &= ~flags;
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}
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}
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