diff options
Diffstat (limited to 'object.c')
| -rw-r--r-- | object.c | 175 |
1 files changed, 141 insertions, 34 deletions
@@ -43,16 +43,35 @@ int type_from_string(const char *str) die("invalid object type \"%s\"", str); } -static unsigned int hash_obj(struct object *obj, unsigned int n) +/* + * Return a numerical hash value between 0 and n-1 for the object with + * the specified sha1. n must be a power of 2. Please note that the + * return value is *not* consistent across computer architectures. + */ +static unsigned int hash_obj(const unsigned char *sha1, unsigned int n) { unsigned int hash; - memcpy(&hash, obj->sha1, sizeof(unsigned int)); - return hash % n; + + /* + * Since the sha1 is essentially random, we just take the + * required number of bits directly from the first + * sizeof(unsigned int) bytes of sha1. First we have to copy + * the bytes into a properly aligned integer. If we cared + * about getting consistent results across architectures, we + * would have to call ntohl() here, too. + */ + memcpy(&hash, sha1, sizeof(unsigned int)); + return hash & (n - 1); } +/* + * Insert obj into the hash table hash, which has length size (which + * must be a power of 2). On collisions, simply overflow to the next + * empty bucket. + */ static void insert_obj_hash(struct object *obj, struct object **hash, unsigned int size) { - unsigned int j = hash_obj(obj, size); + unsigned int j = hash_obj(obj->sha1, size); while (hash[j]) { j++; @@ -62,22 +81,19 @@ static void insert_obj_hash(struct object *obj, struct object **hash, unsigned i hash[j] = obj; } -static unsigned int hashtable_index(const unsigned char *sha1) -{ - unsigned int i; - memcpy(&i, sha1, sizeof(unsigned int)); - return i % obj_hash_size; -} - +/* + * Look up the record for the given sha1 in the hash map stored in + * obj_hash. Return NULL if it was not found. + */ struct object *lookup_object(const unsigned char *sha1) { - unsigned int i; + unsigned int i, first; struct object *obj; if (!obj_hash) return NULL; - i = hashtable_index(sha1); + first = i = hash_obj(sha1, obj_hash_size); while ((obj = obj_hash[i]) != NULL) { if (!hashcmp(sha1, obj->sha1)) break; @@ -85,12 +101,31 @@ struct object *lookup_object(const unsigned char *sha1) if (i == obj_hash_size) i = 0; } + if (obj && i != first) { + /* + * Move object to where we started to look for it so + * that we do not need to walk the hash table the next + * time we look for it. + */ + struct object *tmp = obj_hash[i]; + obj_hash[i] = obj_hash[first]; + obj_hash[first] = tmp; + } return obj; } +/* + * Increase the size of the hash map stored in obj_hash to the next + * power of 2 (but at least 32). Copy the existing values to the new + * hash map. + */ static void grow_object_hash(void) { int i; + /* + * Note that this size must always be power-of-2 to match hash_obj + * above. + */ int new_hash_size = obj_hash_size < 32 ? 32 : 2 * obj_hash_size; struct object **new_hash; @@ -135,7 +170,7 @@ struct object *lookup_unknown_object(const unsigned char *sha1) struct object *parse_object_buffer(const unsigned char *sha1, enum object_type type, unsigned long size, void *buffer, int *eaten_p) { struct object *obj; - int eaten = 0; + *eaten_p = 0; obj = NULL; if (type == OBJ_BLOB) { @@ -154,7 +189,7 @@ struct object *parse_object_buffer(const unsigned char *sha1, enum object_type t if (!tree->object.parsed) { if (parse_tree_buffer(tree, buffer, size)) return NULL; - eaten = 1; + *eaten_p = 1; } } } else if (type == OBJ_COMMIT) { @@ -164,7 +199,7 @@ struct object *parse_object_buffer(const unsigned char *sha1, enum object_type t return NULL; if (!commit->buffer) { commit->buffer = buffer; - eaten = 1; + *eaten_p = 1; } obj = &commit->object; } @@ -181,10 +216,19 @@ struct object *parse_object_buffer(const unsigned char *sha1, enum object_type t } if (obj && obj->type == OBJ_NONE) obj->type = type; - *eaten_p = eaten; return obj; } +struct object *parse_object_or_die(const unsigned char *sha1, + const char *name) +{ + struct object *o = parse_object(sha1); + if (o) + return o; + + die(_("unable to parse object: %s"), name ? name : sha1_to_hex(sha1)); +} + struct object *parse_object(const unsigned char *sha1) { unsigned long size; @@ -245,16 +289,21 @@ int object_list_contains(struct object_list *list, struct object *obj) return 0; } -void add_object_array(struct object *obj, const char *name, struct object_array *array) -{ - add_object_array_with_mode(obj, name, array, S_IFINVALID); -} +/* + * A zero-length string to which object_array_entry::name can be + * initialized without requiring a malloc/free. + */ +static char object_array_slopbuf[1]; -void add_object_array_with_mode(struct object *obj, const char *name, struct object_array *array, unsigned mode) +static void add_object_array_with_mode_context(struct object *obj, const char *name, + struct object_array *array, + unsigned mode, + struct object_context *context) { unsigned nr = array->nr; unsigned alloc = array->alloc; struct object_array_entry *objects = array->objects; + struct object_array_entry *entry; if (nr >= alloc) { alloc = (alloc + 32) * 2; @@ -262,28 +311,86 @@ void add_object_array_with_mode(struct object *obj, const char *name, struct obj array->alloc = alloc; array->objects = objects; } - objects[nr].item = obj; - objects[nr].name = name; - objects[nr].mode = mode; + entry = &objects[nr]; + entry->item = obj; + if (!name) + entry->name = NULL; + else if (!*name) + /* Use our own empty string instead of allocating one: */ + entry->name = object_array_slopbuf; + else + entry->name = xstrdup(name); + entry->mode = mode; + entry->context = context; array->nr = ++nr; } -void object_array_remove_duplicates(struct object_array *array) +void add_object_array(struct object *obj, const char *name, struct object_array *array) +{ + add_object_array_with_mode(obj, name, array, S_IFINVALID); +} + +void add_object_array_with_mode(struct object *obj, const char *name, struct object_array *array, unsigned mode) { - unsigned int ref, src, dst; + add_object_array_with_mode_context(obj, name, array, mode, NULL); +} + +void add_object_array_with_context(struct object *obj, const char *name, struct object_array *array, struct object_context *context) +{ + if (context) + add_object_array_with_mode_context(obj, name, array, context->mode, context); + else + add_object_array_with_mode_context(obj, name, array, S_IFINVALID, context); +} + +void object_array_filter(struct object_array *array, + object_array_each_func_t want, void *cb_data) +{ + unsigned nr = array->nr, src, dst; struct object_array_entry *objects = array->objects; - for (ref = 0; ref + 1 < array->nr; ref++) { - for (src = ref + 1, dst = src; - src < array->nr; - src++) { - if (!strcmp(objects[ref].name, objects[src].name)) - continue; + for (src = dst = 0; src < nr; src++) { + if (want(&objects[src], cb_data)) { if (src != dst) objects[dst] = objects[src]; dst++; + } else { + if (objects[src].name != object_array_slopbuf) + free(objects[src].name); + } + } + array->nr = dst; +} + +/* + * Return true iff array already contains an entry with name. + */ +static int contains_name(struct object_array *array, const char *name) +{ + unsigned nr = array->nr, i; + struct object_array_entry *object = array->objects; + + for (i = 0; i < nr; i++, object++) + if (!strcmp(object->name, name)) + return 1; + return 0; +} + +void object_array_remove_duplicates(struct object_array *array) +{ + unsigned nr = array->nr, src; + struct object_array_entry *objects = array->objects; + + array->nr = 0; + for (src = 0; src < nr; src++) { + if (!contains_name(array, objects[src].name)) { + if (src != array->nr) + objects[array->nr] = objects[src]; + array->nr++; + } else { + if (objects[src].name != object_array_slopbuf) + free(objects[src].name); } - array->nr = dst; } } |