Revision f309e8e768ec5de97e8ab3dcd223f32865176290 authored by Junio C Hamano on 09 January 2018, 18:05:51 UTC, committed by Junio C Hamano on 09 January 2018, 18:39:30 UTC
When merging another branch into ours, if their tree is the same as the common ancestor's, we can declare that our tree represents the result of three-way merge. In such a case, the recursive merge backend incorrectly used to create a commit out of our index, even when the index has changes. A recent fix attempted to prevent this by adding a comparison between "our" tree and the index, but forgot that this check must be restricted only to the outermost merge. Inner merges performed by the recursive backend across merge bases are by definition made from scratch without having any local changes added to the index. The call to index_has_changes() during an inner merge is working on the index that has no relation to the merge being performed, preventing legitimate merges from getting carried out. Fix it by limiting the check to the outermost merge. Signed-off-by: Junio C Hamano <gitster@pobox.com>
1 parent 65170c0
object.c
#include "cache.h"
#include "object.h"
#include "blob.h"
#include "tree.h"
#include "commit.h"
#include "tag.h"
static struct object **obj_hash;
static int nr_objs, obj_hash_size;
unsigned int get_max_object_index(void)
{
return obj_hash_size;
}
struct object *get_indexed_object(unsigned int idx)
{
return obj_hash[idx];
}
static const char *object_type_strings[] = {
NULL, /* OBJ_NONE = 0 */
"commit", /* OBJ_COMMIT = 1 */
"tree", /* OBJ_TREE = 2 */
"blob", /* OBJ_BLOB = 3 */
"tag", /* OBJ_TAG = 4 */
};
const char *typename(unsigned int type)
{
if (type >= ARRAY_SIZE(object_type_strings))
return NULL;
return object_type_strings[type];
}
int type_from_string_gently(const char *str, ssize_t len, int gentle)
{
int i;
if (len < 0)
len = strlen(str);
for (i = 1; i < ARRAY_SIZE(object_type_strings); i++)
if (!strncmp(str, object_type_strings[i], len) &&
object_type_strings[i][len] == '\0')
return i;
if (gentle)
return -1;
die("invalid object type \"%s\"", str);
}
/*
* 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)
{
return sha1hash(sha1) & (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->oid.hash, size);
while (hash[j]) {
j++;
if (j >= size)
j = 0;
}
hash[j] = obj;
}
/*
* 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, first;
struct object *obj;
if (!obj_hash)
return NULL;
first = i = hash_obj(sha1, obj_hash_size);
while ((obj = obj_hash[i]) != NULL) {
if (!hashcmp(sha1, obj->oid.hash))
break;
i++;
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.
*/
SWAP(obj_hash[i], obj_hash[first]);
}
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;
new_hash = xcalloc(new_hash_size, sizeof(struct object *));
for (i = 0; i < obj_hash_size; i++) {
struct object *obj = obj_hash[i];
if (!obj)
continue;
insert_obj_hash(obj, new_hash, new_hash_size);
}
free(obj_hash);
obj_hash = new_hash;
obj_hash_size = new_hash_size;
}
void *create_object(const unsigned char *sha1, void *o)
{
struct object *obj = o;
obj->parsed = 0;
obj->flags = 0;
hashcpy(obj->oid.hash, sha1);
if (obj_hash_size - 1 <= nr_objs * 2)
grow_object_hash();
insert_obj_hash(obj, obj_hash, obj_hash_size);
nr_objs++;
return obj;
}
void *object_as_type(struct object *obj, enum object_type type, int quiet)
{
if (obj->type == type)
return obj;
else if (obj->type == OBJ_NONE) {
if (type == OBJ_COMMIT)
((struct commit *)obj)->index = alloc_commit_index();
obj->type = type;
return obj;
}
else {
if (!quiet)
error("object %s is a %s, not a %s",
oid_to_hex(&obj->oid),
typename(obj->type), typename(type));
return NULL;
}
}
struct object *lookup_unknown_object(const unsigned char *sha1)
{
struct object *obj = lookup_object(sha1);
if (!obj)
obj = create_object(sha1, alloc_object_node());
return obj;
}
struct object *parse_object_buffer(const struct object_id *oid, enum object_type type, unsigned long size, void *buffer, int *eaten_p)
{
struct object *obj;
*eaten_p = 0;
obj = NULL;
if (type == OBJ_BLOB) {
struct blob *blob = lookup_blob(oid);
if (blob) {
if (parse_blob_buffer(blob, buffer, size))
return NULL;
obj = &blob->object;
}
} else if (type == OBJ_TREE) {
struct tree *tree = lookup_tree(oid);
if (tree) {
obj = &tree->object;
if (!tree->buffer)
tree->object.parsed = 0;
if (!tree->object.parsed) {
if (parse_tree_buffer(tree, buffer, size))
return NULL;
*eaten_p = 1;
}
}
} else if (type == OBJ_COMMIT) {
struct commit *commit = lookup_commit(oid);
if (commit) {
if (parse_commit_buffer(commit, buffer, size))
return NULL;
if (!get_cached_commit_buffer(commit, NULL)) {
set_commit_buffer(commit, buffer, size);
*eaten_p = 1;
}
obj = &commit->object;
}
} else if (type == OBJ_TAG) {
struct tag *tag = lookup_tag(oid);
if (tag) {
if (parse_tag_buffer(tag, buffer, size))
return NULL;
obj = &tag->object;
}
} else {
warning("object %s has unknown type id %d", oid_to_hex(oid), type);
obj = NULL;
}
return obj;
}
struct object *parse_object_or_die(const struct object_id *oid,
const char *name)
{
struct object *o = parse_object(oid);
if (o)
return o;
die(_("unable to parse object: %s"), name ? name : oid_to_hex(oid));
}
struct object *parse_object(const struct object_id *oid)
{
unsigned long size;
enum object_type type;
int eaten;
const unsigned char *repl = lookup_replace_object(oid->hash);
void *buffer;
struct object *obj;
obj = lookup_object(oid->hash);
if (obj && obj->parsed)
return obj;
if ((obj && obj->type == OBJ_BLOB) ||
(!obj && has_object_file(oid) &&
sha1_object_info(oid->hash, NULL) == OBJ_BLOB)) {
if (check_sha1_signature(repl, NULL, 0, NULL) < 0) {
error("sha1 mismatch %s", oid_to_hex(oid));
return NULL;
}
parse_blob_buffer(lookup_blob(oid), NULL, 0);
return lookup_object(oid->hash);
}
buffer = read_sha1_file(oid->hash, &type, &size);
if (buffer) {
if (check_sha1_signature(repl, buffer, size, typename(type)) < 0) {
free(buffer);
error("sha1 mismatch %s", sha1_to_hex(repl));
return NULL;
}
obj = parse_object_buffer(oid, type, size, buffer, &eaten);
if (!eaten)
free(buffer);
return obj;
}
return NULL;
}
struct object_list *object_list_insert(struct object *item,
struct object_list **list_p)
{
struct object_list *new_list = xmalloc(sizeof(struct object_list));
new_list->item = item;
new_list->next = *list_p;
*list_p = new_list;
return new_list;
}
int object_list_contains(struct object_list *list, struct object *obj)
{
while (list) {
if (list->item == obj)
return 1;
list = list->next;
}
return 0;
}
/*
* 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_path(struct object *obj, const char *name,
struct object_array *array,
unsigned mode, const char *path)
{
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;
REALLOC_ARRAY(objects, alloc);
array->alloc = alloc;
array->objects = objects;
}
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;
if (path)
entry->path = xstrdup(path);
else
entry->path = NULL;
array->nr = ++nr;
}
void add_object_array(struct object *obj, const char *name, struct object_array *array)
{
add_object_array_with_path(obj, name, array, S_IFINVALID, NULL);
}
/*
* Free all memory associated with an entry; the result is
* in an unspecified state and should not be examined.
*/
static void object_array_release_entry(struct object_array_entry *ent)
{
if (ent->name != object_array_slopbuf)
free(ent->name);
free(ent->path);
}
struct object *object_array_pop(struct object_array *array)
{
struct object *ret;
if (!array->nr)
return NULL;
ret = array->objects[array->nr - 1].item;
object_array_release_entry(&array->objects[array->nr - 1]);
array->nr--;
return ret;
}
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 (src = dst = 0; src < nr; src++) {
if (want(&objects[src], cb_data)) {
if (src != dst)
objects[dst] = objects[src];
dst++;
} else {
object_array_release_entry(&objects[src]);
}
}
array->nr = dst;
}
void object_array_clear(struct object_array *array)
{
int i;
for (i = 0; i < array->nr; i++)
object_array_release_entry(&array->objects[i]);
FREE_AND_NULL(array->objects);
array->nr = array->alloc = 0;
}
/*
* 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 {
object_array_release_entry(&objects[src]);
}
}
}
void clear_object_flags(unsigned flags)
{
int i;
for (i=0; i < obj_hash_size; i++) {
struct object *obj = obj_hash[i];
if (obj)
obj->flags &= ~flags;
}
}
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