Example #1
0
File: notes.c Project: sanj/git
/*
 * To remove a leaf_node:
 * Search to the tree location appropriate for the given leaf_node's key:
 * - If location does not hold a matching entry, abort and do nothing.
 * - Replace the matching leaf_node with a NULL entry (and free the leaf_node).
 * - Consolidate int_nodes repeatedly, while walking up the tree towards root.
 */
static void note_tree_remove(struct notes_tree *t, struct int_node *tree,
		unsigned char n, struct leaf_node *entry)
{
	struct leaf_node *l;
	struct int_node *parent_stack[20];
	unsigned char i, j;
	void **p = note_tree_search(t, &tree, &n, entry->key_sha1);

	assert(GET_PTR_TYPE(entry) == 0); /* no type bits set */
	if (GET_PTR_TYPE(*p) != PTR_TYPE_NOTE)
		return; /* type mismatch, nothing to remove */
	l = (struct leaf_node *) CLR_PTR_TYPE(*p);
	if (hashcmp(l->key_sha1, entry->key_sha1))
		return; /* key mismatch, nothing to remove */

	/* we have found a matching entry */
	free(l);
	*p = SET_PTR_TYPE(NULL, PTR_TYPE_NULL);

	/* consolidate this tree level, and parent levels, if possible */
	if (!n)
		return; /* cannot consolidate top level */
	/* first, build stack of ancestors between root and current node */
	parent_stack[0] = t->root;
	for (i = 0; i < n; i++) {
		j = GET_NIBBLE(i, entry->key_sha1);
		parent_stack[i + 1] = CLR_PTR_TYPE(parent_stack[i]->a[j]);
	}
	assert(i == n && parent_stack[i] == tree);
	/* next, unwind stack until note_tree_consolidate() is done */
	while (i > 0 &&
	       !note_tree_consolidate(parent_stack[i], parent_stack[i - 1],
				      GET_NIBBLE(i - 1, entry->key_sha1)))
		i--;
}
Example #2
0
File: notes.c Project: Noffica/git
/*
 * To find a leaf_node:
 * Search to the tree location appropriate for the given key:
 * If a note entry with matching key, return the note entry, else return NULL.
 */
static struct leaf_node *note_tree_find(struct notes_tree *t,
		struct int_node *tree, unsigned char n,
		const unsigned char *key_sha1)
{
	void **p = note_tree_search(t, &tree, &n, key_sha1);
	if (GET_PTR_TYPE(*p) == PTR_TYPE_NOTE) {
		struct leaf_node *l = (struct leaf_node *) CLR_PTR_TYPE(*p);
		if (hasheq(key_sha1, l->key_oid.hash))
			return l;
	}
	return NULL;
}
Example #3
0
File: notes.c Project: Noffica/git
/*
 * To insert a leaf_node:
 * Search to the tree location appropriate for the given leaf_node's key:
 * - If location is unused (NULL), store the tweaked pointer directly there
 * - If location holds a note entry that matches the note-to-be-inserted, then
 *   combine the two notes (by calling the given combine_notes function).
 * - If location holds a note entry that matches the subtree-to-be-inserted,
 *   then unpack the subtree-to-be-inserted into the location.
 * - If location holds a matching subtree entry, unpack the subtree at that
 *   location, and restart the insert operation from that level.
 * - Else, create a new int_node, holding both the node-at-location and the
 *   node-to-be-inserted, and store the new int_node into the location.
 */
static int note_tree_insert(struct notes_tree *t, struct int_node *tree,
		unsigned char n, struct leaf_node *entry, unsigned char type,
		combine_notes_fn combine_notes)
{
	struct int_node *new_node;
	struct leaf_node *l;
	void **p = note_tree_search(t, &tree, &n, entry->key_oid.hash);
	int ret = 0;

	assert(GET_PTR_TYPE(entry) == 0); /* no type bits set */
	l = (struct leaf_node *) CLR_PTR_TYPE(*p);
	switch (GET_PTR_TYPE(*p)) {
	case PTR_TYPE_NULL:
		assert(!*p);
		if (is_null_oid(&entry->val_oid))
			free(entry);
		else
			*p = SET_PTR_TYPE(entry, type);
		return 0;
	case PTR_TYPE_NOTE:
		switch (type) {
		case PTR_TYPE_NOTE:
			if (oideq(&l->key_oid, &entry->key_oid)) {
				/* skip concatenation if l == entry */
				if (oideq(&l->val_oid, &entry->val_oid))
					return 0;

				ret = combine_notes(&l->val_oid,
						    &entry->val_oid);
				if (!ret && is_null_oid(&l->val_oid))
					note_tree_remove(t, tree, n, entry);
				free(entry);
				return ret;
			}
			break;
		case PTR_TYPE_SUBTREE:
			if (!SUBTREE_SHA1_PREFIXCMP(l->key_oid.hash,
						    entry->key_oid.hash)) {
				/* unpack 'entry' */
				load_subtree(t, entry, tree, n);
				free(entry);
				return 0;
			}
			break;
		}
		break;
	case PTR_TYPE_SUBTREE:
		if (!SUBTREE_SHA1_PREFIXCMP(entry->key_oid.hash, l->key_oid.hash)) {
			/* unpack 'l' and restart insert */
			*p = NULL;
			load_subtree(t, l, tree, n);
			free(l);
			return note_tree_insert(t, tree, n, entry, type,
						combine_notes);
		}
		break;
	}

	/* non-matching leaf_node */
	assert(GET_PTR_TYPE(*p) == PTR_TYPE_NOTE ||
	       GET_PTR_TYPE(*p) == PTR_TYPE_SUBTREE);
	if (is_null_oid(&entry->val_oid)) { /* skip insertion of empty note */
		free(entry);
		return 0;
	}
	new_node = (struct int_node *) xcalloc(1, sizeof(struct int_node));
	ret = note_tree_insert(t, new_node, n + 1, l, GET_PTR_TYPE(*p),
			       combine_notes);
	if (ret)
		return ret;
	*p = SET_PTR_TYPE(new_node, PTR_TYPE_INTERNAL);
	return note_tree_insert(t, new_node, n + 1, entry, type, combine_notes);
}
Example #4
0
File: notes.c Project: sanj/git
/*
 * To insert a leaf_node:
 * Search to the tree location appropriate for the given leaf_node's key:
 * - If location is unused (NULL), store the tweaked pointer directly there
 * - If location holds a note entry that matches the note-to-be-inserted, then
 *   combine the two notes (by calling the given combine_notes function).
 * - If location holds a note entry that matches the subtree-to-be-inserted,
 *   then unpack the subtree-to-be-inserted into the location.
 * - If location holds a matching subtree entry, unpack the subtree at that
 *   location, and restart the insert operation from that level.
 * - Else, create a new int_node, holding both the node-at-location and the
 *   node-to-be-inserted, and store the new int_node into the location.
 */
static void note_tree_insert(struct notes_tree *t, struct int_node *tree,
		unsigned char n, struct leaf_node *entry, unsigned char type,
		combine_notes_fn combine_notes)
{
	struct int_node *new_node;
	struct leaf_node *l;
	void **p = note_tree_search(t, &tree, &n, entry->key_sha1);

	assert(GET_PTR_TYPE(entry) == 0); /* no type bits set */
	l = (struct leaf_node *) CLR_PTR_TYPE(*p);
	switch (GET_PTR_TYPE(*p)) {
	case PTR_TYPE_NULL:
		assert(!*p);
		*p = SET_PTR_TYPE(entry, type);
		return;
	case PTR_TYPE_NOTE:
		switch (type) {
		case PTR_TYPE_NOTE:
			if (!hashcmp(l->key_sha1, entry->key_sha1)) {
				/* skip concatenation if l == entry */
				if (!hashcmp(l->val_sha1, entry->val_sha1))
					return;

				if (combine_notes(l->val_sha1, entry->val_sha1))
					die("failed to combine notes %s and %s"
					    " for object %s",
					    sha1_to_hex(l->val_sha1),
					    sha1_to_hex(entry->val_sha1),
					    sha1_to_hex(l->key_sha1));
				free(entry);
				return;
			}
			break;
		case PTR_TYPE_SUBTREE:
			if (!SUBTREE_SHA1_PREFIXCMP(l->key_sha1,
						    entry->key_sha1)) {
				/* unpack 'entry' */
				load_subtree(t, entry, tree, n);
				free(entry);
				return;
			}
			break;
		}
		break;
	case PTR_TYPE_SUBTREE:
		if (!SUBTREE_SHA1_PREFIXCMP(entry->key_sha1, l->key_sha1)) {
			/* unpack 'l' and restart insert */
			*p = NULL;
			load_subtree(t, l, tree, n);
			free(l);
			note_tree_insert(t, tree, n, entry, type,
					 combine_notes);
			return;
		}
		break;
	}

	/* non-matching leaf_node */
	assert(GET_PTR_TYPE(*p) == PTR_TYPE_NOTE ||
	       GET_PTR_TYPE(*p) == PTR_TYPE_SUBTREE);
	new_node = (struct int_node *) xcalloc(sizeof(struct int_node), 1);
	note_tree_insert(t, new_node, n + 1, l, GET_PTR_TYPE(*p),
			 combine_notes);
	*p = SET_PTR_TYPE(new_node, PTR_TYPE_INTERNAL);
	note_tree_insert(t, new_node, n + 1, entry, type, combine_notes);
}