git/reftable/tree.c
Han-Wen Nienhuys 35425d1034 reftable: a generic binary tree implementation
The reftable format includes support for an (OID => ref) map. This map can speed
up visibility and reachability checks. In particular, various operations along
the fetch/push path within Gerrit have ben sped up by using this structure.

The map is constructed with help of a binary tree. Object IDs are hashes, so
they are uniformly distributed. Hence, the tree does not attempt forced
rebalancing.

Signed-off-by: Han-Wen Nienhuys <hanwen@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-10-08 10:45:48 -07:00

64 lines
1.2 KiB
C

/*
Copyright 2020 Google LLC
Use of this source code is governed by a BSD-style
license that can be found in the LICENSE file or at
https://developers.google.com/open-source/licenses/bsd
*/
#include "tree.h"
#include "basics.h"
#include "system.h"
struct tree_node *tree_search(void *key, struct tree_node **rootp,
int (*compare)(const void *, const void *),
int insert)
{
int res;
if (*rootp == NULL) {
if (!insert) {
return NULL;
} else {
struct tree_node *n =
reftable_calloc(sizeof(struct tree_node));
n->key = key;
*rootp = n;
return *rootp;
}
}
res = compare(key, (*rootp)->key);
if (res < 0)
return tree_search(key, &(*rootp)->left, compare, insert);
else if (res > 0)
return tree_search(key, &(*rootp)->right, compare, insert);
return *rootp;
}
void infix_walk(struct tree_node *t, void (*action)(void *arg, void *key),
void *arg)
{
if (t->left) {
infix_walk(t->left, action, arg);
}
action(arg, t->key);
if (t->right) {
infix_walk(t->right, action, arg);
}
}
void tree_free(struct tree_node *t)
{
if (t == NULL) {
return;
}
if (t->left) {
tree_free(t->left);
}
if (t->right) {
tree_free(t->right);
}
reftable_free(t);
}