On Wed, 2010-09-15 at 18:53 +0200, martin f krafft wrote:
> also sprach David Lutterkort <lut...@redhat.com> [2010.09.15.1756 +0200]:
> > To catch your use case in all generality, I could just write the
> > changed file to a memstream, do the compare from that, and only
> > write to .augnew when something has changed.
>
> Except that will break for large files (however unlikely that ma
> be).
Attached is a simple patch that I just committed upstream so that doing
a 'set /foo bar' will not cause any file I/O when /foo already has the
value bar.
For the bigger issue of writing to memory first, and then to .augnew, I
am still on the fence of whether that is a good idea (and isn't so great
for large files, though there are other things in Augeas which will
consume considerable amounts of memory on large files)
David
>From 3ef65496495d228751a0898299c2398b7de9baf4 Mon Sep 17 00:00:00 2001
From: David Lutterkort <lut...@redhat.com>
Date: Wed, 15 Sep 2010 16:39:08 -0700
Subject: [PATCH] When setting a tree node to the value it already has, do not modify the tree
---
src/augeas.c | 7 +++++++
tests/test-save.c | 2 +-
2 files changed, 8 insertions(+), 1 deletions(-)
diff --git a/src/augeas.c b/src/augeas.c
index d2ef353..25ca016 100644
--- a/src/augeas.c
+++ b/src/augeas.c
@@ -157,6 +157,11 @@ struct tree *tree_find_cr(struct augeas *aug, const char *path) {
}
void tree_store_value(struct tree *tree, char **value) {
+ if (streqv(tree->value, *value)) {
+ free(*value);
+ *value = NULL;
+ return;
+ }
if (tree->value != NULL) {
free(tree->value);
tree->value = NULL;
@@ -171,6 +176,8 @@ void tree_store_value(struct tree *tree, char **value) {
int tree_set_value(struct tree *tree, const char *value) {
char *v = NULL;
+ if (streqv(tree->value, value))
+ return 0;
if (value != NULL) {
v = strdup(value);
if (v == NULL)
diff --git a/tests/test-save.c b/tests/test-save.c
index 673a5a1..68b7736 100644
--- a/tests/test-save.c
+++ b/tests/test-save.c
@@ -112,7 +112,7 @@ static void testMultipleXfm(CuTest *tc) {
r = aug_set(aug, "/augeas/load/Yum2/incl", "/etc/yum.repos.d/*");
CuAssertIntEquals(tc, 0, r);
- r = aug_set(aug, "/files/etc/yum.repos.d/fedora.repo/fedora/enabled", "1");
+ r = aug_set(aug, "/files/etc/yum.repos.d/fedora.repo/fedora/enabled", "0");
CuAssertIntEquals(tc, 0, r);
r = aug_save(aug);
--
1.7.2.3
