path: root/userdiff.c
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authorJeff King <>2010-04-02 00:12:15 (GMT)
committerJunio C Hamano <>2010-04-02 07:05:31 (GMT)
commitd9bae1a178f0f8b198ea611e874975214ad6f990 (patch)
tree33918127aca49cf9c33f9d83371e4725641f5333 /userdiff.c
parent840383b2c2bd7179604f5c2595bf95e22a4e0c84 (diff)
diff: cache textconv output
Running a textconv filter can take a long time. It's particularly bad for a large file which needs to be spooled to disk, but even for small files, the fork+exec overhead can add up for something like "git log -p". This patch uses the notes-cache mechanism to keep a fast cache of textconv output. Caches are stored in refs/notes/textconv/$x, where $x is the userdiff driver defined in gitattributes. Caching is enabled only if diff.$x.cachetextconv is true. In my test repo, on a commit with 45 jpg and avi files changed and a textconv to show their exif tags: [before] $ time git show >/dev/null real 0m13.724s user 0m12.057s sys 0m1.624s [after, first run] $ git config diff.mfo.cachetextconv true $ time git show >/dev/null real 0m14.252s user 0m12.197s sys 0m1.800s [after, subsequent runs] $ time git show >/dev/null real 0m0.352s user 0m0.148s sys 0m0.200s So for a slight (3.8%) cost on the first run, we achieve an almost 40x speed up on subsequent runs. Signed-off-by: Jeff King <> Signed-off-by: Junio C Hamano <>
Diffstat (limited to 'userdiff.c')
1 files changed, 9 insertions, 0 deletions
diff --git a/userdiff.c b/userdiff.c
index df99249..67003fb 100644
--- a/userdiff.c
+++ b/userdiff.c
@@ -1,3 +1,4 @@
+#include "cache.h"
#include "userdiff.h"
#include "cache.h"
#include "attr.h"
@@ -167,6 +168,12 @@ static int parse_tristate(int *b, const char *k, const char *v)
return 1;
+static int parse_bool(int *b, const char *k, const char *v)
+ *b = git_config_bool(k, v);
+ return 1;
int userdiff_config(const char *k, const char *v)
struct userdiff_driver *drv;
@@ -181,6 +188,8 @@ int userdiff_config(const char *k, const char *v)
return parse_string(&drv->external, k, v);
if ((drv = parse_driver(k, v, "textconv")))
return parse_string(&drv->textconv, k, v);
+ if ((drv = parse_driver(k, v, "cachetextconv")))
+ return parse_bool(&drv->textconv_want_cache, k, v);
if ((drv = parse_driver(k, v, "wordregex")))
return parse_string(&drv->word_regex, k, v);