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authorJunio C Hamano <gitster@pobox.com>2009-01-19 22:18:29 -0800
committerJunio C Hamano <gitster@pobox.com>2009-01-19 22:18:29 -0800
commit101d15e09712a0183db99d228d975c62970654cf (patch)
tree794021ad7ade07c4835ec9c356930c637da26df7
parent39765e5941d36f74cec4764d315da0ba5743547c (diff)
downloadgit-101d15e09712a0183db99d228d975c62970654cf.tar.gz
git-101d15e09712a0183db99d228d975c62970654cf.tar.xz
Introduce for_each_recent_reflog_ent().
This can be used to scan only the last few kilobytes of a reflog, as a cheap optimization when the data you are looking for is likely to be found near the end of it. The caller is expected to fall back to the full scan if that is not the case. Signed-off-by: Junio C Hamano <gitster@pobox.com>
-rw-r--r--refs.c17
-rw-r--r--refs.h1
-rw-r--r--sha1_name.c8
3 files changed, 24 insertions, 2 deletions
diff --git a/refs.c b/refs.c
index 33ced65a7..024211d72 100644
--- a/refs.c
+++ b/refs.c
@@ -1453,7 +1453,7 @@ int read_ref_at(const char *ref, unsigned long at_time, int cnt, unsigned char *
return 1;
}
-int for_each_reflog_ent(const char *ref, each_reflog_ent_fn fn, void *cb_data)
+int for_each_recent_reflog_ent(const char *ref, each_reflog_ent_fn fn, long ofs, void *cb_data)
{
const char *logfile;
FILE *logfp;
@@ -1464,6 +1464,16 @@ int for_each_reflog_ent(const char *ref, each_reflog_ent_fn fn, void *cb_data)
logfp = fopen(logfile, "r");
if (!logfp)
return -1;
+
+ if (ofs) {
+ struct stat statbuf;
+ if (fstat(fileno(logfp), &statbuf) ||
+ statbuf.st_size < ofs ||
+ fseek(logfp, -ofs, SEEK_END) ||
+ fgets(buf, sizeof(buf), logfp))
+ return -1;
+ }
+
while (fgets(buf, sizeof(buf), logfp)) {
unsigned char osha1[20], nsha1[20];
char *email_end, *message;
@@ -1497,6 +1507,11 @@ int for_each_reflog_ent(const char *ref, each_reflog_ent_fn fn, void *cb_data)
return ret;
}
+int for_each_reflog_ent(const char *ref, each_reflog_ent_fn fn, void *cb_data)
+{
+ return for_each_recent_reflog_ent(ref, fn, 0, cb_data);
+}
+
static int do_for_each_reflog(const char *base, each_ref_fn fn, void *cb_data)
{
DIR *dir = opendir(git_path("logs/%s", base));
diff --git a/refs.h b/refs.h
index 06ad26055..3bb529d38 100644
--- a/refs.h
+++ b/refs.h
@@ -60,6 +60,7 @@ extern int read_ref_at(const char *ref, unsigned long at_time, int cnt, unsigned
/* iterate over reflog entries */
typedef int each_reflog_ent_fn(unsigned char *osha1, unsigned char *nsha1, const char *, unsigned long, int, const char *, void *);
int for_each_reflog_ent(const char *ref, each_reflog_ent_fn fn, void *cb_data);
+int for_each_recent_reflog_ent(const char *ref, each_reflog_ent_fn fn, long, void *cb_data);
/*
* Calls the specified function for each reflog file until it returns nonzero,
diff --git a/sha1_name.c b/sha1_name.c
index 4c0370bb7..38c9f1b19 100644
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -775,7 +775,13 @@ int interpret_nth_last_branch(const char *name, struct strbuf *buf)
strbuf_init(&cb.buf[i], 20);
cb.cnt = 0;
retval = 0;
- for_each_reflog_ent("HEAD", grab_nth_branch_switch, &cb);
+ for_each_recent_reflog_ent("HEAD", grab_nth_branch_switch, 40960, &cb);
+ if (cb.cnt < nth) {
+ cb.cnt = 0;
+ for (i = 0; i < nth; i++)
+ strbuf_release(&cb.buf[i]);
+ for_each_reflog_ent("HEAD", grab_nth_branch_switch, &cb);
+ }
if (cb.cnt < nth)
goto release_return;
i = cb.cnt % nth;