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[PATCH v2 09/18] do_for_each_reflog(): reuse strbuf across recursive function calls

From
mhagger@alum.mit.edu <mhagger@alum.mit.edu>
Date
Apr 26, 2012, 22:26 UTC
Message-ID
<1335479227-7877-10-git-send-email-mhagger@alum.mit.edu>
In-Reply-To
<1335479227-7877-1-git-send-email-mhagger@alum.mit.edu>
From: Michael Haggerty <mhagger@alum.mit.edu>

This saves some memory allocations. Also require that the name argument end in slash, which removes some extra bookkeeping.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
---
 refs.c |   45 +++++++++++++++++++++++----------------------
 1 file changed, 23 insertions(+), 22 deletions(-)
diff --git a/refs.c b/refs.c
index f43c255..989c10d 100644
--- a/refs.c
+++ b/refs.c
@@ -2242,24 +2242,20 @@ int for_each_reflog_ent(const char *refname, each_reflog_ent_fn fn, void *cb_dat
 	return for_each_recent_reflog_ent(refname, fn, 0, cb_data);
 }
 
-static int do_for_each_reflog(const char *base, each_ref_fn fn, void *cb_data)
+/*
+ * Call fn for each reflog in the namespace indicated by name.  name
+ * must be empty or end with '/'.  Name will be used as a scratch
+ * space, but its contents will be restored before return.
+ */
+static int do_for_each_reflog(struct strbuf *name, each_ref_fn fn, void *cb_data)
 {
-	DIR *d = opendir(git_path("logs/%s", base));
+	DIR *d = opendir(git_path("logs/%s", name->buf));
 	int retval = 0;
 	struct dirent *de;
-	int baselen;
-	struct strbuf log;
+	int oldlen = name->len;
 
 	if (!d)
-		return *base ? errno : 0;
-
-	baselen = strlen(base);
-	strbuf_init(&log, baselen + 257);
-	strbuf_add(&log, base, baselen);
-	if (log.len && log.buf[log.len-1] != '/') {
-		strbuf_addch(&log, '/');
-		baselen++;
-	}
+		return name->len ? errno : 0;
 
 	while ((de = readdir(d)) != NULL) {
 		struct stat st;
@@ -2268,32 +2264,37 @@ static int do_for_each_reflog(const char *base, each_ref_fn fn, void *cb_data)
 			continue;
 		if (has_extension(de->d_name, ".lock"))
 			continue;
-		strbuf_addstr(&log, de->d_name);
-		if (stat(git_path("logs/%s", log.buf), &st) < 0) {
+		strbuf_addstr(name, de->d_name);
+		if (stat(git_path("logs/%s", name->buf), &st) < 0) {
 			/* Silently ignore. */
 		} else {
 			if (S_ISDIR(st.st_mode)) {
-				retval = do_for_each_reflog(log.buf, fn, cb_data);
+				strbuf_addch(name, '/');
+				retval = do_for_each_reflog(name, fn, cb_data);
 			} else {
 				unsigned char sha1[20];
-				if (read_ref_full(log.buf, sha1, 0, NULL))
-					retval = error("bad ref for %s", log.buf);
+				if (read_ref_full(name->buf, sha1, 0, NULL))
+					retval = error("bad ref for %s", name->buf);
 				else
-					retval = fn(log.buf, sha1, 0, cb_data);
+					retval = fn(name->buf, sha1, 0, cb_data);
 			}
 			if (retval)
 				break;
 		}
-		strbuf_setlen(&log, baselen);
+		strbuf_setlen(name, oldlen);
 	}
-	strbuf_release(&log);
 	closedir(d);
 	return retval;
 }
 
 int for_each_reflog(each_ref_fn fn, void *cb_data)
 {
-	return do_for_each_reflog("", fn, cb_data);
+	int retval;
+	struct strbuf name;
+	strbuf_init(&name, PATH_MAX);
+	retval = do_for_each_reflog(&name, fn, cb_data);
+	strbuf_release(&name);
+	return retval;
 }
 
 int update_ref(const char *action, const char *refname,
-- 
1.7.10
Previous: Michael HaggertyNext: mhagger@alum.mit.edu
Message 17 of 26 in “Read loose references lazily”
  1. 00/18 Read loose references lazilymhagger@alum.mit.edu, Apr 26, 2012
  2. 01/18 get_ref_dir(): return early if directory cannot be readmhagger@alum.mit.edu, Apr 26, 2012
  3. 02/18 get_ref_dir(): use a strbuf to hold refnamemhagger@alum.mit.edu, Apr 26, 2012
  4. 03/18 get_ref_dir(): rename "base" parameter to "dirname"mhagger@alum.mit.edu, Apr 26, 2012
  5. 04/18 get_ref_dir(): require that the dirname argument ends in '/'mhagger@alum.mit.edu, Apr 26, 2012
  6. 05/18 refs.c: extract function search_for_subdir()mhagger@alum.mit.edu, Apr 26, 2012
  7. Junio C HamanoMay 3, 2012
  8. Junio C HamanoMay 3, 2012
  9. Michael HaggertyMay 4, 2012
  10. 06/18 get_ref_dir(): take the containing directory as argumentmhagger@alum.mit.edu, Apr 26, 2012
  11. 07/18 do_for_each_reflog(): return early on errormhagger@alum.mit.edu, Apr 26, 2012
  12. 08/18 do_for_each_reflog(): use a strbuf to hold logfile namemhagger@alum.mit.edu, Apr 26, 2012
  13. Junio C HamanoApr 26, 2012
  14. Michael HaggertyApr 27, 2012
  15. Junio C HamanoMay 2, 2012
  16. Michael HaggertyMay 3, 2012
  17. 09/18 do_for_each_reflog(): reuse strbuf across recursive function callsmhagger@alum.mit.edu, Apr 26, 2012
  18. 10/18 bisect: copy filename string obtained from git_path()mhagger@alum.mit.edu, Apr 26, 2012
  19. 11/18 find_containing_dir(): use strbuf in implementation of this functionmhagger@alum.mit.edu, Apr 26, 2012
  20. 12/18 refs: wrap top-level ref_dirs in ref_entriesmhagger@alum.mit.edu, Apr 26, 2012
  21. 13/18 read_loose_refs(): rename function from get_ref_dir()mhagger@alum.mit.edu, Apr 26, 2012
  22. 14/18 get_ref_dir(): add function for getting a ref_dir from a ref_entrymhagger@alum.mit.edu, Apr 26, 2012
  23. 15/18 search_for_subdir(): return (ref_dir *) instead of (ref_entry *)mhagger@alum.mit.edu, Apr 26, 2012
  24. 16/18 struct ref_dir: store a reference to the enclosing ref_cachemhagger@alum.mit.edu, Apr 26, 2012
  25. 17/18 read_loose_refs(): eliminate ref_cache argumentmhagger@alum.mit.edu, Apr 26, 2012
  26. 18/18 refs: read loose references lazilymhagger@alum.mit.edu, Apr 26, 2012

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