[PATCH v2] convert log_ref_write_fd() to use strbuf

[Ben Peart]

Since we don't care about how many bytes were written, simplify the return
value logic.

log_ref_write_fd() was written long before strbuf was fleshed out. Remove
the old manual buffer management code and replace it with strbuf(). Also
update copy_reflog_msg() which is called only by log_ref_write_fd() to use
strbuf as it keeps things consistent.

Signed-off-by: Ben Peart <ben.pe...@microsoft.com>
---

Notes:
    Base Ref: master
    Web-Diff: https://github.com/benpeart/git/commit/b72cd95643
    Checkout: git fetch https://github.com/benpeart/git refs-strbuf-v2 && git 
checkout b72cd95643
    
    ### Interdiff (v1..v2):
    
    diff --git a/refs/files-backend.c b/refs/files-backend.c
    index c0e892d0c8..054306d779 100644
    --- a/refs/files-backend.c
    +++ b/refs/files-backend.c
    @@ -1582,19 +1582,17 @@ static int log_ref_write_fd(int fd, const struct 
object_id *old_oid,
                            const struct object_id *new_oid,
                            const char *committer, const char *msg)
     {
    -   int written;
        struct strbuf sb = STRBUF_INIT;
    +   int ret = 0;
    
        strbuf_addf(&sb, "%s %s %s", oid_to_hex(old_oid), oid_to_hex(new_oid), 
committer);
        if (msg && *msg)
                copy_reflog_msg(&sb, msg);
        strbuf_addch(&sb, '\n');
    -   written = write_in_full(fd, sb.buf, sb.len);
    +   if (write_in_full(fd, sb.buf, sb.len) < 0)
    +           ret = -1;
        strbuf_release(&sb);
    -   if (written < 0)
    -           return -1;
    -
    -   return 0;
    +   return ret;
     }
    
     static int files_log_ref_write(struct files_ref_store *refs,
    
    ### Patches

 refs.c               | 12 ++++--------
 refs/files-backend.c | 29 ++++++++++-------------------
 refs/refs-internal.h |  7 +++----
 3 files changed, 17 insertions(+), 31 deletions(-)

diff --git a/refs.c b/refs.c
index 0eb379f931..50fe5c5d2c 100644
--- a/refs.c
+++ b/refs.c
@@ -786,25 +786,21 @@ int delete_ref(const char *msg, const char *refname,
                               old_oid, flags);
 }
 
-int copy_reflog_msg(char *buf, const char *msg)
+void copy_reflog_msg(struct strbuf *sb, const char *msg)
 {
-       char *cp = buf;
        char c;
        int wasspace = 1;
 
-       *cp++ = '\t';
+       strbuf_addch(sb, '\t');
        while ((c = *msg++)) {
                if (wasspace && isspace(c))
                        continue;
                wasspace = isspace(c);
                if (wasspace)
                        c = ' ';
-               *cp++ = c;
+               strbuf_addch(sb, c);
        }
-       while (buf < cp && isspace(cp[-1]))
-               cp--;
-       *cp++ = '\n';
-       return cp - buf;
+       strbuf_rtrim(sb);
 }
 
 int should_autocreate_reflog(const char *refname)
diff --git a/refs/files-backend.c b/refs/files-backend.c
index a9a066dcfb..054306d779 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -1582,26 +1582,17 @@ static int log_ref_write_fd(int fd, const struct 
object_id *old_oid,
                            const struct object_id *new_oid,
                            const char *committer, const char *msg)
 {
-       int msglen, written;
-       unsigned maxlen, len;
-       char *logrec;
-
-       msglen = msg ? strlen(msg) : 0;
-       maxlen = strlen(committer) + msglen + 100;
-       logrec = xmalloc(maxlen);
-       len = xsnprintf(logrec, maxlen, "%s %s %s\n",
-                       oid_to_hex(old_oid),
-                       oid_to_hex(new_oid),
-                       committer);
-       if (msglen)
-               len += copy_reflog_msg(logrec + len - 1, msg) - 1;
-
-       written = len <= maxlen ? write_in_full(fd, logrec, len) : -1;
-       free(logrec);
-       if (written < 0)
-               return -1;
+       struct strbuf sb = STRBUF_INIT;
+       int ret = 0;
 
-       return 0;
+       strbuf_addf(&sb, "%s %s %s", oid_to_hex(old_oid), oid_to_hex(new_oid), 
committer);
+       if (msg && *msg)
+               copy_reflog_msg(&sb, msg);
+       strbuf_addch(&sb, '\n');
+       if (write_in_full(fd, sb.buf, sb.len) < 0)
+               ret = -1;
+       strbuf_release(&sb);
+       return ret;
 }
 
 static int files_log_ref_write(struct files_ref_store *refs,
diff --git a/refs/refs-internal.h b/refs/refs-internal.h
index dd834314bd..17a526078f 100644
--- a/refs/refs-internal.h
+++ b/refs/refs-internal.h
@@ -91,11 +91,10 @@ enum peel_status {
 enum peel_status peel_object(const struct object_id *name, struct object_id 
*oid);
 
 /*
- * Copy the reflog message msg to buf, which has been allocated sufficiently
- * large, while cleaning up the whitespaces.  Especially, convert LF to space,
- * because reflog file is one line per entry.
+ * Copy the reflog message msg to sb while cleaning up the whitespaces.
+ * Especially, convert LF to space, because reflog file is one line per entry.
  */
-int copy_reflog_msg(char *buf, const char *msg);
+void copy_reflog_msg(struct strbuf *sb, const char *msg);
 
 /**
  * Information needed for a single ref update. Set new_oid to the new

base-commit: e3331758f12da22f4103eec7efe1b5304a9be5e9
-- 
2.17.0.gvfs.1.123.g449c066