shallow: add setup_temporary_shallow()

This function is like setup_alternate_shallow() except that it does
not lock $GIT_DIR/shallow.  It is supposed to be used when a program
generates temporary shallow for use by another program, then throw
the shallow file away.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/commit.h b/commit.h
index 790e31bec85d9e2e8bdd8533b7d69af4c0f18ca4..c4d324c9558bb7c785f17d35cf770be5e1f4bea9 100644 (file)
--- a/commit.h
+++ b/commit.h
@@ -201,6 +201,7 @@ extern void set_alternate_shallow_file(const char *path);
 extern int write_shallow_commits(struct strbuf *out, int use_pack_protocol);
 extern void setup_alternate_shallow(struct lock_file *shallow_lock,
                                    const char **alternate_shallow_file);
+extern char *setup_temporary_shallow(void);
 
 int is_descendant_of(struct commit *, struct commit_list *);
 int in_merge_bases(struct commit *, struct commit *);

diff --git a/shallow.c b/shallow.c
index 5f626c013890b60c991200434589425a0e16cef9..cdf37d694de175adcce10fa2e2a79c6579603b0b 100644 (file)
--- a/shallow.c
+++ b/shallow.c
@@ -175,6 +175,29 @@ int write_shallow_commits(struct strbuf *out, int use_pack_protocol)
        return data.count;
 }
 
+char *setup_temporary_shallow(void)
+{
+       struct strbuf sb = STRBUF_INIT;
+       int fd;
+
+       if (write_shallow_commits(&sb, 0)) {
+               struct strbuf path = STRBUF_INIT;
+               strbuf_addstr(&path, git_path("shallow_XXXXXX"));
+               fd = xmkstemp(path.buf);
+               if (write_in_full(fd, sb.buf, sb.len) != sb.len)
+                       die_errno("failed to write to %s",
+                                 path.buf);
+               close(fd);
+               strbuf_release(&sb);
+               return strbuf_detach(&path, NULL);
+       }
+       /*
+        * is_repository_shallow() sees empty string as "no shallow
+        * file".
+        */
+       return xstrdup("");
+}
+
 void setup_alternate_shallow(struct lock_file *shallow_lock,
                             const char **alternate_shallow_file)
 {