[PATCH 2/4] submodule.c: factor start_ls_files_dot_dot out of get_superproject_working_tree

[Stefan Beller]

We'll reuse the code of the factored out function shortly, when exploring
the superproject for another aspect. Instead of knowing the root of the
superproject we'll find out about the gitlink value.

Signed-off-by: Stefan Beller <sbel...@google.com>
---
 submodule.c | 53 ++++++++++++++++++++++++++++++++++-------------------
 1 file changed, 34 insertions(+), 19 deletions(-)

diff --git a/submodule.c b/submodule.c
index 239d94d539..4fcb64469e 100644
--- a/submodule.c
+++ b/submodule.c
@@ -1977,15 +1977,13 @@ void absorb_git_dir_into_superproject(const char 
*prefix,
        }
 }
 
-const char *get_superproject_working_tree(void)
+/* Starts a child process `ls-files` one directory above the root of the repo. 
*/
+static int start_ls_files_dot_dot(struct child_process *cp, struct strbuf *out)
 {
-       struct child_process cp = CHILD_PROCESS_INIT;
-       struct strbuf sb = STRBUF_INIT;
        const char *one_up = real_path_if_valid("../");
-       const char *cwd = xgetcwd();
-       const char *ret = NULL;
        const char *subpath;
-       int code;
+       char *cwd = xgetcwd();
+       struct strbuf sb = STRBUF_INIT;
        ssize_t len;
 
        if (!is_inside_work_tree())
@@ -1994,31 +1992,48 @@ const char *get_superproject_working_tree(void)
                 * We might have a superproject, but it is harder
                 * to determine.
                 */
-               return NULL;
+               return -1;
 
        if (!one_up)
-               return NULL;
+               return -1;
 
        subpath = relative_path(cwd, one_up, &sb);
 
-       prepare_submodule_repo_env(&cp.env_array);
-       argv_array_pop(&cp.env_array);
+       prepare_submodule_repo_env(&cp->env_array);
+       argv_array_pop(&cp->env_array);
 
-       argv_array_pushl(&cp.args, "--literal-pathspecs", "-C", "..",
+       argv_array_pushl(&cp->args, "--literal-pathspecs", "-C", "..",
                        "ls-files", "-z", "--stage", "--full-name", "--",
                        subpath, NULL);
-       strbuf_reset(&sb);
 
-       cp.no_stdin = 1;
-       cp.no_stderr = 1;
-       cp.out = -1;
-       cp.git_cmd = 1;
+       cp->no_stdin = 1;
+       cp->no_stderr = 1;
+       cp->out = -1;
+       cp->git_cmd = 1;
 
-       if (start_command(&cp))
+       if (start_command(cp))
                die(_("could not start ls-files in .."));
 
-       len = strbuf_read(&sb, cp.out, PATH_MAX);
-       close(cp.out);
+       len = strbuf_read(out, cp->out, PATH_MAX);
+       close(cp->out);
+
+       strbuf_release(&sb);
+       free(cwd);
+       return len;
+}
+
+const char *get_superproject_working_tree(void)
+{
+       struct child_process cp = CHILD_PROCESS_INIT;
+       struct strbuf sb = STRBUF_INIT;
+       const char *cwd = xgetcwd();
+       const char *ret = NULL;
+       int code;
+       ssize_t len;
+
+       len = start_ls_files_dot_dot(&cp, &sb);
+       if (len < 0)
+               return NULL;
 
        if (starts_with(sb.buf, "160000")) {
                int super_sub_len;
-- 
2.15.0.128.g40905b34bf.dirty