[PATCH/POC 6/7] setup.c: add split-repo support to setup_git_directory*

["Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>]

XXX bare repos probably not worth supporting..

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 cache.h       |  1 +
 environment.c | 19 ++++++++++++++++--
 setup.c       | 62 +++++++++++++++++++++++++++++++++++++++--------------------
 trace.c       |  1 +
 4 files changed, 60 insertions(+), 23 deletions(-)

diff --git a/cache.h b/cache.h
index f85ee70..4c09223 100644
--- a/cache.h
+++ b/cache.h
@@ -406,6 +406,7 @@ extern char *get_object_directory(void);
 extern char *get_index_file(void);
 extern char *get_graft_file(void);
 extern int set_git_dir(const char *path);
+extern int set_git_dir_super(const char *path, const char *super);
 extern const char *get_git_namespace(void);
 extern const char *strip_namespace(const char *namespaced_ref);
 extern const char *get_git_work_tree(void);
diff --git a/environment.c b/environment.c
index d5ae7a3..8152c7e 100644
--- a/environment.c
+++ b/environment.c
@@ -125,13 +125,17 @@ static char *expand_namespace(const char *raw_namespace)
 static void setup_git_env(void)
 {
 	const char *gitfile;
+	char *super;
 
 	git_dir = getenv(GIT_DIR_ENVIRONMENT);
 	if (!git_dir)
 		git_dir = DEFAULT_GIT_DIR_ENVIRONMENT;
-	gitfile = read_gitfile(git_dir);
+	gitfile = read_gitfile_super(git_dir, &super);
 	git_dir = xstrdup(gitfile ? gitfile : git_dir);
-	git_super_dir = getenv(GIT_SUPER_DIR_ENVIRONMENT);
+	if (super)
+		git_super_dir = xstrdup(super);
+	else
+		git_super_dir = getenv(GIT_SUPER_DIR_ENVIRONMENT);
 	git_object_dir = getenv(DB_ENVIRONMENT);
 	if (!git_object_dir) {
 		git_object_dir = xmalloc(strlen(git_dir) + 9);
@@ -280,6 +284,17 @@ int set_git_dir(const char *path)
 	return 0;
 }
 
+int set_git_dir_super(const char *path, const char *super)
+{
+	if (super != path &&
+	    setenv(GIT_SUPER_DIR_ENVIRONMENT, super, 1))
+		return error("Could not set GIT_SUPER_DIR to '%s'", super);
+	if (setenv(GIT_DIR_ENVIRONMENT, path, 1))
+		return error("Could not set GIT_DIR to '%s'", path);
+	setup_git_env();
+	return 0;
+}
+
 const char *get_log_output_encoding(void)
 {
 	return git_log_output_encoding ? git_log_output_encoding
diff --git a/setup.c b/setup.c
index dfe9d08..f22381e 100644
--- a/setup.c
+++ b/setup.c
@@ -255,7 +255,8 @@ void setup_work_tree(void)
 	if (getenv(GIT_WORK_TREE_ENVIRONMENT))
 		setenv(GIT_WORK_TREE_ENVIRONMENT, ".", 1);
 
-	set_git_dir(remove_leading_path(git_dir, work_tree));
+	set_git_dir_super(remove_leading_path(git_dir, work_tree),
+			  get_git_super_dir());
 	initialized = 1;
 }
 
@@ -368,24 +369,28 @@ const char *read_gitfile(const char *path)
 
 
 static const char *setup_explicit_git_dir(const char *gitdirenv,
+					  const char *super_,
 					  char *cwd, int len,
 					  int *nongit_ok)
 {
 	const char *work_tree_env = getenv(GIT_WORK_TREE_ENVIRONMENT);
 	const char *worktree;
-	char *gitfile;
+	char *gitfile, *super = (char *)super_;
 	int offset;
 
 	if (PATH_MAX - 40 < strlen(gitdirenv))
 		die("'$%s' too big", GIT_DIR_ENVIRONMENT);
 
-	gitfile = (char*)read_gitfile(gitdirenv);
+	gitfile = (char*)read_gitfile_super(gitdirenv, !super ? &super : NULL);
 	if (gitfile) {
 		gitfile = xstrdup(gitfile);
 		gitdirenv = gitfile;
-	}
+		if (!super)
+			super = gitfile;
+	} else if (!super)
+		super = (char *)gitdirenv;
 
-	if (!is_git_directory(gitdirenv)) {
+	if (!is_git_directory_super(gitdirenv, super)) {
 		if (nongit_ok) {
 			*nongit_ok = 1;
 			goto done_null;
@@ -393,7 +398,7 @@ static const char *setup_explicit_git_dir(const char *gitdirenv,
 		die("Not a git repository: '%s'", gitdirenv);
 	}
 
-	if (check_repository_format_gently(gitdirenv, nongit_ok))
+	if (check_repository_format_gently(super, nongit_ok))
 		goto done_null;
 
 	/* #3, #7, #11, #15, #19, #23, #27, #31 (see t1510) */
@@ -404,7 +409,7 @@ static const char *setup_explicit_git_dir(const char *gitdirenv,
 			die("core.bare and core.worktree do not make sense");
 
 		/* #18, #26 */
-		set_git_dir(gitdirenv);
+		set_git_dir_super(gitdirenv, super);
 		goto done_null;
 	}
 	else if (git_work_tree_cfg) { /* #6, #14 */
@@ -425,7 +430,7 @@ static const char *setup_explicit_git_dir(const char *gitdirenv,
 	}
 	else if (!git_env_bool(GIT_IMPLICIT_WORK_TREE_ENVIRONMENT, 1)) {
 		/* #16d */
-		set_git_dir(gitdirenv);
+		set_git_dir_super(gitdirenv, super);
 		goto done_null;
 	}
 	else /* #2, #10 */
@@ -436,34 +441,39 @@ static const char *setup_explicit_git_dir(const char *gitdirenv,
 
 	/* both get_git_work_tree() and cwd are already normalized */
 	if (!strcmp(cwd, worktree)) { /* cwd == worktree */
-		set_git_dir(gitdirenv);
+		set_git_dir_super(gitdirenv, super);
 		goto done_null;
 	}
 
 	offset = dir_inside_of(cwd, worktree);
 	if (offset >= 0) {	/* cwd inside worktree? */
-		set_git_dir(real_path(gitdirenv));
+		set_git_dir_super(real_path(gitdirenv), super);
 		if (chdir(worktree))
 			die_errno("Could not chdir to '%s'", worktree);
 		cwd[len++] = '/';
 		cwd[len] = '\0';
 		free(gitfile);
+		if (super != gitdirenv && super != super_)
+			free(super);
 		return cwd + offset;
 	}
 
 	/* cwd outside worktree */
-	set_git_dir(gitdirenv);
+	set_git_dir_super(gitdirenv, super);
 
 done_null:
 	free(gitfile);
+	if (super != gitdirenv && super != super_)
+		free(super);
 	return NULL;
 }
 
 static const char *setup_discovered_git_dir(const char *gitdir,
+					    const char *super,
 					    char *cwd, int offset, int len,
 					    int *nongit_ok)
 {
-	if (check_repository_format_gently(gitdir, nongit_ok))
+	if (check_repository_format_gently(super, nongit_ok))
 		return NULL;
 
 	/* --work-tree is set without --git-dir; use discovered one */
@@ -472,7 +482,7 @@ static const char *setup_discovered_git_dir(const char *gitdir,
 			gitdir = xstrdup(real_path(gitdir));
 		if (chdir(cwd))
 			die_errno("Could not come back to cwd");
-		return setup_explicit_git_dir(gitdir, cwd, len, nongit_ok);
+		return setup_explicit_git_dir(gitdir, super, cwd, len, nongit_ok);
 	}
 
 	/* #16.2, #17.2, #20.2, #21.2, #24, #25, #28, #29 (see t1510) */
@@ -486,7 +496,7 @@ static const char *setup_discovered_git_dir(const char *gitdir,
 	/* #0, #1, #5, #8, #9, #12, #13 */
 	set_git_work_tree(".");
 	if (strcmp(gitdir, DEFAULT_GIT_DIR_ENVIRONMENT))
-		set_git_dir(gitdir);
+		set_git_dir_super(gitdir, super);
 	inside_git_dir = 0;
 	inside_work_tree = 1;
 	if (offset == len)
@@ -516,7 +526,7 @@ static const char *setup_bare_git_dir(char *cwd, int offset, int len, int *nongi
 		gitdir = offset == len ? "." : xmemdupz(cwd, offset);
 		if (chdir(cwd))
 			die_errno("Could not come back to cwd");
-		return setup_explicit_git_dir(gitdir, cwd, len, nongit_ok);
+		return setup_explicit_git_dir(gitdir, NULL, cwd, len, nongit_ok);
 	}
 
 	inside_git_dir = 1;
@@ -596,7 +606,7 @@ static const char *setup_git_directory_gently_1(int *nongit_ok)
 	struct string_list ceiling_dirs = STRING_LIST_INIT_DUP;
 	static char cwd[PATH_MAX + 1];
 	const char *gitdirenv, *ret;
-	char *gitfile;
+	char *gitfile, *super;
 	int len, offset, offset_parent, ceil_offset = -1;
 	dev_t current_device = 0;
 	int one_filesystem = 1;
@@ -620,7 +630,9 @@ static const char *setup_git_directory_gently_1(int *nongit_ok)
 	 */
 	gitdirenv = getenv(GIT_DIR_ENVIRONMENT);
 	if (gitdirenv)
-		return setup_explicit_git_dir(gitdirenv, cwd, len, nongit_ok);
+		return setup_explicit_git_dir(gitdirenv,
+					      getenv(GIT_SUPER_DIR_ENVIRONMENT),
+					      cwd, len, nongit_ok);
 
 	if (env_ceiling_dirs) {
 		int empty_entry_found = 0;
@@ -650,21 +662,29 @@ static const char *setup_git_directory_gently_1(int *nongit_ok)
 	if (one_filesystem)
 		current_device = get_device_or_die(".", NULL, 0);
 	for (;;) {
-		gitfile = (char*)read_gitfile(DEFAULT_GIT_DIR_ENVIRONMENT);
-		if (gitfile)
+		gitfile = (char*)read_gitfile_super(DEFAULT_GIT_DIR_ENVIRONMENT,
+						    &super);
+		if (gitfile) {
 			gitdirenv = gitfile = xstrdup(gitfile);
-		else {
+			if (!super)
+				super = gitfile;
+		} else {
 			if (is_git_directory(DEFAULT_GIT_DIR_ENVIRONMENT))
 				gitdirenv = DEFAULT_GIT_DIR_ENVIRONMENT;
+			super = (char *)gitdirenv;
 		}
 
 		if (gitdirenv) {
-			ret = setup_discovered_git_dir(gitdirenv,
+			ret = setup_discovered_git_dir(gitdirenv, super,
 						       cwd, offset, len,
 						       nongit_ok);
+			if (super != gitdirenv)
+				free(super);
 			free(gitfile);
 			return ret;
 		}
+		if (super != gitdirenv)
+			free(super);
 		free(gitfile);
 
 		if (is_git_directory("."))
diff --git a/trace.c b/trace.c
index 3d744d1..53d800b 100644
--- a/trace.c
+++ b/trace.c
@@ -173,6 +173,7 @@ void trace_repo_setup(const char *prefix)
 		prefix = "(null)";
 
 	trace_printf_key(key, "setup: git_dir: %s\n", quote_crnl(get_git_dir()));
+	trace_printf_key(key, "setup: git_super_dir: %s\n", quote_crnl(get_git_super_dir()));
 	trace_printf_key(key, "setup: worktree: %s\n", quote_crnl(git_work_tree));
 	trace_printf_key(key, "setup: cwd: %s\n", quote_crnl(cwd));
 	trace_printf_key(key, "setup: prefix: %s\n", quote_crnl(prefix));
-- 
1.8.5.1.77.g42c48fa