[PATCH 2/2] worktree: provide better prefix to go back to original cwd

From

pclouds@gmail.com <pclouds@gmail.com>

Date

Oct 7, 2010, 04:46 UTC

Message-ID

<4cad50da.0e958e0a.40e3.5efd@mx.google.com>

In-Reply-To

<y>

From: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>

$ GIT_DIR=foo/.git GIT_WORK_TREE=foo git blah bar

or "path in file system":

$ GIT_DIR=foo/.git GIT_WORK_TREE=foo git blah foo/bar

 - detect this case, via is_inside_work_tree()

 - enter_work_tree() (not strictly needed, but I believe it would
   less work this way)

 - prepend startup_info->cwd_to_worktree to output so it becomes
   relative to original cwd

 - prepend startup_info->worktree_to_cwd to command line arguments
   if they are meant to access file system

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 I don't care Windows UNC path. And I did not test the case
 where cwd is on C:\ while worktree is on another drive.

 As stated elsewhere, I neglect other cases where cwd may be
 outside worktree. The goal of these patches is to help
 Chris' grep series. If it works out, I'll fix the rest.

 Sorry Chris, I think I have dragged you into worktree setup
 mess.

 builtin/rev-parse.c        |   10 ++++
 cache.h                    |    2 +
 setup.c                    |  119 ++++++++++++++++++++++++++++++++++++++++++--
 t/t1510-worktree-prefix.sh |   52 +++++++++++++++++++
 4 files changed, 179 insertions(+), 4 deletions(-)
 create mode 100755 t/t1510-worktree-prefix.sh

diff --git a/builtin/rev-parse.c b/builtin/rev-parse.c
index a5a1c86..525610e 100644
--- a/builtin/rev-parse.c
+++ b/builtin/rev-parse.c
@@ -623,6 +623,16 @@ int cmd_rev_parse(int argc, const char **argv, const char *prefix)
 					puts(prefix);
 				continue;
 			}
+			if (!strcmp(arg, "--cwd-to-worktree")) {
+				if (startup_info->cwd_to_worktree)
+					puts(startup_info->cwd_to_worktree);
+				continue;
+			}
+			if (!strcmp(arg, "--worktree-to-cwd")) {
+				if (startup_info->worktree_to_cwd)
+					puts(startup_info->worktree_to_cwd);
+				continue;
+			}
 			if (!strcmp(arg, "--show-cdup")) {
 				const char *pfx = prefix;
 				if (!is_inside_work_tree()) {
diff --git a/cache.h b/cache.h
index e71db23..be35b8f 100644
--- a/cache.h
+++ b/cache.h
@@ -1111,6 +1111,8 @@ const char *split_cmdline_strerror(int cmdline_errno);
 /* git.c */
 struct startup_info {
 	int have_repository;
+	char *cwd_to_worktree; /* path from original cwd to worktree */
+	char *worktree_to_cwd; /* path from worktree to original cwd */
 };
 extern struct startup_info *startup_info;
 
diff --git a/setup.c b/setup.c
index 3fbe928..1f5117a 100644
--- a/setup.c
+++ b/setup.c
@@ -320,10 +320,120 @@ const char *read_gitfile_gently(const char *path)
 	return path;
 }
 
+/*
+ * Given "foo/bar" and "hey/hello/world", return "../../hey/hello/world/"
+ * Either path1 or path2 can be NULL. All must be canonical.
+ */
+static char *make_path_to_path(const char *path1, const char *path2)
+{
+	int nr_back = 0;
+	int i, pathlen = path2 ? strlen(path2) : 0;
+	char *buf, *p;
+
+	if (path1 && *path1) {
+		nr_back = 1;
+		while (*path1) {
+			if (is_dir_sep(*path1))
+				nr_back++;
+			path1++;
+		}
+	}
+
+	if (!nr_back && !pathlen)
+		return NULL;
+
+	p = buf = xmalloc(3*nr_back + pathlen + 2); /* "../"^nr_back + path2 + '/' + NULL */
+	for (i = 0; i < nr_back; i++) {
+		memcpy(p, "../", 3);
+		p += 3;
+	}
+	if (pathlen) {
+		memcpy(p, path2, pathlen);
+		p += pathlen;
+		if (p[-1] != '/') /* path2 may be c:/, don't put another slash  */
+			*p++ = '/';
+	}
+	*p = '\0';
+	return buf;
+}
+
+/*
+ * Return a prefix if cwd inside worktree, or NULL otherwise.
+ * Also fill startup_info struct.
+ */
+static const char *setup_prefix(const char *cwd)
+{
+	const char *worktree = get_git_work_tree();
+	int len = 0, cwd_len = strlen(cwd), worktree_len = strlen(worktree);
+
+	while (worktree[len] && worktree[len] == cwd[len])
+		len++;
+
+	if (!worktree[len] && !cwd[len]) {
+		if (startup_info) {
+			startup_info->cwd_to_worktree = NULL;
+			startup_info->worktree_to_cwd = NULL;
+		}
+		return NULL;
+	}
+	/* get /foo/, not /foo/baa if /foo/baa1 and /foo/baa2 are given */
+	else if (worktree[len] && cwd[len]) {
+		while (len && !is_dir_sep(worktree[len]))
+			len--;
+		len++;
+
+		/* Worktree and cwd are on different drives? */
+		if (len == 3 && has_dos_drive_prefix(cwd)) {
+			if (startup_info) {
+				/* make_path_to_path will add the trailing slash */
+				startup_info->cwd_to_worktree = make_path_to_path(NULL, worktree);
+				startup_info->worktree_to_cwd = make_path_to_path(NULL, cwd);
+			}
+			return NULL;
+		}
+	}
+	else {
+		if (worktree[len]) {
+			if (!is_dir_sep(worktree[len])) {
+				while (len && !is_dir_sep(worktree[len]))
+					len--;
+			}
+		}
+		else {
+			if (!is_dir_sep(cwd[len])) {
+				while (len && !is_dir_sep(cwd[len]))
+					len--;
+			}
+		}
+		len++;		/* must be a slash here, skip it */
+	}
+
+	if (len < cwd_len && len < worktree_len) {
+		if (startup_info) {
+			startup_info->cwd_to_worktree = make_path_to_path(cwd+len, worktree+len);
+			startup_info->worktree_to_cwd = make_path_to_path(worktree+len, cwd+len);
+		}
+		return NULL;
+	}
+
+	if (startup_info) {
+		if (len < cwd_len) { /* cwd inside worktree */
+			startup_info->cwd_to_worktree = make_path_to_path(cwd+len, NULL);
+			startup_info->worktree_to_cwd = make_path_to_path(NULL, cwd+len);
+		}
+		else {
+			startup_info->cwd_to_worktree = make_path_to_path(NULL, worktree+len);
+			startup_info->worktree_to_cwd = make_path_to_path(worktree+len, NULL);
+		}
+	}
+
+	return len < cwd_len ? cwd+len : NULL;
+}
+
 static const char *setup_explicit_git_dir(const char *gitdirenv,
 				const char *work_tree_env, int *nongit_ok)
 {
-	static char buffer[1024 + 1];
+	static char buffer[PATH_MAX];
 	const char *retval;
 
 	if (PATH_MAX - 40 < strlen(gitdirenv))
@@ -344,9 +454,10 @@ static const char *setup_explicit_git_dir(const char *gitdirenv,
 	}
 	if (check_repository_format_gently(nongit_ok))
 		return NULL;
-	retval = get_relative_cwd(buffer, sizeof(buffer) - 1,
-			get_git_work_tree());
-	if (!retval || !*retval)
+	if (!getcwd(buffer, sizeof(buffer)))
+		die_errno("can't find the current directory");
+	retval = setup_prefix(buffer);
+	if (!retval)
 		return NULL;
 	set_git_dir(make_absolute_path(gitdirenv));
 	if (chdir(work_tree_env) < 0)
diff --git a/t/t1510-worktree-prefix.sh b/t/t1510-worktree-prefix.sh
new file mode 100755
index 0000000..3839493
--- /dev/null
+++ b/t/t1510-worktree-prefix.sh
@@ -0,0 +1,52 @@
+#!/bin/sh
+
+test_description='test rev-parse --cwd-to-worktree and --worktree-to-cwd'
+
+. ./test-lib.sh
+
+test_expect_success 'setup' '
+	mkdir foo bar &&
+	mv .git foo &&
+	mkdir foo/bar &&
+	GIT_DIR=`pwd`/foo/.git &&
+	GIT_WORK_TREE=`pwd`/foo &&
+	export GIT_DIR GIT_WORK_TREE
+'
+
+test_expect_success 'at root' '
+	(
+	cd foo &&
+	git rev-parse --cwd-to-worktree --worktree-to-cwd >result &&
+	: >expected &&
+	test_cmp expected result
+	)
+'
+
+test_expect_success 'cwd inside worktree' '
+	(
+	cd foo/bar &&
+	git rev-parse --cwd-to-worktree --worktree-to-cwd >result &&
+	echo ../ >expected &&
+	echo bar/ >>expected &&
+	test_cmp expected result
+	)
+'
+
+test_expect_success 'cwd outside worktree' '
+	git rev-parse --cwd-to-worktree --worktree-to-cwd >result &&
+	echo foo/ >expected &&
+	echo ../ >>expected &&
+	test_cmp expected result
+'
+
+test_expect_success 'cwd outside worktree (2)' '
+	(
+	cd bar &&
+	git rev-parse --cwd-to-worktree --worktree-to-cwd >result &&
+	echo ../foo/ >expected &&
+	echo ../bar/ >>expected &&
+	test_cmp expected result
+	)
+'
+
+test_done

-- 
1.7.1.rc1.70.g788ca