[PATCH 2/8] strbuf.c: reintroduce get_pwd_cwd() (with strbuf_ prefix)

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

From: Duy Nguyen <pclouds@gmail.com>

This function was added in 10c4c881c4 (Allow add_path() to add
non-existent directories to the path - 2008-07-21) because getcwd()
may fail on non-existing cwd and we want to construct non-existing
absolute paths sometimes.

The function was merged back in strbuf_add_absolute_path() some time
later. Move it out again because it will have another caller shortly.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 strbuf.c | 37 ++++++++++++++++++++++---------------
 strbuf.h |  6 ++++++
 2 files changed, 28 insertions(+), 15 deletions(-)

diff --git a/strbuf.c b/strbuf.c
index d5b7cda61e..aed4bec856 100644
--- a/strbuf.c
+++ b/strbuf.c
@@ -746,27 +746,34 @@ void strbuf_humanise_bytes(struct strbuf *buf, off_t bytes)
 	}
 }
 
+void strbuf_get_pwd_cwd(struct strbuf *sb)
+{
+	struct stat cwd_stat, pwd_stat;
+	char *cwd = xgetcwd();
+	char *pwd = getenv("PWD");
+
+	if (pwd && strcmp(pwd, cwd) &&
+	    !stat(cwd, &cwd_stat) &&
+	    (cwd_stat.st_dev || cwd_stat.st_ino) &&
+	    !stat(pwd, &pwd_stat) &&
+	    pwd_stat.st_dev == cwd_stat.st_dev &&
+	    pwd_stat.st_ino == cwd_stat.st_ino)
+		strbuf_addstr(sb, pwd);
+	else
+		strbuf_addstr(sb, cwd);
+	free(cwd);
+}
+
 void strbuf_add_absolute_path(struct strbuf *sb, const char *path)
 {
 	if (!*path)
 		die("The empty string is not a valid path");
 	if (!is_absolute_path(path)) {
-		struct stat cwd_stat, pwd_stat;
 		size_t orig_len = sb->len;
-		char *cwd = xgetcwd();
-		char *pwd = getenv("PWD");
-		if (pwd && strcmp(pwd, cwd) &&
-		    !stat(cwd, &cwd_stat) &&
-		    (cwd_stat.st_dev || cwd_stat.st_ino) &&
-		    !stat(pwd, &pwd_stat) &&
-		    pwd_stat.st_dev == cwd_stat.st_dev &&
-		    pwd_stat.st_ino == cwd_stat.st_ino)
-			strbuf_addstr(sb, pwd);
-		else
-			strbuf_addstr(sb, cwd);
-		if (sb->len > orig_len && !is_dir_sep(sb->buf[sb->len - 1]))
-			strbuf_addch(sb, '/');
-		free(cwd);
+
+		strbuf_get_pwd_cwd(sb);
+		if (sb->len > orig_len)
+			strbuf_ensure_trailing_dir_sep(sb);
 	}
 	strbuf_addstr(sb, path);
 }
diff --git a/strbuf.h b/strbuf.h
index 62dc7f16fa..f712c4ff92 100644
--- a/strbuf.h
+++ b/strbuf.h
@@ -458,6 +458,12 @@ extern int strbuf_getwholeline_fd(struct strbuf *, int, int);
  */
 extern int strbuf_getcwd(struct strbuf *sb);
 
+/**
+ * Return the current directory, fall back to $PWD if the
+ * current directory does not exist.
+ */
+extern void strbuf_get_pwd_cwd(struct strbuf *sb);
+
 /**
  * Add a path to a buffer, converting a relative path to an
  * absolute one in the process.  Symbolic links are not
-- 
2.17.0.rc1.439.gca064e2955