abspath: make strip_last_path_component() global

The strip_last_component() method is helpful for finding the parent
directory of a path stored in a strbuf. Extract it to a global method
advertised in abspath.h. With that additional visibility, it is helpful to
rename it to be more specific to paths.

Signed-off-by: Derrick Stolee <derrickstolee@github.com>

abspath.c

@@ -14,7 +14,7 @@ int is_directory(const char *path)
 }
 
 /* removes the last path component from 'path' except if 'path' is root */
-static void strip_last_component(struct strbuf *path)
+void strip_last_path_component(struct strbuf *path)
 {
 	size_t offset = offset_1st_component(path->buf);
 	size_t len = path->len;
@@ -119,7 +119,7 @@ static char *strbuf_realpath_1(struct strbuf *resolved, const char *path,
 			continue; /* '.' component */
 		} else if (next.len == 2 && !strcmp(next.buf, "..")) {
 			/* '..' component; strip the last path component */
-			strip_last_component(resolved);
+			strip_last_path_component(resolved);
 			continue;
 		}
 
@@ -171,7 +171,7 @@ static char *strbuf_realpath_1(struct strbuf *resolved, const char *path,
 				 * strip off the last component since it will
 				 * be replaced with the contents of the symlink
 				 */
-				strip_last_component(resolved);
+				strip_last_path_component(resolved);
 			}
 
 			/*

abspath.h

@@ -10,6 +10,11 @@ char *real_pathdup(const char *path, int die_on_error);
 const char *absolute_path(const char *path);
 char *absolute_pathdup(const char *path);
 
+/**
+ * Remove the last path component from 'path' except if 'path' is root.
+ */
+void strip_last_path_component(struct strbuf *path);
+
 /*
  * Concatenate "prefix" (if len is non-zero) and "path", with no
  * connecting characters (so "prefix" should end with a "/").