[ccache] [PATCH] Potentially produce better relative pathnames when symlinks are

[Mike Crowe]

When making relative pathnames try and do so both before and after
calling realpath and pick the version that is the shortest. This helps
if the build starts from a path that contains a symlink and a Makefile
somewhere decides to use realpath to generate absolute paths.

It might be cheaper to do this more intelligently inside
get_relative_path but this method was easier to implement.

Signed-off-by: Mike Crowe <mac at mcrowe.com>
---
 ccache.c |   29 ++++++++++++++++++++++++++---
 1 files changed, 26 insertions(+), 3 deletions(-)

diff --git a/ccache.c b/ccache.c
index 5c88102..a47e980 100644
--- a/ccache.c
+++ b/ccache.c
@@ -433,15 +433,38 @@ ignore:
 static char *
 make_relative_path(char *path)
 {
-	char *relpath;
+	char *relpath1;
+	char *relpath2;
+	char *altpath;
 
 	if (!base_dir || !str_startswith(path, base_dir)) {
 		return path;
 	}
 
-	relpath = get_relative_path(current_working_dir, path);
+	cc_log("make_relative_path: path='%s'", path);
+
+	altpath = x_realpath(path);
+	cc_log("                 altpath='%s'", altpath);
+
+	relpath1 = get_relative_path(current_working_dir, path);
+	cc_log("                relpath1='%s'", relpath1);
 	free(path);
-	return relpath;
+
+	if (altpath) {
+		relpath2 = get_relative_path(current_working_dir, altpath);
+		cc_log("                relpath2='%s'", relpath2);
+		free(altpath);
+	} else {
+		relpath2 = NULL;
+	}
+
+	if (!relpath2 || strlen(relpath1) <= strlen(relpath2)) {
+		free(relpath2);
+		return relpath1;
+	} else {
+		free(relpath1);
+		return relpath2;
+	}
 }
 
 /*
-- 
1.5.6.5