From 331328223912b66dd25d5cb6ed250d67419d54de Mon Sep 17 00:00:00 2001

From: Michal Schmidt <mschmidt@redhat.com>

Date: Mon, 16 Mar 2015 21:58:35 +0100

Subject: [PATCH] shared: add path_compare(), an ordering path comparison

... and make path_equal() a simple wrapper around it.

(cherry picked from commit 2230852bd9755e1b7bfd1260082471f559b0a005)

---

 src/shared/path-util.c    | 37 +++++++++++++++++++++++++++----------

 src/shared/path-util.h    |  1 +

 src/test/test-path-util.c | 36 +++++++++++++++++++++++++-----------

 3 files changed, 53 insertions(+), 21 deletions(-)

diff --git a/src/shared/path-util.c b/src/shared/path-util.c

index 70bc1ca..d5510bf 100644

--- a/src/shared/path-util.c

+++ b/src/shared/path-util.c

@@ -403,12 +403,18 @@ char* path_startswith(const char *path, const char *prefix) {

         }

 }

-bool path_equal(const char *a, const char *b) {

+int path_compare(const char *a, const char *b) {

+        int d;

+

         assert(a);

         assert(b);

-        if ((a[0] == '/') != (b[0] == '/'))

-                return false;

+        /* A relative path and an abolute path must not compare as equal.

+         * Which one is sorted before the other does not really matter.

+         * Here a relative path is ordered before an absolute path. */

+        d = (a[0] == '/') - (b[0] == '/');

+        if (d)

+                return d;

         for (;;) {

                 size_t j, k;

@@ -417,25 +423,36 @@ bool path_equal(const char *a, const char *b) {

                 b += strspn(b, "/");

                 if (*a == 0 && *b == 0)

-                        return true;

+                        return 0;

-                if (*a == 0 || *b == 0)

-                        return false;

+                /* Order prefixes first: "/foo" before "/foo/bar" */

+                if (*a == 0)

+                        return -1;

+                if (*b == 0)

+                        return 1;

                 j = strcspn(a, "/");

                 k = strcspn(b, "/");

-                if (j != k)

-                        return false;

+                /* Alphabetical sort: "/foo/aaa" before "/foo/b" */

+                d = memcmp(a, b, MIN(j, k));

+                if (d)

+                        return (d > 0) - (d < 0); /* sign of d */

-                if (memcmp(a, b, j) != 0)

-                        return false;

+                /* Sort "/foo/a" before "/foo/aaa" */

+                d = (j > k) - (j < k);  /* sign of (j - k) */

+                if (d)

+                        return d;

                 a += j;

                 b += k;

         }

 }

+bool path_equal(const char *a, const char *b) {

+        return path_compare(a, b) == 0;

+}

+

 bool path_equal_or_files_same(const char *a, const char *b) {

         return path_equal(a, b) || files_same(a, b) > 0;

 }

diff --git a/src/shared/path-util.h b/src/shared/path-util.h

index bcf116e..ca81b49 100644

--- a/src/shared/path-util.h

+++ b/src/shared/path-util.h

@@ -44,6 +44,7 @@ char* path_make_absolute_cwd(const char *p);

 int path_make_relative(const char *from_dir, const char *to_path, char **_r);

 char* path_kill_slashes(char *path);

 char* path_startswith(const char *path, const char *prefix) _pure_;

+int path_compare(const char *a, const char *b) _pure_;

 bool path_equal(const char *a, const char *b) _pure_;

 bool path_equal_or_files_same(const char *a, const char *b);

 char* path_join(const char *root, const char *path, const char *rest);

diff --git a/src/test/test-path-util.c b/src/test/test-path-util.c

index 11aa52a..6396fcb 100644

--- a/src/test/test-path-util.c

+++ b/src/test/test-path-util.c

@@ -27,23 +27,37 @@

 #include "macro.h"

 #include "strv.h"

+#define test_path_compare(a, b, result) {                 \

+                assert_se(path_compare(a, b) == result);  \

+                assert_se(path_compare(b, a) == -result); \

+                assert_se(path_equal(a, b) == !result);   \

+                assert_se(path_equal(b, a) == !result);   \

+        }

 static void test_path(void) {

-        assert_se(path_equal("/goo", "/goo"));

-        assert_se(path_equal("//goo", "/goo"));

-        assert_se(path_equal("//goo/////", "/goo"));

-        assert_se(path_equal("goo/////", "goo"));

+        test_path_compare("/goo", "/goo", 0);

+        test_path_compare("/goo", "/goo", 0);

+        test_path_compare("//goo", "/goo", 0);

+        test_path_compare("//goo/////", "/goo", 0);

+        test_path_compare("goo/////", "goo", 0);

+

+        test_path_compare("/goo/boo", "/goo//boo", 0);

+        test_path_compare("//goo/boo", "/goo/boo//", 0);

-        assert_se(path_equal("/goo/boo", "/goo//boo"));

-        assert_se(path_equal("//goo/boo", "/goo/boo//"));

+        test_path_compare("/", "///", 0);

-        assert_se(path_equal("/", "///"));

+        test_path_compare("/x", "x/", 1);

+        test_path_compare("x/", "/", -1);

-        assert_se(!path_equal("/x", "x/"));

-        assert_se(!path_equal("x/", "/"));

+        test_path_compare("/x/./y", "x/y", 1);

+        test_path_compare("x/.y", "x/y", -1);

-        assert_se(!path_equal("/x/./y", "x/y"));

-        assert_se(!path_equal("x/.y", "x/y"));

+        test_path_compare("foo", "/foo", -1);

+        test_path_compare("/foo", "/foo/bar", -1);

+        test_path_compare("/foo/aaa", "/foo/b", -1);

+        test_path_compare("/foo/aaa", "/foo/b/a", -1);

+        test_path_compare("/foo/a", "/foo/aaa", -1);

+        test_path_compare("/foo/a/b", "/foo/aaa", -1);

         assert_se(path_is_absolute("/"));

         assert_se(!path_is_absolute("./"));