From e49872433921fdf6b22deef70f9532310a640114 Mon Sep 17 00:00:00 2001
From: Richard Hughes <richard@hughsie.com>
Date: Sun, 29 Apr 2018 19:18:58 +0100
Subject: Follow the Debian tilde usage when ordering versions

Debian requires a custom version of strcmp for the version comparison where
tilde is apparently the worst-of-the-worst when checking version segments.

Fixes https://github.com/hughsie/appstream-glib/issues/234
---
 libappstream-glib/as-self-test.c |  6 ++++++
 libappstream-glib/as-utils.c     | 26 +++++++++++++++++++++++++-
 2 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/libappstream-glib/as-self-test.c b/libappstream-glib/as-self-test.c
index 3c85a12..c7b4832 100644
--- a/libappstream-glib/as-self-test.c
+++ b/libappstream-glib/as-self-test.c
@@ -5102,6 +5102,12 @@ as_test_utils_vercmp_func (void)
 	g_assert_cmpint (as_utils_vercmp ("1.2a.3", "1.2b.3"), <, 0);
 	g_assert_cmpint (as_utils_vercmp ("1.2b.3", "1.2a.3"), >, 0);
 
+	/* tilde is all-powerful */
+	g_assert_cmpint (as_utils_vercmp ("1.2.3~rc1", "1.2.3~rc1"), ==, 0);
+	g_assert_cmpint (as_utils_vercmp ("1.2.3~rc1", "1.2.3"), <, 0);
+	g_assert_cmpint (as_utils_vercmp ("1.2.3", "1.2.3~rc1"), >, 0);
+	g_assert_cmpint (as_utils_vercmp ("1.2.3~rc2", "1.2.3~rc1"), >, 0);
+
 	/* invalid */
 	g_assert_cmpint (as_utils_vercmp ("1", NULL), ==, G_MAXINT);
 	g_assert_cmpint (as_utils_vercmp (NULL, "1"), ==, G_MAXINT);
diff --git a/libappstream-glib/as-utils.c b/libappstream-glib/as-utils.c
index c605cd1..83af4a4 100644
--- a/libappstream-glib/as-utils.c
+++ b/libappstream-glib/as-utils.c
@@ -1353,6 +1353,30 @@ as_utils_search_tokenize (const gchar *search)
 	return values;
 }
 
+static gint8
+as_utils_vercmp_char (gchar chr1, gchar chr2)
+{
+	if (chr1 == chr2)
+		return 0;
+	if (chr1 == '~')
+		return -127;
+	if (chr2 == '~')
+		return 127;
+	return chr1 - chr2;
+}
+
+static gint
+as_utils_vercmp_chunk (const gchar *str1, const gchar *str2)
+{
+	guint i;
+	for (i = 0; str1[i] != '\0' && str2[i] != '\0'; i++) {
+		gint rc = as_utils_vercmp_char (str1[i], str2[i]);
+		if (rc != 0)
+			return rc;
+	}
+	return as_utils_vercmp_char (str1[i], str2[i]);
+}
+
 /**
  * as_utils_vercmp:
  * @version_a: the release version, e.g. 1.2.3
@@ -1411,7 +1435,7 @@ as_utils_vercmp (const gchar *version_a, const gchar *version_b)
 		/* compare strings */
 		if ((endptr_a != NULL && endptr_a[0] != '\0') ||
 		    (endptr_b != NULL && endptr_b[0] != '\0')) {
-			gint rc = g_strcmp0 (endptr_a, endptr_b);
+			gint rc = as_utils_vercmp_chunk (endptr_a, endptr_b);
 			if (rc < 0)
 				return -1;
 			if (rc > 0)
-- 
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