[gtksourceview] Allow passing empty strings to gtk_source_language_manager_guess_language.

[Ignacio Casal Quinteiro <icq src gnome org>]

commit abff91f277d34c869cfebc2e14562e6ef024dd79
Author: Krzesimir Nowak <qdlacz gmail com>
Date:   Thu Jul 15 22:59:32 2010 +0200

    Allow passing empty strings to gtk_source_language_manager_guess_language.
    
    Also added tests checking this change.

 gtksourceview/gtksourcelanguagemanager.c |    7 +++----
 tests/test-languagemanager.c             |   30 ++++++++++++++++++++++++++++++
 2 files changed, 33 insertions(+), 4 deletions(-)
---
diff --git a/gtksourceview/gtksourcelanguagemanager.c b/gtksourceview/gtksourcelanguagemanager.c
index 4b68c05..1d86bca 100644
--- a/gtksourceview/gtksourcelanguagemanager.c
+++ b/gtksourceview/gtksourcelanguagemanager.c
@@ -625,9 +625,8 @@ gtk_source_language_manager_guess_language (GtkSourceLanguageManager *lm,
 	GSList *langs = NULL;
 
 	g_return_val_if_fail (GTK_IS_SOURCE_LANGUAGE_MANAGER (lm), NULL);
-	g_return_val_if_fail (filename != NULL || content_type != NULL, NULL);
-	g_return_val_if_fail ((filename == NULL || *filename != 0) &&
-			      (content_type == NULL || *content_type != 0), NULL);
+	g_return_val_if_fail ((filename != NULL && *filename != '\0') ||
+	                      (content_type != NULL && *content_type != '\0'), NULL);
 
 	ensure_languages (lm);
 
@@ -638,7 +637,7 @@ gtk_source_language_manager_guess_language (GtkSourceLanguageManager *lm,
 	  - no glob matches
 	*/
 
-	if (filename != NULL)
+	if (filename != NULL && *filename != '\0')
 		langs = pick_langs_for_filename (lm, filename);
 
 	if (langs != NULL)
diff --git a/tests/test-languagemanager.c b/tests/test-languagemanager.c
index 1d3c04d..3c92a1f 100644
--- a/tests/test-languagemanager.c
+++ b/tests/test-languagemanager.c
@@ -55,18 +55,48 @@ test_guess_language (void)
 	}
 	g_test_trap_assert_failed ();
 
+	if (g_test_trap_fork (0, G_TEST_TRAP_SILENCE_STDERR))
+	{
+		l = gtk_source_language_manager_guess_language (lm, "", NULL);
+	}
+	g_test_trap_assert_failed ();
+
+	if (g_test_trap_fork (0, G_TEST_TRAP_SILENCE_STDERR))
+	{
+		l = gtk_source_language_manager_guess_language (lm, NULL, "");
+	}
+	g_test_trap_assert_failed ();
+
+	if (g_test_trap_fork (0, G_TEST_TRAP_SILENCE_STDERR))
+	{
+		l = gtk_source_language_manager_guess_language (lm, "", "");
+	}
+	g_test_trap_assert_failed ();
+
 	l = gtk_source_language_manager_guess_language (lm, "foo.abcdef", NULL);
 	g_assert (l == NULL);
 
+	l = gtk_source_language_manager_guess_language (lm, "foo.abcdef", "");
+	g_assert (l == NULL);
+
 	l = gtk_source_language_manager_guess_language (lm, NULL, "image/png");
 	g_assert (l == NULL);
 
+	l = gtk_source_language_manager_guess_language (lm, "", "image/png");
+	g_assert (l == NULL);
+
 	l = gtk_source_language_manager_guess_language (lm, "foo.c", NULL);
 	g_assert_cmpstr (gtk_source_language_get_id (l), ==, "c");
 
+	l = gtk_source_language_manager_guess_language (lm, "foo.c", "");
+	g_assert_cmpstr (gtk_source_language_get_id (l), ==, "c");
+
 	l = gtk_source_language_manager_guess_language (lm, NULL, "text/x-csrc");
 	g_assert_cmpstr (gtk_source_language_get_id (l), ==, "c");
 
+	l = gtk_source_language_manager_guess_language (lm, "", "text/x-csrc");
+	g_assert_cmpstr (gtk_source_language_get_id (l), ==, "c");
+
 	l = gtk_source_language_manager_guess_language (lm, "foo.c", "text/x-csrc");
 	g_assert_cmpstr (gtk_source_language_get_id (l), ==, "c");