From 34fb5521a5fbb6b95ceff4bbac42a62628bc9f31 Mon Sep 17 00:00:00 2001
From: Behdad Esfahbod <behdad@behdad.org>
Date: Fri, 6 May 2011 00:04:28 -0400
Subject: [PATCH] [API] Add hb_language_get_default()

It uses locale information to detect default language.  It's used by
hb_shape() whenever language is not set on the buffer.

Not sure how to properly test it in the test suite.  Tested by observing
that with DejaVu Sans we select the proper local glyph version for U+431
under Serbian locale.  See http://www.pango.org/ScriptGallery
---
 src/hb-common.cc   | 21 +++++++++++++++++++++
 src/hb-common.h    |  3 +++
 src/hb-shape.cc    |  2 +-
 test/test-common.c |  5 +++++
 4 files changed, 30 insertions(+), 1 deletion(-)

diff --git a/src/hb-common.cc b/src/hb-common.cc
index 49f3eb885..a223edbb3 100644
--- a/src/hb-common.cc
+++ b/src/hb-common.cc
@@ -33,6 +33,8 @@
 #include "hb-mutex-private.hh"
 #include "hb-object-private.hh"
 
+#include <locale.h>
+
 HB_BEGIN_DECLS
 
 
@@ -179,6 +181,25 @@ hb_language_to_string (hb_language_t language)
   return language->s;
 }
 
+hb_language_t
+hb_language_get_default (void)
+{
+  static hb_language_t default_language;
+
+  if (!default_language) {
+    /* This block is not quite threadsafe, but is not as bad as
+     * it looks since it's idempotent.  As long as pointer ops
+     * are atomic, we are safe. */
+
+    /* I hear that setlocale() doesn't honor env vars on Windows,
+     * but for now we ignore that. */
+
+    default_language = hb_language_from_string (setlocale (LC_CTYPE, NULL));
+  }
+
+  return default_language;
+}
+
 
 /* hb_script_t */
 
diff --git a/src/hb-common.h b/src/hb-common.h
index 64109dab2..9546b21c6 100644
--- a/src/hb-common.h
+++ b/src/hb-common.h
@@ -113,6 +113,9 @@ hb_language_from_string (const char *str);
 const char *
 hb_language_to_string (hb_language_t language);
 
+hb_language_t
+hb_language_get_default (void);
+
 
 /* hb_unicode_general_category_t */
 
diff --git a/src/hb-shape.cc b/src/hb-shape.cc
index cc711ea50..fccb81e3b 100644
--- a/src/hb-shape.cc
+++ b/src/hb-shape.cc
@@ -81,7 +81,7 @@ hb_shape (hb_font_t          *font,
   /* If language is not set, use default language from locale */
   if (buffer->props.language == NULL) {
     /* TODO get_default_for_script? using $LANGUAGE */
-    //buffer->props.language = hb_language_get_default ();
+    buffer->props.language = hb_language_get_default ();
   }
 
   hb_shape_internal (font, buffer, features, num_features);
diff --git a/test/test-common.c b/test/test-common.c
index c2b4e1c6d..c1e3175b5 100644
--- a/test/test-common.c
+++ b/test/test-common.c
@@ -169,6 +169,11 @@ test_types_language (void)
 
   g_assert (NULL == hb_language_from_string (NULL));
   g_assert (NULL == hb_language_from_string (""));
+
+  /* Not sure how to test this better.  Setting env vars
+   * here doesn't sound like the right approach, and I'm
+   * not sure that it even works. */
+  g_assert (NULL != hb_language_get_default ());
 }
 
 int