Expose gettext() to client-side JS

This exposes the function set by webhelper.set_gettext() to the client-
side Javascript as a gettext() function, defined on the global window
object. This allows apps to translate messages that are generated
at runtime, not just messages in static HTML.

Some often-used JavaScriptCore operations can be turned into separate
functions, which we can put in a separate source file. This is in
anticipation of the next commit where we will define another function
property of the global object.

[endlessm/eos-sdk#291]

1 files changed, 65 insertions, 0 deletions

diff --git a/webhelper/webextensions/wh2jscutil.c b/webhelper/webextensions/wh2jscutil.c
new file mode 100644
index 0000000..34f325f
--- /dev/null
+++ b/webhelper/webextensions/wh2jscutil.c
@@ -0,0 +1,65 @@
+/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
+
+/* Copyright 2015 Endless Mobile, Inc. */
+
+#include <glib.h>
+#include <JavaScriptCore/JavaScript.h>
+
+#include "wh2jscutil.h"
+
+G_GNUC_INTERNAL
+gboolean
+set_object_property  (JSContextRef         js,
+                      JSObjectRef          object,
+                      const gchar         *property_name,
+                      JSValueRef           property_value,
+                      JSPropertyAttributes flags)
+{
+  JSValueRef exception = NULL;
+  JSStringRef property_name_ref = JSStringCreateWithUTF8CString (property_name);
+  JSObjectSetProperty (js, object, property_name_ref, property_value, flags,
+                       &exception);
+  JSStringRelease (property_name_ref);
+  if (exception != NULL)
+    {
+      g_critical ("There was a problem setting the property '%s'.",
+                  property_name);
+      return FALSE;
+    }
+  return TRUE;
+}
+
+/* Returns a newly allocated string. */
+G_GNUC_INTERNAL
+gchar *
+string_ref_to_string (JSStringRef string_ref)
+{
+  size_t bufsize = JSStringGetMaximumUTF8CStringSize (string_ref);
+  gchar *string = g_new0 (gchar, bufsize);
+  JSStringGetUTF8CString (string_ref, string, bufsize);
+  return string;
+}
+
+G_GNUC_INTERNAL
+JSValueRef
+string_to_value_ref (JSContextRef js,
+                     const gchar *string)
+{
+  JSStringRef string_ref = JSStringCreateWithUTF8CString (string);
+  JSValueRef value_ref = JSValueMakeString (js, string_ref);
+  /* value_ref owns string_ref now */
+  return value_ref;
+}
+
+G_GNUC_INTERNAL
+JSValueRef
+throw_exception (JSContextRef js,
+                 const gchar  *message)
+{
+  JSValueRef msgval = string_to_value_ref (js, message);
+  JSValueRef inner_error = NULL;
+  JSObjectRef exception = JSObjectMakeError (js, 1, &msgval, &inner_error);
+  if (inner_error != NULL)
+    return inner_error;
+  return (JSValueRef) exception;
+}