diff options
Diffstat (limited to 'webhelper/webextensions/wh2extension.c')
| -rw-r--r-- | webhelper/webextensions/wh2extension.c | 524 |
1 files changed, 524 insertions, 0 deletions
diff --git a/webhelper/webextensions/wh2extension.c b/webhelper/webextensions/wh2extension.c new file mode 100644 index 0000000..5b4ad06 --- /dev/null +++ b/webhelper/webextensions/wh2extension.c @@ -0,0 +1,524 @@ +/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */ + +/* Copyright 2015 Endless Mobile, Inc. */ + +#include <math.h> +#include <string.h> + +#include <glib.h> +#include <JavaScriptCore/JavaScript.h> +#include <webkit2/webkit-web-extension.h> +#include <webkitdom/webkitdom.h> + +#include "wh2jscutil.h" + +#define PRIVATE_NAME "_webhelper_private" +#define WH2_DBUS_INTERFACE_NAME "com.endlessm.WebHelper2.Translation" +#define MAIN_PROGRAM_OBJECT_PATH "/com/endlessm/gettext" +#define MAIN_PROGRAM_INTERFACE_NAME "com.endlessm.WebHelper2.Gettext" + +/* Declaration of externally visible symbol */ +void webkit_web_extension_initialize_with_user_data (WebKitWebExtension *, const GVariant *); + +typedef struct { + WebKitWebExtension *extension; /* unowned */ + GDBusConnection *connection; /* unowned */ + GDBusNodeInfo *node; /* owned */ + GDBusInterfaceInfo *interface; /* owned by node */ + GSList *bus_ids; /* GSList<guint>; owned */ + GArray *unregistered_pages; /* GArray<guint64>; owned */ + gchar *main_program_name; /* owned; well-known-name of main program */ +} Context; + +typedef struct { + Context *ctxt; /* unowned */ + guint64 page_id; +} PageContext; + +static const gchar introspection_xml[] = + "<node>" + "<interface name='" WH2_DBUS_INTERFACE_NAME "'>" + "<method name='Translate'/>" + "</interface>" + "</node>"; + +static void +context_free (Context *ctxt) +{ + g_clear_pointer (&ctxt->node, g_dbus_node_info_unref); + g_clear_pointer (&ctxt->bus_ids, g_slist_free); + if (ctxt->unregistered_pages != NULL) + g_array_free (ctxt->unregistered_pages, TRUE); + ctxt->unregistered_pages = NULL; + g_clear_pointer (&ctxt->main_program_name, g_free); + g_free (ctxt); +} + +static gchar * +translation_function (const gchar *message, + Context *ctxt) +{ + GError *error = NULL; + GVariant *result = + g_dbus_connection_call_sync (ctxt->connection, ctxt->main_program_name, + MAIN_PROGRAM_OBJECT_PATH, + MAIN_PROGRAM_INTERFACE_NAME, "Gettext", + g_variant_new ("(s)", message), + (GVariantType *) "(s)", + G_DBUS_CALL_FLAGS_NO_AUTO_START, + -1 /* timeout */, NULL /* cancellable */, + &error); + if (result == NULL) + { + g_warning ("No return value from gettext: %s", error->message); + g_clear_error (&error); + return g_strdup (message); + } + + gchar *retval; + g_variant_get (result, "(s)", &retval); + g_variant_unref (result); + return retval; +} + +static gchar * +ngettext_translation_function (const gchar *singular, + const gchar *plural, + gulong number, + Context *ctxt) +{ + GError *error = NULL; + GVariant *result = + g_dbus_connection_call_sync (ctxt->connection, ctxt->main_program_name, + MAIN_PROGRAM_OBJECT_PATH, + MAIN_PROGRAM_INTERFACE_NAME, "NGettext", + g_variant_new ("(sst)", singular, plural, + number), + (GVariantType *) "(s)", + G_DBUS_CALL_FLAGS_NO_AUTO_START, + -1 /* timeout */, NULL /* cancellable */, + &error); + if (result == NULL) + { + g_warning ("No return value from ngettext: %s", error->message); + g_clear_error (&error); + return g_strdup (number == 1 ? singular : plural); + } + + gchar *retval; + g_variant_get (result, "(s)", &retval); + g_variant_unref (result); + return retval; +} + +static JSValueRef +gettext_shim (JSContextRef js, + JSObjectRef function, + JSObjectRef this_object, + size_t n_args, + const JSValueRef args[], + JSValueRef *exception) +{ + if (n_args != 1) + { + gchar *errmsg = g_strdup_printf ("Expected one argument to gettext()," + "but got %d.", n_args); + *exception = throw_exception (js, errmsg); + g_free (errmsg); + return NULL; + } + if (!JSValueIsString (js, args[0])) + { + *exception = throw_exception (js, + "Expected a string argument to gettext()."); + return NULL; + } + + JSObjectRef window = JSContextGetGlobalObject (js); + JSStringRef private_name = JSStringCreateWithUTF8CString (PRIVATE_NAME); + JSValueRef private_data = JSObjectGetProperty (js, window, private_name, + exception); + if (JSValueIsUndefined (js, private_data)) + return NULL; /* propagate exception */ + Context *ctxt = (Context *) JSObjectGetPrivate ((JSObjectRef) private_data); + + JSStringRef message_ref = JSValueToStringCopy (js, args[0], exception); + if (message_ref == NULL) + return NULL; /* propagate exception */ + gchar *message = string_ref_to_string (message_ref); + JSStringRelease (message_ref); + + gchar *translation = translation_function (message, ctxt); + g_free (message); + + JSValueRef retval = string_to_value_ref (js, translation); + g_free (translation); + return retval; +} + +static JSValueRef +ngettext_shim (JSContextRef js, + JSObjectRef function, + JSObjectRef this_object, + size_t n_args, + const JSValueRef args[], + JSValueRef *exception) +{ + if (n_args != 3) + { + gchar *errmsg = g_strdup_printf ("Expected three arguments to ngettext()," + "but got %d.", n_args); + *exception = throw_exception (js, errmsg); + g_free (errmsg); + return NULL; + } + if (!JSValueIsString (js, args[0])) + { + *exception = throw_exception (js, "The first argument to ngettext() " + "must be a string."); + return NULL; + } + if (!JSValueIsString (js, args[1])) + { + *exception = throw_exception (js, "The second argument to ngettext() " + "must be a string."); + return NULL; + } + if (!JSValueIsNumber (js, args[2])) + { + *exception = throw_exception (js, "The third argument to ngettext() " + "must be a number."); + return NULL; + } + + JSObjectRef window = JSContextGetGlobalObject (js); + JSStringRef private_name = JSStringCreateWithUTF8CString (PRIVATE_NAME); + JSValueRef private_data = JSObjectGetProperty (js, window, private_name, + exception); + if (JSValueIsUndefined (js, private_data)) + return NULL; /* propagate exception */ + Context *ctxt = (Context *) JSObjectGetPrivate ((JSObjectRef) private_data); + + JSStringRef singular_ref = JSValueToStringCopy (js, args[0], exception); + if (singular_ref == NULL) + return NULL; /* propagate exception */ + gchar *singular_msg = string_ref_to_string (singular_ref); + JSStringRelease (singular_ref); + + JSStringRef plural_ref = JSValueToStringCopy (js, args[1], exception); + if (plural_ref == NULL) + { + g_free (singular_msg); + return NULL; /* propagate exception */ + } + gchar *plural_msg = string_ref_to_string (plural_ref); + JSStringRelease (plural_ref); + + double number = JSValueToNumber (js, args[2], exception); + if (isnan (number)) + { + g_free (singular_msg); + g_free (plural_msg); + return NULL; /* propagate exception */ + } + + gchar *translation = ngettext_translation_function (singular_msg, plural_msg, + (gulong) number, ctxt); + g_free (singular_msg); + g_free (plural_msg); + + JSValueRef retval = string_to_value_ref (js, translation); + g_free (translation); + return retval; +} + +static void +translate_html (WebKitDOMDocument *dom, + Context *ctxt) +{ + WebKitDOMNodeList *translatable; + GError *error = NULL; + + translatable = webkit_dom_document_get_elements_by_name (dom, "translatable"); + + gulong index, length = webkit_dom_node_list_get_length (translatable); + for (index = 0; index < length; index++) + { + WebKitDOMNode *element = webkit_dom_node_list_item (translatable, index); + + /* Translate the text */ + if (WEBKIT_DOM_IS_HTML_ELEMENT (element)) + { + WebKitDOMHTMLElement *el_html = WEBKIT_DOM_HTML_ELEMENT (element); + gchar *inner_html = webkit_dom_html_element_get_inner_html (el_html); + gchar *translated_html = translation_function (inner_html, ctxt); + webkit_dom_html_element_set_inner_html (el_html, translated_html, + &error); + if (error != NULL) + { + g_warning ("There was a problem translating '%s' to '%s': %s", + inner_html, translated_html, error->message); + g_clear_error (&error); + } + + g_free (translated_html); + g_free (inner_html); + } + else + { + gchar *text = webkit_dom_node_get_text_content (element); + gchar *translated_text = translation_function (text, ctxt); + webkit_dom_node_set_text_content (element, translated_text, &error); + if (error != NULL) + { + g_warning ("There was a problem translating '%s' to '%s': %s", + text, translated_text, error->message); + g_clear_error (&error); + } + + g_free (translated_text); + g_free (text); + } + } + + g_object_unref (translatable); +} + +static void +on_wh2_method_call (GDBusConnection *connection, + const gchar *sender, + const gchar *object_path, + const gchar *interface_name, + const gchar *method_name, + GVariant *parameters, + GDBusMethodInvocation *invocation, + PageContext *pctxt) +{ + if (strcmp (method_name, "Translate") != 0) + { + g_dbus_method_invocation_return_error (invocation, G_DBUS_ERROR, + G_DBUS_ERROR_UNKNOWN_METHOD, + "Unknown method %s invoked on interface %s", + method_name, interface_name); + return; + } + + WebKitWebPage *page = webkit_web_extension_get_page (pctxt->ctxt->extension, + pctxt->page_id); + if (page == NULL) + return; + /* The page may have been destroyed, but WebKit doesn't let us find out. */ + + WebKitDOMDocument *document = webkit_web_page_get_dom_document (page); + if (document == NULL) + { + g_dbus_method_invocation_return_error_literal (invocation, G_IO_ERROR, + G_IO_ERROR_NOT_INITIALIZED, + "The web page has not loaded a document yet"); + return; + } + + translate_html (document, pctxt->ctxt); + + g_dbus_method_invocation_return_value (invocation, NULL); +} + +static GDBusInterfaceVTable dbus_impl_vtable = { + (GDBusInterfaceMethodCallFunc) on_wh2_method_call, + NULL, /* get property */ + NULL /* set property */ +}; + +static void +register_object (guint64 page_id, + Context *ctxt) +{ + GError *error = NULL; + + g_assert (ctxt->connection != NULL); + + gchar *object_path = g_strdup_printf("/com/endlessm/webview/%" + G_GUINT64_FORMAT, page_id); + + /* This struct is owned by the registered DBus object */ + PageContext *pctxt = g_new0 (PageContext, 1); + pctxt->ctxt = ctxt; + pctxt->page_id = page_id; + + guint bus_id = + g_dbus_connection_register_object (ctxt->connection, object_path, + ctxt->interface, &dbus_impl_vtable, + pctxt, (GDestroyNotify) g_free, &error); + g_free (object_path); + if (bus_id == 0) + { + g_critical ("Failed to export webview object on bus: %s", error->message); + g_clear_error (&error); + goto fail; + } + + ctxt->bus_ids = g_slist_prepend (ctxt->bus_ids, GUINT_TO_POINTER (bus_id)); + return; + +fail: + g_free (pctxt); +} + +static void +on_page_created (WebKitWebExtension *extension, + WebKitWebPage *page, + Context *ctxt) +{ + /* The ID is known to the main process and the web process. So we can address + a specific web page over DBus. */ + guint64 id = webkit_web_page_get_id (page); + + if (ctxt->connection == NULL) + { + /* The connection is not ready yet. Save the page ID in a list of pages + for which we need to register objects later. */ + g_array_append_val (ctxt->unregistered_pages, id); + return; + } + + register_object (id, ctxt); +} + +/* window-object-cleared is the best time to define properties on the page's +window object, according to the documentation. */ +static void +on_window_object_cleared (WebKitScriptWorld *script_world, + WebKitWebPage *page, + WebKitFrame *frame, + Context *ctxt) +{ + JSGlobalContextRef js = + webkit_frame_get_javascript_context_for_script_world (frame, script_world); + JSObjectRef window = JSContextGetGlobalObject (js); + + /* First we need to create a custom class for a private data object to store + our context in, because you can't pass callback data to JavaScriptCore + callbacks. You also can't set private data on a Javascript object if it's not + of a custom class, because the built-in classes don't allocate space for a + private pointer. */ + JSClassDefinition class_def = { + .className = "PrivateContextObject" + }; + JSClassRef klass = JSClassCreate (&class_def); + JSObjectRef private_data = JSObjectMake (js, klass, ctxt); + JSClassRelease (klass); + + if (!set_object_property (js, window, PRIVATE_NAME, (JSValueRef) private_data, + kJSPropertyAttributeReadOnly | kJSPropertyAttributeDontEnum | kJSPropertyAttributeDontDelete)) + return; + + JSObjectRef gettext_func = + JSObjectMakeFunctionWithCallback (js, NULL, gettext_shim); + if (!set_object_property (js, window, "gettext", (JSValueRef) gettext_func, + kJSPropertyAttributeNone)) + return; + + JSObjectRef ngettext_func = + JSObjectMakeFunctionWithCallback (js, NULL, ngettext_shim); + if (!set_object_property (js, window, "ngettext", (JSValueRef) ngettext_func, + kJSPropertyAttributeNone)) + return; +} + +static void +on_bus_acquired (GDBusConnection *connection, + const gchar *name, + Context *ctxt) +{ + GError *error = NULL; + + ctxt->connection = connection; + + /* Get a notification when Javascript is ready */ + WebKitScriptWorld *script_world = webkit_script_world_get_default (); + g_signal_connect (script_world, "window-object-cleared", + G_CALLBACK (on_window_object_cleared), ctxt); + + /* Export our interface on the bus */ + ctxt->node = g_dbus_node_info_new_for_xml (introspection_xml, &error); + if (ctxt->node == NULL) + goto fail; + ctxt->interface = g_dbus_node_info_lookup_interface (ctxt->node, + WH2_DBUS_INTERFACE_NAME); + if (ctxt->interface == NULL) + goto fail; + + /* Register DBus objects for any pages that were created before we got here */ + guint ix; + for (ix = 0; ix < ctxt->unregistered_pages->len; ix++) + { + guint64 id = g_array_index (ctxt->unregistered_pages, guint64, ix); + register_object (id, ctxt); + } + g_array_remove_range (ctxt->unregistered_pages, 0, + ctxt->unregistered_pages->len); + + return; + +fail: + if (error != NULL) + { + g_critical ("Error hooking up web extension DBus interface: %s", + error->message); + g_clear_error (&error); + } + else + { + g_critical ("Unknown error hooking up web extension DBus interface"); + } +} + +static void +unregister_object (gpointer data, + GDBusConnection *connection) +{ + guint bus_id = GPOINTER_TO_UINT (data); + if (!g_dbus_connection_unregister_object (connection, bus_id)) + g_critical ("Trouble unregistering object"); +} + +static void +on_name_lost (GDBusConnection *connection, + const gchar *name, + Context *ctxt) +{ + if (connection == NULL) + { + g_warning ("Could not initialize DBus interface for WebHelper2 " + "extension; the name %s was lost.", name); + return; + } + + g_slist_foreach (ctxt->bus_ids, (GFunc) unregister_object, connection); +} + +/* Receives the main program's unique DBus name as user data. */ +G_MODULE_EXPORT void +webkit_web_extension_initialize_with_user_data (WebKitWebExtension *extension, + const GVariant *data_from_app) +{ + const gchar *name = g_variant_get_string ((GVariant *) data_from_app, NULL); + + Context *ctxt = g_new0 (Context, 1); + ctxt->extension = extension; + ctxt->unregistered_pages = g_array_new (FALSE, FALSE, sizeof (guint64)); + ctxt->main_program_name = g_strdup (name); + gchar *well_known_name = g_strconcat (name, ".webhelper", NULL); + + g_signal_connect (extension, "page-created", + G_CALLBACK (on_page_created), ctxt); + + g_bus_own_name (G_BUS_TYPE_SESSION, well_known_name, + G_BUS_NAME_OWNER_FLAGS_NONE, + (GBusAcquiredCallback) on_bus_acquired, + NULL, /* name acquired callback */ + (GBusNameLostCallback) on_name_lost, + ctxt, (GDestroyNotify) context_free); + + g_free (well_known_name); +} |