library.webkitgtk_extension.c Maven / Gradle / Ivy
#include "webkitgtk_extension.h"
/**
* Note: g_asserts() are active/working. (i.e not dissabled)
*/
// +-------------+----------------------------------------------------------------
// | Misc Globals|
// +-------------+
gint32 parentUniqueId = 0;
// see: WebKitGTK.java 'TYPE NOTES'
guchar SWT_DBUS_MAGIC_NUMBER_EMPTY_ARRAY = 101;
guchar SWT_DBUS_MAGIC_NUMBER_NULL = 48;
// +-------------+----------------------------------------------------------------
// | Misc Helpers|
// +-------------+
/* Combine String and int.
* @return char * should be free()'ed.
*/
char * combineStrInt(char * in_str, gint32 in_i) {
int new_str_len = strlen(in_str) + snprintf(NULL, 0, "%d", in_i) + 1; // str + int + \0
char * out_str = malloc (new_str_len);
snprintf( out_str, new_str_len, "%s%d", in_str, in_i);
return out_str;
}
// +-------------+----------------------------------------------------------------
// | GDBus logic |
// +-------------+
static const gchar base_service_name[] = "org.eclipse.swt"; // Base name. Full name has uniqueID appended.
static const gchar object_name[] = "/org/eclipse/swt/gdbus";
static const gchar interface[] = "org.eclipse.swt.gdbusInterface";
typedef struct {
guint64 page_id;
const gchar *function;
const gchar *url;
} BrowserFunction;
GSList *function_list = NULL;
GDBusProxy *proxy = NULL; // The proxy that we work with
void proxy_init () {
g_assert(parentUniqueId != 0);
if (proxy != NULL) { // Already initialized.
return;
}
const char * full_service_name = combineStrInt((char *) base_service_name, parentUniqueId);
GError *error = NULL; // Some functions return errors through params
// g_type_init(); // Not needed as of glib 2.36
proxy = g_dbus_proxy_new_for_bus_sync(G_BUS_TYPE_SESSION, G_DBUS_PROXY_FLAGS_NONE, NULL, full_service_name, object_name, interface, NULL, &error);
if ((proxy == NULL) || (error != NULL)) {
fprintf(stderr, "SWT Webextension: GDBus setupServer error. Could not connect to %s:%s on %s.\n", full_service_name, object_name, interface);
if (error != NULL) {
fprintf(stderr, " %s\n", error->message);
}
exit(0);
}
}
/**
* Caller should free the returned GVariant *.
*/
GVariant * callMainProc(char * methodName, GVariant * params) {
proxy_init();
GError *error = NULL; // Some functions return errors through params
GVariant *result; // The value result from a call
// Send a message
result = g_dbus_proxy_call_sync(proxy, methodName, params, 0, -1, NULL, &error); // You can make multiple calls
// Error checking.
if (result == NULL) {
if (error != NULL) {
g_error("SWT web extension: Call failed because '%s.'\n", error->message);
}
else {
g_error("SWT web extension: Call failed for an unknown reason.\n");
}
return NULL;
}
// Deal with result
return result;
}
// +--------------------------------------------------+-------------------------------------
// | JavaScriptCore to/from conversion GVariant logic |
// +--------------------------------------------------+
/** Return true if the given JSValueRef is one we can push over gdbus. False otherwise.
* We support basic types, nulls and arrays of basic types.*/
gboolean is_js_valid(JSContextRef context, JSValueRef value) {
JSType type = JSValueGetType(context, value);
if (type == kJSTypeBoolean
|| type == kJSTypeNumber
|| type == kJSTypeString
|| type == kJSTypeNull
|| type == kJSTypeUndefined) {
return true;
}
if (type == kJSTypeObject && JSValueIsArray(context, value)) {
JSStringRef propertyName = JSStringCreateWithUTF8CString("length");
JSObjectRef object = JSValueToObject(context, value, NULL);
JSValueRef valuePtr = JSObjectGetProperty(context, object, propertyName, NULL);
JSStringRelease(propertyName);
int length = (int) JSValueToNumber(context, valuePtr, NULL);
int i;
for (i = 0; i < length; i++) {
const JSValueRef child = JSObjectGetPropertyAtIndex(context, object, i, NULL);
if (!is_js_valid(context, child)) {
return false;
}
}
return true;
}
return false;
}
/*
* Developer note:
* JavaScriptCore defines a "Number" to be a double in general. It doesn't seem to be using "Int".
*/
static GVariant * convert_js_to_gvariant (JSContextRef context, JSValueRef value){
g_assert(context != NULL);
g_assert(value != NULL);
JSType type = JSValueGetType(context, value);
if (type == kJSTypeBoolean) {
gboolean result = JSValueToNumber(context, value, NULL) != 0;
return g_variant_new_boolean(result);
}
if (type == kJSTypeNumber) {
double result = JSValueToNumber(context, value, NULL);
return g_variant_new_double(result);
}
if (type == kJSTypeString) {
JSStringRef stringRef = JSValueToStringCopy(context, value, NULL);
size_t length = JSStringGetMaximumUTF8CStringSize(stringRef);
char* string = (char*) malloc(length);
JSStringGetUTF8CString(stringRef, string, length);
GVariant *variant = g_variant_new_string(string);
free(string);
return variant;
}
if (type == kJSTypeNull || type == kJSTypeUndefined) {
return g_variant_new_byte(SWT_DBUS_MAGIC_NUMBER_NULL);
}
if (type == kJSTypeObject) {
JSStringRef propertyName = JSStringCreateWithUTF8CString("length");
JSObjectRef object = JSValueToObject(context, value, NULL);
JSValueRef valuePtr = JSObjectGetProperty(context, object, propertyName, NULL);
JSStringRelease(propertyName);
if (JSValueGetType(context, valuePtr) == kJSTypeNumber) {
int length = (int) JSValueToNumber(context, valuePtr, NULL);
if (length == 0) {
return g_variant_new_byte(SWT_DBUS_MAGIC_NUMBER_EMPTY_ARRAY);
}
GVariant **children = g_new(GVariant *, length);
int i = 0;
for (i = 0; i < length; i++) {
const JSValueRef child = JSObjectGetPropertyAtIndex(context, object, i, NULL);
children[i] = convert_js_to_gvariant(context, child);
}
GVariant* variant = g_variant_new_tuple(children, length);
g_free(children);
return variant;
}
}
// Get type value string
JSStringRef valueIString = JSValueToStringCopy(context, value, NULL);
size_t valueUTF8Size = JSStringGetMaximumUTF8CStringSize(valueIString);
char* valueUTF8 = (char*) malloc(valueUTF8Size);
JSStringGetUTF8CString(valueIString, valueUTF8, valueUTF8Size);
g_warning("SWT Webextension: Unhandled type %d value: %s \n", type, valueUTF8);
free(valueUTF8);
JSStringRelease(valueIString);
return NULL;
}
static JSValueRef convert_gvariant_to_js (JSContextRef context, GVariant * value){
g_assert(context != NULL);
g_assert(value != NULL);
if (g_variant_is_of_type(value, G_VARIANT_TYPE_BYTE)) { // see: WebKitGTK.java 'TYPE NOTES'
guchar magic_number = g_variant_get_byte(value);
if (magic_number == SWT_DBUS_MAGIC_NUMBER_NULL) {
// 'JSValueMakeUndefined' is used as oppose to 'JSValueMakeNull' (from what I gather) for legacy reasons.
// I.e webkit1 used it, so we shall use it in webkit2 also.
return JSValueMakeUndefined(context);
} else if (magic_number == SWT_DBUS_MAGIC_NUMBER_EMPTY_ARRAY) {
return JSObjectMakeArray(context, 0, NULL, NULL); // The empty array with no children.
} else {
g_error("Java sent an unknown magic number: '%d' , this should never happen. \n", magic_number);
}
}
if (g_variant_is_of_type(value, G_VARIANT_TYPE_BOOLEAN)) {
return JSValueMakeBoolean(context, g_variant_get_boolean(value));
}
if (g_variant_is_of_type(value, G_VARIANT_TYPE_DOUBLE)) {
return JSValueMakeNumber(context, g_variant_get_double(value));
}
if (g_variant_is_of_type(value, G_VARIANT_TYPE_STRING)) {
JSStringRef stringRef = JSStringCreateWithUTF8CString(g_variant_get_string(value, NULL));
JSValueRef result = JSValueMakeString(context, stringRef);
JSStringRelease(stringRef);
return result;
}
if (g_variant_is_of_type(value, G_VARIANT_TYPE_TUPLE)) {
gsize length = (int) g_variant_n_children(value);
JSValueRef *children = g_new(JSValueRef, length);
int i = 0;
for (i = 0; i < length; i++) {
children[i] = convert_gvariant_to_js(context, g_variant_get_child_value(value, i));
}
JSValueRef result = JSObjectMakeArray(context, length, children, NULL);
g_free(children);
return result;
}
g_error("Unhandled type %s \n", g_variant_get_type_string(value));
return NULL;
}
// +--------------------+---------------------------------------------------------
// | WebExtension Logic |
// +--------------------+
// Reached by calling "webkit2callJava();" in javascript console.
// Some basic c function to be exposed to the javascript environment
static JSValueRef webkit2callJava (JSContextRef context,
JSObjectRef function,
JSObjectRef thisObject,
size_t argumentCount,
const JSValueRef arguments[], // [String webview, double index, String Token, Object[] args]
JSValueRef *exception) {
g_assert (argumentCount == 4);
GVariant *g_var_params; // The parameters to a function call
// Need to ensure user arguments won't break gdbus.
if (!is_js_valid(context, arguments[3])) {
g_warning("SWT Webextension: Arguments contain an invalid type (object). Only Number,Boolean,null,String and (mixed) arrays of basic types are supported");
return 0;
}
g_var_params = g_variant_new ("(@s@d@s@*)", // pointer to String, pointer to double, pointer to string, pointer to any type.
convert_js_to_gvariant(context, arguments[0]), // String webView
convert_js_to_gvariant(context, arguments[1]), // int index
convert_js_to_gvariant(context, arguments[2]), // String Token
convert_js_to_gvariant(context, arguments[3]) // js args
);
GVariant *g_var_result = callMainProc("webkit2callJava", g_var_params);
if (g_var_result == NULL) {
g_error("SWT Webextension: Java call returned NULL. This should never happpen\n");
return 0;
}
// gdbus dynamic call always returns an array(tuple) with return types.
// In our case, we return a single type or an array.
// E.g java:int -> gdbus:(i) (array containing one int)
// E.g java [int,str] -> gdbus:((is)) (array with array of (int+str).
// So we always extract the first child, convert and pass to js.
JSValueRef retVal = 0;
if (g_variant_is_of_type(g_var_result, G_VARIANT_TYPE_TUPLE)) {
if (g_variant_n_children(g_var_result) != 1) {
g_error("Should only receive a single item in the tuple, but length is: %ud\n", (unsigned int) g_variant_n_children(g_var_result));
}
retVal = convert_gvariant_to_js(context, g_variant_get_child_value(g_var_result, 0));
} else {
g_error("SWT Webextension: Unsupported return type. Should be an array, but received a single type.\n");
}
g_variant_unref(g_var_result);
return retVal;
}
static void web_page_created_callback(WebKitWebExtension *extension, WebKitWebPage *web_page, gpointer user_data) {
// Observation. This seems to be called only once.
}
/**
* Returns the main frame of the WebPage with the given ID
*/
static WebKitFrame *webkitgtk_extension_get_main_frame (const guint64 id) {
WebKitWebPage *web_page = webkit_web_extension_get_page (this_extension, id);
return webkit_web_page_get_main_frame (web_page);
}
/*
* Execute the Javascript for the given page and URL.
*/
static gboolean webkitgtk_extension_execute_script (const guint64 page_id, const gchar* script, const gchar* url) {
WebKitFrame *main_frame = webkitgtk_extension_get_main_frame (page_id);
JSStringRef url_string = JSStringCreateWithUTF8CString (url);
JSStringRef script_string = JSStringCreateWithUTF8CString (script);
JSGlobalContextRef context = webkit_frame_get_javascript_global_context (main_frame);
JSValueRef exception;
JSValueRef result = JSEvaluateScript(context, script_string, NULL, url_string, 0, &exception);
if (!result) {
JSStringRef exceptionIString = JSValueToStringCopy(context, exception, NULL);
size_t exceptionUTF8Size = JSStringGetMaximumUTF8CStringSize(exceptionIString);
char* exceptionUTF8 = (char*)malloc(exceptionUTF8Size);
JSStringGetUTF8CString(exceptionIString, exceptionUTF8, exceptionUTF8Size);
g_error("SWT web extension: failed to execute script exception: %s\n", exceptionUTF8);
free(exceptionUTF8);
JSStringRelease(exceptionIString);
}
JSStringRelease (url_string);
JSStringRelease (script_string);
return result != NULL;
}
void execute_browser_functions(gconstpointer item, gpointer page) {
BrowserFunction *function = (BrowserFunction *) item;
if (function != NULL && function->page_id == GPOINTER_TO_UINT(page)) {
webkitgtk_extension_execute_script(function->page_id, function->function, function->url);
}
return;
}
gint find_browser_function (gconstpointer item, gconstpointer target) {
BrowserFunction *element = (BrowserFunction *) item;
BrowserFunction *remove = (BrowserFunction *) target;
if (element->page_id == remove->page_id && g_strcmp0(element->function, remove->function) == 0 &&
g_strcmp0(element->url, remove->url) == 0) {
return 0;
}
return 1;
}
void add_browser_function(guint64 page_id, const gchar *function, const gchar *url) {
BrowserFunction *func = g_slice_new0(BrowserFunction);
func->page_id = page_id;
func->function = function;
func->url = url;
function_list = g_slist_append(function_list, func);
}
void remove_browser_function(guint64 page_id, const gchar *function, const gchar *url) {
BrowserFunction *func = g_slice_new0(BrowserFunction);
func->page_id = page_id;
func->function = function;
func->url = url;
GSList *to_remove = g_slist_find_custom(function_list, func, find_browser_function);
if (to_remove != NULL) {
function_list = g_slist_delete_link(function_list, to_remove);
}
g_slice_free(BrowserFunction, func);
}
void unpack_browser_function_array(GVariant *array) {
GVariantIter iter;
GVariant *child;
g_variant_iter_init (&iter, array);
while ((child = g_variant_iter_next_value (&iter))) {
gsize length = (int)g_variant_n_children (child);
if (length > 3) {
// If the length is longer than three, something went wrong and this tuple should be skipped
g_warning("SWT web extension: there was an error unpacking the GVariant tuple for a BrowserFunction in the web extension.\n");
continue;
}
guint64 page = g_variant_get_uint64(g_variant_get_child_value(child, 0));
if (page == -1) {
// Empty or malformed BrowserFunction, skip this one
continue;
} else {
const gchar *function = g_variant_get_string(g_variant_get_child_value(child, 1), NULL);
const gchar *url = g_variant_get_string(g_variant_get_child_value(child, 2), NULL);
if (function != NULL && url != NULL) {
add_browser_function(page, function, url);
} else {
g_warning("SWT web extension: there was an error unpacking the function string or URL.\n");
}
}
g_variant_unref (child);
}
}
/*
* Every time a webpage is loaded, we should re-register the 'webkit2callJava' function.
* Additionally, we re-register all BrowserFunctions that are stored in the function_list
* GSList.
*/
static void window_object_cleared_callback (WebKitScriptWorld *world, WebKitWebPage *web_page,
WebKitFrame *frame,
gpointer user_data) {
// Observation: This is called every time a webpage is loaded.
JSGlobalContextRef jsContext;
JSObjectRef globalObject;
JSValueRef exception = 0;
jsContext = webkit_frame_get_javascript_context_for_script_world (frame, world);
globalObject = JSContextGetGlobalObject (jsContext);
JSStringRef function_name = JSStringCreateWithUTF8CString("webkit2callJava"); // Func reference by javascript
JSObjectRef jsFunction = JSObjectMakeFunctionWithCallback(jsContext, function_name, webkit2callJava); // C reference to func
JSObjectSetProperty(jsContext, globalObject, function_name, jsFunction,
kJSPropertyAttributeDontDelete | kJSPropertyAttributeReadOnly, &exception);
if (exception) {
g_print("OJSObjectSetProperty exception occurred");
}
/*
* Iterate over the list of BrowserFunctions and execute each one of them for the current page.
* This ensures that BrowserFunctions are not lost on page reloads. See bug 536141.
*/
if (function_list != NULL) {
guint64 page_id = webkit_web_page_get_id (web_page);
if (page_id != -1) {
g_slist_foreach(function_list, (GFunc)execute_browser_functions, GUINT_TO_POINTER(page_id));
} else {
g_warning("SWT web extension: there was an error fetching the page ID in the object_cleared callback.\n");
}
}
}
static void
webkitgtk_extension_handle_method_call (GDBusConnection *connection, const gchar *sender,
const gchar *object_path,
const gchar *interface_name,
const gchar *method_name,
GVariant *parameters,
GDBusMethodInvocation *invocation,
gpointer user_data) {
gboolean result = FALSE;
const gchar *script;
const gchar *url;
guint64 page_id;
// Check method names
if (g_strcmp0(method_name, "webkitgtk_extension_register_function") == 0) {
g_variant_get(parameters, "(t&s&s)", &page_id, &script, &url);
if (page_id != -1) {
result = TRUE;
// Return before processing the linked list, to prevent DBus from hanging
g_dbus_method_invocation_return_value(invocation, g_variant_new("(b)", result));
add_browser_function(page_id, script, url);
return;
}
g_dbus_method_invocation_return_value(invocation, g_variant_new("(b)", result));
return;
}
if (g_strcmp0(method_name, "webkitgtk_extension_deregister_function") == 0) {
g_variant_get(parameters, "(t&s&s)", &page_id, &script, &url);
if (page_id != -1) {
result = TRUE;
// Return before processing the linked list, to prevent DBus from hanging
g_dbus_method_invocation_return_value(invocation, g_variant_new("(b)", result));
remove_browser_function(page_id, script, url);
return;
}
g_dbus_method_invocation_return_value(invocation, g_variant_new("(b)", result));
return;
}
g_error ("UNKNOWN method %s\n", method_name);
}
static const GDBusInterfaceVTable interface_vtable = {webkitgtk_extension_handle_method_call, NULL, NULL};
static void on_bus_acquired (GDBusConnection *connection, const gchar *name, gpointer user_data) {
dbus_interface = g_dbus_node_info_lookup_interface(dbus_node, WEBKITGTK_EXTENSION_DBUS_INTERFACE);
guint registration_id = g_dbus_connection_register_object(connection,
webkitgtk_extension_dbus_path,
dbus_interface,
&interface_vtable, NULL, /* user_data */
NULL, /* user_data_free_func */
NULL); /* GError** */
g_assert(registration_id > 0);
GVariant *g_var_result = callMainProc("webkitWebExtensionIdentifer", g_variant_new ("(ss)",
webkitgtk_extension_dbus_name, webkitgtk_extension_dbus_path));
if (g_variant_is_of_type(g_var_result, G_VARIANT_TYPE_TUPLE)) {
unpack_browser_function_array(g_variant_get_child_value(g_var_result, 0));
} else {
g_warning("SWT web extension: on_bus_acquired return value from SWT was an unexpected type (not a tuple).\n");
}
return;
}
G_MODULE_EXPORT void webkit_web_extension_initialize_with_user_data(WebKitWebExtension *extension, GVariant *user_data) {
// To debug this extension:
// - ensure this is build with debug flags (look for '-g*' in make_linux, or 'SWT_LIB_DEBUG' macro.
// - connect to WebKitWebProcess with pid of this extension. Use below to print it:
// g_print("Webext pid: %d (To debug, attach to WebKitWebProcess with this pid)\n", getpid());
this_extension = extension;
parentUniqueId = g_variant_get_int32(user_data);
g_signal_connect(extension, "page-created", G_CALLBACK(web_page_created_callback), NULL);
// To hook into javascript execution:
g_signal_connect (webkit_script_world_get_default (), "window-object-cleared", G_CALLBACK (window_object_cleared_callback), NULL);
// Create DBus server for this web extension
webkitgtk_extension_dbus_name = combineStrInt((char *) WEBKITGTK_EXTENSION_DBUS_NAME_PREFIX, (gint32) getpid());
webkitgtk_extension_dbus_path = combineStrInt((char *) WEBKITGTK_EXTENSION_DBUS_PATH_PREFIX, (gint32) getpid());
dbus_introspection_xml = g_new (gchar, strlen(dbus_introspection_xml_template) + strlen(WEBKITGTK_EXTENSION_DBUS_INTERFACE) + 1);
g_sprintf (dbus_introspection_xml, dbus_introspection_xml_template, WEBKITGTK_EXTENSION_DBUS_INTERFACE);
dbus_node = g_dbus_node_info_new_for_xml (dbus_introspection_xml, NULL);
g_assert (dbus_node != NULL);
guint owner_id;
owner_id = g_bus_own_name (G_BUS_TYPE_SESSION,
webkitgtk_extension_dbus_name,
G_BUS_NAME_OWNER_FLAGS_REPLACE | G_BUS_NAME_OWNER_FLAGS_ALLOW_REPLACEMENT,
on_bus_acquired,
NULL, /* on_name_acquired */
NULL, /* on_name_lost */
NULL,
NULL);
g_assert (owner_id != 0);
}
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