hasStrings Linux (flutter#21388)

hasStrings method for clipboard status, Linux

Author: justinmc

shell/platform/linux/fl_platform_plugin.cc

@@ -17,8 +17,10 @@ static constexpr char kUnknownClipboardFormatError[] =
 static constexpr char kFailedError[] = "Failed";
 static constexpr char kGetClipboardDataMethod[] = "Clipboard.getData";
 static constexpr char kSetClipboardDataMethod[] = "Clipboard.setData";
+static constexpr char kClipboardHasStringsMethod[] = "Clipboard.hasStrings";
 static constexpr char kSystemNavigatorPopMethod[] = "SystemNavigator.pop";
 static constexpr char kTextKey[] = "text";
+static constexpr char kValueKey[] = "value";
 
 static constexpr char kTextPlainFormat[] = "text/plain";
 
@@ -56,6 +58,22 @@ static void clipboard_text_cb(GtkClipboard* clipboard,
   send_response(method_call, response);
 }
 
+// Called when clipboard text received during has_strings.
+static void clipboard_text_has_strings_cb(GtkClipboard* clipboard,
+                                          const gchar* text,
+                                          gpointer user_data) {
+  g_autoptr(FlMethodCall) method_call = FL_METHOD_CALL(user_data);
+
+  g_autoptr(FlValue) result = fl_value_new_map();
+  fl_value_set_string_take(
+      result, kValueKey,
+      fl_value_new_bool(text != nullptr && strlen(text) > 0));
+
+  g_autoptr(FlMethodResponse) response =
+      FL_METHOD_RESPONSE(fl_method_success_response_new(result));
+  send_response(method_call, response);
+}
+
 // Called when Flutter wants to copy to the clipboard.
 static FlMethodResponse* clipboard_set_data(FlPlatformPlugin* self,
                                             FlValue* args) {
@@ -100,7 +118,21 @@ static FlMethodResponse* clipboard_get_data_async(FlPlatformPlugin* self,
   gtk_clipboard_request_text(clipboard, clipboard_text_cb,
                              g_object_ref(method_call));
 
-  // Will response later.
+  // Will respond later.
+  return nullptr;
+}
+
+// Called when Flutter wants to know if the content of the clipboard is able to
+// be pasted, without actually accessing the clipboard content itself.
+static FlMethodResponse* clipboard_has_strings_async(
+    FlPlatformPlugin* self,
+    FlMethodCall* method_call) {
+  GtkClipboard* clipboard =
+      gtk_clipboard_get_default(gdk_display_get_default());
+  gtk_clipboard_request_text(clipboard, clipboard_text_has_strings_cb,
+                             g_object_ref(method_call));
+
+  // Will respond later.
   return nullptr;
 }
 
@@ -131,6 +163,8 @@ static void method_call_cb(FlMethodChannel* channel,
     response = clipboard_set_data(self, args);
   } else if (strcmp(method, kGetClipboardDataMethod) == 0) {
     response = clipboard_get_data_async(self, method_call);
+  } else if (strcmp(method, kClipboardHasStringsMethod) == 0) {
+    response = clipboard_has_strings_async(self, method_call);
   } else if (strcmp(method, kSystemNavigatorPopMethod) == 0) {
     response = system_navigator_pop(self);
   } else {