Get errors back from libnotify

briar-desktop/src/main/kotlin/org/briarproject/briar/desktop/notification/linux/GErrorStruct.kt

+/*
+ * Briar Desktop
+ * Copyright (C) 2021-2022 The Briar Project
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package org.briarproject.briar.desktop.notification.linux
+
+import com.sun.jna.Pointer
+import com.sun.jna.Structure
+import com.sun.jna.Structure.FieldOrder
+
+@FieldOrder("domain", "code", "message") // NON-NLS
+class GErrorStruct : Structure {
+    @JvmField
+    @Volatile
+    var domain /* GQuark */ = 0
+
+    @JvmField
+    @Volatile
+    var code = 0
+
+    @JvmField
+    @Volatile
+    var message: String? = null
+
+    constructor() {
+        clear()
+    }
+
+    constructor(ptr: Pointer?) : super(ptr) {
+        read()
+    }
+}

briar-desktop/src/main/kotlin/org/briarproject/briar/desktop/notification/linux/LibnotifyNotificationProvider.kt

@@ -20,6 +20,7 @@ package org.briarproject.briar.desktop.notification.linux
 import com.sun.jna.Library
 import com.sun.jna.Native
 import com.sun.jna.Pointer
+import com.sun.jna.ptr.PointerByReference
 import mu.KotlinLogging
 import org.briarproject.briar.desktop.notification.VisualNotificationProvider
 import org.briarproject.briar.desktop.utils.InternationalizationUtils.i18n
@@ -126,9 +127,11 @@ object LibnotifyNotificationProvider : VisualNotificationProvider {
          */
         libNotify.notify_notification_set_category(notification, "im.received")
 
-        if (!libNotify.notify_notification_show(notification, null)) {
-            // todo: error handling
+        val errorPointer = PointerByReference()
+        if (!libNotify.notify_notification_show(notification, errorPointer)) {
             LOG.e { "error while sending notification via libnotify" }
+            val error = GErrorStruct(errorPointer.value)
+            LOG.e { "error code: ${error.code}, message: '${error.message}'" }
         }
     }
 
@@ -210,7 +213,7 @@ object LibnotifyNotificationProvider : VisualNotificationProvider {
          *
          * @return true if successful. On error, this will return false and set [error].
          */
-        fun notify_notification_show(notification: Pointer, error: Pointer?): Boolean
+        fun notify_notification_show(notification: Pointer, error: PointerByReference?): Boolean
 
         /**
          * Sets a hint for [key] with value [value]. If [value] is null,