--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/name/blackcap/exifwasher/Misc.kt	Wed Apr 08 20:29:12 2020 -0700
@@ -0,0 +1,163 @@
+/*
+ * Miscellaneous utility stuff.
+ */
+package name.blackcap.exifwasher
+
+import java.awt.Component
+import java.awt.Cursor
+import java.awt.Toolkit
+import javax.swing.*
+import kotlin.annotation.*
+import kotlin.properties.ReadWriteProperty
+import kotlin.reflect.KProperty
+
+/**
+ * Delegate that makes a var that can only be set once. This is commonly
+ * needed in Swing, because some vars inevitably need to be declared at
+ * outer levels but initialized in the Swing event dispatch thread.
+ */
+class SetOnce<T: Any>: ReadWriteProperty<Any?,T> {
+    private var value: T? = null
+
+    override operator fun getValue(thisRef: Any?, property: KProperty<*>): T {
+        if (value == null) {
+            throw RuntimeException("${property.name} has not been initialized")
+        } else {
+            return value!!
+        }
+    }
+
+    @Synchronized
+    override operator fun setValue(thisRef: Any?, property: KProperty<*>, newValue: T): Unit {
+        if (value != null) {
+            throw RuntimeException("${property.name} has already been initialized")
+        }
+        value = newValue
+    }
+}
+
+/**
+ * Run something in the Swing thread, asynchronously.
+ * @param block lambda containing code to run
+ */
+fun inSwingThread(block: () -> Unit) {
+    SwingUtilities.invokeLater(Runnable(block))
+}
+
+/**
+ * Run something in the Swing thread, synchronously.
+ * @param block lambda containing code to run
+ */
+fun inSynSwingThread(block: () -> Unit) {
+    SwingUtilities.invokeAndWait(Runnable(block))
+}
+
+/**
+ * Make a shortcut for a menu item, using the standard combining key
+ * (control, command, etc.) for the system we're on.
+ * @param key KeyEvent constant describing the key
+ */
+fun JMenuItem.makeShortcut(key: Int): Unit {
+    val SC_KEY_MASK = Toolkit.getDefaultToolkit().menuShortcutKeyMask
+    setAccelerator(KeyStroke.getKeyStroke(key, SC_KEY_MASK))
+}
+
+/**
+ * Given a MenuElement object, get the item whose text matches the
+ * specified text.
+ * @param text to match
+ * @return first matched element, null if no match found
+ */
+fun MenuElement.getItem(name: String) : JMenuItem? {
+    subElements.forEach {
+        val jMenuItem = it.component as? JMenuItem
+        if (jMenuItem?.text == name) {
+            return jMenuItem
+        }
+    }
+    return null
+}
+
+/**
+ * Change to the standard wait cursor.
+ */
+fun Component.useWaitCursor() {
+    this.cursor = Cursor.getPredefinedCursor(Cursor.WAIT_CURSOR))
+}
+
+/**
+ * Return back to the normal cursor().
+ */
+fun Component.useNormalCursor() {
+    this.cursor = Cursor.defaultCursor
+}
+
+/**
+ * Thrown if the programmer botches something in our DSL.
+ */
+class SwingWorkerException(message: String): Exception(message) { }
+
+/**
+ * A simplified SwingWorker DSL. It does not support intermediate
+ * results. Just lets one define a background task and something
+ * to execute when complete.
+ *
+ * @param T Type returned by inBackground (Java doInBackground) task.
+ */
+class SwingWorkerBuilder<T>: SwingWorker<T,Unit>() {
+    private var inBackgroundLambda: (SwingWorkerBuilder.() -> T)? = null
+    private var whenDoneLambda: (SwingWorkerBuilder.() -> Unit)? = null
+
+    private fun setOnce<U>(prop: KMutableProperty<(SwingWorkerBuilder.() -> U)?>, value: SwingWorkerBuilder.() -> U) {
+        if (prop.get() != null) {
+            throw SwingWorkerException(prop.name.removeSuffix("Lambda") + " already defined!")
+        }
+        prop.set(value)
+    }
+
+    /**
+     * Define the inBackground task.
+     */
+    fun inBackground(lambda: SwingWorkerBuilder.() -> T): Unit {
+        setOnce<T>(::inBackgroundLambda, lambda)
+    }
+
+    /**
+     * Define the whenDone task.
+     */
+    fun whenDone(lambda: SwingWorkerBuilder.() -> Unit): Unit {
+        setOnce<Unit>(::whenDoneLambda, lambda)
+    }
+
+    /* standard overrides for SwingWorker follow */
+
+    override fun doInBackground(): T = inBackgroundLambda?.invoke(this)
+
+    override fun done(): Unit = whenDoneLambda?.invoke(this)
+
+    override fun execute(): Unit {
+        if (inBackgroundLambda == null) {
+            throw SwingWorkerException("inBackground not defined!")
+        } else {
+            super.execute()
+        }
+    }
+}
+
+/**
+ * Provides for an outer swingWorker block to contain the DSL.
+ */
+fun swingWorker<T>(initializer: SwingWorkerBuilder.() -> Unit): Unit {
+    SwingWorkerBuilder<T>().run {
+        initializer()
+        execute()
+    }
+}
+
+/**
+ * Close a dialog (don't just hide it).
+ */
+fun JDialog.close() {
+    setVisible(false)
+    dispose()
+}