Replace the temporary file hack currently used to change Bitcoin-Qt's dock icon (OS X) with a buffer-based solution.

src/qt/macdockiconhandler.mm

@@ -6,7 +6,7 @@
 
 #include <QImageWriter>
 #include <QMenu>
-#include <QTemporaryFile>
+#include <QBuffer>
 #include <QWidget>
 
 #undef slots
@@ -95,14 +95,14 @@ void MacDockIconHandler::setIcon(const QIcon &icon)
         QSize size = icon.actualSize(QSize(128, 128));
         QPixmap pixmap = icon.pixmap(size);
 
-        // write temp file hack (could also be done through QIODevice [memory])
-        QTemporaryFile notificationIconFile;
-        if (!pixmap.isNull() && notificationIconFile.open()) {
-            QImageWriter writer(&notificationIconFile, "PNG");
+        // Write image into a R/W buffer from raw pixmap, then save the image.
+        QBuffer notificationBuffer;
+        if (!pixmap.isNull() && notificationBuffer.open(QIODevice::ReadWrite)) {
+            QImageWriter writer(&notificationBuffer, "PNG");
             if (writer.write(pixmap.toImage())) {
-                const char *cString = notificationIconFile.fileName().toUtf8().data();
-                NSString *macString = [NSString stringWithCString:cString encoding:NSUTF8StringEncoding];
-                image =  [[NSImage alloc] initWithContentsOfFile:macString];
+                NSData* macImgData = [NSData dataWithBytes:notificationBuffer.buffer().data()
+                                             length:notificationBuffer.buffer().size()];
+                image =  [[NSImage alloc] initWithData:macImgData];
             }
         }