1 files changed, 53 insertions, 0 deletions
diff --git a/widget/cocoa/ViewRegion.h b/widget/cocoa/ViewRegion.h
new file mode 100644
index 0000000000..a8efccaff3
--- /dev/null
+++ b/widget/cocoa/ViewRegion.h
@@ -0,0 +1,53 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef ViewRegion_h
+#define ViewRegion_h
+
+#include "Units.h"
+#include "nsTArray.h"
+
+@class NSView;
+
+namespace mozilla {
+
+/**
+ * Manages a set of NSViews to cover a LayoutDeviceIntRegion.
+ */
+class ViewRegion {
+public:
+  ~ViewRegion();
+
+  mozilla::LayoutDeviceIntRegion Region() { return mRegion; }
+
+  /**
+   * Update the region.
+   * @param aRegion  The new region.
+   * @param aCoordinateConverter  The nsChildView to use for converting
+   *   LayoutDeviceIntRect device pixel coordinates into Cocoa NSRect coordinates.
+   * @param aContainerView  The view that's going to be the superview of the
+   *   NSViews which will be created for this region.
+   * @param aViewCreationCallback  A block that instantiates new NSViews.
+   * @return  Whether or not the region changed.
+   */
+  bool UpdateRegion(const mozilla::LayoutDeviceIntRegion& aRegion,
+                    const nsChildView& aCoordinateConverter,
+                    NSView* aContainerView,
+                    NSView* (^aViewCreationCallback)());
+
+  /**
+   * Return an NSView from the region, if there is any.
+   */
+  NSView* GetAnyView() { return mViews.Length() > 0 ? mViews[0] : nil; }
+
+private:
+  mozilla::LayoutDeviceIntRegion mRegion;
+  nsTArray<NSView*> mViews;
+};
+
+} // namespace mozilla
+
+#endif // ViewRegion_h