MacViews: Add WidgetEventGenerator to abstract platform-specific event generation for tests.

ui/views/test/event_generator_delegate_mac.mm

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#import <Cocoa/Cocoa.h>
+
+#include "ui/events/event_processor.h"
+#include "ui/events/event_target.h"
+#include "ui/events/event_target_iterator.h"
+#include "ui/events/event_targeter.h"
+#include "ui/events/test/event_generator.h"
+#import "ui/events/test/cocoa_test_event_utils.h"
+#include "ui/gfx/mac/coordinate_conversion.h"
+
+namespace {
+
+// Singleton to provide state for swizzled Objective C methods.
+ui::test::EventGenerator* g_active_generator = NULL;
+
+}  // namespace
+
+@interface NSEventDonor : NSObject
+@end
+
+@implementation NSEventDonor
+
+// Donate +[NSEvent pressedMouseButtons] by retrieving the flags from the
+// active generator.
++ (NSUInteger)pressedMouseButtons {
+  int flags = g_active_generator->flags();
+  NSUInteger bitmask = 0;
+  if (flags & ui::EF_LEFT_MOUSE_BUTTON)
+    bitmask |= 1;
+  if (flags & ui::EF_RIGHT_MOUSE_BUTTON)
+    bitmask |= 1 << 1;
+  if (flags & ui::EF_MIDDLE_MOUSE_BUTTON)
+    bitmask |= 1 << 2;
+  return bitmask;
+}
+
+@end
+
+namespace {
+
+NSPoint ConvertRootPointToTarget(NSWindow* target,
+                                 const gfx::Point& point_in_root) {
+  // Normally this would do [NSWindow convertScreenToBase:]. However, Cocoa can
+  // reposition the window on screen and make things flaky. Initially, just
+  // assume that the contentRect of |target| is at the top-left corner of the
+  // screen.
+  NSRect content_rect = [target contentRectForFrameRect:[target frame]];
+  return NSMakePoint(point_in_root.x(),
+                     NSHeight(content_rect) - point_in_root.y());
+}
+
+// Inverse of ui::EventFlagsFromModifiers().
+NSUInteger EventFlagsToModifiers(int flags) {
+  NSUInteger modifiers = 0;
+  modifiers |= (flags & ui::EF_CAPS_LOCK_DOWN) ? NSAlphaShiftKeyMask : 0;
+  modifiers |= (flags & ui::EF_SHIFT_DOWN) ? NSShiftKeyMask : 0;
+  modifiers |= (flags & ui::EF_CONTROL_DOWN) ? NSControlKeyMask : 0;
+  modifiers |= (flags & ui::EF_ALT_DOWN) ? NSAlternateKeyMask : 0;
+  modifiers |= (flags & ui::EF_COMMAND_DOWN) ? NSCommandKeyMask : 0;
+  // ui::EF_*_MOUSE_BUTTON not handled here.
+  // NSFunctionKeyMask, NSNumericPadKeyMask and NSHelpKeyMask not mapped.
+  return modifiers;
+}
+
+// Picks the corresponding mouse event type for the buttons set in |flags|.
+NSEventType PickMouseEventType(int flags,
+                               NSEventType left,
+                               NSEventType right,
+                               NSEventType other) {
+  if (flags & ui::EF_LEFT_MOUSE_BUTTON)
+    return left;
+  if (flags & ui::EF_RIGHT_MOUSE_BUTTON)
+    return right;
+  return other;
+}
+
+// Inverse of ui::EventTypeFromNative(). If non-null |modifiers| will be set
+// using the inverse of ui::EventFlagsFromNSEventWithModifiers().
+NSEventType EventTypeToNative(ui::EventType ui_event_type,
+                              int flags,
+                              NSUInteger* modifiers) {
+  if (modifiers)
+    *modifiers = EventFlagsToModifiers(flags);
+  switch (ui_event_type) {
+    case ui::ET_UNKNOWN:
+      return 0;
+    case ui::ET_KEY_PRESSED:
+      return NSKeyDown;
+    case ui::ET_KEY_RELEASED:
+      return NSKeyUp;
+    case ui::ET_MOUSE_PRESSED:
+      return PickMouseEventType(flags,
+                                NSLeftMouseDown,
+                                NSRightMouseDown,
+                                NSOtherMouseDown);
+    case ui::ET_MOUSE_RELEASED:
+      return PickMouseEventType(flags,
+                                NSLeftMouseUp,
+                                NSRightMouseUp,
+                                NSOtherMouseUp);
+    case ui::ET_MOUSE_DRAGGED:
+      return PickMouseEventType(flags,
+                                NSLeftMouseDragged,
+                                NSRightMouseDragged,
+                                NSOtherMouseDragged);
+    case ui::ET_MOUSE_MOVED:
+      return NSMouseMoved;
+    case ui::ET_MOUSEWHEEL:
+      return NSScrollWheel;
+    case ui::ET_MOUSE_ENTERED:
+      return NSMouseEntered;
+    case ui::ET_MOUSE_EXITED:
+      return NSMouseExited;
+    case ui::ET_SCROLL_FLING_START:
+      return NSEventTypeSwipe;
+    default:
+      NOTREACHED();
+      return 0;
+  }
+}
+
+// Emulate the dispatching that would be performed by -[NSWindow sendEvent:].
+// sendEvent is a black box which (among other things) will try to peek at the
+// event queue and can block indefinitely.
+void EmulateSendEvent(NSWindow* window, NSEvent* event) {
+  NSResponder* responder = [window firstResponder];
+  switch ([event type]) {
+    case NSKeyDown:
+      [responder keyDown:event];
+      return;
+    case NSKeyUp:
+      [responder keyUp:event];
+      return;
+  }
+
+  // For mouse events, NSWindow will use -[NSView hitTest:] for the initial
+  // mouseDown, and then keep track of the NSView returned. The toolkit-views
+  // RootView does this too. So, for tests, assume tracking will be done there,
+  // and the NSWindow's contentView is wrapping a views::internal::RootView.
+  responder = [window contentView];
+  switch ([event type]) {
+    case NSLeftMouseDown:
+      [responder mouseDown:event];
+      break;
+    case NSRightMouseDown:
+      [responder rightMouseDown:event];
+      break;
+    case NSOtherMouseDown:
+      [responder otherMouseDown:event];
+      break;
+    case NSLeftMouseUp:
+      [responder mouseUp:event];
+      break;
+    case NSRightMouseUp:
+      [responder rightMouseUp:event];
+      break;
+    case NSOtherMouseUp:
+      [responder otherMouseUp:event];
+      break;
+    case NSLeftMouseDragged:
+      [responder mouseDragged:event];
+      break;
+    case NSRightMouseDragged:
+      [responder rightMouseDragged:event];
+      break;
+    case NSOtherMouseDragged:
+      [responder otherMouseDragged:event];
+      break;
+    case NSMouseMoved:
+      // Assumes [NSWindow acceptsMouseMovedEvents] would return YES, and that
+      // NSTrackingAreas have been appropriately installed on |responder|.
+      [responder mouseMoved:event];
+      break;
+    case NSScrollWheel:
+      [responder scrollWheel:event];
+      break;
+    case NSMouseEntered:
+    case NSMouseExited:
+      // With the assumptions in NSMouseMoved, it doesn't make sense for the
+      // generator to handle entered/exited separately. It's the responsibility
+      // of views::internal::RootView to convert the moved events into entered
+      // and exited events for the individual views.
+      NOTREACHED();
+      break;
+    case NSEventTypeSwipe:
+      // NSEventTypeSwipe events can't be generated using public interfaces on
+      // NSEvent, so this will need to be handled at a higher level.
+      NOTREACHED();
+      break;
+    default:
+      NOTREACHED();
+  }
+}
+
+void DispatchMouseEventInWindow(NSWindow* window,
+                                ui::EventType event_type,
+                                const gfx::Point& point_in_root,
+                                int flags) {
+  NSUInteger click_count = 0;
+  if (event_type == ui::ET_MOUSE_PRESSED ||
+      event_type == ui::ET_MOUSE_RELEASED) {
+    if (flags & ui::EF_IS_TRIPLE_CLICK)
+      click_count = 3;
+    else if (flags & ui::EF_IS_DOUBLE_CLICK)
+      click_count = 2;
+    else
+      click_count = 1;
+  }
+  NSPoint point = ConvertRootPointToTarget(window, point_in_root);
+  NSUInteger modifiers = 0;
+  NSEventType type = EventTypeToNative(event_type, flags, &modifiers);
+  NSEvent* event = [NSEvent mouseEventWithType:type
+                                      location:point
+                                 modifierFlags:modifiers
+                                     timestamp:0
+                                  windowNumber:[window windowNumber]
+                                       context:nil
+                                   eventNumber:0
+                                    clickCount:click_count
+                                      pressure:1.0];
+
+  // Typically events go through NSApplication. For tests, dispatch the event
+  // directly to make things more predicatble.
+  EmulateSendEvent(window, event);
+}
+
+// Implementation of ui::test::EventGeneratorDelegate for Mac. Everything
+// defined inline is just a stub. Interesting overrides are defined below the
+// class.
+class EventGeneratorDelegateMac : public ui::EventTarget,
+                                  public ui::EventSource,
+                                  public ui::EventProcessor,
+                                  public ui::EventTargeter,
+                                  public ui::test::EventGeneratorDelegate {
+ public:
+  EventGeneratorDelegateMac(ui::test::EventGenerator* owner, NSWindow* window);
+  virtual ~EventGeneratorDelegateMac() {}
+
+  // Overridden from ui::EventTarget:
+  virtual bool CanAcceptEvent(const ui::Event& event) OVERRIDE { return true; }
+  virtual ui::EventTarget* GetParentTarget()  OVERRIDE { return NULL; }
+  virtual scoped_ptr<ui::EventTargetIterator> GetChildIterator() const OVERRIDE;
+  virtual ui::EventTargeter* GetEventTargeter() OVERRIDE {
+    return this;
+  }
+
+  // Overridden from ui::EventHandler (via ui::EventTarget):
+  virtual void OnMouseEvent(ui::MouseEvent* event) OVERRIDE;
+
+  // Overridden from ui::EventSource:
+  virtual ui::EventProcessor* GetEventProcessor() OVERRIDE { return this; }
+
+  // Overridden from ui::EventProcessor:
+  virtual ui::EventTarget* GetRootTarget() OVERRIDE { return this; }
+
+  // Overridden from ui::EventDispatcherDelegate (via ui::EventProcessor):
+  virtual bool CanDispatchToTarget(EventTarget* target) OVERRIDE {
+    return true;
+  }
+
+  // Overridden from ui::test::EventGeneratorDelegate:
+  virtual ui::EventTarget* GetTargetAt(const gfx::Point& location) OVERRIDE {
+    return this;
+  }
+  virtual ui::EventSource* GetEventSource(ui::EventTarget* target) OVERRIDE {
+    return this;
+  }
+  virtual gfx::Point CenterOfTarget(
+      const ui::EventTarget* target) const OVERRIDE;
+  virtual gfx::Point CenterOfWindow(gfx::NativeWindow window) const OVERRIDE;
+
+  virtual void ConvertPointFromTarget(const ui::EventTarget* target,
+                                      gfx::Point* point) const OVERRIDE {}
+  virtual void ConvertPointToTarget(const ui::EventTarget* target,
+                                    gfx::Point* point) const OVERRIDE {}
+  virtual void ConvertPointFromHost(const ui::EventTarget* hosted_target,
+                                    gfx::Point* point) const OVERRIDE {}
+
+ private:
+  ui::test::EventGenerator* owner_;
+  NSWindow* window_;
+  ScopedClassSwizzler swizzle_pressed_;
+
+  DISALLOW_COPY_AND_ASSIGN(EventGeneratorDelegateMac);
+};
+
+EventGeneratorDelegateMac::EventGeneratorDelegateMac(
+    ui::test::EventGenerator* owner, NSWindow* window)
+    : owner_(owner),
+      window_(window),
+      swizzle_pressed_([NSEvent class],
+                       [NSEventDonor class],
+                       @selector(pressedMouseButtons)) {
+}
+
+scoped_ptr<ui::EventTargetIterator>
+EventGeneratorDelegateMac::GetChildIterator() const {
+  // Return NULL to dispatch all events to the result of GetRootTarget().
+  return scoped_ptr<ui::EventTargetIterator>();
+}
+
+void EventGeneratorDelegateMac::OnMouseEvent(ui::MouseEvent* event) {
+  // For mouse drag events, ensure the swizzled methods return the right flags.
+  base::AutoReset<ui::test::EventGenerator*> reset(&g_active_generator, owner_);
+  DispatchMouseEventInWindow(window_,
+                             event->type(),
+                             event->location(),
+                             event->changed_button_flags());
+}
+
+gfx::Point EventGeneratorDelegateMac::CenterOfTarget(
+    const ui::EventTarget* target) const {
+  DCHECK_EQ(target, this);
+  return CenterOfWindow(window_);
+}
+
+gfx::Point EventGeneratorDelegateMac::CenterOfWindow(
+    gfx::NativeWindow window) const {
+  DCHECK_EQ(window, window_);
+  return gfx::ScreenRectFromNSRect([window frame]).CenterPoint();
+}
+
+}  // namespace
+
+namespace ui {
+namespace test {
+
+// static
+EventGeneratorDelegate* EventGenerator::CreateDefaultPlatformDelegate(
+    EventGenerator* owner,
+    gfx::NativeWindow root_window,
+    gfx::NativeWindow window) {
+  return new EventGeneratorDelegateMac(owner, window);
+}
+
+}  // namespace test
+}  // namespace ui