MacViews: Implement Tooltips

ui/base/cocoa/tool_tip_base_view.mm

+// Copyright 2015 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 "ui/base/cocoa/tool_tip_base_view.h"
+
+#include "base/logging.h"
+
+// Below is the nasty tooltip stuff -- copied from WebKit's WebHTMLView.mm
+// with minor modifications for code style and commenting.
+//
+//  The 'public' interface is -setToolTipAtMousePoint:. This differs from
+// -setToolTip: in that the updated tooltip takes effect immediately,
+//  without the user's having to move the mouse out of and back into the view.
+//
+// Unfortunately, doing this requires sending fake mouseEnter/Exit events to
+// the view, which in turn requires overriding some internal tracking-rect
+// methods (to keep track of its owner & userdata, which need to be filled out
+// in the fake events.) --snej 7/6/09
+
+
+/*
+ * Copyright (C) 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
+ *           (C) 2006, 2007 Graham Dennis (graham.dennis@gmail.com)
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1.  Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ * 2.  Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in the
+ *     documentation and/or other materials provided with the distribution.
+ * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
+ *     its contributors may be used to endorse or promote products derived
+ *     from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+// Any non-zero value will do, but using something recognizable might help us
+// debug some day.
+const NSTrackingRectTag kTrackingRectTag = 0xBADFACE;
+
+@implementation ToolTipBaseView
+
+// Override of a public NSView method, replacing the inherited functionality.
+// See above for rationale.
+- (NSTrackingRectTag)addTrackingRect:(NSRect)rect
+                               owner:(id)owner
+                            userData:(void *)data
+                        assumeInside:(BOOL)assumeInside {
+  DCHECK(trackingRectOwner_ == nil);
+  trackingRectOwner_ = owner;
+  trackingRectUserData_ = data;
+  return kTrackingRectTag;
+}
+
+// Override of (apparently) a private NSView method(!) See above for rationale.
+- (NSTrackingRectTag)_addTrackingRect:(NSRect)rect
+                                owner:(id)owner
+                             userData:(void *)data
+                         assumeInside:(BOOL)assumeInside
+                       useTrackingNum:(int)tag {
+  DCHECK(tag == 0 || tag == kTrackingRectTag);
+  DCHECK(trackingRectOwner_ == nil);
+  trackingRectOwner_ = owner;
+  trackingRectUserData_ = data;
+  return kTrackingRectTag;
+}
+
+// Override of (apparently) a private NSView method(!) See above for rationale.
+- (void)_addTrackingRects:(NSRect *)rects
+                    owner:(id)owner
+             userDataList:(void **)userDataList
+         assumeInsideList:(BOOL *)assumeInsideList
+             trackingNums:(NSTrackingRectTag *)trackingNums
+                    count:(int)count {
+  DCHECK(count == 1);
+  DCHECK(trackingNums[0] == 0 || trackingNums[0] == kTrackingRectTag);
+  DCHECK(trackingRectOwner_ == nil);
+  trackingRectOwner_ = owner;
+  trackingRectUserData_ = userDataList[0];
+  trackingNums[0] = kTrackingRectTag;
+}
+
+// Override of a public NSView method, replacing the inherited functionality.
+// See above for rationale.
+- (void)removeTrackingRect:(NSTrackingRectTag)tag {
+  if (tag == 0)
+    return;
+
+  if (tag == kTrackingRectTag) {
+    trackingRectOwner_ = nil;
+    return;
+  }
+
+  if (tag == lastToolTipTag_) {
+    [super removeTrackingRect:tag];
+    lastToolTipTag_ = 0;
+    return;
+  }
+
+  // If any other tracking rect is being removed, we don't know how it was
+  // created and it's possible there's a leak involved (see Radar 3500217).
+  NOTREACHED();
+}
+
+// Override of (apparently) a private NSView method(!)
+- (void)_removeTrackingRects:(NSTrackingRectTag *)tags count:(int)count {
+  for (int i = 0; i < count; ++i) {
+    int tag = tags[i];
+    if (tag == 0)
+      continue;
+    DCHECK(tag == kTrackingRectTag);
+    trackingRectOwner_ = nil;
+  }
+}
+
+// Sends a fake NSMouseExited event to the view for its current tracking rect.
+- (void)_sendToolTipMouseExited {
+  // Nothing matters except window, trackingNumber, and userData.
+  int windowNumber = [[self window] windowNumber];
+  NSEvent* fakeEvent = [NSEvent enterExitEventWithType:NSMouseExited
+                                              location:NSZeroPoint
+                                         modifierFlags:0
+                                             timestamp:0
+                                          windowNumber:windowNumber
+                                               context:NULL
+                                           eventNumber:0
+                                        trackingNumber:kTrackingRectTag
+                                              userData:trackingRectUserData_];
+  [trackingRectOwner_ mouseExited:fakeEvent];
+}
+
+// Sends a fake NSMouseEntered event to the view for its current tracking rect.
+- (void)_sendToolTipMouseEntered {
+  // Nothing matters except window, trackingNumber, and userData.
+  int windowNumber = [[self window] windowNumber];
+  NSEvent* fakeEvent = [NSEvent enterExitEventWithType:NSMouseEntered
+                                              location:NSZeroPoint
+                                         modifierFlags:0
+                                             timestamp:0
+                                          windowNumber:windowNumber
+                                               context:NULL
+                                           eventNumber:0
+                                        trackingNumber:kTrackingRectTag
+                                              userData:trackingRectUserData_];
+  [trackingRectOwner_ mouseEntered:fakeEvent];
+}
+
+// Sets the view's current tooltip, to be displayed at the current mouse
+// location. (This does not make the tooltip appear -- as usual, it only
+// appears after a delay.) Pass null to remove the tooltip.
+- (void)setToolTipAtMousePoint:(NSString *)string {
+  NSString *toolTip = [string length] == 0 ? nil : string;
+  if ((toolTip && toolTip_ && [toolTip isEqualToString:toolTip_]) ||
+      (!toolTip && !toolTip_)) {
+    return;
+  }
+
+  if (toolTip_) {
+    [self _sendToolTipMouseExited];
+  }
+
+  toolTip_.reset([toolTip copy]);
+
+  if (toolTip) {
+    // See radar 3500217 for why we remove all tooltips
+    // rather than just the single one we created.
+    [self removeAllToolTips];
+    NSRect wideOpenRect = NSMakeRect(-100000, -100000, 200000, 200000);
+    lastToolTipTag_ = [self addToolTipRect:wideOpenRect
+                                     owner:self
+                                  userData:NULL];
+    [self _sendToolTipMouseEntered];
+  }
+}
+
+// NSView calls this to get the text when displaying the tooltip.
+- (NSString *)view:(NSView *)view
+  stringForToolTip:(NSToolTipTag)tag
+             point:(NSPoint)point
+          userData:(void *)data {
+  return [[toolTip_ copy] autorelease];
+}
+
+@end