Algorithm for deciding if a frame's selection should be hidden

third_party/WebKit/Source/core/editing/FrameSelection.h

 /*
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights
  * reserved.
  *
  * 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
@@ skipping 14 matching lines @@
  */
 
 #ifndef FrameSelection_h
 #define FrameSelection_h
 
 #include <memory>
 #include "core/CoreExport.h"
 #include "core/dom/Range.h"
 #include "core/dom/SynchronousMutationObserver.h"
 #include "core/editing/EphemeralRange.h"
-#include "core/editing/LayoutSelection.h"
 #include "core/editing/VisiblePosition.h"
 #include "core/editing/VisibleSelection.h"
 #include "core/editing/iterators/TextIteratorBehavior.h"
 #include "core/layout/ScrollAlignment.h"
 #include "platform/Timer.h"
 #include "platform/geometry/IntRect.h"
 #include "platform/geometry/LayoutRect.h"
 #include "platform/graphics/PaintInvalidationReason.h"
 #include "platform/heap/Handle.h"
 #include "platform/wtf/Noncopyable.h"
@@ skipping 78 matching lines @@
                     SetSelectionOptions = kCloseTyping | kClearTypingStyle,
                     CursorAlignOnScroll = CursorAlignOnScroll::kIfNeeded,
                     TextGranularity = kCharacterGranularity);
   bool SetSelectedRange(
       const EphemeralRange&,
       TextAffinity,
       SelectionDirectionalMode = SelectionDirectionalMode::kNonDirectional,
       FrameSelection::SetSelectionOptions = kCloseTyping | kClearTypingStyle);
   void SelectAll();
   void Clear();
+  bool IsActive() const;

[Xiaocheng, 2017/05/02 20:05:17]

"Active" is a heavily overloaded term.

Judging from the unit tests related to range selection in contenteditable div,
it seems that this function only determines if the selection (caret or range)
should be painted or not. If so, could you make it clear?

[hugoh_UTC2, 2017/05/03 07:18:55]

It is not only used for deciding if a selection is painted or not. As yosin@
pointed out, "even if we don't paint selection, selection is still available".

 
   // TODO(tkent): These two functions were added to fix crbug.com/695211 without
   // changing focus behavior. Once we fix crbug.com/690272, we can remove these
   // functions.
   // setSelectionDeprecated() returns true if didSetSelectionDeprecated() should
   // be called.
   bool SetSelectionDeprecated(const SelectionInDOMTree&,
                               SetSelectionOptions = kCloseTyping |
                                                     kClearTypingStyle,
                               TextGranularity = kCharacterGranularity);
@@ skipping 91 matching lines @@
 
   HTMLFormElement* CurrentForm() const;
 
   // TODO(tkent): This function has a bug that scrolling doesn't work well in
   // a case of RangeSelection. crbug.com/443061
   void RevealSelection(
       const ScrollAlignment& = ScrollAlignment::kAlignCenterIfNeeded,
       RevealExtentOption = kDoNotRevealExtent);
   void SetSelectionFromNone();
 
-  void UpdateAppearance(LayoutSelection::PaintHint);
+  void UpdateAppearance();
   bool ShouldShowBlockCursor() const;
   void SetShouldShowBlockCursor(bool);
 
   void CacheRangeOfDocument(Range*);
   Range* DocumentCachedRange() const;
   void ClearDocumentCachedRange();
 
   FrameCaret& FrameCaretForTesting() const { return *frame_caret_; }
 
   std::pair<int, int> LayoutSelectionStartEnd();
@@ skipping 45 matching lines @@
   LayoutUnit x_pos_for_vertical_arrow_navigation_;
 
   bool focused_ : 1;
 
   // Controls text granularity used to adjust the selection's extent in
   // moveRangeSelectionExtent.
   std::unique_ptr<GranularityStrategy> granularity_strategy_;
 
   const Member<FrameCaret> frame_caret_;
   bool use_secure_keyboard_entry_when_active_ = false;
-  bool text_control_focused_ = false;
 };
 
 }  // namespace blink
 
 #ifndef NDEBUG
 // Outside the WebCore namespace for ease of invocation from gdb.
 void showTree(const blink::FrameSelection&);
 void showTree(const blink::FrameSelection*);
 #endif
 
 #endif  // FrameSelection_h