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diff --git a/dom/html/nsTextEditorState.h b/dom/html/nsTextEditorState.h
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+/* -*- 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 nsTextEditorState_h__
+#define nsTextEditorState_h__
+
+#include "nsString.h"
+#include "nsITextControlElement.h"
+#include "nsITextControlFrame.h"
+#include "nsCycleCollectionParticipant.h"
+#include "mozilla/dom/Element.h"
+#include "mozilla/Attributes.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/WeakPtr.h"
+
+class nsTextInputListener;
+class nsTextControlFrame;
+class nsTextInputSelectionImpl;
+class nsAnonDivObserver;
+class nsISelectionController;
+class nsFrameSelection;
+class nsIEditor;
+class nsITextControlElement;
+class nsFrame;
+
+namespace mozilla {
+namespace dom {
+class HTMLInputElement;
+} // namespace dom
+} // namespace mozilla
+
+/**
+ * nsTextEditorState is a class which is responsible for managing the state of
+ * plaintext controls.  This currently includes the following HTML elements:
+ *   <input type=text>
+ *   <input type=password>
+ *   <textarea>
+ * and also XUL controls such as <textbox> which use one of these elements behind
+ * the scenes.
+ *
+ * This class is held as a member of HTMLInputElement and nsHTMLTextAreaElement.
+ * The public functions in this class include the public APIs which content/ uses.
+ * Layout code uses the nsITextControlElement interface to invoke functions on this
+ * class.
+ *
+ * The design motivation behind this class is maintaining all of the things which
+ * collectively are considered the "state" of the text control in a single location.
+ * This state includes several things:
+ *
+ *  * The control's value.  This value is stored in the mValue member, and is only
+ *    used when there is no frame for the control, or when the editor object has
+ *    not been initialized yet.
+ *
+ *  * The control's associated frame.  This value is stored in the mBoundFrame member.
+ *    A text control might never have an associated frame during its life cycle,
+ *    or might have several different ones, but at any given moment in time there is
+ *    a maximum of 1 bound frame to each text control.
+ *
+ *  * The control's associated editor.  This value is stored in the mEditor member.
+ *    An editor is initilized for the control only when necessary (that is, when either
+ *    the user is about to interact with the text control, or when some other code
+ *    needs to access the editor object.  Without a frame bound to the control, an
+ *    editor is never initialzied.  Once initialized, the editor might outlive the frame,
+ *    in which case the same editor will be used if a new frame gets bound to the
+ *    text control.
+ *
+ *  * The anonymous content associated with the text control's frame, including the
+ *    value div (the DIV element responsible for holding the value of the text control)
+ *    and the placeholder div (the DIV element responsible for holding the placeholder
+ *    value of the text control.)  These values are stored in the mRootNode and
+ *    mPlaceholderDiv members, respectively.  They will be created when a
+ *    frame is bound to the text control.  They will be destroyed when the frame is
+ *    unbound from the object.  We could try and hold on to the anonymous content
+ *    between different frames, but unfortunately that is not currently possible
+ *    because they are not unbound from the document in time.
+ *
+ *  * The frame selection controller.  This value is stored in the mSelCon member.
+ *    The frame selection controller is responsible for maintaining the selection state
+ *    on a frame.  It is created when a frame is bound to the text control element,
+ *    and will be destroy when the frame is being unbound from the text control element.
+ *    It is created alongside with the frame selection object which is stored in the
+ *    mFrameSel member.
+ *
+ *  * The editor text listener.  This value is stored in the mTextListener member.
+ *    Its job is to listen to selection and keyboard events, and act accordingly.
+ *    It is created when an a frame is first bound to the control, and will be destroyed
+ *    when the frame is unbound from the text control element.
+ *
+ *  * The editor's cached value.  This value is stored in the mCachedValue member.
+ *    It is used to improve the performance of append operations to the text
+ *    control.  A mutation observer stored in the mMutationObserver has the job of
+ *    invalidating this cache when the anonymous contect containing the value is
+ *    changed.
+ *
+ *  * The editor's cached selection properties.  These vales are stored in the
+ *    mSelectionProperties member, and include the selection's start, end and
+ *    direction. They are only used when there is no frame available for the
+ *    text field.
+ *
+ *
+ * As a general rule, nsTextEditorState objects own the value of the text control, and any
+ * attempt to retrieve or set the value must be made through those objects.  Internally,
+ * the value can be represented in several different ways, based on the state the control is
+ * in.
+ *
+ *   * When the control is first initialized, its value is equal to the default value of
+ *     the DOM node.  For <input> text controls, this default value is the value of the
+ *     value attribute.  For <textarea> elements, this default value is the value of the
+ *     text node children of the element.
+ *
+ *   * If the value has been changed through the DOM node (before the editor for the object
+ *     is initialized), the value is stored as a simple string inside the mValue member of
+ *     the nsTextEditorState object.
+ *
+ *   * If an editor has been initialized for the control, the value is set and retrievd via
+ *     the nsIPlaintextEditor interface, and is internally managed by the editor as the
+ *     native anonymous content tree attached to the control's frame.
+ *
+ *   * If the text editor state object is unbound from the control's frame, the value is
+ *     transferred to the mValue member variable, and will be managed there until a new
+ *     frame is bound to the text editor state object.
+ */
+
+class RestoreSelectionState;
+
+class nsTextEditorState : public mozilla::SupportsWeakPtr<nsTextEditorState> {
+public:
+  MOZ_DECLARE_WEAKREFERENCE_TYPENAME(nsTextEditorState)
+  explicit nsTextEditorState(nsITextControlElement* aOwningElement);
+  ~nsTextEditorState();
+
+  void Traverse(nsCycleCollectionTraversalCallback& cb);
+  void Unlink();
+
+  nsIEditor* GetEditor();
+  nsISelectionController* GetSelectionController() const;
+  nsFrameSelection* GetConstFrameSelection();
+  nsresult BindToFrame(nsTextControlFrame* aFrame);
+  void UnbindFromFrame(nsTextControlFrame* aFrame);
+  nsresult PrepareEditor(const nsAString *aValue = nullptr);
+  void InitializeKeyboardEventListeners();
+
+  enum SetValueFlags
+  {
+    // The call is for internal processing.
+    eSetValue_Internal              = 0,
+    // The value is changed by a call of setUserInput() from chrome.
+    eSetValue_BySetUserInput        = 1 << 0,
+    // The value is changed by changing value attribute of the element or
+    // something like setRangeText().
+    eSetValue_ByContent             = 1 << 1,
+    // Whether the value change should be notified to the frame/contet nor not.
+    eSetValue_Notify                = 1 << 2
+  };
+  MOZ_MUST_USE bool SetValue(const nsAString& aValue, uint32_t aFlags);
+  void GetValue(nsAString& aValue, bool aIgnoreWrap) const;
+  void EmptyValue() { if (mValue) mValue->Truncate(); }
+  bool IsEmpty() const { return mValue ? mValue->IsEmpty() : true; }
+
+  nsresult CreatePlaceholderNode();
+
+  mozilla::dom::Element* GetRootNode() {
+    return mRootNode;
+  }
+  mozilla::dom::Element* GetPlaceholderNode() {
+    return mPlaceholderDiv;
+  }
+
+  bool IsSingleLineTextControl() const {
+    return mTextCtrlElement->IsSingleLineTextControl();
+  }
+  bool IsTextArea() const {
+    return mTextCtrlElement->IsTextArea();
+  }
+  bool IsPlainTextControl() const {
+    return mTextCtrlElement->IsPlainTextControl();
+  }
+  bool IsPasswordTextControl() const {
+    return mTextCtrlElement->IsPasswordTextControl();
+  }
+  int32_t GetCols() {
+    return mTextCtrlElement->GetCols();
+  }
+  int32_t GetWrapCols() {
+    return mTextCtrlElement->GetWrapCols();
+  }
+  int32_t GetRows() {
+    return mTextCtrlElement->GetRows();
+  }
+
+  // placeholder methods
+  void UpdatePlaceholderVisibility(bool aNotify);
+  bool GetPlaceholderVisibility() {
+    return mPlaceholderVisibility;
+  }
+  void UpdatePlaceholderText(bool aNotify);
+
+  /**
+   * Get the maxlength attribute
+   * @param aMaxLength the value of the max length attr
+   * @returns false if attr not defined
+   */
+  bool GetMaxLength(int32_t* aMaxLength);
+
+  void ClearValueCache() { mCachedValue.Truncate(); }
+
+  void HideSelectionIfBlurred();
+
+  struct SelectionProperties {
+    public:
+      SelectionProperties() : mStart(0), mEnd(0),
+        mDirection(nsITextControlFrame::eForward) {}
+      bool IsDefault() const
+      {
+        return mStart == 0 && mEnd == 0 &&
+               mDirection == nsITextControlFrame::eForward;
+      }
+      int32_t GetStart() const
+      {
+        return mStart;
+      }
+      void SetStart(int32_t value)
+      {
+        mIsDirty = true;
+        mStart = value;
+      }
+      int32_t GetEnd() const
+      {
+        return mEnd;
+      }
+      void SetEnd(int32_t value)
+      {
+        mIsDirty = true;
+        mEnd = value;
+      }
+      nsITextControlFrame::SelectionDirection GetDirection() const
+      {
+        return mDirection;
+      }
+      void SetDirection(nsITextControlFrame::SelectionDirection value)
+      {
+        mIsDirty = true;
+        mDirection = value;
+      }
+      // return true only if mStart, mEnd, or mDirection have been modified
+      bool IsDirty() const
+      {
+        return mIsDirty;
+      }
+    private:
+      int32_t mStart, mEnd;
+      bool mIsDirty = false;
+      nsITextControlFrame::SelectionDirection mDirection;
+  };
+
+  bool IsSelectionCached() const;
+  SelectionProperties& GetSelectionProperties();
+  void SetSelectionProperties(SelectionProperties& aProps);
+  void WillInitEagerly() { mSelectionRestoreEagerInit = true; }
+  bool HasNeverInitializedBefore() const { return !mEverInited; }
+
+  void UpdateEditableState(bool aNotify) {
+    if (mRootNode) {
+      mRootNode->UpdateEditableState(aNotify);
+    }
+  }
+
+private:
+  friend class RestoreSelectionState;
+
+  // not copy constructible
+  nsTextEditorState(const nsTextEditorState&);
+  // not assignable
+  void operator= (const nsTextEditorState&);
+
+  nsresult CreateRootNode();
+
+  void ValueWasChanged(bool aNotify);
+
+  void DestroyEditor();
+  void Clear();
+
+  nsresult InitializeRootNode();
+
+  void FinishedRestoringSelection();
+
+  mozilla::dom::HTMLInputElement* GetParentNumberControl(nsFrame* aFrame) const;
+
+  bool EditorHasComposition();
+
+  class InitializationGuard {
+  public:
+    explicit InitializationGuard(nsTextEditorState& aState) :
+      mState(aState),
+      mGuardSet(false)
+    {
+      if (!mState.mInitializing) {
+        mGuardSet = true;
+        mState.mInitializing = true;
+      }
+    }
+    ~InitializationGuard() {
+      if (mGuardSet) {
+        mState.mInitializing = false;
+      }
+    }
+    bool IsInitializingRecursively() const {
+      return !mGuardSet;
+    }
+  private:
+    nsTextEditorState& mState;
+    bool mGuardSet;
+  };
+  friend class InitializationGuard;
+  friend class PrepareEditorEvent;
+
+  // The text control element owns this object, and ensures that this object
+  // has a smaller lifetime.
+  nsITextControlElement* const MOZ_NON_OWNING_REF mTextCtrlElement;
+  RefPtr<nsTextInputSelectionImpl> mSelCon;
+  RefPtr<RestoreSelectionState> mRestoringSelection;
+  nsCOMPtr<nsIEditor> mEditor;
+  nsCOMPtr<mozilla::dom::Element> mRootNode;
+  nsCOMPtr<mozilla::dom::Element> mPlaceholderDiv;
+  nsTextControlFrame* mBoundFrame;
+  RefPtr<nsTextInputListener> mTextListener;
+  mozilla::Maybe<nsString> mValue;
+  RefPtr<nsAnonDivObserver> mMutationObserver;
+  mutable nsString mCachedValue; // Caches non-hard-wrapped value on a multiline control.
+  // mValueBeingSet is available only while SetValue() is requesting to commit
+  // composition.  I.e., this is valid only while mIsCommittingComposition is
+  // true.  While active composition is being committed, GetValue() needs
+  // the latest value which is set by SetValue().  So, this is cache for that.
+  nsString mValueBeingSet;
+  SelectionProperties mSelectionProperties;
+  bool mEverInited; // Have we ever been initialized?
+  bool mEditorInitialized;
+  bool mInitializing; // Whether we're in the process of initialization
+  bool mValueTransferInProgress; // Whether a value is being transferred to the frame
+  bool mSelectionCached; // Whether mSelectionProperties is valid
+  mutable bool mSelectionRestoreEagerInit; // Whether we're eager initing because of selection restore
+  bool mPlaceholderVisibility;
+  bool mIsCommittingComposition;
+};
+
+inline void
+ImplCycleCollectionUnlink(nsTextEditorState& aField)
+{
+  aField.Unlink();
+}
+
+inline void
+ImplCycleCollectionTraverse(nsCycleCollectionTraversalCallback& aCallback,
+                            nsTextEditorState& aField,
+                            const char* aName,
+                            uint32_t aFlags = 0)
+{
+  aField.Traverse(aCallback);
+}
+
+#endif