gecko-dev/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 "nsAutoPtr.h"
#include "nsString.h"
#include "nsITextControlElement.h"
#include "nsITextControlFrame.h"
#include "nsCycleCollectionParticipant.h"
#include "mozilla/dom/Element.h"
#include "mozilla/Attributes.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;
}
}
/**
* 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();
MOZ_WARN_UNUSED_RESULT bool SetValue(const nsAString& aValue,
bool aUserInput,
bool aSetValueAsChanged);
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() {
if (!mRootNode)
CreateRootNode();
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 {
SelectionProperties() : mStart(0), mEnd(0),
mDirection(nsITextControlFrame::eForward) {}
bool IsDefault() const {
return mStart == 0 && mEnd == 0 &&
mDirection == nsITextControlFrame::eForward;
}
int32_t mStart, mEnd;
nsITextControlFrame::SelectionDirection mDirection;
};
bool IsSelectionCached() const;
SelectionProperties& GetSelectionProperties();
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;
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;
nsRefPtr<nsTextInputSelectionImpl> mSelCon;
nsRefPtr<RestoreSelectionState> mRestoringSelection;
nsCOMPtr<nsIEditor> mEditor;
nsCOMPtr<mozilla::dom::Element> mRootNode;
nsCOMPtr<mozilla::dom::Element> mPlaceholderDiv;
nsTextControlFrame* mBoundFrame;
nsRefPtr<nsTextInputListener> mTextListener;
nsAutoPtr<nsCString> mValue;
nsRefPtr<nsAnonDivObserver> mMutationObserver;
mutable nsString mCachedValue; // Caches non-hard-wrapped value on a multiline control.
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
SelectionProperties mSelectionProperties;
bool mPlaceholderVisibility;
};
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