gecko-dev/layout/generic/nsHTMLReflowCommand.h

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#ifndef nsHTMLReflowCommand_h___
#define nsHTMLReflowCommand_h___
#include "nsReflowType.h"
#include "nsVoidArray.h"
#include <stdio.h>
#include "nsIAtom.h"

class  nsIFrame;
class  nsPresContext;
class  nsIRenderingContext;
struct nsHTMLReflowMetrics;
struct nsSize;

// Reflow command flags
#define NS_RC_CREATED_DURING_DOCUMENT_LOAD 0x0001


/**
 * A reflow command is an object that is generated in response to a content
 * model change notification. The reflow command is given to a presentation
 * shell where it is queued and then dispatched by invoking the reflow
 * commands's Dispatch() member function.
 *
 * Reflow command processing follows a path from the root frame down to the
 * target frame (the frame for which the reflow command is destined). Reflow
 * commands are processed by invoking the frame's Reflow() member function.
 *
 * The typical flow of control for a given reflow command starts with a content
 * change notification. The content notifications are sent to document observers.
 * The presentation shell forwards the notifications to the style set. The style
 * system responds to the notifications by creating new frame (or destroying
 * existing frames) as appropriate, and then generating a reflow command.
 *
 * @see nsIDocumentObserver
 * @see nsIStyleSet
 * @see nsIFrameReflow#Reflow()
 * @see nsIPresShell#AppendReflowCommand()
 * @see nsIPresShell#ProcessReflowCommands()
 */
class nsHTMLReflowCommand {
public:
  /**
   * Construct an HTML reflow command of type aReflowType and with target
   * frame aTargetFrame. You can also specify an optional child frame, e.g.
   * to indicate the inserted child frame
   */
  nsHTMLReflowCommand(nsIFrame*    aTargetFrame,
                      nsReflowType aReflowType,
                      nsIAtom*     aChildListName);

  ~nsHTMLReflowCommand();

  /**
   * Get the target of the reflow command.
   */
  nsIFrame* GetTarget() const { return mTargetFrame; }

  /**
   * Get the type of reflow command.
   */
  nsReflowType Type() const { return mType; }

  /**
   * Returns the name of the child list to which the child frame belongs.
   * Only used for reflow command types FrameAppended, FrameInserted, and
   * FrameRemoved
   *
   * Returns nsnull if the child frame is associated with the unnamed
   * principal child list
   */
  nsIAtom* GetChildListName() const { return mListName; }

  /**
   * Dump out the reflow-command to out
   */
  nsresult List(FILE* out) const;

   /**
    * Get/set reflow command flags
    */
  PRInt32 GetFlagBits() { return mFlags; }
  void AddFlagBits(PRInt32 aBits) { mFlags |= aBits; }
  void RemoveFlagBits(PRInt32 aBits) { mFlags &= ~aBits; }

  /**
   * DEPRECATED compatibility methods
   */
  nsresult GetTarget(nsIFrame*& aTargetFrame) const {
    aTargetFrame = mTargetFrame;
    return NS_OK;
  }

  nsresult GetType(nsReflowType& aReflowType) const {
    aReflowType = mType;
    return NS_OK;
  }
  
  nsresult GetChildListName(nsIAtom*& aListName) const {
    aListName = mListName;
    NS_IF_ADDREF(aListName);
    return NS_OK;
  }

private:
  nsReflowType      mType;
  nsIFrame*         mTargetFrame;
  nsCOMPtr<nsIAtom> mListName;
  // XXXbz remove the flags?  They're not being used for much...
  PRInt32         mFlags;
};

#endif /* nsHTMLReflowCommand_h___ */