X11 Motif C++ Widget Base Class

UIComponent.cpp

/*
 * BasicComponent.cpp
 *
 *  Created on: Oct 4, 2014
 *      Author: wtruong
 */

#include <cstdio>
#include "UIComponent.h"

UIComponent::~UIComponent() {
	if (mWidget) {
	  XtRemoveCallback(mWidget, XmNdestroyCallback,
	                   UIComponent::widgetDestroyedCallback,
	                   (XtPointer)this);
	  XtDestroyWidget(mWidget);
	}
}

void UIComponent::manage()
{
  if (mWidget) {
    //TODO: Put a check to see if XmNdestroyCallback is registered
    XtManageChild(mWidget);
  }
}

void UIComponent::unmanage()
{
  if (mWidget) {
    XtUnmanageChild(mWidget);
  }
}

void UIComponent::widgetDestroyed()
{
  mWidget = NULL;
}

UIComponent::UIComponent(const char* n)
    : mName(n)
{
  mWidget = NULL;
}

void UIComponent::installDestroyHandler()
{
  if (mWidget) {
    XtAddCallback(mWidget, XmNdestroyCallback,
                  UIComponent::widgetDestroyedCallback,
                  (XtPointer)this);
  }
}

void UIComponent::setDefaultResources(const Widget,
    const char* resourceSpec[])
{
  int i;
  Display *dpy = XtDisplay(mWidget);
  XrmDatabase rdb = NULL;

  // Create empty resource database
  rdb = XrmGetStringDatabase("");

  // Add the Component resources, prepending the name of the component
  i = 0;
  while (resourceSpec[i] != NULL) {
    char buf[1000];

    snprintf(buf, 1000, "*%s%s", mName, resourceSpec[i++]);
    XrmPutLineResource(&rdb, buf);
  }

  // Merge them into the Xt database, with lowest precedence
  if (rdb) {
    XrmDatabase db = XtDatabase(dpy);
    XrmCombineDatabase(rdb, &db, FALSE);
  }
}

void UIComponent::getResources(const XtResourceList resources,
                               int numResources)
{
  if (mWidget && resources) {
    XtGetSubresources(XtParent(mWidget), (XtPointer)this,
                      mName, className(),
                      resources, numResources,
                      NULL, 0);
  }
}

void UIComponent::widgetDestroyedCallback(Widget,
                                          XtPointer clientData,
                                          XtPointer)
{
  UIComponent* obj = (UIComponent*)clientData;
  obj->widgetDestroyed();
}

UIComponent.h

#ifndef UICOMPONENT_H_
#define UICOMPONENT_H_

#include <string>
#include <Xm/Xm.h>

class UIComponent
{
  public:
    virtual ~UIComponent();
    virtual void manage();
    virtual void unmanage();
    virtual const char* const className() { return "UIComponent"; }
    const Widget BaseWidget() { return (mWidget); }

  protected:
    const char* mName;
    Widget mWidget;

    virtual void widgetDestroyed();
    UIComponent(const char* name);
    // Must install this in the derived class's constructor
    // once w_ is instantitated
    void installDestroyHandler();
    // TODO: Convert const char* to vector to be more safe
    void setDefaultResources(const Widget, const char*[]);
    void getResources(const XtResourceList, int);

  private:
    // Interface between XmNdestroyCallback and this class
    static void widgetDestroyedCallback(Widget, XtPointer, XtPointer);
};

#endif /* UICOMPONENT_H_ */