html/virtual/virtual.cpp

/////////////////////////////////////////////////////////////////////////////
// Name:        virtua;.cpp
// Purpose:     wxHtml testing example
//              demonstrates virtual file systems feature
/////////////////////////////////////////////////////////////////////////////

// For compilers that support precompilation, includes "wx/wx.h".
#include "wx/wxprec.h"

#ifdef __BORLANDC__
    #pragma hdrstop
#endif

// for all others, include the necessary headers (this file is usually all you
// need because it includes almost all "standard" wxWidgets headers
#ifndef WX_PRECOMP
    #include "wx/wx.h"
#endif


#include "wx/html/htmlwin.h"


// new handler class:

#include "wx/wfstream.h"
#include "wx/mstream.h"


class MyVFS : public wxFileSystemHandler
{
public:
    MyVFS() : wxFileSystemHandler() {}

    wxFSFile* OpenFile(wxFileSystem& fs, const wxString& location);
    bool CanOpen(const wxString& location);
};


bool MyVFS::CanOpen(const wxString& location)
{
    return (GetProtocol(location) == wxT("myVFS"));
}


wxFSFile* MyVFS::OpenFile(wxFileSystem& WXUNUSED(fs), const wxString& location)
{
    wxFSFile *f;
    wxInputStream *str;
    static char buf[1024];
    const wxWX2MBbuf loc = location.ToAscii();

    sprintf(buf, "<html><body><h2><i>You're in Node <u>%s</u></i></h2><p>"
                 "Where do you want to go?<br><blockquote>"
                 "<a href=\"%s-1\">sub-1</a><br>"
                 "<a href=\"%s-2\">sub-2</a><br>"
                 "<a href=\"%s-3\">sub-3</a><br>"
                 "</blockquote></body></html>",
                 (const char*)loc, (const char*)loc, (const char*)loc,
                 (const char*)loc);

    // NB: There's a terrible hack involved: we fill 'buf' with new data every
    //     time this method is called and return new wxMemoryInputStream pointing to it.
    //     This won't work as soon as there are 2+ myVFS files opened. Fortunately,
    //     this won't happen because wxHTML keeps only one "page" file opened at the
    //     time.
    str = new wxMemoryInputStream(buf, strlen(buf));
    f = new wxFSFile(str, location, wxT("text/html"), wxEmptyString, wxDateTime::Today());

    return f;
}


// ----------------------------------------------------------------------------
// private classes
// ----------------------------------------------------------------------------

// Define a new application type, each program should derive a class from wxApp
   class MyApp : public wxApp
   {
   public:
    // override base class virtuals
    // ----------------------------

    // this one is called on application startup and is a good place for the app
    // initialization (doing it here and not in the ctor allows to have an error
    // return: if OnInit() returns false, the application terminates)
      virtual bool OnInit();
   };

// Define a new frame type: this is going to be our main frame
   class MyFrame : public wxFrame
   {
   public:
    // ctor(s)
      MyFrame(const wxString& title, const wxPoint& pos, const wxSize& size);

    // event handlers (these functions should _not_ be virtual)
      void OnQuit(wxCommandEvent& event);
      void OnBack(wxCommandEvent& event);
      void OnForward(wxCommandEvent& event);

   private:
    // any class wishing to process wxWidgets events must use this macro
    DECLARE_EVENT_TABLE()
   };

// ----------------------------------------------------------------------------
// constants
// ----------------------------------------------------------------------------

// IDs for the controls and the menu commands
   enum
   {
    // menu items
   Minimal_Quit = 1,
   Minimal_Back,
   Minimal_Forward,

    // controls start here (the numbers are, of course, arbitrary)
   Minimal_Text = 1000
   };

// ----------------------------------------------------------------------------
// event tables and other macros for wxWidgets
// ----------------------------------------------------------------------------

// the event tables connect the wxWidgets events with the functions (event
// handlers) which process them. It can be also done at run-time, but for the
// simple menu events like this the static method is much simpler.
   BEGIN_EVENT_TABLE(MyFrame, wxFrame)
   EVT_MENU(Minimal_Quit,  MyFrame::OnQuit)
   EVT_MENU(Minimal_Back, MyFrame::OnBack)
   EVT_MENU(Minimal_Forward, MyFrame::OnForward)
   END_EVENT_TABLE()

   // Create a new application object: this macro will allow wxWidgets to create
   // the application object during program execution (it's better than using a
   // static object for many reasons) and also declares the accessor function
   // wxGetApp() which will return the reference of the right type (i.e. MyApp and
   // not wxApp)
   IMPLEMENT_APP(MyApp)

   // ============================================================================
   // implementation
   // ============================================================================

   // ----------------------------------------------------------------------------
   // the application class
   // ----------------------------------------------------------------------------

   // `Main program' equivalent: the program execution "starts" here
   bool MyApp::OnInit()
   {
    // Create the main application window
      MyFrame *frame = new MyFrame(_("wxHtmlWindow testing application"),
         wxDefaultPosition, wxSize(640, 480));

    // Show it and tell the application that it's our main window
    // @@@ what does it do exactly, in fact? is it necessary here?
      frame->Show(true);
      SetTopWindow(frame);
      wxFileSystem::AddHandler(new MyVFS);

    // success: wxApp::OnRun() will be called which will enter the main message
    // loop and the application will run. If we returned false here, the
    // application would exit immediately.
      return true;
   }

// ----------------------------------------------------------------------------
// main frame
// ----------------------------------------------------------------------------

wxHtmlWindow *html;

// frame constructor
   MyFrame::MyFrame(const wxString& title, const wxPoint& pos, const wxSize& size)
   : wxFrame((wxFrame *)NULL, wxID_ANY, title, pos, size)
   {
    // create a menu bar
      wxMenu *menuFile = new wxMenu;
      wxMenu *menuNav = new wxMenu;

      menuFile->Append(Minimal_Quit, _("E&xit"));
      menuNav->Append(Minimal_Back, _("Go &BACK"));
      menuNav->Append(Minimal_Forward, _("Go &FORWARD"));

    // now append the freshly created menu to the menu bar...
      wxMenuBar *menuBar = new wxMenuBar;
      menuBar->Append(menuFile, _("&File"));
      menuBar->Append(menuNav, _("&Navigate"));

    // ... and attach this menu bar to the frame
      SetMenuBar(menuBar);

#if wxUSE_STATUSBAR
      CreateStatusBar(2);
#endif // wxUSE_STATUSBAR

      html = new wxHtmlWindow(this);
      html -> SetRelatedFrame(this, _("VFS Demo: '%s'"));
#if wxUSE_STATUSBAR
      html -> SetRelatedStatusBar(1);
#endif // wxUSE_STATUSBAR
      html -> LoadPage(wxT("start.htm"));
   }


// event handlers

   void MyFrame::OnQuit(wxCommandEvent& WXUNUSED(event))
   {
    // true is to force the frame to close
      Close(true);
   }

   void MyFrame::OnBack(wxCommandEvent& WXUNUSED(event))
   {
   if (!html -> HistoryBack()) wxMessageBox(_("You reached prehistory era!"));
   }


   void MyFrame::OnForward(wxCommandEvent& WXUNUSED(event))
   {
   if (!html -> HistoryForward()) wxMessageBox(_("No more items in history!"));
   }