Visualizza wikitesto di Ottenere informazioni sulle applicazioni client in esecuzione su un display con le funzioni del API di X11

La libreria '''X11''' ci consente anche di ottenere alcune informazioni generiche sulle applicazioni client in esecuzione su un display.

Sarà necessario richiamare la libreria del sistema X11: "''libX11.so.6.3.0'' " , nonché la libreria Xmu: "''libXmu.so.6.2.0'' ".

Mostriamo di seguito un possibile breve codice al riguardo:
 Library "libX11:6.3.0"
 
 Public Struct XTextProperty
   value As Pointer
   encoding As Long
   formatI As Integer
   nitems As Long
 End Struct
 
 Public Struct XClassHint
   res_name As Pointer
   res_class As Pointer
 End Struct
 
 Private Const XA_STRING As Integer = 31
 
 <FONT Color=gray>' ''Display *XOpenDisplay(char *display_name)''
 ' ''Opens a connection to the X server that controls a display.''</font>
 Private Extern XOpenDisplay(display_name As Pointer) As Pointer
 
 <FONT Color=gray>' ''Window XDefaultRootWindow(Display *display)''
 ' ''Return the root window for the default screen.''</font>
 Private Extern XDefaultRootWindow(display As Pointer) As Integer
 
 <FONT Color=gray>' ''Status XGetWMClientMachine(Display *display, Window w, XTextProperty *text_prop_return)
 ' ''Performs an XGetTextProperty() on the WM_CLIENT_MACHINE property.''</font>
 Private Extern XGetWMClientMachine(display As Pointer, w As Long, text_prop_return As XTextProperty) As Integer
 
 <FONT Color=gray>' ''Status XGetCommand(Display *display, Window w, char ***argv_return, int *argc_return)
 ' ''Reads the WM_COMMAND property from the specified window and returns a string list.''</font>
 Private Extern XGetCommand(display As Pointer, w As Long, argv_return As Pointer, argc_return As Pointer) As Integer
 
 <FONT Color=gray>' ''int XFree(void *)''
 ' ''It's a general-purpose Xlib routine that frees the specified data.''</font>
 Private Extern XFree(po As Pointer) As Integer
 
 <FONT Color=gray>' ''char * XGetAtomName(Display *display, Atom atom)''
 ' ''Returns the name associated with the specified atom.''</font>
 Private Extern XGetAtomName(display As Pointer, atom As Long) As Pointer
 
 <FONT Color=gray>' ''XGetWMName(Display *display, Window w, XTextProperty *text_prop_return)''
 ' ''Calls XGetTextProperty() to obtain the WM_NAME property.''</font>
 Private Extern XGetWMName(display As Pointer, w As Long, text_prop_return As XTextProperty) As Integer
 
 <FONT Color=gray>' ''Status XGetWMIconName(Display *display, Window w, XTextProperty *text_prop_return)''
 ' ''Calls XGetTextProperty() to obtain the WM_ICON_NAME property.''</font>
 Private Extern XGetWMIconName(display As Pointer, w As Long, text_prop_return As XTextProperty) As Integer
 
 <FONT Color=gray>' ''Status XQueryTree(Display *display, Window w, Window *root_return, Window *parent_return, Window **children_return, unsigned int *nchildren_return)''
 ' ''Returns the root ID, the parent window ID, a pointer to the list of children windows (NULL when there are no children), and the number of children in the list for the specified window.''</font>
 Private Extern XQueryTree(display As Pointer, w As Long, root_return As Pointer, parent_return As Pointer, children_return As Pointer, nchildren_return As Pointer) As Integer
 
 <FONT Color=gray>' ''Status XGetClassHint(Display *display, Window w, XClassHint *class_hints_return)''
 ' ''Returns the class hint of the specified window to the members of the supplied structure.''</font>
 Private Extern XGetClassHint(display As Pointer, w As Long, class_hints_return As XClassHint) As Integer
 
 <FONT Color=gray>' ''XCloseDisplay (Display *display)''
 ' ''Closes a display or disconnect from the X server.''</font>
 Private Extern XCloseDisplay(display As Pointer)
 
 
 <FONT Color=gray>' ''Window XmuClientWindow(Display *dpy, Window win)''
 ' ''Finds a window at or below the specified window which has a WM_STATE property.''</font>
 Private Extern XmuClientWindow(display As Pointer, w As Long) As Long In "libXmu:6.2.0"
 
 
 <FONT Color=gray>' ''void exit(int status)''
 ' ''Terminates the calling process immediately.Any Open file descriptors belonging To the process are closed And any children Of the process are inherited.''</font>
 Private Extern exitus(status As Integer) In "libc:6" Exec "exit"
 
 
 '''Public''' Sub Main()
 
  Dim i, nc As Integer
  Dim dis, figli As Pointer
  Dim dm, root, client, l As Long
  Dim st As Stream
    
  dis = XOpenDisplay(0)
  If dis == 0 Then Error.Raise("Impossibile aprire lo schermo !")
    
  root = XDefaultRootWindow(dis)
  Proprieta_Clienti(dis, root)
 
  If Not XQueryTree(dis, root, VarPtr(dm), VarPtr(dm), VarPtr(figli), VarPtr(nc)) Then Return
 
  st = Memory figli For Read
  For i = 0 To nc - 1
    Read #st, l
    client = XmuClientWindow(dis, l)
    If client <> 0 Then Proprieta_Clienti(dis, client)
  Next
  st.Close
    
 <FONT Color=gray>' ''Va in chiusura:''</font>
  XCloseDisplay(dis)
  exitus(0)
    
 '''End'''
  
 '''Private''' Procedure Proprieta_Clienti(dis As Pointer, w As Long)
 
  Dim mxtp, nxtp, xtp As New XTextproperty
  Dim clh As New XClassHint
  Dim cli, i As Integer
  Dim clip, p As Pointer
  Dim st As Stream
  Dim s As String
  
  If Not XGetWMClientMachine(dis, w, mxtp) Then
    mxtp.value = 0
    mxtp.encoding = 0
  Endif
 
  clip = Alloc(Sizeof(gb.Integer), 2)
 
  If Not XGetCommand(dis, w, VarPtr(clip), VarPtr(cli)) Then
    If mxtp.value > 0 Then XFree(mxtp.value)
    Return
  Endif
 
 <FONT Color=gray>' ''Scrive l'informazione d'intestazione dell'applicazione:''</font>
  Print "\nFinestra &"; Hex(w); ":"
  If mxtp.value == 0 Then Print "nullo", Hex(w)
  Testo(dis, "  Machine:  ", mxtp)
 
  If XGetWMName(dis, w, nxtp) Then
    Testo(dis, "  Name:  ", nxtp)
    If nxtp.value > 0 Then XFree(nxtp.value)
  Endif
 
  If mxtp.value > 0 Then XFree(mxtp.value)
 
  If XGetWMIconName(dis, w, xtp) <> 0 Then
    Testo(dis, "  Icon Name:  ", xtp)
    If xtp.value > 0 Then XFree(xtp.value)
  Endif
 
 <FONT Color=gray>' ''Scrive il comando dell'applicazione:''</font>
  st = Memory clip For Read
  While i < cli
    Read #st, p
    Print "  Command:  "; String@(p)
    Inc i
  Wend
  st.Close
 
  s = "  Instance/Class:  "
  If XGetClassHint(dis, w, clh) Then
    If clh.res_name > 0 Then
      s &= String@(clh.res_name)
      XFree(clh.res_name)
    Endif
    s &= "/"
    If clh.res_class > 0 Then
      s &= String@(clh.res_class)
      XFree(clh.res_class)
    Endif
  Endif
  Print s
    
 '''End'''
 
 '''Private''' Procedure Testo(dis As Pointer, s As String, xtp As XTextproperty)
  
  If (xtp.encoding == 0) Or (xtp.formatI == 0) Then
    Print "''"
    Return
   Endif
 
  If (xtp.encoding = XA_STRING) And (xtp.formatI == 8) Then
    If xtp.value > 0 Then
      s &= String@(xtp.value)
      Print s
    Endif
  Else
    s &= Sconosciuto(dis, xtp.encoding, xtp.formatI)
  Endif
 
 '''End'''
 
 '''Private''' Function Sconosciuto(dis As Pointer, tipo As Long, formato As Integer) As String
   
  Dim s As String
  
  s = "<Tipo sconosciuto "
    
  If tipo == 0 Then
    s &= "Nessuno"
  Else If XGetAtomName(dis, tipo) > 0 Then
    s &= XGetAtomName(dis, tipo)
  Else
    Print Null
  Endif
 
  s &= CStr(tipo) & " o formato " & CLong(formato) & ">"
    
  Return s
  
 '''End'''