a question about MS Windows Clipboard to decrease cpu usage.

[mithrond at gmail.com]

hello, I want to record the content of windows'clipboad,
after search c.l.p. I got some practical answer such as
http://groups.google.com/group/comp.lang.python/browse_thread/thread/57318b87e33e79b0/a7c5d5fcbd4eb58a
I have create my small script, it can get clipboard preliminary. but
now i had a trouble,
I use win32gui.PumpWaitingMessages() in while True: so the script use
9x% cpu. what should i do?
the code was post below.

##################################################
import win32ui, win32clipboard, win32con, win32api, win32gui
def paste():
    win32clipboard.OpenClipboard(0)
    data = win32clipboard.GetClipboardData()
    win32clipboard.CloseClipboard()
    return data
class ClipRecord(object):
    def __init__(self):
        self.hPrev = 0
        self.first   = True
        self.win = win32ui.CreateFrame()
        self.win.CreateWindow(None,'',win32con.WS_OVERLAPPEDWINDOW)

self.win.HookMessage(self.OnDrawClipboard,win32con.WM_DRAWCLIPBOARD)

self.win.HookMessage(self.OnChangeCBChain,win32con.WM_CHANGECBCHAIN)
        self.win.HookMessage(self.OnDestroy,win32con.WM_DESTROY)
        try:

self.hPrev=win32clipboard.SetClipboardViewer(self.win.GetSafeHwnd())
        except win32api.error, err:
            if win32api.GetLastError () == 0:
                # information that there is no other window in chain
                pass
            else:
                raise
        while True:
            win32gui.PumpWaitingMessages()
    def OnChangeCBChain(self, *args):
        msg, wParam, lParam = args[-1][1:4]
        if self.hPrev == wParam:
           # repair the chain
           self.hPrev = lParam
        if self.hPrev:
           # pass the message to the next window in chain
           win32api.SendMessage (self.hPrev, msg, wParam, lParam)
    def OnDrawClipboard(self, *args):
        msg, wParam, lParam = args[-1][1:4]
        if self.first:
           self.first = False
        else:
           print "clipboard content changed"
           print paste()
        if self.hPrev:
           # pass the message to the next window in chain
           win32api.SendMessage (self.hPrev, msg, wParam, lParam)
    def OnDestroy(self):
        if self.hPrev:
            win32clipboard.ChangeClipboardChain(self.win.GetSafeHwnd(),
self.hPrev)
        else:
            win32clipboard.ChangeClipboardChain(self.win.GetSafeHwnd(),
0)
if __name__ == "__main__":
    cr = ClipRecord()