--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/symbian-qemu-0.9.1-12/python-2.6.1/Demo/threads/find.py	Fri Jul 31 15:01:17 2009 +0100
@@ -0,0 +1,155 @@
+# A parallelized "find(1)" using the thread module.
+
+# This demonstrates the use of a work queue and worker threads.
+# It really does do more stats/sec when using multiple threads,
+# although the improvement is only about 20-30 percent.
+# (That was 8 years ago.  In 2002, on Linux, I can't measure
+# a speedup. :-( )
+
+# I'm too lazy to write a command line parser for the full find(1)
+# command line syntax, so the predicate it searches for is wired-in,
+# see function selector() below.  (It currently searches for files with
+# world write permission.)
+
+# Usage: parfind.py [-w nworkers] [directory] ...
+# Default nworkers is 4
+
+
+import sys
+import getopt
+import string
+import time
+import os
+from stat import *
+import thread
+
+
+# Work queue class.  Usage:
+#   wq = WorkQ()
+#   wq.addwork(func, (arg1, arg2, ...)) # one or more calls
+#   wq.run(nworkers)
+# The work is done when wq.run() completes.
+# The function calls executed by the workers may add more work.
+# Don't use keyboard interrupts!
+
+class WorkQ:
+
+    # Invariants:
+
+    # - busy and work are only modified when mutex is locked
+    # - len(work) is the number of jobs ready to be taken
+    # - busy is the number of jobs being done
+    # - todo is locked iff there is no work and somebody is busy
+
+    def __init__(self):
+        self.mutex = thread.allocate()
+        self.todo = thread.allocate()
+        self.todo.acquire()
+        self.work = []
+        self.busy = 0
+
+    def addwork(self, func, args):
+        job = (func, args)
+        self.mutex.acquire()
+        self.work.append(job)
+        self.mutex.release()
+        if len(self.work) == 1:
+            self.todo.release()
+
+    def _getwork(self):
+        self.todo.acquire()
+        self.mutex.acquire()
+        if self.busy == 0 and len(self.work) == 0:
+            self.mutex.release()
+            self.todo.release()
+            return None
+        job = self.work[0]
+        del self.work[0]
+        self.busy = self.busy + 1
+        self.mutex.release()
+        if len(self.work) > 0:
+            self.todo.release()
+        return job
+
+    def _donework(self):
+        self.mutex.acquire()
+        self.busy = self.busy - 1
+        if self.busy == 0 and len(self.work) == 0:
+            self.todo.release()
+        self.mutex.release()
+
+    def _worker(self):
+        time.sleep(0.00001)     # Let other threads run
+        while 1:
+            job = self._getwork()
+            if not job:
+                break
+            func, args = job
+            apply(func, args)
+            self._donework()
+
+    def run(self, nworkers):
+        if not self.work:
+            return # Nothing to do
+        for i in range(nworkers-1):
+            thread.start_new(self._worker, ())
+        self._worker()
+        self.todo.acquire()
+
+
+# Main program
+
+def main():
+    nworkers = 4
+    opts, args = getopt.getopt(sys.argv[1:], '-w:')
+    for opt, arg in opts:
+        if opt == '-w':
+            nworkers = string.atoi(arg)
+    if not args:
+        args = [os.curdir]
+
+    wq = WorkQ()
+    for dir in args:
+        wq.addwork(find, (dir, selector, wq))
+
+    t1 = time.time()
+    wq.run(nworkers)
+    t2 = time.time()
+
+    sys.stderr.write('Total time %r sec.\n' % (t2-t1))
+
+
+# The predicate -- defines what files we look for.
+# Feel free to change this to suit your purpose
+
+def selector(dir, name, fullname, stat):
+    # Look for world writable files that are not symlinks
+    return (stat[ST_MODE] & 0002) != 0 and not S_ISLNK(stat[ST_MODE])
+
+
+# The find procedure -- calls wq.addwork() for subdirectories
+
+def find(dir, pred, wq):
+    try:
+        names = os.listdir(dir)
+    except os.error, msg:
+        print repr(dir), ':', msg
+        return
+    for name in names:
+        if name not in (os.curdir, os.pardir):
+            fullname = os.path.join(dir, name)
+            try:
+                stat = os.lstat(fullname)
+            except os.error, msg:
+                print repr(fullname), ':', msg
+                continue
+            if pred(dir, name, fullname, stat):
+                print fullname
+            if S_ISDIR(stat[ST_MODE]):
+                if not os.path.ismount(fullname):
+                    wq.addwork(find, (fullname, pred, wq))
+
+
+# Call the main program
+
+main()