New Java-style threading module. The doc strings are in a separate module.

1 files changed, 638 insertions, 0 deletions

diff --git a/Lib/threading.py b/Lib/threading.py
new file mode 100644
index 0000000..79319c1
--- /dev/null
+++ b/Lib/threading.py
@@ -0,0 +1,638 @@
+# threading.py:
+# Proposed new threading module, emulating a subset of Java's threading model
+
+import sys
+import time
+import thread
+import traceback
+import StringIO
+
+# Rename some stuff so "from threading import *" is safe
+
+_sys = sys
+del sys
+
+_time = time.time
+_sleep = time.sleep
+del time
+
+_start_new_thread = thread.start_new_thread
+_allocate_lock = thread.allocate_lock
+_get_ident = thread.get_ident
+del thread
+
+_print_exc = traceback.print_exc
+del traceback
+
+_StringIO = StringIO.StringIO
+del StringIO
+
+
+# Debug support (adapted from ihooks.py)
+
+_VERBOSE = 0
+
+if __debug__:
+
+    class _Verbose:
+
+        def __init__(self, verbose=None):
+            if verbose is None:
+                verbose = _VERBOSE
+            self.__verbose = verbose
+
+        def _note(self, format, *args):
+            if self.__verbose:
+                format = format % args
+                format = "%s: %s\n" % (
+                    currentThread().getName(), format)
+                _sys.stderr.write(format)
+
+else:
+    # Disable this when using "python -O"
+    class _Verbose:
+        def __init__(self, verbose=None):
+            pass
+        def _note(self, *args):
+            pass
+
+
+# Synchronization classes
+
+Lock = _allocate_lock
+
+def RLock(*args, **kwargs):
+    return apply(_RLock, args, kwargs)
+
+class _RLock(_Verbose):
+    
+    def __init__(self, verbose=None):
+        _Verbose.__init__(self, verbose)
+        self.__block = _allocate_lock()
+        self.__owner = None
+        self.__count = 0
+
+    def __repr__(self):
+        return "<%s(%s, %d)>" % (
+                self.__class__.__name__,
+                self.__owner and self.__owner.getName(),
+                self.__count)
+
+    def acquire(self, blocking=1):
+        me = currentThread()
+        if self.__owner is me:
+            self.__count = self.__count + 1
+            if __debug__:
+                self._note("%s.acquire(%s): recursive success", self, blocking)
+            return 1
+        rc = self.__block.acquire(blocking)
+        if rc:
+            self.__owner = me
+            self.__count = 1
+            if __debug__:
+                self._note("%s.acquire(%s): initial succes", self, blocking)
+        else:
+            if __debug__:
+                self._note("%s.acquire(%s): failure", self, blocking)
+        return rc
+
+    def release(self):
+        me = currentThread()
+        assert self.__owner is me, "release() of un-acquire()d lock"
+        self.__count = count = self.__count - 1
+        if not count:
+            self.__owner = None
+            self.__block.release()
+            if __debug__:
+                self._note("%s.release(): final release", self)
+        else:
+            if __debug__:
+                self._note("%s.release(): non-final release", self)
+
+    # Internal methods used by condition variables
+
+    def _acquire_restore(self, (count, owner)):
+        self.__block.acquire()
+        self.__count = count
+        self.__owner = owner
+        if __debug__:
+            self._note("%s._acquire_restore()", self)
+
+    def _release_save(self):
+        if __debug__:
+            self._note("%s._release_save()", self)
+        count = self.__count
+        self.__count = 0
+        owner = self.__owner
+        self.__owner = None
+        self.__block.release()
+        return (count, owner)
+
+    def _is_owned(self):
+        return self.__owner is currentThread()
+
+
+def Condition(*args, **kwargs):
+    return apply(_Condition, args, kwargs)
+
+class _Condition(_Verbose):
+
+    def __init__(self, lock=None, verbose=None):
+        _Verbose.__init__(self, verbose)
+        if lock is None:
+            lock = RLock()
+        self.__lock = lock
+        # Export the lock's acquire() and release() methods
+        self.acquire = lock.acquire
+        self.release = lock.release
+        # If the lock defines _release_save() and/or _acquire_restore(),
+        # these override the default implementations (which just call
+        # release() and acquire() on the lock).  Ditto for _is_owned().
+        try:
+            self._release_save = lock._release_save
+        except AttributeError:
+            pass
+        try:
+            self._acquire_restore = lock._acquire_restore
+        except AttributeError:
+            pass
+        try:
+            self._is_owned = lock._is_owned
+        except AttributeError:
+            pass
+        self.__waiters = []
+
+    def __repr__(self):
+        return "<Condition(%s, %d)>" % (self.__lock, len(self.__waiters))
+
+    def _release_save(self):
+        self.__lock.release()           # No state to save
+
+    def _acquire_restore(self, x):
+        self.__lock.acquire()           # Ignore saved state
+
+    def _is_owned(self):
+        if self.__lock.acquire(0):
+            self.__lock.release()
+            return 0
+        else:
+            return 1
+
+    def wait(self, timeout=None):
+        me = currentThread()
+        assert self._is_owned(), "wait() of un-acquire()d lock"
+        waiter = _allocate_lock()
+        waiter.acquire()
+        self.__waiters.append(waiter)
+        saved_state = self._release_save()
+        if timeout is None:
+            waiter.acquire()
+            if __debug__:
+                self._note("%s.wait(): got it", self)
+        else:
+            endtime = _time() + timeout
+            delay = 0.000001 # 1 usec
+            while 1:
+                gotit = waiter.acquire(0)
+                if gotit or _time() >= endtime:
+                    break
+                _sleep(delay)
+                if delay < 1.0:
+                    delay = delay * 2.0
+            if not gotit:
+                if __debug__:
+                    self._note("%s.wait(%s): timed out", self, timeout)
+                try:
+                    self.__waiters.remove(waiter)
+                except ValueError:
+                    pass
+            else:
+                if __debug__:
+                    self._note("%s.wait(%s): got it", self, timeout)
+        self._acquire_restore(saved_state)
+
+    def notify(self, n=1):
+        me = currentThread()
+        assert self._is_owned(), "notify() of un-acquire()d lock"
+        __waiters = self.__waiters
+        waiters = __waiters[:n]
+        if not waiters:
+            if __debug__:
+                self._note("%s.notify(): no waiters", self)
+            return
+        self._note("%s.notify(): notifying %d waiter%s", self, n,
+                   n!=1 and "s" or "")
+        for waiter in waiters:
+            waiter.release()
+            try:
+                __waiters.remove(waiter)
+            except ValueError:
+                pass
+
+    def notifyAll(self):
+        self.notify(len(self.__waiters))
+
+
+def Semaphore(*args, **kwargs):
+    return apply(_Semaphore, args, kwargs)
+
+class _Semaphore(_Verbose):
+
+    # After Tim Peters' semaphore class, but bnot quite the same (no maximum)
+
+    def __init__(self, value=1, verbose=None):
+        assert value >= 0, "Semaphore initial value must be >= 0"
+        _Verbose.__init__(self, verbose)
+        self.__cond = Condition(Lock())
+        self.__value = value
+
+    def acquire(self, blocking=1):
+        rc = 0
+        self.__cond.acquire()
+        while self.__value == 0:
+            if not blocking:
+                break
+            self.__cond.wait()
+        else:
+            self.__value = self.__value - 1
+            rc = 1
+        self.__cond.release()
+        return rc
+
+    def release(self):
+        self.__cond.acquire()
+        self.__value = self.__value + 1
+        self.__cond.notify()
+        self.__cond.release()
+
+
+def Event(*args, **kwargs):
+    return apply(_Event, args, kwargs)
+
+class _Event(_Verbose):
+
+    # After Tim Peters' event class (without is_posted())
+
+    def __init__(self, verbose=None):
+        _Verbose.__init__(self, verbose)
+        self.__cond = Condition(Lock())
+        self.__flag = 0
+
+    def isSet(self):
+        return self.__flag
+
+    def set(self):
+        self.__cond.acquire()
+        self.__flag = 1
+        self.__cond.notifyAll()
+        self.__cond.release()
+
+    def clear(self):
+        self.__cond.acquire()
+        self.__flag = 0
+        self.__cond.release()
+
+    def wait(self, timeout=None):
+        self.__cond.acquire()
+        if not self.__flag:
+            self.__cond.wait(timeout)
+        self.__cond.release()
+
+
+# Helper to generate new thread names
+_counter = 0
+def _newname(template="Thread-%d"):
+    global _counter
+    _counter = _counter + 1
+    return template % _counter
+
+# Active thread administration
+_active_limbo_lock = _allocate_lock()
+_active = {}
+_limbo = {}
+
+
+# Main class for threads
+
+class Thread(_Verbose):
+
+    __initialized = 0
+
+    def __init__(self, group=None, target=None, name=None,
+                 args=(), kwargs={}, verbose=None):
+	assert group is None, "group argument must be None for now"
+        _Verbose.__init__(self, verbose)
+        self.__target = target
+        self.__name = str(name or _newname())
+        self.__args = args
+        self.__kwargs = kwargs
+        self.__daemonic = self._set_daemon()
+        self.__started = 0
+        self.__stopped = 0
+        self.__block = Condition(Lock())
+        self.__initialized = 1
+
+    def _set_daemon(self):
+        # Overridden in _MainThread and _DummyThread
+        return currentThread().isDaemon()
+
+    def __repr__(self):
+        assert self.__initialized, "Thread.__init__() was not called"
+        status = "initial"
+        if self.__started:
+            status = "started"
+        if self.__stopped:
+            status = "stopped"
+        if self.__daemonic:
+            status = status + " daemon"
+        return "<%s(%s, %s)>" % (self.__class__.__name__, self.__name, status)
+
+    def start(self):
+        assert self.__initialized, "Thread.__init__() not called"
+        assert not self.__started, "thread already started"
+        if __debug__:
+            self._note("%s.start(): starting thread", self)
+        _active_limbo_lock.acquire()
+        _limbo[self] = self
+        _active_limbo_lock.release()
+        _start_new_thread(self.__bootstrap, ())
+        self.__started = 1
+        _sleep(0.000001)    # 1 usec, to let the thread run (Solaris hack)
+
+    def run(self):
+        if self.__target:
+            apply(self.__target, self.__args, self.__kwargs)
+
+    def __bootstrap(self):
+        try:
+            self.__started = 1
+            _active_limbo_lock.acquire()
+            _active[_get_ident()] = self
+            del _limbo[self]
+            _active_limbo_lock.release()
+            if __debug__:
+                self._note("%s.__bootstrap(): thread started", self)
+            try:
+                self.run()
+            except SystemExit:
+                if __debug__:
+                    self._note("%s.__bootstrap(): raised SystemExit", self)
+            except:
+                if __debug__:
+                    self._note("%s.__bootstrap(): unhandled exception", self)
+                s = _StringIO()
+                _print_exc(file=s)
+                _sys.stderr.write("Exception in thread %s:\n%s\n" %
+                                 (self.getName(), s.getvalue()))
+            else:
+                if __debug__:
+                    self._note("%s.__bootstrap(): normal return", self)
+        finally:
+            self.__stop()
+            self.__delete()
+
+    def __stop(self):
+        self.__block.acquire()
+        self.__stopped = 1
+        self.__block.notifyAll()
+        self.__block.release()
+
+    def __delete(self):
+        _active_limbo_lock.acquire()
+        del _active[_get_ident()]
+        _active_limbo_lock.release()
+
+    def join(self, timeout=None):
+        assert self.__initialized, "Thread.__init__() not called"
+	assert self.__started, "cannot join thread before it is started"
+        assert self is not currentThread(), "cannot join current thread"
+        if __debug__:
+            if not self.__stopped:
+                self._note("%s.join(): waiting until thread stops", self)
+        self.__block.acquire()
+        if timeout is None:
+	    while not self.__stopped:
+                self.__block.wait()
+            if __debug__:
+                self._note("%s.join(): thread stopped", self)
+        else:
+            deadline = time.time() + timeout
+            while not self.__stopped:
+                delay = deadline - time.time()
+                if delay <= 0:
+                    if __debug__:
+                        self._note("%s.join(): timed out", self)
+                    break
+                self.__block.wait(delay)
+            else:
+                if __debug__:
+                    self._note("%s.join(): thread stopped", self)
+        self.__block.release()
+
+    def getName(self):
+        assert self.__initialized, "Thread.__init__() not called"
+        return self.__name
+
+    def setName(self, name):
+        assert self.__initialized, "Thread.__init__() not called"
+        self.__name = str(name)
+
+    def isAlive(self):
+        assert self.__initialized, "Thread.__init__() not called"
+        return self.__started and not self.__stopped
+    
+    def isDaemon(self):
+        assert self.__initialized, "Thread.__init__() not called"
+        return self.__daemonic
+
+    def setDaemon(self, daemonic):
+        assert self.__initialized, "Thread.__init__() not called"
+        assert not self.__started, "cannot set daemon status of active thread"
+        self.__daemonic = daemonic
+
+
+# Special thread class to represent the main thread
+# This is garbage collected through an exit handler
+
+class _MainThread(Thread):
+
+    def __init__(self):
+        Thread.__init__(self, name="MainThread")
+        self._Thread__started = 1
+        _active_limbo_lock.acquire()
+        _active[_get_ident()] = self
+        _active_limbo_lock.release()
+        try:
+            self.__oldexitfunc = _sys.exitfunc
+        except AttributeError:
+            self.__oldexitfunc = None
+        _sys.exitfunc = self.__exitfunc
+
+    def _set_daemon(self):
+        return 0
+
+    def __exitfunc(self):
+        self._Thread__stop()
+        t = _pickSomeNonDaemonThread()
+        if t:
+            if __debug__:
+                self._note("%s: waiting for other threads", self)
+        while t:
+            t.join()
+            t = _pickSomeNonDaemonThread()
+        if self.__oldexitfunc:
+            if __debug__:
+                self._note("%s: calling exit handler", self)
+            self.__oldexitfunc()
+        if __debug__:
+            self._note("%s: exiting", self)
+        self._Thread__delete()
+
+def _pickSomeNonDaemonThread():
+    for t in enumerate():
+        if not t.isDaemon() and t.isAlive():
+            return t
+    return None
+
+
+# Dummy thread class to represent threads not started here.
+# These aren't garbage collected when they die,
+# nor can they be waited for.
+# Their purpose is to return *something* from currentThread().
+# They are marked as daemon threads so we won't wait for them
+# when we exit (conform previous semantics).
+
+class _DummyThread(Thread):
+    
+    def __init__(self):
+        Thread.__init__(self, name=_newname("Dummy-%d"))
+        self.__Thread_started = 1
+        _active_limbo_lock.acquire()
+        _active[_get_ident()] = self
+        _active_limbo_lock.release()
+
+    def _set_daemon(self):
+        return 1
+
+    def join(self):
+        assert 0, "cannot join a dummy thread"
+
+
+# Global API functions
+
+def currentThread():
+    try:
+        return _active[_get_ident()]
+    except KeyError:
+        print "currentThread(): no current thread for", _get_ident()
+        return _DummyThread()
+
+def activeCount():
+    _active_limbo_lock.acquire()
+    count = len(_active) + len(_limbo)
+    _active_limbo_lock.release()
+    return count
+
+def enumerate():
+    _active_limbo_lock.acquire()
+    active = _active.values() + _limbo.values()
+    _active_limbo_lock.release()
+    return active
+
+
+# Create the main thread object
+
+_MainThread()
+
+
+# Self-test code
+
+def _test():
+
+    import whrandom
+
+    class BoundedQueue(_Verbose):
+
+        def __init__(self, limit):
+            _Verbose.__init__(self)
+            self.mon = RLock()
+            self.rc = Condition(self.mon)
+            self.wc = Condition(self.mon)
+            self.limit = limit
+            self.queue = []
+
+        def put(self, item):
+            self.mon.acquire()
+            while len(self.queue) >= self.limit:
+                self._note("put(%s): queue full", item)
+                self.wc.wait()
+            self.queue.append(item)
+            self._note("put(%s): appended, length now %d",
+                       item, len(self.queue))
+            self.rc.notify()
+            self.mon.release()
+
+        def get(self):
+            self.mon.acquire()
+            while not self.queue:
+                self._note("get(): queue empty")
+                self.rc.wait()
+            item = self.queue[0]
+            del self.queue[0]
+            self._note("get(): got %s, %d left", item, len(self.queue))
+            self.wc.notify()
+            self.mon.release()
+            return item
+
+    class ProducerThread(Thread):
+
+        def __init__(self, queue, quota):
+            Thread.__init__(self, name="Producer")
+            self.queue = queue
+            self.quota = quota
+
+        def run(self):
+            from whrandom import random
+            counter = 0
+            while counter < self.quota:
+                counter = counter + 1
+                self.queue.put("%s.%d" % (self.getName(), counter))
+                _sleep(random() * 0.00001)
+
+
+    class ConsumerThread(Thread):
+
+        def __init__(self, queue, count):
+            Thread.__init__(self, name="Consumer")
+            self.queue = queue
+            self.count = count
+
+        def run(self):
+            while self.count > 0:
+                item = self.queue.get()
+                print item
+                self.count = self.count - 1
+
+    import time
+
+    NP = 3
+    QL = 4
+    NI = 5
+
+    Q = BoundedQueue(QL)
+    P = []
+    for i in range(NP):
+        t = ProducerThread(Q, NI)
+        t.setName("Producer-%d" % (i+1))
+        P.append(t)
+    C = ConsumerThread(Q, NI*NP)
+    for t in P:
+        t.start()
+        _sleep(0.000001)
+    C.start()
+    for t in P:
+        t.join()
+    C.join()
+
+if __name__ == '__main__':
+    _test()