Merged revisions 64104,64117 via svnmerge from

svn+ssh://pythondev@svn.python.org/python/trunk

........
  r64104 | benjamin.peterson | 2008-06-10 21:40:25 -0500 (Tue, 10 Jun 2008) | 2 lines

  add the multiprocessing package to fulfill PEP 371
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  r64117 | benjamin.peterson | 2008-06-11 07:26:31 -0500 (Wed, 11 Jun 2008) | 2 lines

  fix import of multiprocessing by juggling imports
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1 files changed, 201 insertions, 0 deletions

diff --git a/Lib/multiprocessing/heap.py b/Lib/multiprocessing/heap.py
new file mode 100644
index 0000000..ab6cf16
--- /dev/null
+++ b/Lib/multiprocessing/heap.py
@@ -0,0 +1,201 @@
+#
+# Module which supports allocation of memory from an mmap
+#
+# multiprocessing/heap.py
+#
+# Copyright (c) 2007-2008, R Oudkerk --- see COPYING.txt
+#
+
+import bisect
+import mmap
+import tempfile
+import os
+import sys
+import threading
+import itertools
+
+import _multiprocessing
+from multiprocessing.util import Finalize, info
+from multiprocessing.forking import assert_spawning
+
+__all__ = ['BufferWrapper']
+
+#
+# Inheirtable class which wraps an mmap, and from which blocks can be allocated
+#
+
+if sys.platform == 'win32':
+
+    from ._multiprocessing import win32
+
+    class Arena(object):
+
+        _counter = itertools.count()
+
+        def __init__(self, size):
+            self.size = size
+            self.name = 'pym-%d-%d' % (os.getpid(), next(Arena._counter))
+            self.buffer = mmap.mmap(-1, self.size, tagname=self.name)
+            assert win32.GetLastError() == 0, 'tagname already in use'
+            self._state = (self.size, self.name)
+
+        def __getstate__(self):
+            assert_spawning(self)
+            return self._state
+
+        def __setstate__(self, state):
+            self.size, self.name = self._state = state
+            self.buffer = mmap.mmap(-1, self.size, tagname=self.name)
+            assert win32.GetLastError() == win32.ERROR_ALREADY_EXISTS
+
+else:
+
+    class Arena(object):
+
+        def __init__(self, size):
+            self.buffer = mmap.mmap(-1, size)
+            self.size = size
+            self.name = None
+
+#
+# Class allowing allocation of chunks of memory from arenas
+#
+
+class Heap(object):
+
+    _alignment = 8
+
+    def __init__(self, size=mmap.PAGESIZE):
+        self._lastpid = os.getpid()
+        self._lock = threading.Lock()
+        self._size = size
+        self._lengths = []
+        self._len_to_seq = {}
+        self._start_to_block = {}
+        self._stop_to_block = {}
+        self._allocated_blocks = set()
+        self._arenas = []
+
+    @staticmethod
+    def _roundup(n, alignment):
+        # alignment must be a power of 2
+        mask = alignment - 1
+        return (n + mask) & ~mask
+
+    def _malloc(self, size):
+        # returns a large enough block -- it might be much larger
+        i = bisect.bisect_left(self._lengths, size)
+        if i == len(self._lengths):
+            length = self._roundup(max(self._size, size), mmap.PAGESIZE)
+            self._size *= 2
+            info('allocating a new mmap of length %d', length)
+            arena = Arena(length)
+            self._arenas.append(arena)
+            return (arena, 0, length)
+        else:
+            length = self._lengths[i]
+            seq = self._len_to_seq[length]
+            block = seq.pop()
+            if not seq:
+                del self._len_to_seq[length], self._lengths[i]
+
+        (arena, start, stop) = block
+        del self._start_to_block[(arena, start)]
+        del self._stop_to_block[(arena, stop)]
+        return block
+
+    def _free(self, block):
+        # free location and try to merge with neighbours
+        (arena, start, stop) = block
+
+        try:
+            prev_block = self._stop_to_block[(arena, start)]
+        except KeyError:
+            pass
+        else:
+            start, _ = self._absorb(prev_block)
+
+        try:
+            next_block = self._start_to_block[(arena, stop)]
+        except KeyError:
+            pass
+        else:
+            _, stop = self._absorb(next_block)
+
+        block = (arena, start, stop)
+        length = stop - start
+
+        try:
+            self._len_to_seq[length].append(block)
+        except KeyError:
+            self._len_to_seq[length] = [block]
+            bisect.insort(self._lengths, length)
+
+        self._start_to_block[(arena, start)] = block
+        self._stop_to_block[(arena, stop)] = block
+
+    def _absorb(self, block):
+        # deregister this block so it can be merged with a neighbour
+        (arena, start, stop) = block
+        del self._start_to_block[(arena, start)]
+        del self._stop_to_block[(arena, stop)]
+
+        length = stop - start
+        seq = self._len_to_seq[length]
+        seq.remove(block)
+        if not seq:
+            del self._len_to_seq[length]
+            self._lengths.remove(length)
+
+        return start, stop
+
+    def free(self, block):
+        # free a block returned by malloc()
+        assert os.getpid() == self._lastpid
+        self._lock.acquire()
+        try:
+            self._allocated_blocks.remove(block)
+            self._free(block)
+        finally:
+            self._lock.release()
+
+    def malloc(self, size):
+        # return a block of right size (possibly rounded up)
+        assert 0 <= size < sys.maxsize
+        if os.getpid() != self._lastpid:
+            self.__init__()                     # reinitialize after fork
+        self._lock.acquire()
+        try:
+            size = self._roundup(max(size,1), self._alignment)
+            (arena, start, stop) = self._malloc(size)
+            new_stop = start + size
+            if new_stop < stop:
+                self._free((arena, new_stop, stop))
+            block = (arena, start, new_stop)
+            self._allocated_blocks.add(block)
+            return block
+        finally:
+            self._lock.release()
+
+#
+# Class representing a chunk of an mmap -- can be inherited
+#
+
+class BufferWrapper(object):
+
+    _heap = Heap()
+
+    def __init__(self, size):
+        assert 0 <= size < sys.maxsize
+        block = BufferWrapper._heap.malloc(size)
+        self._state = (block, size)
+        Finalize(self, BufferWrapper._heap.free, args=(block,))
+
+    def get_address(self):
+        (arena, start, stop), size = self._state
+        address, length = _multiprocessing.address_of_buffer(arena.buffer)
+        assert size <= length
+        return address + start
+
+    def get_size(self):
+        return self._state[1]