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Viewing changes to src/twisted/vfs/adapters/stream.py

  • Committer: Thomas Hervé
  • Date: 2009-07-08 13:52:04 UTC
  • Revision ID: thomas@canonical.com-20090708135204-df5eesrthifpylf8
Remove twisted copy

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src/twisted/vfs/adapters/stream.py
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import os
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from zope.interface import implements
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from twisted.web2.stream import SimpleStream, IByteStream
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from twisted.vfs.ivfs import IFileSystemLeaf, VFSError
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from twisted.python import components
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class FileSystemLeafStream(SimpleStream):
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    implements(IByteStream)
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    """A stream that reads data from a FileSystemLeaf."""
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    # 65K, minus some slack
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    CHUNK_SIZE = 2 ** 2 ** 2 ** 2 - 32
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    def __init__(self, leaf, start=0, length=None):
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        """
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        Create the stream from leaf. If you specify start and length,
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        use only that portion of the leaf.
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        """
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        self.leaf = leaf
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        self.leaf.open(os.O_RDONLY)
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        self.start = start
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        if length is None:
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            self.length = leaf.getMetadata()['size']
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        else:
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            self.length = length
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    def read(self):
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        if self.leaf is None:
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            return None
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        length = self.length
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        if length == 0:
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            self.leaf = None
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            return None
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        readSize = min(length, self.CHUNK_SIZE)
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        b = self.leaf.readChunk(self.start, readSize)
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        bytesRead = len(b)
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        if bytesRead != readSize:
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            raise VFSError(
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                ("Ran out of data reading vfs leaf %r, expected %d more bytes,"
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                 " got %d") % (self.leaf, readSize, bytesRead))
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        else:
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            self.length -= bytesRead
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            self.start += bytesRead
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            return b
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    def close(self):
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        self.leaf.close()
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        self.leaf = None
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        SimpleStream.close(self)
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components.registerAdapter(FileSystemLeafStream, IFileSystemLeaf, IByteStream)