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https://github.com/tahoe-lafs/tahoe-lafs.git
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133 lines
4.0 KiB
Python
133 lines
4.0 KiB
Python
import os
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from foolscap import Referenceable
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from twisted.application import service
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from twisted.python.failure import Failure
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from allmydata.util import idlib
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from amdlib.util.assertutil import precondition
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class NoSuchBucketError(Failure):
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pass
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class BucketStore(service.MultiService, Referenceable):
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def __init__(self, store_dir):
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precondition(os.path.isdir(store_dir))
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service.MultiService.__init__(self)
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self._store_dir = store_dir
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self._leases = set() # should do weakref dances.
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def _get_bucket_dir(self, verifierid):
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avid = idlib.b2a(verifierid)
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return os.path.join(self._store_dir, avid)
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def has_bucket(self, verifierid):
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return os.path.exists(self._get_bucket_dir(verifierid))
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def allocate_bucket(self, verifierid, bucket_num, size, leaser_credentials):
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bucket_dir = self._get_bucket_dir(verifierid)
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precondition(not os.path.exists(bucket_dir))
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precondition(isinstance(bucket_num, int))
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bucket = WriteBucket(bucket_dir, verifierid, bucket_num, size)
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bucket.set_leaser(leaser_credentials)
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lease = Lease(verifierid, leaser_credentials, bucket)
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self._leases.add(lease)
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return lease
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def get_bucket(self, verifierid):
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# for now, only returns those created by this process, in this run
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bucket_dir = self._get_bucket_dir(verifierid)
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if os.path.exists(bucket_dir):
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return BucketReader(ReadBucket(bucket_dir, verifierid))
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else:
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return NoSuchBucketError()
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class Lease(Referenceable):
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def __init__(self, verifierid, leaser, bucket):
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self._leaser = leaser
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self._verifierid = verifierid
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self._bucket = bucket
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def get_bucket(self):
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return self._bucket
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def remote_write(self, data):
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self._bucket.write(data)
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def remote_finalise(self):
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self._bucket.finalise()
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class BucketReader(Referenceable):
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def __init__(self, bucket):
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self._bucket = bucket
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def remote_get_bucket_num(self):
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return self._bucket.get_bucket_num()
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def remote_read(self):
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return self._bucket.read()
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class Bucket:
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def __init__(self, bucket_dir, verifierid):
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self._bucket_dir = bucket_dir
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self._verifierid = verifierid
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def _write_attr(self, name, val):
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f = file(os.path.join(self._bucket_dir, name), 'wb')
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f.write(val)
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f.close()
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def _read_attr(self, name):
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f = file(os.path.join(self._bucket_dir, name), 'rb')
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data = f.read()
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f.close()
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return data
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def is_complete(self):
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return os.path.exists(os.path.join(self._bucket_dir, 'closed'))
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class WriteBucket(Bucket):
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def __init__(self, bucket_dir, verifierid, bucket_num, size):
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Bucket.__init__(self, bucket_dir, verifierid)
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precondition(not os.path.exists(bucket_dir))
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os.mkdir(bucket_dir)
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self._size = size
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self._data = file(os.path.join(self._bucket_dir, 'data'), 'wb')
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self._bytes_written = 0
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self._write_attr('bucket_num', str(bucket_num))
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def set_leaser(self, leaser):
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self._write_attr('leases', leaser)
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def write(self, data):
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precondition(len(data) + self._bytes_written <= self._size)
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self._data.write(data)
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self._data.flush()
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self._bytes_written += len(data)
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def finalise(self):
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precondition(self._bytes_written == self._size)
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self._data.close()
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self._write_attr('closed', '')
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def is_complete(self):
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complete = Bucket.is_complete(self)
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if complete:
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_assert(os.path.getsize(os.path.join(self._bucket_dir, 'data')) == self._size)
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return complete
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class ReadBucket(Bucket):
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def __init__(self, bucket_dir, verifierid):
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Bucket.__init__(self, bucket_dir, verifierid)
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precondition(self.is_complete()) # implicitly asserts bucket_dir exists
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def get_bucket_num(self):
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return int(self._read_attr('bucket_num'))
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def read(self):
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return self._read_attr('data')
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