add seek() to CompressingFileReader

Code Issues Proposed changes

Change-Id: I33d9119684497b53101db3bc380953e86bdf25f0

This commit is contained in:

Greg Lange

2013年09月17日 19:24:24 +00:00

parent 8e48dd6b7f

commit 285a3a88a1

2 changed files with 42 additions and 4 deletions

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20
swift/common/internal_client.py

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@@ -56,14 +56,23 @@ class CompressingFileReader(object):

def __init__(self, file_obj, compresslevel=9, chunk_size=4096):

self._f = file_obj

self.compresslevel = compresslevel

self.chunk_size = chunk_size

self.set_initial_state()

def set_initial_state(self):

"""

Sets the object to the state needed for the first read.

"""

self._f.seek(0)

self._compressor = compressobj(

compresslevel, zlib.DEFLATED, -zlib.MAX_WBITS, zlib.DEF_MEM_LEVEL,

0)

self.compresslevel, zlib.DEFLATED, -zlib.MAX_WBITS,

zlib.DEF_MEM_LEVEL, 0)

self.done = False

self.first = True

self.crc32 = 0

self.total_size = 0

self.chunk_size = chunk_size

def read(self, *a, **kw):

"""

@@ -105,6 +114,11 @@ class CompressingFileReader(object):

return chunk

raise StopIteration

def seek(self, offset, whence=0):

if not (offset == 0 and whence == 0):

raise NotImplementedError('Seek implemented on offset 0 only')

self.set_initial_state()

class InternalClient(object):

"""

26
test/unit/common/test_internal_client.py

View File

@@ -141,7 +141,8 @@ class TestCompressingfileReader(unittest.TestCase):

def test_read(self):

exp_data = 'abcdefghijklmnopqrstuvwxyz'

fobj = internal_client.CompressingFileReader(StringIO(exp_data))

fobj = internal_client.CompressingFileReader(

StringIO(exp_data), chunk_size=5)

data = ''

d = zlib.decompressobj(16 + zlib.MAX_WBITS)

@@ -150,6 +151,29 @@ class TestCompressingfileReader(unittest.TestCase):

self.assertEquals(exp_data, data)

def test_seek(self):

exp_data = 'abcdefghijklmnopqrstuvwxyz'

fobj = internal_client.CompressingFileReader(

StringIO(exp_data), chunk_size=5)

# read a couple of chunks only

for _ in range(2):

fobj.read()

# read whole thing after seek and check data

fobj.seek(0)

data = ''

d = zlib.decompressobj(16 + zlib.MAX_WBITS)

for chunk in fobj.read():

data += d.decompress(chunk)

self.assertEquals(exp_data, data)

def test_seek_not_implemented_exception(self):

fobj = internal_client.CompressingFileReader(

StringIO(''), chunk_size=5)

self.assertRaises(NotImplementedError, fobj.seek, 10)

self.assertRaises(NotImplementedError, fobj.seek, 0, 10)

class TestInternalClient(unittest.TestCase):

def test_init(self):