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180 lines
6.4 KiB
Python
180 lines
6.4 KiB
Python
"""Test largefile support on system where this makes sense.
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"""
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import os
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import stat
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import sys
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import unittest
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from test.support import TESTFN, requires, unlink
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import io # C implementation of io
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import _pyio as pyio # Python implementation of io
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# size of file to create (>2GB; 2GB == 2147483648 bytes)
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size = 2500000000
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class LargeFileTest:
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"""Test that each file function works as expected for large
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(i.e. > 2GB) files.
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"""
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def setUp(self):
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if os.path.exists(TESTFN):
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mode = 'r+b'
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else:
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mode = 'w+b'
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with self.open(TESTFN, mode) as f:
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current_size = os.fstat(f.fileno())[stat.ST_SIZE]
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if current_size == size+1:
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return
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if current_size == 0:
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f.write(b'z')
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f.seek(0)
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f.seek(size)
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f.write(b'a')
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f.flush()
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self.assertEqual(os.fstat(f.fileno())[stat.ST_SIZE], size+1)
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@classmethod
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def tearDownClass(cls):
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with cls.open(TESTFN, 'wb'):
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pass
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if not os.stat(TESTFN)[stat.ST_SIZE] == 0:
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raise cls.failureException('File was not truncated by opening '
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'with mode "wb"')
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def test_osstat(self):
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self.assertEqual(os.stat(TESTFN)[stat.ST_SIZE], size+1)
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def test_seek_read(self):
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with self.open(TESTFN, 'rb') as f:
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self.assertEqual(f.tell(), 0)
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self.assertEqual(f.read(1), b'z')
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self.assertEqual(f.tell(), 1)
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f.seek(0)
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self.assertEqual(f.tell(), 0)
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f.seek(0, 0)
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self.assertEqual(f.tell(), 0)
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f.seek(42)
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self.assertEqual(f.tell(), 42)
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f.seek(42, 0)
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self.assertEqual(f.tell(), 42)
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f.seek(42, 1)
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self.assertEqual(f.tell(), 84)
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f.seek(0, 1)
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self.assertEqual(f.tell(), 84)
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f.seek(0, 2) # seek from the end
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self.assertEqual(f.tell(), size + 1 + 0)
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f.seek(-10, 2)
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self.assertEqual(f.tell(), size + 1 - 10)
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f.seek(-size-1, 2)
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self.assertEqual(f.tell(), 0)
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f.seek(size)
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self.assertEqual(f.tell(), size)
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# the 'a' that was written at the end of file above
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self.assertEqual(f.read(1), b'a')
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f.seek(-size-1, 1)
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self.assertEqual(f.read(1), b'z')
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self.assertEqual(f.tell(), 1)
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def test_lseek(self):
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with self.open(TESTFN, 'rb') as f:
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self.assertEqual(os.lseek(f.fileno(), 0, 0), 0)
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self.assertEqual(os.lseek(f.fileno(), 42, 0), 42)
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self.assertEqual(os.lseek(f.fileno(), 42, 1), 84)
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self.assertEqual(os.lseek(f.fileno(), 0, 1), 84)
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self.assertEqual(os.lseek(f.fileno(), 0, 2), size+1+0)
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self.assertEqual(os.lseek(f.fileno(), -10, 2), size+1-10)
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self.assertEqual(os.lseek(f.fileno(), -size-1, 2), 0)
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self.assertEqual(os.lseek(f.fileno(), size, 0), size)
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# the 'a' that was written at the end of file above
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self.assertEqual(f.read(1), b'a')
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def test_truncate(self):
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with self.open(TESTFN, 'r+b') as f:
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if not hasattr(f, 'truncate'):
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raise unittest.SkipTest("open().truncate() not available "
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"on this system")
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f.seek(0, 2)
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# else we've lost track of the true size
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self.assertEqual(f.tell(), size+1)
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# Cut it back via seek + truncate with no argument.
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newsize = size - 10
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f.seek(newsize)
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f.truncate()
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self.assertEqual(f.tell(), newsize) # else pointer moved
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f.seek(0, 2)
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self.assertEqual(f.tell(), newsize) # else wasn't truncated
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# Ensure that truncate(smaller than true size) shrinks
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# the file.
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newsize -= 1
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f.seek(42)
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f.truncate(newsize)
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self.assertEqual(f.tell(), 42)
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f.seek(0, 2)
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self.assertEqual(f.tell(), newsize)
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# XXX truncate(larger than true size) is ill-defined
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# across platform; cut it waaaaay back
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f.seek(0)
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f.truncate(1)
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self.assertEqual(f.tell(), 0) # else pointer moved
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f.seek(0)
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self.assertEqual(len(f.read()), 1) # else wasn't truncated
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def test_seekable(self):
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# Issue #5016; seekable() can return False when the current position
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# is negative when truncated to an int.
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for pos in (2**31-1, 2**31, 2**31+1):
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with self.open(TESTFN, 'rb') as f:
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f.seek(pos)
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self.assertTrue(f.seekable())
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def setUpModule():
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try:
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import signal
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# The default handler for SIGXFSZ is to abort the process.
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# By ignoring it, system calls exceeding the file size resource
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# limit will raise OSError instead of crashing the interpreter.
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signal.signal(signal.SIGXFSZ, signal.SIG_IGN)
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except (ImportError, AttributeError):
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pass
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# On Windows and Mac OSX this test comsumes large resources; It
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# takes a long time to build the >2GB file and takes >2GB of disk
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# space therefore the resource must be enabled to run this test.
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# If not, nothing after this line stanza will be executed.
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if sys.platform[:3] == 'win' or sys.platform == 'darwin':
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requires('largefile',
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'test requires %s bytes and a long time to run' % str(size))
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else:
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# Only run if the current filesystem supports large files.
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# (Skip this test on Windows, since we now always support
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# large files.)
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f = open(TESTFN, 'wb', buffering=0)
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try:
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# 2**31 == 2147483648
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f.seek(2147483649)
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# Seeking is not enough of a test: you must write and flush, too!
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f.write(b'x')
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f.flush()
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except (OSError, OverflowError):
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raise unittest.SkipTest("filesystem does not have "
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"largefile support")
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finally:
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f.close()
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unlink(TESTFN)
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class CLargeFileTest(LargeFileTest, unittest.TestCase):
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open = staticmethod(io.open)
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class PyLargeFileTest(LargeFileTest, unittest.TestCase):
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open = staticmethod(pyio.open)
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def tearDownModule():
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unlink(TESTFN)
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if __name__ == '__main__':
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unittest.main()
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