"""Test largefile support on system where this makes sense. | |
""" | |
from __future__ import print_function | |
import os | |
import stat | |
import sys | |
import unittest | |
from test.test_support import run_unittest, TESTFN, verbose, requires, \ | |
unlink | |
import io # C implementation of io | |
import _pyio as pyio # Python implementation of io | |
try: | |
import signal | |
# The default handler for SIGXFSZ is to abort the process. | |
# By ignoring it, system calls exceeding the file size resource | |
# limit will raise IOError instead of crashing the interpreter. | |
oldhandler = signal.signal(signal.SIGXFSZ, signal.SIG_IGN) | |
except (ImportError, AttributeError): | |
pass | |
# create >2GB file (2GB = 2147483648 bytes) | |
size = 2500000000 | |
class LargeFileTest(unittest.TestCase): | |
"""Test that each file function works as expected for a large | |
(i.e. > 2GB, do we have to check > 4GB) files. | |
NOTE: the order of execution of the test methods is important! test_seek | |
must run first to create the test file. File cleanup must also be handled | |
outside the test instances because of this. | |
""" | |
def test_seek(self): | |
if verbose: | |
print('create large file via seek (may be sparse file) ...') | |
with self.open(TESTFN, 'wb') as f: | |
f.write(b'z') | |
f.seek(0) | |
f.seek(size) | |
f.write(b'a') | |
f.flush() | |
if verbose: | |
print('check file size with os.fstat') | |
self.assertEqual(os.fstat(f.fileno())[stat.ST_SIZE], size+1) | |
def test_osstat(self): | |
if verbose: | |
print('check file size with os.stat') | |
self.assertEqual(os.stat(TESTFN)[stat.ST_SIZE], size+1) | |
def test_seek_read(self): | |
if verbose: | |
print('play around with seek() and read() with the built largefile') | |
with self.open(TESTFN, 'rb') as f: | |
self.assertEqual(f.tell(), 0) | |
self.assertEqual(f.read(1), b'z') | |
self.assertEqual(f.tell(), 1) | |
f.seek(0) | |
self.assertEqual(f.tell(), 0) | |
f.seek(0, 0) | |
self.assertEqual(f.tell(), 0) | |
f.seek(42) | |
self.assertEqual(f.tell(), 42) | |
f.seek(42, 0) | |
self.assertEqual(f.tell(), 42) | |
f.seek(42, 1) | |
self.assertEqual(f.tell(), 84) | |
f.seek(0, 1) | |
self.assertEqual(f.tell(), 84) | |
f.seek(0, 2) # seek from the end | |
self.assertEqual(f.tell(), size + 1 + 0) | |
f.seek(-10, 2) | |
self.assertEqual(f.tell(), size + 1 - 10) | |
f.seek(-size-1, 2) | |
self.assertEqual(f.tell(), 0) | |
f.seek(size) | |
self.assertEqual(f.tell(), size) | |
# the 'a' that was written at the end of file above | |
self.assertEqual(f.read(1), b'a') | |
f.seek(-size-1, 1) | |
self.assertEqual(f.read(1), b'z') | |
self.assertEqual(f.tell(), 1) | |
def test_lseek(self): | |
if verbose: | |
print('play around with os.lseek() with the built largefile') | |
with self.open(TESTFN, 'rb') as f: | |
self.assertEqual(os.lseek(f.fileno(), 0, 0), 0) | |
self.assertEqual(os.lseek(f.fileno(), 42, 0), 42) | |
self.assertEqual(os.lseek(f.fileno(), 42, 1), 84) | |
self.assertEqual(os.lseek(f.fileno(), 0, 1), 84) | |
self.assertEqual(os.lseek(f.fileno(), 0, 2), size+1+0) | |
self.assertEqual(os.lseek(f.fileno(), -10, 2), size+1-10) | |
self.assertEqual(os.lseek(f.fileno(), -size-1, 2), 0) | |
self.assertEqual(os.lseek(f.fileno(), size, 0), size) | |
# the 'a' that was written at the end of file above | |
self.assertEqual(f.read(1), b'a') | |
def test_truncate(self): | |
if verbose: | |
print('try truncate') | |
with self.open(TESTFN, 'r+b') as f: | |
# this is already decided before start running the test suite | |
# but we do it anyway for extra protection | |
if not hasattr(f, 'truncate'): | |
raise unittest.SkipTest("open().truncate() not available on this system") | |
f.seek(0, 2) | |
# else we've lost track of the true size | |
self.assertEqual(f.tell(), size+1) | |
# Cut it back via seek + truncate with no argument. | |
newsize = size - 10 | |
f.seek(newsize) | |
f.truncate() | |
self.assertEqual(f.tell(), newsize) # else pointer moved | |
f.seek(0, 2) | |
self.assertEqual(f.tell(), newsize) # else wasn't truncated | |
# Ensure that truncate(smaller than true size) shrinks | |
# the file. | |
newsize -= 1 | |
f.seek(42) | |
f.truncate(newsize) | |
if self.new_io: | |
self.assertEqual(f.tell(), 42) | |
f.seek(0, 2) | |
self.assertEqual(f.tell(), newsize) | |
# XXX truncate(larger than true size) is ill-defined | |
# across platform; cut it waaaaay back | |
f.seek(0) | |
f.truncate(1) | |
if self.new_io: | |
self.assertEqual(f.tell(), 0) # else pointer moved | |
f.seek(0) | |
self.assertEqual(len(f.read()), 1) # else wasn't truncated | |
def test_seekable(self): | |
# Issue #5016; seekable() can return False when the current position | |
# is negative when truncated to an int. | |
if not self.new_io: | |
self.skipTest("builtin file doesn't have seekable()") | |
for pos in (2**31-1, 2**31, 2**31+1): | |
with self.open(TESTFN, 'rb') as f: | |
f.seek(pos) | |
self.assertTrue(f.seekable()) | |
def test_main(): | |
# On Windows and Mac OSX this test comsumes large resources; It | |
# takes a long time to build the >2GB file and takes >2GB of disk | |
# space therefore the resource must be enabled to run this test. | |
# If not, nothing after this line stanza will be executed. | |
if sys.platform[:3] == 'win' or sys.platform == 'darwin': | |
requires('largefile', | |
'test requires %s bytes and a long time to run' % str(size)) | |
else: | |
# Only run if the current filesystem supports large files. | |
# (Skip this test on Windows, since we now always support | |
# large files.) | |
f = open(TESTFN, 'wb', buffering=0) | |
try: | |
# 2**31 == 2147483648 | |
f.seek(2147483649) | |
# Seeking is not enough of a test: you must write and | |
# flush, too! | |
f.write(b'x') | |
f.flush() | |
except (IOError, OverflowError): | |
f.close() | |
unlink(TESTFN) | |
raise unittest.SkipTest("filesystem does not have largefile support") | |
else: | |
f.close() | |
suite = unittest.TestSuite() | |
for _open, prefix in [(io.open, 'C'), (pyio.open, 'Py'), | |
(open, 'Builtin')]: | |
class TestCase(LargeFileTest): | |
pass | |
TestCase.open = staticmethod(_open) | |
TestCase.new_io = _open is not open | |
TestCase.__name__ = prefix + LargeFileTest.__name__ | |
suite.addTest(TestCase('test_seek')) | |
suite.addTest(TestCase('test_osstat')) | |
suite.addTest(TestCase('test_seek_read')) | |
suite.addTest(TestCase('test_lseek')) | |
with _open(TESTFN, 'wb') as f: | |
if hasattr(f, 'truncate'): | |
suite.addTest(TestCase('test_truncate')) | |
suite.addTest(TestCase('test_seekable')) | |
unlink(TESTFN) | |
try: | |
run_unittest(suite) | |
finally: | |
unlink(TESTFN) | |
if __name__ == '__main__': | |
test_main() |