| """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() |