From 905a2ffe3e5445925a669ab433521ddb66cf1043 Mon Sep 17 00:00:00 2001 From: Antoine Pitrou Date: Sun, 31 Jan 2010 22:47:27 +0000 Subject: Merged revisions 77890 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r77890 | antoine.pitrou | 2010-01-31 23:26:04 +0100 (dim., 31 janv. 2010) | 7 lines - Issue #6939: Fix file I/O objects in the `io` module to keep the original file position when calling `truncate()`. It would previously change the file position to the given argument, which goes against the tradition of ftruncate() and other truncation APIs. Patch by Pascal Chambon. ........ --- Lib/_pyio.py | 8 ++---- Lib/test/test_fileio.py | 11 ++++++++ Lib/test/test_io.py | 20 +++++++++++-- Lib/test/test_largefile.py | 4 +-- Lib/test/test_memoryio.py | 5 ++-- Misc/ACKS | 1 + Misc/NEWS | 5 ++++ Modules/_io/bytesio.c | 3 +- Modules/_io/fileio.c | 70 +++++++++++++++++++++++++++++++++------------- Modules/_io/iobase.c | 4 +-- Modules/_io/stringio.c | 3 +- Modules/_io/textio.c | 10 +------ 12 files changed, 97 insertions(+), 47 deletions(-) diff --git a/Lib/_pyio.py b/Lib/_pyio.py index a4beb2b..8960ce9 100644 --- a/Lib/_pyio.py +++ b/Lib/_pyio.py @@ -856,7 +856,7 @@ class BytesIO(BufferedIOBase): elif pos < 0: raise ValueError("negative truncate position %r" % (pos,)) del self._buffer[pos:] - return self.seek(pos) + return pos def readable(self): return True @@ -1215,8 +1215,7 @@ class BufferedRandom(BufferedWriter, BufferedReader): if pos is None: pos = self.tell() # Use seek to flush the read buffer. - self.seek(pos) - return BufferedWriter.truncate(self) + return BufferedWriter.truncate(self, pos) def read(self, n=None): if n is None: @@ -1717,8 +1716,7 @@ class TextIOWrapper(TextIOBase): self.flush() if pos is None: pos = self.tell() - self.seek(pos) - return self.buffer.truncate() + return self.buffer.truncate(pos) def detach(self): if self.buffer is None: diff --git a/Lib/test/test_fileio.py b/Lib/test/test_fileio.py index d35549f..8348f6e 100644 --- a/Lib/test/test_fileio.py +++ b/Lib/test/test_fileio.py @@ -328,6 +328,17 @@ class OtherFileTests(unittest.TestCase): f.close() self.fail("no error for invalid mode: %s" % bad_mode) + def testTruncate(self): + f = _FileIO(TESTFN, 'w') + f.write(bytes(bytearray(range(10)))) + self.assertEqual(f.tell(), 10) + f.truncate(5) + self.assertEqual(f.tell(), 10) + self.assertEqual(f.seek(0, os.SEEK_END), 5) + f.truncate(15) + self.assertEqual(f.tell(), 5) + self.assertEqual(f.seek(0, os.SEEK_END), 15) + def testTruncateOnWindows(self): def bug801631(): # SF bug diff --git a/Lib/test/test_io.py b/Lib/test/test_io.py index fd7f404..fe1a2b8 100644 --- a/Lib/test/test_io.py +++ b/Lib/test/test_io.py @@ -229,6 +229,11 @@ class IOTest(unittest.TestCase): def write_ops(self, f): self.assertEqual(f.write(b"blah."), 5) + f.truncate(0) + self.assertEqual(f.tell(), 5) + f.seek(0) + + self.assertEqual(f.write(b"blah."), 5) self.assertEqual(f.seek(0), 0) self.assertEqual(f.write(b"Hello."), 6) self.assertEqual(f.tell(), 6) @@ -239,8 +244,9 @@ class IOTest(unittest.TestCase): self.assertEqual(f.write(b"h"), 1) self.assertEqual(f.seek(-1, 2), 13) self.assertEqual(f.tell(), 13) + self.assertEqual(f.truncate(12), 12) - self.assertEqual(f.tell(), 12) + self.assertEqual(f.tell(), 13) self.assertRaises(TypeError, f.seek, 0.0) def read_ops(self, f, buffered=False): @@ -285,7 +291,7 @@ class IOTest(unittest.TestCase): self.assertEqual(f.tell(), self.LARGE + 2) self.assertEqual(f.seek(0, 2), self.LARGE + 2) self.assertEqual(f.truncate(self.LARGE + 1), self.LARGE + 1) - self.assertEqual(f.tell(), self.LARGE + 1) + self.assertEqual(f.tell(), self.LARGE + 2) self.assertEqual(f.seek(0, 2), self.LARGE + 1) self.assertEqual(f.seek(-1, 2), self.LARGE) self.assertEqual(f.read(2), b"x") @@ -980,7 +986,7 @@ class BufferedWriterTest(unittest.TestCase, CommonBufferedTests): bufio = self.tp(raw, 8) bufio.write(b"abcdef") self.assertEqual(bufio.truncate(3), 3) - self.assertEqual(bufio.tell(), 3) + self.assertEqual(bufio.tell(), 6) with self.open(support.TESTFN, "rb", buffering=0) as f: self.assertEqual(f.read(), b"abc") @@ -1366,6 +1372,14 @@ class BufferedRandomTest(BufferedReaderTest, BufferedWriterTest): self.assertEqual(s, b"A" + b"B" * overwrite_size + b"A" * (9 - overwrite_size)) + def test_truncate_after_read_or_write(self): + raw = self.BytesIO(b"A" * 10) + bufio = self.tp(raw, 100) + self.assertEqual(bufio.read(2), b"AA") # the read buffer gets filled + self.assertEqual(bufio.truncate(), 2) + self.assertEqual(bufio.write(b"BB"), 2) # the write buffer increases + self.assertEqual(bufio.truncate(), 4) + def test_misbehaved_io(self): BufferedReaderTest.test_misbehaved_io(self) BufferedWriterTest.test_misbehaved_io(self) diff --git a/Lib/test/test_largefile.py b/Lib/test/test_largefile.py index 7fd3e0e..1c6297a 100644 --- a/Lib/test/test_largefile.py +++ b/Lib/test/test_largefile.py @@ -122,14 +122,14 @@ class LargeFileTest(unittest.TestCase): newsize -= 1 f.seek(42) f.truncate(newsize) - self.assertEqual(f.tell(), newsize) # else wasn't truncated + 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) - self.assertEqual(f.tell(), 1) # else pointer moved + self.assertEqual(f.tell(), 0) # else pointer moved f.seek(0) self.assertEqual(len(f.read()), 1) # else wasn't truncated diff --git a/Lib/test/test_memoryio.py b/Lib/test/test_memoryio.py index 9777631..99dfe6c 100644 --- a/Lib/test/test_memoryio.py +++ b/Lib/test/test_memoryio.py @@ -73,7 +73,7 @@ class MemoryTestMixin: self.assertEqual(f.seek(0), 0) self.assertEqual(f.write(t("h")), 1) self.assertEqual(f.truncate(12), 12) - self.assertEqual(f.tell(), 12) + self.assertEqual(f.tell(), 1) def test_write(self): buf = self.buftype("hello world\n") @@ -121,7 +121,8 @@ class MemoryTestMixin: self.assertEqual(memio.getvalue(), buf[:6]) self.assertEqual(memio.truncate(4), 4) self.assertEqual(memio.getvalue(), buf[:4]) - self.assertEqual(memio.tell(), 4) + self.assertEqual(memio.tell(), 6) + memio.seek(0, 2) memio.write(buf) self.assertEqual(memio.getvalue(), buf[:4] + buf) pos = memio.tell() diff --git a/Misc/ACKS b/Misc/ACKS index 3ee0d9f..b991960 100644 --- a/Misc/ACKS +++ b/Misc/ACKS @@ -123,6 +123,7 @@ Donn Cave Charles Cazabon Per Cederqvist Octavian Cerna +Pascal Chambon Hye-Shik Chang Jeffrey Chang Mitch Chapman diff --git a/Misc/NEWS b/Misc/NEWS index 0abe5c2..02cdfbe 100644 --- a/Misc/NEWS +++ b/Misc/NEWS @@ -239,6 +239,11 @@ C-API Library ------- +- Issue #6939: Fix file I/O objects in the `io` module to keep the original + file position when calling `truncate()`. It would previously change the + file position to the given argument, which goes against the tradition of + ftruncate() and other truncation APIs. Patch by Pascal Chambon. + - Issue #7610: Reworked implementation of the internal :class:`zipfile.ZipExtFile` class used to represent files stored inside an archive. The new implementation is significantly faster and can diff --git a/Modules/_io/bytesio.c b/Modules/_io/bytesio.c index 5ca878d..1482d82 100644 --- a/Modules/_io/bytesio.c +++ b/Modules/_io/bytesio.c @@ -412,7 +412,7 @@ PyDoc_STRVAR(truncate_doc, "truncate([size]) -> int. Truncate the file to at most size bytes.\n" "\n" "Size defaults to the current file position, as returned by tell().\n" -"Returns the new size. Imply an absolute seek to the position size."); +"The current file position is unchanged. Returns the new size.\n"); static PyObject * bytesio_truncate(bytesio *self, PyObject *args) @@ -451,7 +451,6 @@ bytesio_truncate(bytesio *self, PyObject *args) if (resize_buffer(self, size) < 0) return NULL; } - self->pos = size; return PyLong_FromSsize_t(size); } diff --git a/Modules/_io/fileio.c b/Modules/_io/fileio.c index f02fe8a..a785e79 100644 --- a/Modules/_io/fileio.c +++ b/Modules/_io/fileio.c @@ -758,8 +758,10 @@ fileio_tell(fileio *self, PyObject *args) static PyObject * fileio_truncate(fileio *self, PyObject *args) { - PyObject *posobj = NULL; + PyObject *posobj = NULL; /* the new size wanted by the user */ +#ifndef MS_WINDOWS Py_off_t pos; +#endif int ret; int fd; @@ -774,58 +776,86 @@ fileio_truncate(fileio *self, PyObject *args) if (posobj == Py_None || posobj == NULL) { /* Get the current position. */ - posobj = portable_lseek(fd, NULL, 1); - if (posobj == NULL) + posobj = portable_lseek(fd, NULL, 1); + if (posobj == NULL) return NULL; - } - else { - /* Move to the position to be truncated. */ - posobj = portable_lseek(fd, posobj, 0); - } - if (posobj == NULL) - return NULL; - -#if defined(HAVE_LARGEFILE_SUPPORT) - pos = PyLong_AsLongLong(posobj); -#else - pos = PyLong_AsLong(posobj); -#endif - if (pos == -1 && PyErr_Occurred()) - return NULL; + } + else { + Py_INCREF(posobj); + } #ifdef MS_WINDOWS /* MS _chsize doesn't work if newsize doesn't fit in 32 bits, so don't even try using it. */ { + PyObject *oldposobj, *tempposobj; HANDLE hFile; + + /* we save the file pointer position */ + oldposobj = portable_lseek(fd, NULL, 1); + if (oldposobj == NULL) { + Py_DECREF(posobj); + return NULL; + } + + /* we then move to the truncation position */ + tempposobj = portable_lseek(fd, posobj, 0); + if (tempposobj == NULL) { + Py_DECREF(oldposobj); + Py_DECREF(posobj); + return NULL; + } + Py_DECREF(tempposobj); /* Truncate. Note that this may grow the file! */ Py_BEGIN_ALLOW_THREADS errno = 0; hFile = (HANDLE)_get_osfhandle(fd); - ret = hFile == (HANDLE)-1; + ret = hFile == (HANDLE)-1; /* testing for INVALID_HANDLE value */ if (ret == 0) { ret = SetEndOfFile(hFile) == 0; if (ret) errno = EACCES; } Py_END_ALLOW_THREADS + + /* we restore the file pointer position in any case */ + tempposobj = portable_lseek(fd, oldposobj, 0); + Py_DECREF(oldposobj); + if (tempposobj == NULL) { + Py_DECREF(posobj); + return NULL; + } + Py_DECREF(tempposobj); } #else + +#if defined(HAVE_LARGEFILE_SUPPORT) + pos = PyLong_AsLongLong(posobj); +#else + pos = PyLong_AsLong(posobj); +#endif + if (PyErr_Occurred()){ + Py_DECREF(posobj); + return NULL; + } + Py_BEGIN_ALLOW_THREADS errno = 0; ret = ftruncate(fd, pos); Py_END_ALLOW_THREADS + #endif /* !MS_WINDOWS */ if (ret != 0) { + Py_DECREF(posobj); PyErr_SetFromErrno(PyExc_IOError); return NULL; } return posobj; } -#endif +#endif /* HAVE_FTRUNCATE */ static char * mode_string(fileio *self) diff --git a/Modules/_io/iobase.c b/Modules/_io/iobase.c index d4757ed..271a41e 100644 --- a/Modules/_io/iobase.c +++ b/Modules/_io/iobase.c @@ -102,8 +102,8 @@ iobase_tell(PyObject *self, PyObject *args) PyDoc_STRVAR(iobase_truncate_doc, "Truncate file to size bytes.\n" "\n" - "Size defaults to the current IO position as reported by tell(). Return\n" - "the new size."); + "File pointer is left unchanged. Size defaults to the current IO\n" + "position as reported by tell(). Returns the new size."); static PyObject * iobase_truncate(PyObject *self, PyObject *args) diff --git a/Modules/_io/stringio.c b/Modules/_io/stringio.c index c19c4c0..13e3b58 100644 --- a/Modules/_io/stringio.c +++ b/Modules/_io/stringio.c @@ -350,7 +350,7 @@ PyDoc_STRVAR(stringio_truncate_doc, "Truncate size to pos.\n" "\n" "The pos argument defaults to the current file position, as\n" - "returned by tell(). Imply an absolute seek to pos.\n" + "returned by tell(). The current file position is unchanged.\n" "Returns the new absolute position.\n"); static PyObject * @@ -390,7 +390,6 @@ stringio_truncate(stringio *self, PyObject *args) return NULL; self->string_size = size; } - self->pos = size; return PyLong_FromSsize_t(size); } diff --git a/Modules/_io/textio.c b/Modules/_io/textio.c index ba28d59..89d922c 100644 --- a/Modules/_io/textio.c +++ b/Modules/_io/textio.c @@ -2318,15 +2318,7 @@ textiowrapper_truncate(textio *self, PyObject *args) return NULL; Py_DECREF(res); - if (pos != Py_None) { - res = PyObject_CallMethodObjArgs((PyObject *) self, - _PyIO_str_seek, pos, NULL); - if (res == NULL) - return NULL; - Py_DECREF(res); - } - - return PyObject_CallMethodObjArgs(self->buffer, _PyIO_str_truncate, NULL); + return PyObject_CallMethodObjArgs(self->buffer, _PyIO_str_truncate, pos, NULL); } static PyObject * -- cgit v0.12