[Python-checkins] cpython (2.7): Issue #12213: Fix a buffering bug with interleaved reads and writes that
antoine.pitrou
python-checkins at python.org
Sat Aug 20 15:43:17 CEST 2011
http://hg.python.org/cpython/rev/cf2010e9f941
changeset: 71984:cf2010e9f941
branch: 2.7
parent: 71979:c816479f6aaf
user: Antoine Pitrou <solipsis at pitrou.net>
date: Sat Aug 20 15:40:58 2011 +0200
summary:
Issue #12213: Fix a buffering bug with interleaved reads and writes that
could appear on io.BufferedRandom streams.
files:
Lib/test/test_io.py | 45 +++++++++-
Misc/NEWS | 3 +
Modules/_io/bufferedio.c | 119 +++++++++++++-------------
3 files changed, 105 insertions(+), 62 deletions(-)
diff --git a/Lib/test/test_io.py b/Lib/test/test_io.py
--- a/Lib/test/test_io.py
+++ b/Lib/test/test_io.py
@@ -1367,15 +1367,18 @@
rw.seek(0, 0)
self.assertEqual(b"asdf", rw.read(4))
- rw.write(b"asdf")
+ rw.write(b"123f")
rw.seek(0, 0)
- self.assertEqual(b"asdfasdfl", rw.read())
+ self.assertEqual(b"asdf123fl", rw.read())
self.assertEqual(9, rw.tell())
rw.seek(-4, 2)
self.assertEqual(5, rw.tell())
rw.seek(2, 1)
self.assertEqual(7, rw.tell())
self.assertEqual(b"fl", rw.read(11))
+ rw.flush()
+ self.assertEqual(b"asdf123fl", raw.getvalue())
+
self.assertRaises(TypeError, rw.seek, 0.0)
def check_flush_and_read(self, read_func):
@@ -1520,6 +1523,44 @@
BufferedReaderTest.test_misbehaved_io(self)
BufferedWriterTest.test_misbehaved_io(self)
+ def test_interleaved_read_write(self):
+ # Test for issue #12213
+ with self.BytesIO(b'abcdefgh') as raw:
+ with self.tp(raw, 100) as f:
+ f.write(b"1")
+ self.assertEqual(f.read(1), b'b')
+ f.write(b'2')
+ self.assertEqual(f.read1(1), b'd')
+ f.write(b'3')
+ buf = bytearray(1)
+ f.readinto(buf)
+ self.assertEqual(buf, b'f')
+ f.write(b'4')
+ self.assertEqual(f.peek(1), b'h')
+ f.flush()
+ self.assertEqual(raw.getvalue(), b'1b2d3f4h')
+
+ with self.BytesIO(b'abc') as raw:
+ with self.tp(raw, 100) as f:
+ self.assertEqual(f.read(1), b'a')
+ f.write(b"2")
+ self.assertEqual(f.read(1), b'c')
+ f.flush()
+ self.assertEqual(raw.getvalue(), b'a2c')
+
+ def test_interleaved_readline_write(self):
+ with self.BytesIO(b'ab\ncdef\ng\n') as raw:
+ with self.tp(raw) as f:
+ f.write(b'1')
+ self.assertEqual(f.readline(), b'b\n')
+ f.write(b'2')
+ self.assertEqual(f.readline(), b'def\n')
+ f.write(b'3')
+ self.assertEqual(f.readline(), b'\n')
+ f.flush()
+ self.assertEqual(raw.getvalue(), b'1b\n2def\n3\n')
+
+
class CBufferedRandomTest(CBufferedReaderTest, CBufferedWriterTest, BufferedRandomTest):
tp = io.BufferedRandom
diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -40,6 +40,9 @@
Library
-------
+- Issue #12213: Fix a buffering bug with interleaved reads and writes that
+ could appear on io.BufferedRandom streams.
+
- Issue #12326: sys.platform is now always 'linux2' on Linux, even if Python
is compiled on Linux 3.
diff --git a/Modules/_io/bufferedio.c b/Modules/_io/bufferedio.c
--- a/Modules/_io/bufferedio.c
+++ b/Modules/_io/bufferedio.c
@@ -721,6 +721,28 @@
*/
static PyObject *
+buffered_flush_and_rewind_unlocked(buffered *self)
+{
+ PyObject *res;
+
+ res = _bufferedwriter_flush_unlocked(self, 0);
+ if (res == NULL)
+ return NULL;
+ Py_DECREF(res);
+
+ if (self->readable) {
+ /* Rewind the raw stream so that its position corresponds to
+ the current logical position. */
+ Py_off_t n;
+ n = _buffered_raw_seek(self, -RAW_OFFSET(self), 1);
+ _bufferedreader_reset_buf(self);
+ if (n == -1)
+ return NULL;
+ }
+ Py_RETURN_NONE;
+}
+
+static PyObject *
buffered_flush(buffered *self, PyObject *args)
{
PyObject *res;
@@ -730,16 +752,7 @@
if (!ENTER_BUFFERED(self))
return NULL;
- res = _bufferedwriter_flush_unlocked(self, 0);
- if (res != NULL && self->readable) {
- /* Rewind the raw stream so that its position corresponds to
- the current logical position. */
- Py_off_t n;
- n = _buffered_raw_seek(self, -RAW_OFFSET(self), 1);
- if (n == -1)
- Py_CLEAR(res);
- _bufferedreader_reset_buf(self);
- }
+ res = buffered_flush_and_rewind_unlocked(self);
LEAVE_BUFFERED(self)
return res;
@@ -760,7 +773,7 @@
return NULL;
if (self->writable) {
- res = _bufferedwriter_flush_unlocked(self, 1);
+ res = buffered_flush_and_rewind_unlocked(self);
if (res == NULL)
goto end;
Py_CLEAR(res);
@@ -795,19 +808,18 @@
if (!ENTER_BUFFERED(self))
return NULL;
res = _bufferedreader_read_all(self);
- LEAVE_BUFFERED(self)
}
else {
res = _bufferedreader_read_fast(self, n);
- if (res == Py_None) {
- Py_DECREF(res);
- if (!ENTER_BUFFERED(self))
- return NULL;
- res = _bufferedreader_read_generic(self, n);
- LEAVE_BUFFERED(self)
- }
+ if (res != Py_None)
+ return res;
+ Py_DECREF(res);
+ if (!ENTER_BUFFERED(self))
+ return NULL;
+ res = _bufferedreader_read_generic(self, n);
}
+ LEAVE_BUFFERED(self)
return res;
}
@@ -833,13 +845,6 @@
if (!ENTER_BUFFERED(self))
return NULL;
- if (self->writable) {
- res = _bufferedwriter_flush_unlocked(self, 1);
- if (res == NULL)
- goto end;
- Py_CLEAR(res);
- }
-
/* Return up to n bytes. If at least one byte is buffered, we
only return buffered bytes. Otherwise, we do one raw read. */
@@ -859,6 +864,13 @@
goto end;
}
+ if (self->writable) {
+ res = buffered_flush_and_rewind_unlocked(self);
+ if (res == NULL)
+ goto end;
+ Py_DECREF(res);
+ }
+
/* Fill the buffer from the raw stream, and copy it to the result. */
_bufferedreader_reset_buf(self);
r = _bufferedreader_fill_buffer(self);
@@ -881,24 +893,10 @@
static PyObject *
buffered_readinto(buffered *self, PyObject *args)
{
- PyObject *res = NULL;
-
CHECK_INITIALIZED(self)
- /* TODO: use raw.readinto() instead! */
- if (self->writable) {
- if (!ENTER_BUFFERED(self))
- return NULL;
- res = _bufferedwriter_flush_unlocked(self, 0);
- LEAVE_BUFFERED(self)
- if (res == NULL)
- goto end;
- Py_DECREF(res);
- }
- res = bufferediobase_readinto((PyObject *)self, args);
-
-end:
- return res;
+ /* TODO: use raw.readinto() (or a direct copy from our buffer) instead! */
+ return bufferediobase_readinto((PyObject *)self, args);
}
static PyObject *
@@ -936,12 +934,6 @@
goto end_unlocked;
/* Now we try to get some more from the raw stream */
- if (self->writable) {
- res = _bufferedwriter_flush_unlocked(self, 1);
- if (res == NULL)
- goto end;
- Py_CLEAR(res);
- }
chunks = PyList_New(0);
if (chunks == NULL)
goto end;
@@ -955,9 +947,16 @@
}
Py_CLEAR(res);
written += n;
+ self->pos += n;
if (limit >= 0)
limit -= n;
}
+ if (self->writable) {
+ PyObject *r = buffered_flush_and_rewind_unlocked(self);
+ if (r == NULL)
+ goto end;
+ Py_DECREF(r);
+ }
for (;;) {
_bufferedreader_reset_buf(self);
@@ -1126,20 +1125,11 @@
return NULL;
if (self->writable) {
- res = _bufferedwriter_flush_unlocked(self, 0);
+ res = buffered_flush_and_rewind_unlocked(self);
if (res == NULL)
goto end;
Py_CLEAR(res);
}
- if (self->readable) {
- if (pos == Py_None) {
- /* Rewind the raw stream so that its position corresponds to
- the current logical position. */
- if (_buffered_raw_seek(self, -RAW_OFFSET(self), 1) == -1)
- goto end;
- }
- _bufferedreader_reset_buf(self);
- }
res = PyObject_CallMethodObjArgs(self->raw, _PyIO_str_truncate, pos, NULL);
if (res == NULL)
goto end;
@@ -1341,17 +1331,18 @@
Py_DECREF(chunks);
return NULL;
}
+ self->pos += current_size;
}
- _bufferedreader_reset_buf(self);
/* We're going past the buffer's bounds, flush it */
if (self->writable) {
- res = _bufferedwriter_flush_unlocked(self, 1);
+ res = buffered_flush_and_rewind_unlocked(self);
if (res == NULL) {
Py_DECREF(chunks);
return NULL;
}
Py_CLEAR(res);
}
+ _bufferedreader_reset_buf(self);
while (1) {
if (data) {
if (PyList_Append(chunks, data) < 0) {
@@ -1434,6 +1425,14 @@
memcpy(out, self->buffer + self->pos, current_size);
remaining -= current_size;
written += current_size;
+ self->pos += current_size;
+ }
+ /* Flush the write buffer if necessary */
+ if (self->writable) {
+ PyObject *r = buffered_flush_and_rewind_unlocked(self);
+ if (r == NULL)
+ goto error;
+ Py_DECREF(r);
}
_bufferedreader_reset_buf(self);
while (remaining > 0) {
--
Repository URL: http://hg.python.org/cpython
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