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Revert "bpo-17852: Maintain a list of BufferedWriter objects. Flush them on exit."#3337

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Merged
nascheme merged 1 commit into from
Sep 5, 2017
Merged

Revert "bpo-17852: Maintain a list of BufferedWriter objects. Flush them on exit." #3337

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24 changes: 0 additions & 24 deletions Lib/_pyio.py
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Original file line numberDiff line numberDiff line change
Expand Up@@ -1185,7 +1185,6 @@ def __init__(self, raw, buffer_size=DEFAULT_BUFFER_SIZE):
self.buffer_size = buffer_size
self._write_buf = bytearray()
self._write_lock = Lock()
_register_writer(self)

def writable(self):
return self.raw.writable()
Expand DownExpand Up@@ -2575,26 +2574,3 @@ def encoding(self):
def detach(self):
# This doesn't make sense on StringIO.
self._unsupported("detach")


# ____________________________________________________________

import atexit, weakref

_all_writers = weakref.WeakSet()

def _register_writer(w):
# keep weak-ref to buffered writer
_all_writers.add(w)

def _flush_all_writers():
# Ensure all buffered writers are flushed before proceeding with
# normal shutdown. Otherwise, if the underlying file objects get
# finalized before the buffered writer wrapping it then any buffered
# data will be lost.
for w in _all_writers:
try:
w.flush()
except:
pass
atexit.register(_flush_all_writers)
2 changes: 0 additions & 2 deletions Misc/NEWS.d/next/Core and Builtins/2017-09-04-12-46-25.bpo-17852.OxAtCg.rst
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2 changes: 0 additions & 2 deletions Modules/_io/_iomodule.c
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Expand Up@@ -766,8 +766,6 @@ PyInit__io(void)
!(_PyIO_empty_bytes = PyBytes_FromStringAndSize(NULL, 0)))
goto fail;

_Py_PyAtExit(_PyIO_atexit_flush);

state->initialized = 1;

return m;
Expand Down
2 changes: 0 additions & 2 deletions Modules/_io/_iomodule.h
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Expand Up@@ -183,5 +183,3 @@ extern PyObject *_PyIO_empty_str;
extern PyObject *_PyIO_empty_bytes;

extern PyTypeObject _PyBytesIOBuffer_Type;

extern void _PyIO_atexit_flush(void);
46 changes: 1 addition & 45 deletions Modules/_io/bufferedio.c
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Expand Up@@ -196,7 +196,7 @@ bufferediobase_write(PyObject *self, PyObject *args)
}


typedef struct _buffered {
typedef struct{
PyObject_HEAD

PyObject *raw;
Expand DownExpand Up@@ -240,18 +240,8 @@ typedef struct _buffered{

PyObject *dict;
PyObject *weakreflist;

/* a doubly-linked chained list of "buffered" objects that need to
be flushed when the process exits */
struct _buffered *next, *prev;
} buffered;

/* the actual list of buffered objects */
static buffered buffer_list_end ={
.next = &buffer_list_end,
.prev = &buffer_list_end
};

/*
Implementation notes:

Expand DownExpand Up@@ -396,15 +386,6 @@ _enter_buffered_busy(buffered *self)
(self->buffer_size * (size / self->buffer_size)))


static void
remove_from_linked_list(buffered *self)
{
self->next->prev = self->prev;
self->prev->next = self->next;
self->prev = NULL;
self->next = NULL;
}

static void
buffered_dealloc(buffered *self)
{
Expand All@@ -413,8 +394,6 @@ buffered_dealloc(buffered *self)
return;
_PyObject_GC_UNTRACK(self);
self->ok = 0;
if (self->next != NULL)
remove_from_linked_list(self);
if (self->weakreflist != NULL)
PyObject_ClearWeakRefs((PyObject *)self);
Py_CLEAR(self->raw);
Expand DownExpand Up@@ -1838,33 +1817,10 @@ _io_BufferedWriter___init___impl(buffered *self, PyObject *raw,
self->fast_closed_checks = (Py_TYPE(self) == &PyBufferedWriter_Type &&
Py_TYPE(raw) == &PyFileIO_Type);

if (self->next == NULL){
self->prev = &buffer_list_end;
self->next = buffer_list_end.next;
buffer_list_end.next->prev = self;
buffer_list_end.next = self;
}

self->ok = 1;
return 0;
}

/*
* Ensure all buffered writers are flushed before proceeding with
* normal shutdown. Otherwise, if the underlying file objects get
* finalized before the buffered writer wrapping it then any buffered
* data will be lost.
*/
void _PyIO_atexit_flush(void)
{
while (buffer_list_end.next != &buffer_list_end){
buffered *buf = buffer_list_end.next;
remove_from_linked_list(buf);
buffered_flush(buf, NULL);
PyErr_Clear();
}
}

static Py_ssize_t
_bufferedwriter_raw_write(buffered *self, char *start, Py_ssize_t len)
{
Expand Down