cpython/Modules/_io/bufferedio.c at pythoncapi · pythoncapi/cpython · GitHub

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An implementation of Buffered I/O as defined by PEP 3116 - "New I/O"

Classes defined here: BufferedIOBase, BufferedReader, BufferedWriter,

BufferedRandom.

Written by Amaury Forgeot d'Arc and Antoine Pitrou

#define PY_SSIZE_T_CLEAN

#include "Python.h"

#include "internal/pystate.h"

#include "structmember.h"

#include "pythread.h"

#include "_iomodule.h"

/*[clinic input]

module _io

class _io._BufferedIOBase "PyObject *" "&PyBufferedIOBase_Type"

class _io._Buffered "buffered *" "&PyBufferedIOBase_Type"

class _io.BufferedReader "buffered *" "&PyBufferedReader_Type"

class _io.BufferedWriter "buffered *" "&PyBufferedWriter_Type"

class _io.BufferedRWPair "rwpair *" "&PyBufferedRWPair_Type"

class _io.BufferedRandom "buffered *" "&PyBufferedRandom_Type"

[clinic start generated code]*/

/*[clinic end generated code: output=da39a3ee5e6b4b0d input=59460b9c5639984d]*/

_Py_IDENTIFIER(close);

_Py_IDENTIFIER(_dealloc_warn);

_Py_IDENTIFIER(flush);

_Py_IDENTIFIER(isatty);

_Py_IDENTIFIER(mode);

_Py_IDENTIFIER(name);

_Py_IDENTIFIER(peek);

_Py_IDENTIFIER(read);

_Py_IDENTIFIER(read1);

_Py_IDENTIFIER(readable);

_Py_IDENTIFIER(readinto);

_Py_IDENTIFIER(readinto1);

_Py_IDENTIFIER(writable);

_Py_IDENTIFIER(write);

* BufferedIOBase class, inherits from IOBase.

PyDoc_STRVAR(bufferediobase_doc,

"Base class for buffered IO objects.\n"

"\n"

"The main difference with RawIOBase is that the read() method\n"

"supports omitting the size argument, and does not have a default\n"

"implementation that defers to readinto().\n"

"\n"

"In addition, read(), readinto() and write() may raise\n"

"BlockingIOError if the underlying raw stream is in non-blocking\n"

"mode and not ready; unlike their raw counterparts, they will never\n"

"return None.\n"

"\n"

"A typical implementation should not inherit from a RawIOBase\n"

"implementation, but wrap one.\n"

);

static PyObject *

_bufferediobase_readinto_generic(PyObject *self, Py_buffer *buffer, char readinto1)

{

Py_ssize_t len;

PyObject *data;

data = _PyObject_CallMethodId(self,

readinto1 ? &PyId_read1 : &PyId_read,

"n", buffer->len);

if (data == NULL)

return NULL;

if (!PyBytes_Check(data)) {

Py_DECREF(data);

PyErr_SetString(PyExc_TypeError, "read() should return bytes");

return NULL;

}

len = PyBytes_GET_SIZE(data);

if (len > buffer->len) {

PyErr_Format(PyExc_ValueError,

"read() returned too much data: "

"%zd bytes requested, %zd returned",

buffer->len, len);

Py_DECREF(data);

return NULL;

}

memcpy(buffer->buf, PyBytes_AS_STRING(data), len);

Py_DECREF(data);

return PyLong_FromSsize_t(len);

}

/*[clinic input]

_io._BufferedIOBase.readinto

buffer: Py_buffer(accept={rwbuffer})

[clinic start generated code]*/

static PyObject *

_io__BufferedIOBase_readinto_impl(PyObject *self, Py_buffer *buffer)

/*[clinic end generated code: output=8c8cda6684af8038 input=00a6b9a38f29830a]*/

{

return _bufferediobase_readinto_generic(self, buffer, 0);

}

/*[clinic input]

_io._BufferedIOBase.readinto1

buffer: Py_buffer(accept={rwbuffer})

[clinic start generated code]*/

static PyObject *

_io__BufferedIOBase_readinto1_impl(PyObject *self, Py_buffer *buffer)

/*[clinic end generated code: output=358623e4fd2b69d3 input=ebad75b4aadfb9be]*/

{

return _bufferediobase_readinto_generic(self, buffer, 1);

}

static PyObject *

bufferediobase_unsupported(const char *message)

{

_PyIO_State *state = IO_STATE();

if (state != NULL)

PyErr_SetString(state->unsupported_operation, message);

return NULL;

}

/*[clinic input]

_io._BufferedIOBase.detach

Disconnect this buffer from its underlying raw stream and return it.

After the raw stream has been detached, the buffer is in an unusable

state.

[clinic start generated code]*/

static PyObject *

_io__BufferedIOBase_detach_impl(PyObject *self)

/*[clinic end generated code: output=754977c8d10ed88c input=822427fb58fe4169]*/

{

return bufferediobase_unsupported("detach");

}

PyDoc_STRVAR(bufferediobase_read_doc,

"Read and return up to n bytes.\n"

"\n"

"If the argument is omitted, None, or negative, reads and\n"

"returns all data until EOF.\n"

"\n"

"If the argument is positive, and the underlying raw stream is\n"

"not 'interactive', multiple raw reads may be issued to satisfy\n"

"the byte count (unless EOF is reached first). But for\n"

"interactive raw streams (as well as sockets and pipes), at most\n"

"one raw read will be issued, and a short result does not imply\n"

"that EOF is imminent.\n"

"\n"

"Returns an empty bytes object on EOF.\n"

"\n"

"Returns None if the underlying raw stream was open in non-blocking\n"

"mode and no data is available at the moment.\n");

static PyObject *

bufferediobase_read(PyObject *self, PyObject *args)

{

return bufferediobase_unsupported("read");

}

PyDoc_STRVAR(bufferediobase_read1_doc,

"Read and return up to n bytes, with at most one read() call\n"

"to the underlying raw stream. A short result does not imply\n"

"that EOF is imminent.\n"

"\n"

"Returns an empty bytes object on EOF.\n");

static PyObject *

bufferediobase_read1(PyObject *self, PyObject *args)

{

return bufferediobase_unsupported("read1");

}

PyDoc_STRVAR(bufferediobase_write_doc,

"Write the given buffer to the IO stream.\n"

"\n"

"Returns the number of bytes written, which is always the length of b\n"

"in bytes.\n"

"\n"

"Raises BlockingIOError if the buffer is full and the\n"

"underlying raw stream cannot accept more data at the moment.\n");

static PyObject *

bufferediobase_write(PyObject *self, PyObject *args)

{

return bufferediobase_unsupported("write");

}

typedef struct {

PyObject_HEAD

PyObject *raw;

int ok; /* Initialized? */

int detached;

int readable;

int writable;

char finalizing;

/* True if this is a vanilla Buffered object (rather than a user derived

class) *and* the raw stream is a vanilla FileIO object. */

int fast_closed_checks;

/* Absolute position inside the raw stream (-1 if unknown). */

Py_off_t abs_pos;

/* A static buffer of size `buffer_size` */

char *buffer;

/* Current logical position in the buffer. */

Py_off_t pos;

/* Position of the raw stream in the buffer. */

Py_off_t raw_pos;

/* Just after the last buffered byte in the buffer, or -1 if the buffer

isn't ready for reading. */

Py_off_t read_end;

/* Just after the last byte actually written */

Py_off_t write_pos;

/* Just after the last byte waiting to be written, or -1 if the buffer

isn't ready for writing. */

Py_off_t write_end;

PyThread_type_lock lock;

volatile unsigned long owner;

Py_ssize_t buffer_size;

Py_ssize_t buffer_mask;

PyObject *dict;

PyObject *weakreflist;

} buffered;

Implementation notes:

* BufferedReader, BufferedWriter and BufferedRandom try to share most

methods (this is helped by the members `readable` and `writable`, which

are initialized in the respective constructors)

* They also share a single buffer for reading and writing. This enables

interleaved reads and writes without flushing. It also makes the logic

a bit trickier to get right.

* The absolute position of the raw stream is cached, if possible, in the

`abs_pos` member. It must be updated every time an operation is done

on the raw stream. If not sure, it can be reinitialized by calling

_buffered_raw_tell(), which queries the raw stream (_buffered_raw_seek()

also does it). To read it, use RAW_TELL().

* Three helpers, _bufferedreader_raw_read, _bufferedwriter_raw_write and

_bufferedwriter_flush_unlocked do a lot of useful housekeeping.

NOTE: we should try to maintain block alignment of reads and writes to the

raw stream (according to the buffer size), but for now it is only done

in read() and friends.

/* These macros protect the buffered object against concurrent operations. */

static int

_enter_buffered_busy(buffered *self)

{

int relax_locking;

PyLockStatus st;

if (self->owner == PyThread_get_thread_ident()) {

PyErr_Format(PyExc_RuntimeError,

"reentrant call inside %R", self);

return 0;

}

relax_locking = _Py_IsFinalizing();

Py_BEGIN_ALLOW_THREADS

if (!relax_locking)

st = PyThread_acquire_lock(self->lock, 1);

else {

/* When finalizing, we don't want a deadlock to happen with daemon

* threads abruptly shut down while they owned the lock.

* Therefore, only wait for a grace period (1 s.).

* Note that non-daemon threads have already exited here, so this

* shouldn't affect carefully written threaded I/O code.

st = PyThread_acquire_lock_timed(self->lock, (PY_TIMEOUT_T)1e6, 0);

}

Py_END_ALLOW_THREADS

if (relax_locking && st != PY_LOCK_ACQUIRED) {

PyObject *msgobj = PyUnicode_FromFormat(

"could not acquire lock for %A at interpreter "

"shutdown, possibly due to daemon threads",

(PyObject *) self);

const char *msg = PyUnicode_AsUTF8(msgobj);

Py_FatalError(msg);

}

return 1;

}

#define ENTER_BUFFERED(self) \

( (PyThread_acquire_lock(self->lock, 0) ? \

1 : _enter_buffered_busy(self)) \

&& (self->owner = PyThread_get_thread_ident(), 1) )

#define LEAVE_BUFFERED(self) \

do { \

self->owner = 0; \

PyThread_release_lock(self->lock); \

} while(0);

#define CHECK_INITIALIZED(self) \

if (self->ok <= 0) { \

if (self->detached) { \

PyErr_SetString(PyExc_ValueError, \

"raw stream has been detached"); \

} else { \

PyErr_SetString(PyExc_ValueError, \

"I/O operation on uninitialized object"); \

} \

return NULL; \

}

#define CHECK_INITIALIZED_INT(self) \

if (self->ok <= 0) { \

if (self->detached) { \

PyErr_SetString(PyExc_ValueError, \

"raw stream has been detached"); \

} else { \

PyErr_SetString(PyExc_ValueError, \

"I/O operation on uninitialized object"); \

} \

return -1; \

}

#define IS_CLOSED(self) \

(!self->buffer || \

(self->fast_closed_checks \

? _PyFileIO_closed(self->raw) \

: buffered_closed(self)))

#define CHECK_CLOSED(self, error_msg) \

if (IS_CLOSED(self)) { \

PyErr_SetString(PyExc_ValueError, error_msg); \

return NULL; \

}

#define VALID_READ_BUFFER(self) \

(self->readable && self->read_end != -1)

#define VALID_WRITE_BUFFER(self) \

(self->writable && self->write_end != -1)

#define ADJUST_POSITION(self, _new_pos) \

do { \

self->pos = _new_pos; \

if (VALID_READ_BUFFER(self) && self->read_end < self->pos) \

self->read_end = self->pos; \

} while(0)

#define READAHEAD(self) \

((self->readable && VALID_READ_BUFFER(self)) \

? (self->read_end - self->pos) : 0)

#define RAW_OFFSET(self) \

(((VALID_READ_BUFFER(self) || VALID_WRITE_BUFFER(self)) \

&& self->raw_pos >= 0) ? self->raw_pos - self->pos : 0)

#define RAW_TELL(self) \

(self->abs_pos != -1 ? self->abs_pos : _buffered_raw_tell(self))

#define MINUS_LAST_BLOCK(self, size) \

(self->buffer_mask ? \

(size & ~self->buffer_mask) : \

(self->buffer_size * (size / self->buffer_size)))

static void

buffered_dealloc(buffered *self)

{

self->finalizing = 1;

if (_PyIOBase_finalize((PyObject *) self) < 0)

return;

_PyObject_GC_UNTRACK(self);

self->ok = 0;

if (self->weakreflist != NULL)

PyObject_ClearWeakRefs((PyObject *)self);

Py_CLEAR(self->raw);

if (self->buffer) {

PyMem_Free(self->buffer);

self->buffer = NULL;

}

if (self->lock) {

PyThread_free_lock(self->lock);

self->lock = NULL;

}

Py_CLEAR(self->dict);

Py_TYPE(self)->tp_free((PyObject *)self);

}

static PyObject *

buffered_sizeof(buffered *self, PyObject *Py_UNUSED(ignored))

{

Py_ssize_t res;

res = _PyObject_SIZE(Py_TYPE(self));

if (self->buffer)

res += self->buffer_size;

return PyLong_FromSsize_t(res);

}

static int

buffered_traverse(buffered *self, visitproc visit, void *arg)

{

Py_VISIT(self->raw);

Py_VISIT(self->dict);

return 0;

}

static int

buffered_clear(buffered *self)

{

self->ok = 0;

Py_CLEAR(self->raw);

Py_CLEAR(self->dict);

return 0;

}

/* Because this can call arbitrary code, it shouldn't be called when

the refcount is 0 (that is, not directly from tp_dealloc unless

the refcount has been temporarily re-incremented). */

static PyObject *

buffered_dealloc_warn(buffered *self, PyObject *source)

{

if (self->ok && self->raw) {

PyObject *r;

r = _PyObject_CallMethodIdObjArgs(self->raw, &PyId__dealloc_warn,

source, NULL);

if (r)

Py_DECREF(r);

else

PyErr_Clear();

}

Py_RETURN_NONE;

}

* _BufferedIOMixin methods

* This is not a class, just a collection of methods that will be reused

* by BufferedReader and BufferedWriter

/* Flush and close */

static PyObject *

buffered_simple_flush(buffered *self, PyObject *args)

{

CHECK_INITIALIZED(self)

return PyObject_CallMethodObjArgs(self->raw, _PyIO_str_flush, NULL);

}

static int

buffered_closed(buffered *self)

{

int closed;

PyObject *res;

CHECK_INITIALIZED_INT(self)

res = PyObject_GetAttr(self->raw, _PyIO_str_closed);

if (res == NULL)

return -1;

closed = PyObject_IsTrue(res);

Py_DECREF(res);

return closed;

}

static PyObject *

buffered_closed_get(buffered *self, void *context)

{

CHECK_INITIALIZED(self)

return PyObject_GetAttr(self->raw, _PyIO_str_closed);

}

static PyObject *

buffered_close(buffered *self, PyObject *args)

{

PyObject *res = NULL, *exc = NULL, *val, *tb;

int r;

CHECK_INITIALIZED(self)

if (!ENTER_BUFFERED(self))

return NULL;

r = buffered_closed(self);

if (r < 0)

goto end;

if (r > 0) {

res = Py_None;

Py_INCREF(res);

goto end;

}

if (self->finalizing) {

PyObject *r = buffered_dealloc_warn(self, (PyObject *) self);

if (r)

Py_DECREF(r);

else

PyErr_Clear();

}

/* flush() will most probably re-take the lock, so drop it first */

LEAVE_BUFFERED(self)

res = PyObject_CallMethodObjArgs((PyObject *)self, _PyIO_str_flush, NULL);

if (!ENTER_BUFFERED(self))

return NULL;

if (res == NULL)

PyErr_Fetch(&exc, &val, &tb);

else

Py_DECREF(res);

res = PyObject_CallMethodObjArgs(self->raw, _PyIO_str_close, NULL);

if (self->buffer) {

PyMem_Free(self->buffer);

self->buffer = NULL;

}

if (exc != NULL) {

_PyErr_ChainExceptions(exc, val, tb);

Py_CLEAR(res);

}

end:

LEAVE_BUFFERED(self)

return res;

}

/* detach */

static PyObject *

buffered_detach(buffered *self, PyObject *Py_UNUSED(ignored))

{

PyObject *raw, *res;

CHECK_INITIALIZED(self)

res = PyObject_CallMethodObjArgs((PyObject *)self, _PyIO_str_flush, NULL);

if (res == NULL)

return NULL;

Py_DECREF(res);

raw = self->raw;

self->raw = NULL;

self->detached = 1;

self->ok = 0;

return raw;

}

/* Inquiries */

static PyObject *

buffered_seekable(buffered *self, PyObject *Py_UNUSED(ignored))

{

CHECK_INITIALIZED(self)

return PyObject_CallMethodObjArgs(self->raw, _PyIO_str_seekable, NULL);

}

static PyObject *

buffered_readable(buffered *self, PyObject *Py_UNUSED(ignored))

{

CHECK_INITIALIZED(self)

return PyObject_CallMethodObjArgs(self->raw, _PyIO_str_readable, NULL);

}

static PyObject *

buffered_writable(buffered *self, PyObject *Py_UNUSED(ignored))

{

CHECK_INITIALIZED(self)

return PyObject_CallMethodObjArgs(self->raw, _PyIO_str_writable, NULL);

}

static PyObject *

buffered_name_get(buffered *self, void *context)

{

CHECK_INITIALIZED(self)

return _PyObject_GetAttrId(self->raw, &PyId_name);

}

static PyObject *

buffered_mode_get(buffered *self, void *context)

{

CHECK_INITIALIZED(self)

return _PyObject_GetAttrId(self->raw, &PyId_mode);

}

/* Lower-level APIs */

static PyObject *

buffered_fileno(buffered *self, PyObject *Py_UNUSED(ignored))

{

CHECK_INITIALIZED(self)

return PyObject_CallMethodObjArgs(self->raw, _PyIO_str_fileno, NULL);

}

static PyObject *

buffered_isatty(buffered *self, PyObject *Py_UNUSED(ignored))

{

CHECK_INITIALIZED(self)

return PyObject_CallMethodObjArgs(self->raw, _PyIO_str_isatty, NULL);

}

/* Serialization */

static PyObject *

buffered_getstate(buffered *self, PyObject *Py_UNUSED(ignored))

{

PyErr_Format(PyExc_TypeError,

"cannot serialize '%s' object", Py_TYPE(self)->tp_name);

return NULL;

}

/* Forward decls */

static PyObject *

_bufferedwriter_flush_unlocked(buffered *);

static Py_ssize_t

_bufferedreader_fill_buffer(buffered *self);

static void

_bufferedreader_reset_buf(buffered *self);

static void

_bufferedwriter_reset_buf(buffered *self);

static PyObject *

_bufferedreader_peek_unlocked(buffered *self);

static PyObject *

_bufferedreader_read_all(buffered *self);

static PyObject *

_bufferedreader_read_fast(buffered *self, Py_ssize_t);

static PyObject *

_bufferedreader_read_generic(buffered *self, Py_ssize_t);

static Py_ssize_t

_bufferedreader_raw_read(buffered *self, char *start, Py_ssize_t len);

* Helpers

/* Sets the current error to BlockingIOError */

static void

_set_BlockingIOError(const char *msg, Py_ssize_t written)

{

PyObject *err;

PyErr_Clear();

err = PyObject_CallFunction(PyExc_BlockingIOError, "isn",

errno, msg, written);

if (err)

PyErr_SetObject(PyExc_BlockingIOError, err);

Py_XDECREF(err);

}

/* Returns the address of the `written` member if a BlockingIOError was

raised, NULL otherwise. The error is always re-raised. */

static Py_ssize_t *

_buffered_check_blocking_error(void)

{

PyObject *t, *v, *tb;

PyOSErrorObject *err;

PyErr_Fetch(&t, &v, &tb);

if (v == NULL || !PyErr_GivenExceptionMatches(v, PyExc_BlockingIOError)) {

PyErr_Restore(t, v, tb);

return NULL;

}

err = (PyOSErrorObject *) v;

/* TODO: sanity check (err->written >= 0) */

PyErr_Restore(t, v, tb);

return &err->written;

}

static Py_off_t

_buffered_raw_tell(buffered *self)

{

Py_off_t n;

PyObject *res;

res = PyObject_CallMethodObjArgs(self->raw, _PyIO_str_tell, NULL);

if (res == NULL)

return -1;

n = PyNumber_AsOff_t(res, PyExc_ValueError);

Py_DECREF(res);

if (n < 0) {

if (!PyErr_Occurred())

PyErr_Format(PyExc_OSError,

"Raw stream returned invalid position %" PY_PRIdOFF,

(PY_OFF_T_COMPAT)n);

return -1;

}

self->abs_pos = n;

return n;

}

static Py_off_t

_buffered_raw_seek(buffered *self, Py_off_t target, int whence)

{

PyObject *res, *posobj, *whenceobj;

Py_off_t n;

posobj = PyLong_FromOff_t(target);

if (posobj == NULL)

return -1;

whenceobj = PyLong_FromLong(whence);

if (whenceobj == NULL) {

Py_DECREF(posobj);

return -1;

}

res = PyObject_CallMethodObjArgs(self->raw, _PyIO_str_seek,

posobj, whenceobj, NULL);

Py_DECREF(posobj);

Py_DECREF(whenceobj);

if (res == NULL)

return -1;

n = PyNumber_AsOff_t(res, PyExc_ValueError);

Py_DECREF(res);

if (n < 0) {

if (!PyErr_Occurred())

PyErr_Format(PyExc_OSError,

"Raw stream returned invalid position %" PY_PRIdOFF,

(PY_OFF_T_COMPAT)n);

return -1;

}

self->abs_pos = n;

return n;

}

static int

_buffered_init(buffered *self)

{

Py_ssize_t n;

if (self->buffer_size <= 0) {

PyErr_SetString(PyExc_ValueError,

"buffer size must be strictly positive");

return -1;

}

if (self->buffer)

PyMem_Free(self->buffer);

self->buffer = PyMem_Malloc(self->buffer_size);

if (self->buffer == NULL) {

PyErr_NoMemory();

return -1;

}

if (self->lock)

PyThread_free_lock(self->lock);

self->lock = PyThread_allocate_lock();

if (self->lock == NULL) {

PyErr_SetString(PyExc_RuntimeError, "can't allocate read lock");

return -1;

}

self->owner = 0;

/* Find out whether buffer_size is a power of 2 */

/* XXX is this optimization useful? */

for (n = self->buffer_size - 1; n & 1; n >>= 1)

;

if (n == 0)

self->buffer_mask = self->buffer_size - 1;

else

self->buffer_mask = 0;

if (_buffered_raw_tell(self) == -1)

PyErr_Clear();

return 0;

}

/* Return 1 if an OSError with errno == EINTR is set (and then

clears the error indicator), 0 otherwise.

Should only be called when PyErr_Occurred() is true.

int

_PyIO_trap_eintr(void)

{

static PyObject *eintr_int = NULL;

PyObject *typ, *val, *tb;

PyOSErrorObject *env_err;

if (eintr_int == NULL) {

eintr_int = PyLong_FromLong(EINTR);

assert(eintr_int != NULL);

}

if (!PyErr_ExceptionMatches(PyExc_OSError))

return 0;

PyErr_Fetch(&typ, &val, &tb);

PyErr_NormalizeException(&typ, &val, &tb);

env_err = (PyOSErrorObject *) val;

assert(env_err != NULL);

if (env_err->myerrno != NULL &&

PyObject_RichCompareBool(env_err->myerrno, eintr_int, Py_EQ) > 0) {

Py_DECREF(typ);

Py_DECREF(val);

Py_XDECREF(tb);

return 1;

}

/* This silences any error set by PyObject_RichCompareBool() */

PyErr_Restore(typ, val, tb);

return 0;

}

* Shared methods and wrappers

static PyObject *

buffered_flush_and_rewind_unlocked(buffered *self)

{

PyObject *res;

res = _bufferedwriter_flush_unlocked(self);

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;

CHECK_INITIALIZED(self)

CHECK_CLOSED(self, "flush of closed file")

if (!ENTER_BUFFERED(self))

return NULL;

res = buffered_flush_and_rewind_unlocked(self);

LEAVE_BUFFERED(self)

return res;

}

/*[clinic input]

_io._Buffered.peek

size: Py_ssize_t = 0

[clinic start generated code]*/

static PyObject *

_io__Buffered_peek_impl(buffered *self, Py_ssize_t size)

/*[clinic end generated code: output=ba7a097ca230102b input=37ffb97d06ff4adb]*/

{

PyObject *res = NULL;

CHECK_INITIALIZED(self)

CHECK_CLOSED(self, "peek of closed file")

if (!ENTER_BUFFERED(self))

return NULL;

if (self->writable) {

res = buffered_flush_and_rewind_unlocked(self);

if (res == NULL)

goto end;

Py_CLEAR(res);

}

res = _bufferedreader_peek_unlocked(self);

end:

LEAVE_BUFFERED(self)

return res;

}

/*[clinic input]

_io._Buffered.read

size as n: Py_ssize_t(accept={int, NoneType}) = -1

[clinic start generated code]*/

static PyObject *

_io__Buffered_read_impl(buffered *self, Py_ssize_t n)

/*[clinic end generated code: output=f41c78bb15b9bbe9 input=7df81e82e08a68a2]*/

{

PyObject *res;

CHECK_INITIALIZED(self)

if (n < -1) {

PyErr_SetString(PyExc_ValueError,

"read length must be non-negative or -1");

return NULL;

}

CHECK_CLOSED(self, "read of closed file")

if (n == -1) {

/* The number of bytes is unspecified, read until the end of stream */

if (!ENTER_BUFFERED(self))

return NULL;

res = _bufferedreader_read_all(self);

}

else {

res = _bufferedreader_read_fast(self, n);

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;

}

/*[clinic input]

_io._Buffered.read1

size as n: Py_ssize_t = -1

[clinic start generated code]*/

static PyObject *

_io__Buffered_read1_impl(buffered *self, Py_ssize_t n)

/*[clinic end generated code: output=bcc4fb4e54d103a3 input=7d22de9630b61774]*/

{

Py_ssize_t have, r;

PyObject *res = NULL;

CHECK_INITIALIZED(self)

if (n < 0) {

n = self->buffer_size;

}

CHECK_CLOSED(self, "read of closed file")

if (n == 0)

return PyBytes_FromStringAndSize(NULL, 0);

/* Return up to n bytes. If at least one byte is buffered, we

only return buffered bytes. Otherwise, we do one raw read. */

have = Py_SAFE_DOWNCAST(READAHEAD(self), Py_off_t, Py_ssize_t);

if (have > 0) {

n = Py_MIN(have, n);

res = _bufferedreader_read_fast(self, n);

assert(res != Py_None);

return res;

}

res = PyBytes_FromStringAndSize(NULL, n);

if (res == NULL)

return NULL;

if (!ENTER_BUFFERED(self)) {

Py_DECREF(res);

return NULL;

}

_bufferedreader_reset_buf(self);

r = _bufferedreader_raw_read(self, PyBytes_AS_STRING(res), n);

LEAVE_BUFFERED(self)

if (r == -1) {

Py_DECREF(res);

return NULL;

}

if (r == -2)

r = 0;

if (n > r)

_PyBytes_Resize(&res, r);

return res;

}

static PyObject *

_buffered_readinto_generic(buffered *self, Py_buffer *buffer, char readinto1)

{

Py_ssize_t n, written = 0, remaining;

PyObject *res = NULL;

CHECK_INITIALIZED(self)

n = Py_SAFE_DOWNCAST(READAHEAD(self), Py_off_t, Py_ssize_t);

if (n > 0) {

if (n >= buffer->len) {

memcpy(buffer->buf, self->buffer + self->pos, buffer->len);

self->pos += buffer->len;

return PyLong_FromSsize_t(buffer->len);

}

memcpy(buffer->buf, self->buffer + self->pos, n);

self->pos += n;

written = n;

}

if (!ENTER_BUFFERED(self))

return NULL;

if (self->writable) {

res = buffered_flush_and_rewind_unlocked(self);

if (res == NULL)

goto end;

Py_CLEAR(res);

}

_bufferedreader_reset_buf(self);

View remainder of file in raw view

cpython/Modules/_io/bufferedio.c at pythoncapi · pythoncapi/cpython · GitHub

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