cpython/Modules/_io/stringio.c at 3.15 · python/cpython · GitHub

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#include "Python.h"

#include <stddef.h> // offsetof()

#include "pycore_object.h"

#include "pycore_weakref.h" // FT_CLEAR_WEAKREFS()

#include "_iomodule.h"

/* Implementation note: the buffer is always at least one character longer

than the enclosed string, for proper functioning of _PyIO_find_line_ending.

#define STATE_REALIZED 1

#define STATE_ACCUMULATING 2

/*[clinic input]

module _io

class _io.StringIO "stringio *" "clinic_state()->PyStringIO_Type"

[clinic start generated code]*/

/*[clinic end generated code: output=da39a3ee5e6b4b0d input=2693eada0658d470]*/

typedef struct {

PyObject_HEAD

Py_UCS4 *buf;

Py_ssize_t pos;

Py_ssize_t string_size;

size_t buf_size;

/* The stringio object can be in two states: accumulating or realized.

In accumulating state, the internal buffer contains nothing and

the contents are given by the embedded _PyUnicodeWriter structure.

In realized state, the internal buffer is meaningful and the

_PyUnicodeWriter is destroyed.

int state;

PyUnicodeWriter *writer;

char ok; /* initialized? */

char closed;

char readuniversal;

char readtranslate;

PyObject *decoder;

PyObject *readnl;

PyObject *writenl;

PyObject *dict;

PyObject *weakreflist;

_PyIO_State *module_state;

} stringio;

#define stringio_CAST(op) ((stringio *)(op))

#define clinic_state() (find_io_state_by_def(Py_TYPE(self)))

#include "clinic/stringio.c.h"

#undef clinic_state

static int _io_StringIO___init__(PyObject *self, PyObject *args, PyObject *kwargs);

#define CHECK_INITIALIZED(self) \

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

PyErr_SetString(PyExc_ValueError, \

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

return NULL; \

}

#define CHECK_CLOSED(self) \

if (self->closed) { \

PyErr_SetString(PyExc_ValueError, \

"I/O operation on closed file"); \

return NULL; \

}

#define ENSURE_REALIZED(self) \

if (realize(self) < 0) { \

return NULL; \

}

/* Internal routine for changing the size, in terms of characters, of the

buffer of StringIO objects. The caller should ensure that the 'size'

argument is non-negative. Returns 0 on success, -1 otherwise. */

static int

resize_buffer(stringio *self, size_t size)

{

/* Here, unsigned types are used to avoid dealing with signed integer

overflow, which is undefined in C. */

size_t alloc = self->buf_size;

Py_UCS4 *new_buf = NULL;

assert(self->buf != NULL);

/* Reserve one more char for line ending detection. */

size = size + 1;

/* For simplicity, stay in the range of the signed type. Anyway, Python

doesn't allow strings to be longer than this. */

if (size > PY_SSIZE_T_MAX)

goto overflow;

if (size < alloc / 2) {

/* Major downsize; resize down to exact size. */

alloc = size + 1;

}

else if (size < alloc) {

/* Within allocated size; quick exit */

return 0;

}

else if (size <= alloc * 1.125) {

/* Moderate upsize; overallocate similar to list_resize() */

alloc = size + (size >> 3) + (size < 9 ? 3 : 6);

}

else {

/* Major upsize; resize up to exact size */

alloc = size + 1;

}

if (alloc > SIZE_MAX / sizeof(Py_UCS4))

goto overflow;

new_buf = (Py_UCS4 *)PyMem_Realloc(self->buf, alloc * sizeof(Py_UCS4));

if (new_buf == NULL) {

PyErr_NoMemory();

return -1;

}

self->buf_size = alloc;

self->buf = new_buf;

return 0;

overflow:

PyErr_SetString(PyExc_OverflowError,

"new buffer size too large");

return -1;

}

static PyObject *

make_intermediate(stringio *self)

{

PyObject *intermediate = PyUnicodeWriter_Finish(self->writer);

self->writer = NULL;

self->state = STATE_REALIZED;

if (intermediate == NULL)

return NULL;

self->writer = PyUnicodeWriter_Create(0);

if (self->writer == NULL) {

Py_DECREF(intermediate);

return NULL;

}

if (PyUnicodeWriter_WriteStr(self->writer, intermediate)) {

Py_DECREF(intermediate);

return NULL;

}

self->state = STATE_ACCUMULATING;

return intermediate;

}

static int

realize(stringio *self)

{

Py_ssize_t len;

PyObject *intermediate;

if (self->state == STATE_REALIZED)

return 0;

assert(self->state == STATE_ACCUMULATING);

self->state = STATE_REALIZED;

intermediate = PyUnicodeWriter_Finish(self->writer);

self->writer = NULL;

if (intermediate == NULL)

return -1;

/* Append the intermediate string to the internal buffer.

The length should be equal to the current cursor position.

len = PyUnicode_GET_LENGTH(intermediate);

if (resize_buffer(self, len) < 0) {

Py_DECREF(intermediate);

return -1;

}

if (!PyUnicode_AsUCS4(intermediate, self->buf, len, 0)) {

Py_DECREF(intermediate);

return -1;

}

Py_DECREF(intermediate);

return 0;

}

/* Internal routine for writing a whole PyUnicode object to the buffer of a

StringIO object. Returns 0 on success, or -1 on error. */

static Py_ssize_t

write_str(stringio *self, PyObject *obj)

{

Py_ssize_t len;

PyObject *decoded = NULL;

assert(self->buf != NULL);

assert(self->pos >= 0);

if (self->decoder != NULL) {

decoded = _PyIncrementalNewlineDecoder_decode(

self->decoder, obj, 1 /* always final */);

}

else {

decoded = Py_NewRef(obj);

}

if (self->writenl) {

PyObject *translated = PyUnicode_Replace(

decoded, _Py_LATIN1_CHR('\n'), self->writenl, -1);

Py_SETREF(decoded, translated);

}

if (decoded == NULL)

return -1;

assert(PyUnicode_Check(decoded));

len = PyUnicode_GET_LENGTH(decoded);

assert(len >= 0);

/* This overflow check is not strictly necessary. However, it avoids us to

deal with funky things like comparing an unsigned and a signed

integer. */

if (self->pos > PY_SSIZE_T_MAX - len) {

PyErr_SetString(PyExc_OverflowError,

"new position too large");

goto fail;

}

if (self->state == STATE_ACCUMULATING) {

if (self->string_size == self->pos) {

// gh-149046: Avoid PyUnicodeWriter_WriteStr() which calls str(obj)

// on str subclasses

if (_PyUnicodeWriter_WriteStr((_PyUnicodeWriter*)self->writer, decoded))

goto fail;

goto success;

}

if (realize(self))

goto fail;

}

if (self->pos + len > self->string_size) {

if (resize_buffer(self, self->pos + len) < 0)

goto fail;

}

if (self->pos > self->string_size) {

/* In case of overseek, pad with null bytes the buffer region between

the end of stream and the current position.

0 lo string_size hi

| |<---used--->|<----------available----------->|

| | <--to pad-->|<---to write---> |

0 buf position

memset(self->buf + self->string_size, '\0',

(self->pos - self->string_size) * sizeof(Py_UCS4));

}

/* Copy the data to the internal buffer, overwriting some of the

existing data if self->pos < self->string_size. */

if (!PyUnicode_AsUCS4(decoded,

self->buf + self->pos,

self->buf_size - self->pos,

0))

goto fail;

success:

/* Set the new length of the internal string if it has changed. */

self->pos += len;

if (self->string_size < self->pos)

self->string_size = self->pos;

Py_DECREF(decoded);

return 0;

fail:

Py_XDECREF(decoded);

return -1;

}

/*[clinic input]

@critical_section

_io.StringIO.getvalue

Retrieve the entire contents of the object.

[clinic start generated code]*/

static PyObject *

_io_StringIO_getvalue_impl(stringio *self)

/*[clinic end generated code: output=27b6a7bfeaebce01 input=fb5dee06b8d467f3]*/

{

CHECK_INITIALIZED(self);

CHECK_CLOSED(self);

if (self->state == STATE_ACCUMULATING)

return make_intermediate(self);

return PyUnicode_FromKindAndData(PyUnicode_4BYTE_KIND, self->buf,

self->string_size);

}

/*[clinic input]

@critical_section

_io.StringIO.tell

Tell the current file position.

[clinic start generated code]*/

static PyObject *

_io_StringIO_tell_impl(stringio *self)

/*[clinic end generated code: output=2e87ac67b116c77b input=98a08f3e2dae3550]*/

{

CHECK_INITIALIZED(self);

CHECK_CLOSED(self);

return PyLong_FromSsize_t(self->pos);

}

/*[clinic input]

@critical_section

_io.StringIO.read

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

Read at most size characters, returned as a string.

If the argument is negative or omitted, read until EOF

is reached. Return an empty string at EOF.

[clinic start generated code]*/

static PyObject *

_io_StringIO_read_impl(stringio *self, Py_ssize_t size)

/*[clinic end generated code: output=ae8cf6002f71626c input=9fbef45d8aece8e7]*/

{

Py_ssize_t n;

Py_UCS4 *output;

CHECK_INITIALIZED(self);

CHECK_CLOSED(self);

/* adjust invalid sizes */

n = self->string_size - self->pos;

if (size < 0 || size > n) {

size = n;

if (size < 0)

size = 0;

}

/* Optimization for seek(0); read() */

if (self->state == STATE_ACCUMULATING && self->pos == 0 && size == n) {

PyObject *result = make_intermediate(self);

self->pos = self->string_size;

return result;

}

ENSURE_REALIZED(self);

output = self->buf + self->pos;

self->pos += size;

return PyUnicode_FromKindAndData(PyUnicode_4BYTE_KIND, output, size);

}

/* Internal helper, used by stringio_readline and stringio_iternext */

static PyObject *

_stringio_readline(stringio *self, Py_ssize_t limit)

{

Py_UCS4 *start, *end, old_char;

Py_ssize_t len, consumed;

/* In case of overseek, return the empty string */

if (self->pos >= self->string_size)

return Py_GetConstant(Py_CONSTANT_EMPTY_STR);

start = self->buf + self->pos;

if (limit < 0 || limit > self->string_size - self->pos)

limit = self->string_size - self->pos;

end = start + limit;

old_char = *end;

*end = '\0';

len = _PyIO_find_line_ending(

self->readtranslate, self->readuniversal, self->readnl,

PyUnicode_4BYTE_KIND, (char*)start, (char*)end, &consumed);

*end = old_char;

/* If we haven't found any line ending, we just return everything

(`consumed` is ignored). */

if (len < 0)

len = limit;

self->pos += len;

return PyUnicode_FromKindAndData(PyUnicode_4BYTE_KIND, start, len);

}

/*[clinic input]

@critical_section

_io.StringIO.readline

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

Read until newline or EOF.

Returns an empty string if EOF is hit immediately.

[clinic start generated code]*/

static PyObject *

_io_StringIO_readline_impl(stringio *self, Py_ssize_t size)

/*[clinic end generated code: output=cabd6452f1b7e85d input=4d14b8495dea1d98]*/

{

CHECK_INITIALIZED(self);

CHECK_CLOSED(self);

ENSURE_REALIZED(self);

return _stringio_readline(self, size);

}

static PyObject *

stringio_iternext(PyObject *op)

{

PyObject *line;

stringio *self = stringio_CAST(op);

CHECK_INITIALIZED(self);

CHECK_CLOSED(self);

ENSURE_REALIZED(self);

if (Py_IS_TYPE(self, self->module_state->PyStringIO_Type)) {

/* Skip method call overhead for speed */

line = _stringio_readline(self, -1);

}

else {

/* XXX is subclassing StringIO really supported? */

line = PyObject_CallMethodNoArgs(op, &_Py_ID(readline));

if (line && !PyUnicode_Check(line)) {

PyErr_Format(PyExc_OSError,

"readline() should have returned a str object, "

"not '%.200s'", Py_TYPE(line)->tp_name);

Py_DECREF(line);

return NULL;

}

if (line == NULL)

return NULL;

if (PyUnicode_GET_LENGTH(line) == 0) {

/* Reached EOF */

Py_DECREF(line);

return NULL;

}

return line;

}

/*[clinic input]

@critical_section

_io.StringIO.truncate

pos: object = None

Truncate size to pos.

The pos argument defaults to the current file position, as

returned by tell(). The current file position is unchanged.

Returns the new absolute position.

[clinic start generated code]*/

static PyObject *

_io_StringIO_truncate_impl(stringio *self, PyObject *pos)

/*[clinic end generated code: output=c76c43b5ecfaf4e2 input=d59fd2ee49757ae6]*/

{

CHECK_INITIALIZED(self);

CHECK_CLOSED(self);

Py_ssize_t size;

if (pos == Py_None) {

size = self->pos;

}

else {

size = PyLong_AsLong(pos);

if (size == -1 && PyErr_Occurred()) {

return NULL;

}

if (size < 0) {

PyErr_Format(PyExc_ValueError,

"negative pos value %zd", size);

return NULL;

}

if (size < self->string_size) {

ENSURE_REALIZED(self);

if (resize_buffer(self, size) < 0)

return NULL;

self->string_size = size;

}

return PyLong_FromSsize_t(size);

}

/*[clinic input]

@critical_section

_io.StringIO.seek

pos: Py_ssize_t

whence: int = 0

Change stream position.

Seek to character offset pos relative to position indicated by

whence:

0 Start of stream (the default). pos should be >= 0;

1 Current position - pos must be 0;

2 End of stream - pos must be 0.

Returns the new absolute position.

[clinic start generated code]*/

static PyObject *

_io_StringIO_seek_impl(stringio *self, Py_ssize_t pos, int whence)

/*[clinic end generated code: output=e9e0ac9a8ae71c25 input=ffef24668fd71a5d]*/

{

CHECK_INITIALIZED(self);

CHECK_CLOSED(self);

if (whence != 0 && whence != 1 && whence != 2) {

PyErr_Format(PyExc_ValueError,

"Invalid whence (%i, should be 0, 1 or 2)", whence);

return NULL;

}

else if (pos < 0 && whence == 0) {

PyErr_Format(PyExc_ValueError,

"Negative seek position %zd", pos);

return NULL;

}

else if (whence != 0 && pos != 0) {

PyErr_SetString(PyExc_OSError,

"Can't do nonzero cur-relative seeks");

return NULL;

}

/* whence = 0: offset relative to beginning of the string.

whence = 1: no change to current position.

whence = 2: change position to end of file. */

if (whence == 1) {

pos = self->pos;

}

else if (whence == 2) {

pos = self->string_size;

}

self->pos = pos;

return PyLong_FromSsize_t(self->pos);

}

/*[clinic input]

@critical_section

_io.StringIO.write

s as obj: object

Write string to file.

Returns the number of characters written, which is always equal to

the length of the string.

[clinic start generated code]*/

static PyObject *

_io_StringIO_write_impl(stringio *self, PyObject *obj)

/*[clinic end generated code: output=d53b1d841d7db288 input=1561272c0da4651f]*/

{

Py_ssize_t size;

CHECK_INITIALIZED(self);

if (!PyUnicode_Check(obj)) {

PyErr_Format(PyExc_TypeError, "string argument expected, got '%s'",

Py_TYPE(obj)->tp_name);

return NULL;

}

CHECK_CLOSED(self);

size = PyUnicode_GET_LENGTH(obj);

if (size > 0 && write_str(self, obj) < 0)

return NULL;

return PyLong_FromSsize_t(size);

}

/*[clinic input]

@critical_section

_io.StringIO.close

Close the IO object.

Attempting any further operation after the object is closed

will raise a ValueError.

This method has no effect if the file is already closed.

[clinic start generated code]*/

static PyObject *

_io_StringIO_close_impl(stringio *self)

/*[clinic end generated code: output=04399355cbe518f1 input=305d19aa29cc40b9]*/

{

self->closed = 1;

/* Free up some memory */

if (resize_buffer(self, 0) < 0)

return NULL;

PyUnicodeWriter_Discard(self->writer);

self->writer = NULL;

Py_CLEAR(self->readnl);

Py_CLEAR(self->writenl);

Py_CLEAR(self->decoder);

Py_RETURN_NONE;

}

static int

stringio_traverse(PyObject *op, visitproc visit, void *arg)

{

stringio *self = stringio_CAST(op);

Py_VISIT(Py_TYPE(self));

Py_VISIT(self->readnl);

Py_VISIT(self->writenl);

Py_VISIT(self->decoder);

Py_VISIT(self->dict);

return 0;

}

static int

stringio_clear(PyObject *op)

{

stringio *self = stringio_CAST(op);

Py_CLEAR(self->readnl);

Py_CLEAR(self->writenl);

Py_CLEAR(self->decoder);

Py_CLEAR(self->dict);

return 0;

}

static void

stringio_dealloc(PyObject *op)

{

stringio *self = stringio_CAST(op);

PyTypeObject *tp = Py_TYPE(self);

_PyObject_GC_UNTRACK(self);

self->ok = 0;

if (self->buf) {

PyMem_Free(self->buf);

self->buf = NULL;

}

PyUnicodeWriter_Discard(self->writer);

(void)stringio_clear(op);

FT_CLEAR_WEAKREFS(op, self->weakreflist);

tp->tp_free(self);

Py_DECREF(tp);

}

static PyObject *

stringio_new(PyTypeObject *type, PyObject *args, PyObject *kwds)

{

stringio *self;

assert(type != NULL && type->tp_alloc != NULL);

self = (stringio *)type->tp_alloc(type, 0);

if (self == NULL)

return NULL;

/* tp_alloc initializes all the fields to zero. So we don't have to

initialize them here. */

self->buf = (Py_UCS4 *)PyMem_Malloc(0);

if (self->buf == NULL) {

Py_DECREF(self);

return PyErr_NoMemory();

}

return (PyObject *)self;

}

/*[clinic input]

_io.StringIO.__init__

initial_value as value: object(c_default="NULL") = ''

newline as newline_obj: object(c_default="NULL") = '\n'

Text I/O implementation using an in-memory buffer.

The initial_value argument sets the value of object. The newline

argument is like the one of TextIOWrapper's constructor.

[clinic start generated code]*/

static int

_io_StringIO___init___impl(stringio *self, PyObject *value,

PyObject *newline_obj)

/*[clinic end generated code: output=a421ea023b22ef4e input=cee2d9181b2577a3]*/

{

const char *newline = "\n";

Py_ssize_t value_len;

/* Parse the newline argument. We only want to allow unicode objects or

None. */

if (newline_obj == Py_None) {

newline = NULL;

}

else if (newline_obj) {

if (!PyUnicode_Check(newline_obj)) {

PyErr_Format(PyExc_TypeError,

"newline must be str or None, not %.200s",

Py_TYPE(newline_obj)->tp_name);

return -1;

}

newline = PyUnicode_AsUTF8(newline_obj);

if (newline == NULL)

return -1;

}

if (newline && newline[0] != '\0'

&& !(newline[0] == '\n' && newline[1] == '\0')

&& !(newline[0] == '\r' && newline[1] == '\0')

&& !(newline[0] == '\r' && newline[1] == '\n' && newline[2] == '\0')) {

PyErr_Format(PyExc_ValueError,

"illegal newline value: %R", newline_obj);

return -1;

}

if (value && value != Py_None && !PyUnicode_Check(value)) {

PyErr_Format(PyExc_TypeError,

"initial_value must be str or None, not %.200s",

Py_TYPE(value)->tp_name);

return -1;

}

self->ok = 0;

PyUnicodeWriter_Discard(self->writer);

self->writer = NULL;

Py_CLEAR(self->readnl);

Py_CLEAR(self->writenl);

Py_CLEAR(self->decoder);

assert((newline != NULL && newline_obj != Py_None) ||

(newline == NULL && newline_obj == Py_None));

if (newline) {

self->readnl = PyUnicode_FromString(newline);

if (self->readnl == NULL)

return -1;

}

self->readuniversal = (newline == NULL || newline[0] == '\0');

self->readtranslate = (newline == NULL);

/* If newline == "", we don't translate anything.

If newline == "\n" or newline == None, we translate to "\n", which is

a no-op.

(for newline == None, TextIOWrapper translates to os.linesep, but it

is pointless for StringIO)

if (newline != NULL && newline[0] == '\r') {

self->writenl = Py_NewRef(self->readnl);

}

_PyIO_State *module_state = find_io_state_by_def(Py_TYPE(self));

if (self->readuniversal) {

self->decoder = PyObject_CallFunctionObjArgs(

(PyObject *)module_state->PyIncrementalNewlineDecoder_Type,

Py_None, self->readtranslate ? Py_True : Py_False, NULL);

if (self->decoder == NULL)

return -1;

}

/* Now everything is set up, resize buffer to size of initial value,

and copy it */

self->string_size = 0;

if (value && value != Py_None)

value_len = PyUnicode_GetLength(value);

else

value_len = 0;

if (value_len > 0) {

/* This is a heuristic, for newline translation might change

the string length. */

if (resize_buffer(self, 0) < 0)

return -1;

self->state = STATE_REALIZED;

self->pos = 0;

if (write_str(self, value) < 0)

return -1;

}

else {

/* Empty stringio object, we can start by accumulating */

if (resize_buffer(self, 0) < 0)

return -1;

self->writer = PyUnicodeWriter_Create(0);

if (self->writer == NULL) {

return -1;

}

self->state = STATE_ACCUMULATING;

}

self->pos = 0;

self->module_state = module_state;

self->closed = 0;

self->ok = 1;

return 0;

}

/* Properties and pseudo-properties */

/*[clinic input]

@critical_section

_io.StringIO.readable

Returns True if the IO object can be read.

[clinic start generated code]*/

static PyObject *

_io_StringIO_readable_impl(stringio *self)

/*[clinic end generated code: output=b19d44dd8b1ceb99 input=6cd2ffd65a8e8763]*/

{

CHECK_INITIALIZED(self);

CHECK_CLOSED(self);

Py_RETURN_TRUE;

}

/*[clinic input]

@critical_section

_io.StringIO.writable

Returns True if the IO object can be written.

[clinic start generated code]*/

static PyObject *

_io_StringIO_writable_impl(stringio *self)

/*[clinic end generated code: output=13e4dd77187074ca input=1b3c63dbaa761c69]*/

{

CHECK_INITIALIZED(self);

CHECK_CLOSED(self);

Py_RETURN_TRUE;

}

/*[clinic input]

@critical_section

_io.StringIO.seekable

Returns True if the IO object can be seeked.

[clinic start generated code]*/

static PyObject *

_io_StringIO_seekable_impl(stringio *self)

/*[clinic end generated code: output=4d20b4641c756879 input=a820fad2cf085fc3]*/

{

CHECK_INITIALIZED(self);

CHECK_CLOSED(self);

Py_RETURN_TRUE;

}

/* Pickling support.

The implementation of __getstate__ is similar to the one for BytesIO,

except that we also save the newline parameter. For __setstate__ and unlike

BytesIO, we call __init__ to restore the object's state. Doing so allows us

to avoid decoding the complex newline state while keeping the object

representation compact.

See comment in bytesio.c regarding why only pickle protocols and onward are

supported.

/*[clinic input]

@critical_section

_io.StringIO.__getstate__

[clinic start generated code]*/

static PyObject *

_io_StringIO___getstate___impl(stringio *self)

/*[clinic end generated code: output=780be4a996410199 input=76f27255ef83bb92]*/

{

PyObject *initvalue = _io_StringIO_getvalue_impl(self);

PyObject *dict;

PyObject *state;

if (initvalue == NULL)

return NULL;

if (self->dict == NULL) {

dict = Py_NewRef(Py_None);

}

else {

dict = PyDict_Copy(self->dict);

if (dict == NULL) {

Py_DECREF(initvalue);

return NULL;

}

state = Py_BuildValue("(OOnN)", initvalue,

self->readnl ? self->readnl : Py_None,

self->pos, dict);

Py_DECREF(initvalue);

return state;

}

/*[clinic input]

@critical_section

_io.StringIO.__setstate__

state: object

[clinic start generated code]*/

static PyObject *

_io_StringIO___setstate___impl(stringio *self, PyObject *state)

/*[clinic end generated code: output=cb3962bc6d5c5609 input=8a27784b11b82e47]*/

{

PyObject *initarg;

PyObject *position_obj;

PyObject *dict;

Py_ssize_t pos;

assert(state != NULL);

CHECK_CLOSED(self);

/* We allow the state tuple to be longer than 4, because we may need

someday to extend the object's state without breaking

backward-compatibility. */

if (!PyTuple_Check(state) || PyTuple_GET_SIZE(state) < 4) {

PyErr_Format(PyExc_TypeError,

"%.200s.__setstate__ argument should be 4-tuple, got %.200s",

Py_TYPE(self)->tp_name, Py_TYPE(state)->tp_name);

return NULL;

}

/* Initialize the object's state. */

initarg = PyTuple_GetSlice(state, 0, 2);

if (initarg == NULL)

return NULL;

if (_io_StringIO___init__((PyObject *)self, initarg, NULL) < 0) {

Py_DECREF(initarg);

return NULL;

}

Py_DECREF(initarg);

/* Restore the buffer state. Even if __init__ did initialize the buffer,

we have to initialize it again since __init__ may translate the

newlines in the initial_value string. We clearly do not want that

because the string value in the state tuple has already been translated

once by __init__. So we do not take any chance and replace object's

buffer completely. */

{

PyObject *item = PyTuple_GET_ITEM(state, 0);

if (PyUnicode_Check(item)) {

Py_UCS4 *buf = PyUnicode_AsUCS4Copy(item);

if (buf == NULL)

return NULL;

Py_ssize_t bufsize = PyUnicode_GET_LENGTH(item);

if (resize_buffer(self, bufsize) < 0) {

PyMem_Free(buf);

return NULL;

}

memcpy(self->buf, buf, bufsize * sizeof(Py_UCS4));

PyMem_Free(buf);

self->string_size = bufsize;

}

else {

assert(item == Py_None);

self->string_size = 0;

}

/* Set carefully the position value. Alternatively, we could use the seek

method instead of modifying self->pos directly to better protect the

object internal state against erroneous (or malicious) inputs. */

position_obj = PyTuple_GET_ITEM(state, 2);

if (!PyLong_Check(position_obj)) {

PyErr_Format(PyExc_TypeError,

"third item of state must be an integer, got %.200s",

Py_TYPE(position_obj)->tp_name);

return NULL;

}

pos = PyLong_AsSsize_t(position_obj);

if (pos == -1 && PyErr_Occurred())

return NULL;

if (pos < 0) {

PyErr_SetString(PyExc_ValueError,

"position value cannot be negative");

return NULL;

}

self->pos = pos;

/* Set the dictionary of the instance variables. */

dict = PyTuple_GET_ITEM(state, 3);

if (dict != Py_None) {

if (!PyDict_Check(dict)) {

PyErr_Format(PyExc_TypeError,

"fourth item of state should be a dict, got a %.200s",

Py_TYPE(dict)->tp_name);

return NULL;

}

if (self->dict) {

/* Alternatively, we could replace the internal dictionary

completely. However, it seems more practical to just update it. */

if (PyDict_Update(self->dict, dict) < 0)

return NULL;

}

else {

self->dict = Py_NewRef(dict);

}

Py_RETURN_NONE;

}

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cpython/Modules/_io/stringio.c at 3.15 · python/cpython · GitHub

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