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085cf0e3e4
circuitpython/py/stream.c
Jeff Epler 085cf0e3e4
make mp_stream_flush available
2023-09-22 13:52:04 -05:00

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/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2014 Damien P. George
* Copyright (c) 2014-2016 Paul Sokolovsky
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include <string.h>
#include <unistd.h>
#include "py/objstr.h"
#include "py/stream.h"
#include "py/runtime.h"
// This file defines generic Python stream read/write methods which
// dispatch to the underlying stream interface of an object.
// TODO: should be in mpconfig.h
#define DEFAULT_BUFFER_SIZE 256
STATIC mp_obj_t stream_readall(mp_obj_t self_in);
// Returns error condition in *errcode, if non-zero, return value is number of bytes written
// before error condition occurred. If *errcode == 0, returns total bytes written (which will
// be equal to input size).
mp_uint_t mp_stream_rw(mp_obj_t stream, void *buf_, mp_uint_t size, int *errcode, byte flags) {
byte *buf = buf_;
typedef mp_uint_t (*io_func_t)(mp_obj_t obj, void *buf, mp_uint_t size, int *errcode);
io_func_t io_func;
const mp_stream_p_t *stream_p = mp_get_stream(stream);
if (flags & MP_STREAM_RW_WRITE) {
io_func = (io_func_t)stream_p->write;
} else {
io_func = stream_p->read;
}
*errcode = 0;
mp_uint_t done = 0;
while (size > 0) {
mp_uint_t out_sz = io_func(stream, buf, size, errcode);
// For read, out_sz == 0 means EOF. For write, it's unspecified
// what it means, but we don't make any progress, so returning
// is still the best option.
if (out_sz == 0) {
return done;
}
if (out_sz == MP_STREAM_ERROR) {
// If we read something before getting EAGAIN, don't leak it
if (mp_is_nonblocking_error(*errcode) && done != 0) {
*errcode = 0;
}
return done;
}
if (flags & MP_STREAM_RW_ONCE) {
return out_sz;
}
buf += out_sz;
size -= out_sz;
done += out_sz;
}
return done;
}
const mp_stream_p_t *mp_get_stream_raise(mp_obj_t self_in, int flags) {
const mp_obj_type_t *type = mp_obj_get_type(self_in);
if (MP_OBJ_TYPE_HAS_SLOT(type, protocol)) {
const mp_stream_p_t *stream_p = MP_OBJ_TYPE_GET_SLOT(type, protocol);
if (!((flags & MP_STREAM_OP_READ) && stream_p->read == NULL)
&& !((flags & MP_STREAM_OP_WRITE) && stream_p->write == NULL)
&& !((flags & MP_STREAM_OP_IOCTL) && stream_p->ioctl == NULL)) {
return stream_p;
}
}
// CPython: io.UnsupportedOperation, OSError subclass
mp_raise_msg(&mp_type_OSError, MP_ERROR_TEXT("stream operation not supported"));
}
STATIC mp_obj_t stream_read_generic(size_t n_args, const mp_obj_t *args, byte flags) {
// What to do if sz < -1? Python docs don't specify this case.
// CPython does a readall, but here we silently let negatives through,
// and they will cause a MemoryError.
mp_int_t sz;
if (n_args == 1 || ((sz = mp_obj_get_int(args[1])) == -1)) {
return stream_readall(args[0]);
}
const mp_stream_p_t *stream_p = mp_get_stream(args[0]);
#if MICROPY_PY_BUILTINS_STR_UNICODE
if (stream_p->is_text) {
// We need to read sz number of unicode characters. Because we don't have any
// buffering, and because the stream API can only read bytes, we must read here
// in units of bytes and must never over read. If we want sz chars, then reading
// sz bytes will never over-read, so we follow this approach, in a loop to keep
// reading until we have exactly enough chars. This will be 1 read for text
// with ASCII-only chars, and about 2 reads for text with a couple of non-ASCII
// chars. For text with lots of non-ASCII chars, it'll be pretty inefficient
// in time and memory.
vstr_t vstr;
vstr_init(&vstr, sz);
mp_uint_t more_bytes = sz;
mp_uint_t last_buf_offset = 0;
while (more_bytes > 0) {
char *p = vstr_add_len(&vstr, more_bytes);
int error;
mp_uint_t out_sz = mp_stream_read_exactly(args[0], p, more_bytes, &error);
if (error != 0) {
vstr_cut_tail_bytes(&vstr, more_bytes);
if (mp_is_nonblocking_error(error)) {
// With non-blocking streams, we read as much as we can.
// If we read nothing, return None, just like read().
// Otherwise, return data read so far.
// TODO what if we have read only half a non-ASCII char?
if (vstr.len == 0) {
vstr_clear(&vstr);
return mp_const_none;
}
break;
}
mp_raise_OSError(error);
}
if (out_sz < more_bytes) {
// Finish reading.
// TODO what if we have read only half a non-ASCII char?
vstr_cut_tail_bytes(&vstr, more_bytes - out_sz);
if (out_sz == 0) {
break;
}
}
// count chars from bytes just read
for (mp_uint_t off = last_buf_offset;;) {
byte b = vstr.buf[off];
int n;
if (!UTF8_IS_NONASCII(b)) {
// 1-byte ASCII char
n = 1;
} else if ((b & 0xe0) == 0xc0) {
// 2-byte char
n = 2;
} else if ((b & 0xf0) == 0xe0) {
// 3-byte char
n = 3;
} else if ((b & 0xf8) == 0xf0) {
// 4-byte char
n = 4;
} else {
// TODO
n = 5;
}
if (off + n <= vstr.len) {
// got a whole char in n bytes
off += n;
sz -= 1;
last_buf_offset = off;
if (off >= vstr.len) {
more_bytes = sz;
break;
}
} else {
// didn't get a whole char, so work out how many extra bytes are needed for
// this partial char, plus bytes for additional chars that we want
more_bytes = (off + n - vstr.len) + (sz - 1);
break;
}
}
}
return mp_obj_new_str_from_vstr(&vstr);
}
#endif
vstr_t vstr;
vstr_init_len(&vstr, sz);
int error;
mp_uint_t out_sz = mp_stream_rw(args[0], vstr.buf, sz, &error, flags);
if (error != 0) {
vstr_clear(&vstr);
if (mp_is_nonblocking_error(error)) {
// https://docs.python.org/3.4/library/io.html#io.RawIOBase.read
// "If the object is in non-blocking mode and no bytes are available,
// None is returned."
// This is actually very weird, as naive truth check will treat
// this as EOF.
return mp_const_none;
}
mp_raise_OSError(error);
} else {
vstr.len = out_sz;
if (stream_p->is_text) {
return mp_obj_new_str_from_vstr(&vstr);
} else {
return mp_obj_new_bytes_from_vstr(&vstr);
}
}
}
STATIC mp_obj_t stream_read(size_t n_args, const mp_obj_t *args) {
return stream_read_generic(n_args, args, MP_STREAM_RW_READ);
}
MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mp_stream_read_obj, 1, 2, stream_read);
STATIC mp_obj_t stream_read1(size_t n_args, const mp_obj_t *args) {
return stream_read_generic(n_args, args, MP_STREAM_RW_READ | MP_STREAM_RW_ONCE);
}
MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mp_stream_read1_obj, 1, 2, stream_read1);
mp_obj_t mp_stream_write(mp_obj_t self_in, const void *buf, size_t len, byte flags) {
int error;
mp_uint_t out_sz = mp_stream_rw(self_in, (void *)buf, len, &error, flags);
if (error != 0) {
if (mp_is_nonblocking_error(error)) {
// http://docs.python.org/3/library/io.html#io.RawIOBase.write
// "None is returned if the raw stream is set not to block and
// no single byte could be readily written to it."
return mp_const_none;
}
mp_raise_OSError(error);
} else {
return MP_OBJ_NEW_SMALL_INT(out_sz);
}
}
// This is used to adapt a stream object to an mp_print_t interface
void mp_stream_write_adaptor(void *self, const char *buf, size_t len) {
mp_stream_write(MP_OBJ_FROM_PTR(self), buf, len, MP_STREAM_RW_WRITE);
}
STATIC mp_obj_t stream_write_method(size_t n_args, const mp_obj_t *args) {
mp_buffer_info_t bufinfo;
mp_get_buffer_raise(args[1], &bufinfo, MP_BUFFER_READ);
size_t max_len = (size_t)-1;
size_t off = 0;
if (n_args == 3) {
max_len = mp_obj_get_int_truncated(args[2]);
} else if (n_args == 4) {
off = mp_obj_get_int_truncated(args[2]);
max_len = mp_obj_get_int_truncated(args[3]);
if (off > bufinfo.len) {
off = bufinfo.len;
}
}
bufinfo.len -= off;
return mp_stream_write(args[0], (byte *)bufinfo.buf + off, MIN(bufinfo.len, max_len), MP_STREAM_RW_WRITE);
}
MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mp_stream_write_obj, 2, 4, stream_write_method);
STATIC mp_obj_t stream_write1_method(mp_obj_t self_in, mp_obj_t arg) {
mp_buffer_info_t bufinfo;
mp_get_buffer_raise(arg, &bufinfo, MP_BUFFER_READ);
return mp_stream_write(self_in, bufinfo.buf, bufinfo.len, MP_STREAM_RW_WRITE | MP_STREAM_RW_ONCE);
}
MP_DEFINE_CONST_FUN_OBJ_2(mp_stream_write1_obj, stream_write1_method);
STATIC mp_obj_t stream_readinto(size_t n_args, const mp_obj_t *args) {
mp_buffer_info_t bufinfo;
mp_get_buffer_raise(args[1], &bufinfo, MP_BUFFER_WRITE);
// CPython extension: if 2nd arg is provided, that's max len to read,
// instead of full buffer. Similar to
// https://docs.python.org/3/library/socket.html#socket.socket.recv_into
mp_uint_t len = bufinfo.len;
if (n_args > 2) {
len = mp_obj_get_int(args[2]);
if (len > bufinfo.len) {
len = bufinfo.len;
}
}
int error;
mp_uint_t out_sz = mp_stream_read_exactly(args[0], bufinfo.buf, len, &error);
if (error != 0) {
if (mp_is_nonblocking_error(error)) {
return mp_const_none;
}
mp_raise_OSError(error);
} else {
return MP_OBJ_NEW_SMALL_INT(out_sz);
}
}
MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mp_stream_readinto_obj, 2, 3, stream_readinto);
STATIC mp_obj_t stream_readall(mp_obj_t self_in) {
const mp_stream_p_t *stream_p = mp_get_stream(self_in);
mp_uint_t total_size = 0;
vstr_t vstr;
vstr_init(&vstr, DEFAULT_BUFFER_SIZE);
char *p = vstr.buf;
mp_uint_t current_read = DEFAULT_BUFFER_SIZE;
while (true) {
int error;
mp_uint_t out_sz = stream_p->read(self_in, p, current_read, &error);
if (out_sz == MP_STREAM_ERROR) {
if (mp_is_nonblocking_error(error)) {
// With non-blocking streams, we read as much as we can.
// If we read nothing, return None, just like read().
// Otherwise, return data read so far.
if (total_size == 0) {
return mp_const_none;
}
break;
}
mp_raise_OSError(error);
}
if (out_sz == 0) {
break;
}
total_size += out_sz;
if (out_sz < current_read) {
current_read -= out_sz;
p += out_sz;
} else {
p = vstr_extend(&vstr, DEFAULT_BUFFER_SIZE);
current_read = DEFAULT_BUFFER_SIZE;
}
}
vstr.len = total_size;
if (stream_p->is_text) {
return mp_obj_new_str_from_vstr(&vstr);
} else {
return mp_obj_new_bytes_from_vstr(&vstr);
}
}
// Unbuffered, inefficient implementation of readline() for raw I/O files.
STATIC mp_obj_t stream_unbuffered_readline(size_t n_args, const mp_obj_t *args) {
const mp_stream_p_t *stream_p = mp_get_stream(args[0]);
mp_int_t max_size = -1;
if (n_args > 1) {
max_size = MP_OBJ_SMALL_INT_VALUE(args[1]);
}
vstr_t vstr;
if (max_size != -1) {
vstr_init(&vstr, max_size);
} else {
vstr_init(&vstr, 16);
}
while (max_size == -1 || max_size-- != 0) {
char *p = vstr_add_len(&vstr, 1);
int error;
mp_uint_t out_sz = stream_p->read(args[0], p, 1, &error);
if (out_sz == MP_STREAM_ERROR) {
if (mp_is_nonblocking_error(error)) {
if (vstr.len == 1) {
// We just incremented it, but otherwise we read nothing
// and immediately got EAGAIN. This case is not well
// specified in
// https://docs.python.org/3/library/io.html#io.IOBase.readline
// unlike similar case for read(). But we follow the latter's
// behavior - return None.
vstr_clear(&vstr);
return mp_const_none;
} else {
goto done;
}
}
mp_raise_OSError(error);
}
if (out_sz == 0) {
done:
// Back out previously added byte
// Consider, what's better - read a char and get OutOfMemory (so read
// char is lost), or allocate first as we do.
vstr_cut_tail_bytes(&vstr, 1);
break;
}
if (*p == '\n') {
break;
}
}
if (stream_p->is_text) {
return mp_obj_new_str_from_vstr(&vstr);
} else {
return mp_obj_new_bytes_from_vstr(&vstr);
}
}
MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mp_stream_unbuffered_readline_obj, 1, 2, stream_unbuffered_readline);
// TODO take an optional extra argument (what does it do exactly?)
STATIC mp_obj_t stream_unbuffered_readlines(mp_obj_t self) {
mp_obj_t lines = mp_obj_new_list(0, NULL);
for (;;) {
mp_obj_t line = stream_unbuffered_readline(1, &self);
if (!mp_obj_is_true(line)) {
break;
}
mp_obj_list_append(lines, line);
}
return lines;
}
MP_DEFINE_CONST_FUN_OBJ_1(mp_stream_unbuffered_readlines_obj, stream_unbuffered_readlines);
mp_obj_t mp_stream_unbuffered_iter(mp_obj_t self) {
mp_obj_t l_in = stream_unbuffered_readline(1, &self);
if (mp_obj_is_true(l_in)) {
return l_in;
}
return MP_OBJ_STOP_ITERATION;
}
mp_obj_t mp_stream_close(mp_obj_t stream) {
const mp_stream_p_t *stream_p = mp_get_stream(stream);
int error;
mp_uint_t res = stream_p->ioctl(stream, MP_STREAM_CLOSE, 0, &error);
if (res == MP_STREAM_ERROR) {
mp_raise_OSError(error);
}
return mp_const_none;
}
MP_DEFINE_CONST_FUN_OBJ_1(mp_stream_close_obj, mp_stream_close);
STATIC mp_obj_t stream_seek(size_t n_args, const mp_obj_t *args) {
struct mp_stream_seek_t seek_s;
// TODO: Could be uint64
seek_s.offset = mp_obj_get_int(args[1]);
seek_s.whence = SEEK_SET;
if (n_args == 3) {
seek_s.whence = mp_obj_get_int(args[2]);
}
// In POSIX, it's error to seek before end of stream, we enforce it here.
if (seek_s.whence == SEEK_SET && seek_s.offset < 0) {
mp_raise_OSError(MP_EINVAL);
}
const mp_stream_p_t *stream_p = mp_get_stream(args[0]);
int error;
mp_uint_t res = stream_p->ioctl(args[0], MP_STREAM_SEEK, (mp_uint_t)(uintptr_t)&seek_s, &error);
if (res == MP_STREAM_ERROR) {
mp_raise_OSError(error);
}
// TODO: Could be uint64
return mp_obj_new_int_from_uint(seek_s.offset);
}
MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mp_stream_seek_obj, 2, 3, stream_seek);
STATIC mp_obj_t stream_tell(mp_obj_t self) {
mp_obj_t offset = MP_OBJ_NEW_SMALL_INT(0);
mp_obj_t whence = MP_OBJ_NEW_SMALL_INT(SEEK_CUR);
const mp_obj_t args[3] = {self, offset, whence};
return stream_seek(3, args);
}
MP_DEFINE_CONST_FUN_OBJ_1(mp_stream_tell_obj, stream_tell);
mp_obj_t mp_stream_flush(mp_obj_t self) {
const mp_stream_p_t *stream_p = mp_get_stream(self);
int error;
mp_uint_t res = stream_p->ioctl(self, MP_STREAM_FLUSH, 0, &error);
if (res == MP_STREAM_ERROR) {
mp_raise_OSError(error);
}
return mp_const_none;
}
MP_DEFINE_CONST_FUN_OBJ_1(mp_stream_flush_obj, stream_flush);
STATIC mp_obj_t stream_ioctl(size_t n_args, const mp_obj_t *args) {
mp_buffer_info_t bufinfo;
uintptr_t val = 0;
if (n_args > 2) {
if (mp_get_buffer(args[2], &bufinfo, MP_BUFFER_WRITE)) {
val = (uintptr_t)bufinfo.buf;
} else {
val = mp_obj_get_int_truncated(args[2]);
}
}
const mp_stream_p_t *stream_p = mp_get_stream(args[0]);
int error;
mp_uint_t res = stream_p->ioctl(args[0], mp_obj_get_int(args[1]), val, &error);
if (res == MP_STREAM_ERROR) {
mp_raise_OSError(error);
}
return mp_obj_new_int(res);
}
MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mp_stream_ioctl_obj, 2, 3, stream_ioctl);
#if MICROPY_STREAMS_POSIX_API
/*
* POSIX-like functions
*
* These functions have POSIX-compatible signature (except for "void *stream"
* first argument instead of "int fd"). They are useful to port existing
* POSIX-compatible software to work with MicroPython streams.
*/
#include <errno.h>
ssize_t mp_stream_posix_write(void *stream, const void *buf, size_t len) {
mp_obj_base_t *o = stream;
const mp_stream_p_t *stream_p = MP_OBJ_TYPE_GET_SLOT(o->type, protocol);
mp_uint_t out_sz = stream_p->write(MP_OBJ_FROM_PTR(stream), buf, len, &errno);
if (out_sz == MP_STREAM_ERROR) {
return -1;
} else {
return out_sz;
}
}
ssize_t mp_stream_posix_read(void *stream, void *buf, size_t len) {
mp_obj_base_t *o = stream;
const mp_stream_p_t *stream_p = MP_OBJ_TYPE_GET_SLOT(o->type, protocol);
mp_uint_t out_sz = stream_p->read(MP_OBJ_FROM_PTR(stream), buf, len, &errno);
if (out_sz == MP_STREAM_ERROR) {
return -1;
} else {
return out_sz;
}
}
off_t mp_stream_posix_lseek(void *stream, off_t offset, int whence) {
const mp_obj_base_t *o = stream;
const mp_stream_p_t *stream_p = MP_OBJ_TYPE_GET_SLOT(o->type, protocol);
struct mp_stream_seek_t seek_s;
seek_s.offset = offset;
seek_s.whence = whence;
mp_uint_t res = stream_p->ioctl(MP_OBJ_FROM_PTR(stream), MP_STREAM_SEEK, (mp_uint_t)(uintptr_t)&seek_s, &errno);
if (res == MP_STREAM_ERROR) {
return -1;
}
return seek_s.offset;
}
int mp_stream_posix_fsync(void *stream) {
mp_obj_base_t *o = stream;
const mp_stream_p_t *stream_p = MP_OBJ_TYPE_GET_SLOT(o->type, protocol);
mp_uint_t res = stream_p->ioctl(MP_OBJ_FROM_PTR(stream), MP_STREAM_FLUSH, 0, &errno);
if (res == MP_STREAM_ERROR) {
return -1;
}
return res;
}
#endif
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