micropython/py/stream.c

231 wiersze
8.6 KiB
C
Czysty Zwykły widok Historia

/*
* This file is part of the Micro Python project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2013, 2014 Damien P. George
*
* 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 <errno.h>
#include "mpconfig.h"
#include "nlr.h"
#include "misc.h"
#include "qstr.h"
#include "obj.h"
#include "stream.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);
// TODO: This is POSIX-specific (but then POSIX is the only real thing,
// and anything else just emulates it, right?)
#define is_nonblocking_error(errno) ((errno) == EAGAIN || (errno) == EWOULDBLOCK)
STATIC mp_obj_t stream_read(uint n_args, const mp_obj_t *args) {
struct _mp_obj_base_t *o = (struct _mp_obj_base_t *)args[0];
if (o->type->stream_p == NULL || o->type->stream_p->read == NULL) {
// CPython: io.UnsupportedOperation, OSError subclass
nlr_raise(mp_obj_new_exception_msg(&mp_type_OSError, "Operation not supported"));
}
machine_int_t sz;
if (n_args == 1 || ((sz = mp_obj_get_int(args[1])) == -1)) {
return stream_readall(args[0]);
}
byte *buf = m_new(byte, sz);
int error;
machine_int_t out_sz = o->type->stream_p->read(o, buf, sz, &error);
if (out_sz == -1) {
if (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;
}
nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_OSError, "[Errno %d]", error));
} else {
mp_obj_t s = mp_obj_new_str(buf, out_sz, false); // will reallocate to use exact size
m_free(buf, sz);
return s;
}
}
STATIC mp_obj_t stream_write(mp_obj_t self_in, mp_obj_t arg) {
struct _mp_obj_base_t *o = (struct _mp_obj_base_t *)self_in;
if (o->type->stream_p == NULL || o->type->stream_p->write == NULL) {
// CPython: io.UnsupportedOperation, OSError subclass
nlr_raise(mp_obj_new_exception_msg(&mp_type_OSError, "Operation not supported"));
}
mp_buffer_info_t bufinfo;
mp_get_buffer_raise(arg, &bufinfo, MP_BUFFER_READ);
int error;
machine_int_t out_sz = o->type->stream_p->write(self_in, bufinfo.buf, bufinfo.len, &error);
if (out_sz == -1) {
if (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."
// This is for consistency with read() behavior, still weird,
// see abobe.
return mp_const_none;
}
nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_OSError, "[Errno %d]", error));
} else {
return MP_OBJ_NEW_SMALL_INT(out_sz);
}
}
STATIC mp_obj_t stream_readall(mp_obj_t self_in) {
struct _mp_obj_base_t *o = (struct _mp_obj_base_t *)self_in;
if (o->type->stream_p == NULL || o->type->stream_p->read == NULL) {
// CPython: io.UnsupportedOperation, OSError subclass
nlr_raise(mp_obj_new_exception_msg(&mp_type_OSError, "Operation not supported"));
}
int total_size = 0;
vstr_t *vstr = vstr_new_size(DEFAULT_BUFFER_SIZE);
char *buf = vstr_str(vstr);
char *p = buf;
int error;
int current_read = DEFAULT_BUFFER_SIZE;
while (true) {
machine_int_t out_sz = o->type->stream_p->read(self_in, p, current_read, &error);
if (out_sz == -1) {
if (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;
}
nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_OSError, "[Errno %d]", error));
}
if (out_sz == 0) {
break;
}
total_size += out_sz;
if (out_sz < current_read) {
current_read -= out_sz;
p += out_sz;
} else {
current_read = DEFAULT_BUFFER_SIZE;
p = vstr_extend(vstr, current_read);
if (p == NULL) {
// TODO
nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_OSError/*&mp_type_RuntimeError*/, "Out of memory"));
}
}
}
mp_obj_t s = mp_obj_new_str((byte*)vstr->buf, total_size, false);
vstr_free(vstr);
return s;
}
// Unbuffered, inefficient implementation of readline() for raw I/O files.
STATIC mp_obj_t stream_unbuffered_readline(uint n_args, const mp_obj_t *args) {
struct _mp_obj_base_t *o = (struct _mp_obj_base_t *)args[0];
if (o->type->stream_p == NULL || o->type->stream_p->read == NULL) {
// CPython: io.UnsupportedOperation, OSError subclass
nlr_raise(mp_obj_new_exception_msg(&mp_type_OSError, "Operation not supported"));
}
machine_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 = vstr_new_size(max_size);
} else {
vstr = vstr_new();
}
int error;
while (max_size == -1 || max_size-- != 0) {
char *p = vstr_add_len(vstr, 1);
if (p == NULL) {
nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_MemoryError, "out of memory"));
}
machine_int_t out_sz = o->type->stream_p->read(o, p, 1, &error);
if (out_sz == -1) {
nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_OSError, "[Errno %d]", error));
}
if (out_sz == 0) {
// Back out previously added byte
// TODO: This is a bit hacky, does it supported by vstr API contract?
// Consider, what's better - read a char and get OutOfMemory (so read
// char is lost), or allocate first as we do.
vstr_add_len(vstr, -1);
break;
}
if (*p == '\n') {
break;
}
}
// TODO need a string creation API that doesn't copy the given data
mp_obj_t ret = mp_obj_new_str((byte*)vstr->buf, vstr->len, false);
vstr_free(vstr);
return ret;
}
// 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_str_get_len(line) == 0) {
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_str_get_len(l_in) != 0) {
return l_in;
}
return MP_OBJ_STOP_ITERATION;
}
MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mp_stream_read_obj, 1, 2, stream_read);
MP_DEFINE_CONST_FUN_OBJ_1(mp_stream_readall_obj, stream_readall);
MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mp_stream_unbuffered_readline_obj, 1, 2, stream_unbuffered_readline);
MP_DEFINE_CONST_FUN_OBJ_2(mp_stream_write_obj, stream_write);