micropython/py/reader.c
Damien George 1831034be1 py: Allow lexer to raise exceptions during construction.
This patch refactors the error handling in the lexer, to simplify it (ie
reduce code size).

A long time ago, when the lexer/parser/compiler were first written, the
lexer and parser were designed so they didn't use exceptions (ie nlr) to
report errors but rather returned an error code.  Over time that has
gradually changed, the parser in particular has more and more ways of
raising exceptions.  Also, the lexer never really handled all errors without
raising, eg there were some memory errors which could raise an exception
(and in these rare cases one would get a fatal nlr-not-handled fault).

This patch accepts the fact that the lexer can raise exceptions in some
cases and allows it to raise exceptions to handle all its errors, which are
for the most part just out-of-memory errors during construction of the
lexer.  This makes the lexer a bit simpler, and also the persistent code
stuff is simplified.

What this means for users of the lexer is that calls to it must be wrapped
in a nlr handler.  But all uses of the lexer already have such an nlr
handler for the parser (and compiler) so that doesn't put any extra burden
on the callers.
2017-03-14 11:52:05 +11:00

137 lines
4.0 KiB
C

/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2013-2016 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 <stdio.h>
#include <assert.h>
#include "py/runtime.h"
#include "py/mperrno.h"
#include "py/reader.h"
typedef struct _mp_reader_mem_t {
size_t free_len; // if >0 mem is freed on close by: m_free(beg, free_len)
const byte *beg;
const byte *cur;
const byte *end;
} mp_reader_mem_t;
STATIC mp_uint_t mp_reader_mem_readbyte(void *data) {
mp_reader_mem_t *reader = (mp_reader_mem_t*)data;
if (reader->cur < reader->end) {
return *reader->cur++;
} else {
return MP_READER_EOF;
}
}
STATIC void mp_reader_mem_close(void *data) {
mp_reader_mem_t *reader = (mp_reader_mem_t*)data;
if (reader->free_len > 0) {
m_del(char, (char*)reader->beg, reader->free_len);
}
m_del_obj(mp_reader_mem_t, reader);
}
void mp_reader_new_mem(mp_reader_t *reader, const byte *buf, size_t len, size_t free_len) {
mp_reader_mem_t *rm = m_new_obj(mp_reader_mem_t);
rm->free_len = free_len;
rm->beg = buf;
rm->cur = buf;
rm->end = buf + len;
reader->data = rm;
reader->readbyte = mp_reader_mem_readbyte;
reader->close = mp_reader_mem_close;
}
#if MICROPY_READER_POSIX
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
typedef struct _mp_reader_posix_t {
bool close_fd;
int fd;
size_t len;
size_t pos;
byte buf[20];
} mp_reader_posix_t;
STATIC mp_uint_t mp_reader_posix_readbyte(void *data) {
mp_reader_posix_t *reader = (mp_reader_posix_t*)data;
if (reader->pos >= reader->len) {
if (reader->len == 0) {
return MP_READER_EOF;
} else {
int n = read(reader->fd, reader->buf, sizeof(reader->buf));
if (n <= 0) {
reader->len = 0;
return MP_READER_EOF;
}
reader->len = n;
reader->pos = 0;
}
}
return reader->buf[reader->pos++];
}
STATIC void mp_reader_posix_close(void *data) {
mp_reader_posix_t *reader = (mp_reader_posix_t*)data;
if (reader->close_fd) {
close(reader->fd);
}
m_del_obj(mp_reader_posix_t, reader);
}
void mp_reader_new_file_from_fd(mp_reader_t *reader, int fd, bool close_fd) {
mp_reader_posix_t *rp = m_new_obj(mp_reader_posix_t);
rp->close_fd = close_fd;
rp->fd = fd;
int n = read(rp->fd, rp->buf, sizeof(rp->buf));
if (n == -1) {
if (close_fd) {
close(fd);
}
mp_raise_OSError(errno);
}
rp->len = n;
rp->pos = 0;
reader->data = rp;
reader->readbyte = mp_reader_posix_readbyte;
reader->close = mp_reader_posix_close;
}
void mp_reader_new_file(mp_reader_t *reader, const char *filename) {
int fd = open(filename, O_RDONLY, 0644);
if (fd < 0) {
mp_raise_OSError(errno);
}
mp_reader_new_file_from_fd(reader, fd, true);
}
#endif