file.c

#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <sys/stat.h>
#include <sys/types.h>

#include "mpconfig.h"
#include "nlr.h"
#include "misc.h"
#include "qstr.h"
#include "obj.h"
#include "runtime.h"
#include "stream.h"

typedef struct _mp_obj_fdfile_t {
    mp_obj_base_t base;
    int fd;
} mp_obj_fdfile_t;

#ifdef MICROPY_CPYTHON_COMPAT
void check_fd_is_open(const mp_obj_fdfile_t *o) {
    if (o->fd < 0)
        nlr_raise(mp_obj_new_exception_msg(&mp_type_ValueError, "I/O operation on closed file"));
}
#else
#define check_fd_is_open(o)
#endif

STATIC const mp_obj_type_t rawfile_type;

STATIC void fdfile_print(void (*print)(void *env, const char *fmt, ...), void *env, mp_obj_t self_in, mp_print_kind_t kind) {
    mp_obj_fdfile_t *self = self_in;
    print(env, "<io.FileIO %d>", self->fd);
}

STATIC machine_int_t fdfile_read(mp_obj_t o_in, void *buf, machine_uint_t size, int *errcode) {
    mp_obj_fdfile_t *o = o_in;
    check_fd_is_open(o);
    machine_int_t r = read(o->fd, buf, size);
    if (r == -1) {
        *errcode = errno;
    }
    return r;
}

STATIC machine_int_t fdfile_write(mp_obj_t o_in, const void *buf, machine_uint_t size, int *errcode) {
    mp_obj_fdfile_t *o = o_in;
    check_fd_is_open(o);
    machine_int_t r = write(o->fd, buf, size);
    if (r == -1) {
        *errcode = errno;
    }
    return r;
}

STATIC mp_obj_t fdfile_close(mp_obj_t self_in) {
    mp_obj_fdfile_t *self = self_in;
    close(self->fd);
#ifdef MICROPY_CPYTHON_COMPAT
    self->fd = -1;
#endif
    return mp_const_none;
}
STATIC MP_DEFINE_CONST_FUN_OBJ_1(fdfile_close_obj, fdfile_close);

mp_obj_t fdfile___exit__(uint n_args, const mp_obj_t *args) {
    return fdfile_close(args[0]);
}
STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(fdfile___exit___obj, 4, 4, fdfile___exit__);

STATIC mp_obj_t fdfile_fileno(mp_obj_t self_in) {
    mp_obj_fdfile_t *self = self_in;
    check_fd_is_open(self);
    return MP_OBJ_NEW_SMALL_INT((machine_int_t)self->fd);
}
STATIC MP_DEFINE_CONST_FUN_OBJ_1(fdfile_fileno_obj, fdfile_fileno);

STATIC mp_obj_fdfile_t *fdfile_new(int fd) {
    mp_obj_fdfile_t *o = m_new_obj(mp_obj_fdfile_t);
    o->base.type = &rawfile_type;
    o->fd = fd;
    return o;
}

STATIC mp_obj_t fdfile_make_new(mp_obj_t type_in, uint n_args, uint n_kw, const mp_obj_t *args) {
    mp_obj_fdfile_t *o = m_new_obj(mp_obj_fdfile_t);
    o->base.type = type_in;

    if (MP_OBJ_IS_SMALL_INT(args[0])) {
        o->fd = MP_OBJ_SMALL_INT_VALUE(args[0]);
        return o;
    }

    const char *fname = mp_obj_str_get_str(args[0]);
    const char *mode_s;
    if (n_args > 1) {
        mode_s = mp_obj_str_get_str(args[1]);
    } else {
        mode_s = "r";
    }

    int mode = 0;
    while (*mode_s) {
        switch (*mode_s++) {
            // Note: these assume O_RDWR = O_RDONLY | O_WRONLY
            case 'r':
                mode |= O_RDONLY;
                break;
            case 'w':
                mode |= O_WRONLY | O_CREAT | O_TRUNC;
                break;
            case 'a':
                mode |= O_APPEND;
                break;
            case '+':
                mode |= O_RDWR;
                break;
        }
    }

    int fd = open(fname, mode, 0644);
    if (fd == -1) {
        nlr_raise(mp_obj_new_exception_arg1(&mp_type_OSError, MP_OBJ_NEW_SMALL_INT((machine_int_t)errno)));
    }
    return fdfile_new(fd);
}

STATIC const mp_map_elem_t rawfile_locals_dict_table[] = {
    { MP_OBJ_NEW_QSTR(MP_QSTR_fileno), (mp_obj_t)&fdfile_fileno_obj },
    { MP_OBJ_NEW_QSTR(MP_QSTR_read), (mp_obj_t)&mp_stream_read_obj },
    { MP_OBJ_NEW_QSTR(MP_QSTR_readall), (mp_obj_t)&mp_stream_readall_obj },
    { MP_OBJ_NEW_QSTR(MP_QSTR_readline), (mp_obj_t)&mp_stream_unbuffered_readline_obj},
    { MP_OBJ_NEW_QSTR(MP_QSTR_write), (mp_obj_t)&mp_stream_write_obj },
    { MP_OBJ_NEW_QSTR(MP_QSTR_close), (mp_obj_t)&fdfile_close_obj },
    { MP_OBJ_NEW_QSTR(MP_QSTR___enter__), (mp_obj_t)&mp_identity_obj },
    { MP_OBJ_NEW_QSTR(MP_QSTR___exit__), (mp_obj_t)&fdfile___exit___obj },
};

STATIC MP_DEFINE_CONST_DICT(rawfile_locals_dict, rawfile_locals_dict_table);

STATIC const mp_stream_p_t rawfile_stream_p = {
    .read = fdfile_read,
    .write = fdfile_write,
};

STATIC const mp_obj_type_t rawfile_type = {
    { &mp_type_type },
    .name = MP_QSTR_FileIO,
    .print = fdfile_print,
    .make_new = fdfile_make_new,
    .getiter = mp_identity,
    .iternext = mp_stream_unbuffered_iter,
    .stream_p = &rawfile_stream_p,
    .locals_dict = (mp_obj_t)&rawfile_locals_dict,
};

// Factory function for I/O stream classes
mp_obj_t mp_builtin_open(uint n_args, const mp_obj_t *args) {
    // TODO: analyze mode and buffering args and instantiate appropriate type
    return fdfile_make_new((mp_obj_t)&rawfile_type, n_args, 0, args);
}
MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mp_builtin_open_obj, 1, 2, mp_builtin_open);

const mp_obj_fdfile_t mp_sys_stdin_obj  = { .base = {&rawfile_type}, .fd = STDIN_FILENO };
const mp_obj_fdfile_t mp_sys_stdout_obj = { .base = {&rawfile_type}, .fd = STDOUT_FILENO };
const mp_obj_fdfile_t mp_sys_stderr_obj = { .base = {&rawfile_type}, .fd = STDERR_FILENO };