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objgenerator.c

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  • objgenerator.c 9.29 KiB
    /*
     * This file is part of the Micro Python project, http://micropython.org/
     *
     * The MIT License (MIT)
     *
     * Copyright (c) 2013, 2014 Damien P. George
     * Copyright (c) 2014 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 <stdlib.h>
    #include <assert.h>
    
    #include "py/nlr.h"
    #include "py/obj.h"
    #include "py/runtime.h"
    #include "py/bc.h"
    #include "py/objgenerator.h"
    #include "py/objfun.h"
    
    /******************************************************************************/
    /* generator wrapper                                                          */
    
    typedef struct _mp_obj_gen_wrap_t {
        mp_obj_base_t base;
        mp_obj_t *fun;
    } mp_obj_gen_wrap_t;
    
    typedef struct _mp_obj_gen_instance_t {
        mp_obj_base_t base;
        mp_obj_dict_t *globals;
        mp_code_state code_state;
    } mp_obj_gen_instance_t;
    
    STATIC mp_obj_t gen_wrap_call(mp_obj_t self_in, mp_uint_t n_args, mp_uint_t n_kw, const mp_obj_t *args) {
        mp_obj_gen_wrap_t *self = self_in;
        mp_obj_fun_bc_t *self_fun = (mp_obj_fun_bc_t*)self->fun;
        assert(MP_OBJ_IS_TYPE(self_fun, &mp_type_fun_bc));
    
        // skip code-info block
        const byte *code_info = self_fun->bytecode;
        mp_uint_t code_info_size = mp_decode_uint(&code_info);
        const byte *ip = self_fun->bytecode + code_info_size;
    
        // bytecode prelude: skip arg names
        ip += (self_fun->n_pos_args + self_fun->n_kwonly_args) * sizeof(mp_obj_t);
    
        // bytecode prelude: get state size and exception stack size
        mp_uint_t n_state = mp_decode_uint(&ip);
        mp_uint_t n_exc_stack = mp_decode_uint(&ip);
    
        // allocate the generator object, with room for local stack and exception stack
        mp_obj_gen_instance_t *o = m_new_obj_var(mp_obj_gen_instance_t, byte,
            n_state * sizeof(mp_obj_t) + n_exc_stack * sizeof(mp_exc_stack_t));
        o->base.type = &mp_type_gen_instance;
    
        o->globals = self_fun->globals;
        o->code_state.n_state = n_state;
        o->code_state.ip = ip;
        mp_setup_code_state(&o->code_state, self_fun, n_args, n_kw, args);
        return o;
    }
    
    const mp_obj_type_t mp_type_gen_wrap = {
        { &mp_type_type },
        .name = MP_QSTR_generator,
        .call = gen_wrap_call,
    };
    
    mp_obj_t mp_obj_new_gen_wrap(mp_obj_t fun) {
        mp_obj_gen_wrap_t *o = m_new_obj(mp_obj_gen_wrap_t);
        o->base.type = &mp_type_gen_wrap;
        o->fun = fun;
        return o;
    }
    
    /******************************************************************************/
    /* generator instance                                                         */
    
    STATIC void gen_instance_print(void (*print)(void *env, const char *fmt, ...), void *env, mp_obj_t self_in, mp_print_kind_t kind) {
        (void)kind;
        mp_obj_gen_instance_t *self = self_in;
        print(env, "<generator object '%s' at %p>", qstr_str(mp_obj_code_get_name(self->code_state.code_info)), self_in);
    }
    
    mp_vm_return_kind_t mp_obj_gen_resume(mp_obj_t self_in, mp_obj_t send_value, mp_obj_t throw_value, mp_obj_t *ret_val) {
        assert(MP_OBJ_IS_TYPE(self_in, &mp_type_gen_instance));
        mp_obj_gen_instance_t *self = self_in;
        if (self->code_state.ip == 0) {
            *ret_val = MP_OBJ_STOP_ITERATION;
            return MP_VM_RETURN_NORMAL;
        }
        if (self->code_state.sp == self->code_state.state - 1) {
            if (send_value != mp_const_none) {
                nlr_raise(mp_obj_new_exception_msg(&mp_type_TypeError, "can't send non-None value to a just-started generator"));
            }
        } else {
            *self->code_state.sp = send_value;
        }
        mp_obj_dict_t *old_globals = mp_globals_get();
        mp_globals_set(self->globals);
        mp_vm_return_kind_t ret_kind = mp_execute_bytecode(&self->code_state, throw_value);
        mp_globals_set(old_globals);
    
        switch (ret_kind) {
            case MP_VM_RETURN_NORMAL:
            default:
                // Explicitly mark generator as completed. If we don't do this,
                // subsequent next() may re-execute statements after last yield
                // again and again, leading to side effects.
                // TODO: check how return with value behaves under such conditions
                // in CPython.
                self->code_state.ip = 0;
                *ret_val = *self->code_state.sp;
                break;
    
            case MP_VM_RETURN_YIELD:
                *ret_val = *self->code_state.sp;
                break;
    
            case MP_VM_RETURN_EXCEPTION:
                self->code_state.ip = 0;
                *ret_val = self->code_state.state[self->code_state.n_state - 1];
                break;
        }
    
        return ret_kind;
    }
    
    STATIC mp_obj_t gen_resume_and_raise(mp_obj_t self_in, mp_obj_t send_value, mp_obj_t throw_value) {
        mp_obj_t ret;
        switch (mp_obj_gen_resume(self_in, send_value, throw_value, &ret)) {
            case MP_VM_RETURN_NORMAL:
            default:
                // Optimize return w/o value in case generator is used in for loop
                if (ret == mp_const_none || ret == MP_OBJ_STOP_ITERATION) {
                    return MP_OBJ_STOP_ITERATION;
                } else {
                    nlr_raise(mp_obj_new_exception_args(&mp_type_StopIteration, 1, &ret));
                }
    
            case MP_VM_RETURN_YIELD:
                if (throw_value != MP_OBJ_NULL && mp_obj_is_subclass_fast(mp_obj_get_type(throw_value), &mp_type_GeneratorExit)) {
                    nlr_raise(mp_obj_new_exception_msg(&mp_type_RuntimeError, "generator ignored GeneratorExit"));
                }
                return ret;
    
            case MP_VM_RETURN_EXCEPTION:
                // TODO: Optimization of returning MP_OBJ_STOP_ITERATION is really part
                // of mp_iternext() protocol, but this function is called by other methods
                // too, which may not handled MP_OBJ_STOP_ITERATION.
                if (mp_obj_is_subclass_fast(mp_obj_get_type(ret), &mp_type_StopIteration)) {
                    return MP_OBJ_STOP_ITERATION;
                } else {
                    nlr_raise(ret);
                }
        }
    }
    
    STATIC mp_obj_t gen_instance_iternext(mp_obj_t self_in) {
        return gen_resume_and_raise(self_in, mp_const_none, MP_OBJ_NULL);
    }
    
    STATIC mp_obj_t gen_instance_send(mp_obj_t self_in, mp_obj_t send_value) {
        mp_obj_t ret = gen_resume_and_raise(self_in, send_value, MP_OBJ_NULL);
        if (ret == MP_OBJ_STOP_ITERATION) {
            nlr_raise(mp_obj_new_exception(&mp_type_StopIteration));
        } else {
            return ret;
        }
    }
    
    STATIC MP_DEFINE_CONST_FUN_OBJ_2(gen_instance_send_obj, gen_instance_send);
    
    STATIC mp_obj_t gen_instance_close(mp_obj_t self_in);
    STATIC mp_obj_t gen_instance_throw(mp_uint_t n_args, const mp_obj_t *args) {
        mp_obj_t exc = (n_args == 2) ? args[1] : args[2];
        exc = mp_make_raise_obj(exc);
    
        mp_obj_t ret = gen_resume_and_raise(args[0], mp_const_none, exc);
        if (ret == MP_OBJ_STOP_ITERATION) {
            nlr_raise(mp_obj_new_exception(&mp_type_StopIteration));
        } else {
            return ret;
        }
    }
    
    STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(gen_instance_throw_obj, 2, 4, gen_instance_throw);
    
    STATIC mp_obj_t gen_instance_close(mp_obj_t self_in) {
        mp_obj_t ret;
        switch (mp_obj_gen_resume(self_in, mp_const_none, (mp_obj_t)&mp_const_GeneratorExit_obj, &ret)) {
            case MP_VM_RETURN_YIELD:
                nlr_raise(mp_obj_new_exception_msg(&mp_type_RuntimeError, "generator ignored GeneratorExit"));
    
            // Swallow StopIteration & GeneratorExit (== successful close), and re-raise any other
            case MP_VM_RETURN_EXCEPTION:
                // ret should always be an instance of an exception class
                if (mp_obj_is_subclass_fast(mp_obj_get_type(ret), &mp_type_GeneratorExit) ||
                    mp_obj_is_subclass_fast(mp_obj_get_type(ret), &mp_type_StopIteration)) {
                    return mp_const_none;
                }
                nlr_raise(ret);
    
            default:
                // The only choice left is MP_VM_RETURN_NORMAL which is successful close
                return mp_const_none;
        }
    }
    
    STATIC MP_DEFINE_CONST_FUN_OBJ_1(gen_instance_close_obj, gen_instance_close);
    
    STATIC const mp_map_elem_t gen_instance_locals_dict_table[] = {
        { MP_OBJ_NEW_QSTR(MP_QSTR_close), (mp_obj_t)&gen_instance_close_obj },
        { MP_OBJ_NEW_QSTR(MP_QSTR_send), (mp_obj_t)&gen_instance_send_obj },
        { MP_OBJ_NEW_QSTR(MP_QSTR_throw), (mp_obj_t)&gen_instance_throw_obj },
    };
    
    STATIC MP_DEFINE_CONST_DICT(gen_instance_locals_dict, gen_instance_locals_dict_table);
    
    const mp_obj_type_t mp_type_gen_instance = {
        { &mp_type_type },
        .name = MP_QSTR_generator,
        .print = gen_instance_print,
        .getiter = mp_identity,
        .iternext = gen_instance_iternext,
        .locals_dict = (mp_obj_t)&gen_instance_locals_dict,
    };