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micropython/py/objgenerator.c

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/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2013-2019 Damien P. George
* Copyright (c) 2014-2017 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/runtime.h"
#include "py/bc.h"
#include "py/objstr.h"
#include "py/objgenerator.h"
#include "py/objfun.h"
#include "py/stackctrl.h"
// Instance of GeneratorExit exception - needed by generator.close()
const mp_obj_exception_t mp_const_GeneratorExit_obj = {{&mp_type_GeneratorExit}, 0, 0, NULL, (mp_obj_tuple_t *)&mp_const_empty_tuple_obj};
/******************************************************************************/
/* generator wrapper */
typedef struct _mp_obj_gen_instance_t {
mp_obj_base_t base;
// mp_const_none: Not-running, no exception.
// MP_OBJ_NULL: Running, no exception.
// other: Not running, pending exception.
mp_obj_t pend_exc;
mp_code_state_t code_state;
} mp_obj_gen_instance_t;
STATIC mp_obj_t gen_wrap_call(mp_obj_t self_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
// A generating function is just a bytecode function with type mp_type_gen_wrap
mp_obj_fun_bc_t *self_fun = MP_OBJ_TO_PTR(self_in);
// bytecode prelude: get state size and exception stack size
const uint8_t *ip = self_fun->bytecode;
MP_BC_PRELUDE_SIG_DECODE(ip);
// allocate the generator object, with room for local stack and exception stack
mp_obj_gen_instance_t *o = mp_obj_malloc_var(mp_obj_gen_instance_t, byte,
n_state * sizeof(mp_obj_t) + n_exc_stack * sizeof(mp_exc_stack_t),
&mp_type_gen_instance);
o->pend_exc = mp_const_none;
o->code_state.fun_bc = self_fun;
o->code_state.n_state = n_state;
mp_setup_code_state(&o->code_state, n_args, n_kw, args);
return MP_OBJ_FROM_PTR(o);
}
#if MICROPY_PY_FUNCTION_ATTRS
#define GEN_WRAP_TYPE_ATTR attr, mp_obj_fun_bc_attr,
#else
#define GEN_WRAP_TYPE_ATTR
#endif
MP_DEFINE_CONST_OBJ_TYPE(
mp_type_gen_wrap,
MP_QSTR_generator,
MP_TYPE_FLAG_BINDS_SELF,
GEN_WRAP_TYPE_ATTR
call, gen_wrap_call
);
/******************************************************************************/
// native generator wrapper
#if MICROPY_EMIT_NATIVE
// Based on mp_obj_gen_instance_t.
typedef struct _mp_obj_gen_instance_native_t {
mp_obj_base_t base;
mp_obj_t pend_exc;
mp_code_state_native_t code_state;
} mp_obj_gen_instance_native_t;
STATIC mp_obj_t native_gen_wrap_call(mp_obj_t self_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
// The state for a native generating function is held in the same struct as a bytecode function
mp_obj_fun_bc_t *self_fun = MP_OBJ_TO_PTR(self_in);
// Determine start of prelude.
uintptr_t prelude_ptr_index = ((uintptr_t *)self_fun->bytecode)[0];
const uint8_t *prelude_ptr;
if (prelude_ptr_index == 0) {
prelude_ptr = (void *)self_fun->child_table;
} else {
prelude_ptr = (void *)self_fun->child_table[prelude_ptr_index];
}
// Extract n_state from the prelude.
const uint8_t *ip = prelude_ptr;
MP_BC_PRELUDE_SIG_DECODE(ip);
// Allocate the generator object, with room for local stack (exception stack not needed).
mp_obj_gen_instance_native_t *o = mp_obj_malloc_var(mp_obj_gen_instance_native_t, byte, n_state * sizeof(mp_obj_t), &mp_type_gen_instance);
// Parse the input arguments and set up the code state
o->pend_exc = mp_const_none;
o->code_state.fun_bc = self_fun;
o->code_state.ip = prelude_ptr;
o->code_state.n_state = n_state;
o->code_state.sp = &o->code_state.state[0] - 1;
mp_setup_code_state_native(&o->code_state, n_args, n_kw, args);
// Indicate we are a native function, which doesn't use this variable
o->code_state.exc_sp_idx = MP_CODE_STATE_EXC_SP_IDX_SENTINEL;
// Prepare the generator instance for execution
uintptr_t start_offset = ((uintptr_t *)self_fun->bytecode)[1];
o->code_state.ip = MICROPY_MAKE_POINTER_CALLABLE((void *)(self_fun->bytecode + start_offset));
return MP_OBJ_FROM_PTR(o);
}
#if MICROPY_PY_FUNCTION_ATTRS
#define NATIVE_GEN_WRAP_TYPE_ATTR , attr, mp_obj_fun_bc_attr
#else
#define NATIVE_GEN_WRAP_TYPE_ATTR
#endif
MP_DEFINE_CONST_OBJ_TYPE(
mp_type_native_gen_wrap,
MP_QSTR_generator,
MP_TYPE_FLAG_BINDS_SELF,
call, native_gen_wrap_call
NATIVE_GEN_WRAP_TYPE_ATTR
);
#endif // MICROPY_EMIT_NATIVE
/******************************************************************************/
/* generator instance */
STATIC void gen_instance_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
(void)kind;
mp_obj_gen_instance_t *self = MP_OBJ_TO_PTR(self_in);
mp_printf(print, "<generator object '%q' at %p>", mp_obj_fun_get_name(MP_OBJ_FROM_PTR(self->code_state.fun_bc)), self);
}
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) {
MP_STACK_CHECK();
mp_check_self(mp_obj_is_type(self_in, &mp_type_gen_instance));
mp_obj_gen_instance_t *self = MP_OBJ_TO_PTR(self_in);
if (self->code_state.ip == 0) {
// Trying to resume an already stopped generator.
// This is an optimised "raise StopIteration(None)".
*ret_val = mp_const_none;
return MP_VM_RETURN_NORMAL;
}
// Ensure the generator cannot be reentered during execution
if (self->pend_exc == MP_OBJ_NULL) {
mp_raise_ValueError(MP_ERROR_TEXT("generator already executing"));
}
#if MICROPY_PY_GENERATOR_PEND_THROW
// If exception is pending (set using .pend_throw()), process it now.
if (self->pend_exc != mp_const_none) {
throw_value = self->pend_exc;
}
#endif
// If the generator is started, allow sending a value.
void *state_start = self->code_state.state - 1;
#if MICROPY_EMIT_NATIVE
if (self->code_state.exc_sp_idx == MP_CODE_STATE_EXC_SP_IDX_SENTINEL) {
state_start = ((mp_obj_gen_instance_native_t *)self)->code_state.state - 1;
}
#endif
if (self->code_state.sp == state_start) {
if (send_value != mp_const_none) {
mp_raise_TypeError(MP_ERROR_TEXT("can't send non-None value to a just-started generator"));
}
} else {
*self->code_state.sp = send_value;
}
// Mark as running
self->pend_exc = MP_OBJ_NULL;
// Set up the correct globals context for the generator and execute it
self->code_state.old_globals = mp_globals_get();
mp_globals_set(self->code_state.fun_bc->context->module.globals);
mp_vm_return_kind_t ret_kind;
#if MICROPY_EMIT_NATIVE
if (self->code_state.exc_sp_idx == MP_CODE_STATE_EXC_SP_IDX_SENTINEL) {
// A native generator, with entry point 2 words into the "bytecode" pointer
typedef uintptr_t (*mp_fun_native_gen_t)(void *, mp_obj_t);
mp_fun_native_gen_t fun = MICROPY_MAKE_POINTER_CALLABLE((const void *)(self->code_state.fun_bc->bytecode + 2 * sizeof(uintptr_t)));
ret_kind = fun((void *)&self->code_state, throw_value);
} else
#endif
{
// A bytecode generator
ret_kind = mp_execute_bytecode(&self->code_state, throw_value);
}
mp_globals_set(self->code_state.old_globals);
// Mark as not running
self->pend_exc = mp_const_none;
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.
self->code_state.ip = 0;
// This is an optimised "raise StopIteration(*ret_val)".
*ret_val = *self->code_state.sp;
break;
case MP_VM_RETURN_YIELD:
*ret_val = *self->code_state.sp;
#if MICROPY_PY_GENERATOR_PEND_THROW
*self->code_state.sp = mp_const_none;
#endif
break;
case MP_VM_RETURN_EXCEPTION: {
self->code_state.ip = 0;
#if MICROPY_EMIT_NATIVE
if (self->code_state.exc_sp_idx == MP_CODE_STATE_EXC_SP_IDX_SENTINEL) {
*ret_val = ((mp_obj_gen_instance_native_t *)self)->code_state.state[0];
} else
#endif
{
*ret_val = self->code_state.state[0];
}
// PEP479: if StopIteration is raised inside a generator it is replaced with RuntimeError
if (mp_obj_is_subclass_fast(MP_OBJ_FROM_PTR(mp_obj_get_type(*ret_val)), MP_OBJ_FROM_PTR(&mp_type_StopIteration))) {
*ret_val = mp_obj_new_exception_msg(&mp_type_RuntimeError, MP_ERROR_TEXT("generator raised StopIteration"));
}
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, bool raise_stop_iteration) {
mp_obj_t ret;
switch (mp_obj_gen_resume(self_in, send_value, throw_value, &ret)) {
case MP_VM_RETURN_NORMAL:
default:
// A normal return is a StopIteration, either raise it or return
// MP_OBJ_STOP_ITERATION as an optimisation.
if (ret == mp_const_none) {
ret = MP_OBJ_NULL;
}
if (raise_stop_iteration) {
mp_raise_StopIteration(ret);
} else {
return mp_make_stop_iteration(ret);
}
case MP_VM_RETURN_YIELD:
return ret;
case MP_VM_RETURN_EXCEPTION:
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, false);
}
STATIC mp_obj_t gen_instance_send(mp_obj_t self_in, mp_obj_t send_value) {
return gen_resume_and_raise(self_in, send_value, MP_OBJ_NULL, true);
}
STATIC MP_DEFINE_CONST_FUN_OBJ_2(gen_instance_send_obj, gen_instance_send);
STATIC mp_obj_t gen_instance_throw(size_t n_args, const mp_obj_t *args) {
// The signature of this function is: throw(type[, value[, traceback]])
// CPython will pass all given arguments through the call chain and process them
// at the point they are used (native generators will handle them differently to
// user-defined generators with a throw() method). To save passing multiple
// values, MicroPython instead does partial processing here to reduce it down to
// one argument and passes that through:
// - if only args[1] is given, or args[2] is given but is None, args[1] is
// passed through (in the standard case it is an exception class or instance)
// - if args[2] is given and not None it is passed through (in the standard
// case it would be an exception instance and args[1] its corresponding class)
// - args[3] is always ignored
mp_obj_t exc = args[1];
if (n_args > 2 && args[2] != mp_const_none) {
exc = args[2];
}
return gen_resume_and_raise(args[0], mp_const_none, exc, true);
}
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_FROM_PTR(&mp_const_GeneratorExit_obj), &ret)) {
case MP_VM_RETURN_YIELD:
mp_raise_msg(&mp_type_RuntimeError, MP_ERROR_TEXT("generator ignored GeneratorExit"));
// Swallow 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_FROM_PTR(mp_obj_get_type(ret)), MP_OBJ_FROM_PTR(&mp_type_GeneratorExit))) {
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);
#if MICROPY_PY_GENERATOR_PEND_THROW
STATIC mp_obj_t gen_instance_pend_throw(mp_obj_t self_in, mp_obj_t exc_in) {
mp_obj_gen_instance_t *self = MP_OBJ_TO_PTR(self_in);
if (self->pend_exc == MP_OBJ_NULL) {
mp_raise_ValueError(MP_ERROR_TEXT("generator already executing"));
}
mp_obj_t prev = self->pend_exc;
self->pend_exc = exc_in;
return prev;
}
STATIC MP_DEFINE_CONST_FUN_OBJ_2(gen_instance_pend_throw_obj, gen_instance_pend_throw);
#endif
STATIC const mp_rom_map_elem_t gen_instance_locals_dict_table[] = {
{ MP_ROM_QSTR(MP_QSTR_close), MP_ROM_PTR(&gen_instance_close_obj) },
{ MP_ROM_QSTR(MP_QSTR_send), MP_ROM_PTR(&gen_instance_send_obj) },
{ MP_ROM_QSTR(MP_QSTR_throw), MP_ROM_PTR(&gen_instance_throw_obj) },
#if MICROPY_PY_GENERATOR_PEND_THROW
{ MP_ROM_QSTR(MP_QSTR_pend_throw), MP_ROM_PTR(&gen_instance_pend_throw_obj) },
#endif
};
STATIC MP_DEFINE_CONST_DICT(gen_instance_locals_dict, gen_instance_locals_dict_table);
MP_DEFINE_CONST_OBJ_TYPE(
mp_type_gen_instance,
MP_QSTR_generator,
MP_TYPE_FLAG_ITER_IS_ITERNEXT,
print, gen_instance_print,
iter, gen_instance_iternext,
locals_dict, &gen_instance_locals_dict
);
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