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circuitpython/py/builtinimport.c
Damien George 78d702c300 py: Allow builtins to be overridden. 
This patch adds a configuration option (MICROPY_CAN_OVERRIDE_BUILTINS)
which, when enabled, allows to override all names within the builtins
module.  A builtins override dict is created the first time the user
assigns to a name in the builtins model, and then that dict is searched
first on subsequent lookups.  Note that this implementation doesn't
allow deleting of names.

This patch also does some refactoring of builtins code, creating the
modbuiltins.c file.

Addresses issue #959.
2014-12-09 16:19:48 +00:00

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/*
* 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 <stdint.h>
#include <stdio.h>
#include <string.h>
#include <assert.h>
#include "mpconfig.h"
#include "nlr.h"
#include "misc.h"
#include "qstr.h"
#include "lexer.h"
#include "lexerunix.h"
#include "parse.h"
#include "obj.h"
#include "objmodule.h"
#include "parsehelper.h"
#include "compile.h"
#include "runtime0.h"
#include "runtime.h"
#include "builtin.h"
#if 0 // print debugging info
#define DEBUG_PRINT (1)
#define DEBUG_printf DEBUG_printf
#else // don't print debugging info
#define DEBUG_PRINT (0)
#define DEBUG_printf(...) (void)0
#endif
#define PATH_SEP_CHAR '/'
#if MICROPY_MODULE_WEAK_LINKS
STATIC const mp_map_elem_t mp_builtin_module_weak_links_table[] = {
MICROPY_PORT_BUILTIN_MODULE_WEAK_LINKS
};
STATIC MP_DEFINE_CONST_MAP(mp_builtin_module_weak_links_map, mp_builtin_module_weak_links_table);
#endif
bool mp_obj_is_package(mp_obj_t module) {
mp_obj_t dest[2];
mp_load_method_maybe(module, MP_QSTR___path__, dest);
return dest[0] != MP_OBJ_NULL;
}
STATIC mp_import_stat_t stat_dir_or_file(vstr_t *path) {
//printf("stat %s\n", vstr_str(path));
mp_import_stat_t stat = mp_import_stat(vstr_str(path));
if (stat == MP_IMPORT_STAT_DIR) {
return stat;
}
vstr_add_str(path, ".py");
stat = mp_import_stat(vstr_str(path));
if (stat == MP_IMPORT_STAT_FILE) {
return stat;
}
return MP_IMPORT_STAT_NO_EXIST;
}
STATIC mp_import_stat_t find_file(const char *file_str, uint file_len, vstr_t *dest) {
#if MICROPY_PY_SYS
// extract the list of paths
mp_uint_t path_num;
mp_obj_t *path_items;
mp_obj_list_get(mp_sys_path, &path_num, &path_items);
if (path_num == 0) {
#endif
// mp_sys_path is empty, so just use the given file name
vstr_add_strn(dest, file_str, file_len);
return stat_dir_or_file(dest);
#if MICROPY_PY_SYS
} else {
// go through each path looking for a directory or file
for (mp_uint_t i = 0; i < path_num; i++) {
vstr_reset(dest);
mp_uint_t p_len;
const char *p = mp_obj_str_get_data(path_items[i], &p_len);
if (p_len > 0) {
vstr_add_strn(dest, p, p_len);
vstr_add_char(dest, PATH_SEP_CHAR);
}
vstr_add_strn(dest, file_str, file_len);
mp_import_stat_t stat = stat_dir_or_file(dest);
if (stat != MP_IMPORT_STAT_NO_EXIST) {
return stat;
}
}
// could not find a directory or file
return MP_IMPORT_STAT_NO_EXIST;
}
#endif
}
STATIC void do_load(mp_obj_t module_obj, vstr_t *file) {
// create the lexer
mp_lexer_t *lex = mp_lexer_new_from_file(vstr_str(file));
if (lex == NULL) {
// we verified the file exists using stat, but lexer could still fail
if (MICROPY_ERROR_REPORTING == MICROPY_ERROR_REPORTING_TERSE) {
nlr_raise(mp_obj_new_exception_msg(&mp_type_ImportError, "module not found"));
} else {
nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ImportError,
"no module named '%s'", vstr_str(file)));
}
}
#if MICROPY_PY___FILE__
qstr source_name = lex->source_name;
mp_store_attr(module_obj, MP_QSTR___file__, MP_OBJ_NEW_QSTR(source_name));
#endif
// parse, compile and execute the module in its context
mp_obj_dict_t *mod_globals = mp_obj_module_get_globals(module_obj);
mp_parse_compile_execute(lex, MP_PARSE_FILE_INPUT, mod_globals, mod_globals);
}
mp_obj_t mp_builtin___import__(mp_uint_t n_args, const mp_obj_t *args) {
#if DEBUG_PRINT
DEBUG_printf("__import__:\n");
for (mp_uint_t i = 0; i < n_args; i++) {
DEBUG_printf(" ");
mp_obj_print(args[i], PRINT_REPR);
DEBUG_printf("\n");
}
#endif
mp_obj_t module_name = args[0];
mp_obj_t fromtuple = mp_const_none;
mp_int_t level = 0;
if (n_args >= 4) {
fromtuple = args[3];
if (n_args >= 5) {
level = MP_OBJ_SMALL_INT_VALUE(args[4]);
}
}
mp_uint_t mod_len;
const char *mod_str = mp_obj_str_get_data(module_name, &mod_len);
if (level != 0) {
// What we want to do here is to take name of current module,
// chop <level> trailing components, and concatenate with passed-in
// module name, thus resolving relative import name into absolue.
// This even appears to be correct per
// http://legacy.python.org/dev/peps/pep-0328/#relative-imports-and-name
// "Relative imports use a module's __name__ attribute to determine that
// module's position in the package hierarchy."
mp_obj_t this_name_q = mp_obj_dict_get(mp_globals_get(), MP_OBJ_NEW_QSTR(MP_QSTR___name__));
assert(this_name_q != MP_OBJ_NULL);
#if DEBUG_PRINT
DEBUG_printf("Current module: ");
mp_obj_print(this_name_q, PRINT_REPR);
DEBUG_printf("\n");
#endif
mp_uint_t this_name_l;
const char *this_name = mp_obj_str_get_data(this_name_q, &this_name_l);
uint dots_seen = 0;
const char *p = this_name + this_name_l - 1;
while (p > this_name) {
if (*p == '.') {
dots_seen++;
if (--level == 0) {
break;
}
}
p--;
}
if (dots_seen == 0 && level == 1) {
// http://legacy.python.org/dev/peps/pep-0328/#relative-imports-and-name
// "If the module's name does not contain any package information
// (e.g. it is set to '__main__') then relative imports are
// resolved as if the module were a top level module, regardless
// of where the module is actually located on the file system."
// Supposedly this if catches this condition and resolve it properly
// TODO: But nobody knows for sure. This condition happens when
// package's __init__.py does something like "import .submod". So,
// maybe we should check for package here? But quote above doesn't
// talk about packages, it talks about dot-less module names.
p = this_name + this_name_l;
} else if (level != 0) {
nlr_raise(mp_obj_new_exception_msg(&mp_type_ImportError, "Invalid relative import"));
}
uint new_mod_l = (mod_len == 0 ? p - this_name : p - this_name + 1 + mod_len);
char *new_mod = alloca(new_mod_l);
memcpy(new_mod, this_name, p - this_name);
if (mod_len != 0) {
new_mod[p - this_name] = '.';
memcpy(new_mod + (p - this_name) + 1, mod_str, mod_len);
}
qstr new_mod_q = qstr_from_strn(new_mod, new_mod_l);
DEBUG_printf("Resolved relative name: %s\n", qstr_str(new_mod_q));
module_name = MP_OBJ_NEW_QSTR(new_mod_q);
mod_str = new_mod;
mod_len = new_mod_l;
}
// check if module already exists
mp_obj_t module_obj = mp_module_get(mp_obj_str_get_qstr(module_name));
if (module_obj != MP_OBJ_NULL) {
DEBUG_printf("Module already loaded\n");
// If it's not a package, return module right away
char *p = strchr(mod_str, '.');
if (p == NULL) {
return module_obj;
}
// If fromlist is not empty, return leaf module
if (fromtuple != mp_const_none) {
return module_obj;
}
// Otherwise, we need to return top-level package
qstr pkg_name = qstr_from_strn(mod_str, p - mod_str);
return mp_module_get(pkg_name);
}
DEBUG_printf("Module not yet loaded\n");
uint last = 0;
VSTR_FIXED(path, MICROPY_ALLOC_PATH_MAX)
module_obj = MP_OBJ_NULL;
mp_obj_t top_module_obj = MP_OBJ_NULL;
mp_obj_t outer_module_obj = MP_OBJ_NULL;
uint i;
for (i = 1; i <= mod_len; i++) {
if (i == mod_len || mod_str[i] == '.') {
// create a qstr for the module name up to this depth
qstr mod_name = qstr_from_strn(mod_str, i);
DEBUG_printf("Processing module: %s\n", qstr_str(mod_name));
DEBUG_printf("Previous path: %s\n", vstr_str(&path));
// find the file corresponding to the module name
mp_import_stat_t stat;
if (vstr_len(&path) == 0) {
// first module in the dotted-name; search for a directory or file
stat = find_file(mod_str, i, &path);
} else {
// latter module in the dotted-name; append to path
vstr_add_char(&path, PATH_SEP_CHAR);
vstr_add_strn(&path, mod_str + last, i - last);
stat = stat_dir_or_file(&path);
}
DEBUG_printf("Current path: %s\n", vstr_str(&path));
if (stat == MP_IMPORT_STAT_NO_EXIST) {
#if MICROPY_MODULE_WEAK_LINKS
// check if there is a weak link to this module
if (i == mod_len) {
mp_map_elem_t *el = mp_map_lookup((mp_map_t*)&mp_builtin_module_weak_links_map, MP_OBJ_NEW_QSTR(mod_name), MP_MAP_LOOKUP);
if (el == NULL) {
goto no_exist;
}
// found weak linked module
module_obj = el->value;
} else {
no_exist:
#else
{
#endif
// couldn't find the file, so fail
if (MICROPY_ERROR_REPORTING == MICROPY_ERROR_REPORTING_TERSE) {
nlr_raise(mp_obj_new_exception_msg(&mp_type_ImportError, "module not found"));
} else {
nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ImportError,
"no module named '%s'", qstr_str(mod_name)));
}
}
} else {
// found the file, so get the module
module_obj = mp_module_get(mod_name);
}
if (module_obj == MP_OBJ_NULL) {
// module not already loaded, so load it!
module_obj = mp_obj_new_module(mod_name);
// if args[3] (fromtuple) has magic value False, set up
// this module for command-line "-m" option (set module's
// name to __main__ instead of real name).
if (i == mod_len && fromtuple == mp_const_false) {
mp_obj_module_t *o = module_obj;
mp_obj_dict_store(o->globals, MP_OBJ_NEW_QSTR(MP_QSTR___name__), MP_OBJ_NEW_QSTR(MP_QSTR___main__));
}
if (stat == MP_IMPORT_STAT_DIR) {
DEBUG_printf("%s is dir\n", vstr_str(&path));
// https://docs.python.org/3/reference/import.html
// "Specifically, any module that contains a __path__ attribute is considered a package."
mp_store_attr(module_obj, MP_QSTR___path__, mp_obj_new_str(vstr_str(&path), vstr_len(&path), false));
vstr_add_char(&path, PATH_SEP_CHAR);
vstr_add_str(&path, "__init__.py");
if (mp_import_stat(vstr_str(&path)) != MP_IMPORT_STAT_FILE) {
vstr_cut_tail_bytes(&path, sizeof("/__init__.py") - 1); // cut off /__init__.py
printf("Notice: %s is imported as namespace package\n", vstr_str(&path));
} else {
do_load(module_obj, &path);
vstr_cut_tail_bytes(&path, sizeof("/__init__.py") - 1); // cut off /__init__.py
}
} else { // MP_IMPORT_STAT_FILE
do_load(module_obj, &path);
// TODO: We cannot just break here, at the very least, we must execute
// trailer code below. But otherwise if there're remaining components,
// that would be (??) object path within module, not modules path within FS.
// break;
}
}
if (outer_module_obj != MP_OBJ_NULL) {
qstr s = qstr_from_strn(mod_str + last, i - last);
mp_store_attr(outer_module_obj, s, module_obj);
}
outer_module_obj = module_obj;
if (top_module_obj == MP_OBJ_NULL) {
top_module_obj = module_obj;
}
last = i + 1;
}
}
if (i < mod_len) {
// we loaded a package, now need to load objects from within that package
// TODO
assert(0);
}
// If fromlist is not empty, return leaf module
if (fromtuple != mp_const_none) {
return module_obj;
}
// Otherwise, we need to return top-level package
return top_module_obj;
}
MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mp_builtin___import___obj, 1, 5, mp_builtin___import__);
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