Diff: py/builtinimport.c

Revision:

0:5868e8752d44

Child:

2:c89e95946844

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/py/builtinimport.c	Sat Apr 16 17:11:56 2016 +0000
@@ -0,0 +1,477 @@
+/*
+ * 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 <stdio.h>
+#include <string.h>
+#include <assert.h>
+
+#include "py/nlr.h"
+#include "py/compile.h"
+#include "py/objmodule.h"
+#include "py/runtime.h"
+#include "py/builtin.h"
+#include "py/frozenmod.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_rom_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) {
+    mp_import_stat_t stat = mp_import_stat(vstr_null_terminated_str(path));
+    DEBUG_printf("stat %s: %d\n", vstr_str(path), stat);
+    if (stat == MP_IMPORT_STAT_DIR) {
+        return stat;
+    }
+
+    vstr_add_str(path, ".py");
+    stat = mp_import_stat(vstr_null_terminated_str(path));
+    if (stat == MP_IMPORT_STAT_FILE) {
+        return stat;
+    }
+
+    #if MICROPY_PERSISTENT_CODE_LOAD
+    vstr_ins_byte(path, path->len - 2, 'm');
+    stat = mp_import_stat(vstr_null_terminated_str(path));
+    if (stat == MP_IMPORT_STAT_FILE) {
+        return stat;
+    }
+    #endif
+
+    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
+}
+
+#if MICROPY_ENABLE_COMPILER
+STATIC void do_load_from_lexer(mp_obj_t module_obj, mp_lexer_t *lex, const char *fname) {
+
+    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'", fname));
+        }
+    }
+
+    #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);
+}
+#endif
+
+#if MICROPY_PERSISTENT_CODE_LOAD
+STATIC void do_execute_raw_code(mp_obj_t module_obj, mp_raw_code_t *raw_code) {
+    #if MICROPY_PY___FILE__
+    // TODO
+    //qstr source_name = lex->source_name;
+    //mp_store_attr(module_obj, MP_QSTR___file__, MP_OBJ_NEW_QSTR(source_name));
+    #endif
+
+    // execute the module in its context
+    mp_obj_dict_t *mod_globals = mp_obj_module_get_globals(module_obj);
+
+    // save context
+    mp_obj_dict_t *volatile old_globals = mp_globals_get();
+    mp_obj_dict_t *volatile old_locals = mp_locals_get();
+
+    // set new context
+    mp_globals_set(mod_globals);
+    mp_locals_set(mod_globals);
+
+    nlr_buf_t nlr;
+    if (nlr_push(&nlr) == 0) {
+        mp_obj_t module_fun = mp_make_function_from_raw_code(raw_code, MP_OBJ_NULL, MP_OBJ_NULL);
+        mp_call_function_0(module_fun);
+
+        // finish nlr block, restore context
+        nlr_pop();
+        mp_globals_set(old_globals);
+        mp_locals_set(old_locals);
+    } else {
+        // exception; restore context and re-raise same exception
+        mp_globals_set(old_globals);
+        mp_locals_set(old_locals);
+        nlr_jump(nlr.ret_val);
+    }
+}
+#endif
+
+STATIC void do_load(mp_obj_t module_obj, vstr_t *file) {
+    // create the lexer
+    char *file_str = vstr_null_terminated_str(file);
+
+    #if MICROPY_PERSISTENT_CODE_LOAD
+    if (file_str[file->len - 3] == 'm') {
+        mp_raw_code_t *raw_code = mp_raw_code_load_file(file_str);
+        do_execute_raw_code(module_obj, raw_code);
+        return;
+    }
+    #endif
+
+    #if MICROPY_ENABLE_COMPILER
+    {
+        mp_lexer_t *lex = mp_lexer_new_from_file(file_str);
+        do_load_from_lexer(module_obj, lex, file_str);
+    }
+    #else
+    nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ImportError,
+        "script compilation not supported"));
+    #endif
+}
+
+STATIC void chop_component(const char *start, const char **end) {
+    const char *p = *end;
+    while (p > start) {
+        if (*--p == '.') {
+            *end = p;
+            return;
+        }
+    }
+    *end = p;
+}
+
+mp_obj_t mp_builtin___import__(size_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."
+        level--;
+        mp_obj_t this_name_q = mp_obj_dict_get(MP_OBJ_FROM_PTR(mp_globals_get()), MP_OBJ_NEW_QSTR(MP_QSTR___name__));
+        assert(this_name_q != MP_OBJ_NULL);
+        #if MICROPY_CPYTHON_COMPAT
+        if (MP_OBJ_QSTR_VALUE(this_name_q) == MP_QSTR___main__) {
+            // This is a module run by -m command-line switch, get its real name from backup attribute
+            this_name_q = mp_obj_dict_get(MP_OBJ_FROM_PTR(mp_globals_get()), MP_OBJ_NEW_QSTR(MP_QSTR___main__));
+        }
+        #endif
+        mp_map_t *globals_map = &mp_globals_get()->map;
+        mp_map_elem_t *elem = mp_map_lookup(globals_map, MP_OBJ_NEW_QSTR(MP_QSTR___path__), MP_MAP_LOOKUP);
+        bool is_pkg = (elem != NULL);
+
+#if DEBUG_PRINT
+        DEBUG_printf("Current module/package: ");
+        mp_obj_print(this_name_q, PRINT_REPR);
+        DEBUG_printf(", is_package: %d", is_pkg);
+        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);
+
+        const char *p = this_name + this_name_l;
+        if (!is_pkg) {
+            // We have module, but relative imports are anchored at package, so
+            // go there.
+            chop_component(this_name, &p);
+        }
+
+
+        uint dots_seen = 0;
+        while (level--) {
+            chop_component(this_name, &p);
+            dots_seen++;
+        }
+
+        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.
+            DEBUG_printf("Warning: no dots in current module name and level>0\n");
+            p = this_name + this_name_l;
+        } else if (level != -1) {
+            nlr_raise(mp_obj_new_exception_msg(&mp_type_ImportError, "Invalid relative import"));
+        }
+
+        uint new_mod_l = (mod_len == 0 ? (size_t)(p - this_name) : (size_t)(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 base name for relative import: '%s'\n", qstr_str(new_mod_q));
+        if (new_mod_q == MP_QSTR_) {
+            // CPython raises SystemError
+            nlr_raise(mp_obj_new_exception_msg(&mp_type_ImportError, "cannot perform relative import"));
+        }
+        module_name = MP_OBJ_NEW_QSTR(new_mod_q);
+        mod_str = new_mod;
+        mod_len = new_mod_l;
+    }
+
+    // check if module already exists
+    qstr module_name_qstr = mp_obj_str_get_qstr(module_name);
+    mp_obj_t module_obj = mp_module_get(module_name_qstr);
+    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");
+
+    #if MICROPY_MODULE_FROZEN
+    mp_lexer_t *lex = mp_find_frozen_module(mod_str, mod_len);
+    if (lex != NULL) {
+        module_obj = mp_obj_new_module(module_name_qstr);
+        // 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).
+        // TODO: Duplicated below too.
+        if (fromtuple == mp_const_false) {
+            mp_obj_module_t *o = MP_OBJ_TO_PTR(module_obj);
+            mp_obj_dict_store(MP_OBJ_FROM_PTR(o->globals), MP_OBJ_NEW_QSTR(MP_QSTR___name__), MP_OBJ_NEW_QSTR(MP_QSTR___main__));
+        }
+        do_load_from_lexer(module_obj, lex, mod_str);
+        return module_obj;
+    }
+    #endif
+
+    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_len(&path), 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_len(&path), 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 '%q'", 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 = MP_OBJ_TO_PTR(module_obj);
+                    mp_obj_dict_store(MP_OBJ_FROM_PTR(o->globals), MP_OBJ_NEW_QSTR(MP_QSTR___name__), MP_OBJ_NEW_QSTR(MP_QSTR___main__));
+                    #if MICROPY_CPYTHON_COMPAT
+                    // Store real name in "__main__" attribute. Choosen semi-randonly, to reuse existing qstr's.
+                    mp_obj_dict_store(MP_OBJ_FROM_PTR(o->globals), MP_OBJ_NEW_QSTR(MP_QSTR___main__), MP_OBJ_NEW_QSTR(mod_name));
+                    #endif
+                }
+
+                if (stat == MP_IMPORT_STAT_DIR) {
+                    DEBUG_printf("%.*s is dir\n", vstr_len(&path), 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_null_terminated_str(&path)) != MP_IMPORT_STAT_FILE) {
+                        vstr_cut_tail_bytes(&path, sizeof("/__init__.py") - 1); // cut off /__init__.py
+                        mp_warning("%s is imported as namespace package", 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__);