circuitpython/shared-module/dotenv/__init__.c

313 lines
10 KiB
C

/*
* This file is part of the Micro Python project, http://micropython.org/
*
* The MIT License (MIT)
*
* SPDX-FileCopyrightText: Copyright (c) 2022 Scott Shawcroft for Adafruit Industries
*
* 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 <string.h>
#include "shared-bindings/dotenv/__init__.h"
#include "py/misc.h"
#include "py/mpstate.h"
#include "py/objstr.h"
#include "supervisor/filesystem.h"
#if defined(UNIX)
typedef FILE *file_arg;
STATIC bool open_file(const char *name, file_arg *active_file) {
FILE *result = fopen(name, "r");
if (result) {
*active_file = result;
}
return result != NULL;
}
STATIC void close_file(file_arg *active_file) {
fclose(*active_file);
}
STATIC uint8_t get_next_character(file_arg *active_file) {
int value = fgetc(*active_file);
if (value == EOF) {
return 0;
}
return value;
}
STATIC void seek_minus_one(file_arg *active_file) {
fseek(*active_file, -1, SEEK_CUR);
}
#else
#include "extmod/vfs.h"
#include "extmod/vfs_fat.h"
typedef FIL file_arg;
STATIC bool open_file(const char *name, file_arg *active_file) {
FATFS *fs = filesystem_circuitpy();
FRESULT result = f_open(fs, active_file, name, FA_READ);
return result == FR_OK;
}
STATIC void close_file(file_arg *active_file) {
// nothing
}
// Return 0 if there is no next character (EOF).
STATIC uint8_t get_next_character(FIL *active_file) {
uint8_t character = 0;
UINT quantity_read;
// If there's an error or quantity_read is 0, character will remain 0.
f_read(active_file, &character, 1, &quantity_read);
return character;
}
STATIC void seek_minus_one(file_arg *active_file) {
f_lseek(active_file, f_tell(active_file) - 1);
}
#endif
// Discard whitespace, except for newlines, returning the next character after the whitespace.
// Return 0 if there is no next character (EOF).
STATIC uint8_t consume_whitespace(file_arg *active_file) {
uint8_t character;
do {
character = get_next_character(active_file);
} while (character != '\n' && character != 0 && unichar_isspace(character));
return character;
}
// Starting at the start of a new line, determines if the key matches the given
// key. File pointer is set to be just before the = after the key.
STATIC bool key_matches(file_arg *active_file, const char *key) {
uint8_t character;
character = consume_whitespace(active_file);
if (character == 0) {
return false;
}
bool quoted = false;
if (character == '\'') {
// Beginning of single-quoted string.
quoted = true;
character = get_next_character(active_file);
}
size_t key_pos = 0;
bool escaped = false;
bool matches = true;
size_t key_len = strlen(key);
while (character != 0) {
if (character == '\\' && !escaped && quoted) {
escaped = true;
} else if (!escaped && quoted && character == '\'') {
quoted = false;
// End of quoted key. Skip over the ending quote.
character = get_next_character(active_file);
break;
} else if (!quoted && (unichar_isspace(character) || character == '=' || character == '\n' || character == '#' || character == 0)) {
// End of unquoted key.
break;
} else {
// Still on tentative key; see if it matches the next supplied key character,
// but don't run off the end of the supplied key.
if (key_pos < key_len) {
matches = matches && (unsigned char)key[key_pos] == character;
escaped = false;
key_pos++;
} else {
// Key on line is too long.
matches = false;
}
}
character = get_next_character(active_file);
}
if (character == '=' || character == '\n' || character == '#' || character == 0) {
// Rewind one so the value, if any, can be found.
seek_minus_one(active_file);
} else if (!unichar_isspace(character)) {
// We're followed by something else that is invalid syntax.
matches = false;
}
return matches && key_pos == key_len;
}
STATIC bool next_line(file_arg *active_file) {
uint8_t character;
bool quoted = false;
bool escaped = false;
// Track comments because they last until the end of the line.
bool comment = false;
// Consume all characters while quoted or others up to \n.
do {
character = get_next_character(active_file);
if ((!quoted || character == '#') || comment) {
// Comments consume any escaping.
comment = true;
} else if (!escaped) {
if (character == '\'') {
quoted = !quoted;
} else if (character == '\\') {
escaped = true;
}
} else {
escaped = false;
}
} while (character != 0 && (quoted || character != '\n'));
return character != 0;
}
STATIC mp_int_t read_value(file_arg *active_file, char *value, size_t value_len) {
uint8_t character;
// Consume spaces before "=", and get first character of interest.
character = consume_whitespace(active_file);
if (character != '=') {
if (character == '#' || character == '\n') {
// Keys without an = after them are valid with the value None.
return -1;
}
// All other characters are invalid.
return -1;
}
// Consume space after =
if (character != '#') {
// a # immediately after = is part of the value!
character = consume_whitespace(active_file);
}
bool quoted = false;
if (character == '\'') {
quoted = true;
character = get_next_character(active_file);
}
if (character == '"') {
// We don't support double quoted values.
return -1;
}
// Copy the value over.
size_t value_pos = 0;
bool escaped = false;
// Count trailing spaces so we can ignore them at the end of unquoted
// values.
size_t trailing_spaces = 0;
bool first_char = true;
while (character != 0) {
// Consume the first \ if the value is quoted.
if (quoted && character == '\\' && !escaped) {
escaped = true;
// Drop this backslash by short circuiting the rest of the loop.
character = get_next_character(active_file);
continue;
}
if (quoted && !escaped && character == '\'') {
// trailing ' means the value is done.
break;
}
// Unquoted values are ended by a newline or comment.
if (!quoted && (character == '\n' || (character == '#' && !first_char))) {
if (character == '\n') {
// Rewind one so the next_line can find the \n.
seek_minus_one(active_file);
}
break;
}
if (!quoted && unichar_isspace(character)) {
trailing_spaces += 1;
} else {
trailing_spaces = 0;
}
escaped = false;
// Only copy the value over if we have space. Otherwise, we'll just
// count the overall length.
if (value_pos < value_len) {
value[value_pos] = character;
}
value_pos++;
character = get_next_character(active_file);
first_char = false;
}
return value_pos - trailing_spaces;
}
mp_int_t dotenv_get_key(const char *path, const char *key, char *value, mp_int_t value_len) {
file_arg active_file;
if (!open_file(path, &active_file)) {
return -1;
}
mp_int_t actual_value_len = -1;
bool read_ok = true;
while (read_ok) {
if (key_matches(&active_file, key)) {
actual_value_len = read_value(&active_file, value, value_len);
}
read_ok = next_line(&active_file);
}
close_file(&active_file);
return actual_value_len;
}
mp_obj_t common_hal_dotenv_get_key(const char *path, const char *key) {
// Use the stack for short values. Longer values will require a heap allocation after we know
// the length.
char value[64];
mp_int_t actual_len = dotenv_get_key(path, key, value, sizeof(value));
if (actual_len < 0) {
return mp_const_none;
}
if ((size_t)actual_len >= sizeof(value)) {
byte *buf = m_new(byte, actual_len + 1);
dotenv_get_key(path, key, (char *)buf, actual_len);
buf[actual_len] = 0;
mp_obj_str_t *o = m_new_obj(mp_obj_str_t);
o->base.type = &mp_type_str;
o->len = actual_len;
o->data = buf;
o->hash = qstr_compute_hash(buf, actual_len);
return MP_OBJ_FROM_PTR(o);
}
return mp_obj_new_str(value, actual_len);
}
bool dotenv_get_key_terminated(const char *path, const char *key, char *value, mp_int_t value_len) {
mp_int_t actual_len = dotenv_get_key(path, key, value, value_len - 1);
if (actual_len >= value_len) {
return false;
}
value[actual_len] = '\0'; // terminate string
return true;
}
bool dotenv_get_key_int(const char *path, const char *key, mp_int_t *value) {
char buf[16];
if (!dotenv_get_key_terminated(path, key, buf, (mp_int_t)sizeof(buf))) {
return false;
}
char *end;
long result = strtol(buf, &end, 0);
if (end == buf || *end) { // If the whole buffer was not consumed it's an error
return false;
}
*value = (mp_int_t)result;
return true;
}