1# Copyright 2019 The Chromium Authors 2# Use of this source code is governed by a BSD-style license that can be 3# found in the LICENSE file. 4 5"""Basic .ini encoding and decoding. 6 7The basic element in an ini file is the key. Every key is constructed by a name 8and a value, delimited by an equals sign (=). 9 10Keys may be grouped into sections. The secetion name will be a line by itself, 11in square brackets ([ and ]). All keys after the section are associated with 12that section until another section occurs. 13 14Keys that are not under any section are considered at the top level. 15 16Section and key names are case sensitive. 17""" 18 19 20import contextlib 21import os 22 23 24def add_key(line, config, strict=True): 25 key, val = line.split('=', 1) 26 key = key.strip() 27 val = val.strip() 28 if strict and key in config: 29 raise ValueError('Multiple entries present for key "%s"' % key) 30 config[key] = val 31 32 33def loads(ini_str, strict=True): 34 """Deserialize int_str to a dict (nested dict when has sections) object. 35 36 Duplicated sections will merge their keys. 37 38 When there are multiple entries for a key, at the top level, or under the 39 same section: 40 - If strict is true, ValueError will be raised. 41 - If strict is false, only the last occurrence will be stored. 42 """ 43 ret = {} 44 section = None 45 for line in ini_str.splitlines(): 46 # Empty line 47 if not line: 48 continue 49 # Section line 50 if line[0] == '[' and line[-1] == ']': 51 section = line[1:-1] 52 if section not in ret: 53 ret[section] = {} 54 # Key line 55 else: 56 config = ret if section is None else ret[section] 57 add_key(line, config, strict=strict) 58 59 return ret 60 61 62def load(fp): 63 return loads(fp.read()) 64 65 66def dumps(obj): 67 results = [] 68 key_str = '' 69 70 for k, v in sorted(obj.items()): 71 if isinstance(v, dict): 72 results.append('[%s]\n' % k + dumps(v)) 73 else: 74 key_str += '%s = %s\n' % (k, str(v)) 75 76 # Insert key_str at the first position, before any sections 77 if key_str: 78 results.insert(0, key_str) 79 80 return '\n'.join(results) 81 82 83def dump(obj, fp): 84 fp.write(dumps(obj)) 85 86 87@contextlib.contextmanager 88def update_ini_file(ini_file_path): 89 """Load and update the contents of an ini file. 90 91 Args: 92 ini_file_path: A string containing the absolute path of the ini file. 93 Yields: 94 The contents of the file, as a dict 95 """ 96 ini_contents = {} 97 if os.path.exists(ini_file_path): 98 with open(ini_file_path) as ini_file: 99 ini_contents = load(ini_file) 100 101 yield ini_contents 102 103 with open(ini_file_path, 'w') as ini_file: 104 dump(ini_contents, ini_file) 105