1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
|
% Licensed under the Apache License, Version 2.0 (the "License"); you may not
% use this file except in compliance with the License. You may obtain a copy of
% the License at
%
% http://www.apache.org/licenses/LICENSE-2.0
%
% Unless required by applicable law or agreed to in writing, software
% distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
% WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
% License for the specific language governing permissions and limitations under
% the License.
%% @doc Saves a Key/Value pair to a ini file. The Key consists of a Module
%% and Variable combination. If that combination is found in the ini file
%% the new value replaces the old value. If only the Module is found the
%% Variable and value combination is appended to the Module. If the Module
%% does not yet exist in the ini file, it is added and the Variable/Value
%% pair is appended.
%% @see couch_config
-module(couch_config_writer).
-include("couch_db.hrl").
-export([save_to_file/2]).
%% @spec save_to_file(
%% Config::{{Module::string(), Variable::string()}, Value::string()},
%% File::filename()) -> ok
%% @doc Saves a Module/Key/Value triple to the ini file File::filename()
save_to_file({{Module, Variable}, Value}, File) ->
?LOG_DEBUG("saving to file '~s', Config: '~p'", [File, {{Module, Variable}, Value}]),
% open file and create a list of lines
{ok, Stream} = file:read_file(File),
OldFileContents = binary_to_list(Stream),
{ok, Lines} = regexp:split(OldFileContents, "\r\n|\n|\r|\032"),
% prepare input variables
ModuleName = "[" ++ Module ++ "]",
VariableList = Variable,
% produce the contents for the config file
NewFileContents =
case NewFileContents2 = save_loop({{ModuleName, VariableList}, Value}, Lines, "", "", []) of
% we didn't change anything, that means we couldn't find a matching
% [ini section] in which case we just append a new one.
OldFileContents ->
append_new_ini_section({{ModuleName, VariableList}, Value}, OldFileContents);
_ ->
NewFileContents2
end,
% do the save, close the config file and get out
save_file(File, NewFileContents),
file:close(Stream),
ok.
%% @doc Iterates over the lines of an ini file and replaces or adds a new
%% configuration directive.
save_loop({{Module, Variable}, Value}, [Line|Rest], OldCurrentModule, Contents, DoneVariables) ->
% if we find a new [ini section] (Module), save that for reference
NewCurrentModule = parse_module(Line, OldCurrentModule),
% if the current Module is the one we want to change, try to match
% each line with the Variable
NewContents = case Module of
NewCurrentModule ->
% see if the current line matches the variable we want to substitute
case parse_variable(Line, Variable, Value) of
% nope, return original line
nomatch ->
DoneVariables2 = DoneVariables,
Line;
% got em! return new line
NewLine ->
DoneVariables2 = [Variable|DoneVariables],
NewLine
end;
% if the variable we want to change couldn't be replaced, we append it
% in the proper module section
OldCurrentModule ->
case lists:member(Variable, DoneVariables) of
false ->
DoneVariables2 = [Variable|DoneVariables],
Variable ++ " = " ++ Value ++ "\n" ++ Line;
true ->
DoneVariables2 = DoneVariables,
Line
end;
% otherwise we just print out the original line
_ ->
DoneVariables2 = DoneVariables,
Line
end,
% clumsy way to only append a newline character
% if the line is not empty. We need this to not
% avoid haveing a newline inserted at the top
% of the target file each time we save it.
Contents2 = case Contents of "" -> ""; _ -> Contents ++ "\n" end,
% go to next line
save_loop({{Module, Variable}, Value}, Rest, NewCurrentModule, Contents2 ++ NewContents, DoneVariables2);
save_loop(_Config, [], _OldModule, NewFileContents, _DoneVariable) ->
% we're out of new lines, just return the new file's contents
NewFileContents.
append_new_ini_section({{ModuleName, Variable}, Value}, OldFileContents) ->
OldFileContents ++ "\n\n" ++ ModuleName ++ "\n" ++ Variable ++ " = " ++ Value ++ "\n".
%% @spec parse_module(Lins::string(), OldModule::string()) -> string()
%% @doc Tries to match a line against a pattern specifying a ini module or
%% section ("[Module]"). Returns OldModule if no match is found.
parse_module(Line, OldModule) ->
case regexp:match(Line, "^\\[([a-zA-Z0-9_-]*)\\]$") of
nomatch ->
OldModule;
{error, Error} ->
io:format("ini file regex error module: '~s'~n", [Error]),
OldModule;
{match, Start, Length} ->
string:substr(Line, Start, Length)
end.
%% @spec parse_variable(Line::string(), Variable::string(), Value::string()) ->
%% string() | nomatch
%% @doc Tries to match a variable assignment in Line. Returns nomatch if the
%% Variable is not found. Returns a new line composed of the Variable and
%% Value otherwise.
parse_variable(Line, Variable, Value) ->
case regexp:match(Line, "^" ++ Variable ++ "\s?=") of
nomatch ->
nomatch;
{error, Error}->
io:format("ini file regex error variable: '~s'~n", [Error]),
nomatch;
{match, _Start, _Length} ->
Variable ++ " = " ++ Value
end.
%% @spec save_file(File::filename(), Contents::string()) ->
%% ok | {error, Reason::string()}
%% @doc Writes Contents to File
save_file(File, Contents) ->
file:write_file(File, list_to_binary(Contents)).
|
