diff options
Diffstat (limited to 'apps/couch/src/couch_config_writer.erl')
-rw-r--r-- | apps/couch/src/couch_config_writer.erl | 79 |
1 files changed, 79 insertions, 0 deletions
diff --git a/apps/couch/src/couch_config_writer.erl b/apps/couch/src/couch_config_writer.erl new file mode 100644 index 00000000..c8691d79 --- /dev/null +++ b/apps/couch/src/couch_config_writer.erl @@ -0,0 +1,79 @@ +% 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 Section +%% and Option combination. If that combination is found in the ini file +%% the new value replaces the old value. If only the Section is found the +%% Option and value combination is appended to the Section. If the Section +%% does not yet exist in the ini file, it is added and the Option/Value +%% pair is appended. +%% @see couch_config + +-module(couch_config_writer). + +-export([save_to_file/2]). + +%% @spec save_to_file( +%% Config::{{Section::string(), Option::string()}, Value::string()}, +%% File::filename()) -> ok +%% @doc Saves a Section/Key/Value triple to the ini file File::filename() +save_to_file({{Section, Key}, Value}, File) -> + {ok, OldFileContents} = file:read_file(File), + Lines = re:split(OldFileContents, "\r\n|\n|\r|\032", [{return, list}]), + + SectionLine = "[" ++ Section ++ "]", + {ok, Pattern} = re:compile(["^(", Key, "\\s*=)|\\[[a-zA-Z0-9\_-]*\\]"]), + + NewLines = process_file_lines(Lines, [], SectionLine, Pattern, Key, Value), + NewFileContents = reverse_and_add_newline(strip_empty_lines(NewLines), []), + ok = file:write_file(File, NewFileContents). + + +process_file_lines([Section|Rest], SeenLines, Section, Pattern, Key, Value) -> + process_section_lines(Rest, [Section|SeenLines], Pattern, Key, Value); + +process_file_lines([Line|Rest], SeenLines, Section, Pattern, Key, Value) -> + process_file_lines(Rest, [Line|SeenLines], Section, Pattern, Key, Value); + +process_file_lines([], SeenLines, Section, _Pattern, Key, Value) -> + % Section wasn't found. Append it with the option here. + [Key ++ " = " ++ Value, Section, "" | strip_empty_lines(SeenLines)]. + + +process_section_lines([Line|Rest], SeenLines, Pattern, Key, Value) -> + case re:run(Line, Pattern, [{capture, all_but_first}]) of + nomatch -> % Found nothing interesting. Move on. + process_section_lines(Rest, [Line|SeenLines], Pattern, Key, Value); + {match, []} -> % Found another section. Append the option here. + lists:reverse(Rest) ++ + [Line, "", Key ++ " = " ++ Value | strip_empty_lines(SeenLines)]; + {match, _} -> % Found the option itself. Replace it. + lists:reverse(Rest) ++ [Key ++ " = " ++ Value | SeenLines] + end; + +process_section_lines([], SeenLines, _Pattern, Key, Value) -> + % Found end of file within the section. Append the option here. + [Key ++ " = " ++ Value | strip_empty_lines(SeenLines)]. + + +reverse_and_add_newline([Line|Rest], Content) -> + reverse_and_add_newline(Rest, [Line, "\n", Content]); + +reverse_and_add_newline([], Content) -> + Content. + + +strip_empty_lines(["" | Rest]) -> + strip_empty_lines(Rest); + +strip_empty_lines(All) -> + All. |