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--[[--
This module handles generic settings as well as KOReader's global settings system.
]]
local dump = require("dump")
local ffiutil = require("ffi/util")
local lfs = require("libs/libkoreader-lfs")
local logger = require("logger")
local LuaSettings = {}
function LuaSettings:new(o)
o = o or {}
setmetatable(o, self)
self.__index = self
return o
end
--- Opens a settings file.
function LuaSettings:open(file_path)
local new = {file=file_path}
local ok, stored
-- File being absent and returning an empty table is a use case,
-- so logger.warn() only if there was an existing file
local existing = lfs.attributes(new.file, "mode") == "file"
ok, stored = pcall(dofile, new.file)
if ok and stored then
new.data = stored
else
if existing then logger.warn("Failed reading", new.file, "(probably corrupted).") end
-- Fallback to .old if it exists
ok, stored = pcall(dofile, new.file..".old")
if ok and stored then
if existing then logger.warn("read from backup file", new.file..".old") end
new.data = stored
else
if existing then logger.warn("no usable backup file for", new.file, "to read from") end
new.data = {}
end
end
return setmetatable(new, {__index = LuaSettings})
end
--- @todo DocSettings can return a LuaSettings to use following awesome features.
function LuaSettings:wrap(data)
local new = {data = type(data) == "table" and data or {}}
return setmetatable(new, {__index = LuaSettings})
end
--[[--Reads child settings.
@usage
Settings:saveSetting("key", {
a = "b",
c = true,
d = false,
})
local child = Settings:child("key")
child:readSetting("a")
-- result "b"
]]
function LuaSettings:child(key)
return LuaSettings:wrap(self:readSetting(key))
end
--[[-- Reads a setting, optionally initializing it to a default.
If default is provided, and the key doesn't exist yet, it is initialized to default first.
This ensures both that the defaults are actually set if necessary,
and that the returned reference actually belongs to the LuaSettings object straight away,
without requiring further interaction (e.g., saveSetting) from the caller.
This is mainly useful if the data type you want to retrieve/store is assigned/returned/passed by reference (e.g., a table),
and you never actually break that reference by assigning another one to the same variable, (by e.g., assigning it a new object).
c.f., <https://www.lua.org/manual/5.1/manual.html#2.2>.
@param key The setting's key
@param default Initialization data (Optional)
]]
function LuaSettings:readSetting(key, default)
-- No initialization data: legacy behavior
if not default then
return self.data[key]
end
if not self:has(key) then
self.data[key] = default
end
return self.data[key]
end
--- Saves a setting.
function LuaSettings:saveSetting(key, value)
self.data[key] = value
return self
end
--- Deletes a setting.
function LuaSettings:delSetting(key)
self.data[key] = nil
return self
end
--- Checks if setting exists.
function LuaSettings:has(key)
return self.data[key] ~= nil
end
--- Checks if setting does not exist.
function LuaSettings:hasNot(key)
return self.data[key] == nil
end
--- Checks if setting is `true` (boolean).
function LuaSettings:isTrue(key)
return self.data[key] == true
end
--- Checks if setting is `false` (boolean).
function LuaSettings:isFalse(key)
return self.data[key] == false
end
--- Checks if setting is `nil` or `true`.
function LuaSettings:nilOrTrue(key)
return self:hasNot(key) or self:isTrue(key)
end
--- Checks if setting is `nil` or `false`.
function LuaSettings:nilOrFalse(key)
return self:hasNot(key) or self:isFalse(key)
end
--- Flips `nil` or `true` to `false`, and `false` to `nil`.
--- e.g., a setting that defaults to true.
function LuaSettings:flipNilOrTrue(key)
if self:nilOrTrue(key) then
self:saveSetting(key, false)
else
self:delSetting(key)
end
return self
end
--- Flips `nil` or `false` to `true`, and `true` to `nil`.
--- e.g., a setting that defaults to false.
function LuaSettings:flipNilOrFalse(key)
if self:nilOrFalse(key) then
self:saveSetting(key, true)
else
self:delSetting(key)
end
return self
end
--- Flips a setting between `true` and `nil`.
function LuaSettings:flipTrue(key)
if self:isTrue(key) then
self:delSetting(key)
else
self:saveSetting(key, true)
end
return self
end
--- Flips a setting between `false` and `nil`.
function LuaSettings:flipFalse(key)
if self:isFalse(key) then
self:delSetting(key)
else
self:saveSetting(key, false)
end
return self
end
-- Unconditionally makes a boolean setting `true`.
function LuaSettings:makeTrue(key)
self:saveSetting(key, true)
return self
end
-- Unconditionally makes a boolean setting `false`.
function LuaSettings:makeFalse(key)
self:saveSetting(key, false)
return self
end
--- Toggles a boolean setting
function LuaSettings:toggle(key)
if self:nilOrFalse(key) then
self:saveSetting(key, true)
else
self:saveSetting(key, false)
end
return self
end
-- Initializes settings per extension with default values
function LuaSettings:initializeExtSettings(key, defaults, force_init)
local curr = self:readSetting(key)
if not curr or force_init then
self:saveSetting(key, defaults)
return true
end
return false
end
-- Returns saved setting for given extension
function LuaSettings:getSettingForExt(key, ext)
local saved_settings = self:readSetting(key) or {}
return saved_settings[ext]
end
-- Sets setting for given extension
function LuaSettings:saveSettingForExt(key, value, ext)
local saved_settings = self:readSetting(key) or {}
saved_settings[ext] = value
self:saveSetting(key, saved_settings)
end
--- Adds item to table.
function LuaSettings:addTableItem(key, value)
local settings_table = self:has(key) and self:readSetting(key) or {}
table.insert(settings_table, value)
self:saveSetting(key, settings_table)
return self
end
--- Removes index from table.
function LuaSettings:removeTableItem(key, index)
local settings_table = self:has(key) and self:readSetting(key) or {}
table.remove(settings_table, index)
self:saveSetting(key, settings_table)
return self
end
--- Replaces existing settings with table.
function LuaSettings:reset(table)
self.data = table
return self
end
--- Writes settings to disk.
function LuaSettings:flush()
if not self.file then return end
local directory_updated = false
if lfs.attributes(self.file, "mode") == "file" then
-- As an additional safety measure (to the ffiutil.fsync* calls
-- used below), we only backup the file to .old when it has
-- not been modified in the last 60 seconds. This should ensure
-- in the case the fsync calls are not supported that the OS
-- may have itself sync'ed that file content in the meantime.
local mtime = lfs.attributes(self.file, "modification")
if mtime < os.time() - 60 then
os.rename(self.file, self.file .. ".old")
directory_updated = true -- fsync directory content too below
end
end
local f_out = io.open(self.file, "w")
if f_out ~= nil then
os.setlocale('C', 'numeric')
f_out:write("-- we can read Lua syntax here!\nreturn ")
f_out:write(dump(self.data, nil, true))
f_out:write("\n")
ffiutil.fsyncOpenedFile(f_out) -- force flush to the storage device
f_out:close()
end
if directory_updated then
-- Ensure the file renaming is flushed to storage device
ffiutil.fsyncDirectory(self.file)
end
return self
end
--- Closes settings file.
function LuaSettings:close()
self:flush()
end
--- Purges settings file.
function LuaSettings:purge()
if self.file then
os.remove(self.file)
end
return self
end
return LuaSettings