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--[[--
A pure Lua implementation of a gettext subset.
Example:
local _ = require("gettext") -- @{gettext.gettext|gettext}()
local C_ = _.pgettext -- @{pgettext}()
local N_ = _.ngettext -- @{ngettext}()
local NC_ = _.npgettext -- @{npgettext}()
local T = require("ffi/util").template -- @{ffi.util.template}()
-- The most common use case with regular @{gettext.gettext|gettext}().
local simple_string = _("item")
-- A more complex example. The correct plural form will be automatically
-- selected by @{ngettext}() based on the number.
local numbered_string = T(N_("1 item", "%1 items", num_items), num_items)
It's required to pass along the number twice, because @{ngettext}() doesn't do anything with placeholders.
See @{ffi.util.template}() for more information about the template function.
--]]
local isAndroid, android = pcall(require, "android")
local logger = require("logger")
local GetText = {
context = {},
translation = {},
current_lang = "C",
dirname = "l10n",
textdomain = "koreader",
plural_default = "n != 1",
}
local GetText_mt = {
__index = {}
}
-- wrapUntranslated() will be overriden by bidi.lua when UI language is RTL,
-- to wrap untranslated english strings as LTR-isolated segments.
-- It should do nothing when the UI language is LTR.
GetText.wrapUntranslated_nowrap = function(text) return text end
GetText.wrapUntranslated = GetText.wrapUntranslated_nowrap
-- Note: this won't be possible if we switch from our Lua GetText to
-- GetText through FFI (but hopefully, RTL languages will be fully
-- translated by then).
--[[--
Returns a translation.
@function gettext
@string msgid
@treturn string translation
@usage
local _ = require("gettext")
local translation = _("A meaningful message.")
--]]
function GetText_mt.__call(gettext, msgid)
return gettext.translation[msgid] or gettext.wrapUntranslated(msgid)
end
local function c_escape(what)
if what == "\n" then return ""
elseif what == "a" then return "\a"
elseif what == "b" then return "\b"
elseif what == "f" then return "\f"
elseif what == "n" then return "\n"
elseif what == "r" then return "\r"
elseif what == "t" then return "\t"
elseif what == "v" then return "\v"
elseif what == "0" then return "\0" -- shouldn't happen, though
else
return what
end
end
--- Converts C logical operators to Lua.
local function logicalCtoLua(logical_str)
logical_str = logical_str:gsub("&&", "and")
logical_str = logical_str:gsub("!=", "~=")
logical_str = logical_str:gsub("||", "or")
return logical_str
end
--- Default getPlural function.
local function getDefaultPlural(n)
if n ~= 1 then
return 1
else
return 0
end
end
--- Generates a proper Lua function out of logical gettext math tests.
local function getPluralFunc(pl_tests, nplurals, plural_default)
-- the return function() stuff is a bit of loadstring trickery
local plural_func_str = "return function(n) if "
if #pl_tests > 1 then
for i = 1, #pl_tests do
local pl_test = pl_tests[i]
pl_test = logicalCtoLua(pl_test)
if i > 1 and not (tonumber(pl_test) ~= nil) then
pl_test = " elseif "..pl_test
end
if tonumber(pl_test) ~= nil then
-- no condition, just a number
pl_test = " else return "..pl_test
end
pl_test = pl_test:gsub("?", " then return")
-- append to plural function
plural_func_str = plural_func_str..pl_test
end
plural_func_str = plural_func_str.." end end"
else
local pl_test = pl_tests[1]
-- Ensure JIT compiled function if we're dealing with one of the many simpler languages.
-- After all, loadstring won't be.
-- Potential workaround: write to file and use require.
if pl_test == plural_default then
return getDefaultPlural
end
-- language with no plural forms
if tonumber(pl_test) ~= nil then
plural_func_str = "return function(n) return "..pl_test.." end"
else
pl_test = logicalCtoLua(pl_test)
plural_func_str = "return function(n) if "..pl_test.." then return 1 else return 0 end end"
end
end
logger.dbg("gettext: plural function", plural_func_str)
return loadstring(plural_func_str)()
end
local function addTranslation(msgctxt, msgid, msgstr, n)
-- translated string
local unescaped_string = string.gsub(msgstr, "\\(.)", c_escape)
if msgctxt and msgctxt ~= "" then
if not GetText.context[msgctxt] then
GetText.context[msgctxt] = {}
end
if n then
if not GetText.context[msgctxt][msgid] then
GetText.context[msgctxt][msgid] = {}
end
GetText.context[msgctxt][msgid][n] = unescaped_string ~= "" and unescaped_string or nil
else
GetText.context[msgctxt][msgid] = unescaped_string ~= "" and unescaped_string or nil
end
else
if n then
if not GetText.translation[msgid] then
GetText.translation[msgid] = {}
end
GetText.translation[msgid][n] = unescaped_string ~= "" and unescaped_string or nil
else
GetText.translation[msgid] = unescaped_string ~= "" and unescaped_string or nil
end
end
end
-- for PO file syntax, see
-- https://www.gnu.org/software/gettext/manual/html_node/PO-Files.html
-- we only implement a sane subset for now
function GetText_mt.__index.changeLang(new_lang)
GetText.context = {}
GetText.translation = {}
GetText.current_lang = "C"
-- the "C" locale disables localization altogether
-- can be various things such as `en_US` or `en_US:en`
if new_lang == "C" or new_lang == nil or new_lang == ""
or new_lang:match("^en_US") == "en_US" then return end
-- strip encoding suffix in locale like "zh_CN.utf8"
new_lang = new_lang:sub(1, new_lang:find(".%."))
local file = GetText.dirname .. "/" .. new_lang .. "/" .. GetText.textdomain .. ".po"
local po = io.open(file, "r")
if not po then
logger.dbg("cannot open translation file:", file)
return false
end
local data = {}
local fuzzy = false
local headers
local what = nil
while true do
local line = po:read("*l")
if line == nil or line == "" then
if data.msgid and data.msgid_plural and data["msgstr[0]"] then
for k, v in pairs(data) do
local n = tonumber(k:match("msgstr%[([0-9]+)%]"))
local msgstr = v
if n and msgstr then
addTranslation(data.msgctxt, data.msgid, msgstr, n)
end
end
elseif data.msgid and data.msgstr and data.msgstr ~= "" then
-- header
if not headers and data.msgid == "" then
headers = data.msgstr
local plural_forms = data.msgstr:match("Plural%-Forms: (.*)")
local nplurals = plural_forms:match("nplurals=([0-9]+);") or 2
local plurals = plural_forms:match("plural=%((.*)%);")
-- Hardcoded workaround for Hebrew which has 4 plural forms.
if plurals == "n == 1) ? 0 : ((n == 2) ? 1 : ((n > 10 && n % 10 == 0) ? 2 : 3)" then
plurals = "n == 1 ? 0 : (n == 2) ? 1 : (n > 10 && n % 10 == 0) ? 2 : 3"
end
-- Hardcoded workaround for Romanian which has 3 plural forms.
if plurals == "n == 1) ? 0 : ((n == 0 || n != 1 && n % 100 >= 1 && n % 100 <= 19) ? 1 : 2" then
plurals = "n == 1 ? 0 : (n == 0 || n != 1 && n % 100 >= 1 && n % 100 <= 19) ? 1 : 2"
end
if not plurals then
-- Some languages (e.g., Arabic) may not use parentheses.
-- However, the following more inclusive match is more likely
-- to accidentally include junk and seldom relevant.
-- We might also be dealing with a language without plurals.
-- That would look like `plural=0`.
plurals = plural_forms:match("plural=(.*);")
end
if plurals:find("[^n!=%%<>&:%(%)|?0-9 ]") then
-- we don't trust this input, go with default instead
plurals = GetText.plural_default
end
local pl_tests = {}
for pl_test in plurals:gmatch("[^:]+") do
table.insert(pl_tests, pl_test)
end
GetText.getPlural = getPluralFunc(pl_tests, nplurals, GetText.plural_default)
if not GetText.getPlural then
GetText.getPlural = getDefaultPlural
end
end
addTranslation(data.msgctxt, data.msgid, data.msgstr)
end
-- stop at EOF:
if line == nil then break end
data = {}
what = nil
else
-- comment
if not line:match("^#") then
-- new data item (msgid, msgstr, ...
local w, s = line:match("^%s*([%a_%[%]0-9]+)%s+\"(.*)\"%s*$")
if w then
what = w
else
-- string continuation
s = line:match("^%s*\"(.*)\"%s*$")
end
if what and s and not fuzzy then
-- unescape \n or msgid won't match
s = s:gsub("\\n", "\n")
-- unescape " or msgid won't match
s = s:gsub('\\"', '"')
-- unescape \\ or msgid won't match
s = s:gsub("\\\\", "\\")
data[what] = (data[what] or "") .. s
else
-- Don't save this fuzzy string and unset fuzzy for the next one.
fuzzy = false
end
elseif line:match("#, fuzzy") then
fuzzy = true
end
end
end
GetText.current_lang = new_lang
end
GetText_mt.__index.getPlural = getDefaultPlural
--[[--
Returns a plural form.
Many languages have more forms than just singular and plural. This function
abstracts the complexity away. The translation can contain as many
pluralizations as it requires.
See [gettext plural forms](https://www.gnu.org/software/gettext/manual/html_node/Plural-forms.html)
and [translating plural forms](https://www.gnu.org/software/gettext/manual/html_node/Translating-plural-forms.html)
for more information.
It's required to pass along the number twice, because @{ngettext}() doesn't do anything with placeholders.
See @{ffi.util.template}() for more information about the template function.
@function ngettext
@string msgid
@string msgid_plural
@int n
@treturn string translation
@usage
local _ = require("gettext")
local N_ = _.ngettext
local T = require("ffi/util").template
local items_string = T(N_("1 item", "%1 items", num_items), num_items)
--]]
function GetText_mt.__index.ngettext(msgid, msgid_plural, n)
local plural = GetText.getPlural(n)
if plural == 0 then
return GetText.translation[msgid] and GetText.translation[msgid][plural] or GetText.wrapUntranslated(msgid)
else
return GetText.translation[msgid] and GetText.translation[msgid][plural] or GetText.wrapUntranslated(msgid_plural)
end
end
--[[--
Returns a context-disambiguated plural form.
This is the logical combination between @{ngettext}() and @{pgettext}().
Please refer there for more information.
@function npgettext
@string msgctxt
@string msgid
@string msgid_plural
@int n
@treturn string translation
@usage
local _ = require("gettext")
local NC_ = _.npgettext
local T = require("ffi/util").template
local statistics_items_string = T(NC_("Statistics", "1 item", "%1 items", num_items), num_items)
local books_items_string = T(NC_("Books", "1 item", "%1 items", num_items), num_items)
--]]
function GetText_mt.__index.npgettext(msgctxt, msgid, msgid_plural, n)
local plural = GetText.getPlural(n)
if plural == 0 then
return GetText.context[msgctxt] and GetText.context[msgctxt][msgid] and GetText.context[msgctxt][msgid][plural] or GetText.wrapUntranslated(msgid)
else
return GetText.context[msgctxt] and GetText.context[msgctxt][msgid] and GetText.context[msgctxt][msgid][plural] or GetText.wrapUntranslated(msgid_plural)
end
end
--[[--
Returns a context-disambiguated translation.
The same string might occur multiple times, but require a different translation based on context.
An example within KOReader is **Pages** meaning *page styles* (within the context of style tweaks)
and **Pages** meaning *number of pages*.
We generally don't apply context unless a conflict is known. This is only likely to occur with
short strings, of which of course there are many.
See [gettext contexts](https://www.gnu.org/software/gettext/manual/html_node/Contexts.html) for more information.
@function pgettext
@string msgctxt
@string msgid
@treturn string translation
@usage
local _ = require("gettext")
local C_ = _.pgettext
local copy_file = C_("File", "Copy")
local copy_text = C_("Text", "Copy")
--]]
function GetText_mt.__index.pgettext(msgctxt, msgid)
return GetText.context[msgctxt] and GetText.context[msgctxt][msgid] or GetText.wrapUntranslated(msgid)
end
setmetatable(GetText, GetText_mt)
if os.getenv("LANGUAGE") then
GetText.changeLang(os.getenv("LANGUAGE"))
elseif os.getenv("LC_ALL") then
GetText.changeLang(os.getenv("LC_ALL"))
elseif os.getenv("LC_MESSAGES") then
GetText.changeLang(os.getenv("LC_MESSAGES"))
elseif os.getenv("LANG") then
GetText.changeLang(os.getenv("LANG"))
end
if isAndroid then
local ffi = require("ffi")
local buf = ffi.new("char[?]", 16)
android.lib.AConfiguration_getLanguage(android.app.config, buf)
local lang = ffi.string(buf)
android.lib.AConfiguration_getCountry(android.app.config, buf)
local country = ffi.string(buf)
if lang and country then
GetText.changeLang(lang.."_"..country)
end
end
return GetText