「モジュール:Tr/loaddata」を編集中

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--
-- =============================================================================
--
-- Module:Tr/loaddata
--
-- Cache management of the translation databases for Module:Tr
--
-- =============================================================================
--
-- Code annotations:
-- This module is documented according to LuaCATS (Lua Comment and Type System).
-- LuaCATS comments are prefixed with three dashes (---) and use Markdown syntax.
-- For a full list of annotations, see the following link:
-- https://luals.github.io/wiki/annotations/
--
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local cache = mw.ext.LuaCache
local trim = mw.text.trim

-- Note:
-- It seems that objects/lists stored via LuaCache have a limit on the number of
-- entities, which is about 8000. Any object/list with more than 8000 entities or
-- with such a large sub-object/sub-list will be truncated. Therefore, we encode
-- the data into a JSON string to get around this problem.

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---Main return object
local p = {}

---Get the cached translation database for the specified language `lang`. Recreate
---the cache if necessary.
---This function should only be called from the `Module:Tr/loaddata-<lang>` modules
---(e.g. `Module:Tr/loaddata-ar`), like so: `return require('Module:Tr/loaddata').load('<lang>')`
---@param lang string Language code
---@return table<string, string> data
p.load = function(lang)
	-- attempt to load the cached data
	local success, result = pcall(function()
		return mw.text.jsonDecode(cache.get('tr__database-' .. lang))
	end)
	if success then
		-- cached data is available, just return it
		return result
	end

	-- cached data is not available, so we need to recreate it

	---Fetch the database. We use `require()` for this and not `mw.loadData()`
	---because the return table of `mw.loadData()` has a metatable and therefore
	---cannot be used with `cache.set()` and `mw.loadData()`.
	---@type table
	local info = require('Module:Tr/db-' .. lang)

	---List of language codes that are "on-wiki", i.e. not on a separate wiki. See
	---[[Template:LangList]].
	---@type { [string]: true }
	info.onWikiLangList = {}
	local langListStr = mw.getCurrentFrame():expandTemplate{ title = 'langList', args = {'onWiki'} }
	-- convert e.g. `"ar, bg, cs, da"` to `{"ar", " bg", " cs", " da"}`, then to
	-- `{["ar"] = true, ["bg"] = true, ["cs"] = true, ["da"] = true}`
	for _, langcode in ipairs(mw.text.split(langListStr, ',')) do
		info.onWikiLangList[trim(langcode)] = true
	end

	---Assemble the database for "reverse" translation (local language to English).
	---@type table<string, string>
	local reversed = {}
	-- add all terms from the `main` table
	for termEnglish, termLocalLanguage in pairs(info.main or {}) do
		reversed[termLocalLanguage] = termEnglish
	end
	-- add all terms from the `pagename` table, potentially overriding the `main`
	-- table where necessary
	for termEnglish, termLocalLanguage in pairs(info.pagename or {}) do
		reversed[termLocalLanguage] = termEnglish
	end
	-- add all manually specified terms, potentially overriding any terms from
	-- `main` and `pagename` tables
	for termLocalLanguage, termEnglish in pairs(info.reversed or {}) do
		reversed[termLocalLanguage] = termEnglish
	end
	-- for on-wiki languages: the translation `<English page>/<lang>` => `<English page>`
	-- is handled by {{pagename2en}}, so there's no need to add that to this database
	info.reversed = reversed

	-- cache the `info` table
	cache.set('tr__database-' .. lang, mw.text.jsonEncode(info))
	return info
end  -- p.load

---Purge the translation database for the specified language `<lang>`. When the
---`load` function is called the next time, the database cache will be forcefully
---recreated.
---This function should only be called from the `purge` function of `Module:Tr`.
---That function can be invoked from wikitext via `{{#invoke:Tr|purge|lang=<lang>}}`,
---which is done on each `Module:Tr/db-<lang>/doc` page. So purging that documentation
---page (or the module page `Module:Tr/db-<lang>` itself) will call this function
---and purge the respective language's translation database cache.
---@param lang string Language code
p.purge = function(lang)
	cache.delete('tr__database-' .. lang)
end  -- p.purge

return p