wikimedia/mediawiki-extensions-Wikibase

--[[
    Registers and defines functions to access Wikibase through the Scribunto extension
    Provides Lua setupInterface

    @since 0.4

    @license GNU GPL v2+
    @author Jens Ohlig < jens.ohlig@wikimedia.de >
    @author Marius Hoch < hoo@online.de >
    @author Bene* < benestar.wikimedia@gmail.com >
]]

local wikibase = {}
local util = require 'libraryUtil'
local checkType = util.checkType
local checkTypeMulti = util.checkTypeMulti

-- Get a cache data structure to use with addToCache and getFromCache
-- with a given maximum size.
--
-- @param maxCacheSize
local function initCache( maxCacheSize )
    return {
        data = {},
        order = {},
        size = 0,
        maxCacheSize = maxCacheSize,
    }
end

-- Cache a given value (can also be false, in case it doesn't exist).
--
-- @param cache
-- @param key
-- @param value
local function addToCache( cache, key, value )
    if cache.size == cache.maxCacheSize then
        local toRemove = table.remove( cache.order, cache.maxCacheSize )
        cache.data[ toRemove ] = nil
    else
        cache.size = cache.size + 1
    end

    table.insert( cache.order, 1, key )
    cache.data[ key ] = value
end

-- Retrieve a value from a cache. Will return nil in case of a cache miss.
--
-- @param cache
-- @param key
local function getFromCache( cache, key )
    if cache.data[ key ] ~= nil then
        for cacheOrderId, cacheOrderKey in pairs( cache.order ) do
            if cacheOrderKey == key then
                table.remove( cache.order, cacheOrderId )
                break
            end
        end
        table.insert( cache.order, 1, key )
    end

    return cache.data[ key ]
end

-- 15 slot cache for entities
local entityCache = initCache( 15 )

-- 50 slot cache for statements
local statementCache = initCache( 50 )

function wikibase.setupInterface( settings )
    local php = mw_interface
    mw_interface = nil
    local counter = 0

    -- Caching variable for the entity id string belonging to the current page (nil if page is not linked to an entity)
    local pageEntityId = false

    -- Get the entity id of the connected item, if id is nil. Cached.
    local function getIdOfConnectedItemIfNil( id )
        if id == nil then
            return wikibase.getEntityIdForCurrentPage()
        end

        return id
    end

    -- Get the mw.wikibase.entity object for a given id. Cached.
    local function getEntityObject( id )
        local entity = getFromCache( entityCache, id )

        if entity == nil then
            entity = php.getEntity( id )

            if id ~= wikibase.getEntityIdForCurrentPage() then
                -- Accessing an arbitrary entity is supposed to increment the expensive function count
                php.incrementExpensiveFunctionCount()
            end

            if type( entity ) ~= 'table' then
                entity = false
            end

            addToCache( entityCache, id, entity )
        end

        if type( entity ) ~= 'table' then
            return nil
        end

        local entityModule = require( php.getEntityModuleName( id ) )

        -- Use a deep clone here, so that people can't modify the cached entity
        return entityModule.create( mw.clone( entity ) )
    end

    local function incrementStatsKey( key )
        -- Per T360891#9664129: We only take a sample here, thus only every nth function call actually gets tracked.
        -- The offset we use here is randomly generated in PHP and injected.
        local counterWithOffset = counter + settings.trackLuaFunctionCallsCounterOffset
        local divisor = math.ceil( 1 / settings.trackLuaFunctionCallsSampleRate - 0.5 )

        if counterWithOffset % divisor == 0 then
            php.incrementStatsKey( key )
        end

        counter = counter + 1
    end

    -- Get the entity id for the current page. Cached.
    -- Nil if not linked to an entity.
    function wikibase.getEntityIdForCurrentPage()
        incrementStatsKey( 'wikibase.client.scribunto.wikibase.getEntityIdForCurrentPage.call' )

        if pageEntityId == false then
            pageEntityId = php.getEntityId( tostring( mw.title.getCurrentTitle().prefixedText ) )
        end

        return pageEntityId
    end

    -- Takes a page title string either in the local wiki or another wiki on the same cluster
    -- specified by the global site identifier, and returns the item ID connected via a sitelink, if
    -- one exists. Returns nil if there's no linked item.
    --
    -- @param {string} pageTitle
    -- @param {string} [globalSiteId]
    function wikibase.getEntityIdForTitle( pageTitle, globalSiteId )
        incrementStatsKey( 'wikibase.client.scribunto.wikibase.getEntityIdForTitle.call' )

        checkType( 'getEntityIdForTitle', 1, pageTitle, 'string' )
        checkTypeMulti( 'getEntityIdForTitle', 2, globalSiteId, { 'string', 'nil' } )

        return php.getEntityId( pageTitle, globalSiteId )
    end

    -- Get the mw.wikibase.entity object for the current page or for the
    -- specified id.
    --
    -- @param {string} [id]
    function wikibase.getEntity( id )
        incrementStatsKey( 'wikibase.client.scribunto.wikibase.getEntity.call' )

        checkTypeMulti( 'getEntity', 1, id, { 'string', 'nil' } )

        id = getIdOfConnectedItemIfNil( id )

        if id == nil then
            return nil
        end

        if not settings.allowArbitraryDataAccess and id ~= wikibase.getEntityIdForCurrentPage() then
            error( 'Access to arbitrary entities has been disabled.', 2 )
        end

        return getEntityObject( id )
    end

    -- getEntityObject is an alias for getEntity as these used to be different.
    wikibase.getEntityObject = wikibase.getEntity

    -- @param {string} entityId
    -- @param {string} propertyId
    -- @param {string} funcName for error logging
    -- @param {string} rank Which statements to include. Either "best" or "all".
    local function getEntityStatements( entityId, propertyId, funcName, rank )
        incrementStatsKey( 'wikibase.client.scribunto.wikibase.getEntityStatements.call' )

        if not settings.allowArbitraryDataAccess and entityId ~= wikibase.getEntityIdForCurrentPage() then
            error( 'Access to arbitrary entities has been disabled.', 2 )
        end

        checkType( funcName, 1, entityId, 'string' )
        checkType( funcName, 2, propertyId, 'string' )

        local cacheKey = entityId .. '-' .. propertyId .. '-' .. rank
        local statements = getFromCache( statementCache, cacheKey )
        if statements == nil then
            incrementStatsKey( 'wikibase.client.scribunto.wikibase.getEntityStatements.cache_miss' )

            statements = php.getEntityStatements( entityId, propertyId, rank )
            addToCache( statementCache, cacheKey, statements )
        end

        if statements and statements[propertyId] then
            -- Use a clone here, so that users can't modify the cached statement
            return mw.clone( statements[propertyId] )
        end

        return {}
    end

    -- Returns a table with the "best" statements matching the given property ID on the given entity
    -- ID. The definition of "best" is that the function will return "preferred" statements, if
    -- there are any, otherwise "normal" ranked statements. It will never return "deprecated"
    -- statements. This is what you usually want when surfacing values to an ordinary reader.
    --
    -- @param {string} entityId
    -- @param {string} propertyId
    function wikibase.getBestStatements( entityId, propertyId )
        return getEntityStatements( entityId, propertyId, 'getBestStatements', 'best' )
    end

    -- Returns a table with all statements (including all ranks, even "deprecated") matching the
    -- given property ID on the given entity ID.
    --
    -- @param {string} entityId
    -- @param {string} propertyId
    function wikibase.getAllStatements( entityId, propertyId )
        return getEntityStatements( entityId, propertyId, 'getAllStatements', 'all' )
    end

    -- Get the URL for the given entity id, if specified, or of the
    -- connected entity, if exists.
    --
    -- @param {string} [id]
    function wikibase.getEntityUrl( id )
        incrementStatsKey( 'wikibase.client.scribunto.wikibase.getEntityUrl.call' )

        checkTypeMulti( 'getEntityUrl', 1, id, { 'string', 'nil' } )

        id = getIdOfConnectedItemIfNil( id )

        if id == nil then
            return nil
        end

        return php.getEntityUrl( id )
    end

    -- Get the label, label language for the given entity id, if specified,
    -- or of the connected entity, if exists.
    --
    -- @param {string} [id]
    function wikibase.getLabelWithLang( id )
        incrementStatsKey( 'wikibase.client.scribunto.wikibase.getLabelWithLang.call' )

        checkTypeMulti( 'getLabelWithLang', 1, id, { 'string', 'nil' } )

        id = getIdOfConnectedItemIfNil( id )

        if id == nil then
            return nil, nil
        end

        return php.getLabel( id )
    end

    -- Like wikibase.getLabelWithLang, but only returns the plain label.
    --
    -- @param {string} [id]
    function wikibase.getLabel( id )
        checkTypeMulti( 'getLabel', 1, id, { 'string', 'nil' } )
        local label = wikibase.getLabelWithLang( id )

        return label
    end

    -- Legacy alias for getLabel
    wikibase.label = wikibase.getLabel

    -- Get the label in languageCode for the given entity id.
    --
    -- @param {string} id
    -- @param {string} languageCode
    function wikibase.getLabelByLang( id, languageCode )
        incrementStatsKey( 'wikibase.client.scribunto.wikibase.getLabelByLang.call' )

        checkType( 'getLabelByLang', 1, id, 'string' )
        checkType( 'getLabelByLang', 2, languageCode, 'string' )

        return php.getLabelByLanguage( id, languageCode )
    end

    -- Get the description in languageCode for the given entity id.
    --
    -- @param {string} id
    -- @param {string} languageCode
    function wikibase.getDescriptionByLang( id, languageCode )
        incrementStatsKey( 'wikibase.client.scribunto.wikibase.getDescriptionByLang.call' )

        checkType( 'getDescriptionByLang', 1, id, 'string' )
        checkType( 'getDescriptionByLang', 2, languageCode, 'string' )

        return php.getDescriptionByLanguage( id, languageCode )
    end

    -- Get the description, description language for the given entity id, if specified,
    -- or of the connected entity, if exists.
    --
    -- @param {string} [id]
    function wikibase.getDescriptionWithLang( id )
        incrementStatsKey( 'wikibase.client.scribunto.wikibase.getDescriptionWithLang.call' )

        checkTypeMulti( 'getDescriptionWithLang', 1, id, { 'string', 'nil' } )

        id = getIdOfConnectedItemIfNil( id )

        if id == nil then
            return nil, nil
        end

        return php.getDescription( id )
    end

    -- Like wikibase.getDescriptionWithLang, but only returns the plain description.
    --
    -- @param {string} [id]
    function wikibase.getDescription( id )
        checkTypeMulti( 'getDescription', 1, id, { 'string', 'nil' } )
        local description = wikibase.getDescriptionWithLang( id )

        return description
    end

    -- Legacy alias for getDescription
    wikibase.description = wikibase.getDescription

    -- Get the local sitelink title for the given entity id.
    --
    -- @param {string} itemId
    -- @param {string} [globalSiteId]
    function wikibase.getSitelink( itemId, globalSiteId )
        incrementStatsKey( 'wikibase.client.scribunto.wikibase.getSitelink.call' )

        checkType( 'getSitelink', 1, itemId, 'string' )
        checkTypeMulti( 'getSitelink', 2, globalSiteId, { 'string', 'nil' } )

        return php.getSiteLinkPageName( itemId, globalSiteId )
    end

    -- Legacy alias for getSitelink
    wikibase.sitelink = wikibase.getSitelink

    -- Is this a valid (parseable) entity id?
    --
    -- @param {string} entityIdSerialization
    function wikibase.isValidEntityId( entityIdSerialization )
        incrementStatsKey( 'wikibase.client.scribunto.wikibase.isValidEntityId.call' )

        checkType( 'isValidEntityId', 1, entityIdSerialization, 'string' )

        return php.isValidEntityId( entityIdSerialization )
    end

    -- Does the entity in question exist?
    --
    -- @param {string} entityId
    function wikibase.entityExists( entityId )
        incrementStatsKey( 'wikibase.client.scribunto.wikibase.entityExists.call' )

        checkType( 'entityExists', 1, entityId, 'string' )

        if not settings.allowArbitraryDataAccess and entityId ~= wikibase.getEntityIdForCurrentPage() then
            error( 'Access to arbitrary entities has been disabled.', 2 )
        end

        return php.entityExists( entityId )
    end

    -- Return a list of badges from an item for a certain site (or the local wiki).
    --
    -- @param {string} itemId
    -- @param {string} [globalSiteId]
    function wikibase.getBadges( itemId, globalSiteId )
        incrementStatsKey( 'wikibase.client.scribunto.wikibase.getBadges.call' )

        checkType( 'getBadges', 1, itemId, 'string' )
        checkTypeMulti( 'getBadges', 2, globalSiteId, { 'string', 'nil' } )

        if itemId ~= wikibase.getEntityIdForCurrentPage() then
            if not settings.allowArbitraryDataAccess then
                error( 'Access to arbitrary entities has been disabled.', 2 )
            end
            -- Currently the whole entity needs to be loaded (PHP side), thus making this expensive.
            php.incrementExpensiveFunctionCount()
        end

        return php.getBadges( itemId, globalSiteId )
    end

    -- Render a Snak value from its serialization as wikitext escaped plain text.
    --
    -- @param {table} snakSerialization
    function wikibase.renderSnak( snakSerialization )
        incrementStatsKey( 'wikibase.client.scribunto.wikibase.renderSnak.call' )

        checkType( 'renderSnak', 1, snakSerialization, 'table' )

        return php.renderSnak( snakSerialization )
    end

    -- Render a Snak value from its serialization as rich wikitext.
    --
    -- @param {table} snakSerialization
    function wikibase.formatValue( snakSerialization )
        incrementStatsKey( 'wikibase.client.scribunto.wikibase.formatValue.call' )

        checkType( 'formatValue', 1, snakSerialization, 'table' )

        return php.formatValue( snakSerialization )
    end

    -- Render a list of Snak values from their serialization as wikitext escaped plain text.
    --
    -- @param {table} snaksSerialization
    function wikibase.renderSnaks( snaksSerialization )
        incrementStatsKey( 'wikibase.client.scribunto.wikibase.renderSnaks.call' )

        checkType( 'renderSnaks', 1, snaksSerialization, 'table' )

        return php.renderSnaks( snaksSerialization )
    end

    -- Render a list of Snak values from their serialization as rich wikitext.
    --
    -- @param {table} snaksSerialization
    function wikibase.formatValues( snaksSerialization )
        incrementStatsKey( 'wikibase.client.scribunto.wikibase.formatValues.call' )

        checkType( 'formatValues', 1, snaksSerialization, 'table' )

        return php.formatValues( snaksSerialization )
    end

    -- Returns a property id for the given label or id
    --
    -- @param {string} propertyLabelOrId
    function wikibase.resolvePropertyId( propertyLabelOrId )
        incrementStatsKey( 'wikibase.client.scribunto.wikibase.resolvePropertyId.call' )

        checkType( 'resolvePropertyId', 1, propertyLabelOrId, 'string' )

        return php.resolvePropertyId( propertyLabelOrId )
    end

    -- Returns a table of the given property IDs ordered
    --
    -- @param {table} propertyIds
    function wikibase.orderProperties( propertyIds )
        incrementStatsKey( 'wikibase.client.scribunto.wikibase.orderProperties.call' )

        checkType( 'orderProperties', 1, propertyIds, 'table' )
        return php.orderProperties( propertyIds )
    end

    -- Returns an ordered table of serialized property IDs
    function wikibase.getPropertyOrder()
        incrementStatsKey( 'wikibase.client.scribunto.wikibase.getPropertyOrder.call' )

        return php.getPropertyOrder()
    end

    -- Get the closest referenced entity (out of toIds), from a given entity.
    --
    -- @param {string} fromEntityId
    -- @param {string} propertyId
    -- @param {table} toIds
    function wikibase.getReferencedEntityId( fromEntityId, propertyId, toIds )
        incrementStatsKey( 'wikibase.client.scribunto.wikibase.getReferencedEntityId.call' )

        checkType( 'getReferencedEntityId', 1, fromEntityId, 'string' )
        checkType( 'getReferencedEntityId', 2, propertyId, 'string' )
        checkType( 'getReferencedEntityId', 3, toIds, 'table' )

        -- Check the type of all toId values, Scribunto has no function for this yet (T196048)
        for i, toId in ipairs( toIds ) do
            if type( toId ) ~= 'string' then
                error(
                    'toIds value at index ' .. i .. ' must be string, ' .. type( toId ) .. ' given.',
                    1
                )
            end
        end

        if not settings.allowArbitraryDataAccess then
            error( 'Access to arbitrary entities has been disabled.', 2 )
        end

        return php.getReferencedEntityId( fromEntityId, propertyId, toIds )
    end

    -- Returns the current site's global id
    function wikibase.getGlobalSiteId()
        incrementStatsKey( 'wikibase.client.scribunto.wikibase.getGlobalSiteId.call' )
        return settings.siteGlobalID
    end

    mw = mw or {}
    mw.wikibase = wikibase
    package.loaded['mw.wikibase'] = wikibase
    wikibase.setupInterface = nil
end

return wikibase