mirror of
https://gerrit.wikimedia.org/r/mediawiki/extensions/Scribunto
synced 2024-11-30 11:04:17 +00:00
40b8bd2caa
Clean up trailing whitespace from all of our code, and add comments indicating that apparently unused variables are ScopedCallbacks. Change-Id: I8e5997797cc7b1c64c5351ec112a18f30edc8fef
654 lines
17 KiB
Lua
654 lines
17 KiB
Lua
MWServer = {}
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--- Create a new MWServer object
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function MWServer:new( interpreterId )
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interpreterId = tonumber( interpreterId )
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if not interpreterId then
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error( "bad argument #1 to 'MWServer:new' (must be a number or convertible to a number)", 2 )
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end
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obj = {
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interpreterId = interpreterId,
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nextChunkId = 1,
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chunks = {},
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xchunks = {},
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protectedFunctions = {},
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protectedEnvironments = {},
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baseEnv = {}
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}
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setmetatable( obj, self )
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self.__index = self
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obj:init()
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return obj
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end
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--- Initialise a new MWServer object
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function MWServer:init()
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self.baseEnv = self:newEnvironment()
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for funcName, func in pairs( self ) do
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if type(func) == 'function' then
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self.protectedFunctions[func] = true
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end
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end
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self.protectedEnvironments[_G] = true
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end
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--- Serve requests until exit is requested
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function MWServer:execute()
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self:dispatch( nil )
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self:debug( 'MWServer:execute: returning' )
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end
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-- Convert a multiple-return-value or a ... into a count and a table
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function MWServer:listToCountAndTable( ... )
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return select( '#', ... ), { ... }
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end
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--- Call a PHP function
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-- Raise an error if the PHP handler requests it. May return any number
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-- of values.
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--
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-- @param id The function ID, specified by a registerLibrary message
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-- @param nargs Count of function arguments
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-- @param args The function arguments
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-- @return The return values from the PHP function
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function MWServer:call( id, nargs, args )
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local result = self:dispatch( {
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op = 'call',
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id = id,
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nargs = nargs,
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args = args
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} )
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if result.op == 'return' then
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return unpack( result.values, 1, result.nvalues )
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elseif result.op == 'error' then
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-- Raise an error in the actual user code that called the function
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-- The level is 3 since our immediate caller is a closure
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error( result.value, 3 )
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else
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self:internalError( 'MWServer:call: unexpected result op' )
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end
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end
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--- Handle a "call" message from PHP. Call the relevant function.
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--
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-- @param message The message from PHP
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-- @return A response message to send back to PHP
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function MWServer:handleCall( message )
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if not self.chunks[message.id] then
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return {
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op = 'error',
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value = 'function id ' .. message.id .. ' does not exist'
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}
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end
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local n, result = self:listToCountAndTable( xpcall(
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function ()
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return self.chunks[message.id]( unpack( message.args, 1, message.nargs ) )
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end,
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function ( err )
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return MWServer:attachTrace( err )
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end
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) )
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if result[1] then
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-- table.remove( result, 1 ) renumbers from 2 to #result. But #result
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-- is not necessarily "right" if result contains nils.
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result = { unpack( result, 2, n ) }
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return {
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op = 'return',
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nvalues = n - 1,
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values = result
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}
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else
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if result[2].value and result[2].trace then
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return {
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op = 'error',
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value = result[2].value,
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trace = result[2].trace,
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}
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else
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return {
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op = 'error',
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value = result[2]
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}
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end
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end
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end
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--- The xpcall() error handler for handleCall(). Modifies the error object
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-- to include a structured backtrace
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--
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-- @param err The error object
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-- @return The new error object
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function MWServer:attachTrace( err )
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return {
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value = err,
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trace = self:getStructuredTrace( 2 )
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}
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end
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--- Handle a "loadString" message from PHP.
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-- Load the function and return a chunk ID.
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--
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-- @param message The message from PHP
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-- @return A response message to send back to PHP
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function MWServer:handleLoadString( message )
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if string.find( message.text, '\27Lua', 1, true ) then
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return {
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op = 'error',
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value = 'cannot load code with a Lua binary chunk marker escape sequence in it'
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}
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end
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local chunk, errorMsg = loadstring( message.text, message.chunkName )
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if chunk then
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setfenv( chunk, self.baseEnv )
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local id = self:addChunk( chunk )
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return {
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op = 'return',
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nvalues = 1,
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values = {id}
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}
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else
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return {
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op = 'error',
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value = errorMsg
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}
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end
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end
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--- Add a function value to the list of tracked chunks and return its associated ID.
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-- Adding a chunk allows it to be referred to in messages from PHP.
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--
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-- @param chunk The function value
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-- @return The chunk ID
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function MWServer:addChunk( chunk )
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local id = self.nextChunkId
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self.nextChunkId = id + 1
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self.chunks[id] = chunk
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self.xchunks[chunk] = id
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return id
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end
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--- Handle a "cleanupChunks" message from PHP.
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-- Remove any chunks no longer referenced by PHP code.
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--
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-- @param message The message from PHP
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-- @return A response message to send back to PHP
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function MWServer:handleCleanupChunks( message )
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for id, chunk in pairs( self.chunks ) do
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if not message.ids[id] then
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self.chunks[id] = nil
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self.xchunks[chunk] = nil
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end
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end
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return {
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op = 'return',
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nvalues = 0,
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values = {}
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}
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end
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--- Handle a "registerLibrary" message from PHP.
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-- Add the relevant functions to the base environment.
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--
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-- @param message The message from PHP
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-- @return The response message
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function MWServer:handleRegisterLibrary( message )
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local startPos = 1
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local component
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if not self.baseEnv[message.name] then
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self.baseEnv[message.name] = {}
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end
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local t = self.baseEnv[message.name]
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for name, id in pairs( message.functions ) do
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t[name] = function( ... )
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return self:call( id, self:listToCountAndTable( ... ) )
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end
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-- Protect the function against setfenv()
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self.protectedFunctions[t[name]] = true
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end
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return {
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op = 'return',
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nvalues = 0,
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values = {}
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}
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end
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--- Handle a "wrapPhpFunction" message from PHP.
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-- Create an anonymous function
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--
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-- @param message The message from PHP
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-- @return The response message
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function MWServer:handleWrapPhpFunction( message )
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local id = message.id
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local func = function( ... )
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return self:call( id, self:listToCountAndTable( ... ) )
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end
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-- Protect the function against setfenv()
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self.protectedFunctions[func] = true
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return {
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op = 'return',
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nvalues = 1,
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values = { func }
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}
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end
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--- Handle a "getStatus" message from PHP
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--
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-- @param message The request message
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-- @return The response message
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function MWServer:handleGetStatus( message )
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local nullRet = {
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op = 'return',
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nvalues = 0,
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values = {}
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}
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local file = io.open( '/proc/self/stat' )
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if not file then
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return nullRet
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end
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local s = file:read('*a')
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file:close()
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local t = {}
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for token in string.gmatch(s, '[^ ]+') do
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t[#t + 1] = token
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end
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if #t < 22 then
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return nullRet
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end
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return {
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op = 'return',
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nvalues = 1,
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values = {{
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pid = tonumber(t[1]),
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time = tonumber(t[14]) + tonumber(t[15]) + tonumber(t[16]) + tonumber(t[17]),
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vsize = tonumber(t[23]),
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}}
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}
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end
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--- The main request/response loop
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--
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-- Send a request message and return its matching reply message. Handle any
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-- intervening requests (i.e. re-entrant calls) by dispatching them to the
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-- relevant handler function.
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--
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-- The request message may optionally be omitted, to listen for request messages
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-- without first sending a request of its own. Such a dispatch() call will
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-- continue running until termination is requested by PHP. Typically, PHP does
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-- this with a SIGTERM signal.
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--
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-- @param msgToPhp The message to send to PHP. Optional.
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-- @return The matching response message
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function MWServer:dispatch( msgToPhp )
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if msgToPhp then
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self:sendMessage( msgToPhp )
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end
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while true do
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local msgFromPhp = self:receiveMessage()
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local msgToPhp
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local op = msgFromPhp.op
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if op == 'return' or op == 'error' then
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return msgFromPhp
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elseif op == 'call' then
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msgToPhp = self:handleCall( msgFromPhp )
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self:sendMessage( msgToPhp )
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elseif op == 'loadString' then
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msgToPhp = self:handleLoadString( msgFromPhp )
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self:sendMessage( msgToPhp )
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elseif op == 'registerLibrary' then
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msgToPhp = self:handleRegisterLibrary( msgFromPhp )
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self:sendMessage( msgToPhp )
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elseif op == 'wrapPhpFunction' then
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msgToPhp = self:handleWrapPhpFunction( msgFromPhp )
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self:sendMessage( msgToPhp )
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elseif op == 'cleanupChunks' then
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msgToPhp = self:handleCleanupChunks( msgFromPhp )
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self:sendMessage( msgToPhp )
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elseif op == 'getStatus' then
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msgToPhp = self:handleGetStatus( msgFromPhp )
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self:sendMessage( msgToPhp )
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elseif op == 'quit' then
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self:debug( 'MWServer:dispatch: quit message received' )
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os.exit(0)
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else
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self:internalError( "Invalid message operation" )
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end
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end
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end
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--- Write a message to the debug output stream.
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-- Some day this may be configurable, currently it just unconditionally writes
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-- the message to stderr. The PHP host will redirect those errors to /dev/null
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-- by default, but it can be configured to send them to a file.
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--
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-- @param s The message
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function MWServer:debug( s )
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if ( type(s) == 'string' ) then
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io.stderr:write( s .. '\n' )
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else
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io.stderr:write( self:serialize( s ) .. '\n' )
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end
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end
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--- Raise an internal error
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-- Write a message to stderr and then exit with a failure status. This should
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-- be called for errors which cannot be allowed to be caught with pcall().
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--
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-- This must be used for protocol errors, or indeed any error from a context
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-- where a dispatch() call lies between the error source and a possible pcall()
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-- handler. If dispatch() were terminated by a regular error() call, the
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-- resulting protocol violation could lead to a deadlock.
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--
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-- @param msg The error message
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function MWServer:internalError( msg )
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io.stderr:write( debug.traceback( msg ) .. '\n' )
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os.exit( 1 )
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end
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--- Raise an I/O error
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-- Helper function for errors from the io and file modules, which may optionally
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-- return an informative error message as their second return value.
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function MWServer:ioError( header, info )
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if type( info) == 'string' then
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self:internalError( header .. ': ' .. info )
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else
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self:internalError( header )
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end
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end
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--- Send a message to PHP
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-- @param msg The message table
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function MWServer:sendMessage( msg )
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if not msg.op then
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self:internalError( "MWServer:sendMessage: invalid message", 2 )
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end
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self:debug('TX ==> ' .. msg.op)
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local encMsg = self:encodeMessage( msg )
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local success, errorMsg = io.stdout:write( encMsg )
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if not success then
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self:ioError( 'Write error', errorMsg )
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end
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io.stdout:flush()
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end
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--- Wait for a message from PHP and then decode and return it as a table
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-- @return The received message
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function MWServer:receiveMessage()
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-- Read the header
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local header, errorMsg = io.stdin:read( 16 )
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if header == nil and errorMsg == nil then
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-- End of file on stdin, exit gracefully
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os.exit(0)
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end
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if not header or #header ~= 16 then
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self:ioError( 'Read error', errorMsg )
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end
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local length = self:decodeHeader( header )
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-- Read the body
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local body, errorMsg = io.stdin:read( length )
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if not body then
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self:ioError( 'Read error', errorMsg )
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end
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if #body ~= length then
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self:ioError( 'Read error', errorMsg )
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end
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-- Unserialize it
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msg = self:unserialize( body )
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self:debug('RX <== ' .. msg.op)
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if msg.op == 'error' then
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self:debug( 'Error: ' .. tostring( msg.value ) )
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end
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return msg
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end
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--- Encode a message for sending to PHP
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function MWServer:encodeMessage( message )
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local serialized = self:serialize( message )
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local length = #serialized
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local check = length * 2 - 1
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return string.format( '%08x%08x', length, check ) .. serialized
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end
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-- Faster to create the table once than for each call to MWServer:serialize()
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local serialize_replacements = {
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['\r'] = '\\r',
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['\n'] = '\\n',
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['\\'] = '\\\\',
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}
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--- Convert a value to a string suitable for passing to PHP's unserialize().
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-- Note that the following replacements must be performed before calling
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-- unserialize:
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-- "\\r" => "\r"
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-- "\\n" => "\n"
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-- "\\\\" => "\\"
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--
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-- @param var The value.
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function MWServer:serialize( var )
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local done = {}
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local int_min = -2147483648
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local int_max = 2147483647
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local function isInteger( var )
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return type(var) == 'number'
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and math.floor( var ) == var
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and var >= int_min
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and var <= int_max
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end
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local function recursiveEncode( var, level )
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local t = type( var )
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if t == 'nil' then
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return 'N;'
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elseif t == 'number' then
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if isInteger(var) then
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return 'i:' .. var .. ';'
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elseif var < math.huge and var > -math.huge then
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return 'd:' .. var .. ';'
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elseif var == math.huge then
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return 'd:INF;'
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elseif var == -math.huge then
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return 'd:-INF;'
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else
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return 'd:NAN;'
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end
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elseif t == 'string' then
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return 's:' .. string.len( var ) .. ':"' .. var .. '";'
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elseif t == 'boolean' then
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if var then
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return 'b:1;'
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else
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return 'b:0;'
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end
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elseif t == 'table' then
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if done[var] then
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error("Cannot pass circular reference to PHP")
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end
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done[var] = true
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local buf = { '' }
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local numElements = 0
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for key, value in pairs(var) do
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local t = type( key )
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if t == 'number' or t == 'string' then
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if (isInteger(key)) then
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buf[#buf + 1] = 'i:' .. key .. ';'
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else
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buf[#buf + 1] = recursiveEncode( tostring( key ), level + 1 )
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end
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else
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error("Cannot use " .. type( key ) .. " as an array key when passing data from Lua to PHP");
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end
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buf[#buf + 1] = recursiveEncode( value, level + 1 )
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numElements = numElements + 1
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end
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buf[1] = 'a:' .. numElements .. ':{'
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buf[#buf + 1] = '}'
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return table.concat(buf)
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elseif t == 'function' then
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local id
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if self.xchunks[var] then
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id = self.xchunks[var]
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else
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id = self:addChunk(var)
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end
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return 'O:42:"Scribunto_LuaStandaloneInterpreterFunction":2:{s:13:"interpreterId";i:' ..
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self.interpreterId .. ';s:2:"id";i:' .. id .. ';}'
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elseif t == 'thread' then
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error("Cannot pass thread to PHP")
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elseif t == 'userdata' then
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error("Cannot pass userdata to PHP")
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else
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error("Cannot pass unrecognised type to PHP")
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end
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end
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return recursiveEncode( var, 0 ):gsub( '[\r\n\\]', serialize_replacements )
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end
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--- Convert a Lua expression string to its corresponding value.
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-- Convert any references of the form chunk[id] to the corresponding function
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-- values.
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function MWServer:unserialize( text )
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local func = loadstring( 'return ' .. text )
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if not func then
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self:internalError( "MWServer:unserialize: invalid chunk" )
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end
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-- Don't waste JIT cache space by storing every message in it
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if jit then
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jit.off( func )
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end
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setfenv( func, { chunks = self.chunks } )
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return func()
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end
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--- Decode a message header.
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-- @param header The header string
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-- @return The body length
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function MWServer:decodeHeader( header )
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local length = string.sub( header, 1, 8 )
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local check = string.sub( header, 9, 16 )
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if not string.match( length, '^%x+$' ) or not string.match( check, '^%x+$' ) then
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self:internalError( "Error decoding message header: " .. length .. '/' .. check )
|
|
end
|
|
length = tonumber( length, 16 )
|
|
check = tonumber( check, 16 )
|
|
if length * 2 - 1 ~= check then
|
|
self:internalError( "Error decoding message header" )
|
|
end
|
|
return length
|
|
end
|
|
|
|
--- Get a traceback similar to the one from debug.traceback(), but as a table
|
|
-- rather than formatted as a string
|
|
--
|
|
-- @param The level to start at: 1 for the function that called getStructuredTrace()
|
|
-- @return A table with the backtrace information
|
|
function MWServer:getStructuredTrace( level )
|
|
level = level + 1
|
|
local trace = {}
|
|
while true do
|
|
local rawInfo = debug.getinfo( level, 'nSl' )
|
|
if rawInfo == nil then
|
|
break
|
|
end
|
|
local info = {}
|
|
for i, key in ipairs({'short_src', 'what', 'currentline', 'name', 'namewhat', 'linedefined'}) do
|
|
info[key] = rawInfo[key]
|
|
end
|
|
if string.match( info['short_src'], '/MWServer.lua$' ) then
|
|
info['short_src'] = 'MWServer.lua'
|
|
end
|
|
if string.match( rawInfo['short_src'], '/mw_main.lua$' ) then
|
|
info['short_src'] = 'mw_main.lua'
|
|
end
|
|
table.insert( trace, info )
|
|
level = level + 1
|
|
end
|
|
return trace
|
|
end
|
|
|
|
--- Create a table to be used as a restricted environment, based on the current
|
|
-- global environment.
|
|
--
|
|
-- @return The environment table
|
|
function MWServer:newEnvironment()
|
|
local allowedGlobals = {
|
|
-- base
|
|
"assert",
|
|
"error",
|
|
"getmetatable",
|
|
"ipairs",
|
|
"next",
|
|
"pairs",
|
|
"pcall",
|
|
"rawequal",
|
|
"rawget",
|
|
"rawset",
|
|
"select",
|
|
"setmetatable",
|
|
"tonumber",
|
|
"type",
|
|
"unpack",
|
|
"xpcall",
|
|
"_VERSION",
|
|
-- libs
|
|
"table",
|
|
"math"
|
|
}
|
|
|
|
local env = {}
|
|
for i = 1, #allowedGlobals do
|
|
env[allowedGlobals[i]] = mw.clone( _G[allowedGlobals[i]] )
|
|
end
|
|
|
|
-- Cloning 'string' doesn't work right, because strings still use the old
|
|
-- 'string' as the metatable. So just copy it.
|
|
env.string = string
|
|
|
|
env._G = env
|
|
env.tostring = function( val )
|
|
return self:tostring( val )
|
|
end
|
|
env.string.dump = nil
|
|
env.setfenv, env.getfenv = mw.makeProtectedEnvFuncs(
|
|
self.protectedEnvironments, self.protectedFunctions )
|
|
env.debug = {
|
|
traceback = debug.traceback
|
|
}
|
|
env.os = {
|
|
date = os.date,
|
|
difftime = os.difftime,
|
|
time = os.time,
|
|
clock = os.clock
|
|
}
|
|
return env
|
|
end
|
|
|
|
--- An implementation of tostring() which does not expose pointers.
|
|
function MWServer:tostring(val)
|
|
local mt = getmetatable( val )
|
|
if mt and mt.__tostring then
|
|
return mt.__tostring(val)
|
|
end
|
|
local typeName = type(val)
|
|
local nonPointerTypes = {number = true, string = true, boolean = true, ['nil'] = true}
|
|
if nonPointerTypes[typeName] then
|
|
return tostring(val)
|
|
else
|
|
return typeName
|
|
end
|
|
end
|
|
|
|
return MWServer
|