Merge branch 'master' of ssh://git.eclipse.org/gitroot/koneki/org.eclipse.koneki...

[metalua.git] / metalua / loader.lua

diff --git a/metalua/loader.lua b/metalua/loader.lua
new file mode 100644 (file)
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--- /dev/null
+++ b/metalua/loader.lua
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+--------------------------------------------------------------------------------
+-- Copyright (c) 2006-2013 Fabien Fleutot and others.
+--
+-- All rights reserved.
+--
+-- This program and the accompanying materials are made available
+-- under the terms of the Eclipse Public License v1.0 which
+-- accompanies this distribution, and is available at
+-- http://www.eclipse.org/legal/epl-v10.html
+--
+-- This program and the accompanying materials are also made available
+-- under the terms of the MIT public license which accompanies this
+-- distribution, and is available at http://www.lua.org/license.html
+--
+-- Contributors:
+--     Fabien Fleutot - API and implementation
+--
+--------------------------------------------------------------------------------
+
+local M = require "package" -- extend Lua's basic "package" module
+
+M.metalua_extension_prefix = 'metalua.extension.'
+
+-- Initialize package.mpath from package.path
+M.mpath = M.mpath or os.getenv 'LUA_MPATH' or
+    (M.path..";") :gsub("%.(lua[:;])", ".m%1") :sub(1, -2)
+
+M.mcache = M.mcache or os.getenv 'LUA_MCACHE'
+
+----------------------------------------------------------------------
+-- resc(k) returns "%"..k if it's a special regular expression char,
+-- or just k if it's normal.
+----------------------------------------------------------------------
+local regexp_magic = { }
+for k in ("^$()%.[]*+-?") :gmatch "." do regexp_magic[k]="%"..k end
+
+local function resc(k) return regexp_magic[k] or k end
+
+----------------------------------------------------------------------
+-- Take a Lua module name, return the open file and its name,
+-- or <false> and an error message.
+----------------------------------------------------------------------
+function M.findfile(name, path_string)
+   local config_regexp = ("([^\n])\n"):rep(5):sub(1, -2)
+   local dir_sep, path_sep, path_mark, execdir, igmark =
+      M.config :match (config_regexp)
+   name = name:gsub ('%.', dir_sep)
+   local errors = { }
+   local path_pattern = string.format('[^%s]+', resc(path_sep))
+   for path in path_string:gmatch (path_pattern) do
+      --printf('path = %s, rpath_mark=%s, name=%s', path, resc(path_mark), name)
+      local filename = path:gsub (resc (path_mark), name)
+      --printf('filename = %s', filename)
+      local file = io.open (filename, 'r')
+      if file then return file, filename end
+      table.insert(errors, string.format("\tno lua file %q", filename))
+   end
+   return false, '\n'..table.concat(errors, "\n")..'\n'
+end
+
+----------------------------------------------------------------------
+-- Before compiling a metalua source module, try to find and load
+-- a more recent bytecode dump. Requires lfs
+----------------------------------------------------------------------
+local function metalua_cache_loader(name, src_filename, src)
+    local mlc          = require 'metalua.compiler'.new()
+    local lfs          = require 'lfs'
+    local dir_sep      = M.config:sub(1,1)
+    local dst_filename = M.mcache :gsub ('%?', (name:gsub('%.', dir_sep)))
+    local src_a        = lfs.attributes(src_filename)
+    local src_date     = src_a and src_a.modification or 0
+    local dst_a        = lfs.attributes(dst_filename)
+    local dst_date     = dst_a and dst_a.modification or 0
+    local delta        = dst_date - src_date
+    local bytecode, file, msg
+    if delta <= 0 then
+       print "NEED TO RECOMPILE"
+       bytecode = mlc :src_to_bytecode (src, name)
+       for x in dst_filename :gmatch('()'..dir_sep) do
+          lfs.mkdir(dst_filename:sub(1,x))
+       end
+       file, msg = io.open(dst_filename, 'wb')
+       if not file then error(msg) end
+       file :write (bytecode)
+       file :close()
+    else
+       file, msg = io.open(dst_filename, 'rb')
+       if not file then error(msg) end
+       bytecode = file :read '*a'
+       file :close()
+    end
+    return mlc :bytecode_to_function (bytecode)
+end
+
+----------------------------------------------------------------------
+-- Load a metalua source file.
+----------------------------------------------------------------------
+function M.metalua_loader (name)
+   local file, filename_or_msg = M.findfile (name, M.mpath)
+   if not file then return filename_or_msg end
+   local luastring = file:read '*a'
+   file:close()
+   if M.mcache and pcall(require, 'lfs') then
+      return metalua_cache_loader(name, filename_or_msg, luastring)
+   else return require 'metalua.compiler'.new() :src_to_function (luastring, name) end
+end
+
+
+----------------------------------------------------------------------
+-- Placed after lua/luac loader, so precompiled files have
+-- higher precedence.
+----------------------------------------------------------------------
+table.insert(M.loaders, M.metalua_loader)
+
+----------------------------------------------------------------------
+-- Load an extension.
+----------------------------------------------------------------------
+function extension (name, mlp)
+    local complete_name = M.metalua_extension_prefix..name
+    local extend_func = require (complete_name)
+    if not mlp.extensions[complete_name] then
+        local ast =extend_func(mlp)
+        mlp.extensions[complete_name] =extend_func
+        return ast
+     end
+end
+
+return M