Implement require() using package.loaders, etc. add preload_loader, lua_loader, and java_loader.

src/core/org/luaj/lib/BaseLib.java

@@ -397,8 +397,8 @@ public class BaseLib extends LFunction {
 		}
 	}
 
-	// return true if laoded, false if error put onto the stack
-	private static boolean loadis(LuaState vm, InputStream is, String chunkname ) {
+	// return true if loaded, false if error put onto the stack
+	static boolean loadis(LuaState vm, InputStream is, String chunkname ) {
 		try {
 			vm.resettop();
 			if ( 0 != vm.load(is, chunkname) ) {

src/core/org/luaj/lib/PackageLib.java

@@ -23,6 +23,7 @@ package org.luaj.lib;
 
 import java.io.InputStream;
 import java.io.PrintStream;
+import java.util.Vector;
 
 import org.luaj.vm.CallInfo;
 import org.luaj.vm.LBoolean;
@@ -33,10 +34,13 @@ import org.luaj.vm.LTable;
 import org.luaj.vm.LValue;
 import org.luaj.vm.Lua;
 import org.luaj.vm.LuaState;
+import org.luaj.vm.Platform;
 
 
 public class PackageLib extends LFunction {
 
+	public static final String DEFAULT_LUA_PATH = "?.luac;?.lua";
+	
 	public static InputStream STDIN = null;
 	public static PrintStream STDOUT = System.out;
 	public static LTable      LOADED = new LTable();
@@ -47,6 +51,11 @@ public class PackageLib extends LFunction {
 	private static final LString _DOT = new LString(".");
 	private static final LString _EMPTY = new LString("");
 	private static final LString __INDEX = new LString("__index");
+	private static final LString _LOADERS = new LString("loaders");
+	private static final LString _PRELOAD = new LString("preload");
+	private static final LString _PATH = new LString("path");
+	private static final LValue  _SENTINEL = _EMPTY;
+	private static final LString _LUA_PATH = new LString(DEFAULT_LUA_PATH);
 	
 	private static final String[] NAMES = {
 		"package",
@@ -54,6 +63,9 @@ public class PackageLib extends LFunction {
 		"require",
 		"loadlib",
 		"seeall",
+		"preload_loader",
+		"lua_loader",
+		"java_loader",
 	};
 	
 	private static final int INSTALL        = 0;
@@ -61,16 +73,27 @@ public class PackageLib extends LFunction {
 	private static final int REQUIRE        = 2;
 	private static final int LOADLIB        = 3;
 	private static final int SEEALL         = 4;
+	private static final int PRELOAD_LOADER = 5;
+	private static final int LUA_LOADER     = 6;
+	private static final int JAVA_LOADER    = 7;
 	
+	// all functions in package share this environment 
+	private static LTable pckg;
 	
 	public static void install( LTable globals ) {
-		for ( int i=1; i<LOADLIB; i++ )
+		for ( int i=1; i<=REQUIRE; i++ )
 			globals.put( NAMES[i], new PackageLib(i) );
-		LTable pckg = new LTable();
-		for ( int i=LOADLIB; i<NAMES.length; i++ )
+		pckg = new LTable();
+		for ( int i=LOADLIB; i<=SEEALL; i++ )
 			pckg.put( NAMES[i], new PackageLib(i) );
-		globals.put( "package", pckg );
 		pckg.put( "loaded", LOADED );
+		pckg.put( _PRELOAD, new LTable() );
+		LTable loaders = new LTable(3,0);
+		for ( int i=PRELOAD_LOADER; i<=JAVA_LOADER; i++ )
+			loaders.luaInsertPos(0, new PackageLib(i) );
+		pckg.put( "loaders", loaders );
+		pckg.put( _PATH, _LUA_PATH );
+		globals.put( "package", pckg );
 	}
 	
 	private final int id;
@@ -108,6 +131,18 @@ public class PackageLib extends LFunction {
 			vm.resettop();
 			break;
 		}
+		case PRELOAD_LOADER: {
+			loader_preload(vm);
+			break;
+		}
+		case LUA_LOADER: {
+			loader_Lua(vm);
+			break;
+		}
+		case JAVA_LOADER: {
+			loader_Java(vm);
+			break;
+		}
 		default:
 			luaUnsupportedOperation();
 		}
@@ -236,29 +271,141 @@ public class PackageLib extends LFunction {
 	 * If there is any error loading or running the module, or if it cannot find any loader for 
 	 * the module, then require signals an error.
 	 */	
-	public static void require( LuaState vm ) {
-		LString modname = vm.tolstring(2);
-		if ( LOADED.containsKey(modname) ) {
+	public void require( LuaState vm ) {
+		LString name = vm.tolstring(2);
+		LValue loaded = LOADED.get(name);
+		if ( loaded.toJavaBoolean() ) {
+			if ( loaded == _SENTINEL )
+				vm.error("loop or previous error loading module '"+name+"'");
 			vm.resettop();
-			vm.pushlvalue( LOADED.get(modname) );
+			vm.pushlvalue( loaded );
+			return;
 		}
-		else {
-			String s = modname.toJavaString();
-			if ( ! BaseLib.loadfile(vm, s+".luac") && ! BaseLib.loadfile(vm, s+".lua") )
-				vm.error( "not found: "+s );
-			else if ( 0 == vm.pcall(0, 1, 0) ) {
-				LValue result = vm.topointer( -1 ); 
-				if ( result != LNil.NIL )
-					LOADED.put(modname, result);
-				else if ( ! LOADED.containsKey(modname) )
-					LOADED.put(modname, result = LBoolean.TRUE);
+		vm.settop(0);
+		
+		/* else must load it; iterate over available loaders */
+		pckg.luaGetTable(vm, pckg, _LOADERS);
+		if ( ! vm.istable(1) )
+			vm.error( "'package.loaders' must be a table" );
+		Vector v = new Vector();
+		for ( int i=1; true; i++ ) {
+		    vm.rawgeti(1, i);
+		    if ( vm.isnil(-1) ) {
+		    	vm.error( "module '"+name+"' not found: "+v );
+		    }
+		    /* call loader with module name as argument */
+		    vm.pushlstring(name);
+		    vm.call(1, 1);
+		    if ( vm.isfunction(-1) )
+		    	break;  /* module loaded successfully */
+		    if ( vm.isstring(-1) )  /* loader returned error message? */
+		    	v.addElement(vm.tolstring(-1));  /* accumulate it */
+	    	vm.pop(1);
+		}
+
+		// load the module using the loader
+		LOADED.luaSetTable(vm, LOADED, name, _SENTINEL);
+		vm.pushlstring( name );  /* pass name as argument to module */
+		vm.call( 1, 1 ); /* run loaded module */
+		if ( ! vm.isnil(-1) ) /* non-nil return? */
+			LOADED.luaSetTable(vm, LOADED, name, vm.topointer(-1) ); /* _LOADED[name] = returned value */
 		vm.resettop();
-				vm.pushlvalue( result );
-			}
+		LOADED.luaGetTable(vm, LOADED, name);		
+		if ( vm.topointer(-1) == _SENTINEL ) {   /* module did not set a value? */
+			LOADED.luaSetTable(vm, LOADED, name, LBoolean.TRUE ); /* _LOADED[name] = true */
+			vm.resettop();
+			vm.pushboolean(true);
 		}
 	}
 
 	public static void loadlib( LuaState vm ) {
 		vm.error( "loadlib not implemented" );
 	}
+
+
+	private void loader_preload( LuaState vm ) {
+		LString name = vm.tolstring(2);
+		pckg.luaGetTable(vm, pckg, _PRELOAD);
+		if ( ! vm.istable(-1) )
+			vm.error("package.preload '"+name+"' must be a table");
+		LTable preload = vm.totable(-1); 
+		preload.luaGetTable(vm, preload, name);
+		if ( vm.isnil(-1) )
+			vm.pushstring("\n\tno field package.preload['"+name+"']");
+		vm.insert(1);
+		vm.settop(1);
+	}
+
+	private void loader_Lua( LuaState vm ) {
+		String name = vm.tostring(2);
+		InputStream is = findfile( vm, name, _PATH );
+		if ( is != null ) {
+			String filename = vm.tostring(-1);
+			if ( ! BaseLib.loadis(vm, is, filename) )
+				loaderror( vm, filename );
+		}
+		vm.insert(1);
+		vm.settop(1);
+	}
+
+	private void loader_Java( LuaState vm ) {
+		String name = vm.tostring(2);
+		Class c = null;
+		LValue v = null;
+		try {
+			c = Class.forName(name);
+			v = (LValue) c.newInstance();
+			vm.pushlvalue( v );
+		} catch ( ClassNotFoundException  cnfe ) {
+			vm.pushstring("\n\tno class '"+name+"'" );
+		} catch ( Exception e ) {
+			vm.pushstring("\n\tjava load failed on '"+name+"', "+e );
+		}
+		vm.insert(1);
+		vm.settop(1);		
+	}
+
+	private InputStream findfile(LuaState vm, String name, LString pname) {
+		Platform p = Platform.getInstance();
+		pckg.luaGetTable(vm, pckg, pname);
+		if ( ! vm.isstring(-1) )
+			vm.error("package."+pname+" must be a string");
+		String path = vm.tostring(-1);
+		int te = -1;
+		int n = path.length();
+		StringBuffer sb = null;
+		while ( te < n ) {
+			
+			// find next template
+			int tb = te+1;
+			te = path.indexOf(';',tb);
+			if ( te < 0 )
+				te = path.length();
+			String template = path.substring(tb,te);
+
+			// create filename
+			int ques = template.indexOf('?');
+			String filename = (ques<0? template: template.substring(0,ques)+name+template.substring(ques+1));
+			
+			// try opening the file
+			InputStream is = p.openFile(filename);
+			if ( is != null ) {
+				vm.pushstring(filename);
+				return is;
+			}
+			
+			// report error
+			if ( sb == null )
+				sb = new StringBuffer();
+			sb.append( "\n\tno file '"+filename+"'");
+		}
+		
+		// not found, push error on stack and return
+		vm.pushstring(sb.toString());
+		return null;
+	}
+
+	private static void loaderror(LuaState vm, String filename) {
+		vm.error( "error loading module '"+vm.tostring(1)+"' from file '"+filename+"':\n\t"+vm.tostring(-1) );
+	}
 }

src/core/org/luaj/vm/LClosure.java

@@ -24,9 +24,10 @@ package org.luaj.vm;
 
 
 public class LClosure extends LFunction {
-	public LTable env;
 	public LPrototype p;
 	public UpVal[] upVals;
+	public LTable env;
+	
 	
 	/**
 	 * @deprecated construct with environment instead 
@@ -63,5 +64,4 @@ public class LClosure extends LFunction {
 		this.env = t;
 		return 1;
 	}
-
 }

src/core/org/luaj/vm/LThread.java

@@ -40,10 +40,10 @@ public class LThread extends LValue implements Runnable {
 	
 	private int status = STATUS_SUSPENDED;
 	
-	private LuaState threadVm;
-	private Thread thread;
+	LuaState threadVm;
+	Thread thread;
 	
-	private static LThread running;
+	static LThread running;
 	
 	
 	public LThread(LClosure c) {

src/core/org/luaj/vm/LuaState.java

@@ -96,6 +96,7 @@ public class LuaState extends Lua {
     protected Stack upvals = new Stack();
 	protected LFunction panic;
     
+	public static LTable DEFAULT_GLOBALS;
     public LTable _G;
 
     // main debug hook, overridden by DebugStackState
@@ -120,11 +121,16 @@ public class LuaState extends Lua {
 	 * @deprecated As of version 0.10, replaced by {@link #newState()}
 	 */
 	public LuaState() {
-		_G = new LTable();
+		_G = DEFAULT_GLOBALS = new LTable();
 		_G.put("_G", _G);
 	}
 
-	public LuaState(LTable globals) {
+	/** 
+	 * Create a LuaState with a specific global environment. Used by LThread.
+	 * 
+	 * @param globals the LTable to use as globals for this LuaState  
+	 */
+	LuaState(LTable globals) {
 		_G = globals;
 	}
 
@@ -1364,11 +1370,9 @@ public class LuaState extends Lua {
 	 * href="#2.8">&sect;2.8</a>).
 	 * 
 	 */
-	public void getfield(int index, String k) {
+	public void getfield(int index, LString k) {
 		LTable t = totable(index);
-		// TODO: what if this triggers metatable ops
-		// pushlvalue( t.luaGetTable(this, t, new LString(k)) );
-		t.luaGetTable(this, t, new LString(k));
+		t.luaGetTable(this, t, k);
 	}
 	
 	/**
@@ -2039,10 +2043,10 @@ public class LuaState extends Lua {
 	 * trigger a metamethod for the "newindex" event (see <a
 	 * href="#2.8">&sect;2.8</a>).
 	 */
-	public void setfield(int index, String k) {
+	public void setfield(int index, LString k) {
 		LTable t = totable(index);
 		LValue v = poplvalue();
-		t.luaSetTable(this, t, new LString(k), v);
+		t.luaSetTable(this, t, k, v);
 	}
 
 	/**
@@ -2570,4 +2574,21 @@ public class LuaState extends Lua {
 		return topointer(index).toJavaBoxedLong();
 	}
 	
+	/**
+	 * Get the current environment. 
+	 * 
+	 * @return LTable the current environment
+	 */
+//	public LTable curr_env() {
+//		LuaState vm = (LThread.running!=null? 
+//				LThread.running.threadVm: 
+//				this);
+//		for ( int i=vm.cc; i>=0; i-- ) {
+//			LClosure c = vm.calls[cc].closure;
+//			if ( c != null ) 
+//				return c.env;
+//		}
+//		return _G;
+//	}
+	
 }

src/sample/org/luaj/sample/LuaRunner.java

@@ -54,6 +54,8 @@ public class LuaRunner {
 				
 		// load the file
 		InputStream is = LuaRunner.class.getResourceAsStream( script );
+		if ( is == null )
+			throw new java.io.FileNotFoundException( "not found: "+script );
 		LPrototype p = LoadState.undump(state, is, script);
 		
 		// create closure and execute

src/test/java/org/luaj/vm/LuaJTest.java

@@ -90,6 +90,10 @@ public class LuaJTest extends TestCase {
 		runTest( "pcalls" );
 	}
 	
+	public void testRequire() throws IOException, InterruptedException {
+		runTest( "require" );
+	}
+	
 	public void testSelect() throws IOException, InterruptedException {
 		runTest( "select" );
 	}

src/test/res/require.lua

@@ -1,5 +1,6 @@
 -- unit tests for require() function
 local ids = {}
+local ti = table.insert
 local function id(obj)
 	if not obj or type(obj) == 'number' or type(obj) == 'string' then
 		return obj
@@ -8,12 +9,13 @@ local function id(obj)
 	if v then
 		return v
 	end
-	table.insert(ids,obj)
+	ti(ids,obj)
 	ids[obj] = type(obj)..'.'..tostring(#ids)
 	return ids[obj]
 end 
 
 -- tests on require
+package.path='?.lua;src/test/res/?.lua'
 function f( name )
 	print( module( 'testmod', package.seeall ) )
 	print( 'before', id(sample), id(bogus), id(_G[name]) );
@@ -33,7 +35,7 @@ f('bogus')
 print( 'main', id(sample), id(bogus), id(custom) );
 
 -- custom loader chain
-for i=1,4 do
+for i=1,3 do
 	print( i,id(package.loaders[i]) )
 end
 function loader1( ... )