Added: Capture method

Fixed: libraries failed to load when not using TLuaLibrary.All

Lua.Wrapper.pas

@@ -245,6 +245,7 @@ type
     procedure SetAutoOpenLibraries(const Value: TLuaLibraries); virtual;
   protected
     procedure CheckState; virtual;
+    procedure CheckIsFunction; virtual;
     procedure AfterLoad; virtual;
 
     function GetRegisteredFunctionCookie: Integer; virtual;
@@ -262,16 +263,17 @@ type
     procedure LoadFromFile(const AFileName: string; AAutoRun: Boolean = True; const AChunkName: string = ''); virtual;
     procedure LoadFromScript(AScript: TLuaScript; AOwnership: TStreamOwnership = soReference; AAutoRun: Boolean = True; const AChunkName: string = ''); virtual;
 
-    function GetGlobalVariable(const AName: string): ILuaVariable;
-    procedure SetGlobalVariable(const AName: string; AVariable: TLuaImplicitVariable);
-    procedure RegisterFunction(const AName: string; AFunction: TLuaCFunction);
+    function GetGlobalVariable(const AName: string): ILuaVariable; virtual;
+    procedure SetGlobalVariable(const AName: string; AVariable: TLuaImplicitVariable); virtual;
+    procedure RegisterFunction(const AName: string; AFunction: TLuaCFunction); virtual;
 
     procedure OpenLibraries(ALibraries: TLuaLibraries); virtual;
 
-    { Run or GetByteCode should only be called right after one of the
+    { These methods should only be called right after one of the
       LoadFrom methods, which must have AutoRun set to False. }
     procedure Run; virtual;
     procedure GetByteCode(AStream: TStream; APop: Boolean = False); virtual;
+    procedure Capture(const AName: string); virtual;
 
     function Call(const AFunctionName: string): ILuaReadParameters; overload; virtual;
     function Call(const AFunctionName: string; AParameters: array of const): ILuaReadParameters; overload; virtual;
@@ -1178,42 +1180,41 @@ begin
   else
   begin
     if TLuaLibrary.Base in ALibraries then
-      luaopen_base(State);
+      luaL_requiref(State, 'base', luaopen_base, 1);
 
     if TLuaLibrary.Coroutine in ALibraries then
-      luaopen_coroutine(State);
+      luaL_requiref(State, 'coroutine', luaopen_coroutine, 1);
 
     if TLuaLibrary.Table in ALibraries then
-      luaopen_table(State);
+      luaL_requiref(State, 'table', luaopen_table, 1);
 
     if TLuaLibrary.IO in ALibraries then
-      luaopen_io(State);
+      luaL_requiref(State, 'io', luaopen_io, 1);
 
     if TLuaLibrary.OS in ALibraries then
-      luaopen_os(State);
+      luaL_requiref(State, 'os', luaopen_os, 1);
 
     if TLuaLibrary.StringLib in ALibraries then
-      luaopen_string(State);
+      luaL_requiref(State, 'string', luaopen_string, 1);
 
     if TLuaLibrary.Bit32 in ALibraries then
-      luaopen_bit32(State);
+      luaL_requiref(State, 'bit32', luaopen_bit32, 1);
 
     if TLuaLibrary.Math in ALibraries then
-      luaopen_math(State);
+      luaL_requiref(State, 'math', luaopen_math, 1);
 
     if TLuaLibrary.Debug in ALibraries then
-      luaopen_debug(State);
+      luaL_requiref(State, 'debug', luaopen_debug, 1);
 
     if TLuaLibrary.Package in ALibraries then
-      luaopen_package(State);
+      luaL_requiref(State, 'package', luaopen_package, 1);
   end;
 end;
 
 
 procedure TLua.Run;
 begin
-  if not lua_isfunction(State, -1) then
-    raise ELuaNoFunctionException.Create('No function on top of the stack, use the LoadFrom methods first');
+  CheckIsFunction;
 
   if lua_pcall(State, 0, 0, 0) <> 0 then
     TLuaHelpers.RaiseLastLuaError(State);
@@ -1225,9 +1226,9 @@ end;
 procedure TLua.GetByteCode(AStream: TStream; APop: Boolean);
 var
   returnCode: Integer;
+
 begin
-  if not lua_isfunction(State, -1) then
-    raise ELuaNoFunctionException.Create('No function on top of the stack, use the LoadFrom methods first');
+  CheckIsFunction;
 
   try
     returnCode := lua_dump(State, LuaWrapperWriter, @AStream);
@@ -1240,6 +1241,42 @@ begin
 end;
 
 
+procedure TLua.Capture(const AName: string);
+var
+  name: PAnsiChar;
+
+begin
+  CheckIsFunction;
+
+  // Create a new table to serve as the environment
+  lua_newtable(State);
+
+  // Set the global AName to the new table
+  lua_pushvalue(State, -1);
+  name := TLuaHelpers.AllocLuaString(AName);
+  try
+    lua_setglobal(State, name);
+  finally
+    TLuaHelpers.FreeLuaString(name);
+  end;
+
+  // Set the global environment as the table's metatable index, so calls to
+  // global functions and variables still work
+  lua_newtable(State);
+  TLuaHelpers.PushString(State, '__index');
+  lua_pushglobaltable(State);
+  lua_settable(State, -3);
+
+  lua_setmetatable(State, -2);
+
+  // Set the new table as the environment (upvalue at index 1)
+  lua_setupvalue(State, -2, 1);
+
+  if lua_pcall(State, 0, 0, 0) <> 0 then
+    TLuaHelpers.RaiseLastLuaError(State);
+end;
+
+
 function TLua.Call(const AFunctionName: string): ILuaReadParameters;
 begin
   Result := Call(AFunctionName, nil);
@@ -1283,6 +1320,13 @@ begin
 end;
 
 
+procedure TLua.CheckIsFunction;
+begin
+  if not lua_isfunction(State, -1) then
+    raise ELuaNoFunctionException.Create('No function on top of the stack, use the LoadFrom methods first');
+end;
+
+
 procedure TLua.AfterLoad;
 var
   cookie: Integer;

Lua.pas

@@ -394,6 +394,8 @@ var
 
   { open all previous libraries }
   luaL_openlibs: procedure(L: lua_State); cdecl;
+  luaL_requiref: procedure(L: lua_State; modname: PAnsiChar; openf: lua_CFunction; glb: Integer); cdecl;
+
 
 
 type
@@ -582,6 +584,7 @@ begin
   Load(@luaopen_package, 'luaopen_package');
 
   Load(@luaL_openlibs, 'luaL_openlibs');
+  Load(@luaL_requiref, 'luaL_requiref');
 
   Load(@luaL_setfuncs, 'luaL_setfuncs');
 end;

UnitTests/source/TestWrapper.pas

@@ -25,6 +25,7 @@ type
     procedure LoadAndRunFromString;
     procedure LoadAndRunFromStream;
     procedure LoadMultiple;
+    procedure LoadMultipleSharedVariable;
     procedure ChunkNameInException;
 
     procedure Input;
@@ -45,6 +46,8 @@ type
 
     procedure VariableFunction;
     procedure ByteCode;
+    procedure Capture;
+    procedure DenyRequire;
   end;
 
 
@@ -65,6 +68,7 @@ begin
   FPrinted := TStringBuilder.Create;
 
   FLua := TLua.Create;
+  FLua.AutoOpenLibraries := [StringLib];
   FLua.RegisterFunction('print',
     procedure(AContext: ILuaContext)
     begin
@@ -112,6 +116,14 @@ begin
 end;
 
 
+procedure TTestWrapper.LoadMultipleSharedVariable;
+begin
+  Lua.LoadFromString('message = "Hello world!"', True, 'Script1');
+  Lua.LoadFromString('print(message)', True, 'Script2');
+
+  CheckEquals('Hello world!', Printed.ToString);
+end;
+
 procedure TTestWrapper.Input;
 begin
   Lua.SetGlobalVariable('thingy', 'world');
@@ -377,6 +389,41 @@ begin
 end;
 
 
+procedure TTestWrapper.Capture;
+begin
+  // Capture is a convenience method which puts a script's variables and
+  // functions in a global table variable. Useful for example when
+  // implementing a sandboxed API.
+  Lua.LoadFromString('message = "Hello world!"'#13#10 +
+                     'function outputMessage()'#13#10 +
+                     '  print(message)'#13#10 +
+                     'end', False, 'Script1');
+  Lua.Capture('Captured');
+
+  Lua.LoadFromString('print(Captured.message)'#13#10 +
+                     'Captured.message = "Goodbye world!"'#13#10 +
+                     'Captured.outputMessage()', True, 'Script2');
+
+  CheckEquals('Hello world!Goodbye world!', Printed.ToString);
+end;
+
+
+procedure TTestWrapper.DenyRequire;
+begin
+  try
+    // This should fail, since we're not loading the Package library which
+    // adds the require function that can be considered a security risk.
+    Lua.LoadFromString('require("Test")');
+    Fail('ELuaException expected');
+  except
+    on E:Exception do
+    begin
+      CheckIs(E, ELuaException);
+    end;
+  end;
+end;
+
+
 initialization
   RegisterTest(TTestWrapper.Suite);