git.r.bdr.sh - rbdr/pico-engine/blob - LuaScript.cpp

   1 // ---------------------------------------------------------------------------
   2 // FILE NAME            : LuaScript.cpp
   3 // ---------------------------------------------------------------------------
   4 // DESCRIPTION :
   5 //
   6 // Simple debugging routines
   7 //
   8 // ---------------------------------------------------------------------------
   9 // VERSION              : 1.00
  10 // DATE                 : 1-Sep-2005
  11 // AUTHOR               : Richard Shephard
  12 // ---------------------------------------------------------------------------
  13 // LIBRARY INCLUDE FILES
  14 #include <assert.h>
  15 #include "luainc.h"
  16 #include "luascript.h"
  17 #include "luarestorestack.h"
  18 #include "luathis.h"
  19 // ---------------------------------------------------------------------------
  20
  21 #define BEGIN_LUA_CHECK(vm)   lua_State *state = (lua_State *) vm; \
  22                               if (vm.Ok ()) {
  23 #define END_LUA_CHECK         }
  24
  25
  26 //============================================================================
  27 // int LuaCallback
  28 //---------------------------------------------------------------------------
  29 // Lua C-API calling that figures out which object to hand over to
  30 //
  31 // Parameter   Dir      Description
  32 // ---------   ---      -----------
  33 // lua         IN       State variable
  34 //
  35 // Return
  36 // ------
  37 // Number of return varaibles on the stack
  38 //
  39 // Comments
  40 // --------
  41 // This is the function lua calls for each C-Function that is
  42 // registered with lua. At the time of registering the function
  43 // with lua, we make lua record the method "number" so we can
  44 // know what method was actually called. The lua stack is the
  45 // following structure:
  46 // 0: 'this' (table)
  47 // 1 - ...: parameters passed in
  48 //
  49 //============================================================================
  50 static int LuaCallback (lua_State *lua)
  51 {
  52    // Locate the psudo-index for the function number
  53    int iNumberIdx = lua_upvalueindex (1);
  54    int nRetsOnStack = 0;
  55
  56    bool fSuccess = false;
  57
  58    // Check for the "this" table
  59    if (lua_istable (lua, 1))
  60    {
  61       // Found the "this" table. The object pointer is at the index 0
  62       lua_rawgeti (lua, 1, 0);
  63
  64       if (lua_islightuserdata (lua, -1))
  65       {
  66          // Found the pointer, need to cast it
  67          CLuaScript *pThis = (CLuaScript *) lua_touserdata (lua, -1);
  68
  69          // Get the method index
  70          int iMethodIdx = (int) lua_tonumber (lua, iNumberIdx);
  71
  72          // Check that the method is correct index
  73          assert (!(iMethodIdx > pThis->methods ()));
  74
  75          // Reformat the stack so our parameters are correct
  76          // Clean up the "this" table
  77          lua_remove (lua, 1);
  78          // Clean up the pThis pointer
  79          lua_remove (lua, -1);
  80
  81          // Call the class
  82          nRetsOnStack = pThis->ScriptCalling (pThis->vm (), iMethodIdx);
  83
  84          fSuccess = true;
  85       }
  86    }
  87
  88    if (fSuccess == false)
  89    {
  90       lua_pushstring (lua, "LuaCallback -> Failed to call the class function");
  91       lua_error (lua);
  92    }
  93
  94    // Number of return variables
  95    return nRetsOnStack;
  96 }
  97
  98
  99 //============================================================================
 100 // CLuaScript::CLuaScript
 101 //---------------------------------------------------------------------------
 102 // Constructor. Sets up the lua stack and the "this" table
 103 //
 104 // Parameter            Dir      Description
 105 // ---------            ---      -----------
 106 // CLuaVirtualMachine   IN       VM to run on
 107 //
 108 // Return
 109 // ------
 110 // None.
 111 //
 112 //============================================================================
 113 CLuaScript::CLuaScript (CLuaVirtualMachine& vm)
 114  : m_vm (vm), m_nMethods (0), m_iThisRef (0), m_nArgs (0)
 115 {
 116    BEGIN_LUA_CHECK (vm)
 117       // Create a reference to the "this" table. Each reference is unique
 118       lua_newtable (state);
 119       m_iThisRef = luaL_ref (state, LUA_REGISTRYINDEX);
 120
 121       // Save the "this" table to index 0 of the "this" table
 122       CLuaRestoreStack rs (vm);
 123       lua_rawgeti (state, LUA_REGISTRYINDEX, m_iThisRef);
 124       lua_pushlightuserdata (state, (void *) this);
 125       lua_rawseti (state, -2, 0);
 126    END_LUA_CHECK
 127 }
 128
 129 //============================================================================
 130 // CLuaScript::~CLuaScript
 131 //---------------------------------------------------------------------------
 132 // Destructor
 133 //
 134 // Parameter   Dir      Description
 135 // ---------   ---      -----------
 136 // None.
 137 //
 138 // Return
 139 // ------
 140 // None.
 141 //
 142 //============================================================================
 143 CLuaScript::~CLuaScript (void)
 144 {
 145    CLuaRestoreStack rs (m_vm);
 146
 147    BEGIN_LUA_CHECK (m_vm)
 148       // Get the reference "this" table
 149       lua_rawgeti (state, LUA_REGISTRYINDEX, m_iThisRef);
 150
 151       // Clear index 0
 152       lua_pushnil (state);
 153       lua_rawseti (state, -2, 0);
 154    END_LUA_CHECK
 155
 156 }
 157
 158 //============================================================================
 159 // bool CLuaScript::CompileBuffer
 160 //---------------------------------------------------------------------------
 161 // Compiles a given buffer
 162 //
 163 // Parameter   Dir      Description
 164 // ---------   ---      -----------
 165 // pbBuffer    IN       Data buffer
 166 // szLen       IN       Length of buffer
 167 //
 168 // Return
 169 // ------
 170 // Success
 171 //
 172 //============================================================================
 173 bool CLuaScript::CompileBuffer (unsigned char *pbBuffer, size_t szLen)
 174 {
 175    assert (pbBuffer != NULL && "CLuaScript::CompileBuffer ->  pbBuffer == NULL");
 176    assert (szLen != 0 && "CLuaScript::CompileBuffer -> szLen == 0");
 177    assert (m_vm.Ok () && "VM Not OK");
 178
 179    // Make sure we have the correct "this" table
 180    CLuaThis luaThis (m_vm, m_iThisRef);
 181
 182    return m_vm.RunBuffer (pbBuffer, szLen);
 183 }
 184
 185 //============================================================================
 186 // bool CLuaScript::CompileBuffer
 187 //---------------------------------------------------------------------------
 188 // Compiles a given file
 189 //
 190 // Parameter   Dir      Description
 191 // ---------   ---      -----------
 192 // strFilename IN       File name to compile
 193 //
 194 // Return
 195 // ------
 196 // Success
 197 //
 198 //============================================================================
 199 bool CLuaScript::CompileFile (const char *strFilename)
 200 {
 201    assert (strFilename != NULL && "CLuaScript::CompileFile -> strFilename == NULL");
 202    assert (m_vm.Ok () && "VM Not OK");
 203
 204    // Make sure we have the correct "this" table
 205    CLuaThis luaThis (m_vm, m_iThisRef);
 206
 207    return m_vm.RunFile (strFilename);
 208 }
 209
 210 //============================================================================
 211 // int CLuaScript::RegisterFunction
 212 //---------------------------------------------------------------------------
 213 // Registers a function with Lua
 214 //
 215 // Parameter   Dir      Description
 216 // ---------   ---      -----------
 217 // strFuncName IN       Function name
 218 //
 219 // Return
 220 // ------
 221 // Success
 222 //
 223 //============================================================================
 224 int CLuaScript::RegisterFunction (const char *strFuncName)
 225 {
 226    assert (strFuncName != NULL && "CLuaScript::RegisterFunction -> strFuncName == NULL");
 227    assert (m_vm.Ok () && "VM Not OK");
 228
 229    int iMethodIdx = -1;
 230
 231    CLuaRestoreStack rs (m_vm);
 232
 233    BEGIN_LUA_CHECK (m_vm)
 234       iMethodIdx = ++m_nMethods;
 235
 236       // Register a function with the lua script. Added it to the "this" table
 237       lua_rawgeti (state, LUA_REGISTRYINDEX, m_iThisRef);
 238
 239       // Push the function and parameters
 240       lua_pushstring (state, strFuncName);
 241       lua_pushnumber (state, (lua_Number) iMethodIdx);
 242       lua_pushcclosure (state, LuaCallback, 1);
 243       lua_settable (state, -3);
 244
 245    END_LUA_CHECK
 246
 247    return iMethodIdx;
 248 }
 249
 250 //============================================================================
 251 // bool CLuaScript::SelectScriptFunction
 252 //---------------------------------------------------------------------------
 253 // Selects a script function to run
 254 //
 255 // Parameter   Dir      Description
 256 // ---------   ---      -----------
 257 // strFuncName IN       Function name
 258 //
 259 // Return
 260 // ------
 261 // Success
 262 //
 263 //============================================================================
 264 bool CLuaScript::SelectScriptFunction (const char *strFuncName)
 265 {
 266    assert (strFuncName != NULL && "CLuaScript::SelectScriptFunction -> strFuncName == NULL");
 267    assert (m_vm.Ok () && "VM Not OK");
 268
 269    bool fSuccess = true;
 270
 271    BEGIN_LUA_CHECK (m_vm)
 272       // Look up function name
 273       lua_rawgeti (state, LUA_REGISTRYINDEX, m_iThisRef);
 274       lua_pushstring (state, strFuncName);
 275       lua_rawget (state, -2);
 276       lua_remove (state, -2);
 277
 278       // Put the "this" table back
 279       lua_rawgeti (state, LUA_REGISTRYINDEX, m_iThisRef);
 280
 281       // Check that we have a valid function
 282       if (!lua_isfunction (state, -2))
 283       {
 284          fSuccess = false;
 285          lua_pop (state, 2);
 286       }
 287       else
 288       {
 289          m_nArgs = 0;
 290          m_strFunctionName = strFuncName;
 291       }
 292    END_LUA_CHECK
 293
 294    return fSuccess;
 295 }
 296
 297 //============================================================================
 298 // bool CLuaScript::ScriptHasFunction
 299 //---------------------------------------------------------------------------
 300 // Checks to see if a function exists
 301 //
 302 // Parameter      Dir      Description
 303 // ---------      ---      -----------
 304 // strScriptName  IN       Function name
 305 //
 306 // Return
 307 // ------
 308 // Success
 309 //
 310 //============================================================================
 311 bool CLuaScript::ScriptHasFunction (const char *strScriptName)
 312 {
 313    assert (strScriptName != NULL && "CLuaScript::ScriptHasFunction -> strScriptName == NULL");
 314    assert (m_vm.Ok () && "VM Not OK");
 315
 316    CLuaRestoreStack rs (m_vm);
 317
 318    bool fFoundFunc = false;
 319
 320    BEGIN_LUA_CHECK (m_vm)
 321       lua_rawgeti (state, LUA_REGISTRYINDEX, m_iThisRef);
 322       lua_pushstring (state, strScriptName);
 323       lua_rawget (state, -2);
 324       lua_remove (state, -2);
 325
 326       if (lua_isfunction (state, -1))
 327       {
 328          fFoundFunc = true;
 329       }
 330    END_LUA_CHECK
 331
 332    return fFoundFunc;
 333 }
 334
 335 //============================================================================
 336 // void CLuaScript::AddParam
 337 //---------------------------------------------------------------------------
 338 // Adds a parameter to the parameter list
 339 //
 340 // Parameter   Dir      Description
 341 // ---------   ---      -----------
 342 // string      IN       string param
 343 //
 344 // Return
 345 // ------
 346 // None.
 347 //
 348 //============================================================================
 349 void CLuaScript::AddParam (char *string)
 350 {
 351    assert (string != NULL && "CLuaScript::AddParam -> string == NULL");
 352    assert (m_vm.Ok () && "VM Not OK");
 353
 354    BEGIN_LUA_CHECK (m_vm)
 355       lua_pushstring (state, string);
 356       ++m_nArgs;
 357    END_LUA_CHECK
 358 }
 359
 360 //============================================================================
 361 // void CLuaScript::AddParam
 362 //---------------------------------------------------------------------------
 363 // Adds a parameter to the parameter list
 364 //
 365 // Parameter   Dir      Description
 366 // ---------   ---      -----------
 367 // iInt        IN       int param
 368 //
 369 // Return
 370 // ------
 371 // None.
 372 //
 373 //============================================================================
 374 void CLuaScript::AddParam (int iInt)
 375 {
 376    assert (m_vm.Ok () && "VM Not OK");
 377
 378    BEGIN_LUA_CHECK (m_vm)
 379       lua_pushnumber (state, (lua_Number) iInt);
 380       ++m_nArgs;
 381    END_LUA_CHECK
 382 }
 383
 384 //============================================================================
 385 // void CLuaScript::AddParam
 386 //---------------------------------------------------------------------------
 387 // Adds a parameter to the parameter list
 388 //
 389 // Parameter   Dir      Description
 390 // ---------   ---      -----------
 391 // fFloat      IN       float param
 392 //
 393 // Return
 394 // ------
 395 // None.
 396 //
 397 //============================================================================
 398 void CLuaScript::AddParam (float fFloat)
 399 {
 400    assert (m_vm.Ok () && "VM Not OK");
 401
 402    BEGIN_LUA_CHECK (m_vm)
 403       lua_pushnumber (state, (lua_Number) fFloat);
 404       ++m_nArgs;
 405    END_LUA_CHECK
 406 }
 407
 408 //============================================================================
 409 // bool CLuaScript::Go
 410 //---------------------------------------------------------------------------
 411 // Runs the selected script function
 412 //
 413 // Parameter   Dir      Description
 414 // ---------   ---      -----------
 415 // nReturns    IN       Number of expected returns
 416 //
 417 // Return
 418 // ------
 419 // None.
 420 //
 421 //============================================================================
 422 bool CLuaScript::Go (int nReturns /* = 0 */)
 423 {
 424    assert (m_vm.Ok () && "VM Not OK");
 425
 426    // At this point there should be a parameters and a function on the
 427    // Lua stack. Each function get a "this" parameter as default and is
 428    // pushed onto the stack when the method is selected
 429
 430    bool fSuccess = m_vm.CallFunction (m_nArgs + 1, nReturns);
 431
 432    if (fSuccess == true && nReturns > 0)
 433    {
 434       // Check for returns
 435       HandleReturns (m_vm, m_strFunctionName);
 436       lua_pop ((lua_State *) m_vm, nReturns);
 437    }
 438
 439    return fSuccess;
 440 }