src/animator/SkScriptRuntime.cpp

/*
 * Copyright 2011 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */
#include "SkScriptRuntime.h"
#include "SkScript2.h"
#include "SkMath.h"
#include "SkParse.h"
#include "SkScriptCallBack.h"
#include "SkString.h"
#include "SkOpArray.h"

// script tokenizer

// turn text into token string
// turn number literals into inline UTF8-style values
// process operators to turn standard notation into stack notation

// defer processing until the tokens can all be resolved
// then, turn token strings into indices into the appropriate tables / dictionaries

// consider: const evaluation?

// replace script string with script tokens preceeded by special value

// need second version of script plugins that return private index of found value?
	// then would need in script index of plugin, private index

// encode brace stack push/pop as opcodes

// should token script enocde type where possible?

// current flow:
	// strip whitespace
	// if in array brace [ recurse, continue
	// if token, handle function, or array, or property (continue)
	// parse number, continue
	// parse token, continue
	// parse string literal, continue
	// if dot operator, handle dot, continue
	// if [ , handle array literal or accessor, continue
	// if ), pop (if function, break)
	// if ], pop ; if ',' break
	// handle logical ops
	// or, handle arithmetic ops
	// loop

// !!! things to do
	// add separate processing loop to advance while suppressed
	// or, include jump offset to skip suppressed code?

SkScriptRuntime::~SkScriptRuntime() {
	for (SkString** stringPtr = fTrackString.begin(); stringPtr < fTrackString.end(); stringPtr++)
		delete *stringPtr;
	for (SkOpArray** arrayPtr = fTrackArray.begin(); arrayPtr < fTrackArray.end(); arrayPtr++)
		delete *arrayPtr;
}

bool SkScriptRuntime::executeTokens(unsigned char* opCode) {
	SkOperand2 operand[2];	// 1=accumulator and 2=operand
	SkScriptEngine2::TypeOp op;
	size_t ref;
	int index, size;
	int registerLoad;
	SkScriptCallBack* callBack SK_INIT_TO_AVOID_WARNING;
	do {
	switch ((op = (SkScriptEngine2::TypeOp) *opCode++)) {
		case SkScriptEngine2::kArrayToken:	// create an array
			operand[0].fArray = new SkOpArray(SkOperand2::kNoType /*fReturnType*/);
			break;
		case SkScriptEngine2::kArrayIndex:	// array accessor
			index = operand[1].fS32;
			if (index >= operand[0].fArray->count()) {
				fError = kArrayIndexOutOfBounds;
				return false;
			}
			operand[0] = operand[0].fArray->begin()[index];
			break;
		case SkScriptEngine2::kArrayParam:	// array initializer, or function param
			*operand[0].fArray->append() = operand[1];
			break;
		case SkScriptEngine2::kCallback:
			memcpy(&index, opCode, sizeof(index));
			opCode += sizeof(index);
			callBack = fCallBackArray[index];
			break;
		case SkScriptEngine2::kFunctionCall: {
			memcpy(&ref, opCode, sizeof(ref));
			opCode += sizeof(ref);
			SkScriptCallBackFunction* callBackFunction = (SkScriptCallBackFunction*) callBack;
			if (callBackFunction->invoke(ref, operand[0].fArray, /* params */
					&operand[0] /* result */) == false) {
				fError = kFunctionCallFailed;
				return false;
			}
			} break;
		case SkScriptEngine2::kMemberOp: {
			memcpy(&ref, opCode, sizeof(ref));
			opCode += sizeof(ref);
			SkScriptCallBackMember* callBackMember = (SkScriptCallBackMember*) callBack;
			if (callBackMember->invoke(ref, operand[0].fObject, &operand[0]) == false) {
				fError = kMemberOpFailed;
				return false;
			}
			} break;
		case SkScriptEngine2::kPropertyOp: {
			memcpy(&ref, opCode, sizeof(ref));
			opCode += sizeof(ref);
			SkScriptCallBackProperty* callBackProperty = (SkScriptCallBackProperty*) callBack;
			if (callBackProperty->getResult(ref, &operand[0])== false) {
				fError = kPropertyOpFailed;
				return false;
			}
			} break;
		case SkScriptEngine2::kAccumulatorPop:
			fRunStack.pop(&operand[0]);
			break;
		case SkScriptEngine2::kAccumulatorPush:
			*fRunStack.push() = operand[0];
			break;
		case SkScriptEngine2::kIntegerAccumulator:
		case SkScriptEngine2::kIntegerOperand:
			registerLoad = op - SkScriptEngine2::kIntegerAccumulator;
			memcpy(&operand[registerLoad].fS32, opCode, sizeof(int32_t));
			opCode += sizeof(int32_t);
			break;
		case SkScriptEngine2::kScalarAccumulator:
		case SkScriptEngine2::kScalarOperand:
			registerLoad = op - SkScriptEngine2::kScalarAccumulator;
			memcpy(&operand[registerLoad].fScalar, opCode, sizeof(SkScalar));
			opCode += sizeof(SkScalar);
			break;
		case SkScriptEngine2::kStringAccumulator:
		case SkScriptEngine2::kStringOperand: {
			SkString* strPtr = new SkString();
			track(strPtr);
			registerLoad = op - SkScriptEngine2::kStringAccumulator;
			memcpy(&size, opCode, sizeof(size));
			opCode += sizeof(size);
			strPtr->set((char*) opCode, size);
			opCode += size;
			operand[registerLoad].fString = strPtr;
			} break;
		case SkScriptEngine2::kStringTrack: // call after kObjectToValue
			track(operand[0].fString);
			break;
		case SkScriptEngine2::kBoxToken: {
			SkOperand2::OpType type;
			memcpy(&type, opCode, sizeof(type));
			opCode += sizeof(type);
			SkScriptCallBackConvert* callBackBox = (SkScriptCallBackConvert*) callBack;
			if (callBackBox->convert(type, &operand[0]) == false)
				return false;
			} break;
		case SkScriptEngine2::kUnboxToken:
		case SkScriptEngine2::kUnboxToken2: {
			SkScriptCallBackConvert* callBackUnbox = (SkScriptCallBackConvert*) callBack;
			if (callBackUnbox->convert(SkOperand2::kObject, &operand[0]) == false)
				return false;
			} break;
		case SkScriptEngine2::kIfOp:
		case SkScriptEngine2::kLogicalAndInt:
			memcpy(&size, opCode, sizeof(size));
			opCode += sizeof(size);
			if (operand[0].fS32 == 0)
				opCode += size; // skip to else (or end of if predicate)
			break;
		case SkScriptEngine2::kElseOp:
			memcpy(&size, opCode, sizeof(size));
			opCode += sizeof(size);
			opCode += size; // if true: after predicate, always skip to end of else
			break;
		case SkScriptEngine2::kLogicalOrInt:
			memcpy(&size, opCode, sizeof(size));
			opCode += sizeof(size);
			if (operand[0].fS32 != 0)
				opCode += size; // skip to kToBool opcode after || predicate
			break;
		// arithmetic conversion ops
		case SkScriptEngine2::kFlipOpsOp:
			SkTSwap(operand[0], operand[1]);
			break;
		case SkScriptEngine2::kIntToString: 
		case SkScriptEngine2::kIntToString2: 
		case SkScriptEngine2::kScalarToString:
		case SkScriptEngine2::kScalarToString2:{
			SkString* strPtr = new SkString();
			track(strPtr);
			if (op == SkScriptEngine2::kIntToString || op == SkScriptEngine2::kIntToString2)
				strPtr->appendS32(operand[op - SkScriptEngine2::kIntToString].fS32);
			else
				strPtr->appendScalar(operand[op - SkScriptEngine2::kScalarToString].fScalar);
			operand[0].fString = strPtr;
			} break;
		case SkScriptEngine2::kIntToScalar:
		case SkScriptEngine2::kIntToScalar2:
			operand[0].fScalar = SkScriptEngine2::IntToScalar(operand[op - SkScriptEngine2::kIntToScalar].fS32);
			break;
		case SkScriptEngine2::kStringToInt:
			if (SkParse::FindS32(operand[0].fString->c_str(), &operand[0].fS32) == false)
				return false; 
			break;
		case SkScriptEngine2::kStringToScalar:
		case SkScriptEngine2::kStringToScalar2:
			if (SkParse::FindScalar(operand[0].fString->c_str(), 
					&operand[op - SkScriptEngine2::kStringToScalar].fScalar) == false) 
				return false; 
			break;
		case SkScriptEngine2::kScalarToInt:
			operand[0].fS32 = SkScalarFloor(operand[0].fScalar);
			break;
		// arithmetic ops
		case SkScriptEngine2::kAddInt:
			operand[0].fS32 += operand[1].fS32;
			break;
		case SkScriptEngine2::kAddScalar:
			operand[0].fScalar += operand[1].fScalar;
			break;
		case SkScriptEngine2::kAddString:
//			if (fTrackString.find(operand[1].fString) < 0) {
//				operand[1].fString = SkNEW_ARGS(SkString, (*operand[1].fString));
//				track(operand[1].fString);
//			}
			operand[0].fString->append(*operand[1].fString);
			break;
		case SkScriptEngine2::kBitAndInt:
			operand[0].fS32 &= operand[1].fS32;
			break;
		case SkScriptEngine2::kBitNotInt:
			operand[0].fS32 = ~operand[0].fS32;
			break;
		case SkScriptEngine2::kBitOrInt:
			operand[0].fS32 |= operand[1].fS32;
			break;
		case SkScriptEngine2::kDivideInt:
			SkASSERT(operand[1].fS32 != 0);
			if (operand[1].fS32 == 0)
				operand[0].fS32 = operand[0].fS32 == 0 ? SK_NaN32 : 
					operand[0].fS32 > 0 ? SK_MaxS32 : -SK_MaxS32;
			else
			if (operand[1].fS32 != 0) // throw error on divide by zero?
				operand[0].fS32 /= operand[1].fS32;
			break;
		case SkScriptEngine2::kDivideScalar:
			if (operand[1].fScalar == 0)
				operand[0].fScalar = operand[0].fScalar == 0 ? SK_ScalarNaN : 
					operand[0].fScalar > 0 ? SK_ScalarMax : -SK_ScalarMax;
			else
				operand[0].fScalar = SkScalarDiv(operand[0].fScalar, operand[1].fScalar);
			break;
		case SkScriptEngine2::kEqualInt:
			operand[0].fS32 = operand[0].fS32 == operand[1].fS32;
			break;
		case SkScriptEngine2::kEqualScalar:
			operand[0].fS32 = operand[0].fScalar == operand[1].fScalar;
			break;
		case SkScriptEngine2::kEqualString:
			operand[0].fS32 = *operand[0].fString == *operand[1].fString;
			break;
		case SkScriptEngine2::kGreaterEqualInt:
			operand[0].fS32 = operand[0].fS32 >= operand[1].fS32;
			break;
		case SkScriptEngine2::kGreaterEqualScalar:
			operand[0].fS32 = operand[0].fScalar >= operand[1].fScalar;
			break;
		case SkScriptEngine2::kGreaterEqualString:
			operand[0].fS32 = strcmp(operand[0].fString->c_str(), operand[1].fString->c_str()) >= 0;
			break;
		case SkScriptEngine2::kToBool:
			operand[0].fS32 = !! operand[0].fS32;
			break;
		case SkScriptEngine2::kLogicalNotInt:
			operand[0].fS32 = ! operand[0].fS32;
			break;
		case SkScriptEngine2::kMinusInt:
			operand[0].fS32 = -operand[0].fS32;
			break;
		case SkScriptEngine2::kMinusScalar:
			operand[0].fScalar = -operand[0].fScalar;
			break;
		case SkScriptEngine2::kModuloInt:
			operand[0].fS32 %= operand[1].fS32;
			break;
		case SkScriptEngine2::kModuloScalar:
			operand[0].fScalar = SkScalarMod(operand[0].fScalar, operand[1].fScalar);
			break;
		case SkScriptEngine2::kMultiplyInt:
			operand[0].fS32 *= operand[1].fS32;
			break;
		case SkScriptEngine2::kMultiplyScalar:
			operand[0].fScalar = SkScalarMul(operand[0].fScalar, operand[1].fScalar);
			break;
		case SkScriptEngine2::kShiftLeftInt:
			operand[0].fS32 <<= operand[1].fS32;
			break;
		case SkScriptEngine2::kShiftRightInt:
			operand[0].fS32 >>= operand[1].fS32;
			break;
		case SkScriptEngine2::kSubtractInt:
			operand[0].fS32 -= operand[1].fS32;
			break;
		case SkScriptEngine2::kSubtractScalar:
			operand[0].fScalar -= operand[1].fScalar;
			break;
		case SkScriptEngine2::kXorInt:
			operand[0].fS32 ^= operand[1].fS32;
			break;
		case SkScriptEngine2::kEnd:
			goto done;
		case SkScriptEngine2::kNop:
				SkASSERT(0);
    default:
        break;
	}
	} while (true);
done:
	fRunStack.push(operand[0]);
	return true;
}

bool SkScriptRuntime::getResult(SkOperand2* result) {
	if (fRunStack.count() == 0)
		return false;
	fRunStack.pop(result);
	return true;
}

void SkScriptRuntime::track(SkOpArray* array) { 
	SkASSERT(fTrackArray.find(array) < 0);  
	*fTrackArray.append() = array; 
}

void SkScriptRuntime::track(SkString* string) { 
	SkASSERT(fTrackString.find(string) < 0);  
	*fTrackString.append() = string; 
}

void SkScriptRuntime::untrack(SkOpArray* array) {
	int index = fTrackArray.find(array);
	SkASSERT(index >= 0);
	fTrackArray.begin()[index] = NULL;
}

void SkScriptRuntime::untrack(SkString* string) {
	int index = fTrackString.find(string);
	SkASSERT(index >= 0);
	fTrackString.begin()[index] = NULL;
}