| /* |
| * Copyright 2003-2012 Dave Griffith, Bas Leijdekkers |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package com.siyeh.ig.performance; |
| |
| import com.intellij.codeInspection.ProblemDescriptor; |
| import com.intellij.openapi.project.Project; |
| import com.intellij.psi.*; |
| import com.intellij.psi.tree.IElementType; |
| import com.intellij.util.IncorrectOperationException; |
| import com.siyeh.InspectionGadgetsBundle; |
| import com.siyeh.ig.BaseInspection; |
| import com.siyeh.ig.BaseInspectionVisitor; |
| import com.siyeh.ig.InspectionGadgetsFix; |
| import com.siyeh.ig.PsiReplacementUtil; |
| import com.siyeh.ig.psiutils.ExpressionUtils; |
| import com.siyeh.ig.psiutils.ParenthesesUtils; |
| import com.siyeh.ig.psiutils.SideEffectChecker; |
| import com.siyeh.ig.psiutils.VariableAccessUtils; |
| import org.jetbrains.annotations.NonNls; |
| import org.jetbrains.annotations.NotNull; |
| import org.jetbrains.annotations.Nullable; |
| |
| public class ManualArrayCopyInspection extends BaseInspection { |
| |
| @Override |
| @NotNull |
| public String getDisplayName() { |
| return InspectionGadgetsBundle.message( |
| "manual.array.copy.display.name"); |
| } |
| |
| @Override |
| public boolean isEnabledByDefault() { |
| return true; |
| } |
| |
| @Override |
| @NotNull |
| protected String buildErrorString(Object... infos) { |
| return InspectionGadgetsBundle.message( |
| "manual.array.copy.problem.descriptor"); |
| } |
| |
| @Override |
| public BaseInspectionVisitor buildVisitor() { |
| return new ManualArrayCopyVisitor(); |
| } |
| |
| @Override |
| public InspectionGadgetsFix buildFix(Object... infos) { |
| final Boolean decrement = (Boolean)infos[0]; |
| return new ManualArrayCopyFix(decrement.booleanValue()); |
| } |
| |
| private static class ManualArrayCopyFix extends InspectionGadgetsFix { |
| |
| private final boolean decrement; |
| |
| public ManualArrayCopyFix(boolean decrement) { |
| this.decrement = decrement; |
| } |
| |
| @Override |
| @NotNull |
| public String getName() { |
| return InspectionGadgetsBundle.message("manual.array.copy.replace.quickfix"); |
| } |
| @Override |
| @NotNull |
| public String getFamilyName() { |
| return getName(); |
| } |
| |
| @Override |
| public void doFix(Project project, ProblemDescriptor descriptor) throws IncorrectOperationException { |
| final PsiElement forElement = descriptor.getPsiElement(); |
| final PsiForStatement forStatement = (PsiForStatement)forElement.getParent(); |
| final String newExpression = buildSystemArrayCopyText(forStatement); |
| if (newExpression == null) { |
| return; |
| } |
| PsiReplacementUtil.replaceStatement(forStatement, newExpression); |
| } |
| |
| @Nullable |
| private String buildSystemArrayCopyText(PsiForStatement forStatement) throws IncorrectOperationException { |
| final PsiExpression condition = forStatement.getCondition(); |
| final PsiBinaryExpression binaryExpression = (PsiBinaryExpression)ParenthesesUtils.stripParentheses(condition); |
| if (binaryExpression == null) { |
| return null; |
| } |
| final IElementType tokenType = binaryExpression.getOperationTokenType(); |
| final PsiExpression limit; |
| if (decrement ^ JavaTokenType.LT.equals(tokenType) || JavaTokenType.LE.equals(tokenType)) { |
| limit = binaryExpression.getROperand(); |
| } |
| else { |
| limit = binaryExpression.getLOperand(); |
| } |
| if (limit == null) { |
| return null; |
| } |
| final PsiStatement initialization = forStatement.getInitialization(); |
| if (initialization == null) { |
| return null; |
| } |
| if (!(initialization instanceof PsiDeclarationStatement)) { |
| return null; |
| } |
| final PsiDeclarationStatement declaration = (PsiDeclarationStatement)initialization; |
| final PsiElement[] declaredElements = declaration.getDeclaredElements(); |
| if (declaredElements.length != 1) { |
| return null; |
| } |
| final PsiElement declaredElement = declaredElements[0]; |
| if (!(declaredElement instanceof PsiLocalVariable)) { |
| return null; |
| } |
| final PsiLocalVariable variable = (PsiLocalVariable)declaredElement; |
| final String lengthText; |
| final PsiExpression initializer = variable.getInitializer(); |
| if (decrement) { |
| lengthText = buildLengthText(initializer, limit, JavaTokenType.LE.equals(tokenType) || JavaTokenType.GE.equals(tokenType)); |
| } |
| else { |
| lengthText = buildLengthText(limit, initializer, JavaTokenType.LE.equals(tokenType) || JavaTokenType.GE.equals(tokenType)); |
| } |
| if (lengthText == null) { |
| return null; |
| } |
| final PsiArrayAccessExpression lhs = getLhsArrayAccessExpression(forStatement); |
| if (lhs == null) { |
| return null; |
| } |
| final PsiExpression lArray = lhs.getArrayExpression(); |
| final String toArrayText = lArray.getText(); |
| final PsiArrayAccessExpression rhs = getRhsArrayAccessExpression(forStatement); |
| if (rhs == null) { |
| return null; |
| } |
| final PsiExpression rArray = rhs.getArrayExpression(); |
| final String fromArrayText = rArray.getText(); |
| final PsiExpression rhsIndexExpression = rhs.getIndexExpression(); |
| final PsiExpression strippedRhsIndexExpression = ParenthesesUtils.stripParentheses(rhsIndexExpression); |
| final PsiExpression limitExpression; |
| if (decrement) { |
| limitExpression = limit; |
| } |
| else { |
| limitExpression = initializer; |
| } |
| final String fromOffsetText = buildOffsetText(strippedRhsIndexExpression, variable, limitExpression, decrement && |
| (JavaTokenType.LT.equals(tokenType) || JavaTokenType.GT.equals(tokenType))); |
| final PsiExpression lhsIndexExpression = lhs.getIndexExpression(); |
| final PsiExpression strippedLhsIndexExpression = ParenthesesUtils.stripParentheses(lhsIndexExpression); |
| final String toOffsetText = buildOffsetText(strippedLhsIndexExpression, variable, |
| limitExpression, decrement && (JavaTokenType.LT.equals(tokenType) || JavaTokenType.GT.equals(tokenType))); |
| @NonNls final StringBuilder buffer = new StringBuilder(60); |
| buffer.append("System.arraycopy("); |
| buffer.append(fromArrayText); |
| buffer.append(", "); |
| buffer.append(fromOffsetText); |
| buffer.append(", "); |
| buffer.append(toArrayText); |
| buffer.append(", "); |
| buffer.append(toOffsetText); |
| buffer.append(", "); |
| buffer.append(lengthText); |
| buffer.append(");"); |
| return buffer.toString(); |
| } |
| |
| @Nullable |
| private static PsiArrayAccessExpression getLhsArrayAccessExpression( |
| PsiForStatement forStatement) { |
| PsiStatement body = forStatement.getBody(); |
| while (body instanceof PsiBlockStatement) { |
| final PsiBlockStatement blockStatement = |
| (PsiBlockStatement)body; |
| final PsiCodeBlock codeBlock = blockStatement.getCodeBlock(); |
| final PsiStatement[] statements = codeBlock.getStatements(); |
| if (statements.length == 2) { |
| body = statements[1]; |
| } |
| else if (statements.length == 1) { |
| body = statements[0]; |
| } |
| else { |
| return null; |
| } |
| } |
| if (!(body instanceof PsiExpressionStatement)) { |
| return null; |
| } |
| final PsiExpressionStatement expressionStatement = |
| (PsiExpressionStatement)body; |
| final PsiExpression expression = |
| expressionStatement.getExpression(); |
| if (!(expression instanceof PsiAssignmentExpression)) { |
| return null; |
| } |
| final PsiAssignmentExpression assignmentExpression = |
| (PsiAssignmentExpression)expression; |
| final PsiExpression lhs = assignmentExpression.getLExpression(); |
| |
| final PsiExpression deparenthesizedExpression = |
| ParenthesesUtils.stripParentheses(lhs); |
| if (!(deparenthesizedExpression instanceof |
| PsiArrayAccessExpression)) { |
| return null; |
| } |
| return (PsiArrayAccessExpression)deparenthesizedExpression; |
| } |
| |
| @Nullable |
| private static PsiArrayAccessExpression getRhsArrayAccessExpression( |
| PsiForStatement forStatement) { |
| PsiStatement body = forStatement.getBody(); |
| while (body instanceof PsiBlockStatement) { |
| final PsiBlockStatement blockStatement = |
| (PsiBlockStatement)body; |
| final PsiCodeBlock codeBlock = blockStatement.getCodeBlock(); |
| final PsiStatement[] statements = codeBlock.getStatements(); |
| if (statements.length == 1 || statements.length == 2) { |
| body = statements[0]; |
| } |
| else { |
| return null; |
| } |
| } |
| final PsiExpression arrayAccessExpression; |
| if (body instanceof PsiDeclarationStatement) { |
| final PsiDeclarationStatement declarationStatement = |
| (PsiDeclarationStatement)body; |
| final PsiElement[] declaredElements = |
| declarationStatement.getDeclaredElements(); |
| if (declaredElements.length != 1) { |
| return null; |
| } |
| final PsiElement declaredElement = declaredElements[0]; |
| if (!(declaredElement instanceof PsiVariable)) { |
| return null; |
| } |
| final PsiVariable variable = (PsiVariable)declaredElement; |
| arrayAccessExpression = variable.getInitializer(); |
| } |
| else if (body instanceof PsiExpressionStatement) { |
| final PsiExpressionStatement expressionStatement = |
| (PsiExpressionStatement)body; |
| final PsiExpression expression = |
| expressionStatement.getExpression(); |
| if (!(expression instanceof PsiAssignmentExpression)) { |
| return null; |
| } |
| final PsiAssignmentExpression assignmentExpression = |
| (PsiAssignmentExpression)expression; |
| arrayAccessExpression = assignmentExpression.getRExpression(); |
| } |
| else { |
| return null; |
| } |
| final PsiExpression unparenthesizedExpression = |
| ParenthesesUtils.stripParentheses(arrayAccessExpression); |
| if (!(unparenthesizedExpression instanceof |
| PsiArrayAccessExpression)) { |
| return null; |
| } |
| return (PsiArrayAccessExpression)unparenthesizedExpression; |
| } |
| |
| @NonNls |
| @Nullable |
| private static String buildLengthText(PsiExpression max, PsiExpression min, boolean plusOne) { |
| max = ParenthesesUtils.stripParentheses(max); |
| if (max == null) { |
| return null; |
| } |
| min = ParenthesesUtils.stripParentheses(min); |
| if (min == null) { |
| return buildExpressionText(max, plusOne, false); |
| } |
| final Object minConstant = ExpressionUtils.computeConstantExpression(min); |
| if (minConstant instanceof Number) { |
| final Number minNumber = (Number)minConstant; |
| final int minValue; |
| if (plusOne) { |
| minValue = minNumber.intValue() - 1; |
| } |
| else { |
| minValue = minNumber.intValue(); |
| } |
| if (minValue == 0) { |
| return buildExpressionText(max, false, false); |
| } |
| if (max instanceof PsiLiteralExpression) { |
| final Object maxConstant = ExpressionUtils.computeConstantExpression(max); |
| if (maxConstant instanceof Number) { |
| final Number number = (Number)maxConstant; |
| return String.valueOf(number.intValue() - minValue); |
| } |
| } |
| final String maxText = buildExpressionText(max, false, false); |
| if (minValue > 0) { |
| return maxText + '-' + minValue; |
| } |
| else { |
| return maxText + '+' + -minValue; |
| } |
| } |
| final int precedence = ParenthesesUtils.getPrecedence(min); |
| final String minText; |
| if (precedence >= ParenthesesUtils.ADDITIVE_PRECEDENCE) { |
| minText = '(' + min.getText() + ')'; |
| } |
| else { |
| minText = min.getText(); |
| } |
| final String maxText = buildExpressionText(max, plusOne, false); |
| return maxText + '-' + minText; |
| } |
| |
| private static String buildExpressionText(PsiExpression expression, boolean plusOne, boolean parenthesize) { |
| if (!plusOne) { |
| final int precedence = ParenthesesUtils.getPrecedence(expression); |
| if (precedence > ParenthesesUtils.ADDITIVE_PRECEDENCE) { |
| return '(' + expression.getText() + ')'; |
| } |
| else { |
| if (parenthesize && precedence >= ParenthesesUtils.ADDITIVE_PRECEDENCE) { |
| return '(' + expression.getText() + ')'; |
| } |
| return expression.getText(); |
| } |
| } |
| if (expression instanceof PsiBinaryExpression) { |
| final PsiBinaryExpression binaryExpression = (PsiBinaryExpression)expression; |
| final IElementType tokenType = binaryExpression.getOperationTokenType(); |
| if (tokenType == JavaTokenType.MINUS) { |
| final PsiExpression rhs = binaryExpression.getROperand(); |
| if (ExpressionUtils.isOne(rhs)) { |
| return binaryExpression.getLOperand().getText(); |
| } |
| } |
| } |
| else if (expression instanceof PsiLiteralExpression) { |
| final PsiLiteralExpression literalExpression = (PsiLiteralExpression)expression; |
| final Object value = literalExpression.getValue(); |
| if (value instanceof Integer) { |
| final Integer integer = (Integer)value; |
| return String.valueOf(integer.intValue() + 1); |
| } |
| } |
| final int precedence = ParenthesesUtils.getPrecedence(expression); |
| final String result; |
| if (precedence > ParenthesesUtils.ADDITIVE_PRECEDENCE) { |
| result = '(' + expression.getText() + ")+1"; |
| } |
| else { |
| result = expression.getText() + "+1"; |
| } |
| if (parenthesize) { |
| return '(' + result + ')'; |
| } |
| return result; |
| } |
| |
| @NonNls |
| @Nullable |
| private static String buildOffsetText(PsiExpression expression, |
| PsiLocalVariable variable, |
| PsiExpression limitExpression, |
| boolean plusOne) |
| throws IncorrectOperationException { |
| if (expression == null) { |
| return null; |
| } |
| final String expressionText = expression.getText(); |
| final String variableName = variable.getName(); |
| if (expressionText.equals(variableName)) { |
| final PsiExpression initialValue = |
| ParenthesesUtils.stripParentheses(limitExpression); |
| if (initialValue == null) { |
| return null; |
| } |
| return buildExpressionText(initialValue, plusOne, false); |
| } |
| else if (expression instanceof PsiBinaryExpression) { |
| final PsiBinaryExpression binaryExpression = |
| (PsiBinaryExpression)expression; |
| final PsiExpression lhs = binaryExpression.getLOperand(); |
| final PsiExpression rhs = binaryExpression.getROperand(); |
| final String rhsText = |
| buildOffsetText(rhs, variable, limitExpression, plusOne); |
| final PsiJavaToken sign = binaryExpression.getOperationSign(); |
| final IElementType tokenType = sign.getTokenType(); |
| if (ExpressionUtils.isZero(lhs)) { |
| if (tokenType.equals(JavaTokenType.MINUS)) { |
| return '-' + rhsText; |
| } |
| return rhsText; |
| } |
| if (plusOne && tokenType.equals(JavaTokenType.MINUS) && |
| ExpressionUtils.isOne(rhs)) { |
| return buildOffsetText(lhs, variable, limitExpression, |
| false); |
| } |
| final String lhsText = buildOffsetText(lhs, variable, |
| limitExpression, plusOne); |
| if (ExpressionUtils.isZero(rhs)) { |
| return lhsText; |
| } |
| return collapseConstant(lhsText + sign.getText() + rhsText, |
| variable); |
| } |
| return collapseConstant(expression.getText(), variable); |
| } |
| |
| private static String collapseConstant(@NonNls String expressionText, |
| PsiElement context) |
| throws IncorrectOperationException { |
| final Project project = context.getProject(); |
| final JavaPsiFacade psiFacade = JavaPsiFacade.getInstance(project); |
| final PsiElementFactory factory = psiFacade.getElementFactory(); |
| final PsiExpression fromOffsetExpression = |
| factory.createExpressionFromText(expressionText, context); |
| final Object fromOffsetConstant = |
| ExpressionUtils.computeConstantExpression( |
| fromOffsetExpression); |
| if (fromOffsetConstant != null) { |
| return fromOffsetConstant.toString(); |
| } |
| else { |
| return expressionText; |
| } |
| } |
| } |
| |
| private static class ManualArrayCopyVisitor extends BaseInspectionVisitor { |
| |
| @Override |
| public void visitForStatement( |
| @NotNull PsiForStatement statement) { |
| super.visitForStatement(statement); |
| final PsiStatement initialization = statement.getInitialization(); |
| if (!(initialization instanceof PsiDeclarationStatement)) { |
| return; |
| } |
| final PsiDeclarationStatement declaration = |
| (PsiDeclarationStatement)initialization; |
| final PsiElement[] declaredElements = |
| declaration.getDeclaredElements(); |
| if (declaredElements.length != 1) { |
| return; |
| } |
| final PsiElement declaredElement = declaredElements[0]; |
| if (!(declaredElement instanceof PsiLocalVariable)) { |
| return; |
| } |
| final PsiLocalVariable variable = (PsiLocalVariable)declaredElement; |
| final PsiExpression initialValue = variable.getInitializer(); |
| if (initialValue == null) { |
| return; |
| } |
| final PsiStatement update = statement.getUpdate(); |
| final boolean decrement; |
| if (VariableAccessUtils.variableIsIncremented(variable, update)) { |
| decrement = false; |
| } |
| else if (VariableAccessUtils.variableIsDecremented(variable, |
| update)) { |
| decrement = true; |
| } |
| else { |
| return; |
| } |
| final PsiExpression condition = statement.getCondition(); |
| if (decrement) { |
| if (!ExpressionUtils.isVariableGreaterThanComparison( |
| condition, variable)) { |
| return; |
| } |
| } |
| else { |
| if (!ExpressionUtils.isVariableLessThanComparison( |
| condition, variable)) { |
| return; |
| } |
| } |
| final PsiStatement body = statement.getBody(); |
| if (!bodyIsArrayCopy(body, variable, null)) { |
| return; |
| } |
| registerStatementError(statement, Boolean.valueOf(decrement)); |
| } |
| |
| private static boolean bodyIsArrayCopy( |
| PsiStatement body, PsiVariable variable, |
| @Nullable PsiVariable variable2) { |
| if (body instanceof PsiExpressionStatement) { |
| final PsiExpressionStatement exp = |
| (PsiExpressionStatement)body; |
| final PsiExpression expression = exp.getExpression(); |
| return expressionIsArrayCopy(expression, variable, variable2); |
| } |
| else if (body instanceof PsiBlockStatement) { |
| final PsiBlockStatement blockStatement = |
| (PsiBlockStatement)body; |
| final PsiCodeBlock codeBlock = blockStatement.getCodeBlock(); |
| final PsiStatement[] statements = codeBlock.getStatements(); |
| if (statements.length == 1) { |
| return bodyIsArrayCopy(statements[0], variable, variable2); |
| } |
| else if (statements.length == 2) { |
| final PsiStatement statement = statements[0]; |
| if (!(statement instanceof PsiDeclarationStatement)) { |
| return false; |
| } |
| final PsiDeclarationStatement declarationStatement = |
| (PsiDeclarationStatement)statement; |
| final PsiElement[] declaredElements = |
| declarationStatement.getDeclaredElements(); |
| if (declaredElements.length != 1) { |
| return false; |
| } |
| final PsiElement declaredElement = declaredElements[0]; |
| if (!(declaredElement instanceof PsiVariable)) { |
| return false; |
| } |
| final PsiVariable localVariable = |
| (PsiVariable)declaredElement; |
| final PsiExpression initializer = |
| localVariable.getInitializer(); |
| if (!ExpressionUtils.isOffsetArrayAccess(initializer, |
| variable)) { |
| return false; |
| } |
| return bodyIsArrayCopy(statements[1], variable, |
| localVariable); |
| } |
| } |
| return false; |
| } |
| |
| private static boolean expressionIsArrayCopy( |
| @Nullable PsiExpression expression, |
| @NotNull PsiVariable variable, |
| @Nullable PsiVariable variable2) { |
| final PsiExpression strippedExpression = |
| ParenthesesUtils.stripParentheses(expression); |
| if (strippedExpression == null) { |
| return false; |
| } |
| if (!(strippedExpression instanceof PsiAssignmentExpression)) { |
| return false; |
| } |
| final PsiAssignmentExpression assignment = |
| (PsiAssignmentExpression)strippedExpression; |
| final IElementType tokenType = assignment.getOperationTokenType(); |
| if (!tokenType.equals(JavaTokenType.EQ)) { |
| return false; |
| } |
| final PsiExpression lhs = assignment.getLExpression(); |
| if (SideEffectChecker.mayHaveSideEffects(lhs)) { |
| return false; |
| } |
| if (!ExpressionUtils.isOffsetArrayAccess(lhs, variable)) { |
| return false; |
| } |
| final PsiExpression rhs = assignment.getRExpression(); |
| if (rhs == null) { |
| return false; |
| } |
| if (SideEffectChecker.mayHaveSideEffects(rhs)) { |
| return false; |
| } |
| if (!areExpressionsCopyable(lhs, rhs)) { |
| return false; |
| } |
| final PsiType type = lhs.getType(); |
| if (type instanceof PsiPrimitiveType) { |
| final PsiExpression strippedLhs = |
| ParenthesesUtils.stripParentheses(lhs); |
| final PsiExpression strippedRhs = |
| ParenthesesUtils.stripParentheses(rhs); |
| if (!areExpressionsCopyable(strippedLhs, strippedRhs)) { |
| return false; |
| } |
| } |
| if (variable2 == null) { |
| return ExpressionUtils.isOffsetArrayAccess(rhs, variable); |
| } |
| else { |
| return VariableAccessUtils.evaluatesToVariable(rhs, variable2); |
| } |
| } |
| |
| private static boolean areExpressionsCopyable( |
| @Nullable PsiExpression lhs, @Nullable PsiExpression rhs) { |
| if (lhs == null || rhs == null) { |
| return false; |
| } |
| final PsiType lhsType = lhs.getType(); |
| if (lhsType == null) { |
| return false; |
| } |
| final PsiType rhsType = rhs.getType(); |
| if (rhsType == null) { |
| return false; |
| } |
| if (lhsType instanceof PsiPrimitiveType) { |
| if (!lhsType.equals(rhsType)) { |
| return false; |
| } |
| } |
| else { |
| if (!lhsType.isAssignableFrom(rhsType) || |
| rhsType instanceof PsiPrimitiveType) { |
| return false; |
| } |
| } |
| return true; |
| } |
| } |
| } |
