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Create top level class VariableReferences
For use in openrewrite/rewrite-testing-frameworks#599
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src/main/java/org/openrewrite/staticanalysis/VariableReferences.java
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| Original file line number | Diff line number | Diff line change |
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| @@ -0,0 +1,132 @@ | ||
| package org.openrewrite.staticanalysis; | ||
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| import org.jspecify.annotations.Nullable; | ||
| import org.openrewrite.Cursor; | ||
| import org.openrewrite.Tree; | ||
| import org.openrewrite.java.JavaIsoVisitor; | ||
| import org.openrewrite.java.tree.Expression; | ||
| import org.openrewrite.java.tree.J; | ||
| import org.openrewrite.java.tree.Statement; | ||
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| import java.util.ArrayList; | ||
| import java.util.List; | ||
| import java.util.function.Predicate; | ||
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| public class VariableReferences { | ||
| private static boolean isIncrementKind(Cursor tree) { | ||
| return tree.getValue() instanceof J.Unary && ((J.Unary) tree.getValue()).getOperator().isModifying(); | ||
| } | ||
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| private static @Nullable Cursor dropParentWhile(Predicate<Object> valuePredicate, Cursor cursor) { | ||
| while (cursor != null && valuePredicate.test(cursor.getValue())) { | ||
| cursor = cursor.getParent(); | ||
| } | ||
| return cursor; | ||
| } | ||
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| private static @Nullable Cursor dropParentUntil(Predicate<Object> valuePredicate, Cursor cursor) { | ||
| while (cursor != null && !valuePredicate.test(cursor.getValue())) { | ||
| cursor = cursor.getParent(); | ||
| } | ||
| return cursor; | ||
| } | ||
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| private static boolean isRhsValue(Cursor tree) { | ||
| if (!(tree.getValue() instanceof J.Identifier)) { | ||
| return false; | ||
| } | ||
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| Cursor parent = dropParentWhile(J.Parentheses.class::isInstance, tree.getParent()); | ||
| assert parent != null; | ||
| if (parent.getValue() instanceof J.Assignment) { | ||
| if (dropParentUntil(J.ControlParentheses.class::isInstance, parent) != null) { | ||
| return true; | ||
| } | ||
| J.Assignment assignment = parent.getValue(); | ||
| return assignment.getVariable() != tree.getValue(); | ||
| } | ||
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| if (parent.getValue() instanceof J.VariableDeclarations.NamedVariable) { | ||
| J.VariableDeclarations.NamedVariable namedVariable = parent.getValue(); | ||
| return namedVariable.getName() != tree.getValue(); | ||
| } | ||
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| if (parent.getValue() instanceof J.AssignmentOperation) { | ||
| J.AssignmentOperation assignmentOperation = parent.getValue(); | ||
| if (assignmentOperation.getVariable() == tree.getValue()) { | ||
| Tree grandParent = parent.getParentTreeCursor().getValue(); | ||
| return (grandParent instanceof Expression || grandParent instanceof J.Return); | ||
| } | ||
| } | ||
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| return !(isIncrementKind(parent) && parent.getParentTreeCursor().getValue() instanceof J.Block); | ||
| } | ||
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| /** | ||
| * An identifier is considered a right-hand side ("rhs") read operation if it is not used as the left operand | ||
| * of an assignment, nor as the operand of a stand-alone increment. | ||
| * | ||
| * @param j The subtree to search. | ||
| * @param target A {@link J.Identifier} to check for usages. | ||
| * @return found {@link J} locations of "right-hand" read calls. | ||
| */ | ||
| public static List<J> findRhsReferences(J j, J.Identifier target) { | ||
| final List<J> refs = new ArrayList<>(); | ||
| new JavaIsoVisitor<List<J>>() { | ||
| @Override | ||
| public J.Identifier visitIdentifier(J.Identifier identifier, List<J> ctx) { | ||
| if (identifier.getSimpleName().equals(target.getSimpleName()) && isRhsValue(getCursor())) { | ||
| ctx.add(identifier); | ||
| } | ||
| return super.visitIdentifier(identifier, ctx); | ||
| } | ||
| }.visit(j, refs); | ||
| return refs; | ||
| } | ||
|
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| /** | ||
| * @param j The subtree to search. | ||
| * @param target A {@link J.Identifier} to check for usages. | ||
| * @return found {@link Statement} locations of "left-hand" assignment write calls. | ||
| */ | ||
| public static List<Statement> findLhsReferences(J j, J.Identifier target) { | ||
| JavaIsoVisitor<List<Statement>> visitor = new JavaIsoVisitor<List<Statement>>() { | ||
| @Override | ||
| public J.Assignment visitAssignment(J.Assignment assignment, List<Statement> ctx) { | ||
| if (assignment.getVariable() instanceof J.Identifier) { | ||
| J.Identifier i = (J.Identifier) assignment.getVariable(); | ||
| if (i.getSimpleName().equals(target.getSimpleName())) { | ||
| ctx.add(assignment); | ||
| } | ||
| } | ||
| return super.visitAssignment(assignment, ctx); | ||
| } | ||
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| @Override | ||
| public J.AssignmentOperation visitAssignmentOperation(J.AssignmentOperation assignOp, List<Statement> ctx) { | ||
| if (assignOp.getVariable() instanceof J.Identifier) { | ||
| J.Identifier i = (J.Identifier) assignOp.getVariable(); | ||
| if (i.getSimpleName().equals(target.getSimpleName())) { | ||
| ctx.add(assignOp); | ||
| } | ||
| } | ||
| return super.visitAssignmentOperation(assignOp, ctx); | ||
| } | ||
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| @Override | ||
| public J.Unary visitUnary(J.Unary unary, List<Statement> ctx) { | ||
| if (unary.getExpression() instanceof J.Identifier) { | ||
| J.Identifier i = (J.Identifier) unary.getExpression(); | ||
| if (i.getSimpleName().equals(target.getSimpleName())) { | ||
| ctx.add(unary); | ||
| } | ||
| } | ||
| return super.visitUnary(unary, ctx); | ||
| } | ||
| }; | ||
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| List<Statement> refs = new ArrayList<>(); | ||
| visitor.visit(j, refs); | ||
| return refs; | ||
| } | ||
| } |