Android Recycle Rule. Closes #212

Author: luiscruz

plugin/src/main/java/org/autorefactor/refactoring/rules/AllRefactoringRules.java

@@ -116,6 +116,7 @@ public static List<RefactoringRule> getAllRefactoringRules() {
                 new ReplaceQualifiedNamesBySimpleNamesRefactoring(),
                 new RemoveEmptyLinesRefactoring(),
                 new AndroidWakeLockRefactoring(),
+                new AndroidRecycleRefactoring(),
                 new SwitchRefactoring());
     }
 

plugin/src/main/java/org/autorefactor/refactoring/rules/AndroidRecycleRefactoring.java

@@ -0,0 +1,325 @@
+/*
+ * AutoRefactor - Eclipse plugin to automatically refactor Java code bases.
+ *
+ * Copyright (C) 2016 Luis Cruz - Android Refactoring Rules
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program under LICENSE-GNUGPL.  If not, see
+ * <http://www.gnu.org/licenses/>.
+ *
+ *
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution under LICENSE-ECLIPSE, and is
+ * available at http://www.eclipse.org/legal/epl-v10.html
+ */
+package org.autorefactor.refactoring.rules;
+
+import org.eclipse.jdt.core.dom.ASTNode;
+import org.eclipse.jdt.core.dom.ASTVisitor;
+import org.eclipse.jdt.core.dom.Assignment;
+import org.eclipse.jdt.core.dom.Block;
+import org.eclipse.jdt.core.dom.ExpressionStatement;
+import org.eclipse.jdt.core.dom.IMethodBinding;
+import org.eclipse.jdt.core.dom.ITypeBinding;
+import org.eclipse.jdt.core.dom.MethodInvocation;
+import org.eclipse.jdt.core.dom.SimpleName;
+import org.eclipse.jdt.core.dom.Statement;
+import org.eclipse.jdt.core.dom.VariableDeclarationFragment;
+import static org.autorefactor.refactoring.ASTHelper.*;
+import static org.eclipse.jdt.core.dom.ASTNode.*;
+import org.autorefactor.refactoring.ASTBuilder;
+import org.autorefactor.refactoring.Refactorings;
+
+/*
+ * TODO when the last use of resource is as arg of a method invocation,
+ * it should be assumed that the given method will take care of the release.
+ * TODO Track local variables. E.g., when a TypedArray a is assigned to variable b,
+ * release() should be called only in one variable.
+ * TODO (low priority) check whether resources are being used after release.
+ * TODO add support for FragmentTransaction.beginTransaction(). It can use method
+ * chaining (which means local variable might not be present) and it can be released
+ * by two methods: commit() and commitAllowingStateLoss().
+ */
+
+/** See {@link #getDescription()} method. */
+public class AndroidRecycleRefactoring extends AbstractRefactoringRule {
+
+    @Override
+    public String getDescription() {
+        return "Many resources, such as TypedArrays, VelocityTrackers, etc., should be "
+                + "recycled (with a recycle()/close() call) after use. " + "Inspired from "
+                + "https://android.googlesource.com/platform/tools/base/+/master/lint/libs/lint-checks/src/main/"
+                + "java/com/android/tools/lint/checks/CleanupDetector.java";
+    }
+
+    @Override
+    public String getName() {
+        return "RecycleRefactoring";
+    }
+
+    private static boolean isMethodIgnoringParameters(MethodInvocation node, String typeQualifiedName,
+            String methodName) {
+        if (node == null) {
+            return false;
+        }
+        final IMethodBinding methodBinding = node.resolveMethodBinding();
+        if (methodBinding == null || !methodName.equals(methodBinding.getName())) {
+            return false;
+        }
+        final ITypeBinding declaringClazz = methodBinding.getDeclaringClass();
+        return instanceOf(declaringClazz, typeQualifiedName);
+    }
+
+    private static boolean isMethodIgnoringParameters(MethodInvocation node, String typeQualifiedName,
+            String... methodNames) {
+        for (String methodName : methodNames) {
+            if (isMethodIgnoringParameters(node, typeQualifiedName, methodName)) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    private String methodNameToCleanupResource(MethodInvocation node) {
+        if (isMethodIgnoringParameters(
+                node,
+                "android.database.sqlite.SQLiteDatabase",
+                "query", "rawQuery", "queryWithFactory", "rawQueryWithFactory")
+        ) {
+            return "close";
+        } else if (isMethodIgnoringParameters(
+                node,
+                "android.content.ContentProvider",
+                "query" , "rawQuery", "queryWithFactory", "rawQueryWithFactory")
+        ) {
+            return "close";
+        } else if (isMethodIgnoringParameters(
+                node,
+                "android.content.ContentResolver",
+                "query", "rawQuery", "queryWithFactory", "rawQueryWithFactory")
+        ) {
+            return "close";
+        } else if (isMethodIgnoringParameters(
+                node,
+                "android.content.ContentProviderClient",
+                "query", "rawQuery", "queryWithFactory", "rawQueryWithFactory")
+        ) {
+            return "close";
+        } else if (isMethodIgnoringParameters(
+                node,
+                "android.content.Context",
+                "obtainStyledAttributes")
+        ) {
+            return "recycle";
+        } else if (isMethodIgnoringParameters(
+                node,
+                "android.content.res.Resources",
+                "obtainTypedArray", "obtainAttributes", "obtainStyledAttributes")
+        ) {
+            return "recycle";
+        } else if (isMethod(
+                node,
+                "android.view.VelocityTracker",
+                "obtain")
+        ) {
+            return "recycle";
+        } else if (isMethodIgnoringParameters(
+                node,
+                "android.os.Handler",
+                "obtainMessage")
+        ) {
+            return "recycle";
+        } else if (isMethodIgnoringParameters(
+                node,
+                "android.os.Message",
+                "obtain")
+        ) {
+            return "recycle";
+        } else if (isMethod(
+                node,
+                "android.view.MotionEvent",
+                "obtainNoHistory", "android.view.MotionEvent")
+        ) {
+            return "recycle";
+        } else if (isMethodIgnoringParameters(
+                node,
+                "android.view.MotionEvent",
+                "obtain")
+        ) {
+            return "recycle";
+        } else if (isMethod(
+                node,
+                "android.os.Parcel",
+                "obtain")
+        ) {
+            return "recycle";
+        } else if (isMethodIgnoringParameters(
+                node,
+                "android.content.ContentResolver",
+                "acquireContentProviderClient")
+        ) {
+            return "release";
+        }
+        return null;
+    }
+
+    @Override
+    public boolean visit(MethodInvocation node) {
+        String recycleMethodName = methodNameToCleanupResource(node);
+        if (recycleMethodName != null) {
+            SimpleName cursorExpression;
+            ASTNode variableAssignmentNode;
+            VariableDeclarationFragment variableDeclarationFragment =
+                    (VariableDeclarationFragment) getFirstAncestorOrNull(node, VariableDeclarationFragment.class);
+            if (variableDeclarationFragment != null) {
+                cursorExpression = variableDeclarationFragment.getName();
+                variableAssignmentNode = variableDeclarationFragment;
+            } else {
+                Assignment variableAssignment = getAncestor(node, Assignment.class);
+                cursorExpression = (SimpleName) variableAssignment.getLeftHandSide();
+                variableAssignmentNode = variableAssignment;
+            }
+            // Check whether it has been closed
+            ClosePresenceChecker closePresenceChecker = new ClosePresenceChecker(cursorExpression, recycleMethodName);
+            VisitorDecorator visitor = new VisitorDecorator(variableAssignmentNode, cursorExpression,
+                    closePresenceChecker);
+            Block block = getAncestor(node, Block.class);
+            block.accept(visitor);
+            if (!closePresenceChecker.isClosePresent()) {
+                Statement lastCursorAccess = closePresenceChecker.getLastCursorStatementInBlock(block);
+                if (lastCursorAccess.getNodeType() != ASTNode.RETURN_STATEMENT) {
+                    final ASTBuilder b = this.ctx.getASTBuilder();
+                    final Refactorings r = this.ctx.getRefactorings();
+                    MethodInvocation closeInvocation = b.invoke(b.copy(cursorExpression), recycleMethodName);
+                    ExpressionStatement expressionStatement = b.getAST().newExpressionStatement(closeInvocation);
+                    r.insertAfter(expressionStatement, lastCursorAccess);
+                    return DO_NOT_VISIT_SUBTREE;
+                }
+            }
+        }
+        return VISIT_SUBTREE;
+    }
+
+    private class ClosePresenceChecker extends ASTVisitor {
+        private boolean closePresent;
+        private SimpleName lastCursorUse;
+        private SimpleName cursorSimpleName;
+        private String recycleMethodName;
+
+        /**
+         * @param cursorSimpleName Variable name of cursor
+         * @param recycleMethodName Recycle method name
+         */
+        public ClosePresenceChecker(SimpleName cursorSimpleName, String recycleMethodName) {
+            this.cursorSimpleName = cursorSimpleName;
+            this.recycleMethodName = recycleMethodName;
+        }
+
+        public boolean isClosePresent() {
+            return closePresent;
+        }
+
+        /**
+         * Returns the last statement in the block where the cursor was accessed
+         * before being assigned again or destroyed.
+         * @param block Block with the Statement that we want to find
+         * @return
+         */
+        public Statement getLastCursorStatementInBlock(Block block) {
+            ASTNode lastCursorStatement = this.lastCursorUse.getParent();
+            while (lastCursorStatement != null && !block.statements().contains(lastCursorStatement)) {
+                lastCursorStatement = getAncestor(lastCursorStatement, Statement.class);
+            }
+            return (Statement) lastCursorStatement;
+        }
+
+        @Override
+        public boolean visit(MethodInvocation node) {
+            if (isSameLocalVariable(cursorSimpleName, node.getExpression())) {
+                if (this.recycleMethodName.equals(node.getName().getIdentifier())) {
+                    this.closePresent = true;
+                    return DO_NOT_VISIT_SUBTREE;
+                }
+            }
+            return VISIT_SUBTREE;
+        }
+
+        @Override
+        public boolean visit(SimpleName node) {
+            if (isSameLocalVariable(node, cursorSimpleName)) {
+                this.lastCursorUse = node;
+            }
+            return VISIT_SUBTREE;
+        }
+
+        @Override
+        public boolean visit(Assignment node) {
+            if (isSameLocalVariable(node.getLeftHandSide(), cursorSimpleName)) {
+                return DO_NOT_VISIT_SUBTREE;
+            }
+            return VISIT_SUBTREE;
+        }
+    }
+
+    /*
+     * This visitor selects a partial part of the block to make the visit I.e.,
+     * it will only analyze the visitor from the variable assignment until the
+     * next assignment or end of the block startNode is a Assignment or
+     * VariableDeclarationFragment
+     */
+    private class VisitorDecorator extends ASTVisitor {
+        private ASTVisitor visitor;
+        private SimpleName cursorSimpleName;
+        private ASTVisitor specialVisitor;
+        private ASTNode startNode;
+
+        private class NopVisitor extends ASTVisitor {
+        }
+
+        VisitorDecorator(ASTNode startNode, SimpleName cursorSimpleName, ASTVisitor specialVisitor) {
+            this.cursorSimpleName = cursorSimpleName;
+            this.specialVisitor = specialVisitor;
+            this.startNode = startNode;
+            this.visitor = new NopVisitor();
+        }
+
+        @Override
+        public boolean visit(Assignment node) {
+            if (node.equals(startNode)) {
+                visitor = specialVisitor;
+            } else if (visitor != null && isSameLocalVariable(node.getLeftHandSide(), cursorSimpleName)) {
+                visitor = new NopVisitor();
+            }
+            return visitor.visit(node);
+        }
+
+        @Override
+        public boolean visit(VariableDeclarationFragment node) {
+            if (node.equals(startNode)) {
+                visitor = specialVisitor;
+            }
+            return visitor.visit(node);
+        }
+
+        @Override
+        public boolean visit(SimpleName node) {
+            return visitor.visit(node);
+        }
+
+        @Override
+        public boolean visit(MethodInvocation node) {
+            return visitor.visit(node);
+        }
+    }
+}