com.android.tools.lint.checks.CutPasteDetector Maven / Gradle / Ivy
/*
* Copyright (C) 2012 The Android Open Source Project
*
* 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.android.tools.lint.checks;
import static com.android.SdkConstants.RESOURCE_CLZ_ID;
import com.android.annotations.NonNull;
import com.android.annotations.Nullable;
import com.android.tools.lint.detector.api.Category;
import com.android.tools.lint.detector.api.Context;
import com.android.tools.lint.detector.api.Detector;
import com.android.tools.lint.detector.api.Implementation;
import com.android.tools.lint.detector.api.Issue;
import com.android.tools.lint.detector.api.JavaContext;
import com.android.tools.lint.detector.api.Location;
import com.android.tools.lint.detector.api.Scope;
import com.android.tools.lint.detector.api.Severity;
import com.google.common.collect.Maps;
import java.io.File;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import lombok.ast.ArrayAccess;
import lombok.ast.AstVisitor;
import lombok.ast.BinaryExpression;
import lombok.ast.Cast;
import lombok.ast.Expression;
import lombok.ast.ForwardingAstVisitor;
import lombok.ast.If;
import lombok.ast.MethodInvocation;
import lombok.ast.Node;
import lombok.ast.Select;
import lombok.ast.Statement;
import lombok.ast.VariableDefinitionEntry;
import lombok.ast.VariableReference;
/**
* Detector looking for cut & paste issues
*/
public class CutPasteDetector extends Detector implements Detector.JavaScanner {
/** The main issue discovered by this detector */
public static final Issue ISSUE = Issue.create(
"CutPasteId", //$NON-NLS-1$
"Likely cut & paste mistakes",
"This lint check looks for cases where you have cut & pasted calls to " +
"`findViewById` but have forgotten to update the R.id field. It's possible " +
"that your code is simply (redundantly) looking up the field repeatedly, " +
"but lint cannot distinguish that from a case where you for example want to " +
"initialize fields `prev` and `next` and you cut & pasted `findViewById(R.id.prev)` " +
"and forgot to update the second initialization to `R.id.next`.",
Category.CORRECTNESS,
6,
Severity.WARNING,
new Implementation(
CutPasteDetector.class,
Scope.JAVA_FILE_SCOPE));
private Node mLastMethod;
private Map mIds;
private Map mLhs;
private Map mCallOperands;
/** Constructs a new {@link CutPasteDetector} check */
public CutPasteDetector() {
}
@Override
public boolean appliesTo(@NonNull Context context, @NonNull File file) {
return true;
}
// ---- Implements JavaScanner ----
@Override
public List getApplicableMethodNames() {
return Collections.singletonList("findViewById"); //$NON-NLS-1$
}
@Override
public void visitMethod(@NonNull JavaContext context, @Nullable AstVisitor visitor,
@NonNull MethodInvocation call) {
String lhs = getLhs(call);
if (lhs == null) {
return;
}
Node method = JavaContext.findSurroundingMethod(call);
if (method == null) {
return;
} else if (method != mLastMethod) {
mIds = Maps.newHashMap();
mLhs = Maps.newHashMap();
mCallOperands = Maps.newHashMap();
mLastMethod = method;
}
String callOperand = call.astOperand() != null ? call.astOperand().toString() : "";
Expression first = call.astArguments().first();
if (first instanceof Select) {
Select select = (Select) first;
String id = select.astIdentifier().astValue();
Expression operand = select.astOperand();
if (operand instanceof Select) {
Select type = (Select) operand;
if (type.astIdentifier().astValue().equals(RESOURCE_CLZ_ID)) {
if (mIds.containsKey(id)) {
if (lhs.equals(mLhs.get(id))) {
return;
}
if (!callOperand.equals(mCallOperands.get(id))) {
return;
}
MethodInvocation earlierCall = mIds.get(id);
if (!isReachableFrom(method, earlierCall, call)) {
return;
}
Location location = context.getLocation(call);
Location secondary = context.getLocation(earlierCall);
secondary.setMessage("First usage here");
location.setSecondary(secondary);
context.report(ISSUE, call, location, String.format(
"The id `%1$s` has already been looked up in this method; possible " +
"cut & paste error?", first.toString()));
} else {
mIds.put(id, call);
mLhs.put(id, lhs);
mCallOperands.put(id, callOperand);
}
}
}
}
}
@Nullable
private static String getLhs(@NonNull MethodInvocation call) {
Node parent = call.getParent();
if (parent instanceof Cast) {
parent = parent.getParent();
}
if (parent instanceof VariableDefinitionEntry) {
VariableDefinitionEntry vde = (VariableDefinitionEntry) parent;
return vde.astName().astValue();
} else if (parent instanceof BinaryExpression) {
BinaryExpression be = (BinaryExpression) parent;
Expression left = be.astLeft();
if (left instanceof VariableReference || left instanceof Select) {
return be.astLeft().toString();
} else if (left instanceof ArrayAccess) {
ArrayAccess aa = (ArrayAccess) left;
return aa.astOperand().toString();
}
}
return null;
}
private static boolean isReachableFrom(
@NonNull Node method,
@NonNull MethodInvocation from,
@NonNull MethodInvocation to) {
ReachableVisitor visitor = new ReachableVisitor(from, to);
method.accept(visitor);
return visitor.isReachable();
}
private static class ReachableVisitor extends ForwardingAstVisitor {
@NonNull private final MethodInvocation mFrom;
@NonNull private final MethodInvocation mTo;
private boolean mReachable;
private boolean mSeenEnd;
public ReachableVisitor(@NonNull MethodInvocation from, @NonNull MethodInvocation to) {
mFrom = from;
mTo = to;
}
boolean isReachable() {
return mReachable;
}
@Override
public boolean visitMethodInvocation(MethodInvocation node) {
if (node == mFrom) {
mReachable = true;
} else if (node == mTo) {
mSeenEnd = true;
}
return super.visitMethodInvocation(node);
}
@Override
public boolean visitIf(If node) {
Expression condition = node.astCondition();
Statement body = node.astStatement();
Statement elseBody = node.astElseStatement();
if (condition != null) {
condition.accept(this);
}
if (body != null) {
boolean wasReachable = mReachable;
body.accept(this);
mReachable = wasReachable;
}
if (elseBody != null) {
boolean wasReachable = mReachable;
elseBody.accept(this);
mReachable = wasReachable;
}
endVisit(node);
return false;
}
@Override
public boolean visitNode(Node node) {
return mSeenEnd;
}
}
}