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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 static com.android.tools.lint.detector.api.LintUtils.skipParentheses;
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.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 com.intellij.psi.JavaElementVisitor;
import com.intellij.psi.PsiArrayAccessExpression;
import com.intellij.psi.PsiAssignmentExpression;
import com.intellij.psi.PsiBinaryExpression;
import com.intellij.psi.PsiBreakStatement;
import com.intellij.psi.PsiContinueStatement;
import com.intellij.psi.PsiElement;
import com.intellij.psi.PsiExpression;
import com.intellij.psi.PsiIfStatement;
import com.intellij.psi.PsiJavaToken;
import com.intellij.psi.PsiLocalVariable;
import com.intellij.psi.PsiLoopStatement;
import com.intellij.psi.PsiMethod;
import com.intellij.psi.PsiMethodCallExpression;
import com.intellij.psi.PsiReference;
import com.intellij.psi.PsiReferenceExpression;
import com.intellij.psi.PsiReturnStatement;
import com.intellij.psi.PsiStatement;
import com.intellij.psi.PsiTypeCastExpression;
import com.intellij.psi.PsiWhiteSpace;
import com.intellij.psi.util.PsiTreeUtil;
import java.util.Collections;
import java.util.List;
import java.util.Map;
/**
* Detector looking for cut & paste issues
*/
public class CutPasteDetector extends Detector implements Detector.JavaPsiScanner {
/** 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 PsiMethod mLastMethod;
private Map mIds;
private Map mLhs;
private Map mCallOperands;
/** Constructs a new {@link CutPasteDetector} check */
public CutPasteDetector() {
}
// ---- Implements JavaScanner ----
@Override
public List getApplicableMethodNames() {
return Collections.singletonList("findViewById"); //$NON-NLS-1$
}
@Override
public void visitMethod(@NonNull JavaContext context, @Nullable JavaElementVisitor visitor,
@NonNull PsiMethodCallExpression call, @NonNull PsiMethod calledMethod) {
String lhs = getLhs(call);
if (lhs == null) {
return;
}
PsiMethod method = PsiTreeUtil.getParentOfType(call, PsiMethod.class, false);
if (method == null) {
return; // prevent doing the same work for multiple findViewById calls in same method
} else if (method != mLastMethod) {
mIds = Maps.newHashMap();
mLhs = Maps.newHashMap();
mCallOperands = Maps.newHashMap();
mLastMethod = method;
}
PsiReferenceExpression methodExpression = call.getMethodExpression();
String callOperand = methodExpression.getQualifier() != null
? methodExpression.getQualifier().getText() : "";
PsiExpression[] arguments = call.getArgumentList().getExpressions();
if (arguments.length == 0) {
return;
}
PsiExpression first = arguments[0];
if (first instanceof PsiReferenceExpression) {
PsiReferenceExpression psiReferenceExpression = (PsiReferenceExpression) first;
String id = psiReferenceExpression.getReferenceName();
PsiElement operand = psiReferenceExpression.getQualifier();
if (operand instanceof PsiReferenceExpression) {
PsiReferenceExpression type = (PsiReferenceExpression) operand;
if (RESOURCE_CLZ_ID.equals(type.getReferenceName())) {
if (mIds.containsKey(id)) {
if (lhs.equals(mLhs.get(id))) {
return;
}
if (!callOperand.equals(mCallOperands.get(id))) {
return;
}
PsiMethodCallExpression 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.getText()));
} else {
mIds.put(id, call);
mLhs.put(id, lhs);
mCallOperands.put(id, callOperand);
}
}
}
}
}
@Nullable
private static String getLhs(@NonNull PsiMethodCallExpression call) {
PsiElement parent = skipParentheses(call.getParent());
if (parent instanceof PsiTypeCastExpression) {
parent = parent.getParent();
}
if (parent instanceof PsiLocalVariable) {
return ((PsiLocalVariable)parent).getName();
} else if (parent instanceof PsiBinaryExpression) {
PsiBinaryExpression be = (PsiBinaryExpression) parent;
PsiExpression left = be.getLOperand();
if (left instanceof PsiReference) {
return left.getText();
} else if (left instanceof PsiArrayAccessExpression) {
PsiArrayAccessExpression aa = (PsiArrayAccessExpression) left;
return aa.getArrayExpression().getText();
}
} else if (parent instanceof PsiAssignmentExpression) {
PsiExpression left = ((PsiAssignmentExpression) parent).getLExpression();
if (left instanceof PsiReference) {
return left.getText();
} else if (left instanceof PsiArrayAccessExpression) {
PsiArrayAccessExpression aa = (PsiArrayAccessExpression) left;
return aa.getArrayExpression().getText();
}
}
return null;
}
static boolean isReachableFrom(
@NonNull PsiMethod method,
@NonNull PsiElement from,
@NonNull PsiElement to) {
PsiElement prev = from;
PsiElement curr = next(method, from, to, null);
//noinspection ConstantConditions
while (curr != null) {
if (containsElement(method, curr, to)) {
return true;
}
curr = next(method, curr, to, prev);
prev = curr;
}
return false;
}
@Nullable
static PsiElement next(
@NonNull PsiMethod method,
@NonNull PsiElement curr,
@NonNull PsiElement target,
@Nullable PsiElement prev) {
if (curr instanceof PsiMethod) {
return null;
}
PsiElement parent = curr.getParent();
if (curr instanceof PsiContinueStatement) {
PsiStatement continuedStatement = ((PsiContinueStatement) curr)
.findContinuedStatement();
if (continuedStatement != null) {
if (containsElement(method, continuedStatement, target)) {
return target;
}
return next(method, continuedStatement, target, curr);
} else {
return next(method, parent, target, curr);
}
} else if (curr instanceof PsiBreakStatement) {
PsiStatement exitedStatement = ((PsiBreakStatement) curr).findExitedStatement();
if (exitedStatement != null) {
return next(method, exitedStatement, target, curr);
} else {
return next(method, parent, target, curr);
}
} else if (curr instanceof PsiReturnStatement) {
return null;
} else if (curr instanceof PsiLoopStatement && prev != null &&
containsElement(method, curr, prev)) {
// If we stepped *up* (from a last child nested in the loop) up to the loop
// itself, mark all children in the loop as reachable since we're iterating
if (containsElement(method, curr, target)) {
return target;
}
}
PsiElement sibling = curr.getNextSibling();
while (sibling instanceof PsiWhiteSpace || sibling instanceof PsiJavaToken) {
// Skip whitespaces and tokens such as PsiJavaToken.SEMICOLON etc
sibling = sibling.getNextSibling();
}
if (sibling == null) {
return next(method, parent, target, curr);
}
if (parent instanceof PsiIfStatement &&
curr == ((PsiIfStatement)parent).getThenBranch()) {
return next(method, parent, target, curr);
} else if (parent instanceof PsiLoopStatement) {
if (containsElement(method, parent, target)) {
return target;
}
}
return sibling;
}
private static boolean containsElement(@
NonNull PsiMethod method,
@NonNull PsiElement root,
@NonNull PsiElement element) {
//noinspection ConstantConditions
while (element != null && element != method) {
if (root.equals(element)) {
return true;
}
element = element.getParent();
}
return false;
}
}
