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/*
* Copyright (C) 2012 The Android Open Source Project
*
* Licensed under the Eclipse Public License, Version 1.0 (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.eclipse.org/org/documents/epl-v10.php
*
* 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 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.Issue;
import com.android.tools.lint.detector.api.JavaContext;
import com.android.tools.lint.detector.api.Scope;
import com.android.tools.lint.detector.api.Severity;
import com.android.tools.lint.detector.api.Speed;
import java.io.File;
import java.util.Collections;
import java.util.List;
import lombok.ast.AstVisitor;
import lombok.ast.Expression;
import lombok.ast.ForwardingAstVisitor;
import lombok.ast.IntegralLiteral;
import lombok.ast.MethodDeclaration;
import lombok.ast.MethodInvocation;
import lombok.ast.Node;
import lombok.ast.Return;
import lombok.ast.StrictListAccessor;
/** Detector looking for Toast.makeText() without a corresponding show() call */
public class ToastDetector extends Detector implements Detector.JavaScanner {
/** The main issue discovered by this detector */
public static final Issue ISSUE = Issue.create(
"ShowToast", //$NON-NLS-1$
"Looks for code creating a Toast but forgetting to call show() on it",
"Toast.makeText() creates a Toast but does *not* show it. You must call " +
"show() on the resulting object to actually make the Toast appear.",
Category.CORRECTNESS,
6,
Severity.WARNING,
ToastDetector.class,
Scope.JAVA_FILE_SCOPE);
/** Constructs a new {@link ToastDetector} check */
public ToastDetector() {
}
@Override
public boolean appliesTo(Context context, File file) {
return true;
}
@Override
public Speed getSpeed() {
return Speed.NORMAL;
}
// ---- Implements JavaScanner ----
@Override
public List<String> getApplicableMethodNames() {
return Collections.singletonList("makeText"); //$NON-NLS-1$
}
private MethodDeclaration findSurroundingMethod(Node scope) {
while (scope != null) {
Class<? extends Node> type = scope.getClass();
// The Lombok AST uses a flat hierarchy of node type implementation classes
// so no need to do instanceof stuff here.
if (type == MethodDeclaration.class) {
return (MethodDeclaration) scope;
}
scope = scope.getParent();
}
return null;
}
@Override
public void visitMethod(JavaContext context, AstVisitor visitor, MethodInvocation node) {
assert node.astName().astValue().equals("makeText");
if (node.astOperand() == null) {
// "makeText()" in the code with no operand
return;
}
String operand = node.astOperand().toString();
if (!(operand.equals("Toast") || operand.endsWith(".Toast"))) {
return;
}
// Make sure you pass the right kind of duration: it's not a delay, it's
// LENGTH_SHORT or LENGTH_LONG
// (see http://code.google.com/p/android/issues/detail?id=3655)
StrictListAccessor<Expression, MethodInvocation> args = node.astArguments();
if (args.size() == 3) {
Expression duration = args.last();
if (duration instanceof IntegralLiteral) {
context.report(ISSUE, context.getLocation(duration),
"Expected duration Toast.LENGTH_SHORT or Toast.LENGTH_LONG, a custom " +
"duration value is not supported",
null);
}
}
MethodDeclaration method = findSurroundingMethod(node.getParent());
if (method == null) {
return;
}
ShowFinder finder = new ShowFinder(node);
method.accept(finder);
if (!finder.isShowCalled()) {
context.report(ISSUE, method, context.getLocation(node),
"Toast created but not shown: did you forget to call show() ?", null);
}
}
private class ShowFinder extends ForwardingAstVisitor {
/** Whether we've found the show method */
private boolean mFound;
/** The target makeText call */
private MethodInvocation mTarget;
/** Whether we've seen the target makeText node yet */
private boolean mSeenTarget;
private ShowFinder(MethodInvocation target) {
mTarget = target;
}
@Override
public boolean visitMethodInvocation(MethodInvocation node) {
if (node == mTarget) {
mSeenTarget = true;
} else if ((mSeenTarget || node.astOperand() == mTarget)
&& "show".equals(node.astName().astValue())) { //$NON-NLS-1$
// TODO: Do more flow analysis to see whether we're really calling show
// on the right type of object?
mFound = true;
}
return true;
}
@Override
public boolean visitReturn(Return node) {
if (node.astValue() == mTarget) {
// If you just do "return Toast.makeText(...) don't warn
mFound = true;
}
return super.visitReturn(node);
}
boolean isShowCalled() {
return mFound;
}
}
}
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