lint/libs/lint-checks/src/main/java/com/android/tools/lint/checks/WrongCallDetector.java

/*
 * 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.CLASS_VIEW;
import static com.android.tools.lint.checks.JavaPerformanceDetector.ON_DRAW;
import static com.android.tools.lint.checks.JavaPerformanceDetector.ON_LAYOUT;
import static com.android.tools.lint.checks.JavaPerformanceDetector.ON_MEASURE;
import static com.android.tools.lint.detector.api.Lint.getMethodName;

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.LintFix;
import com.android.tools.lint.detector.api.Scope;
import com.android.tools.lint.detector.api.Severity;
import com.android.tools.lint.detector.api.SourceCodeScanner;
import com.intellij.psi.PsiMethod;
import java.util.Arrays;
import java.util.List;
import org.jetbrains.uast.UCallExpression;
import org.jetbrains.uast.UExpression;
import org.jetbrains.uast.UMethod;
import org.jetbrains.uast.USuperExpression;
import org.jetbrains.uast.UastUtils;

/** Checks for cases where the wrong call is being made */
public class WrongCallDetector extends Detector implements SourceCodeScanner {
    /** Calling the wrong method */
    public static final Issue ISSUE =
            Issue.create(
                            "WrongCall",
                            "Using wrong draw/layout method",
                            "Custom views typically need to call `measure()` on their children, not `onMeasure`. "
                                    + "Ditto for onDraw, onLayout, etc.",
                            Category.CORRECTNESS,
                            6,
                            Severity.ERROR,
                            new Implementation(WrongCallDetector.class, Scope.JAVA_FILE_SCOPE))
                    .setAndroidSpecific(true);

    /** Constructs a new {@link WrongCallDetector} */
    public WrongCallDetector() {}

    // ---- implements SourceCodeScanner ----

    @Override
    @Nullable
    public List<String> getApplicableMethodNames() {
        return Arrays.asList(ON_DRAW, ON_MEASURE, ON_LAYOUT);
    }

    @Override
    public void visitMethodCall(
            @NonNull JavaContext context,
            @NonNull UCallExpression node,
            @NonNull PsiMethod calledMethod) {
        // Call is only allowed if it is both only called on the super class (invoke special)
        // as well as within the same overriding method (e.g. you can't call super.onLayout
        // from the onMeasure method)
        UExpression operand = node.getReceiver();
        if (!(operand instanceof USuperExpression)) {
            report(context, node, calledMethod);
            return;
        }

        PsiMethod method = UastUtils.getParentOfType(node, UMethod.class, true);
        if (method != null) {
            String callName = getMethodName(node);
            if (callName != null && !callName.equals(method.getName())) {
                report(context, node, calledMethod);
            }
        }
    }

    private static void report(
            @NonNull JavaContext context,
            @NonNull UCallExpression node,
            @NonNull PsiMethod method) {
        // Make sure the call is on a view
        if (!context.getEvaluator().isMemberInSubClassOf(method, CLASS_VIEW, false)) {
            return;
        }

        String name = method.getName();
        String suggestion = Character.toLowerCase(name.charAt(2)) + name.substring(3);
        String message =
                String.format(
                        "Suspicious method call; should probably call \"`%1$s`\" rather than \"`%2$s`\"",
                        suggestion, name);
        LintFix fix =
                LintFix.create()
                        .name("Replace call with " + suggestion + "()")
                        .replace()
                        .text(name)
                        .with(suggestion)
                        .build();
        context.report(ISSUE, node, context.getNameLocation(node), message, fix);
    }
}