components/cronet/android/java/src/org/chromium/net/impl/CronetLoggerFactory.java

// Copyright 2022 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

package org.chromium.net.impl;

import android.content.Context;
import android.os.Build;
import android.util.Log; // TODO(crbug/1394709): use org.chromium.base.Log instead

import androidx.annotation.Nullable;
import androidx.annotation.VisibleForTesting;

import org.chromium.net.impl.CronetLogger.CronetSource;
import org.chromium.net.telemetry.CronetLoggerImpl;

/** Takes care of instantiating the correct CronetLogger. */
public final class CronetLoggerFactory {
    private static final String TAG = CronetLoggerFactory.class.getSimpleName();
    private static final int SAMPLE_RATE_PER_SECOND = 1;

    private CronetLoggerFactory() {}

    private static final CronetLogger sDefaultLogger = new NoOpLogger();
    private static CronetLogger sTestingLogger;

    /**
     * Bypasses CronetLoggerFactory logic and always creates a NoOpLogger.
     * To be used only as a kill-switch for logging.
     * @return a NoOpLogger instance.
     */
    public static CronetLogger createNoOpLogger() {
        return sDefaultLogger;
    }

    /** @return The correct CronetLogger to be used for logging. */
    public static CronetLogger createLogger(Context ctx, CronetSource source) {
        if (sTestingLogger != null) return sTestingLogger;

        // The CronetLoggerImpl only works from apiLevel 30
        if (!CronetManifest.isAppOptedInForTelemetry(ctx, source)
                || Build.VERSION.SDK_INT < Build.VERSION_CODES.R) {
            return sDefaultLogger;
        }

        try {
            return new CronetLoggerImpl(SAMPLE_RATE_PER_SECOND);
        } catch (Exception e) {
            // Pass - since we dont want any failure, catch any exception that might arise.
            Log.e(TAG, "Exception creating an instance of CronetLoggerImpl", e);
        }
        return sDefaultLogger;
    }

    @VisibleForTesting
    public static void setLoggerForTesting(@Nullable CronetLogger testingLogger) {
        sTestingLogger = testingLogger;
    }

    /**
     * Utility class to safely use a custom CronetLogger for the duration of a test.
     * To be used within a try-with-resources statement within the test.
     */
    public static class SwapLoggerForTesting implements AutoCloseable {
        /**
         * Forces {@code CronetLoggerFactory#createLogger} to return @param testLogger instead of
         * what it would have normally returned.
         */
        public SwapLoggerForTesting(CronetLogger testLogger) {
            CronetLoggerFactory.setLoggerForTesting(testLogger);
        }

        /** Restores CronetLoggerFactory to its original state. */
        @Override
        public void close() {
            CronetLoggerFactory.setLoggerForTesting(null);
        }
    }
}