lint/libs/lint-checks/src/main/java/com/android/tools/lint/checks/C2dmDetector.kt

/*
 * Copyright (C) 2018 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 com.android.SdkConstants.ANDROID_URI
import com.android.SdkConstants.ATTR_NAME
import com.android.SdkConstants.TAG_ACTION
import com.android.SdkConstants.TAG_INTENT_FILTER
import com.android.SdkConstants.TAG_RECEIVER
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.Scope
import com.android.tools.lint.detector.api.Severity
import com.android.tools.lint.detector.api.XmlContext
import com.android.tools.lint.detector.api.XmlScanner
import com.android.utils.XmlUtils.getFirstSubTagByName
import com.android.utils.XmlUtils.getNextTagByName
import org.w3c.dom.Element

/** Flags usages of C2DM, which as of P no longer works */
class C2dmDetector : Detector(), XmlScanner {

    override fun getApplicableElements(): Collection<String>? {
        return listOf(TAG_RECEIVER)
    }

    override fun visitElement(context: XmlContext, element: Element) {
        val attribute = element.getAttributeNodeNS(ANDROID_URI, ATTR_NAME) ?: return
        val receiverName = attribute.value
        if (receiverName != "com.google.android.c2dm.C2DMBroadcastReceiver" &&
            receiverName != "com.google.android.gcm.GCMBroadcastReceiver"
        ) {
            return
        }

        var haveReceive = false
        var haveRegistration = false
        var intentFilter = getFirstSubTagByName(element, TAG_INTENT_FILTER)
        while (intentFilter != null) {
            var action = getFirstSubTagByName(intentFilter, TAG_ACTION)
            while (action != null) {
                val actionName = action.getAttributeNS(ANDROID_URI, ATTR_NAME)
                if (actionName == "com.google.android.c2dm.intent.RECEIVE") {
                    haveReceive = true
                } else if (actionName == "com.google.android.c2dm.intent.REGISTRATION") {
                    haveRegistration = true
                }
                action = getNextTagByName(action, TAG_ACTION)
            }

            intentFilter = getNextTagByName(intentFilter, TAG_INTENT_FILTER)
        }

        if (haveReceive && haveRegistration) {
            val message = "The C2DM library does not work on Android P or newer devices; " +
                    "you should migrate to Firebase Cloud Messaging to ensure reliable " +
                    "message delivery."
            context.report(ISSUE, attribute, context.getValueLocation(attribute), message)
        }
    }

    companion object {
        private val IMPLEMENTATION = Implementation(
            C2dmDetector::class.java,
            Scope.MANIFEST_SCOPE
        )

        @JvmField
        val ISSUE = Issue.create(
            id = "UsingC2DM",
            briefDescription = "Using C2DM",
            explanation = """The C2DM library does not work on Android P or newer devices; \
            you should migrate to Firebase Cloud Messaging to ensure reliable message delivery.""",
            moreInfo = "https://developers.google.com/cloud-messaging/c2dm",
            category = Category.SECURITY,
            priority = 8,
            severity = Severity.ERROR,
            implementation = IMPLEMENTATION
        )
    }
}