Add ADB transport skeleton

This adds the AIDL definition for ADB transports. For instance USB is
one type of ADB transport and the only one supported now.

Bug: 63820489
Test: make
Change-Id: Id422a814567021ab4b1097c2792a95c42bfccf74

Android.bp

@@ -151,6 +151,7 @@ java_defaults {
         "core/java/android/content/pm/permission/IRuntimePermissionPresenter.aidl",
         "core/java/android/database/IContentObserver.aidl",
         "core/java/android/debug/IAdbManager.aidl",
+        "core/java/android/debug/IAdbTransport.aidl",
         ":libcamera_client_aidl",
         ":libcamera_client_framework_aidl",
         "core/java/android/hardware/IConsumerIrService.aidl",

core/java/android/debug/AdbManagerInternal.java

@@ -23,4 +23,17 @@ package android.debug;
  * @hide Only should be called from the system server.
  */
 public abstract class AdbManagerInternal {
+    /**
+     * Registers a ADB transport mechanism.
+     *
+     * @param transport ADB transport interface to register
+     */
+    public abstract void registerTransport(IAdbTransport transport);
+
+    /**
+     * Unregisters a previously registered ADB transport mechanism.
+     *
+     * @param transport previously-added ADB transport interface to be removed
+     */
+    public abstract void unregisterTransport(IAdbTransport transport);
 }

core/java/android/debug/IAdbTransport.aidl

@@ -0,0 +1,21 @@
+/*
+ * 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 android.debug;
+
+/** @hide */
+interface IAdbTransport {
+}

services/core/java/com/android/server/adb/AdbService.java

@@ -18,7 +18,10 @@ package com.android.server.adb;
 import android.content.Context;
 import android.debug.AdbManagerInternal;
 import android.debug.IAdbManager;
+import android.debug.IAdbTransport;
 import android.os.Binder;
+import android.os.IBinder;
+import android.util.ArrayMap;
 
 import com.android.internal.util.DumpUtils;
 import com.android.internal.util.IndentingPrintWriter;
@@ -51,11 +54,21 @@ public class AdbService extends IAdbManager.Stub {
     }
 
     private class AdbManagerInternalImpl extends AdbManagerInternal {
+        @Override
+        public void registerTransport(IAdbTransport transport) {
+            mTransports.put(transport.asBinder(), transport);
+        }
+
+        @Override
+        public void unregisterTransport(IAdbTransport transport) {
+            mTransports.remove(transport.asBinder());
+        }
     }
 
     private static final String TAG = "AdbService";
 
     private final Context mContext;
+    private final ArrayMap<IBinder, IAdbTransport> mTransports = new ArrayMap<>();
 
     private AdbService(Context context) {
         mContext = context;
@@ -73,8 +86,8 @@ public class AdbService extends IAdbManager.Stub {
             if (args == null || args.length == 0 || "-a".equals(args[0])) {
                 pw.println("ADB Manager State:");
                 pw.increaseIndent();
-                pw.println("None");
-                // TODO: flesh out with status.
+                pw.print("Number of registered transports: ");
+                pw.println(mTransports.size());
             } else {
                 pw.println("Dump current ADB state");
                 pw.println("  No commands available");