Refactor WebApkServiceConnectionManager.

chrome/android/webapk/libs/client/src/org/chromium/webapk/lib/client/WebApkIdentityServiceClient.java

Index: chrome/android/webapk/libs/client/src/org/chromium/webapk/lib/client/WebApkIdentityServiceClient.java
diff --git a/chrome/android/webapk/libs/client/src/org/chromium/webapk/lib/client/WebApkIdentityServiceClient.java b/chrome/android/webapk/libs/client/src/org/chromium/webapk/lib/client/WebApkIdentityServiceClient.java
new file mode 100644
index 0000000000000000000000000000000000000000..7b1d2026e1df446a2794e836b2ee4bd34c4cb983
--- /dev/null
+++ b/chrome/android/webapk/libs/client/src/org/chromium/webapk/lib/client/WebApkIdentityServiceClient.java
@@ -0,0 +1,148 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.webapk.lib.client;
+
+import android.content.Context;
+import android.content.pm.ApplicationInfo;
+import android.content.pm.PackageManager;
+import android.os.Bundle;
+import android.os.IBinder;
+import android.os.RemoteException;
+import android.text.TextUtils;
+import android.util.Log;
+
+import org.chromium.webapk.lib.common.WebApkMetaDataKeys;
+import org.chromium.webapk.lib.common.identity_service.IIdentityService;
+
+/**
+ * Provides APIs for browsers to communicate with WebAPK Identity services. Each WebAPK has its own
+ * "WebAPK Identity service".
+ */
+public class WebApkIdentityServiceClient {
+    /** Used to notify the consumer after checking whether the caller browser backs the WebAPK. */
+    public interface CheckBrowserBacksWebApkCallback {
+        void onChecked(boolean doesBrowserBackWebApk);
+    }
+
+    /**
+     * Before shell APK version 6, all WebAPKs are installed from browsers, and that browser is the
+     * runtime host and specified in the WebAPK's AndroidManifest.xml. In shell APK version 6, we
+     * introduced logic to allow user to choose runtime host browser for WebAPKs not bound to any
+     * browser, and for WebAPKs installed from browsers when the browser is subsequently
+     * uninstalled. However, the browser cannot track of WebAPKs which are backed by the browser
+     * because the browser is not notified if a user changes the runtime host of a WebAPK by
+     * clearing the WebAPK's data. Besides, the browser loses the knowledge of WebAPKs if a user
+     * clears the browser's data. Therefore, a browser doesn't know whether it is the runtime host
+     * of a WebAPK without asking the WebAPK. An Identity service is introduced in shell APK version
+     * 16 to allow browsers to query the runtime host of a WebAPK.
+     */
+    public static final int SHELL_APK_VERSION_SUPPORTING_SWITCH_RUNTIME_HOST = 6;
+
+    private static final String ACTION_WEBAPK_IDENTITY_SERVICE = "org.webapk.IDENTITY_SERVICE_API";
+    private static final String TAG = "cr_WebApkIdentityService";
+
+    private static WebApkIdentityServiceClient sInstance;
+
+    /** Manages connections between the browser application and WebAPK Identity services. */
+    private WebApkServiceConnectionManager mConnectionManager;
+
+    public static WebApkIdentityServiceClient getInstance() {
+        if (sInstance == null) {
+            sInstance = new WebApkIdentityServiceClient();
+        }
+        return sInstance;
+    }
+
+    private WebApkIdentityServiceClient() {
+        mConnectionManager = new WebApkServiceConnectionManager(
+                null /* category */, ACTION_WEBAPK_IDENTITY_SERVICE);
+    }
+
+    /**
+     * Checks whether a WebAPK is backed by the browser with {@link browserContext}.
+     * @param browserContext The browser context.
+     * @param webApkPackageName The package name of the WebAPK.
+     * @param callback The callback to be called after querying the runtime host is done.
+     */
+    public void checkBrowserBacksWebApkAsync(final Context browserContext,
+            final String webApkPackageName, final CheckBrowserBacksWebApkCallback callback) {
+        WebApkServiceConnectionManager.ConnectionCallback connectionCallback =
+                new WebApkServiceConnectionManager.ConnectionCallback() {
+                    @Override
+                    public void onConnected(IBinder service) {
+                        String browserPackageName = browserContext.getPackageName();
+                        if (service == null) {
+                            onGotWebApkRuntimeHost(browserPackageName,
+                                    maybeExtractRuntimeHostFromMetaData(
+                                            browserContext, webApkPackageName),
+                                    callback);
+                            return;
+                        }
+
+                        IIdentityService identityService =
+                                IIdentityService.Stub.asInterface(service);
+                        String runtimeHost = null;
+                        try {
+                            // The runtime host could be null if the WebAPK hasn't bound to any
+                            // browser yet.
+                            runtimeHost = identityService.getRuntimeHostBrowserPackageName();
+                        } catch (RemoteException e) {
+                            Log.w(TAG, "Failed to get runtime host from the Identity service.");
+                        }
+                        onGotWebApkRuntimeHost(browserPackageName, runtimeHost, callback);
+                    }
+                };
+        mConnectionManager.connect(browserContext, webApkPackageName, connectionCallback);
+    }
+
+    /**
+     * Called after fetching the WebAPK's backing browser.
+     * @param browserPackageName The browser's package name.
+     * @param webApkBackingBrowserPackageName The package name of the WebAPK's backing browser.
+     * @param callback The callback to notify whether {@link browserPackageName} backs the WebAPK.
+     */
+    private static void onGotWebApkRuntimeHost(String browserPackageName,
+            String webApkBackingBrowserPackageName, CheckBrowserBacksWebApkCallback callback) {
+        callback.onChecked(TextUtils.equals(webApkBackingBrowserPackageName, browserPackageName));
+    }
+
+    /**
+     * Extracts the backing browser from the WebAPK's meta data.
+     * See {@link WebApkIdentityServiceClient#SHELL_APK_VERSION_SUPPORTING_SWITCH_RUNTIME_HOST} for
+     * more details.
+     */
+    private static String maybeExtractRuntimeHostFromMetaData(
+            Context context, String webApkPackageName) {
+        Bundle metadata = readMetaData(context, webApkPackageName);
+        if (metadata == null
+                || metadata.getInt(WebApkMetaDataKeys.SHELL_APK_VERSION)
+                        >= SHELL_APK_VERSION_SUPPORTING_SWITCH_RUNTIME_HOST) {
+            // The backing browser in the WebAPK's meta data may not be the one which actually backs
+            // the WebAPK. The user may have switched the backing browser.
+            return null;
+        }
+
+        return metadata.getString(WebApkMetaDataKeys.RUNTIME_HOST);
+    }
+
+    /** Returns the <meta-data> in the Android Manifest of the given package name. */
+    private static Bundle readMetaData(Context context, String packageName) {
+        ApplicationInfo ai = null;
+        try {
+            ai = context.getPackageManager().getApplicationInfo(
+                    packageName, PackageManager.GET_META_DATA);
+        } catch (PackageManager.NameNotFoundException e) {
+            return null;
+        }
+        return ai.metaData;
+    }
+
+    /** Disconnects all the connections to WebAPK Identity services. */
+    public static void disconnectAll(Context appContext) {
+        if (sInstance == null) return;
+
+        sInstance.mConnectionManager.disconnectAll(appContext);
+    }
+}