Pull authentication UX code out of JniInterface

remoting/android/java/src/org/chromium/chromoting/SessionAuthenticator.java

+// Copyright 2015 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.chromoting;
+
+import android.app.Activity;
+import android.app.AlertDialog;
+import android.content.DialogInterface;
+import android.content.Intent;
+import android.content.SharedPreferences;
+import android.os.Build;
+import android.view.KeyEvent;
+import android.view.View;
+import android.widget.CheckBox;
+import android.widget.TextView;
+import android.widget.Toast;
+
+import org.chromium.chromoting.jni.JniInterface;
+
+/**
+ * This class performs the user-interaction needed to authenticate the session connection. This
+ * includes showing the PIN prompt and requesting tokens for third-party authentication.
+ */
+public class SessionAuthenticator {
+    /**
+     * Application context used for getting user preferences, displaying UI, and fetching
+     * third-party tokens.
+     */
+    private Chromoting mApplicationContext;
+
+    /** Provides the tokenUrlPatterns for this host during fetchThirdPartyTokens(). */
+    private HostInfo mHost;
+
+    /** Object for fetching OAuth2 access tokens from third party authorization servers. */
+    private ThirdPartyTokenFetcher mTokenFetcher;
+
+    public SessionAuthenticator(Chromoting context, HostInfo host) {
+        mApplicationContext = context;
+        mHost = host;
+    }
+
+    public void displayAuthenticationPrompt(boolean pairingSupported) {
+        AlertDialog.Builder pinPrompt = new AlertDialog.Builder(mApplicationContext);
+        pinPrompt.setTitle(mApplicationContext.getString(R.string.title_authenticate));
+        pinPrompt.setMessage(mApplicationContext.getString(R.string.pin_message_android));
+        pinPrompt.setIcon(android.R.drawable.ic_lock_lock);
+
+        final View pinEntry =
+                mApplicationContext.getLayoutInflater().inflate(R.layout.pin_dialog, null);
+        pinPrompt.setView(pinEntry);
+
+        final TextView pinTextView = (TextView) pinEntry.findViewById(R.id.pin_dialog_text);
+        final CheckBox pinCheckBox = (CheckBox) pinEntry.findViewById(R.id.pin_dialog_check);
+
+        if (!pairingSupported) {
+            pinCheckBox.setChecked(false);
+            pinCheckBox.setVisibility(View.GONE);
+        }
+
+        pinPrompt.setPositiveButton(
+                R.string.connect_button, new DialogInterface.OnClickListener() {
+                    @Override
+                    public void onClick(DialogInterface dialog, int which) {
+                        if (JniInterface.isConnected()) {
+                            JniInterface.handleAuthenticationResponse(
+                                    String.valueOf(pinTextView.getText()),
+                                    pinCheckBox.isChecked(), Build.MODEL);
+                        } else {
+                            String message =
+                                    mApplicationContext.getString(R.string.error_network_error);
+                            Toast.makeText(mApplicationContext, message, Toast.LENGTH_LONG).show();
+                        }
+                    }
+                });
+
+        pinPrompt.setNegativeButton(
+                R.string.cancel, new DialogInterface.OnClickListener() {
+                    @Override
+                    public void onClick(DialogInterface dialog, int which) {
+                        JniInterface.disconnectFromHost();
+                    }
+                });
+
+        final AlertDialog pinDialog = pinPrompt.create();
+
+        pinTextView.setOnEditorActionListener(
+                new TextView.OnEditorActionListener() {
+                    @Override
+                    public boolean onEditorAction(TextView v, int actionId, KeyEvent event) {
+                        // The user pressed enter on the keypad (equivalent to the connect button).
+                        pinDialog.getButton(AlertDialog.BUTTON_POSITIVE).performClick();
+                        pinDialog.dismiss();
+                        return true;
+                    }
+                });
+
+        pinDialog.setOnCancelListener(
+                new DialogInterface.OnCancelListener() {
+                    @Override
+                    public void onCancel(DialogInterface dialog) {
+                        // The user backed out of the dialog (equivalent to the cancel button).
+                        pinDialog.getButton(AlertDialog.BUTTON_NEGATIVE).performClick();
+                    }
+                });
+
+        pinDialog.show();
+    }
+
+    /** Saves newly-received pairing credentials to permanent storage. */
+    public void commitPairingCredentials(String host, String id, String secret) {
+        // Empty |id| indicates that pairing needs to be removed.
+        if (id.isEmpty()) {
+            mApplicationContext.getPreferences(Activity.MODE_PRIVATE).edit()
+                    .remove(host + "_id")
+                    .remove(host + "_secret")
+                    .apply();
+        } else {
+            mApplicationContext.getPreferences(Activity.MODE_PRIVATE).edit()
+                    .putString(host + "_id", id)
+                    .putString(host + "_secret", secret)
+                    .apply();
+        }
+    }
+
+    public void fetchThirdPartyToken(String tokenUrl, String clientId, String scope) {
+        assert mTokenFetcher == null;
+
+        ThirdPartyTokenFetcher.Callback callback = new ThirdPartyTokenFetcher.Callback() {
+            @Override
+            public void onTokenFetched(String code, String accessToken) {
+                // The native client sends the OAuth authorization code to the host as the token so
+                // that the host can obtain the shared secret from the third party authorization
+                // server.
+                String token = code;
+
+                // The native client uses the OAuth access token as the shared secret to
+                // authenticate itself with the host using spake.
+                String sharedSecret = accessToken;
+
+                JniInterface.onThirdPartyTokenFetched(token, sharedSecret);
+            }
+        };
+        mTokenFetcher = new ThirdPartyTokenFetcher(mApplicationContext, mHost.getTokenUrlPatterns(),
+                callback);
+        mTokenFetcher.fetchToken(tokenUrl, clientId, scope);
+    }
+
+    public void onNewIntent(Intent intent) {
+        if (mTokenFetcher != null) {
+            if (mTokenFetcher.handleTokenFetched(intent)) {
+                mTokenFetcher = null;
+            }
+        }
+    }
+
+    /** Returns the pairing ID for the given host, or an empty string if not set. */
+    public String getPairingId(String hostId) {
+        SharedPreferences prefs = mApplicationContext.getPreferences(Activity.MODE_PRIVATE);
+        return prefs.getString(hostId + "_id", "");
+    }
+
+    /** Returns the pairing secret for the given host, or an empty string if not set. */
+    public String getPairingSecret(String hostId) {
+        SharedPreferences prefs = mApplicationContext.getPreferences(Activity.MODE_PRIVATE);
+        return prefs.getString(hostId + "_secret", "");
+    }
+}