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;
+
+    /** Object for fetching OAuth2 access tokens from third party authorization servers. */
+    private ThirdPartyTokenFetcher mTokenFetcher;
+
+    public SessionAuthenticator(Chromoting context, HostInfo host) {
+        mApplicationContext = context;
+
+        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(context, host.getTokenUrlPatterns(), callback);

[Sergey Ulanov, 2015/03/16 19:56:09]

Does this need to be in the constructor? Can it be moved to
fetchThirdPartyToken()?

[Lambros, 2015/03/18 01:01:14]

Done.

[Lambros, 2015/03/18 01:01:14]

Done.

+    }
+
+    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;
+        mTokenFetcher.fetchToken(tokenUrl, clientId, scope);
+    }
+
+    public void handleTokenFetched(Intent intent) {

[Sergey Ulanov, 2015/03/16 19:56:09]

I think it would be better to call this method onNewIntent(). Otherwise it's
confusing because this call is ignored when mTokenFetcher is null. The new
intent may not be related to third-party auth.

[Lambros, 2015/03/18 01:01:14]

Done.

+        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", "");
+    }
+}