Pull authentication UX code out of JniInterface

UX code does not belong in the JniInterface layer. This is a first step
towards refactoring the JNI layer away from static methods, into a
separate object whose lifetime is controlled by Java, which can be
mocked for testing.

Review URL: https://codereview.chromium.org/981783003

Cr-Commit-Position: refs/heads/master@{#321187}

4 files changed, 207 insertions, 133 deletions

diff --git a/remoting/android/java/src/org/chromium/chromoting/Chromoting.java b/remoting/android/java/src/org/chromium/chromoting/Chromoting.java
index 8fdd14d..15a8b15 100644
--- a/remoting/android/java/src/org/chromium/chromoting/Chromoting.java
+++ b/remoting/android/java/src/org/chromium/chromoting/Chromoting.java
@@ -90,8 +90,11 @@ public class Chromoting extends ActionBarActivity implements JniInterface.Connec
     /** Dialog for reporting connection progress. */
     private ProgressDialog mProgressIndicator;
 
-    /** Object for fetching OAuth2 access tokens from third party authorization servers. */
-    private ThirdPartyTokenFetcher mTokenFetcher;
+    /**
+     * Helper used by SessionConnection for session authentication. Receives onNewIntent()
+     * notifications to handle third-party authentication.
+     */
+    private SessionAuthenticator mAuthenticator;
 
     /**
      * This is set when receiving an authentication error from the HostListLoader. If that occurs,
@@ -214,10 +217,9 @@ public class Chromoting extends ActionBarActivity implements JniInterface.Connec
     @Override
     protected void onNewIntent(Intent intent) {
         super.onNewIntent(intent);
-        if (mTokenFetcher != null) {
-            if (mTokenFetcher.handleTokenFetched(intent)) {
-                mTokenFetcher = null;
-            }
+
+        if (mAuthenticator != null) {
+            mAuthenticator.onNewIntent(intent);
         }
     }
 
@@ -323,13 +325,11 @@ public class Chromoting extends ActionBarActivity implements JniInterface.Connec
                     @Override
                     public void onCancel(DialogInterface dialog) {
                         JniInterface.disconnectFromHost();
-                        mTokenFetcher = null;
                     }
                 });
         SessionConnector connector = new SessionConnector(this, this, mHostListLoader);
-        assert mTokenFetcher == null;
-        mTokenFetcher = createTokenFetcher(host);
-        connector.connectToHost(mAccount.name, mToken, host);
+        mAuthenticator = new SessionAuthenticator(this, host);
+        connector.connectToHost(mAccount.name, mToken, host, mAuthenticator);
     }
 
     private void refreshHostList() {
@@ -510,28 +510,4 @@ public class Chromoting extends ActionBarActivity implements JniInterface.Connec
             mProgressIndicator = null;
         }
     }
-
-    private ThirdPartyTokenFetcher createTokenFetcher(HostInfo host) {
-        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);
-            }
-        };
-        return new ThirdPartyTokenFetcher(this, host.getTokenUrlPatterns(), callback);
-    }
-
-    public void fetchThirdPartyToken(String tokenUrl, String clientId, String scope) {
-        assert mTokenFetcher != null;
-        mTokenFetcher.fetchToken(tokenUrl, clientId, scope);
-    }
 }
diff --git a/remoting/android/java/src/org/chromium/chromoting/SessionAuthenticator.java b/remoting/android/java/src/org/chromium/chromoting/SessionAuthenticator.java
new file mode 100644
index 0000000..a18c2f4
--- /dev/null
+++ b/remoting/android/java/src/org/chromium/chromoting/SessionAuthenticator.java
@@ -0,0 +1,168 @@
+// 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", "");
+    }
+}
diff --git a/remoting/android/java/src/org/chromium/chromoting/SessionConnector.java b/remoting/android/java/src/org/chromium/chromoting/SessionConnector.java
index 20fad25..cb57a21 100644
--- a/remoting/android/java/src/org/chromium/chromoting/SessionConnector.java
+++ b/remoting/android/java/src/org/chromium/chromoting/SessionConnector.java
@@ -15,6 +15,7 @@ public class SessionConnector implements JniInterface.ConnectionListener,
     private JniInterface.ConnectionListener mConnectionCallback;
     private HostListLoader.Callback mHostListCallback;
     private HostListLoader mHostListLoader;
+    private SessionAuthenticator mAuthenticator;
 
     private String mAccountName;
     private String mAuthToken;
@@ -43,11 +44,13 @@ public class SessionConnector implements JniInterface.ConnectionListener,
     }
 
     /** Initiates a connection to the host. */
-    public void connectToHost(String accountName, String authToken, HostInfo host) {
+    public void connectToHost(String accountName, String authToken, HostInfo host,
+            SessionAuthenticator authenticator) {
         mAccountName = accountName;
         mAuthToken = authToken;
         mHostId = host.id;
         mHostJabberId = host.jabberId;
+        mAuthenticator = authenticator;
 
         if (hostIncomplete(host)) {
             // These keys might not be present in a newly-registered host, so treat this as a
@@ -57,7 +60,7 @@ public class SessionConnector implements JniInterface.ConnectionListener,
         }
 
         JniInterface.connectToHost(accountName, authToken, host.jabberId, host.id, host.publicKey,
-                this);
+                this, mAuthenticator);
     }
 
     private static boolean hostIncomplete(HostInfo host) {
@@ -108,7 +111,7 @@ public class SessionConnector implements JniInterface.ConnectionListener,
             // Reconnect to the host, but use the original callback directly, instead of this
             // wrapper object, so the host list is not loaded again.
             JniInterface.connectToHost(mAccountName, mAuthToken, foundHost.jabberId,
-                    foundHost.id, foundHost.publicKey, mConnectionCallback);
+                    foundHost.id, foundHost.publicKey, mConnectionCallback, mAuthenticator);
         }
     }
 
diff --git a/remoting/android/java/src/org/chromium/chromoting/jni/JniInterface.java b/remoting/android/java/src/org/chromium/chromoting/jni/JniInterface.java
index a4f2fc5..7057179 100644
--- a/remoting/android/java/src/org/chromium/chromoting/jni/JniInterface.java
+++ b/remoting/android/java/src/org/chromium/chromoting/jni/JniInterface.java
@@ -4,27 +4,17 @@
 
 package org.chromium.chromoting.jni;
 
-import android.app.Activity;
-import android.app.AlertDialog;
 import android.content.Context;
-import android.content.DialogInterface;
-import android.content.SharedPreferences;
 import android.graphics.Bitmap;
 import android.graphics.Point;
-import android.os.Build;
 import android.os.Looper;
 import android.util.Log;
-import android.view.KeyEvent;
-import android.view.View;
-import android.widget.CheckBox;
-import android.widget.TextView;
-import android.widget.Toast;
 
 import org.chromium.base.CalledByNative;
 import org.chromium.base.JNINamespace;
 import org.chromium.chromoting.CapabilityManager;
-import org.chromium.chromoting.Chromoting;
 import org.chromium.chromoting.R;
+import org.chromium.chromoting.SessionAuthenticator;
 
 import java.nio.ByteBuffer;
 import java.nio.ByteOrder;
@@ -41,8 +31,8 @@ public class JniInterface {
     /** Whether the library has been loaded. Accessed on the UI thread. */
     private static boolean sLoaded = false;
 
-    /** The application context. Accessed on the UI thread. */
-    private static Activity sContext = null;
+    /** Used for authentication-related UX during connection. Accessed on the UI thread. */
+    private static SessionAuthenticator sAuthenticator;
 
     /** Interface used for connection state notifications. */
     public interface ConnectionListener {
@@ -152,9 +142,7 @@ public class JniInterface {
      * context, but not reload the library. This is useful e.g. when the activity is closed and the
      * user later wants to return to the application. Called on the UI thread.
      */
-    public static void loadLibrary(Activity context) {
-        sContext = context;
-
+    public static void loadLibrary(Context context) {
         if (sLoaded) return;
 
         System.loadLibrary("remoting_client_jni");
@@ -173,15 +161,21 @@ public class JniInterface {
     public static native String nativeGetClientId();
     public static native String nativeGetClientSecret();
 
+    /** Returns whether the client is connected. */
+    public static boolean isConnected() {
+        return sConnected;
+    }
+
     /** Attempts to form a connection to the user-selected host. Called on the UI thread. */
     public static void connectToHost(String username, String authToken,
-            String hostJid, String hostId, String hostPubkey, ConnectionListener listener) {
+            String hostJid, String hostId, String hostPubkey, ConnectionListener listener,
+            SessionAuthenticator authenticator) {
         disconnectFromHost();
 
         sConnectionListener = listener;
-        SharedPreferences prefs = sContext.getPreferences(Activity.MODE_PRIVATE);
+        sAuthenticator = authenticator;
         nativeConnect(username, authToken, hostJid, hostId, hostPubkey,
-                prefs.getString(hostId + "_id", ""), prefs.getString(hostId + "_secret", ""),
+                sAuthenticator.getPairingId(hostId), sAuthenticator.getPairingSecret(hostId),
                 sCapabilityManager.getLocalCapabilities());
         sConnected = true;
     }
@@ -238,69 +232,7 @@ public class JniInterface {
     /** Prompts the user to enter a PIN. Called on the UI thread. */
     @CalledByNative
     private static void displayAuthenticationPrompt(boolean pairingSupported) {
-        AlertDialog.Builder pinPrompt = new AlertDialog.Builder(sContext);
-        pinPrompt.setTitle(sContext.getString(R.string.title_authenticate));
-        pinPrompt.setMessage(sContext.getString(R.string.pin_message_android));
-        pinPrompt.setIcon(android.R.drawable.ic_lock_lock);
-
-        final View pinEntry = sContext.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) {
-                        Log.i("jniiface", "User provided a PIN code");
-                        if (sConnected) {
-                            nativeAuthenticationResponse(String.valueOf(pinTextView.getText()),
-                                    pinCheckBox.isChecked(), Build.MODEL);
-                        } else {
-                            String message = sContext.getString(R.string.error_network_error);
-                            Toast.makeText(sContext, message, Toast.LENGTH_LONG).show();
-                        }
-                    }
-                });
-
-        pinPrompt.setNegativeButton(
-                R.string.cancel, new DialogInterface.OnClickListener() {
-                    @Override
-                    public void onClick(DialogInterface dialog, int which) {
-                        Log.i("jniiface", "User canceled pin entry prompt");
-                        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();
+        sAuthenticator.displayAuthenticationPrompt(pairingSupported);
     }
 
     /**
@@ -310,24 +242,20 @@ public class JniInterface {
      * @param deviceName The device name to appear in the pairing registry. Only used if createPair
      *                   is true.
      */
+    public static void handleAuthenticationResponse(String pin, boolean createPair,
+            String deviceName) {
+        assert sConnected;
+        nativeAuthenticationResponse(pin, createPair, deviceName);
+    }
+
+    /** Native implementation of handleAuthenticationResponse(). */
     private static native void nativeAuthenticationResponse(String pin, boolean createPair,
             String deviceName);
 
     /** Saves newly-received pairing credentials to permanent storage. Called on the UI thread. */
     @CalledByNative
     private static void commitPairingCredentials(String host, String id, String secret) {
-        // Empty |id| indicates that pairing needs to be removed.
-        if (id.isEmpty()) {
-            sContext.getPreferences(Activity.MODE_PRIVATE).edit()
-                    .remove(host + "_id")
-                    .remove(host + "_secret")
-                    .apply();
-        } else {
-            sContext.getPreferences(Activity.MODE_PRIVATE).edit()
-                    .putString(host + "_id", id)
-                    .putString(host + "_secret", secret)
-                    .apply();
-        }
+        sAuthenticator.commitPairingCredentials(host, id, secret);
     }
 
     /**
@@ -498,8 +426,7 @@ public class JniInterface {
     /** Pops up a third party login page to fetch the token required for authentication. */
     @CalledByNative
     public static void fetchThirdPartyToken(String tokenUrl, String clientId, String scope) {
-        Chromoting app = (Chromoting) sContext;
-        app.fetchThirdPartyToken(tokenUrl, clientId, scope);
+        sAuthenticator.fetchThirdPartyToken(tokenUrl, clientId, scope);
     }
 
     /**