Check if VoIP API is supported in SipManager.

This is to make SipManager.isVoipSupported() effective.
Also add NPE check now that we may return null SipAudioCall when VOIP is not
supported.

Bug: 3251016

Change-Id: Icd551123499f55eef190743b90980922893c4a13

Author: Hung-ying Tyan

voip/java/android/net/sip/SipAudioCall.java

@@ -519,10 +519,15 @@ private void onError(int errorCode, String message) {
      * @param session the session that receives the incoming call
      * @param sessionDescription the session description of the incoming call
      * @throws SipException if the SIP service fails to attach this object to
-     *        the session
+     *        the session or VOIP API is not supported by the device
+     * @see SipManager#isVoipSupported
      */
     public void attachCall(SipSession session, String sessionDescription)
             throws SipException {
+        if (!SipManager.isVoipSupported(mContext)) {
+            throw new SipException("VOIP API is not supported");
+        }
+
         synchronized (this) {
             mSipSession = session;
             mPeerSd = sessionDescription;
@@ -548,10 +553,15 @@ public void attachCall(SipSession session, String sessionDescription)
      *        SIP protocol) is used if {@code timeout} is zero or negative.
      * @see Listener#onError
      * @throws SipException if the SIP service fails to create a session for the
-     *        call
+     *        call or VOIP API is not supported by the device
+     * @see SipManager#isVoipSupported
      */
     public void makeCall(SipProfile peerProfile, SipSession sipSession,
             int timeout) throws SipException {
+        if (!SipManager.isVoipSupported(mContext)) {
+            throw new SipException("VOIP API is not supported");
+        }
+
         synchronized (this) {
             mSipSession = sipSession;
             try {
@@ -595,6 +605,9 @@ public void endCall() throws SipException {
     public void holdCall(int timeout) throws SipException {
         synchronized (this) {
             if (mHold) return;
+            if (mSipSession == null) {
+                throw new SipException("Not in a call to hold call");
+            }
             mSipSession.changeCall(createHoldOffer().encode(), timeout);
             mHold = true;
             setAudioGroupMode();
@@ -614,6 +627,9 @@ public void holdCall(int timeout) throws SipException {
      */
     public void answerCall(int timeout) throws SipException {
         synchronized (this) {
+            if (mSipSession == null) {
+                throw new SipException("No call to answer");
+            }
             try {
                 mAudioStream = new AudioStream(InetAddress.getByName(
                         getLocalIp()));

voip/java/android/net/sip/SipManager.java

@@ -133,7 +133,7 @@ public static boolean isApiSupported(Context context) {
     }
 
     /**
-     * Returns true if the system supports SIP-based VoIP.
+     * Returns true if the system supports SIP-based VOIP API.
      */
     public static boolean isVoipSupported(Context context) {
         return context.getPackageManager().hasSystemFeature(
@@ -305,12 +305,17 @@ public boolean isRegistered(String localProfileUri) throws SipException {
      * @param timeout the timeout value in seconds. Default value (defined by
      *        SIP protocol) is used if {@code timeout} is zero or negative.
      * @return a {@link SipAudioCall} object
-     * @throws SipException if calling the SIP service results in an error
+     * @throws SipException if calling the SIP service results in an error or
+     *      VOIP API is not supported by the device
      * @see SipAudioCall.Listener#onError
+     * @see #isVoipSupported
      */
     public SipAudioCall makeAudioCall(SipProfile localProfile,
             SipProfile peerProfile, SipAudioCall.Listener listener, int timeout)
             throws SipException {
+        if (!isVoipSupported(mContext)) {
+            throw new SipException("VOIP API is not supported");
+        }
         SipAudioCall call = new SipAudioCall(mContext, localProfile);
         call.setListener(listener);
         SipSession s = createSipSession(localProfile, null);
@@ -332,12 +337,17 @@ public SipAudioCall makeAudioCall(SipProfile localProfile,
      * @param timeout the timeout value in seconds. Default value (defined by
      *        SIP protocol) is used if {@code timeout} is zero or negative.
      * @return a {@link SipAudioCall} object
-     * @throws SipException if calling the SIP service results in an error
+     * @throws SipException if calling the SIP service results in an error or
+     *      VOIP API is not supported by the device
      * @see SipAudioCall.Listener#onError
+     * @see #isVoipSupported
      */
     public SipAudioCall makeAudioCall(String localProfileUri,
             String peerProfileUri, SipAudioCall.Listener listener, int timeout)
             throws SipException {
+        if (!isVoipSupported(mContext)) {
+            throw new SipException("VOIP API is not supported");
+        }
         try {
             return makeAudioCall(
                     new SipProfile.Builder(localProfileUri).build(),