Support for Telecom Call IDs.

Add support for caching telecom call ID in connection and conference
classes.

Enhance connection service call ID generation:
For "existing calls", the connection service will try to use a call ID
of the format ClassName@ID
Where ClassName is the ComponentName of the connection service, and ID
is a unique incrementing ID for the connection service.

Bug: 23357902
Change-Id: I2284b018465e2b330fc8a3b556758e9f34a2daba
diff --git a/telecomm/java/android/telecom/ConnectionService.java b/telecomm/java/android/telecom/ConnectionService.java
index 383e45b..f6ba53b 100644
--- a/telecomm/java/android/telecom/ConnectionService.java
+++ b/telecomm/java/android/telecom/ConnectionService.java
@@ -115,6 +115,8 @@
 
     private boolean mAreAccountsInitialized = false;
     private Conference sNullConference;
+    private Object mIdSyncRoot = new Object();
+    private int mId = 0;
 
     private final IBinder mBinder = new IConnectionService.Stub() {
         @Override
@@ -611,7 +613,8 @@
             boolean isIncoming,
             boolean isUnknown) {
         Log.d(this, "createConnection, callManagerAccount: %s, callId: %s, request: %s, " +
-                "isIncoming: %b, isUnknown: %b", callManagerAccount, callId, request, isIncoming,
+                        "isIncoming: %b, isUnknown: %b", callManagerAccount, callId, request,
+                isIncoming,
                 isUnknown);
 
         Connection connection = isUnknown ? onCreateUnknownConnection(callManagerAccount, request)
@@ -623,6 +626,7 @@
                     new DisconnectCause(DisconnectCause.ERROR));
         }
 
+        connection.setTelecomCallId(callId);
         if (connection.getState() != Connection.STATE_DISCONNECTED) {
             addConnection(callId, connection);
         }
@@ -930,6 +934,7 @@
                     connectionIds.add(mIdByConnection.get(connection));
                 }
             }
+            conference.setTelecomCallId(id);
             ParcelableConference parcelableConference = new ParcelableConference(
                     conference.getPhoneAccountHandle(),
                     conference.getState(),
@@ -966,7 +971,7 @@
     public final void addExistingConnection(PhoneAccountHandle phoneAccountHandle,
             Connection connection) {
 
-        String id = addExistingConnectionInternal(connection);
+        String id = addExistingConnectionInternal(phoneAccountHandle, connection);
         if (id != null) {
             List<String> emptyList = new ArrayList<>(0);
 
@@ -1128,18 +1133,29 @@
     }
 
     /**
-     * Adds an existing connection to the list of connections, identified by a new UUID.
+     * Adds an existing connection to the list of connections, identified by a new call ID unique
+     * to this connection service.
      *
      * @param connection The connection.
-     * @return The UUID of the connection (e.g. the call-id).
+     * @return The ID of the connection (e.g. the call-id).
      */
-    private String addExistingConnectionInternal(Connection connection) {
-        String id = UUID.randomUUID().toString();
+    private String addExistingConnectionInternal(PhoneAccountHandle handle, Connection connection) {
+        String id;
+        if (handle == null) {
+            // If no phone account handle was provided, we cannot be sure the call ID is unique,
+            // so just use a random UUID.
+            id = UUID.randomUUID().toString();
+        } else {
+            // Phone account handle was provided, so use the ConnectionService class name as a
+            // prefix for a unique incremental call ID.
+            id = handle.getComponentName().getClassName() + "@" + getNextCallId();
+        }
         addConnection(id, connection);
         return id;
     }
 
     private void addConnection(String callId, Connection connection) {
+        connection.setTelecomCallId(callId);
         mConnectionById.put(callId, connection);
         mIdByConnection.put(connection, callId);
         connection.addConnectionListener(mConnectionListener);
@@ -1160,6 +1176,9 @@
         if (mIdByConference.containsKey(conference)) {
             Log.w(this, "Re-adding an existing conference: %s.", conference);
         } else if (conference != null) {
+            // Conferences do not (yet) have a PhoneAccountHandle associated with them, so we
+            // cannot determine a ConnectionService class name to associate with the ID, so use
+            // a unique UUID (for now).
             String id = UUID.randomUUID().toString();
             mConferenceById.put(id, conference);
             mIdByConference.put(conference, id);
@@ -1261,4 +1280,15 @@
             conference.onDisconnect();
         }
     }
+
+    /**
+     * Retrieves the next call ID as maintainted by the connection service.
+     *
+     * @return The call ID.
+     */
+    private int getNextCallId() {
+        synchronized(mIdSyncRoot) {
+            return ++mId;
+        }
+    }
 }