add IsSingleton to OT's application API (#398)

include/openthread.h

@@ -226,6 +226,15 @@ ThreadError otThreadStart(void);
  */
 ThreadError otThreadStop(void);
 
+/**
+ * This function indicates whether a node is the only router on the network.
+ *
+ * @retval TRUE   It is the only router in the network.
+ * @retval FALSE  It is a child or is not a single router in the network.
+ *
+ */
+bool otIsSingleton(void);
+
 /**
  * This function pointer is called during an IEEE 802.15.4 Active Scan when an IEEE 802.15.4 Beacon is received or
  * the scan completes.

src/cli/cli.cpp

@@ -88,6 +88,7 @@ const struct Command Interpreter::sCommands[] =
     { "router", &ProcessRouter },
     { "routerupgradethreshold", &ProcessRouterUpgradeThreshold },
     { "scan", &ProcessScan },
+    { "singleton", &ProcessSingleton },
     { "state", &ProcessState },
     { "thread", &ProcessThread },
     { "version", &ProcessVersion },
@@ -1542,6 +1543,25 @@ exit:
     return;
 }
 
+void Interpreter::ProcessSingleton(int argc, char *argv[])
+{
+    ThreadError error = kThreadError_None;
+
+    if (otIsSingleton())
+    {
+        sServer->OutputFormat("true\r\n");
+    }
+    else
+    {
+        sServer->OutputFormat("false\r\n");
+    }
+
+    (void)argc;
+    (void)argv;
+
+    AppendResult(error);
+}
+
 void Interpreter::ProcessState(int argc, char *argv[])
 {
     ThreadError error = kThreadError_None;

src/cli/cli.hpp

@@ -172,6 +172,7 @@ private:
     static void ProcessRouterUpgradeThreshold(int argc, char *argv[]);
     static void ProcessRloc16(int argc, char *argv[]);
     static void ProcessScan(int argc, char *argv[]);
+    static void ProcessSingleton(int argc, char *argv[]);
     static void ProcessState(int argc, char *argv[]);
     static void ProcessThread(int argc, char *argv[]);
     static void ProcessVersion(int argc, char *argv[]);

src/core/openthread.cpp

@@ -903,6 +903,11 @@ exit:
     return error;
 }
 
+bool otIsSingleton(void)
+{
+    return mEnabled && sThreadNetif->GetMle().IsSingleton();
+}
+
 ThreadError otActiveScan(uint32_t aScanChannels, uint16_t aScanDuration, otHandleActiveScanResult aCallback)
 {
     return sThreadNetif->GetMac().ActiveScan(aScanChannels, aScanDuration, &HandleActiveScanResult,

src/core/thread/mle_router.hpp

@@ -97,6 +97,15 @@ public:
      */
     void SetRouterRoleEnabled(bool aEnabled);
 
+    /**
+     * This method indicates whether a node is the only router on the network.
+     *
+     * @retval TRUE   It is the only router in the network.
+     * @retval FALSE  It is a child or is not a single router in the network.
+     *
+     */
+    bool IsSingleton(void);
+
     /**
      * This method generates an Address Solicit request for a Router ID.
      *
@@ -440,7 +449,6 @@ private:
     ThreadError HandleChildUpdateRequest(const Message &aMessage, const Ip6::MessageInfo &aMessageInfo);
     ThreadError HandleDataRequest(const Message &aMessage, const Ip6::MessageInfo &aMessageInfo);
     ThreadError HandleNetworkDataUpdateRouter(void);
-    bool IsSingleton(void);
 
     ThreadError ProcessRouteTlv(const RouteTlv &aRoute);
     ThreadError ResetAdvertiseInterval(void);