Add Bluetooth Rpcs needed to support making the device discoverable. (#41)

* Add Bluetooth Rpcs needed to support making the device discoverable.
* Fix a bug in serializer; fix a typo in an Rpc name.

Related to #8 

2 files changed, 97 insertions, 5 deletions

diff --git a/src/main/java/com/google/android/mobly/snippet/bundled/BluetoothAdapterSnippet.java b/src/main/java/com/google/android/mobly/snippet/bundled/BluetoothAdapterSnippet.java
index a6e6dbb..7a0a15e 100644
--- a/src/main/java/com/google/android/mobly/snippet/bundled/BluetoothAdapterSnippet.java
+++ b/src/main/java/com/google/android/mobly/snippet/bundled/BluetoothAdapterSnippet.java
@@ -75,6 +75,11 @@ public class BluetoothAdapterSnippet implements Snippet {
         }
     }
 
+    @Rpc(description = "Return true if Bluetooth is enabled, false otherwise.")
+    public boolean btIsEnabled() {
+        return mBluetoothAdapter.isEnabled();
+    }
+
     @Rpc(
         description =
                 "Get bluetooth discovery results, which is a list of serialized BluetoothDevice objects."
@@ -87,12 +92,29 @@ public class BluetoothAdapterSnippet implements Snippet {
         return results;
     }
 
+    @Rpc(description = "Set the friendly Bluetooth name of the local Bluetooth adapter.")
+    public void btSetName(String name) throws BluetoothAdapterSnippetException {
+        if (!btIsEnabled()) {
+            throw new BluetoothAdapterSnippetException(
+                    "Bluetooth is not enabled, cannot set Bluetooth name.");
+        }
+        if (!mBluetoothAdapter.setName(name)) {
+            throw new BluetoothAdapterSnippetException(
+                    "Failed to set local Bluetooth name to " + name);
+        }
+    }
+
+    @Rpc(description = "Get the friendly Bluetooth name of the local Bluetooth adapter.")
+    public String btGetName() {
+        return mBluetoothAdapter.getName();
+    }
+
     @Rpc(
         description =
                 "Start discovery, wait for discovery to complete, and return results, which is a list of "
                         + "serialized BluetoothDevice objects."
     )
-    public JSONArray btDiscoveryAndGetResults()
+    public JSONArray btDiscoverAndGetResults()
             throws InterruptedException, JSONException, BluetoothAdapterSnippetException {
         IntentFilter filter = new IntentFilter(BluetoothDevice.ACTION_FOUND);
         filter.addAction(BluetoothAdapter.ACTION_DISCOVERY_FINISHED);
@@ -118,6 +140,52 @@ public class BluetoothAdapterSnippet implements Snippet {
         return btGetCachedScanResults();
     }
 
+    @Rpc(description = "Become discoverable in Bluetooth.")
+    public void btBecomeDiscoverable(Integer duration) throws Throwable {
+        if (!btIsEnabled()) {
+            throw new BluetoothAdapterSnippetException(
+                    "Bluetooth is not enabled, cannot become discoverable.");
+        }
+        boolean success;
+        try {
+            success =
+                    (boolean)
+                            mBluetoothAdapter
+                                    .getClass()
+                                    .getDeclaredMethod("setScanMode", int.class, int.class)
+                                    .invoke(
+                                            mBluetoothAdapter,
+                                            BluetoothAdapter.SCAN_MODE_CONNECTABLE_DISCOVERABLE,
+                                            duration);
+        } catch (InvocationTargetException e) {
+            throw e.getCause();
+        }
+        if (!success) {
+            throw new BluetoothAdapterSnippetException("Failed to become discoverable.");
+        }
+    }
+
+    @Rpc(description = "Stop being discoverable in Bluetooth.")
+    public void btStopBeingDiscoverable() throws Throwable {
+        boolean success;
+        try {
+            success =
+                    (boolean)
+                            mBluetoothAdapter
+                                    .getClass()
+                                    .getDeclaredMethod("setScanMode", int.class, int.class)
+                                    .invoke(
+                                            mBluetoothAdapter,
+                                            BluetoothAdapter.SCAN_MODE_NONE,
+                                            0 /* duration is not used for this */);
+        } catch (InvocationTargetException e) {
+            throw e.getCause();
+        }
+        if (!success) {
+            throw new BluetoothAdapterSnippetException("Failed to stop being discoverable.");
+        }
+    }
+
     @Rpc(description = "Get the list of paired bluetooth devices.")
     public JSONArray btGetPairedDevices()
             throws BluetoothAdapterSnippetException, InterruptedException, JSONException {
diff --git a/src/main/java/com/google/android/mobly/snippet/bundled/utils/JsonSerializer.java b/src/main/java/com/google/android/mobly/snippet/bundled/utils/JsonSerializer.java
index fc7d17b..bd00f45 100644
--- a/src/main/java/com/google/android/mobly/snippet/bundled/utils/JsonSerializer.java
+++ b/src/main/java/com/google/android/mobly/snippet/bundled/utils/JsonSerializer.java
@@ -109,13 +109,13 @@ public class JsonSerializer {
     private JSONObject serializeWifiConfiguration(WifiConfiguration data) throws JSONException {
         JSONObject result = new JSONObject(mGson.toJson(data));
         result.put("Status", WifiConfiguration.Status.strings[data.status]);
-        result.put("SSID", trimQuotationMarks(data.SSID));
+        guaranteedPut(result, "SSID", trimQuotationMarks(data.SSID));
         return result;
     }
 
     private JSONObject serializeWifiInfo(WifiInfo data) throws JSONException {
         JSONObject result = new JSONObject(mGson.toJson(data));
-        result.put("SSID", trimQuotationMarks(data.getSSID()));
+        guaranteedPut(result, "SSID", trimQuotationMarks(data.getSSID()));
         for (SupplicantState state : SupplicantState.values()) {
             if (data.getSupplicantState().equals(state)) {
                 result.put("SupplicantState", state.name());
@@ -126,7 +126,7 @@ public class JsonSerializer {
 
     private JSONObject serializeBluetoothDevice(BluetoothDevice data) throws JSONException {
         JSONObject result = new JSONObject();
-        result.put("Address", data.getAddress());
+        guaranteedPut(result, "Address", data.getAddress());
         final String bondStateFieldName = "BondState";
         switch (data.getBondState()) {
             case BluetoothDevice.BOND_NONE:
@@ -139,7 +139,7 @@ public class JsonSerializer {
                 result.put(bondStateFieldName, "BOND_BONDED");
                 break;
         }
-        result.put("Name", data.getName());
+        guaranteedPut(result, "Name", data.getName());
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR2) {
             final String deviceTypeFieldName = "DeviceType";
             switch (data.getType()) {
@@ -167,4 +167,28 @@ public class JsonSerializer {
         }
         return result;
     }
+
+    /**
+     * Guarantees a field is put into a JSONObject even if it's null.
+     *
+     * <p>By default, if the object of {@link JSONObject#put(String, Object)} is null, the `put`
+     * method would either remove the field or do nothing, causing serialized objects to have
+     * inconsistent fields.
+     *
+     * <p>Use this method to put objects that may be null into the serialized JSONObject so the
+     * serialized objects have a consistent set of critical fields, like the SSID field in
+     * serialized WifiConfiguration objects.
+     *
+     * @param data
+     * @param name
+     * @param object
+     * @throws JSONException
+     */
+    private void guaranteedPut(JSONObject data, String name, Object object) throws JSONException {
+        if (object == null) {
+            data.put(name, JSONObject.NULL);
+        } else {
+            data.put(name, object);
+        }
+    }
 }