EncryptMessage triggers an exception when it fails

java/android/OlmLibSdk/olm-sdk/src/androidTest/java/org/matrix/olm/OlmGroupSessionTest.java

@@ -113,7 +113,11 @@ public class OlmGroupSessionTest {
     @Test
     public void test05OutboundGroupEncryptMessage() {
         // alice encrypts a message to bob
-        mAliceToBobMessage = mAliceOutboundGroupSession.encryptMessage(CLEAR_MESSAGE1);
+        try {
+            mAliceToBobMessage = mAliceOutboundGroupSession.encryptMessage(CLEAR_MESSAGE1);
+        } catch (OlmOutboundGroupSession.EncryptMessageException e) {
+            assertTrue("Exception in bob encryptMessage, Exception code=" + e.getMessage(), false);
+        }
         assertFalse(TextUtils.isEmpty(mAliceToBobMessage));
 
         // test message index after encryption is incremented

java/android/OlmLibSdk/olm-sdk/src/main/java/org/matrix/olm/OlmOutboundGroupSession.java

@@ -42,6 +42,15 @@ public class OlmOutboundGroupSession extends CommonSerializeUtils implements Ser
      */
     private transient long mNativeId;
 
+    /**
+     * Exception triggered in {@link #encryptMessage(String)}
+     */
+    static public class EncryptMessageException extends Exception {
+        public EncryptMessageException(String message) {
+            super(message);
+        }
+    }
+
     /**
      * Constructor.<br>
      * Create and save a new session native instance ID and
@@ -252,22 +261,34 @@ public class OlmOutboundGroupSession extends CommonSerializeUtils implements Ser
      * Encrypt some plain-text message.<br>
      * The message given as parameter is encrypted and returned as the return value.
      * @param aClearMsg message to be encrypted
-     * @return the encrypted message if operation succeed, null otherwise
+     * @return the encrypted message
+     * @exception EncryptMessageException the encryption failure reason
      */
-    public String encryptMessage(String aClearMsg) {
+    public String encryptMessage(String aClearMsg) throws EncryptMessageException {
         String retValue = null;
 
-        if(!TextUtils.isEmpty(aClearMsg)) {
+        if (!TextUtils.isEmpty(aClearMsg)) {
+            StringBuffer errorMsg = new StringBuffer();
+
             try {
-                retValue = new String(encryptMessageJni(aClearMsg.getBytes("UTF-8")), "UTF-8");
+                byte[] encryptedBuffer = encryptMessageJni(aClearMsg.getBytes("UTF-8"), errorMsg);
+
+                if (null != encryptedBuffer) {
+                    retValue = new String(encryptedBuffer , "UTF-8");
+                }
             } catch (Exception e) {
                 Log.e(LOG_TAG, "## encryptMessage() failed " + e.getMessage());
+                errorMsg.append(e.getMessage());
+            }
+
+            if (0 != errorMsg.length()) {
+                throw new EncryptMessageException(errorMsg.toString());
             }
         }
 
         return retValue;
     }
-    private native byte[] encryptMessageJni(byte[] aClearMsgBuffer);
+    private native byte[] encryptMessageJni(byte[] aClearMsgBuffer, StringBuffer aErrorMsg);
 
     /**
      * Return true the object resources have been released.<br>

java/android/OlmLibSdk/olm-sdk/src/main/jni/olm_outbound_group_session.cpp

@@ -268,7 +268,7 @@ JNIEXPORT jbyteArray OLM_OUTBOUND_GROUP_SESSION_FUNC_DEF(sessionKeyJni)(JNIEnv *
     return returnValue;
 }
 
-JNIEXPORT jbyteArray OLM_OUTBOUND_GROUP_SESSION_FUNC_DEF(encryptMessageJni)(JNIEnv *env, jobject thiz, jbyteArray aClearMsgBuffer)
+JNIEXPORT jbyteArray OLM_OUTBOUND_GROUP_SESSION_FUNC_DEF(encryptMessageJni)(JNIEnv *env, jobject thiz, jbyteArray aClearMsgBuffer, jobject aErrorMsg)
 {
     LOGD("## encryptMessageJni(): IN");
 
@@ -277,10 +277,17 @@ JNIEXPORT jbyteArray OLM_OUTBOUND_GROUP_SESSION_FUNC_DEF(encryptMessageJni)(JNIE
     OlmOutboundGroupSession *sessionPtr = NULL;
     jbyte* clearMsgPtr = NULL;
 
+    jclass errorMsgJClass = 0;
+    jmethodID errorMsgMethodId = 0;
+
     if (!(sessionPtr = (OlmOutboundGroupSession*)getOutboundGroupSessionInstanceId(env,thiz)))
     {
         LOGE(" ## encryptMessageJni(): failure - invalid outbound group session ptr=NULL");
     }
+    else if (!aErrorMsg)
+    {
+        LOGE(" ## encryptMessageJni(): failure - invalid error output");
+    }
     else if (!aClearMsgBuffer)
     {
         LOGE(" ## encryptMessageJni(): failure - invalid clear message");
@@ -289,6 +296,14 @@ JNIEXPORT jbyteArray OLM_OUTBOUND_GROUP_SESSION_FUNC_DEF(encryptMessageJni)(JNIE
     {
         LOGE(" ## encryptMessageJni(): failure - clear message JNI allocation OOM");
     }
+    else if (!(errorMsgJClass = env->GetObjectClass(aErrorMsg)))
+    {
+        LOGE(" ## encryptMessageJni(): failure - unable to get error class");
+    }
+    else if (!(errorMsgMethodId = env->GetMethodID(errorMsgJClass, "append", "(Ljava/lang/String;)Ljava/lang/StringBuffer;")))
+    {
+        LOGE(" ## encryptMessageJni(): failure - unable to get error method ID");
+    }
     else
     {
         // get clear message length
@@ -312,9 +327,19 @@ JNIEXPORT jbyteArray OLM_OUTBOUND_GROUP_SESSION_FUNC_DEF(encryptMessageJni)(JNIE
                                                        clearMsgLength,
                                                        encryptedMsgPtr,
                                                        encryptedMsgLength);
+
+
             if (encryptedLength == olm_error())
             {
-                LOGE(" ## encryptMessageJni(): failure - olm_group_encrypt Msg=%s",(const char *)olm_outbound_group_session_last_error(sessionPtr));
+                const char * errorMsgPtr = olm_outbound_group_session_last_error(sessionPtr);
+                LOGE(" ## encryptMessageJni(): failure - olm_group_decrypt_max_plaintext_length Msg=%s",errorMsgPtr);
+
+                jstring errorJstring = env->NewStringUTF(errorMsgPtr);
+
+                if (errorJstring)
+                {
+                    env->CallObjectMethod(aErrorMsg, errorMsgMethodId, errorJstring);
+                }
             }
             else
             {
@@ -329,7 +354,7 @@ JNIEXPORT jbyteArray OLM_OUTBOUND_GROUP_SESSION_FUNC_DEF(encryptMessageJni)(JNIE
 
             free(encryptedMsgPtr);
          }
-      }
+    }
 
     // free alloc
     if (clearMsgPtr)

java/android/OlmLibSdk/olm-sdk/src/main/jni/olm_outbound_group_session.h

@@ -37,7 +37,7 @@ JNIEXPORT jbyteArray OLM_OUTBOUND_GROUP_SESSION_FUNC_DEF(sessionIdentifierJni)(J
 JNIEXPORT jint OLM_OUTBOUND_GROUP_SESSION_FUNC_DEF(messageIndexJni)(JNIEnv *env, jobject thiz);
 JNIEXPORT jbyteArray OLM_OUTBOUND_GROUP_SESSION_FUNC_DEF(sessionKeyJni)(JNIEnv *env, jobject thiz);
 
-JNIEXPORT jbyteArray OLM_OUTBOUND_GROUP_SESSION_FUNC_DEF(encryptMessageJni)(JNIEnv *env, jobject thiz, jbyteArray aClearMsgBuffer);
+JNIEXPORT jbyteArray OLM_OUTBOUND_GROUP_SESSION_FUNC_DEF(encryptMessageJni)(JNIEnv *env, jobject thiz, jbyteArray aClearMsgBuffer, jobject aErrorMsg);
 
 // serialization
 JNIEXPORT jstring OLM_OUTBOUND_GROUP_SESSION_FUNC_DEF(serializeDataWithKeyJni)(JNIEnv *env, jobject thiz, jbyteArray aKey, jobject aErrorMsg);