Update decryptMessage() API with the error message as an output parameter

3 files changed, 46 insertions, 9 deletions

diff --git a/java/android/OlmLibSdk/olm-sdk/src/main/java/org/matrix/olm/OlmInboundGroupSession.java b/java/android/OlmLibSdk/olm-sdk/src/main/java/org/matrix/olm/OlmInboundGroupSession.java
index 664b22e..073058a 100644
--- a/java/android/OlmLibSdk/olm-sdk/src/main/java/org/matrix/olm/OlmInboundGroupSession.java
+++ b/java/android/OlmLibSdk/olm-sdk/src/main/java/org/matrix/olm/OlmInboundGroupSession.java
@@ -45,7 +45,7 @@ public class OlmInboundGroupSession extends CommonSerializeUtils implements Seri
     private transient long mNativeId;
 
     /**
-     * Wrapper class to be used in {@link #decryptMessage(String, DecryptIndex)}
+     * Wrapper class to be used in {@link #decryptMessage(String, DecryptIndex, StringBuffer)}
      */
     static public class DecryptIndex {
         /** decrypt index **/
@@ -142,16 +142,26 @@ public class OlmInboundGroupSession extends CommonSerializeUtils implements Seri
 
 
     /**
-     * Decrypt the message passed in parameter.
+     * Decrypt the message passed in parameter.<br>
+     * In case of error, null is returned and an error message description is provided in aErrorMsg.
      * @param aEncryptedMsg the message to be decrypted
      * @param aDecryptIndex_out decrypted message index
+     * @param aErrorMsg error message description
      * @return the decrypted message if operation succeed, null otherwise.
      */
-    public String decryptMessage(String aEncryptedMsg, DecryptIndex aDecryptIndex_out) {
-        String decryptedMessage = decryptMessageJni(aEncryptedMsg, aDecryptIndex_out, OlmManager.ENABLE_STRING_UTF8_SPECIFIC_CONVERSION);
+    public String decryptMessage(String aEncryptedMsg, DecryptIndex aDecryptIndex_out, StringBuffer aErrorMsg) {
+        String decryptedMessage = null;
+
+        // sanity check
+        if(null == aErrorMsg) {
+            Log.e(LOG_TAG,"## decryptMessage(): invalid parameter - aErrorMsg=null");
+        } else {
+            aErrorMsg.setLength(0);
+            decryptedMessage = decryptMessageJni(aEncryptedMsg, aDecryptIndex_out, aErrorMsg, OlmManager.ENABLE_STRING_UTF8_SPECIFIC_CONVERSION);
+        }
         return decryptedMessage;
     }
-    private native String decryptMessageJni(String aEncryptedMsg, DecryptIndex aDecryptIndex_out, boolean aIsUtf8ConversionRequired);
+    private native String decryptMessageJni(String aEncryptedMsg, DecryptIndex aDecryptIndex_out, StringBuffer aErrorMsg, boolean aIsUtf8ConversionRequired);
 
 
     /**
diff --git a/java/android/OlmLibSdk/olm-sdk/src/main/jni/olm_inbound_group_session.cpp b/java/android/OlmLibSdk/olm-sdk/src/main/jni/olm_inbound_group_session.cpp
index e450a4c..6d11b38 100644
--- a/java/android/OlmLibSdk/olm-sdk/src/main/jni/olm_inbound_group_session.cpp
+++ b/java/android/OlmLibSdk/olm-sdk/src/main/jni/olm_inbound_group_session.cpp
@@ -180,7 +180,7 @@ JNIEXPORT jstring OLM_INBOUND_GROUP_SESSION_FUNC_DEF(sessionIdentifierJni)(JNIEn
 }
 
 
-JNIEXPORT jstring OLM_INBOUND_GROUP_SESSION_FUNC_DEF(decryptMessageJni)(JNIEnv *env, jobject thiz, jstring aEncryptedMsg, jobject aDecryptIndex, jboolean aIsUtf8ConversionRequired)
+JNIEXPORT jstring OLM_INBOUND_GROUP_SESSION_FUNC_DEF(decryptMessageJni)(JNIEnv *env, jobject thiz, jstring aEncryptedMsg, jobject aDecryptIndex, jobject aErrorMsg, jboolean aIsUtf8ConversionRequired)
 {
     jstring decryptedMsgRetValue = 0;
     OlmInboundGroupSession *sessionPtr = NULL;
@@ -190,6 +190,10 @@ JNIEXPORT jstring OLM_INBOUND_GROUP_SESSION_FUNC_DEF(decryptMessageJni)(JNIEnv *
     uint32_t messageIndex = 0;
     jclass indexObjJClass = 0;
     jfieldID indexMsgFieldId;
+    jclass errorMsgJClass = 0;
+    jmethodID errorMsgMethodId = 0;
+    jstring errorJstring = 0;
+    const char *errorMsgPtr = NULL;
 
     LOGD("## decryptMessageJni(): inbound group session IN");
 
@@ -205,6 +209,18 @@ JNIEXPORT jstring OLM_INBOUND_GROUP_SESSION_FUNC_DEF(decryptMessageJni)(JNIEnv *
     {
         LOGE(" ## decryptMessageJni(): failure - invalid index object");
     }
+    else if(0 == aErrorMsg)
+    {
+        LOGE(" ## decryptMessageJni(): failure - invalid error object");
+    }
+    else if(0 == (errorMsgJClass = env->GetObjectClass(aErrorMsg)))
+    {
+        LOGE(" ## decryptMessageJni(): failure - unable to get error class");
+    }
+    else if(0 == (errorMsgMethodId = env->GetMethodID(errorMsgJClass, "append", "(Ljava/lang/String;)Ljava/lang/StringBuffer;")))
+    {
+        LOGE(" ## decryptMessageJni(): failure - unable to get error method ID");
+    }
     else if(0 == (encryptedMsgPtr = env->GetStringUTFChars(aEncryptedMsg, 0)))
     {
         LOGE(" ## decryptMessageJni(): failure - encrypted message JNI allocation OOM");
@@ -238,7 +254,12 @@ JNIEXPORT jstring OLM_INBOUND_GROUP_SESSION_FUNC_DEF(decryptMessageJni)(JNIEnv *
                                                                                encryptedMsgLength);
             if(maxPlainTextLength == olm_error())
             {
-                LOGE(" ## decryptMessageJni(): failure - olm_group_decrypt_max_plaintext_length Msg=%s",(const char *)olm_inbound_group_session_last_error(sessionPtr));
+                errorMsgPtr = olm_inbound_group_session_last_error(sessionPtr);
+                LOGE(" ## decryptMessageJni(): failure - olm_group_decrypt_max_plaintext_length Msg=%s",errorMsgPtr);
+                if(0 != (errorJstring = env->NewStringUTF(errorMsgPtr)))
+                {
+                    env->CallObjectMethod(aErrorMsg, errorMsgMethodId, errorJstring);
+                }
             }
             else
             {
@@ -257,7 +278,13 @@ JNIEXPORT jstring OLM_INBOUND_GROUP_SESSION_FUNC_DEF(decryptMessageJni)(JNIEnv *
                                                            &messageIndex);
                 if(plaintextLength == olm_error())
                 {
-                    LOGE(" ## decryptMessageJni(): failure - olm_group_decrypt Msg=%s",(const char *)olm_inbound_group_session_last_error(sessionPtr));
+                    errorMsgPtr = olm_inbound_group_session_last_error(sessionPtr);
+                    LOGE(" ## decryptMessageJni(): failure - olm_group_decrypt Msg=%s",errorMsgPtr);
+
+                    if(0 != (errorJstring = env->NewStringUTF(errorMsgPtr)))
+                    {
+                        env->CallObjectMethod(aErrorMsg, errorMsgMethodId, errorJstring);
+                    }
                 }
                 else
                 {
diff --git a/java/android/OlmLibSdk/olm-sdk/src/main/jni/olm_inbound_group_session.h b/java/android/OlmLibSdk/olm-sdk/src/main/jni/olm_inbound_group_session.h
index 7d6fb5e..65ba670 100644
--- a/java/android/OlmLibSdk/olm-sdk/src/main/jni/olm_inbound_group_session.h
+++ b/java/android/OlmLibSdk/olm-sdk/src/main/jni/olm_inbound_group_session.h
@@ -33,7 +33,7 @@ JNIEXPORT jlong OLM_INBOUND_GROUP_SESSION_FUNC_DEF(createNewSessionJni)(JNIEnv *
 
 JNIEXPORT jint OLM_INBOUND_GROUP_SESSION_FUNC_DEF(initInboundGroupSessionWithSessionKeyJni)(JNIEnv *env, jobject thiz, jstring aSessionKey);
 JNIEXPORT jstring OLM_INBOUND_GROUP_SESSION_FUNC_DEF(sessionIdentifierJni)(JNIEnv *env, jobject thiz);
-JNIEXPORT jstring OLM_INBOUND_GROUP_SESSION_FUNC_DEF(decryptMessageJni)(JNIEnv *env, jobject thiz, jstring aEncryptedMsg, jobject aDecryptIndex, jboolean aIsUtf8ConversionRequired);
+JNIEXPORT jstring OLM_INBOUND_GROUP_SESSION_FUNC_DEF(decryptMessageJni)(JNIEnv *env, jobject thiz, jstring aEncryptedMsg, jobject aDecryptIndex, jobject aErrorMsg, jboolean aIsUtf8ConversionRequired);
 
 // serialization
 JNIEXPORT jstring OLM_INBOUND_GROUP_SESSION_FUNC_DEF(serializeDataWithKeyJni)(JNIEnv *env, jobject thiz, jstring aKey, jobject aErrorMsg);