Add Java wrapper for olm_session_describe

Signed-off-by: Alex Baker <alex@beeper.com>

android/olm-sdk/src/androidTest/java/org/matrix/olm/OlmSessionTest.java

@@ -1011,4 +1011,75 @@ public class OlmSessionTest {
         assertTrue(bobSession.isReleased());
     }
 
+    @Test
+    public void test07AliceBobSessionDescribe() {
+        // creates alice & bob accounts
+        OlmAccount aliceAccount = null;
+        OlmAccount bobAccount = null;
+        try {
+            aliceAccount = new OlmAccount();
+            bobAccount = new OlmAccount();
+        } catch (OlmException e) {
+            fail(e.getMessage());
+        }
+
+        // test accounts creation
+        assertTrue(0 != bobAccount.getOlmAccountId());
+        assertTrue(0 != aliceAccount.getOlmAccountId());
+
+        // CREATE ALICE SESSION
+
+        OlmSession aliceSession = null;
+        try {
+            aliceSession = new OlmSession();
+        } catch (OlmException e) {
+            fail("Exception Msg=" + e.getMessage());
+        }
+        assertTrue(0 != aliceSession.getOlmSessionId());
+
+        // CREATE ALICE SESSION
+        OlmSession bobSession = null;
+        try {
+            bobSession = new OlmSession();
+        } catch (OlmException e) {
+            e.printStackTrace();
+            fail(e.getMessage());
+        }
+        assertTrue(0 != bobSession.getOlmSessionId());
+
+        String aliceSessionDescribe = null;
+        try {
+            aliceSessionDescribe = aliceSession.sessionDescribe();
+        } catch (Exception e) {
+            fail(e.getMessage());
+        }
+
+        assertNotNull(aliceSessionDescribe);
+
+        String bobSessionDescribe = null;
+        try {
+            bobSessionDescribe = bobSession.sessionDescribe();
+        } catch (Exception e) {
+            fail(e.getMessage());
+        }
+        assertNotNull(bobSessionDescribe);
+
+        // must be the same for both ends of the conversation
+        assertEquals(aliceSessionDescribe, bobSessionDescribe);
+
+        assertEquals(
+            "sender chain index: 0 receiver chain indices: skipped message keys:",
+            aliceSessionDescribe
+        );
+
+        aliceAccount.releaseAccount();
+        bobAccount.releaseAccount();
+        assertTrue(aliceAccount.isReleased());
+        assertTrue(bobAccount.isReleased());
+
+        bobSession.releaseSession();
+        aliceSession.releaseSession();
+        assertTrue(bobSession.isReleased());
+        assertTrue(aliceSession.isReleased());
+    }
 }

android/olm-sdk/src/main/java/org/matrix/olm/OlmException.java

@@ -60,6 +60,7 @@ public class OlmException extends IOException {
     public static final int EXCEPTION_CODE_SESSION_ENCRYPT_MESSAGE = 404;
     public static final int EXCEPTION_CODE_SESSION_DECRYPT_MESSAGE = 405;
     public static final int EXCEPTION_CODE_SESSION_SESSION_IDENTIFIER = 406;
+    public static final int EXCEPTION_CODE_SESSION_SESSION_DESCRIBE = 407;
 
     public static final int EXCEPTION_CODE_UTILITY_CREATION = 500;
     public static final int EXCEPTION_CODE_UTILITY_VERIFY_SIGNATURE = 501;

android/olm-sdk/src/main/java/org/matrix/olm/OlmSession.java

@@ -223,6 +223,23 @@ public class OlmSession extends CommonSerializeUtils implements Serializable {
      */
     private native byte[] getSessionIdentifierJni();
 
+    public String sessionDescribe() throws OlmException {
+        try {
+            byte[] buffer = olmSessionDescribeJni();
+
+            if (null != buffer) {
+                return new String(buffer, "UTF-8");
+            }
+        } catch (Exception e) {
+            Log.e(LOG_TAG, "## sessionDescribe(): " + e.getMessage());
+            throw new OlmException(OlmException.EXCEPTION_CODE_SESSION_SESSION_DESCRIBE, e.getMessage());
+        }
+
+        return null;
+    }
+
+    private native byte[] olmSessionDescribeJni();
+
     /**
      * Checks if the PRE_KEY({@link OlmMessage#MESSAGE_TYPE_PRE_KEY}) message is for this in-bound session.<br>
      * This API may be used to process a "m.room.encrypted" event when type = 1 (PRE_KEY).

android/olm-sdk/src/main/jni/olm_session.cpp

@@ -798,6 +798,58 @@ JNIEXPORT jbyteArray OLM_SESSION_FUNC_DEF(getSessionIdentifierJni)(JNIEnv *env,
      return returnValue;
 }
 
+JNIEXPORT jbyteArray OLM_SESSION_FUNC_DEF(olmSessionDescribeJni(JNIEnv *env, jobject thiz))
+{
+    const char* errorMessage = NULL;
+    jbyteArray returnValue = 0;
+
+    LOGD("## olmSessionDescribeJni(): IN ");
+
+    OlmSession *sessionPtr = getSessionInstanceId(env, thiz);
+
+    if (!sessionPtr)
+    {
+        LOGE("## olmSessionDescribeJni(): failure - invalid Session ptr=NULL");
+        errorMessage = "invalid Session ptr=NULL";
+    }
+    else
+    {
+        int maxLength = 600;
+        char* describePtr = NULL;
+        describePtr = (char*) malloc(maxLength * sizeof *describePtr);
+        if (!describePtr)
+        {
+            LOGE("## olmSessionDescribeJni(): failure - describe allocation OOM");
+            errorMessage = "describe allocation OOM";
+        }
+        else
+        {
+            olm_session_describe(sessionPtr, describePtr, maxLength);
+            int length = strlen(describePtr);
+            if (length == 0)
+            {
+                LOGE("## olmSessionDescribeJni(): failure - get session describe");
+            }
+            else
+            {
+                LOGD("## olmSessionDescribeJni(): success - describe=%.*s", (char*)describePtr);
+
+                returnValue = env->NewByteArray(length);
+                env->SetByteArrayRegion(returnValue, 0, length, (jbyte*)describePtr);
+            }
+
+            free(describePtr);
+        }
+    }
+
+    if (errorMessage)
+    {
+        env->ThrowNew(env->FindClass("java/lang/Exception"), errorMessage);
+    }
+
+    return returnValue;
+}
+
 /**
  * Serialize and encrypt session instance.<br>
  * An exception is thrown if the operation fails.

android/olm-sdk/src/main/jni/olm_session.h

@@ -47,6 +47,7 @@ JNIEXPORT jbyteArray OLM_SESSION_FUNC_DEF(encryptMessageJni)(JNIEnv *env, jobjec
 JNIEXPORT jbyteArray OLM_SESSION_FUNC_DEF(decryptMessageJni)(JNIEnv *env, jobject thiz, jobject aEncryptedMsg);
 
 JNIEXPORT jbyteArray OLM_SESSION_FUNC_DEF(getSessionIdentifierJni)(JNIEnv *env, jobject thiz);
+JNIEXPORT jbyteArray OLM_SESSION_FUNC_DEF(olmSessionDescribeJni)(JNIEnv *env, jobject thiz);
 
 // serialization
 JNIEXPORT jbyteArray OLM_SESSION_FUNC_DEF(serializeJni)(JNIEnv *env, jobject thiz, jbyteArray aKey);