android: Add support for callbacks from LO to JNI and Java LOK

This adds support to retrieve callbacks from LibreOffice (like
for example that a part of document has been invalidated) to
LibreOfficeKit JNI and Java wrappers.

Change-Id: Ib70187194d002c72b64d58032aab216adc591565

2 files changed, 85 insertions, 0 deletions

diff --git a/android/Bootstrap/src/org/libreoffice/kit/Document.java b/android/Bootstrap/src/org/libreoffice/kit/Document.java
index e415d8f1605a..6985a7c206a2 100644
--- a/android/Bootstrap/src/org/libreoffice/kit/Document.java
+++ b/android/Bootstrap/src/org/libreoffice/kit/Document.java
@@ -9,6 +9,8 @@
 
 package org.libreoffice.kit;
 
+import android.util.Log;
+
 import java.nio.ByteBuffer;
 
 public class Document {
@@ -28,8 +30,22 @@ public class Document {
 
     public Document(ByteBuffer handle) {
         this.handle = handle;
+        bindMessageCallback();
+    }
+
+    /**
+     * Callback triggered through JNI to indicate that a new singal
+     * from LibreOfficeKit was retrieved.
+     */
+    private void messageRetrieved(int signalNumber, String payload) {
+        Log.i("Document", "Signal retrieved: " + signalNumber + " " + payload);
     }
 
+    /**
+     * Bind the signal callback in LOK.
+     */
+    private native void bindMessageCallback();
+
     public native void destroy();
 
     public native int getPart();
diff --git a/desktop/source/lib/lokandroid.cxx b/desktop/source/lib/lokandroid.cxx
index 2b18071e6b94..06da8a97d423 100644
--- a/desktop/source/lib/lokandroid.cxx
+++ b/desktop/source/lib/lokandroid.cxx
@@ -22,6 +22,9 @@
 
 /* LibreOfficeKit */
 
+namespace
+{
+
 jfieldID getHandleField(JNIEnv* pEnv, jobject aObject)
 {
     jclass clazz = pEnv->GetObjectClass(aObject);
@@ -46,6 +49,8 @@ const char* copyJavaString(JNIEnv* pEnv, jstring aJavaString)
     return pClone;
 }
 
+} // anonymous namespace
+
 extern "C" SAL_JNI_EXPORT jstring JNICALL Java_org_libreoffice_kit_Office_getError(JNIEnv* pEnv, jobject aObject)
 {
     LibreOfficeKit* pLibreOfficeKit = getHandle<LibreOfficeKit>(pEnv, aObject);
@@ -68,6 +73,55 @@ extern "C" SAL_JNI_EXPORT void JNICALL Java_org_libreoffice_kit_Office_destroyAn
     _exit(0);
 }
 
+namespace
+{
+
+struct CallbackData
+{
+    jmethodID aJavaCallbackMethod;
+    jclass aClass;
+    jobject aObject;
+};
+
+static CallbackData gCallbackData;
+
+/**
+ * Handle retrieved callback
+ */
+void messageCallback(int nType, const char* pPayload, void* pData)
+{
+    CallbackData* pCallbackData = (CallbackData*) pData;
+
+    JavaVM* pJavaVM = lo_get_javavm();
+    JNIEnv* pEnv;
+    bool bIsAttached = false;
+
+    int status = pJavaVM->GetEnv((void **) &pEnv, JNI_VERSION_1_6);
+
+    if(status < 0)
+    {
+        status = pJavaVM->AttachCurrentThread(&pEnv, NULL);
+        if(status < 0)
+        {
+            return;
+        }
+        bIsAttached = true;
+    }
+
+    jvalue aParameter[2];
+    aParameter[0].i = nType;
+    aParameter[1].l = pEnv->NewStringUTF(pPayload);
+
+    pEnv->CallVoidMethodA(pCallbackData->aObject, pCallbackData->aJavaCallbackMethod, aParameter);
+
+    if (bIsAttached)
+    {
+        pJavaVM->DetachCurrentThread();
+    }
+}
+
+} // anonymous namespace
+
 extern "C" SAL_JNI_EXPORT jobject JNICALL Java_org_libreoffice_kit_Office_documentLoadNative(JNIEnv* pEnv, jobject aObject, jstring documentPath)
 {
     const char* aCloneDocumentPath = copyJavaString(pEnv, documentPath);
@@ -81,6 +135,21 @@ extern "C" SAL_JNI_EXPORT jobject JNICALL Java_org_libreoffice_kit_Office_docume
 
 /* Document */
 
+/** Implementation of org.libreoffice.kit.Document.bindMessageCallback method */
+extern "C" SAL_JNI_EXPORT void JNICALL Java_org_libreoffice_kit_Document_bindMessageCallback
+    (JNIEnv* pEnv, jobject aObject)
+{
+    LibreOfficeKitDocument* pDocument = getHandle<LibreOfficeKitDocument>(pEnv, aObject);
+
+    gCallbackData.aObject = (jobject) pEnv->NewGlobalRef(aObject);
+    jclass aClass = pEnv->GetObjectClass(aObject);
+    gCallbackData.aClass = (jclass) pEnv->NewGlobalRef(aClass);
+
+    gCallbackData.aJavaCallbackMethod = pEnv->GetMethodID(aClass, "messageRetrieved", "(ILjava/lang/String;)V");
+
+    pDocument->pClass->registerCallback(pDocument, messageCallback, (void*) &gCallbackData);
+}
+
 extern "C" SAL_JNI_EXPORT void JNICALL Java_org_libreoffice_kit_Document_destroy
     (JNIEnv* pEnv, jobject aObject)
 {