GlueGen JavaCallback/LibraryOnLoad: Always include the `libraryBasename` agnostic 'emitJNIEnvDecl()' (declaration) in JNI code; Detach the thread from the JVM if newly attach in callback!

3 files changed, 71 insertions, 29 deletions

diff --git a/src/java/com/jogamp/gluegen/CCodeUnit.java b/src/java/com/jogamp/gluegen/CCodeUnit.java
index 5c0db27..6659305 100644
--- a/src/java/com/jogamp/gluegen/CCodeUnit.java
+++ b/src/java/com/jogamp/gluegen/CCodeUnit.java
@@ -50,16 +50,15 @@ public class CCodeUnit extends CodeUnit {
         CodeGenUtils.emitAutogeneratedWarning(output, generator, "C-Unit: "+cUnitName+", "+filename);
     }
 
-    public void emitHeader(final String libraryBasename, final String packageName, final String className, final List<String> customCode) {
+    public void emitHeader(final String packageName, final String className, final List<String> customCode) {
         emitln("#include <jni.h>");
         emitln("#include <stdlib.h>");
         emitln("#include <string.h>");
         emitln("#include <assert.h>");
         emitln("#include <stddef.h>");
         emitln();
-        if( null != libraryBasename && libraryBasename.length() > 0 ) {
-            emitJNIOnLoadJNIEnvDecl(libraryBasename);
-        }
+        emitJNIEnvDecl();
+        emitln();
         emitln("static jobject JVMUtil_NewDirectByteBufferCopy(JNIEnv *env, jclass clazzBuffers, void * source_address, size_t capacity); /* forward decl. */");
         emitln();
 
@@ -74,9 +73,9 @@ public class CCodeUnit extends CodeUnit {
         }
     }
 
-    /** Emits {@link #getJNIOnLoadJNIEnvDecl(String)}. */
-    public void emitJNIOnLoadJNIEnvDecl(final String libraryBasename) {
-        emitln( getJNIOnLoadJNIEnvDecl(libraryBasename) );
+    /** Emits {@link #getJNIEnvDecl()}. */
+    public void emitJNIEnvDecl() {
+        emitln( getJNIEnvDecl() );
     }
 
     /** Emits {@link #getJNIOnLoadJNIEnvCode(String)}. */
@@ -109,28 +108,26 @@ public class CCodeUnit extends CodeUnit {
         "}\n";
 
     /**
-     * Returns native JNI declarations for `JavaVM* {libraryBasename}_jvmHandle`
-     * and `JVMUtil_GetJNIEnv(..)`.
+     * Returns native JNI declarations for `JVMUtil_GetJavaVM()`, `JVMUtil_GetJNIEnv(..)` and `JVMUtil_ReleaseJNIEnv(..)`.
      * <p>
      * See {@link #getJNIOnLoadJNIEnvCode(String)} for details.
      * </p>
-     * @param libraryBasename library basename to generate the `JNI_OnLoad_{libraryBasename}(..)` variant for statically linked libraries.
      * @return the code
      * @see #getJNIOnLoadJNIEnvCode(String)
      */
-    public static final String getJNIOnLoadJNIEnvDecl(final String libraryBasename) {
-        return "extern JavaVM *"+libraryBasename+"_jvmHandle;\n"+
-               "JNIEnv* JVMUtil_GetJNIEnv();\n"+
-               "\n";
+    public static final String getJNIEnvDecl() {
+        return "JavaVM* JVMUtil_GetJavaVM();\n"+
+               "JNIEnv* JVMUtil_GetJNIEnv(int asDaemon, int* jvmAttached);\n"+
+               "void JVMUtil_ReleaseJNIEnv(JNIEnv* env, int detachJVM);\n";
     }
     /**
      * Returns native JNI code `JNI_OnLoad(..)` used for dynamic libraries,
      * `JNI_OnLoad_{libraryBasename}(..)` used for static libraries,
-     * `JVMUtil_GetJNIEnv(..)` and the instance of `JavaVM* {libraryBasename}_jvmHandle`.
+     * `JVMUtil_GetJNIEnv(..)` etc.
      * <p>
-     * The `JNI_OnLoad*(..)` methods set the `JavaVM* {libraryBasename}_jvmHandle`,
+     * The `JNI_OnLoad*(..)` methods set a `static JavaVM* {libraryBasename}_jvmHandle`,
      * which in turn is utilized by `JVMUtil_GetJNIEnv(..)`
-     * to attach a new thread to the `JavaVM*` generating a new `JNIEnv*`in daemon mode -
+     * to attach a new thread to the `JavaVM*` generating a new `JNIEnv*`-
      * or just to retrieve the thread's `JNIEnv*`, if already attached to the `JavaVM*`.
      * </p>
      * @param libraryBasename library basename to generate the `JNI_OnLoad_{libraryBasename}(..)` variant for statically linked libraries.
@@ -140,39 +137,56 @@ public class CCodeUnit extends CodeUnit {
     public static final String getJNIOnLoadJNIEnvCode(final String libraryBasename) {
         final String jvmHandleName = libraryBasename+"_jvmHandle";
         final StringBuilder sb = new StringBuilder();
-        sb.append("JavaVM *").append(jvmHandleName).append(" = NULL;\n");
+        sb.append("static JavaVM *").append(jvmHandleName).append(" = NULL;\n");
+        sb.append("\n");
+        sb.append("JavaVM* JVMUtil_GetJavaVM() {\n");
+        sb.append("  return ").append(jvmHandleName).append(";\n");
+        sb.append("}\n");
         sb.append("JNIEXPORT jint JNICALL JNI_OnLoad(JavaVM *initVM, void *reserved) {\n");
         sb.append("  (void)reserved;\n");
         sb.append("  ").append(jvmHandleName).append(" = initVM;\n");
-        sb.append("  fprintf(stderr, \"ON_LOAD_0\\n\");\n");
+        if( GlueGen.debug() ) {
+            sb.append("  fprintf(stderr, \"ON_LOAD_0 lib '").append(libraryBasename).append("'\\n\");\n");
+        }
         sb.append("  return JNI_VERSION_1_8;\n");
         sb.append("}\n");
         sb.append("JNIEXPORT jint JNICALL JNI_OnLoad_").append(libraryBasename).append("(JavaVM *initVM, void *reserved) {\n");
         sb.append("  (void)reserved;\n");
         sb.append("  ").append(jvmHandleName).append(" = initVM;\n");
-        sb.append("  fprintf(stderr, \"ON_LOAD_1\\n\");\n");
+        if( GlueGen.debug() ) {
+            sb.append("  fprintf(stderr, \"ON_LOAD_1 lib '").append(libraryBasename).append("'\\n\");\n");
+        }
         sb.append("  return JNI_VERSION_1_8;\n");
         sb.append("}\n");
         sb.append("\n");
         sb.append("JNIEXPORT void JNICALL JNI_OnUnload(JavaVM *vm, void *reserved) {\n");
         sb.append("  (void)vm;\n");
         sb.append("  (void)reserved;\n");
-        sb.append("  fprintf(stderr, \"ON_UNLOAD_0\\n\");\n");
+        sb.append("  ").append(jvmHandleName).append(" = NULL;\n");
+        if( GlueGen.debug() ) {
+            sb.append("  fprintf(stderr, \"ON_UNLOAD_0 lib '").append(libraryBasename).append("'\\n\");\n");
+        }
         sb.append("}\n");
         sb.append("\n");
         sb.append("JNIEXPORT void JNICALL JNI_OnUnload_").append(libraryBasename).append("(JavaVM *vm, void *reserved) {\n");
         sb.append("  (void)vm;\n");
         sb.append("  (void)reserved;\n");
-        sb.append("  fprintf(stderr, \"ON_UNLOAD_1\\n\");\n");
+        sb.append("  ").append(jvmHandleName).append(" = NULL;\n");
+        if( GlueGen.debug() ) {
+            sb.append("  fprintf(stderr, \"ON_UNLOAD_1 lib '").append(libraryBasename).append("'\\n\");\n");
+        }
         sb.append("}\n");
         sb.append("\n");
-        sb.append("JNIEnv* JVMUtil_GetJNIEnv() {\n");
+        sb.append("JNIEnv* JVMUtil_GetJNIEnv(int asDaemon, int* jvmAttached) {\n");
         sb.append("    JNIEnv* curEnv = NULL;\n");
         sb.append("    JNIEnv* newEnv = NULL;\n");
         sb.append("    int envRes;\n");
         sb.append("\n");
+        sb.append("    if( NULL != jvmAttached ) {\n");
+        sb.append("      *jvmAttached = 0;\n");
+        sb.append("    }\n");
         sb.append("    if(NULL==").append(jvmHandleName).append(") {\n");
-        sb.append("        fprintf(stderr, \"JVMUtil_GetJNIEnv(").append(libraryBasename).append("): No JavaVM handle registered.\");\n");
+        sb.append("        fprintf(stderr, \"JVMUtil_GetJNIEnv(").append(libraryBasename).append("): No JavaVM handle registered.\\n\");\n");
         sb.append("        return NULL;\n");
         sb.append("    }\n");
         sb.append("\n");
@@ -180,7 +194,11 @@ public class CCodeUnit extends CodeUnit {
         sb.append("    envRes = (*").append(jvmHandleName).append(")->GetEnv(").append(jvmHandleName).append(", (void **) &curEnv, JNI_VERSION_1_8) ;\n");
         sb.append("    if( JNI_EDETACHED == envRes ) {\n");
         sb.append("        // detached thread - attach to JVM as daemon, w/o need to be detached!\n");
-        sb.append("        envRes = (*").append(jvmHandleName).append(")->AttachCurrentThreadAsDaemon(").append(jvmHandleName).append(", (void**) &newEnv, NULL);\n");
+        sb.append("        if( asDaemon ) {\n");
+        sb.append("            envRes = (*").append(jvmHandleName).append(")->AttachCurrentThreadAsDaemon(").append(jvmHandleName).append(", (void**) &newEnv, NULL);\n");
+        sb.append("        } else {\n");
+        sb.append("            envRes = (*").append(jvmHandleName).append(")->AttachCurrentThread(").append(jvmHandleName).append(", (void**) &newEnv, NULL);\n");
+        sb.append("        }\n");
         sb.append("        if( JNI_OK != envRes ) {\n");
         sb.append("            fprintf(stderr, \"JVMUtil_GetJNIEnv(").append(libraryBasename).append("): Can't attach thread: %d\\n\", envRes);\n");
         sb.append("            return NULL;\n");
@@ -195,9 +213,32 @@ public class CCodeUnit extends CodeUnit {
         sb.append("        fprintf(stderr, \"JVMUtil_GetJNIEnv(").append(libraryBasename).append("): env is NULL\\n\");\n");
         sb.append("        return NULL;\n");
         sb.append("    }\n");
+        sb.append("    if( NULL != jvmAttached ) {\n");
+        sb.append("      *jvmAttached = NULL != newEnv;\n");
+        sb.append("    }\n");
+        if( GlueGen.debug() ) {
+            sb.append("    fprintf(stderr, \"JVMUtil_GetJNIEnv(").append(libraryBasename).append(", asDaemon %d): jvmAttached %d -> env %p\\n.\", asDaemon, (NULL != newEnv), curEnv);\n");
+        }
         sb.append("    return curEnv;\n");
         sb.append("}\n");
         sb.append("\n");
+        sb.append("void JVMUtil_ReleaseJNIEnv(JNIEnv* env, int detachJVM) {\n");
+        sb.append("    if(NULL==").append(jvmHandleName).append(") {\n");
+        sb.append("        fprintf(stderr, \"JVMUtil_ReleaseJNIEnv(").append(libraryBasename).append("): No JavaVM handle registered.\\n\");\n");
+        sb.append("        return;\n");
+        sb.append("    }\n");
+        sb.append("    if( detachJVM ) {\n");
+        sb.append("      jint res = (*").append(jvmHandleName).append(")->DetachCurrentThread(").append(jvmHandleName).append(") ;\n");
+        sb.append("      if( 0 != res ) {\n");
+        sb.append("        fprintf(stderr, \"JVMUtil_ReleaseJNIEnv(").append(libraryBasename).append(", env %p): Failed with res %d\\n.\", env, res);\n");
+        sb.append("        return;\n");
+        sb.append("      }\n");
+        if( GlueGen.debug() ) {
+            sb.append("      fprintf(stderr, \"JVMUtil_ReleaseJNIEnv(").append(libraryBasename).append(", env %p) -> res %d\\n.\", env, res);\n");
+        }
+        sb.append("    }\n");
+        sb.append("}\n");
+        sb.append("\n");
         return sb.toString();
     }
 }
diff --git a/src/java/com/jogamp/gluegen/JavaCallbackEmitter.java b/src/java/com/jogamp/gluegen/JavaCallbackEmitter.java
index 96e1e77..b152801 100644
--- a/src/java/com/jogamp/gluegen/JavaCallbackEmitter.java
+++ b/src/java/com/jogamp/gluegen/JavaCallbackEmitter.java
@@ -578,7 +578,8 @@ public final class JavaCallbackEmitter {
         unit.emitln(") {");
         // javaCallback.cbFuncCEmitter.emitBody();
         {
-            unit.emitln("  JNIEnv* env = JVMUtil_GetJNIEnv();");
+            unit.emitln("  int detachJVM = 0;");
+            unit.emitln("  JNIEnv* env = JVMUtil_GetJNIEnv(1 /* daemon */, &detachJVM);");
             unit.emitln("  jclass cbClazz = "+staticBindingClazzVarName+";");
             unit.emitln("  jmethodID cbMethod = "+staticBindingMethodIDVarName+";");
             unit.emitln("  if( NULL == env || NULL == cbClazz || NULL == cbMethod ) {");
@@ -623,7 +624,7 @@ public final class JavaCallbackEmitter {
             // javaCallback.cbFuncCEmitter.emitBodyUserVariableAssignments();
             // javaCallback.cbFuncCEmitter.emitBodyVariablePostCallCleanup();
             // javaCallback.cbFuncCEmitter.emitBodyMapCToJNIType(-1 /* return value */, true /* addLocalVar */)
-
+            unit.emitln("  JVMUtil_ReleaseJNIEnv(env, detachJVM);");
             unit.emitln("  "+returnStatement);
         }
         unit.emitln("}");
diff --git a/src/java/com/jogamp/gluegen/JavaEmitter.java b/src/java/com/jogamp/gluegen/JavaEmitter.java
index 4a81a01..96202bf 100644
--- a/src/java/com/jogamp/gluegen/JavaEmitter.java
+++ b/src/java/com/jogamp/gluegen/JavaEmitter.java
@@ -910,7 +910,7 @@ public class JavaEmitter implements GlueEmitter {
             final String fname = nRoot + File.separator + cUnitName;
             jniUnit = openCUnit(fname, cUnitName);
             // jniUnit.emitHeader(structClassPkgName, containingJTypeName, Collections.emptyList());
-            jniUnit.emitHeader(null, structClassPkgName, containingJTypeName, cfg.customCCode());
+            jniUnit.emitHeader(structClassPkgName, containingJTypeName, cfg.customCCode());
         } else {
             jniUnit = null;
         }
@@ -3018,7 +3018,7 @@ public class JavaEmitter implements GlueEmitter {
         if( !cfg.getJavaCallbackList().isEmpty() && null == cfg.libraryOnLoadName() ) {
             LOG.log(WARNING, "JavaCallback used, but no 'LibraryOnLoad' basename specified for JNI_OnLoad(..). Exactly one native code-unit for the library must specify 'LibraryOnLoad' basename");
         }
-        cUnit().emitHeader(cfg.libraryOnLoadName(), getImplPackageName(), cfg.implClassName(), cfg.customCCode());
+        cUnit().emitHeader(getImplPackageName(), cfg.implClassName(), cfg.customCCode());
       }
     } catch (final Exception e) {
       throw new RuntimeException(