GlueGen JavaCallback: Revised: Static Java callback dispatcher, dropping native heap, support Struct UserParam ...

Implementation now generates a static Java callback dispatcher for each defined SetCallbackFunction, which gets invoked by the generated native static counterpart with all arguments required.

The static callback utilizes its own synchronization for thread-safety and fetches the required data set stored at SetCallbackFunction to dispatch the call to the users' CallbackFunction.
In case the callback has been removed already, the static callback simply bails out quietly.

The native code does not create, release or manage heap memory and therefore is considered safe.

+++

Further Struct Type UserParam are now supported including Heterogeneous UserParam mapping (read GlueGen_Mapping.*).

+++

Cleaned up code by extracting all JavaCallback emitter code into JavaCallbackEmitter class in one place,
leaving JavaMethodbindingEmitter and CMethodbindingEmitter mostly in their original stage (non-convoluted).

In this regard, I had to refactor a few function, i.e. moving CMethodbindingEmitter.getJNIMangledArg(..)
into JavaType.appendDescriptor(..) and JavaType.appendJNIDescriptor(..) while reusing the toJNIMethodDescriptor(..) conversion.

Test4JavaCallback covers and passes all cases.

1 files changed, 666 insertions, 0 deletions

diff --git a/src/java/com/jogamp/gluegen/JavaCallbackEmitter.java b/src/java/com/jogamp/gluegen/JavaCallbackEmitter.java
new file mode 100644
index 0000000..96e1e77
--- /dev/null
+++ b/src/java/com/jogamp/gluegen/JavaCallbackEmitter.java
@@ -0,0 +1,666 @@
+/**
+ * Copyright 2023 JogAmp Community. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification, are
+ * permitted provided that the following conditions are met:
+ *
+ *    1. Redistributions of source code must retain the above copyright notice, this list of
+ *       conditions and the following disclaimer.
+ *
+ *    2. Redistributions in binary form must reproduce the above copyright notice, this list
+ *       of conditions and the following disclaimer in the documentation and/or other materials
+ *       provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY JogAmp Community ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL JogAmp Community OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * The views and conclusions contained in the software and documentation are those of the
+ * authors and should not be interpreted as representing official policies, either expressed
+ * or implied, of JogAmp Community.
+ */
+package com.jogamp.gluegen;
+
+import com.jogamp.gluegen.JavaConfiguration.JavaCallbackInfo;
+import com.jogamp.gluegen.cgram.types.Type;
+
+public final class JavaCallbackEmitter {
+    final JavaConfiguration cfg;
+    final MethodBinding binding;
+    final String setFuncSignature;
+    final JavaCallbackInfo info;
+    final String capIfaceName;
+    final String lowIfaceName;
+    final String lockInstanceName;
+    final String dataMapInstanceName;
+    final String dataInstanceName;
+    final String DataClassName;
+    final String fqUsrParamClassName;
+    final JavaType cbFuncJavaReturnType;
+    final String jcbNextIDVarName;
+
+    final String setFuncCBArgName;
+    final Type setFuncUserParamCType;
+    final JavaType setFuncUserParamJType;
+    final String setFuncUserParamTypeName;
+    final String setFuncUserParamArgName;
+
+    final boolean customKeyClass;
+    final String KeyClassName;
+    final boolean useDataMap;
+
+    public JavaCallbackEmitter(final JavaConfiguration cfg, final MethodBinding mb, final JavaCallbackInfo javaCallback, final String setFuncSignature) {
+        this.cfg = cfg;
+        this.binding = mb;
+        this.setFuncSignature = setFuncSignature;
+        this.info = javaCallback;
+
+        capIfaceName = CodeGenUtils.capitalizeString( mb.getInterfaceName() );
+        lowIfaceName = CodeGenUtils.decapitalizeString( mb.getInterfaceName() );
+        lockInstanceName = lowIfaceName+"Lock";
+        dataMapInstanceName = lowIfaceName+"DataMap";
+        dataInstanceName = lowIfaceName+"Data";
+        DataClassName = capIfaceName+"Data";
+        fqUsrParamClassName = cfg.packageName()+"."+cfg.className()+"."+DataClassName;
+        cbFuncJavaReturnType = javaCallback.cbFuncBinding.getJavaReturnType();
+        jcbNextIDVarName = "NEXT_"+capIfaceName+"_ID";
+
+        setFuncCBArgName = binding.getArgumentName(javaCallback.setFuncCBParamIdx);
+        setFuncUserParamCType = mb.getCArgumentType(javaCallback.setFuncUserParamIdx);
+        setFuncUserParamJType = mb.getJavaArgumentType(javaCallback.setFuncUserParamIdx);
+        setFuncUserParamTypeName = setFuncUserParamJType.getName();
+        setFuncUserParamArgName = binding.getArgumentName(javaCallback.setFuncUserParamIdx);
+
+        if( null != javaCallback.setFuncKeyClassName ) {
+            customKeyClass = true;;
+            KeyClassName = javaCallback.setFuncKeyClassName;
+            useDataMap = true;
+        } else {
+            customKeyClass = false;
+            KeyClassName = capIfaceName+"Key";
+            useDataMap = javaCallback.setFuncKeyIndices.size() > 0;
+        }
+    }
+
+    public void emitJavaSetFuncPreCall(final CodeUnit unit) {
+        unit.emitln("    synchronized( "+lockInstanceName+" ) {");
+        unit.emit  ("      final long nativeUserParam = ");
+        if( setFuncUserParamJType.isLong() ) {
+            unit.emitln(" "+setFuncUserParamArgName+";");
+        } else if( setFuncUserParamJType.isCompoundTypeWrapper() ) {
+            unit.emitln(" null != "+setFuncUserParamArgName+" ? "+setFuncUserParamArgName+".getDirectBufferAddress() : 0;");
+        } else {
+            unit.emitln(""+jcbNextIDVarName+"++;");
+            unit.emitln("      if( 0 >= "+jcbNextIDVarName+" ) { "+jcbNextIDVarName+" = 1; }");
+        }
+        unit.emitln("      if( null != "+setFuncCBArgName+" ) {");
+        unit.emitln("        add"+capIfaceName+"("+binding.getJavaCallSelectArguments(new StringBuilder(), info.setFuncKeyIndices, true).toString()+
+                "new "+DataClassName+"("+setFuncCBArgName+", "+setFuncUserParamArgName+"));");
+        unit.emitln("      }");
+        unit.emitln();
+    }
+
+    public void emitJavaSetFuncPostCall(final CodeUnit unit) {
+        unit.emitln("      if( null == "+setFuncCBArgName+" ) {");
+        unit.emitln("          // callback released (null func) -> release a previously mapped instance ");
+        if( useDataMap ) {
+            unit.emitln("          release"+capIfaceName+"( new "+KeyClassName+"( "+binding.getJavaCallSelectArguments(new StringBuilder(), info.setFuncKeyIndices, false).toString()+" ) );");
+        } else {
+            unit.emitln("          release"+capIfaceName+"();");
+        }
+        unit.emitln("      }");
+        unit.emitln("    } // synchronized ");
+    }
+
+    public void emitJavaAdditionalCode(final CodeUnit unit, final boolean isInterface) {
+        if( isInterface ) {
+            if( useDataMap ) {
+                if( !customKeyClass && !info.keyClassEmitted ) {
+                    emitJavaKeyClass(unit);
+                    unit.emitln();
+                    info.keyClassEmitted = true;
+                }
+                emitJavaBriefAPIDoc(unit, "Returns ", "set of ", "", "for ");
+                unit.emitln("  public Set<"+KeyClassName+"> get"+capIfaceName+"Keys();");
+                unit.emitln();
+                emitJavaBriefAPIDoc(unit, "Returns ", "whether callback ", "if callback ", "is mapped for ");
+                unit.emitln("  public boolean is"+capIfaceName+"Mapped("+KeyClassName+" key);");
+                unit.emitln();
+                emitJavaBriefAPIDoc(unit, "Returns "+info.cbFuncTypeName+" callback ", "mapped to ", "", "for ");
+                unit.emitln("  public "+info.cbFuncTypeName+" get"+capIfaceName+"("+KeyClassName+" key);");
+                unit.emitln();
+                emitJavaBriefAPIDoc(unit, "Returns user-param ", "mapped to ", "", "for ");
+                unit.emitln("  public Object get"+capIfaceName+"UserParam("+KeyClassName+" key);");
+                unit.emitln();
+                emitJavaBriefAPIDoc(unit, "Releases all callback data ", "mapped via ", "", "skipping toolkit API. Favor passing `null` callback ref to ");
+                unit.emitln("  public int releaseAll"+capIfaceName+"();");
+                unit.emitln();
+                emitJavaBriefAPIDoc(unit, "Releases callback data ", "mapped to ", "", "skipping toolkit API. Favor passing `null` callback ref to ");
+                unit.emitln("  public void release"+capIfaceName+"("+KeyClassName+" key);");
+                unit.emitln();
+            } else {
+                emitJavaBriefAPIDoc(unit, "Returns ", "whether callback ", "if callback ", "is mapped for ");
+                unit.emitln("  public boolean is"+capIfaceName+"Mapped();");
+                unit.emitln();
+                emitJavaBriefAPIDoc(unit, "Returns "+info.cbFuncTypeName+" callback ", "mapped to ", "", "for ");
+                unit.emitln("  public "+info.cbFuncTypeName+" get"+capIfaceName+"();");
+                unit.emitln();
+                emitJavaBriefAPIDoc(unit, "Returns user-param ", "mapped to ", "", "for ");
+                unit.emitln("  public Object get"+capIfaceName+"UserParam();");
+                unit.emitln();
+                emitJavaBriefAPIDoc(unit, "Releases callback data ", "", "", "skipping toolkit API. Favor passing `null` callback ref to ");
+                unit.emitln("  public void release"+capIfaceName+"();");
+                unit.emitln();
+            }
+        } else {
+            if( useDataMap ) {
+                if( !customKeyClass && !info.keyClassEmitted ) {
+                    emitJavaKeyClass(unit);
+                    unit.emitln();
+                    info.keyClassEmitted = true;
+                }
+                emitJavaBriefAPIDoc(unit, "Returns ", "set of ", "", "for ");
+                unit.emitln("  public final Set<"+KeyClassName+"> get"+capIfaceName+"Keys() {");
+                unit.emitln("    synchronized( "+lockInstanceName+" ) {");
+                unit.emitln("      return "+dataMapInstanceName+".keySet();");
+                unit.emitln("    }");
+                unit.emitln("  }");
+                unit.emitln();
+                emitJavaBriefAPIDoc(unit, "Returns ", "whether callback ", "if callback ", "is mapped for ");
+                unit.emitln("  public final boolean is"+capIfaceName+"Mapped("+KeyClassName+" key) {");
+                unit.emitln("    synchronized( "+lockInstanceName+" ) {");
+                unit.emitln("      return null != "+dataMapInstanceName+".get(key);");
+                unit.emitln("    }");
+                unit.emitln("  }");
+                unit.emitln();
+
+                emitJavaBriefAPIDoc(unit, "Returns "+info.cbFuncTypeName+" callback ", "mapped to ", "", "for ");
+                unit.emitln("  public final "+info.cbFuncTypeName+" get"+capIfaceName+"("+KeyClassName+" key) {");
+                unit.emitln("    synchronized( "+lockInstanceName+" ) {");
+                unit.emitln("      final "+DataClassName+" value = "+dataMapInstanceName+".get(key);");
+                unit.emitln("      return null != value ? value.func : null;");
+                unit.emitln("    }");
+                unit.emitln("  }");
+                unit.emitln();
+
+                emitJavaBriefAPIDoc(unit, "Returns user-param ", "mapped to ", "", "for ");
+                unit.emitln("  public final Object get"+capIfaceName+"UserParam("+KeyClassName+" key) {");
+                unit.emitln("    synchronized( "+lockInstanceName+" ) {");
+                unit.emitln("      final "+DataClassName+" value = "+dataMapInstanceName+".get(key);");
+                unit.emitln("      return null != value ? value.param : null;");
+                unit.emitln("    }");
+                unit.emitln("  }");
+                unit.emitln();
+                emitJavaBriefAPIDoc(unit, "Releases all callback data ", "mapped via ", "", "skipping toolkit API. Favor passing `null` callback ref to ");
+                unit.emitln("  public final int releaseAll"+capIfaceName+"() {");
+                unit.emitln("    synchronized( "+lockInstanceName+" ) {");
+                unit.emitln("      final Set<"+KeyClassName+"> keySet = "+dataMapInstanceName+".keySet();");
+                unit.emitln("      final "+KeyClassName+"[] keys = keySet.toArray(new "+KeyClassName+"[keySet.size()]);");
+                unit.emitln("      for(int i=0; i<keys.length; ++i) {");
+                unit.emitln("        final "+KeyClassName+" key = keys[i];");
+                unit.emitln("          release"+capIfaceName+"(key);");
+                unit.emitln("      }");
+                unit.emitln("      return keys.length;");
+                unit.emitln("    }");
+                unit.emitln("  }");
+                unit.emitln();
+                emitJavaBriefAPIDoc(unit, "Releases callback data ", "mapped to ", "", "skipping toolkit API. Favor passing `null` callback ref to ");
+                unit.emitln("  public final void release"+capIfaceName+"("+KeyClassName+" key) {");
+                unit.emitln("    synchronized( "+lockInstanceName+" ) {");
+                unit.emitln("      /* final "+DataClassName+" value = */ "+dataMapInstanceName+".remove(key);");
+                unit.emitln("    }");
+                unit.emitln("  }");
+                unit.emitln();
+            } else {
+                emitJavaBriefAPIDoc(unit, "Returns ", "whether callback ", "if callback ", "is mapped for ");
+                unit.emitln("  public final boolean is"+capIfaceName+"Mapped() {");
+                unit.emitln("    synchronized( "+lockInstanceName+" ) {");
+                unit.emitln("      return null != "+dataInstanceName+";");
+                unit.emitln("    }");
+                unit.emitln("  }");
+                unit.emitln();
+
+                emitJavaBriefAPIDoc(unit, "Returns "+info.cbFuncTypeName+" callback ", "mapped to ", "", "for ");
+                unit.emitln("  public final "+info.cbFuncTypeName+" get"+capIfaceName+"() {");
+                unit.emitln("    synchronized( "+lockInstanceName+" ) {");
+                unit.emitln("      final "+DataClassName+" value = "+dataInstanceName+";");
+                unit.emitln("      return null != value ? value.func : null;");
+                unit.emitln("    }");
+                unit.emitln("  }");
+                unit.emitln();
+
+                emitJavaBriefAPIDoc(unit, "Returns user-param ", "mapped to ", "", "for ");
+                unit.emitln("  public final Object get"+capIfaceName+"UserParam() {");
+                unit.emitln("    synchronized( "+lockInstanceName+" ) {");
+                unit.emitln("      final "+DataClassName+" value = "+dataInstanceName+";");
+                unit.emitln("      return null != value ? value.param : null;");
+                unit.emitln("    }");
+                unit.emitln("  }");
+                unit.emitln();
+
+                emitJavaBriefAPIDoc(unit, "Releases callback data ", "", "", "skipping toolkit API. Favor passing `null` callback ref to ");
+                unit.emitln("  public final void release"+capIfaceName+"() {");
+                unit.emitln("    synchronized( "+lockInstanceName+" ) {");
+                unit.emitln("      // final "+DataClassName+" value = "+dataInstanceName+";");
+                unit.emitln("      "+dataInstanceName+" = null;");
+                unit.emitln("    }");
+                unit.emitln("  }");
+                unit.emitln();
+            }
+            unit.emitln("  private final void add"+capIfaceName+"("+binding.getJavaSelectParameter(new StringBuilder(), info.setFuncKeyIndices, true).toString()+DataClassName+" value) {");
+            if( useDataMap ) {
+                unit.emitln("    final "+KeyClassName+" key = new "+KeyClassName+"("+binding.getJavaCallSelectArguments(new StringBuilder(), info.setFuncKeyIndices, false).toString()+");");
+                unit.emitln("    /* final "+DataClassName+" old = */ "+dataMapInstanceName+".put(key, value);");
+            } else {
+                unit.emitln("    // final "+DataClassName+" old = "+dataInstanceName+";");
+                unit.emitln("    "+dataInstanceName+" = value;");
+            }
+            unit.emitln("  }");
+            unit.emitln();
+            if( !cfg.emittedJavaCallbackUserParamClasses.contains(fqUsrParamClassName) ) {
+                emitJavaDataClass(unit);
+                cfg.emittedJavaCallbackUserParamClasses.add(fqUsrParamClassName);
+            }
+            if( useDataMap ) {
+                unit.emitln("  private static final Map<"+KeyClassName+", "+DataClassName+"> "+dataMapInstanceName+" = new HashMap<"+KeyClassName+", "+DataClassName+">();");
+            } else {
+                unit.emitln("  private static "+DataClassName+" "+dataInstanceName+" = null;");
+            }
+            unit.emitln("  private static long "+jcbNextIDVarName+" = 1;");
+            unit.emitln("  private static final Object "+lockInstanceName+" = new Object();");
+            unit.emitln();
+            emitJavaStaticCallback(unit);
+        }
+    }
+
+    private final void emitJavaBriefAPIDoc(final CodeUnit unit, final String actionText, final String relationToKey, final String noKeyText, final String relationToFunc) {
+        unit.emit("  /** "+actionText);
+        if( info.setFuncKeyIndices.size() > 0 ) {
+            unit.emit(relationToKey);
+            unit.emit("Key { "+binding.getJavaSelectParameter(new StringBuilder(), info.setFuncKeyIndices, false).toString()+" } ");
+        } else {
+            unit.emit(noKeyText);
+        }
+        unit.emit(relationToFunc);
+        unit.emitln("<br> <code>"+setFuncSignature+"</code> */");
+    }
+
+    private final void emitJavaKeyClass(final CodeUnit unit) {
+        emitJavaBriefAPIDoc(unit, "", "", "", "for ");
+        unit.emitln("  public static class "+KeyClassName+" {");
+        binding.forEachParameter( ( final int idx, final int consumedCount, final Type cType, final JavaType jType, final String name ) -> {
+            if( !cType.isVoid() && info.setFuncKeyIndices.contains(idx) ) {
+                unit.emitln("    public final "+jType+" "+name+";");
+                return true;
+            } else {
+                return false;
+            }
+        } );
+        unit.emitln("    public "+KeyClassName+"("+binding.getJavaSelectParameter(new StringBuilder(), info.setFuncKeyIndices, false).toString()+") {");
+        binding.forEachParameter( ( final int idx, final int consumedCount, final Type cType, final JavaType jType, final String name ) -> {
+            if( !cType.isVoid() && info.setFuncKeyIndices.contains(idx) ) {
+                unit.emitln("      this."+name+" = "+name+";");
+                return true;
+            } else {
+                return false;
+            }
+        } );
+        unit.emitln("    }");
+        unit.emitln("    @Override");
+        unit.emitln("    public boolean equals(final Object o) {");
+        unit.emitln("      if( this == o ) {");
+        unit.emitln("        return true;");
+        unit.emitln("      }");
+        unit.emitln("      if( !(o instanceof "+KeyClassName+") ) {");
+        unit.emitln("        return false;");
+        unit.emitln("      }");
+        {
+            final int count = binding.forEachParameter( ( final int idx, final int consumedCount, final Type cType, final JavaType jType, final String name ) -> {
+                if( !cType.isVoid() && info.setFuncKeyIndices.contains(idx) ) {
+                    if( 0 == consumedCount ) {
+                        unit.emitln("      final "+KeyClassName+" o2 = ("+KeyClassName+")o;");
+                        unit.emit  ("      return ");
+                    } else {
+                        unit.emitln(" &&");
+                        unit.emit  ("             ");
+                    }
+                    if( jType.isPrimitive() || idx == info.setFuncUserParamIdx ) {
+                        unit.emit(name+" == o2."+name);
+                    } else {
+                        unit.emit(name+".equals( o2."+name+" )");
+                    }
+                    return true;
+                } else {
+                    return false;
+                }
+            } );
+            if( 0 == count ) {
+                unit.emit("      return true");
+            }
+            unit.emitln(";");
+        }
+        unit.emitln("    }");
+        unit.emitln("    @Override");
+        unit.emitln("    public int hashCode() {");
+        {
+            final int count = binding.forEachParameter( ( final int idx, final int consumedCount, final Type cType, final JavaType jType, final String name ) -> {
+                if( !cType.isVoid() && info.setFuncKeyIndices.contains(idx) ) {
+                    if( 0 == consumedCount ) {
+                        unit.emitln("      // 31 * x == (x << 5) - x");
+                        unit.emit  ("      int hash = ");
+                    } else {
+                        unit.emit  ("      hash = ((hash << 5) - hash) + ");
+                    }
+                    if( jType.isPrimitive() ) {
+                        if( jType.isLong() ) {
+                            unit.emitln("HashUtil.getAddrHash32_EqualDist( "+name+" );");
+                        } else {
+                            unit.emitln(name+";");
+                        }
+                    } else {
+                        if( idx == info.setFuncUserParamIdx ) {
+                            unit.emitln("System.identityHashCode( "+name+" );");
+                        } else {
+                            unit.emitln(name+".hashCode();");
+                        }
+                    }
+                    return true;
+                } else {
+                    return false;
+                }
+            } );
+            if( 0 == count ) {
+                unit.emitln("      return 0;");
+            } else {
+                unit.emitln("      return hash;");
+            }
+        }
+        unit.emitln("    }");
+        unit.emitln("  }");
+    }
+
+    private final void emitJavaDataClass(final CodeUnit unit) {
+        unit.emitln("  private static class "+DataClassName+" {");
+        unit.emitln("    // userParamArgCType "+setFuncUserParamCType);
+        unit.emitln("    // userParamArgJType "+setFuncUserParamJType);
+        unit.emitln("    final "+info.cbFuncTypeName+" func;");
+        unit.emitln("    final "+setFuncUserParamTypeName+" param;");
+        unit.emitln("    "+DataClassName+"("+info.cbFuncTypeName+" func, "+setFuncUserParamTypeName+" param) {");
+        unit.emitln("      this.func = func;");
+        unit.emitln("      this.param = param;");
+        unit.emitln("    }");
+        unit.emitln("  }");
+    }
+
+    public final String getJavaStaticCallbackSignature() {
+        final StringBuilder buf = new StringBuilder();
+        buf.append("(");
+        info.cbFuncBinding.forEachParameter( ( final int idx, final int consumedCount, final Type cType, final JavaType jType, final String name ) -> {
+            if( !cType.isVoid() ) {
+                if( idx == info.cbFuncUserParamIdx ) {
+                    buf.append("J");
+                } else {
+                    buf.append(jType.getDescriptor());
+                }
+                return true;
+            } else {
+                return false;
+            }
+        } );
+        buf.append(")");
+        buf.append(cbFuncJavaReturnType.getDescriptor());
+        return buf.toString();
+    }
+
+    public final int appendJavaAdditionalJNIParameter(final StringBuilder buf) {
+        buf.append("Class<?> clazz, String callbackSignature, long nativeUserParam");
+        return 3;
+    }
+    public final int appendJavaAdditionalJNIArguments(final StringBuilder buf) {
+        buf.append("this.getClass(), \"" + getJavaStaticCallbackSignature()+ "\", nativeUserParam");
+        return 3;
+    }
+    private final void emitJavaStaticCallback(final CodeUnit unit) {
+        unit.emitln("  /** Static callback invocation, dispatching to "+info.cbSimpleClazzName+" for callback <br> <code>"+
+                info.cbFuncType.toString(info.cbFuncTypeName, false, true)+"</code> */");
+        unit.emit  ("  /* pp */ static "+cbFuncJavaReturnType.getName()+" invoke"+capIfaceName+"(");
+        final boolean[] mapNativePtrToCompound = { false };
+        final JavaType[] origUserParamJType = { null };
+        info.cbFuncBinding.forEachParameter( ( final int idx, final int consumedCount, final Type cType, final JavaType jType, final String name ) -> {
+            if( !cType.isVoid() ) {
+                if( 0 < consumedCount ) { unit.emit(", "); }
+                if( idx == info.cbFuncUserParamIdx ) {
+                    unit.emit("long nativeUserParamPtr");
+                    if( jType.isCompoundTypeWrapper() ) {
+                        mapNativePtrToCompound[0] = true;
+                        origUserParamJType[0] = jType;
+                    }
+                } else {
+                    unit.emit(jType+" "+name);
+                }
+                return true;
+            } else {
+                return false;
+            }
+        } );
+        unit.emitln(") {");
+        if( mapNativePtrToCompound[0] ) {
+            unit.emitln("    final "+origUserParamJType[0]+" "+info.cbFuncUserParamName+" = "+origUserParamJType[0]+".derefPointer(nativeUserParamPtr);");
+        }
+        if( useDataMap ) {
+            unit.emitln("    final "+DataClassName+" value;");
+        } else {
+            unit.emitln("    final "+DataClassName+" value;");
+        }
+        unit.emitln("    synchronized( "+lockInstanceName+" ) {");
+        if( useDataMap ) {
+            unit.emitln("      final "+KeyClassName+" key = new "+KeyClassName+"("+binding.getJavaCallSelectArguments(new StringBuilder(), info.setFuncKeyIndices, false).toString()+");");
+            unit.emitln("      value = "+dataMapInstanceName+".get(key);");
+        } else {
+            unit.emitln("      value = "+dataInstanceName+";");
+        }
+        unit.emitln("    }");
+        unit.emitln("    if( null == value ) {");
+        if( !cbFuncJavaReturnType.isVoid() ) {
+            unit.emitln("      return 0;");
+        } else {
+            unit.emitln("      return;");
+        }
+        unit.emitln("    }");
+        if( !cbFuncJavaReturnType.isVoid() ) {
+            unit.emit("    return ");
+        } else {
+            unit.emit("    ");
+        }
+        unit.emit("value.func.callback(");
+        info.cbFuncBinding.forEachParameter( ( final int idx, final int consumedCount, final Type cType, final JavaType jType, final String name ) -> {
+            if( !cType.isVoid() ) {
+                if( 0 < consumedCount ) { unit.emit(", "); }
+                if( idx == info.cbFuncUserParamIdx && !mapNativePtrToCompound[0] ) {
+                    unit.emit("value.param");
+                } else {
+                    unit.emit(name);
+                }
+                return true;
+            } else {
+                return false;
+            }
+        } );
+        unit.emitln(");");
+        unit.emitln("  }");
+        unit.emitln();
+    }
+
+    //
+    // C JNI Code ..
+    //
+
+    public int appendCAdditionalParameter(final StringBuilder buf) {
+        buf.append(", jclass clazz, jstring jcallbackSignature, jlong jnativeUserParam");
+        return 3;
+    }
+
+    public void emitCOptArgumentSuffix(final CodeUnit unit, final int argIdx) {
+      if( ( argIdx == info.setFuncCBParamIdx || argIdx == info.setFuncUserParamIdx ) ) {
+          unit.emit("_native");
+      }
+    }
+
+    public void appendCAdditionalJNIDescriptor(final StringBuilder buf) {
+        JavaType.appendJNIDescriptor(buf, Class.class, false);  // to account for the additional 'jclass clazz' parameter
+        JavaType.appendJNIDescriptor(buf, String.class, false);  // to account for the additional 'jstring jcallbackSignature' parameter
+        JavaType.appendJNIDescriptor(buf, long.class, false);  // to account for the additional 'long nativeUserParam' parameter
+    }
+
+    public void emitCSetFuncPreCall(final CodeUnit unit) {
+        final String jcbNativeBasename = CodeGenUtils.capitalizeString( info.setFuncName );
+        final String jcbFriendlyBasename = info.setFuncName+"("+info.cbSimpleClazzName+")";
+        final String staticBindingMethodName = "invoke"+jcbNativeBasename;
+        final String staticBindingClazzVarName = "clazz"+jcbNativeBasename;
+        final String staticBindingMethodIDVarName = "method"+jcbNativeBasename;
+        final String cbFuncArgName = binding.getArgumentName(info.setFuncCBParamIdx);
+        final String userParamTypeName = info.cbFuncUserParamType.getCName();
+        final String userParamArgName = binding.getArgumentName(info.setFuncUserParamIdx);
+        final String nativeCBFuncVarName = cbFuncArgName+"_native";
+        final String nativeUserParamVarName = userParamArgName+"_native";
+        unit.emitln();
+        unit.emitln("  // JavaCallback handling");
+        unit.emitln("  if( NULL == clazz ) { (*env)->FatalError(env, \"NULL clazz passed to '"+jcbFriendlyBasename+"'\"); }");
+        unit.emitln("  "+info.cbFuncTypeName+" "+nativeCBFuncVarName+";");
+        unit.emitln("  "+userParamTypeName+"* "+nativeUserParamVarName+";");
+        unit.emitln("  if( NULL != "+cbFuncArgName+" ) {");
+        unit.emitln("    const char* callbackSignature = (*env)->GetStringUTFChars(env, jcallbackSignature, (jboolean*)NULL);");
+        unit.emitln("    if( NULL == callbackSignature ) { (*env)->FatalError(env, \"Failed callbackSignature in '"+jcbFriendlyBasename+"'\"); }");
+        unit.emitln("    jmethodID cbMethodID = (*env)->GetStaticMethodID(env, clazz, \""+staticBindingMethodName+"\", callbackSignature);");
+        unit.emitln("    if( NULL == cbMethodID ) {");
+        unit.emitln("      char cmsg[400];");
+        unit.emitln("      snprintf(cmsg, 400, \"Failed GetStaticMethodID of '"+staticBindingMethodName+"(%s)' in '"+jcbFriendlyBasename+"'\", callbackSignature);");
+        unit.emitln("      (*env)->FatalError(env, cmsg);");
+        unit.emitln("    }");
+        unit.emitln("    (*env)->ReleaseStringUTFChars(env, jcallbackSignature, callbackSignature);");
+        unit.emitln("    "+staticBindingClazzVarName+" = clazz;");
+        unit.emitln("    "+staticBindingMethodIDVarName+" = cbMethodID;");
+        unit.emitln("    "+nativeCBFuncVarName+" = func"+jcbNativeBasename+";");
+        unit.emitln("    "+nativeUserParamVarName+" = ("+userParamTypeName+"*) jnativeUserParam;");
+        unit.emitln("  } else {");
+        unit.emitln("    "+nativeCBFuncVarName+" = NULL;");
+        unit.emitln("    "+nativeUserParamVarName+" = NULL;");
+        unit.emitln("  }");
+        unit.emitln();
+
+    }
+
+    public void emitCAdditionalCode(final CodeUnit unit, final CMethodBindingEmitter jcbCMethodEmitter) {
+        final String jcbNativeBasename = CodeGenUtils.capitalizeString( info.setFuncName );
+        final String jcbFriendlyBasename = info.setFuncName+"("+info.cbSimpleClazzName+")";
+        final String staticBindingClazzVarName = "clazz"+jcbNativeBasename;
+        final String staticBindingMethodIDVarName = "method"+jcbNativeBasename;
+        final String staticCallbackName = "func"+jcbNativeBasename;
+        // final Type userParamType = javaCallback.cbFuncBinding.getCArgumentType(javaCallback.cbFuncUserParamIdx);
+        final String userParamTypeName = info.cbFuncUserParamType.getCName();
+        final String userParamArgName = info.cbFuncBinding.getArgumentName(info.cbFuncUserParamIdx);
+        final Type cReturnType = info.cbFuncBinding.getCReturnType();
+        final JavaType jretType = info.cbFuncBinding.getJavaReturnType();
+        unit.emitln();
+        unit.emitln("static jclass "+staticBindingClazzVarName+" = NULL;");
+        unit.emitln("static jmethodID "+staticBindingMethodIDVarName+" = NULL;");
+        unit.emitln();
+        // javaCallback.cbFuncCEmitter.emitSignature();
+        unit.emit("static "+cReturnType.getCName()+" "+staticCallbackName+"(");
+        // javaCallback.cbFuncCEmitter.emitArguments();
+        unit.emit(info.cbFuncBinding.getCParameterList(new StringBuilder(), false, null).toString());
+        unit.emitln(") {");
+        // javaCallback.cbFuncCEmitter.emitBody();
+        {
+            unit.emitln("  JNIEnv* env = JVMUtil_GetJNIEnv();");
+            unit.emitln("  jclass cbClazz = "+staticBindingClazzVarName+";");
+            unit.emitln("  jmethodID cbMethod = "+staticBindingMethodIDVarName+";");
+            unit.emitln("  if( NULL == env || NULL == cbClazz || NULL == cbMethod ) {");
+            if( !cReturnType.isVoid() ) {
+                unit.emitln("    return 0;");
+            } else {
+                unit.emitln("    return;");
+            }
+            unit.emitln("  }");
+            // javaCallback.cbFuncCEmitter.emitBodyVariableDeclarations();
+            // javaCallback.cbFuncCEmitter.emitBodyUserVariableDeclarations();
+            // javaCallback.cbFuncCEmitter.emitBodyVariablePreCallSetup();
+            emitJavaCallbackBodyCToJavaPreCall(jcbCMethodEmitter);
+
+            // javaCallback.cbFuncCEmitter.emitBodyCallCFunction();
+            unit.emitln("  "+userParamTypeName+"* "+userParamArgName+"_jni = ("+userParamTypeName+"*) "+userParamArgName+";");
+            unit.emitln("  // C Params: "+info.cbFuncBinding.getCParameterList(new StringBuilder(), false, null).toString());
+            unit.emitln("  // J Params: "+info.cbFuncBinding.getJavaParameterList(new StringBuilder()).toString());
+
+            final String returnStatement;
+            if( !cReturnType.isVoid() ) {
+                unit.emit("  "+cReturnType.getCName()+" _res = 0;");
+                returnStatement = "return _res;";
+            } else {
+                returnStatement = "return;";
+            }
+            if( !cReturnType.isVoid() ) {
+                unit.emit("  _res = ("+cReturnType.getCName()+") ");
+            } else {
+                unit.emit("  ");
+            }
+            unit.emit("(*env)->CallStatic" + CodeGenUtils.capitalizeString( jretType.getName() ) +"Method(env, cbClazz, cbMethod, ");
+            // javaCallback.cbFuncCEmitter.emitBodyPassCArguments();
+            emitJavaCallbackBodyPassJavaArguments(unit, jcbCMethodEmitter.binding, null); //"NULL");
+            unit.emitln(");");
+            unit.emitln("  if( (*env)->ExceptionCheck(env) ) {");
+            unit.emitln("    fprintf(stderr, \"Info: Callback '"+jcbFriendlyBasename+"': Exception in Java Callback caught:\\n\");");
+            unit.emitln("    (*env)->ExceptionDescribe(env);");
+            unit.emitln("    (*env)->ExceptionClear(env);");
+            unit.emitln("  }");
+
+            // javaCallback.cbFuncCEmitter.emitBodyUserVariableAssignments();
+            // javaCallback.cbFuncCEmitter.emitBodyVariablePostCallCleanup();
+            // javaCallback.cbFuncCEmitter.emitBodyMapCToJNIType(-1 /* return value */, true /* addLocalVar */)
+
+            unit.emitln("  "+returnStatement);
+        }
+        unit.emitln("}");
+        unit.emitln();
+    }
+
+    /* pp */ int emitJavaCallbackBodyCToJavaPreCall(final CMethodBindingEmitter ce)  {
+        int count = 0;
+        for (int i = 0; i < ce.binding.getNumArguments(); i++) {
+            if( i == info.cbFuncUserParamIdx ) {
+                continue;
+            }
+            if( ce.emitBodyMapCToJNIType(i, true /* addLocalVar */) ) {
+                ++count;
+            }
+        }
+        return count;
+    }
+
+    /* pp */ int emitJavaCallbackBodyPassJavaArguments(final CodeUnit unit, final MethodBinding binding, final String userParamVarName) {
+        int count = 0;
+        boolean needsComma = false;
+        for (int i = 0; i < binding.getNumArguments(); i++) {
+            if (needsComma) {
+                unit.emit(", ");
+                needsComma = false;
+            }
+            if( i == info.cbFuncUserParamIdx && null != userParamVarName ) {
+                unit.emit( userParamVarName );
+            } else {
+                unit.emit( binding.getArgumentName(i) + "_jni" );
+            }
+            needsComma = true;
+            ++count;
+        }
+        return count;
+    }
+
+
+}