Interop: implement callbacks using libffi

Interop/Indexer/src/main/kotlin/org/jetbrains/kotlin/native/interop/indexer/NativeIndex.kt

@@ -64,38 +64,40 @@ class FunctionDecl(val name: String, val parameters: List<Parameter>, val return
 /**
  * C type.
  */
-open class Type
+interface Type
 
-open class PrimitiveType : Type()
+interface PrimitiveType : Type
 
-object VoidType : Type()
+object VoidType : Type
 
-object Int8Type : PrimitiveType()
-object UInt8Type : PrimitiveType()
+object Int8Type : PrimitiveType
+object UInt8Type : PrimitiveType
 
-object Int16Type : PrimitiveType()
-object UInt16Type : PrimitiveType()
+object Int16Type : PrimitiveType
+object UInt16Type : PrimitiveType
 
-object Int32Type : PrimitiveType()
-object UInt32Type : PrimitiveType()
+object Int32Type : PrimitiveType
+object UInt32Type : PrimitiveType
 
-object IntPtrType : PrimitiveType()
-object UIntPtrType : PrimitiveType()
+object IntPtrType : PrimitiveType
+object UIntPtrType : PrimitiveType
 
-object Int64Type : PrimitiveType()
-object UInt64Type : PrimitiveType()
+object Int64Type : PrimitiveType
+object UInt64Type : PrimitiveType
 
-class RecordType(val decl: StructDecl) : Type()
+data class RecordType(val decl: StructDecl) : Type
 
-class EnumType(val def: EnumDef) : Type()
+data class EnumType(val def: EnumDef) : Type
 
-class PointerType(val pointeeType : Type) : Type()
+data class PointerType(val pointeeType : Type) : Type
 
-class FunctionType(val parameterTypes: List<Type>, val returnType: Type) : Type()
+data class FunctionType(val parameterTypes: List<Type>, val returnType: Type) : Type
 
-open class ArrayType(val elemType: Type) : Type()
-class ConstArrayType(elemType: Type, val length: Long) : ArrayType(elemType)
-class IncompleteArrayType(elemType: Type) : ArrayType(elemType)
+interface ArrayType : Type {
+    val elemType: Type
+}
 
-object UnsupportedType : Type()
+data class ConstArrayType(override val elemType: Type, val length: Long) : ArrayType
+data class IncompleteArrayType(override val elemType: Type) : ArrayType
 
+object UnsupportedType : Type

Interop/Runtime/build.gradle

@@ -9,6 +9,27 @@ buildscript {
 }
 
 apply plugin: 'kotlin'
+apply plugin: 'c'
+
+def javaHome = System.getProperty('java.home')
+def compilerArgsForJniIncludes = ["", "linux", "darwin"].collect { "-I$javaHome/../include/$it" } as String[]
+
+model {
+    components {
+        callbacks(NativeLibrarySpec) {
+            sources.c.source {
+                srcDir 'src/callbacks/c'
+                include '**/*.c'
+            }
+            binaries.all {
+                cCompiler.args compilerArgsForJniIncludes
+                cCompiler.args "-I$ffiIncludePath"
+                linker.args "$ffiLibPath/libffi.a"
+            }
+        }
+   }
+
+}
 
 repositories {
     mavenCentral()
@@ -17,3 +38,13 @@ repositories {
 dependencies {
     compile "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
 }
+
+
+task nativelibs(type: Copy) {
+    dependsOn 'callbacksSharedLibrary'
+
+    from "$buildDir/libs/callbacks/shared/"
+    into "$buildDir/nativelibs/"
+}
+
+classes.dependsOn nativelibs

Interop/Runtime/src/callbacks/c/callbacks.c

@@ -0,0 +1,233 @@
+#include <stdlib.h>
+#include <assert.h>
+#include <jni.h>
+#include <ffi.h>
+
+/*
+ * Class:     kotlin_native_interop_CallbacksKt
+ * Method:    ffiTypeVoid
+ * Signature: ()J
+ */
+JNIEXPORT jlong JNICALL Java_kotlin_1native_interop_CallbacksKt_ffiTypeVoid(JNIEnv *env, jclass cls) {
+    return (jlong) &ffi_type_void;
+}
+
+/*
+ * Class:     kotlin_native_interop_CallbacksKt
+ * Method:    ffiTypeUInt8
+ * Signature: ()J
+ */
+JNIEXPORT jlong JNICALL Java_kotlin_1native_interop_CallbacksKt_ffiTypeUInt8(JNIEnv *env, jclass cls) {
+    return (jlong) &ffi_type_uint8;
+}
+
+/*
+ * Class:     kotlin_native_interop_CallbacksKt
+ * Method:    ffiTypeSInt8
+ * Signature: ()J
+ */
+JNIEXPORT jlong JNICALL Java_kotlin_1native_interop_CallbacksKt_ffiTypeSInt8(JNIEnv *env, jclass cls) {
+    return (jlong) &ffi_type_sint8;
+}
+
+/*
+ * Class:     kotlin_native_interop_CallbacksKt
+ * Method:    ffiTypeUInt16
+ * Signature: ()J
+ */
+JNIEXPORT jlong JNICALL Java_kotlin_1native_interop_CallbacksKt_ffiTypeUInt16(JNIEnv *env, jclass cls) {
+    return (jlong) &ffi_type_uint16;
+}
+
+/*
+ * Class:     kotlin_native_interop_CallbacksKt
+ * Method:    ffiTypeSInt16
+ * Signature: ()J
+ */
+JNIEXPORT jlong JNICALL Java_kotlin_1native_interop_CallbacksKt_ffiTypeSInt16(JNIEnv *env, jclass cls) {
+    return (jlong) &ffi_type_sint16;
+}
+
+/*
+ * Class:     kotlin_native_interop_CallbacksKt
+ * Method:    ffiTypeUInt32
+ * Signature: ()J
+ */
+JNIEXPORT jlong JNICALL Java_kotlin_1native_interop_CallbacksKt_ffiTypeUInt32(JNIEnv *env, jclass cls) {
+    return (jlong) &ffi_type_uint32;
+}
+
+/*
+ * Class:     kotlin_native_interop_CallbacksKt
+ * Method:    ffiTypeSInt32
+ * Signature: ()J
+ */
+JNIEXPORT jlong JNICALL Java_kotlin_1native_interop_CallbacksKt_ffiTypeSInt32(JNIEnv *env, jclass cls) {
+    return (jlong) &ffi_type_sint32;
+}
+
+/*
+ * Class:     kotlin_native_interop_CallbacksKt
+ * Method:    ffiTypeUInt64
+ * Signature: ()J
+ */
+JNIEXPORT jlong JNICALL Java_kotlin_1native_interop_CallbacksKt_ffiTypeUInt64(JNIEnv *env, jclass cls) {
+    return (jlong) &ffi_type_uint64;
+}
+
+/*
+ * Class:     kotlin_native_interop_CallbacksKt
+ * Method:    ffiTypeSInt64
+ * Signature: ()J
+ */
+JNIEXPORT jlong JNICALL Java_kotlin_1native_interop_CallbacksKt_ffiTypeSInt64(JNIEnv *env, jclass cls) {
+    return (jlong) &ffi_type_sint64;
+}
+
+/*
+ * Class:     kotlin_native_interop_CallbacksKt
+ * Method:    ffiTypePointer
+ * Signature: ()J
+ */
+JNIEXPORT jlong JNICALL Java_kotlin_1native_interop_CallbacksKt_ffiTypePointer(JNIEnv *env, jclass cls) {
+    return (jlong) &ffi_type_pointer;
+}
+
+/*
+ * Class:     kotlin_native_interop_CallbacksKt
+ * Method:    ffiTypeStruct0
+ * Signature: (J)J
+ */
+JNIEXPORT jlong JNICALL Java_kotlin_1native_interop_CallbacksKt_ffiTypeStruct0(JNIEnv *env, jclass cls, jlong elements) {
+    ffi_type* res = malloc(sizeof(ffi_type));
+    if (res != NULL) {
+        res->elements = (ffi_type**) elements;
+        res->type = FFI_TYPE_STRUCT;
+    }
+    return (jlong) res;
+}
+
+/*
+ * Class:     kotlin_native_interop_CallbacksKt
+ * Method:    ffiCreateCif0
+ * Signature: (IJJ)J
+ */
+JNIEXPORT jlong JNICALL Java_kotlin_1native_interop_CallbacksKt_ffiCreateCif0(JNIEnv *env, jclass cls, jint nArgs, jlong rType, jlong argTypes) {
+    ffi_cif* res = malloc(sizeof(ffi_cif));
+    if (res != NULL) {
+        ffi_status status = ffi_prep_cif(res, FFI_DEFAULT_ABI, nArgs, (ffi_type*)rType, (ffi_type**)argTypes);
+        if (status != FFI_OK) {
+            if (status == FFI_BAD_TYPEDEF) {
+                return -(jlong)1;
+            } else if (status == FFI_BAD_ABI) {
+                return -(jlong)2;
+            } else {
+                return -(jlong)3;
+            }
+        }
+    }
+    return (jlong) res;
+}
+
+static JavaVM *vm = NULL;
+
+// Returns the JNI env which can be used by the caller.
+// If current thread is not attached to JVM, then it gets attached as daemon.
+static JNIEnv* getCurrentEnv() {
+    JNIEnv* env;
+    assert(vm != NULL);
+    jint res = (*vm)->GetEnv(vm, (void**)&env, JNI_VERSION_1_1);
+    if (res != JNI_OK) {
+        assert(res == JNI_EDETACHED);
+        res = (*vm)->AttachCurrentThreadAsDaemon(vm, (void**)&env, NULL);
+        assert(res == JNI_OK);
+    }
+    return env;
+}
+
+jint JNI_OnLoad(JavaVM *vm_, void *reserved) {
+    vm = vm_;
+    return JNI_VERSION_1_1;
+}
+
+// Checks for pending exception. If there is one, describes it and terminates the process.
+static void checkException(JNIEnv *env) {
+    if ((*env)->ExceptionCheck(env)) {
+        (*env)->ExceptionDescribe(env);
+        abort();
+    }
+}
+
+static void ffi_fun(ffi_cif *cif, void *ret, void **args, void *user_data) {
+    JNIEnv* env = getCurrentEnv();
+
+    static jmethodID ffiFunImpl0 = NULL;
+    static jclass cls = NULL;
+    if (ffiFunImpl0 == NULL) {
+        cls = (*env)->FindClass(env, "kotlin_native/interop/CallbacksKt");
+        checkException(env);
+        assert(cls != NULL);
+
+        ffiFunImpl0 = (*env)->GetStaticMethodID(env, cls, "ffiFunImpl0", "(JJJLjava/lang/Object;)V");
+        checkException(env);
+        assert(ffiFunImpl0 != NULL);
+    }
+
+    (*env)->CallStaticVoidMethod(env, cls, ffiFunImpl0, (jlong) cif, (jlong) ret, (jlong) args, (jobject) user_data);
+    checkException(env);
+}
+
+/*
+ * Class:     kotlin_native_interop_CallbacksKt
+ * Method:    ffiCreateClosure0
+ * Signature: (JLjava/lang/Object;)J
+ */
+JNIEXPORT jlong JNICALL Java_kotlin_1native_interop_CallbacksKt_ffiCreateClosure0(JNIEnv *env, jclass cls, jlong ffiCif, jobject userData) {
+    jobject userDataGlobalRef = (*env)->NewGlobalRef(env, userData);
+    if (userDataGlobalRef == NULL) {
+        return (jlong)0;
+    }
+
+    assert(sizeof(jobject) == sizeof(void*)); // TODO: check statically
+    void* userDataPtr = (void*) userDataGlobalRef;
+
+    void* res;
+    ffi_closure *closure = ffi_closure_alloc(sizeof(ffi_closure), &res);
+    if (closure == NULL) {
+        return (jlong)0;
+    }
+    ffi_status status = ffi_prep_closure_loc(closure, (ffi_cif*)ffiCif, ffi_fun, userDataPtr, res);
+    if (status != FFI_OK) {
+        return -(jlong)1;
+    }
+
+    return (jlong) res;
+}
+
+/*
+ * Class:     kotlin_native_interop_CallbacksKt
+ * Method:    newGlobalRef
+ * Signature: (Ljava/lang/Object;)J
+ */
+JNIEXPORT jlong JNICALL Java_kotlin_1native_interop_CallbacksKt_newGlobalRef(JNIEnv *env, jclass cls, jobject obj) {
+    jobject res = (*env)->NewGlobalRef(env, obj);
+    return (jlong) res;
+}
+
+/*
+ * Class:     kotlin_native_interop_CallbacksKt
+ * Method:    derefGlobalRef
+ * Signature: (J)Ljava/lang/Object;
+ */
+JNIEXPORT jobject JNICALL Java_kotlin_1native_interop_CallbacksKt_derefGlobalRef(JNIEnv *env, jclass cls, jlong ref) {
+    return (jobject) ref;
+}
+
+/*
+ * Class:     kotlin_native_interop_CallbacksKt
+ * Method:    deleteGlobalRef
+ * Signature: (J)V
+ */
+JNIEXPORT void JNICALL Java_kotlin_1native_interop_CallbacksKt_deleteGlobalRef(JNIEnv *env, jclass cls, jlong ref) {
+    (*env)->DeleteGlobalRef(env, (jobject) ref);
+}

Interop/Runtime/src/main/kotlin/kotlin_native/interop/Callbacks.kt

@@ -0,0 +1,287 @@
+package kotlin_native.interop
+
+/**
+ * This class provides a way to create a stable handle to any Kotlin object.
+ * Its [value] can be safely passed to native code e.g. to be received in a Kotlin callback.
+ *
+ * Any [StableObjPtr] should be manually [disposed][dispose]
+ */
+data class StableObjPtr private constructor(val value: NativePtr) {
+
+    companion object {
+
+        /**
+         * Creates a handle for given object.
+         */
+        fun create(any: Any) = StableObjPtr(NativePtr.byValue(newGlobalRef(any))!!)
+
+        /**
+         * Creates [StableObjPtr] from given raw value.
+         *
+         * @param value must be a [value] of some [StableObjPtr]
+         */
+        fun fromValue(value: NativePtr) = StableObjPtr(value)
+
+        init {
+            loadCallbacksLibrary()
+        }
+    }
+
+    /**
+     * Disposes the handle. It must not be [used][get] after that.
+     */
+    fun dispose() {
+        deleteGlobalRef(value.value)
+    }
+
+    /**
+     * Returns the object this handle was [created][create] for.
+     */
+    fun get(): Any = derefGlobalRef(value.value)
+
+}
+
+/**
+ * Describes the type of native function.
+ *
+ * The instances of this class are supposed to be Kotlin objects (singletons),
+ * because creating the instance implies allocating some amount of non-freeable memory for the instance itself
+ * and for any unique Kotlin function "converted" to this type.
+ *
+ * Native function type definition consists in the following:
+ * -   Definitions of native function's parameter and return types to be passed into the constructor
+ * -   Implementation of [invoke] method which describes how to convert between these types and Kotlin types used in [F]
+ *
+ * @param F Kotlin function type corresponding to given native function type
+*/
+abstract class NativeFunctionType<F : Function<*>> protected constructor(returnType: CType, vararg paramTypes: CType) {
+
+    /**
+     * Returns a native function of this type, which calls given Kotlin *static* function.
+     *
+     * Given function must be *static*, i.e. an (unbound) reference to a Kotlin function or
+     * a closure which doesn't capture any variable
+     */
+    fun fromStatic(function: F): NativePtr {
+        // TODO: optimize synchronization
+        synchronized(cache) {
+            return cache.getOrPut(function, { createFromStatic(function) })
+        }
+    }
+
+    /**
+     * Describes the C type of a function's parameter or return value.
+     * It is supposed to be constructed using the primitive types (such as [SInt32]) and the [Struct] combinator.
+     *
+     * This description omits the details that are irrelevant for the ABI.
+     */
+    protected open class CType internal constructor(val ffiType: ffi_type) {
+        internal constructor(ffiTypePtr: Long) : this(NativePtr.byValue(ffiTypePtr).asRef(ffi_type)!!)
+    }
+
+    protected object Void    : CType(ffiTypeVoid())
+    protected object UInt8   : CType(ffiTypeUInt8())
+    protected object SInt8   : CType(ffiTypeSInt8())
+    protected object UInt16  : CType(ffiTypeUInt16())
+    protected object SInt16  : CType(ffiTypeSInt16())
+    protected object UInt32  : CType(ffiTypeUInt32())
+    protected object SInt32  : CType(ffiTypeSInt32())
+    protected object UInt64  : CType(ffiTypeUInt64())
+    protected object SInt64  : CType(ffiTypeSInt64())
+    protected object Pointer : CType(ffiTypePointer())
+
+    protected class Struct(vararg elementTypes: CType) : CType(
+            ffiTypeStruct(
+                    elementTypes.map { it.ffiType }
+            )
+    )
+
+    /**
+     * This method should invoke given Kotlin function.
+     *
+     * @param args array of pointers to arguments to be passed to [function]
+     * @param ret pointer to memory to be filled with return value of [function]
+     */
+    protected abstract fun invoke(function: F, args: NativeArray<NativePtrBox>, ret: NativePtr)
+
+    companion object {
+        init {
+            loadCallbacksLibrary()
+        }
+    }
+
+    private val ffiCif = ffiCreateCif(returnType.ffiType, paramTypes.map { it.ffiType })
+
+    /**
+     * Allocates a native function of this type for given Kotlin function.
+     */
+    private fun createFromStatic(function: F): NativePtr {
+        if (!isStatic(function)) {
+            throw IllegalArgumentException()
+        }
+
+        val impl = { ret: NativePtr, args: NativeArray<NativePtrBox> ->
+            invoke(function, args, ret)
+        }
+
+        return ffiCreateClosure(ffiCif, impl)
+    }
+
+    /**
+     * Returns `true` if given function is *static* as defined in [fromStatic].
+     */
+    private fun isStatic(function: Function<*>): Boolean {
+        // TODO: revise
+        try {
+            with(function.javaClass.getDeclaredField("INSTANCE")) {
+                if (!java.lang.reflect.Modifier.isStatic(modifiers) || !java.lang.reflect.Modifier.isFinal(modifiers)) {
+                    return false
+                }
+
+                isAccessible = true // TODO: undo
+
+                return get(null) == function
+            }
+        } catch (e: NoSuchFieldException) {
+            return false
+        }
+    }
+
+    private val cache = mutableMapOf<F, NativePtr>()
+}
+
+/**
+ * @see NativeFunctionType.fromStatic
+ */
+fun <F : Function<*>> F.staticAsNative(type: NativeFunctionType<F>) = type.fromStatic(this)
+
+/**
+ * Describes a "struct" with native function pointer field.
+ */
+class NativeFunctionBox<F : Function<*>>(ptr: NativePtr, private val type: NativeFunctionType<F>) : NativeRef(ptr) {
+
+    /**
+     * Sets the function pointer field to null or native function calling given Kotlin function.
+     */
+    fun setStatic(function: F?) {
+        val nativeFunPtr = function?.staticAsNative(type)
+        bridge.putPtr(ptr, nativeFunPtr)
+    }
+}
+
+val <F : Function<*>> NativeFunctionType<F>.ref: NativeRef.TypeWithSize<NativeFunctionBox<F>>
+    get() = NativeRef.TypeWithSize(8, { NativeFunctionBox(it, this) }) // TODO: 64-bit specific
+
+
+private fun loadCallbacksLibrary() {
+    System.loadLibrary("callbacks")
+}
+
+
+/**
+ * Reference to `ffi_type` struct instance.
+ */
+internal class ffi_type (ptr: NativePtr) : NativeRef(ptr) {
+    companion object : Type<ffi_type>(::ffi_type)
+}
+
+/**
+ * Reference to `ffi_cif` struct instance.
+ */
+internal class ffi_cif (ptr: NativePtr) : NativeRef(ptr) {
+    companion object : Type<ffi_cif>(::ffi_cif)
+}
+
+private external fun ffiTypeVoid(): Long
+private external fun ffiTypeUInt8(): Long
+private external fun ffiTypeSInt8(): Long
+private external fun ffiTypeUInt16(): Long
+private external fun ffiTypeSInt16(): Long
+private external fun ffiTypeUInt32(): Long
+private external fun ffiTypeSInt32(): Long
+private external fun ffiTypeUInt64(): Long
+private external fun ffiTypeSInt64(): Long
+private external fun ffiTypePointer(): Long
+
+private external fun ffiTypeStruct0(elements: Long): Long
+
+/**
+ * Allocates and initializes `ffi_type` describing the struct.
+ *
+ * @param elements types of the struct elements
+ */
+private fun ffiTypeStruct(elementTypes: List<ffi_type>): ffi_type {
+    val elements = mallocNativeArrayOf(ffi_type, *elementTypes.toTypedArray(), null).ptr
+    val res = ffiTypeStruct0(elements.value)
+    if (res == 0L) {
+        throw OutOfMemoryError()
+    }
+    return NativePtr.byValue(res).asRef(ffi_type)!!
+}
+
+private external fun ffiCreateCif0(nArgs: Int, rType: Long, argTypes: Long): Long
+
+/**
+ * Creates and prepares an `ffi_cif`.
+ *
+ * @param returnType native function return value type
+ * @param paramTypes native function parameter types
+ *
+ * @return the initialized `ffi_cif`
+ */
+private fun ffiCreateCif(returnType: ffi_type, paramTypes: List<ffi_type>): ffi_cif {
+    val nArgs = paramTypes.size
+    val rType = returnType.ptr
+    val argTypes = mallocNativeArrayOf(ffi_type, *paramTypes.toTypedArray(), null).ptr
+    val res = ffiCreateCif0(nArgs, rType.value, argTypes.value)
+
+    when (res) {
+        0L -> throw OutOfMemoryError()
+        -1L -> throw Error("FFI_BAD_TYPEDEF")
+        -2L -> throw Error("FFI_BAD_ABI")
+        -3L -> throw Error("libffi error occurred")
+    }
+
+    return NativePtr.byValue(res).asRef(ffi_cif)!!
+}
+
+private fun ffiFunImpl0(ffiCif: Long, ret: Long, args: Long, userData: Any) {
+    ffiFunImpl(NativePtr.byValue(ffiCif).asRef(ffi_cif)!!,
+            NativePtr.byValue(ret)!!,
+            NativePtr.byValue(args).asRef(array(NativePtrBox))!!,
+            userData as (ret: NativePtr, args: NativeArray<NativePtrBox>) -> Unit)
+}
+
+/**
+ * This function is called from native code when a native function created with [ffiCreateClosure] is invoked.
+ *
+ * @param ret pointer to memory to be filled with return value of the invoked native function
+ * @param args pointer to array of pointers to arguments passed to the invoked native function
+ */
+private fun ffiFunImpl(ffiCif: ffi_cif, ret: NativePtr, args: NativeArray<NativePtrBox>,
+                       userData: (NativePtr, NativeArray<NativePtrBox>) -> Unit) {
+
+    userData.invoke(ret, args)
+}
+
+private external fun ffiCreateClosure0(ffiCif: Long, userData: Any): Long
+
+/**
+ * Uses libffi to allocate a native function which will call [ffiFunImpl] when invoked.
+ *
+ * @param ffiCif describes the type of the function to create
+ */
+private fun ffiCreateClosure(ffiCif: ffi_cif, userData: (NativePtr, NativeArray<NativePtrBox>) -> Unit): NativePtr {
+    val res = ffiCreateClosure0(ffiCif.ptr.value, userData)
+
+    when (res) {
+        0L -> throw OutOfMemoryError()
+        -1L -> throw Error("libffi error occurred")
+    }
+
+    return NativePtr.byValue(res)!!
+}
+
+private external fun newGlobalRef(any: Any): Long
+private external fun derefGlobalRef(ref: Long): Any
+private external fun deleteGlobalRef(ref: Long)

Interop/StubGenerator/src/main/kotlin/org/jetbrains/kotlin/native/interop/gen/jvm/StubGenerator.kt

@@ -66,6 +66,15 @@ class StubGenerator(
 
     val functionsToBind = nativeIndex.functions.filter { it.name !in excludedFunctions }
 
+    private val usedFunctionTypes = mutableMapOf<FunctionType, String>()
+
+    val FunctionType.kotlinName: String
+        get() {
+            return usedFunctionTypes.getOrPut(this, {
+                "NativeFunctionType" + (usedFunctionTypes.size + 1)
+            })
+        }
+
     /**
      * The output currently used by the generator.
      * Should append line separator after any usage.
@@ -181,10 +190,13 @@ class StubGenerator(
         }
 
         is PointerType -> {
-            if (type.pointeeType is VoidType || type.pointeeType is FunctionType) {
+            val pointeeType = type.pointeeType
+            if (pointeeType is VoidType) {
                 NativeRefType("NativePtrBox")
+            } else if (pointeeType is FunctionType) {
+                NativeRefType("NativeFunctionBox<${getKotlinFunctionType(pointeeType)}>", "${pointeeType.kotlinName}.ref")
             } else {
-                val pointeeRefType = getKotlinTypeForRefTo(type.pointeeType)
+                val pointeeRefType = getKotlinTypeForRefTo(pointeeType)
                 NativeRefType("RefBox<${pointeeRefType.typeName}>", "${pointeeRefType.typeExpr}.ref")
             }
         }
@@ -258,13 +270,6 @@ class StubGenerator(
                         kotlinConv = { "$it.asLong()" },
                         kotlinJniBridgeType = "Long"
                 )
-            } else if (type.pointeeType is Int8Type) {
-                OutValueBinding(
-                        kotlinType = "String?",
-                        kotlinConv = { name -> "CString.fromString($name).getNativePtr().asLong()" },
-                        convFree = { name -> "free(NativePtr.byValue($name))" },
-                        kotlinJniBridgeType = "Long"
-                )
             } else {
                 outValueRefBinding(getKotlinTypeForRefTo(type.pointeeType))
             }
@@ -282,17 +287,51 @@ class StubGenerator(
 
         is ArrayType -> outValueRefBinding(getKotlinTypeForRefTo(type))
 
-        is RecordType -> {
-            val refType = getKotlinTypeForRefTo(type)
-            // pointer will be converted to value in C code
-            OutValueBinding(
-                    kotlinType = refType.typeName,
-                    kotlinConv = { "$it.getNativePtr().asLong()" },
-                    kotlinJniBridgeType = "Long"
+        else -> throw NotImplementedError()
+    }
+
+    fun getCFunctionParamBinding(type: Type): OutValueBinding {
+        when (type) {
+            is PointerType -> {
+                val pointeeType = type.pointeeType
+                when (pointeeType) {
+                    is FunctionType -> return OutValueBinding(
+                            kotlinType = "(" + getKotlinFunctionType(pointeeType) + ")?",
+                            kotlinConv = { "$it?.staticAsNative(${pointeeType.kotlinName}).asLong()" },
+                            kotlinJniBridgeType = "Long"
+                    )
+                    is Int8Type -> return OutValueBinding(
+                            kotlinType = "String?",
+                            kotlinConv = { name -> "CString.fromString($name).getNativePtr().asLong()" },
+                            convFree = { name -> "free(NativePtr.byValue($name))" },
+                            kotlinJniBridgeType = "Long"
+                    )
+                }
+            }
+            is RecordType -> {
+                val refType = getKotlinTypeForRefTo(type)
+                // pointer will be converted to value in C code
+                return OutValueBinding(
+                        kotlinType = refType.typeName,
+                        kotlinConv = { "$it.getNativePtr().asLong()" },
+                        kotlinJniBridgeType = "Long"
+                )
+            }
+        }
+
+        return getOutValueBinding(type)
+    }
+
+    fun getCallbackRetValBinding(type: Type): OutValueBinding {
+        if (type is VoidType) {
+            return OutValueBinding(
+                    kotlinType = "Unit",
+                    kotlinConv = { throw UnsupportedOperationException() },
+                    kotlinJniBridgeType = "void"
             )
         }
 
-        else -> throw NotImplementedError()
+        return getOutValueBinding(type)
     }
 
     /**
@@ -302,8 +341,6 @@ class StubGenerator(
 
         is PrimitiveType -> InValueBinding(type.kotlinType)
 
-        is VoidType -> InValueBinding("Unit")
-
         is PointerType -> {
             if (type.pointeeType is VoidType || type.pointeeType is FunctionType) {
                 InValueBinding(
@@ -328,17 +365,35 @@ class StubGenerator(
 
         is ArrayType -> inValueRefBinding(getKotlinTypeForRefTo(type))
 
-        is RecordType -> {
-            // TODO: valid only for return values
-            val refType = getKotlinTypeForRefTo(type)
-            InValueBinding(
-                    kotlinJniBridgeType = "Long",
-                    conv = { "NativePtr.byValue($it).asRef(${refType.typeExpr})!!" },
-                    kotlinType = refType.typeName
-            )
+        else -> throw NotImplementedError()
+    }
+
+    fun getCFunctionRetValBinding(type: Type): InValueBinding {
+        when (type) {
+            is VoidType -> return InValueBinding("Unit")
+
+            is RecordType -> {
+                val refType = getKotlinTypeForRefTo(type)
+                InValueBinding(
+                        kotlinJniBridgeType = "Long",
+                        conv = { "NativePtr.byValue($it).asRef(${refType.typeExpr})!!" },
+                        kotlinType = refType.typeName
+                )
+            }
         }
 
-        else -> throw NotImplementedError()
+        return getInValueBinding(type)
+    }
+
+    fun getCallbackParamBinding(type: Type): InValueBinding {
+        return getInValueBinding(type)
+    }
+
+    private fun getKotlinFunctionType(type: FunctionType): String {
+        return "(" +
+                type.parameterTypes.map { getCallbackParamBinding(it).kotlinType }.joinToString(", ") +
+                ") -> " +
+                getCallbackRetValBinding(type.returnType).kotlinType
     }
 
     /**
@@ -437,14 +492,14 @@ class StubGenerator(
     /**
      * Constructs [InValueBinding] for return value of Kotlin binding for given C function.
      */
-    private fun retValBinding(func: FunctionDecl) = getInValueBinding(func.returnType)
+    private fun retValBinding(func: FunctionDecl) = getCFunctionRetValBinding(func.returnType)
 
     /**
      * Constructs [OutValueBinding]s for parameters of Kotlin binding for given C function.
      */
     private fun paramBindings(func: FunctionDecl): Array<OutValueBinding> {
         val paramBindings = func.parameters.map { param ->
-            getOutValueBinding(param.type)
+            getCFunctionParamBinding(param.type)
         }.toMutableList()
 
         val retValType = func.returnType
@@ -523,6 +578,63 @@ class StubGenerator(
         out("}")
     }
 
+    private fun getFfiType(type: Type): String {
+        return when(type) {
+            is VoidType -> "Void"
+            is Int8Type -> "SInt8"
+            is UInt8Type -> "UInt8"
+            is Int16Type -> "SInt16"
+            is UInt16Type -> "UInt16"
+            is Int32Type -> "SInt32"
+            is UInt32Type -> "UInt32"
+            is IntPtrType, is UIntPtrType, // TODO
+            is PointerType, is ArrayType -> "Pointer"
+            is EnumType -> getFfiType(type.def.baseType)
+            // FIXME: check that alignment is natural
+            is RecordType -> "Struct(" + type.decl.def!!.fields.map {
+                getFfiType(it.type)
+            }.joinToString(", ") + ")"
+            else -> throw NotImplementedError(type.toString())
+        }
+    }
+
+    private fun generateFunctionType(type: FunctionType, name: String) {
+        val kotlinFunctionType = getKotlinFunctionType(type)
+
+        val constructorArgs = listOf(type.returnType, *type.parameterTypes.toTypedArray()).map {
+            getFfiType(it)
+        }.joinToString(", ")
+
+        out("object $name : NativeFunctionType<$kotlinFunctionType>($constructorArgs) {")
+        indent {
+            out("override fun invoke(function: $kotlinFunctionType, args: NativeArray<NativePtrBox>, ret: NativePtr) {")
+            indent {
+                val args = type.parameterTypes.mapIndexed { i, paramType ->
+                    val refType = getKotlinTypeForRefTo(paramType)
+                    val ref = "args[$i].value.asRef(${refType.typeExpr})!!"
+                    when (paramType) {
+                        is RecordType -> "$ref"
+                        else -> "$ref.value"
+                    }
+                }.joinToString(", ")
+
+                out("val res = function($args)")
+
+                when (type.returnType) {
+                    is RecordType -> throw NotImplementedError()
+                    is VoidType -> {} // nothing to do
+                    else -> {
+                        val retRefType = getKotlinTypeForRefTo(type.returnType)
+                        out("${retRefType.typeExpr}.byPtr(ret).value = res")
+                    }
+                }
+
+            }
+            out("}")
+        }
+        out("}")
+    }
+
     /**
      * Produces to [out] the definition of Kotlin JNI function used in binding for given C function.
      */
@@ -576,6 +688,11 @@ class StubGenerator(
             out("")
         }
 
+        usedFunctionTypes.entries.forEach {
+            generateFunctionType(it.key, it.value)
+            out("")
+        }
+
         out("object externals {")
         indent {
             out("init { System.loadLibrary(\"$libName\") }")

buildSrc/src/main/groovy/org/jetbrains/kotlin/NativeInteropPlugin.groovy

@@ -8,6 +8,8 @@ class NativeInteropPlugin implements Plugin<Project> {
 
     @Override
     void apply(Project prj) {
+        def runtimeNativeLibsDir = new File(prj.findProject(':Interop:Runtime').buildDir, 'nativelibs')
+
         def nativeLibsDir = new File(prj.buildDir, "nativelibs")
 
         prj.configurations {
@@ -30,7 +32,11 @@ class NativeInteropPlugin implements Plugin<Project> {
                 main = "org.jetbrains.kotlin.native.interop.gen.jvm.MainKt"
                 jvmArgs '-ea'
 
-                systemProperties "java.library.path" : new File(prj.findProject(":Interop:Indexer").buildDir, "nativelibs")
+
+                systemProperties "java.library.path" : prj.files(
+                        new File(prj.findProject(":Interop:Indexer").buildDir, "nativelibs"),
+                        runtimeNativeLibsDir
+                ).asPath
                 systemProperties "llvmInstallPath" : prj.llvmInstallPath
                 environment "LIBCLANG_DISABLE_CRASH_RECOVERY": "1"
                 environment "DYLD_LIBRARY_PATH": "${prj.llvmInstallPath}/lib"
@@ -60,7 +66,10 @@ class NativeInteropPlugin implements Plugin<Project> {
         // FIXME: choose tasks more wisely
         prj.tasks.withType(JavaExec) {
             if (!name.endsWith("InteropStubs")) {
-                systemProperties "java.library.path": nativeLibsDir
+                systemProperties "java.library.path": prj.files(
+                        nativeLibsDir,
+                        runtimeNativeLibsDir
+                ).asPath
             }
         }
     }