Add support for JNI

Makefile

@@ -1,5 +1,5 @@
 SHELL := /bin/bash -euo pipefail
-GOPATH := $(shell pwd)/go:$(JIRI_ROOT)/release/go
+export GOPATH := $(shell pwd)/go:$(JIRI_ROOT)/release/go
 
 .DELETE_ON_ERROR:
 
@@ -30,9 +30,16 @@ c-main-shared: c/main.c c/lib.h build-shared
 	gcc -Wall -o c/main $< c/golib.so
 
 .PHONY: c-main-archive
-c-main-archive: c/main.c c/lib.h build-archive
-	gcc -Wall -o c/main $< c/golib.a
+	gcc -Wall -o c/main $< c/golib.a -lm -lpthread
 
 .PHONY: clean
 clean:
 	rm -rf c/golib* c/main c/lib.h
+
+.PHONY: java
+java: build-shared
+	mkdir -p java/Cgo/src/native/go
+	cp c/golib.h go/src/cgo/lib.h java/Cgo/src/native/go
+	cp c/golib.so java/Cgo/src/native
+	$(MAKE) -C java/Cgo/src/native
+	cd java/Cgo && ./gradlew cleanTest generateJniHeaders build

go/src/cgo/lib.go

@@ -5,6 +5,7 @@ import (
 )
 
 /*
+#cgo LDFLAGS: -lm
 #include <math.h>
 #include "lib.h"
 

go/src/cgo/lib.h

@@ -44,7 +44,7 @@ typedef struct {
 // currying RefMap handles to Swift closures.
 // https://forums.developer.apple.com/message/15725#15725
 
-typedef int x_Handle;
+typedef uint64_t x_Handle;
 
 typedef struct {
   x_Handle h;

java/Cgo/build.gradle

@@ -0,0 +1,27 @@
+version '1.0-SNAPSHOT'
+
+apply plugin: 'java'
+apply plugin: 'c'
+
+repositories {
+    mavenCentral()
+}
+
+task generateJniHeaders(type:Exec) {
+    def classpath = sourceSets.main.output.classesDir
+    commandLine 'javah', '-d', 'src/native/include', '-classpath', classpath, rootProject.name
+
+    dependsOn classes
+}
+
+tasks.withType(Test) {
+    systemProperty 'java.library.path', '/usr/local/google/home/razvanm/github/asadovsky/cgotest/java/Cgo/src/native'
+}
+
+test {
+    environment 'LD_LIBRARY_PATH', '/usr/local/google/home/razvanm/github/asadovsky/cgotest/java/Cgo/src/native'
+}
+
+dependencies {
+    testCompile group: 'junit', name: 'junit', version: '4.11'
+}

java/Cgo/gradle/wrapper/gradle-wrapper.properties

@@ -0,0 +1,6 @@
+#Fri May 06 12:38:56 PDT 2016
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-2.9-bin.zip

java/Cgo/settings.gradle

@@ -0,0 +1,2 @@
+rootProject.name = 'Cgo'
+

java/Cgo/src/main/java/Cgo.java

@@ -0,0 +1,41 @@
+public class Cgo {
+    public static native int add(int a, int b);
+
+    static class AddAndSubResult {
+        int add;
+        int sub;
+    }
+
+    public static native AddAndSubResult addAndSub(int a, int b);
+    public static native void addAndSub(int a, int b, AddAndSubResult result);
+    public static native int div(int a, int b) throws ArithmeticException;
+    public static native int divPtrs(int a, int b) throws ArithmeticException;
+    public static native double sqrt(double x);
+    public static native String echo(String s);
+
+    static class Foo {
+        String str;
+        byte[] arr;
+        int num;
+    }
+    public static native Foo echoFoo(Foo foo) throws Exception;
+
+    interface IntCallback {
+        void onValue(int value);
+    }
+    // Blocking function that will call the handler.onValue for all the values in the stream.
+    public static native void streamInts(int x, IntCallback callback);
+
+    interface IntStreamCallbacks {
+        void onValue(int value);
+        void onDone();
+    }
+    // Non-blocking equivalent of the function from above.
+    public static native void streamInts(int x, IntStreamCallbacks callbacks);
+
+    public static native void addAsync(int a, int b, IntCallback callback);
+
+    static {
+        System.loadLibrary("glue");
+    }
+}