ble/jni_android.go

package ble

/*
#cgo LDFLAGS: -landroid -llog

#import "jni_android.h"
*/
import "C"

import (
	"errors"
	"fmt"
	"log"
	"runtime"
	"unsafe"
)

var theJVM *C.JavaVM

type JNIEnv = C.JNIEnv

func setJVM(jvm uintptr) {
	log.Printf("set theJVM")
	theJVM = (*C.JavaVM)(unsafe.Pointer(jvm))
	if theJVM == nil {
		log.Printf("theJVM is nil!")
	} else {
		log.Printf("theJVM is not nil")
	}
}

func runInJVM(f func(env *C.JNIEnv)) {
	runtime.LockOSThread()
	defer runtime.UnlockOSThread()
	var env *C.JNIEnv
	var detach bool
	//log.Printf("RunInJVM(): theJVM = %d", uintptr(unsafe.Pointer(theJVM)))
	if res := C.GetEnv(theJVM, &env, C.JNI_VERSION_1_6); res != C.JNI_OK {
		if res != C.JNI_EDETACHED {
			panic(fmt.Errorf("JNI GetEnv failed with error %d", res))
		}
		if C.AttachCurrentThread(theJVM, &env, nil) != C.JNI_OK {
			panic(errors.New("runInJVM: AttachCurrentThread failed"))
		}
		detach = true
	}

	if detach {
		defer func() {
			C.DetachCurrentThread(theJVM)
		}()
	}
	f(env)
}