/*

* Copyright (C) 2013 Klaus Reimer (k@ailis.de)

* Copyright (C) 2013 Luca Longinotti (l@longi.li)

* See LICENSE.md file for copying conditions

*/

#include "usb4java.h"

#include <stdarg.h>

#include <stdio.h>

JavaVM *jvm = NULL;

jclass jClassLibUsb = NULL;

jmethodID jMethodTriggerPollfdAdded = NULL;

jmethodID jMethodTriggerPollfdRemoved = NULL;

jmethodID jMethodHotplugCallback = NULL;

jint illegalArgument(JNIEnv *env, const char *message, ...)

{

char tmp[256];

va_list args;

va_start(args, message);

vsnprintf(tmp, 256, message, args);

va_end(args);

return (*env)->ThrowNew(env, (*env)->FindClass(env,

"java/lang/IllegalArgumentException"), tmp);

}

jint illegalState(JNIEnv *env, const char *message, ...)

{

char tmp[256];

va_list args;

va_start(args, message);

vsnprintf(tmp, 256, message, args);

va_end(args);

return (*env)->ThrowNew(env, (*env)->FindClass(env,

"java/lang/IllegalStateException"), tmp);

}

jobject NewDirectReadOnlyByteBuffer(JNIEnv *env, const void *mem,

int mem_length)

{

jobject buffer = (*env)->NewDirectByteBuffer(env, (void *) mem, mem_length);

// Get a read-only buffer from this buffer.

jclass cls = (*env)->GetObjectClass(env, buffer);

jmethodID method = (*env)->GetMethodID(env, cls, "asReadOnlyBuffer",

"()Ljava/nio/ByteBuffer;");

return (*env)->CallObjectMethod(env, buffer, method);

}

jint JNICALL JNI_OnLoad(JavaVM *vm, void *reserved)

{

JNIEnv *env;

jint getEnvResult;

// Set JVM to the current one.

jvm = vm;

// Get the current environment.

getEnvResult = (*vm)->GetEnv(vm, (void **) &env, JNI_VERSION_1_6);

if (getEnvResult != JNI_OK)

{

// Send unrecognized version to signal error and deny library load.

return -1;

}

// Find classes and methods and cache them.

// Persistence is guaranteed by global references.

jClassLibUsb = (*env)->FindClass(env, CLASS_PATH("LibUsb"));

jClassLibUsb = (*env)->NewGlobalRef(env, jClassLibUsb);

jMethodTriggerPollfdAdded = (*env)->GetStaticMethodID(env, jClassLibUsb,

"triggerPollfdAdded", "(Ljava/io/FileDescriptor;IJ)V");

jMethodTriggerPollfdRemoved = (*env)->GetStaticMethodID(env, jClassLibUsb,

"triggerPollfdRemoved", "(Ljava/io/FileDescriptor;J)V");

jMethodHotplugCallback = (*env)->GetStaticMethodID(env, jClassLibUsb,

"hotplugCallback", "(L"CLASS_PATH("Context;L")CLASS_PATH("Device;IJ)I"));

return JNI_VERSION_1_6;

}

void JNICALL JNI_OnUnload(JavaVM *vm, void *reserved)

{

// Get the current environment.

JNIEnv *env;

jint getEnvResult = (*vm)->GetEnv(vm, (void **) &env, JNI_VERSION_1_6);

if (getEnvResult != JNI_OK)

{

return;

}

// Cleanup all global references.

(*env)->DeleteGlobalRef(env, jClassLibUsb);

}

/**

* Wrap a C pointer with a wrapper Java class and returns the instance of

* this wrapper class. When the C pointer is null or the wrapper class could

* not be created then NULL is returned.

*

* @param env

* The JNI environment.

* @param ptr

* The C pointer to wrap.

* @param className

* The class name of the wrapper class.

* @param fieldName

* The field name for storing the pointer in the wrapper class.

* @return The instance of the wrapper class or null if C pointer is null or

* the wrapper class could not be created.

*/

jobject wrapPointer(JNIEnv *env, const void *ptr, const char *className,

const char *fieldName)

{

jclass cls;

jmethodID constructor;

jobject object;

jfieldID field;

if (!ptr) return NULL;

cls = (*env)->FindClass(env, className);

if (cls == NULL) return NULL;

constructor = (*env)->GetMethodID(env, cls, "<init>", "()V");

if (!constructor) return NULL;

object = (*env)->NewObject(env, cls, constructor);

field = (*env)->GetFieldID(env, cls, fieldName, "J");

(*env)->SetLongField(env, object, field, (jptr) ptr);

return object;

}

/**

* Unwraps a C pointer from a Java wrapper object.

*

* @param env

* The JNI environment.

* @param object

* The Java wrapper object.

* @param fieldName

* The field name where the C pointer is stored in the wrapper

* object.

* @return The C pointer.

*/

void * unwrapPointer(JNIEnv *env, jobject object, const char *fieldName)

{

jptr ptr;

jclass cls;

jfieldID field;

if (!object) return NULL;

cls = (*env)->GetObjectClass(env, object);

field = (*env)->GetFieldID(env, cls, fieldName, "J");

ptr = (jptr) (*env)->GetLongField(env, object, field);

if (!ptr) illegalState(env, "%s is not initialized", fieldName);

return (void *) ptr;

}