media/jni/android_mtp_MtpDevice.cpp - LeafOS-Project/android_frameworks_base - Gitiles

 /*
  * Copyright (C) 2010 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 // #define LOG_NDEBUG 0

 #define LOG_TAG "MtpDeviceJNI"
 #include "utils/Log.h"

 #include <stdio.h>
 #include <assert.h>
 #include <limits.h>
 #include <unistd.h>
 #include <fcntl.h>

 #include "jni.h"
 #include "JNIHelp.h"
 #include "android_runtime/AndroidRuntime.h"
 #include "android_runtime/Log.h"
 #include "private/android_filesystem_config.h"

 #include "MtpTypes.h"
 #include "MtpDevice.h"
 #include "MtpDeviceInfo.h"
 #include "MtpStorageInfo.h"
 #include "MtpObjectInfo.h"

 using namespace android;

 // ----------------------------------------------------------------------------

 static jfieldID field_context;

 jclass clazz_deviceInfo;
 jclass clazz_storageInfo;
 jclass clazz_objectInfo;

 jmethodID constructor_deviceInfo;
 jmethodID constructor_storageInfo;
 jmethodID constructor_objectInfo;

 // MtpDeviceInfo fields
 static jfieldID field_deviceInfo_manufacturer;
 static jfieldID field_deviceInfo_model;
 static jfieldID field_deviceInfo_version;
 static jfieldID field_deviceInfo_serialNumber;

 // MtpStorageInfo fields
 static jfieldID field_storageInfo_storageId;
 static jfieldID field_storageInfo_maxCapacity;
 static jfieldID field_storageInfo_freeSpace;
 static jfieldID field_storageInfo_description;
 static jfieldID field_storageInfo_volumeIdentifier;

 // MtpObjectInfo fields
 static jfieldID field_objectInfo_handle;
 static jfieldID field_objectInfo_storageId;
 static jfieldID field_objectInfo_format;
 static jfieldID field_objectInfo_protectionStatus;
 static jfieldID field_objectInfo_compressedSize;
 static jfieldID field_objectInfo_thumbFormat;
 static jfieldID field_objectInfo_thumbCompressedSize;
 static jfieldID field_objectInfo_thumbPixWidth;
 static jfieldID field_objectInfo_thumbPixHeight;
 static jfieldID field_objectInfo_imagePixWidth;
 static jfieldID field_objectInfo_imagePixHeight;
 static jfieldID field_objectInfo_imagePixDepth;
 static jfieldID field_objectInfo_parent;
 static jfieldID field_objectInfo_associationType;
 static jfieldID field_objectInfo_associationDesc;
 static jfieldID field_objectInfo_sequenceNumber;
 static jfieldID field_objectInfo_name;
 static jfieldID field_objectInfo_dateCreated;
 static jfieldID field_objectInfo_dateModified;
 static jfieldID field_objectInfo_keywords;

 MtpDevice* get_device_from_object(JNIEnv* env, jobject javaDevice)
 {
     return (MtpDevice*)env->GetLongField(javaDevice, field_context);
 }

 // ----------------------------------------------------------------------------

 static jboolean
 android_mtp_MtpDevice_open(JNIEnv *env, jobject thiz, jstring deviceName, jint fd)
 {
     const char *deviceNameStr = env->GetStringUTFChars(deviceName, NULL);
     if (deviceNameStr == NULL) {
         return JNI_FALSE;
     }

     MtpDevice* device = MtpDevice::open(deviceNameStr, fd);
     env->ReleaseStringUTFChars(deviceName, deviceNameStr);

     if (device)
         env->SetLongField(thiz, field_context,  (jlong)device);
     return (jboolean)(device != NULL);
 }

 static void
 android_mtp_MtpDevice_close(JNIEnv *env, jobject thiz)
 {
     MtpDevice* device = get_device_from_object(env, thiz);
     if (device) {
         device->close();
         delete device;
         env->SetLongField(thiz, field_context, 0);
     }
 }

 static jobject
 android_mtp_MtpDevice_get_device_info(JNIEnv *env, jobject thiz)
 {
     MtpDevice* device = get_device_from_object(env, thiz);
     if (!device) {
         ALOGD("android_mtp_MtpDevice_get_device_info device is null");
         return NULL;
     }
     MtpDeviceInfo* deviceInfo = device->getDeviceInfo();
     if (!deviceInfo) {
         ALOGD("android_mtp_MtpDevice_get_device_info deviceInfo is null");
         return NULL;
     }
     jobject info = env->NewObject(clazz_deviceInfo, constructor_deviceInfo);
     if (info == NULL) {
         ALOGE("Could not create a MtpDeviceInfo object");
         delete deviceInfo;
         return NULL;
     }

     if (deviceInfo->mManufacturer)
         env->SetObjectField(info, field_deviceInfo_manufacturer,
             env->NewStringUTF(deviceInfo->mManufacturer));
     if (deviceInfo->mModel)
         env->SetObjectField(info, field_deviceInfo_model,
             env->NewStringUTF(deviceInfo->mModel));
     if (deviceInfo->mVersion)
         env->SetObjectField(info, field_deviceInfo_version,
             env->NewStringUTF(deviceInfo->mVersion));
     if (deviceInfo->mSerial)
         env->SetObjectField(info, field_deviceInfo_serialNumber,
             env->NewStringUTF(deviceInfo->mSerial));

     delete deviceInfo;
     return info;
 }

 static jintArray
 android_mtp_MtpDevice_get_storage_ids(JNIEnv *env, jobject thiz)
 {
     MtpDevice* device = get_device_from_object(env, thiz);
     if (!device)
         return NULL;
     MtpStorageIDList* storageIDs = device->getStorageIDs();
     if (!storageIDs)
         return NULL;

     int length = storageIDs->size();
     jintArray array = env->NewIntArray(length);
     // FIXME is this cast safe?
     env->SetIntArrayRegion(array, 0, length, (const jint *)storageIDs->array());

     delete storageIDs;
     return array;
 }

 static jobject
 android_mtp_MtpDevice_get_storage_info(JNIEnv *env, jobject thiz, jint storageID)
 {
     MtpDevice* device = get_device_from_object(env, thiz);
     if (!device)
         return NULL;
     MtpStorageInfo* storageInfo = device->getStorageInfo(storageID);
     if (!storageInfo)
         return NULL;

     jobject info = env->NewObject(clazz_storageInfo, constructor_storageInfo);
     if (info == NULL) {
         ALOGE("Could not create a MtpStorageInfo object");
         delete storageInfo;
         return NULL;
     }

     if (storageInfo->mStorageID)
         env->SetIntField(info, field_storageInfo_storageId, storageInfo->mStorageID);
     if (storageInfo->mMaxCapacity)
         env->SetLongField(info, field_storageInfo_maxCapacity, storageInfo->mMaxCapacity);
     if (storageInfo->mFreeSpaceBytes)
         env->SetLongField(info, field_storageInfo_freeSpace, storageInfo->mFreeSpaceBytes);
     if (storageInfo->mStorageDescription)
         env->SetObjectField(info, field_storageInfo_description,
             env->NewStringUTF(storageInfo->mStorageDescription));
     if (storageInfo->mVolumeIdentifier)
         env->SetObjectField(info, field_storageInfo_volumeIdentifier,
             env->NewStringUTF(storageInfo->mVolumeIdentifier));

     delete storageInfo;
     return info;
 }

 static jintArray
 android_mtp_MtpDevice_get_object_handles(JNIEnv *env, jobject thiz,
         jint storageID, jint format, jint objectID)
 {
     MtpDevice* device = get_device_from_object(env, thiz);
     if (!device)
         return NULL;
     MtpObjectHandleList* handles = device->getObjectHandles(storageID, format, objectID);
     if (!handles)
         return NULL;

     int length = handles->size();
     jintArray array = env->NewIntArray(length);
     // FIXME is this cast safe?
     env->SetIntArrayRegion(array, 0, length, (const jint *)handles->array());

     delete handles;
     return array;
 }

 static jobject
 android_mtp_MtpDevice_get_object_info(JNIEnv *env, jobject thiz, jint objectID)
 {
     MtpDevice* device = get_device_from_object(env, thiz);
     if (!device)
         return NULL;
     MtpObjectInfo* objectInfo = device->getObjectInfo(objectID);
     if (!objectInfo)
         return NULL;
     jobject info = env->NewObject(clazz_objectInfo, constructor_objectInfo);
     if (info == NULL) {
         ALOGE("Could not create a MtpObjectInfo object");
         delete objectInfo;
         return NULL;
     }

     if (objectInfo->mHandle)
         env->SetIntField(info, field_objectInfo_handle, objectInfo->mHandle);
     if (objectInfo->mStorageID)
         env->SetIntField(info, field_objectInfo_storageId, objectInfo->mStorageID);
     if (objectInfo->mFormat)
         env->SetIntField(info, field_objectInfo_format, objectInfo->mFormat);
     if (objectInfo->mProtectionStatus)
         env->SetIntField(info, field_objectInfo_protectionStatus, objectInfo->mProtectionStatus);
     if (objectInfo->mCompressedSize)
         env->SetIntField(info, field_objectInfo_compressedSize, objectInfo->mCompressedSize);
     if (objectInfo->mThumbFormat)
         env->SetIntField(info, field_objectInfo_thumbFormat, objectInfo->mThumbFormat);
     if (objectInfo->mThumbCompressedSize)
         env->SetIntField(info, field_objectInfo_thumbCompressedSize, objectInfo->mThumbCompressedSize);
     if (objectInfo->mThumbPixWidth)
         env->SetIntField(info, field_objectInfo_thumbPixWidth, objectInfo->mThumbPixWidth);
     if (objectInfo->mThumbPixHeight)
         env->SetIntField(info, field_objectInfo_thumbPixHeight, objectInfo->mThumbPixHeight);
     if (objectInfo->mImagePixWidth)
         env->SetIntField(info, field_objectInfo_imagePixWidth, objectInfo->mImagePixWidth);
     if (objectInfo->mImagePixHeight)
         env->SetIntField(info, field_objectInfo_imagePixHeight, objectInfo->mImagePixHeight);
     if (objectInfo->mImagePixDepth)
         env->SetIntField(info, field_objectInfo_imagePixDepth, objectInfo->mImagePixDepth);
     if (objectInfo->mParent)
         env->SetIntField(info, field_objectInfo_parent, objectInfo->mParent);
     if (objectInfo->mAssociationType)
         env->SetIntField(info, field_objectInfo_associationType, objectInfo->mAssociationType);
     if (objectInfo->mAssociationDesc)
         env->SetIntField(info, field_objectInfo_associationDesc, objectInfo->mAssociationDesc);
     if (objectInfo->mSequenceNumber)
         env->SetIntField(info, field_objectInfo_sequenceNumber, objectInfo->mSequenceNumber);
     if (objectInfo->mName)
         env->SetObjectField(info, field_objectInfo_name, env->NewStringUTF(objectInfo->mName));
     if (objectInfo->mDateCreated)
         env->SetLongField(info, field_objectInfo_dateCreated, objectInfo->mDateCreated * 1000LL);
     if (objectInfo->mDateModified)
         env->SetLongField(info, field_objectInfo_dateModified, objectInfo->mDateModified * 1000LL);
     if (objectInfo->mKeywords)
         env->SetObjectField(info, field_objectInfo_keywords,
             env->NewStringUTF(objectInfo->mKeywords));

     delete objectInfo;
     return info;
 }

 struct get_object_callback_data {
     JNIEnv *env;
     jbyteArray array;
 };

 static bool get_object_callback(void* data, int offset, int length, void* clientData)
 {
     get_object_callback_data* cbData = (get_object_callback_data *)clientData;
     cbData->env->SetByteArrayRegion(cbData->array, offset, length, (jbyte *)data);
     return true;
 }

 static jbyteArray
 android_mtp_MtpDevice_get_object(JNIEnv *env, jobject thiz, jint objectID, jint objectSize)
 {
     MtpDevice* device = get_device_from_object(env, thiz);
     if (!device)
         return NULL;

     jbyteArray array = env->NewByteArray(objectSize);
     if (!array) {
         jniThrowException(env, "java/lang/OutOfMemoryError", NULL);
         return NULL;
     }

     get_object_callback_data data;
     data.env = env;
     data.array = array;

     if (device->readObject(objectID, get_object_callback, objectSize, &data))
         return array;
     return NULL;
 }

 static jbyteArray
 android_mtp_MtpDevice_get_thumbnail(JNIEnv *env, jobject thiz, jint objectID)
 {
     MtpDevice* device = get_device_from_object(env, thiz);
     if (!device)
         return NULL;

     int length;
     void* thumbnail = device->getThumbnail(objectID, length);
     if (! thumbnail)
         return NULL;
     jbyteArray array = env->NewByteArray(length);
     env->SetByteArrayRegion(array, 0, length, (const jbyte *)thumbnail);

     free(thumbnail);
     return array;
 }

 static jboolean
 android_mtp_MtpDevice_delete_object(JNIEnv *env, jobject thiz, jint object_id)
 {
     MtpDevice* device = get_device_from_object(env, thiz);
     if (device && device->deleteObject(object_id)) {
         return JNI_TRUE;
     } else {
         return JNI_FALSE;
     }
 }

 static jlong
 android_mtp_MtpDevice_get_parent(JNIEnv *env, jobject thiz, jint object_id)
 {
     MtpDevice* device = get_device_from_object(env, thiz);
     if (device)
         return (jlong)device->getParent(object_id);
     else
         return -1;
 }

 static jlong
 android_mtp_MtpDevice_get_storage_id(JNIEnv *env, jobject thiz, jint object_id)
 {
     MtpDevice* device = get_device_from_object(env, thiz);
     if (device)
         return (jlong)device->getStorageID(object_id);
     else
         return -1;
 }

 static jboolean
 android_mtp_MtpDevice_import_file(JNIEnv *env, jobject thiz, jint object_id, jstring dest_path)
 {
     MtpDevice* device = get_device_from_object(env, thiz);
     if (device) {
         const char *destPathStr = env->GetStringUTFChars(dest_path, NULL);
         if (destPathStr == NULL) {
             return JNI_FALSE;
         }

         jboolean result = device->readObject(object_id, destPathStr, AID_SDCARD_RW, 0664);
         env->ReleaseStringUTFChars(dest_path, destPathStr);
         return result;
     }

     return JNI_FALSE;
 }

 // ----------------------------------------------------------------------------

 static const JNINativeMethod gMethods[] = {
     {"native_open",             "(Ljava/lang/String;I)Z",
                                         (void *)android_mtp_MtpDevice_open},
     {"native_close",            "()V",  (void *)android_mtp_MtpDevice_close},
     {"native_get_device_info",  "()Landroid/mtp/MtpDeviceInfo;",
                                         (void *)android_mtp_MtpDevice_get_device_info},
     {"native_get_storage_ids",  "()[I", (void *)android_mtp_MtpDevice_get_storage_ids},
     {"native_get_storage_info", "(I)Landroid/mtp/MtpStorageInfo;",
                                         (void *)android_mtp_MtpDevice_get_storage_info},
     {"native_get_object_handles","(III)[I",
                                         (void *)android_mtp_MtpDevice_get_object_handles},
     {"native_get_object_info",  "(I)Landroid/mtp/MtpObjectInfo;",
                                         (void *)android_mtp_MtpDevice_get_object_info},
     {"native_get_object",       "(II)[B",(void *)android_mtp_MtpDevice_get_object},
     {"native_get_thumbnail",    "(I)[B",(void *)android_mtp_MtpDevice_get_thumbnail},
     {"native_delete_object",    "(I)Z", (void *)android_mtp_MtpDevice_delete_object},
     {"native_get_parent",       "(I)J", (void *)android_mtp_MtpDevice_get_parent},
     {"native_get_storage_id",   "(I)J", (void *)android_mtp_MtpDevice_get_storage_id},
     {"native_import_file",     "(ILjava/lang/String;)Z",
                                         (void *)android_mtp_MtpDevice_import_file},
 };

 int register_android_mtp_MtpDevice(JNIEnv *env)
 {
     jclass clazz;

     ALOGD("register_android_mtp_MtpDevice\n");

     clazz = env->FindClass("android/mtp/MtpDeviceInfo");
     if (clazz == NULL) {
         ALOGE("Can't find android/mtp/MtpDeviceInfo");
         return -1;
     }
     constructor_deviceInfo = env->GetMethodID(clazz, "<init>", "()V");
     if (constructor_deviceInfo == NULL) {
         ALOGE("Can't find android/mtp/MtpDeviceInfo constructor");
         return -1;
     }
     field_deviceInfo_manufacturer = env->GetFieldID(clazz, "mManufacturer", "Ljava/lang/String;");
     if (field_deviceInfo_manufacturer == NULL) {
         ALOGE("Can't find MtpDeviceInfo.mManufacturer");
         return -1;
     }
     field_deviceInfo_model = env->GetFieldID(clazz, "mModel", "Ljava/lang/String;");
     if (field_deviceInfo_model == NULL) {
         ALOGE("Can't find MtpDeviceInfo.mModel");
         return -1;
     }
     field_deviceInfo_version = env->GetFieldID(clazz, "mVersion", "Ljava/lang/String;");
     if (field_deviceInfo_version == NULL) {
         ALOGE("Can't find MtpDeviceInfo.mVersion");
         return -1;
     }
     field_deviceInfo_serialNumber = env->GetFieldID(clazz, "mSerialNumber", "Ljava/lang/String;");
     if (field_deviceInfo_serialNumber == NULL) {
         ALOGE("Can't find MtpDeviceInfo.mSerialNumber");
         return -1;
     }
     clazz_deviceInfo = (jclass)env->NewGlobalRef(clazz);

     clazz = env->FindClass("android/mtp/MtpStorageInfo");
     if (clazz == NULL) {
         ALOGE("Can't find android/mtp/MtpStorageInfo");
         return -1;
     }
     constructor_storageInfo = env->GetMethodID(clazz, "<init>", "()V");
     if (constructor_storageInfo == NULL) {
         ALOGE("Can't find android/mtp/MtpStorageInfo constructor");
         return -1;
     }
     field_storageInfo_storageId = env->GetFieldID(clazz, "mStorageId", "I");
     if (field_storageInfo_storageId == NULL) {
         ALOGE("Can't find MtpStorageInfo.mStorageId");
         return -1;
     }
     field_storageInfo_maxCapacity = env->GetFieldID(clazz, "mMaxCapacity", "J");
     if (field_storageInfo_maxCapacity == NULL) {
         ALOGE("Can't find MtpStorageInfo.mMaxCapacity");
         return -1;
     }
     field_storageInfo_freeSpace = env->GetFieldID(clazz, "mFreeSpace", "J");
     if (field_storageInfo_freeSpace == NULL) {
         ALOGE("Can't find MtpStorageInfo.mFreeSpace");
         return -1;
     }
     field_storageInfo_description = env->GetFieldID(clazz, "mDescription", "Ljava/lang/String;");
     if (field_storageInfo_description == NULL) {
         ALOGE("Can't find MtpStorageInfo.mDescription");
         return -1;
     }
     field_storageInfo_volumeIdentifier = env->GetFieldID(clazz, "mVolumeIdentifier", "Ljava/lang/String;");
     if (field_storageInfo_volumeIdentifier == NULL) {
         ALOGE("Can't find MtpStorageInfo.mVolumeIdentifier");
         return -1;
     }
     clazz_storageInfo = (jclass)env->NewGlobalRef(clazz);

     clazz = env->FindClass("android/mtp/MtpObjectInfo");
     if (clazz == NULL) {
         ALOGE("Can't find android/mtp/MtpObjectInfo");
         return -1;
     }
     constructor_objectInfo = env->GetMethodID(clazz, "<init>", "()V");
     if (constructor_objectInfo == NULL) {
         ALOGE("Can't find android/mtp/MtpObjectInfo constructor");
         return -1;
     }
     field_objectInfo_handle = env->GetFieldID(clazz, "mHandle", "I");
     if (field_objectInfo_handle == NULL) {
         ALOGE("Can't find MtpObjectInfo.mHandle");
         return -1;
     }
     field_objectInfo_storageId = env->GetFieldID(clazz, "mStorageId", "I");
     if (field_objectInfo_storageId == NULL) {
         ALOGE("Can't find MtpObjectInfo.mStorageId");
         return -1;
     }
     field_objectInfo_format = env->GetFieldID(clazz, "mFormat", "I");
     if (field_objectInfo_format == NULL) {
         ALOGE("Can't find MtpObjectInfo.mFormat");
         return -1;
     }
     field_objectInfo_protectionStatus = env->GetFieldID(clazz, "mProtectionStatus", "I");
     if (field_objectInfo_protectionStatus == NULL) {
         ALOGE("Can't find MtpObjectInfo.mProtectionStatus");
         return -1;
     }
     field_objectInfo_compressedSize = env->GetFieldID(clazz, "mCompressedSize", "I");
     if (field_objectInfo_compressedSize == NULL) {
         ALOGE("Can't find MtpObjectInfo.mCompressedSize");
         return -1;
     }
     field_objectInfo_thumbFormat = env->GetFieldID(clazz, "mThumbFormat", "I");
     if (field_objectInfo_thumbFormat == NULL) {
         ALOGE("Can't find MtpObjectInfo.mThumbFormat");
         return -1;
     }
     field_objectInfo_thumbCompressedSize = env->GetFieldID(clazz, "mThumbCompressedSize", "I");
     if (field_objectInfo_thumbCompressedSize == NULL) {
         ALOGE("Can't find MtpObjectInfo.mThumbCompressedSize");
         return -1;
     }
     field_objectInfo_thumbPixWidth = env->GetFieldID(clazz, "mThumbPixWidth", "I");
     if (field_objectInfo_thumbPixWidth == NULL) {
         ALOGE("Can't find MtpObjectInfo.mThumbPixWidth");
         return -1;
     }
     field_objectInfo_thumbPixHeight = env->GetFieldID(clazz, "mThumbPixHeight", "I");
     if (field_objectInfo_thumbPixHeight == NULL) {
         ALOGE("Can't find MtpObjectInfo.mThumbPixHeight");
         return -1;
     }
     field_objectInfo_imagePixWidth = env->GetFieldID(clazz, "mImagePixWidth", "I");
     if (field_objectInfo_imagePixWidth == NULL) {
         ALOGE("Can't find MtpObjectInfo.mImagePixWidth");
         return -1;
     }
     field_objectInfo_imagePixHeight = env->GetFieldID(clazz, "mImagePixHeight", "I");
     if (field_objectInfo_imagePixHeight == NULL) {
         ALOGE("Can't find MtpObjectInfo.mImagePixHeight");
         return -1;
     }
     field_objectInfo_imagePixDepth = env->GetFieldID(clazz, "mImagePixDepth", "I");
     if (field_objectInfo_imagePixDepth == NULL) {
         ALOGE("Can't find MtpObjectInfo.mImagePixDepth");
         return -1;
     }
     field_objectInfo_parent = env->GetFieldID(clazz, "mParent", "I");
     if (field_objectInfo_parent == NULL) {
         ALOGE("Can't find MtpObjectInfo.mParent");
         return -1;
     }
     field_objectInfo_associationType = env->GetFieldID(clazz, "mAssociationType", "I");
     if (field_objectInfo_associationType == NULL) {
         ALOGE("Can't find MtpObjectInfo.mAssociationType");
         return -1;
     }
     field_objectInfo_associationDesc = env->GetFieldID(clazz, "mAssociationDesc", "I");
     if (field_objectInfo_associationDesc == NULL) {
         ALOGE("Can't find MtpObjectInfo.mAssociationDesc");
         return -1;
     }
     field_objectInfo_sequenceNumber = env->GetFieldID(clazz, "mSequenceNumber", "I");
     if (field_objectInfo_sequenceNumber == NULL) {
         ALOGE("Can't find MtpObjectInfo.mSequenceNumber");
         return -1;
     }
     field_objectInfo_name = env->GetFieldID(clazz, "mName", "Ljava/lang/String;");
     if (field_objectInfo_name == NULL) {
         ALOGE("Can't find MtpObjectInfo.mName");
         return -1;
     }
     field_objectInfo_dateCreated = env->GetFieldID(clazz, "mDateCreated", "J");
     if (field_objectInfo_dateCreated == NULL) {
         ALOGE("Can't find MtpObjectInfo.mDateCreated");
         return -1;
     }
     field_objectInfo_dateModified = env->GetFieldID(clazz, "mDateModified", "J");
     if (field_objectInfo_dateModified == NULL) {
         ALOGE("Can't find MtpObjectInfo.mDateModified");
         return -1;
     }
     field_objectInfo_keywords = env->GetFieldID(clazz, "mKeywords", "Ljava/lang/String;");
     if (field_objectInfo_keywords == NULL) {
         ALOGE("Can't find MtpObjectInfo.mKeywords");
         return -1;
     }
     clazz_objectInfo = (jclass)env->NewGlobalRef(clazz);

     clazz = env->FindClass("android/mtp/MtpDevice");
     if (clazz == NULL) {
         ALOGE("Can't find android/mtp/MtpDevice");
         return -1;
     }
     field_context = env->GetFieldID(clazz, "mNativeContext", "J");
     if (field_context == NULL) {
         ALOGE("Can't find MtpDevice.mNativeContext");
         return -1;
     }

     return AndroidRuntime::registerNativeMethods(env,
                 "android/mtp/MtpDevice", gMethods, NELEM(gMethods));
 }
	/*
	* Copyright (C) 2010 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	// #define LOG_NDEBUG 0

	#define LOG_TAG "MtpDeviceJNI"
	#include "utils/Log.h"

	#include <stdio.h>
	#include <assert.h>
	#include <limits.h>
	#include <unistd.h>
	#include <fcntl.h>

	#include "jni.h"
	#include "JNIHelp.h"
	#include "android_runtime/AndroidRuntime.h"
	#include "android_runtime/Log.h"
	#include "private/android_filesystem_config.h"

	#include "MtpTypes.h"
	#include "MtpDevice.h"
	#include "MtpDeviceInfo.h"
	#include "MtpStorageInfo.h"
	#include "MtpObjectInfo.h"

	using namespace android;

	// ----------------------------------------------------------------------------

	static jfieldID field_context;

	jclass clazz_deviceInfo;
	jclass clazz_storageInfo;
	jclass clazz_objectInfo;

	jmethodID constructor_deviceInfo;
	jmethodID constructor_storageInfo;
	jmethodID constructor_objectInfo;

	// MtpDeviceInfo fields
	static jfieldID field_deviceInfo_manufacturer;
	static jfieldID field_deviceInfo_model;
	static jfieldID field_deviceInfo_version;
	static jfieldID field_deviceInfo_serialNumber;

	// MtpStorageInfo fields
	static jfieldID field_storageInfo_storageId;
	static jfieldID field_storageInfo_maxCapacity;
	static jfieldID field_storageInfo_freeSpace;
	static jfieldID field_storageInfo_description;
	static jfieldID field_storageInfo_volumeIdentifier;

	// MtpObjectInfo fields
	static jfieldID field_objectInfo_handle;
	static jfieldID field_objectInfo_storageId;
	static jfieldID field_objectInfo_format;
	static jfieldID field_objectInfo_protectionStatus;
	static jfieldID field_objectInfo_compressedSize;
	static jfieldID field_objectInfo_thumbFormat;
	static jfieldID field_objectInfo_thumbCompressedSize;
	static jfieldID field_objectInfo_thumbPixWidth;
	static jfieldID field_objectInfo_thumbPixHeight;
	static jfieldID field_objectInfo_imagePixWidth;
	static jfieldID field_objectInfo_imagePixHeight;
	static jfieldID field_objectInfo_imagePixDepth;
	static jfieldID field_objectInfo_parent;
	static jfieldID field_objectInfo_associationType;
	static jfieldID field_objectInfo_associationDesc;
	static jfieldID field_objectInfo_sequenceNumber;
	static jfieldID field_objectInfo_name;
	static jfieldID field_objectInfo_dateCreated;
	static jfieldID field_objectInfo_dateModified;
	static jfieldID field_objectInfo_keywords;

	MtpDevice* get_device_from_object(JNIEnv* env, jobject javaDevice)
	{
	return (MtpDevice*)env->GetLongField(javaDevice, field_context);
	}

	// ----------------------------------------------------------------------------

	static jboolean
	android_mtp_MtpDevice_open(JNIEnv *env, jobject thiz, jstring deviceName, jint fd)
	{
	const char *deviceNameStr = env->GetStringUTFChars(deviceName, NULL);
	if (deviceNameStr == NULL) {
	return JNI_FALSE;
	}

	MtpDevice* device = MtpDevice::open(deviceNameStr, fd);
	env->ReleaseStringUTFChars(deviceName, deviceNameStr);

	if (device)
	env->SetLongField(thiz, field_context, (jlong)device);
	return (jboolean)(device != NULL);
	}

	static void
	android_mtp_MtpDevice_close(JNIEnv *env, jobject thiz)
	{
	MtpDevice* device = get_device_from_object(env, thiz);
	if (device) {
	device->close();
	delete device;
	env->SetLongField(thiz, field_context, 0);
	}
	}

	static jobject
	android_mtp_MtpDevice_get_device_info(JNIEnv *env, jobject thiz)
	{
	MtpDevice* device = get_device_from_object(env, thiz);
	if (!device) {
	ALOGD("android_mtp_MtpDevice_get_device_info device is null");
	return NULL;
	}
	MtpDeviceInfo* deviceInfo = device->getDeviceInfo();
	if (!deviceInfo) {
	ALOGD("android_mtp_MtpDevice_get_device_info deviceInfo is null");
	return NULL;
	}
	jobject info = env->NewObject(clazz_deviceInfo, constructor_deviceInfo);
	if (info == NULL) {
	ALOGE("Could not create a MtpDeviceInfo object");
	delete deviceInfo;
	return NULL;
	}

	if (deviceInfo->mManufacturer)
	env->SetObjectField(info, field_deviceInfo_manufacturer,
	env->NewStringUTF(deviceInfo->mManufacturer));
	if (deviceInfo->mModel)
	env->SetObjectField(info, field_deviceInfo_model,
	env->NewStringUTF(deviceInfo->mModel));
	if (deviceInfo->mVersion)
	env->SetObjectField(info, field_deviceInfo_version,
	env->NewStringUTF(deviceInfo->mVersion));
	if (deviceInfo->mSerial)
	env->SetObjectField(info, field_deviceInfo_serialNumber,
	env->NewStringUTF(deviceInfo->mSerial));

	delete deviceInfo;
	return info;
	}

	static jintArray
	android_mtp_MtpDevice_get_storage_ids(JNIEnv *env, jobject thiz)
	{
	MtpDevice* device = get_device_from_object(env, thiz);
	if (!device)
	return NULL;
	MtpStorageIDList* storageIDs = device->getStorageIDs();
	if (!storageIDs)
	return NULL;

	int length = storageIDs->size();
	jintArray array = env->NewIntArray(length);
	// FIXME is this cast safe?
	env->SetIntArrayRegion(array, 0, length, (const jint *)storageIDs->array());

	delete storageIDs;
	return array;
	}

	static jobject
	android_mtp_MtpDevice_get_storage_info(JNIEnv *env, jobject thiz, jint storageID)
	{
	MtpDevice* device = get_device_from_object(env, thiz);
	if (!device)
	return NULL;
	MtpStorageInfo* storageInfo = device->getStorageInfo(storageID);
	if (!storageInfo)
	return NULL;

	jobject info = env->NewObject(clazz_storageInfo, constructor_storageInfo);
	if (info == NULL) {
	ALOGE("Could not create a MtpStorageInfo object");
	delete storageInfo;
	return NULL;
	}

	if (storageInfo->mStorageID)
	env->SetIntField(info, field_storageInfo_storageId, storageInfo->mStorageID);
	if (storageInfo->mMaxCapacity)
	env->SetLongField(info, field_storageInfo_maxCapacity, storageInfo->mMaxCapacity);
	if (storageInfo->mFreeSpaceBytes)
	env->SetLongField(info, field_storageInfo_freeSpace, storageInfo->mFreeSpaceBytes);
	if (storageInfo->mStorageDescription)
	env->SetObjectField(info, field_storageInfo_description,
	env->NewStringUTF(storageInfo->mStorageDescription));
	if (storageInfo->mVolumeIdentifier)
	env->SetObjectField(info, field_storageInfo_volumeIdentifier,
	env->NewStringUTF(storageInfo->mVolumeIdentifier));

	delete storageInfo;
	return info;
	}

	static jintArray
	android_mtp_MtpDevice_get_object_handles(JNIEnv *env, jobject thiz,
	jint storageID, jint format, jint objectID)
	{
	MtpDevice* device = get_device_from_object(env, thiz);
	if (!device)
	return NULL;
	MtpObjectHandleList* handles = device->getObjectHandles(storageID, format, objectID);
	if (!handles)
	return NULL;

	int length = handles->size();
	jintArray array = env->NewIntArray(length);
	// FIXME is this cast safe?
	env->SetIntArrayRegion(array, 0, length, (const jint *)handles->array());

	delete handles;
	return array;
	}

	static jobject
	android_mtp_MtpDevice_get_object_info(JNIEnv *env, jobject thiz, jint objectID)
	{
	MtpDevice* device = get_device_from_object(env, thiz);
	if (!device)
	return NULL;
	MtpObjectInfo* objectInfo = device->getObjectInfo(objectID);
	if (!objectInfo)
	return NULL;
	jobject info = env->NewObject(clazz_objectInfo, constructor_objectInfo);
	if (info == NULL) {
	ALOGE("Could not create a MtpObjectInfo object");
	delete objectInfo;
	return NULL;
	}

	if (objectInfo->mHandle)
	env->SetIntField(info, field_objectInfo_handle, objectInfo->mHandle);
	if (objectInfo->mStorageID)
	env->SetIntField(info, field_objectInfo_storageId, objectInfo->mStorageID);
	if (objectInfo->mFormat)
	env->SetIntField(info, field_objectInfo_format, objectInfo->mFormat);
	if (objectInfo->mProtectionStatus)
	env->SetIntField(info, field_objectInfo_protectionStatus, objectInfo->mProtectionStatus);
	if (objectInfo->mCompressedSize)
	env->SetIntField(info, field_objectInfo_compressedSize, objectInfo->mCompressedSize);
	if (objectInfo->mThumbFormat)
	env->SetIntField(info, field_objectInfo_thumbFormat, objectInfo->mThumbFormat);
	if (objectInfo->mThumbCompressedSize)
	env->SetIntField(info, field_objectInfo_thumbCompressedSize, objectInfo->mThumbCompressedSize);
	if (objectInfo->mThumbPixWidth)
	env->SetIntField(info, field_objectInfo_thumbPixWidth, objectInfo->mThumbPixWidth);
	if (objectInfo->mThumbPixHeight)
	env->SetIntField(info, field_objectInfo_thumbPixHeight, objectInfo->mThumbPixHeight);
	if (objectInfo->mImagePixWidth)
	env->SetIntField(info, field_objectInfo_imagePixWidth, objectInfo->mImagePixWidth);
	if (objectInfo->mImagePixHeight)
	env->SetIntField(info, field_objectInfo_imagePixHeight, objectInfo->mImagePixHeight);
	if (objectInfo->mImagePixDepth)
	env->SetIntField(info, field_objectInfo_imagePixDepth, objectInfo->mImagePixDepth);
	if (objectInfo->mParent)
	env->SetIntField(info, field_objectInfo_parent, objectInfo->mParent);
	if (objectInfo->mAssociationType)
	env->SetIntField(info, field_objectInfo_associationType, objectInfo->mAssociationType);
	if (objectInfo->mAssociationDesc)
	env->SetIntField(info, field_objectInfo_associationDesc, objectInfo->mAssociationDesc);
	if (objectInfo->mSequenceNumber)
	env->SetIntField(info, field_objectInfo_sequenceNumber, objectInfo->mSequenceNumber);
	if (objectInfo->mName)
	env->SetObjectField(info, field_objectInfo_name, env->NewStringUTF(objectInfo->mName));
	if (objectInfo->mDateCreated)
	env->SetLongField(info, field_objectInfo_dateCreated, objectInfo->mDateCreated * 1000LL);
	if (objectInfo->mDateModified)
	env->SetLongField(info, field_objectInfo_dateModified, objectInfo->mDateModified * 1000LL);
	if (objectInfo->mKeywords)
	env->SetObjectField(info, field_objectInfo_keywords,
	env->NewStringUTF(objectInfo->mKeywords));

	delete objectInfo;
	return info;
	}

	struct get_object_callback_data {
	JNIEnv *env;
	jbyteArray array;
	};

	static bool get_object_callback(void* data, int offset, int length, void* clientData)
	{
	get_object_callback_data* cbData = (get_object_callback_data *)clientData;
	cbData->env->SetByteArrayRegion(cbData->array, offset, length, (jbyte *)data);
	return true;
	}

	static jbyteArray
	android_mtp_MtpDevice_get_object(JNIEnv *env, jobject thiz, jint objectID, jint objectSize)
	{
	MtpDevice* device = get_device_from_object(env, thiz);
	if (!device)
	return NULL;

	jbyteArray array = env->NewByteArray(objectSize);
	if (!array) {
	jniThrowException(env, "java/lang/OutOfMemoryError", NULL);
	return NULL;
	}

	get_object_callback_data data;
	data.env = env;
	data.array = array;

	if (device->readObject(objectID, get_object_callback, objectSize, &data))
	return array;
	return NULL;
	}

	static jbyteArray
	android_mtp_MtpDevice_get_thumbnail(JNIEnv *env, jobject thiz, jint objectID)
	{
	MtpDevice* device = get_device_from_object(env, thiz);
	if (!device)
	return NULL;

	int length;
	void* thumbnail = device->getThumbnail(objectID, length);
	if (! thumbnail)
	return NULL;
	jbyteArray array = env->NewByteArray(length);
	env->SetByteArrayRegion(array, 0, length, (const jbyte *)thumbnail);

	free(thumbnail);
	return array;
	}

	static jboolean
	android_mtp_MtpDevice_delete_object(JNIEnv *env, jobject thiz, jint object_id)
	{
	MtpDevice* device = get_device_from_object(env, thiz);
	if (device && device->deleteObject(object_id)) {
	return JNI_TRUE;
	} else {
	return JNI_FALSE;
	}
	}

	static jlong
	android_mtp_MtpDevice_get_parent(JNIEnv *env, jobject thiz, jint object_id)
	{
	MtpDevice* device = get_device_from_object(env, thiz);
	if (device)
	return (jlong)device->getParent(object_id);
	else
	return -1;
	}

	static jlong
	android_mtp_MtpDevice_get_storage_id(JNIEnv *env, jobject thiz, jint object_id)
	{
	MtpDevice* device = get_device_from_object(env, thiz);
	if (device)
	return (jlong)device->getStorageID(object_id);
	else
	return -1;
	}

	static jboolean
	android_mtp_MtpDevice_import_file(JNIEnv *env, jobject thiz, jint object_id, jstring dest_path)
	{
	MtpDevice* device = get_device_from_object(env, thiz);
	if (device) {
	const char *destPathStr = env->GetStringUTFChars(dest_path, NULL);
	if (destPathStr == NULL) {
	return JNI_FALSE;
	}

	jboolean result = device->readObject(object_id, destPathStr, AID_SDCARD_RW, 0664);
	env->ReleaseStringUTFChars(dest_path, destPathStr);
	return result;
	}

	return JNI_FALSE;
	}

	// ----------------------------------------------------------------------------

	static const JNINativeMethod gMethods[] = {
	{"native_open", "(Ljava/lang/String;I)Z",
	(void *)android_mtp_MtpDevice_open},
	{"native_close", "()V", (void *)android_mtp_MtpDevice_close},
	{"native_get_device_info", "()Landroid/mtp/MtpDeviceInfo;",
	(void *)android_mtp_MtpDevice_get_device_info},
	{"native_get_storage_ids", "()[I", (void *)android_mtp_MtpDevice_get_storage_ids},
	{"native_get_storage_info", "(I)Landroid/mtp/MtpStorageInfo;",
	(void *)android_mtp_MtpDevice_get_storage_info},
	{"native_get_object_handles","(III)[I",
	(void *)android_mtp_MtpDevice_get_object_handles},
	{"native_get_object_info", "(I)Landroid/mtp/MtpObjectInfo;",
	(void *)android_mtp_MtpDevice_get_object_info},
	{"native_get_object", "(II)[B",(void *)android_mtp_MtpDevice_get_object},
	{"native_get_thumbnail", "(I)[B",(void *)android_mtp_MtpDevice_get_thumbnail},
	{"native_delete_object", "(I)Z", (void *)android_mtp_MtpDevice_delete_object},
	{"native_get_parent", "(I)J", (void *)android_mtp_MtpDevice_get_parent},
	{"native_get_storage_id", "(I)J", (void *)android_mtp_MtpDevice_get_storage_id},
	{"native_import_file", "(ILjava/lang/String;)Z",
	(void *)android_mtp_MtpDevice_import_file},
	};

	int register_android_mtp_MtpDevice(JNIEnv *env)
	{
	jclass clazz;

	ALOGD("register_android_mtp_MtpDevice\n");

	clazz = env->FindClass("android/mtp/MtpDeviceInfo");
	if (clazz == NULL) {
	ALOGE("Can't find android/mtp/MtpDeviceInfo");
	return -1;
	}
	constructor_deviceInfo = env->GetMethodID(clazz, "<init>", "()V");
	if (constructor_deviceInfo == NULL) {
	ALOGE("Can't find android/mtp/MtpDeviceInfo constructor");
	return -1;
	}
	field_deviceInfo_manufacturer = env->GetFieldID(clazz, "mManufacturer", "Ljava/lang/String;");
	if (field_deviceInfo_manufacturer == NULL) {
	ALOGE("Can't find MtpDeviceInfo.mManufacturer");
	return -1;
	}
	field_deviceInfo_model = env->GetFieldID(clazz, "mModel", "Ljava/lang/String;");
	if (field_deviceInfo_model == NULL) {
	ALOGE("Can't find MtpDeviceInfo.mModel");
	return -1;
	}
	field_deviceInfo_version = env->GetFieldID(clazz, "mVersion", "Ljava/lang/String;");
	if (field_deviceInfo_version == NULL) {
	ALOGE("Can't find MtpDeviceInfo.mVersion");
	return -1;
	}
	field_deviceInfo_serialNumber = env->GetFieldID(clazz, "mSerialNumber", "Ljava/lang/String;");
	if (field_deviceInfo_serialNumber == NULL) {
	ALOGE("Can't find MtpDeviceInfo.mSerialNumber");
	return -1;
	}
	clazz_deviceInfo = (jclass)env->NewGlobalRef(clazz);

	clazz = env->FindClass("android/mtp/MtpStorageInfo");
	if (clazz == NULL) {
	ALOGE("Can't find android/mtp/MtpStorageInfo");
	return -1;
	}
	constructor_storageInfo = env->GetMethodID(clazz, "<init>", "()V");
	if (constructor_storageInfo == NULL) {
	ALOGE("Can't find android/mtp/MtpStorageInfo constructor");
	return -1;
	}
	field_storageInfo_storageId = env->GetFieldID(clazz, "mStorageId", "I");
	if (field_storageInfo_storageId == NULL) {
	ALOGE("Can't find MtpStorageInfo.mStorageId");
	return -1;
	}
	field_storageInfo_maxCapacity = env->GetFieldID(clazz, "mMaxCapacity", "J");
	if (field_storageInfo_maxCapacity == NULL) {
	ALOGE("Can't find MtpStorageInfo.mMaxCapacity");
	return -1;
	}
	field_storageInfo_freeSpace = env->GetFieldID(clazz, "mFreeSpace", "J");
	if (field_storageInfo_freeSpace == NULL) {
	ALOGE("Can't find MtpStorageInfo.mFreeSpace");
	return -1;
	}
	field_storageInfo_description = env->GetFieldID(clazz, "mDescription", "Ljava/lang/String;");
	if (field_storageInfo_description == NULL) {
	ALOGE("Can't find MtpStorageInfo.mDescription");
	return -1;
	}
	field_storageInfo_volumeIdentifier = env->GetFieldID(clazz, "mVolumeIdentifier", "Ljava/lang/String;");
	if (field_storageInfo_volumeIdentifier == NULL) {
	ALOGE("Can't find MtpStorageInfo.mVolumeIdentifier");
	return -1;
	}
	clazz_storageInfo = (jclass)env->NewGlobalRef(clazz);

	clazz = env->FindClass("android/mtp/MtpObjectInfo");
	if (clazz == NULL) {
	ALOGE("Can't find android/mtp/MtpObjectInfo");
	return -1;
	}
	constructor_objectInfo = env->GetMethodID(clazz, "<init>", "()V");
	if (constructor_objectInfo == NULL) {
	ALOGE("Can't find android/mtp/MtpObjectInfo constructor");
	return -1;
	}
	field_objectInfo_handle = env->GetFieldID(clazz, "mHandle", "I");
	if (field_objectInfo_handle == NULL) {
	ALOGE("Can't find MtpObjectInfo.mHandle");
	return -1;
	}
	field_objectInfo_storageId = env->GetFieldID(clazz, "mStorageId", "I");
	if (field_objectInfo_storageId == NULL) {
	ALOGE("Can't find MtpObjectInfo.mStorageId");
	return -1;
	}
	field_objectInfo_format = env->GetFieldID(clazz, "mFormat", "I");
	if (field_objectInfo_format == NULL) {
	ALOGE("Can't find MtpObjectInfo.mFormat");
	return -1;
	}
	field_objectInfo_protectionStatus = env->GetFieldID(clazz, "mProtectionStatus", "I");
	if (field_objectInfo_protectionStatus == NULL) {
	ALOGE("Can't find MtpObjectInfo.mProtectionStatus");
	return -1;
	}
	field_objectInfo_compressedSize = env->GetFieldID(clazz, "mCompressedSize", "I");
	if (field_objectInfo_compressedSize == NULL) {
	ALOGE("Can't find MtpObjectInfo.mCompressedSize");
	return -1;
	}
	field_objectInfo_thumbFormat = env->GetFieldID(clazz, "mThumbFormat", "I");
	if (field_objectInfo_thumbFormat == NULL) {
	ALOGE("Can't find MtpObjectInfo.mThumbFormat");
	return -1;
	}
	field_objectInfo_thumbCompressedSize = env->GetFieldID(clazz, "mThumbCompressedSize", "I");
	if (field_objectInfo_thumbCompressedSize == NULL) {
	ALOGE("Can't find MtpObjectInfo.mThumbCompressedSize");
	return -1;
	}
	field_objectInfo_thumbPixWidth = env->GetFieldID(clazz, "mThumbPixWidth", "I");
	if (field_objectInfo_thumbPixWidth == NULL) {
	ALOGE("Can't find MtpObjectInfo.mThumbPixWidth");
	return -1;
	}
	field_objectInfo_thumbPixHeight = env->GetFieldID(clazz, "mThumbPixHeight", "I");
	if (field_objectInfo_thumbPixHeight == NULL) {
	ALOGE("Can't find MtpObjectInfo.mThumbPixHeight");
	return -1;
	}
	field_objectInfo_imagePixWidth = env->GetFieldID(clazz, "mImagePixWidth", "I");
	if (field_objectInfo_imagePixWidth == NULL) {
	ALOGE("Can't find MtpObjectInfo.mImagePixWidth");
	return -1;
	}
	field_objectInfo_imagePixHeight = env->GetFieldID(clazz, "mImagePixHeight", "I");
	if (field_objectInfo_imagePixHeight == NULL) {
	ALOGE("Can't find MtpObjectInfo.mImagePixHeight");
	return -1;
	}
	field_objectInfo_imagePixDepth = env->GetFieldID(clazz, "mImagePixDepth", "I");
	if (field_objectInfo_imagePixDepth == NULL) {
	ALOGE("Can't find MtpObjectInfo.mImagePixDepth");
	return -1;
	}
	field_objectInfo_parent = env->GetFieldID(clazz, "mParent", "I");
	if (field_objectInfo_parent == NULL) {
	ALOGE("Can't find MtpObjectInfo.mParent");
	return -1;
	}
	field_objectInfo_associationType = env->GetFieldID(clazz, "mAssociationType", "I");
	if (field_objectInfo_associationType == NULL) {
	ALOGE("Can't find MtpObjectInfo.mAssociationType");
	return -1;
	}
	field_objectInfo_associationDesc = env->GetFieldID(clazz, "mAssociationDesc", "I");
	if (field_objectInfo_associationDesc == NULL) {
	ALOGE("Can't find MtpObjectInfo.mAssociationDesc");
	return -1;
	}
	field_objectInfo_sequenceNumber = env->GetFieldID(clazz, "mSequenceNumber", "I");
	if (field_objectInfo_sequenceNumber == NULL) {
	ALOGE("Can't find MtpObjectInfo.mSequenceNumber");
	return -1;
	}
	field_objectInfo_name = env->GetFieldID(clazz, "mName", "Ljava/lang/String;");
	if (field_objectInfo_name == NULL) {
	ALOGE("Can't find MtpObjectInfo.mName");
	return -1;
	}
	field_objectInfo_dateCreated = env->GetFieldID(clazz, "mDateCreated", "J");
	if (field_objectInfo_dateCreated == NULL) {
	ALOGE("Can't find MtpObjectInfo.mDateCreated");
	return -1;
	}
	field_objectInfo_dateModified = env->GetFieldID(clazz, "mDateModified", "J");
	if (field_objectInfo_dateModified == NULL) {
	ALOGE("Can't find MtpObjectInfo.mDateModified");
	return -1;
	}
	field_objectInfo_keywords = env->GetFieldID(clazz, "mKeywords", "Ljava/lang/String;");
	if (field_objectInfo_keywords == NULL) {
	ALOGE("Can't find MtpObjectInfo.mKeywords");
	return -1;
	}
	clazz_objectInfo = (jclass)env->NewGlobalRef(clazz);

	clazz = env->FindClass("android/mtp/MtpDevice");
	if (clazz == NULL) {
	ALOGE("Can't find android/mtp/MtpDevice");
	return -1;
	}
	field_context = env->GetFieldID(clazz, "mNativeContext", "J");
	if (field_context == NULL) {
	ALOGE("Can't find MtpDevice.mNativeContext");
	return -1;
	}

	return AndroidRuntime::registerNativeMethods(env,
	"android/mtp/MtpDevice", gMethods, NELEM(gMethods));
	}