core/jni/android_view_InputChannel.cpp

/*
 * 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_TAG "InputChannel-JNI"

#include <nativehelper/JNIHelp.h>

#include <android_runtime/AndroidRuntime.h>
#include <binder/Parcel.h>
#include <utils/Log.h>
#include <input/InputTransport.h>
#include "android_view_InputChannel.h"
#include "android_os_Parcel.h"
#include "android_util_Binder.h"

#include "core_jni_helpers.h"

namespace android {

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

static struct {
    jclass clazz;

    jfieldID mPtr;   // native object attached to the DVM InputChannel
    jmethodID ctor;
} gInputChannelClassInfo;

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

class NativeInputChannel {
public:
    explicit NativeInputChannel(const sp<InputChannel>& inputChannel);
    ~NativeInputChannel();

    inline sp<InputChannel> getInputChannel() { return mInputChannel; }

    void setDisposeCallback(InputChannelObjDisposeCallback callback, void* data);
    void invokeAndRemoveDisposeCallback(JNIEnv* env, jobject obj);

private:
    sp<InputChannel> mInputChannel;
    InputChannelObjDisposeCallback mDisposeCallback;
    void* mDisposeData;
};

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

NativeInputChannel::NativeInputChannel(const sp<InputChannel>& inputChannel) :
    mInputChannel(inputChannel), mDisposeCallback(NULL) {
}

NativeInputChannel::~NativeInputChannel() {
}

void NativeInputChannel::setDisposeCallback(InputChannelObjDisposeCallback callback, void* data) {
    mDisposeCallback = callback;
    mDisposeData = data;
}

void NativeInputChannel::invokeAndRemoveDisposeCallback(JNIEnv* env, jobject obj) {
    if (mDisposeCallback) {
        mDisposeCallback(env, obj, mInputChannel, mDisposeData);
        mDisposeCallback = NULL;
        mDisposeData = NULL;
    }
}

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

static NativeInputChannel* android_view_InputChannel_getNativeInputChannel(JNIEnv* env,
        jobject inputChannelObj) {
    jlong longPtr = env->GetLongField(inputChannelObj, gInputChannelClassInfo.mPtr);
    return reinterpret_cast<NativeInputChannel*>(longPtr);
}

static void android_view_InputChannel_setNativeInputChannel(JNIEnv* env, jobject inputChannelObj,
        NativeInputChannel* nativeInputChannel) {
    env->SetLongField(inputChannelObj, gInputChannelClassInfo.mPtr,
             reinterpret_cast<jlong>(nativeInputChannel));
}

sp<InputChannel> android_view_InputChannel_getInputChannel(JNIEnv* env, jobject inputChannelObj) {
    NativeInputChannel* nativeInputChannel =
            android_view_InputChannel_getNativeInputChannel(env, inputChannelObj);
    return nativeInputChannel != NULL ? nativeInputChannel->getInputChannel() : NULL;
}

void android_view_InputChannel_setDisposeCallback(JNIEnv* env, jobject inputChannelObj,
        InputChannelObjDisposeCallback callback, void* data) {
    NativeInputChannel* nativeInputChannel =
            android_view_InputChannel_getNativeInputChannel(env, inputChannelObj);
    if (nativeInputChannel == NULL) {
        ALOGW("Cannot set dispose callback because input channel object has not been initialized.");
    } else {
        nativeInputChannel->setDisposeCallback(callback, data);
    }
}

static jobject android_view_InputChannel_createInputChannel(JNIEnv* env,
        std::unique_ptr<NativeInputChannel> nativeInputChannel) {
    jobject inputChannelObj = env->NewObject(gInputChannelClassInfo.clazz,
            gInputChannelClassInfo.ctor);
    if (inputChannelObj) {
        android_view_InputChannel_setNativeInputChannel(env, inputChannelObj,
                 nativeInputChannel.release());
    }
    return inputChannelObj;
}

static jobjectArray android_view_InputChannel_nativeOpenInputChannelPair(JNIEnv* env,
        jclass clazz, jstring nameObj) {
    const char* nameChars = env->GetStringUTFChars(nameObj, NULL);
    std::string name = nameChars;
    env->ReleaseStringUTFChars(nameObj, nameChars);

    sp<InputChannel> serverChannel;
    sp<InputChannel> clientChannel;
    status_t result = InputChannel::openInputChannelPair(name, serverChannel, clientChannel);

    if (result) {
        String8 message;
        message.appendFormat("Could not open input channel pair.  status=%d", result);
        jniThrowRuntimeException(env, message.string());
        return NULL;
    }

    jobjectArray channelPair = env->NewObjectArray(2, gInputChannelClassInfo.clazz, NULL);
    if (env->ExceptionCheck()) {
        return NULL;
    }

    jobject serverChannelObj = android_view_InputChannel_createInputChannel(env,
            std::make_unique<NativeInputChannel>(serverChannel));
    if (env->ExceptionCheck()) {
        return NULL;
    }

    jobject clientChannelObj = android_view_InputChannel_createInputChannel(env,
            std::make_unique<NativeInputChannel>(clientChannel));
    if (env->ExceptionCheck()) {
        return NULL;
    }

    env->SetObjectArrayElement(channelPair, 0, serverChannelObj);
    env->SetObjectArrayElement(channelPair, 1, clientChannelObj);
    return channelPair;
}

static void android_view_InputChannel_nativeDispose(JNIEnv* env, jobject obj, jboolean finalized) {
    NativeInputChannel* nativeInputChannel =
            android_view_InputChannel_getNativeInputChannel(env, obj);
    if (nativeInputChannel) {
        if (finalized) {
            ALOGW("Input channel object '%s' was finalized without being disposed!",
                    nativeInputChannel->getInputChannel()->getName().c_str());
        }

        nativeInputChannel->invokeAndRemoveDisposeCallback(env, obj);

        android_view_InputChannel_setNativeInputChannel(env, obj, NULL);
        delete nativeInputChannel;
    }
}

static void android_view_InputChannel_nativeTransferTo(JNIEnv* env, jobject obj,
        jobject otherObj) {
    if (android_view_InputChannel_getNativeInputChannel(env, otherObj) != NULL) {
        jniThrowException(env, "java/lang/IllegalStateException",
                "Other object already has a native input channel.");
        return;
    }

    NativeInputChannel* nativeInputChannel =
            android_view_InputChannel_getNativeInputChannel(env, obj);
    android_view_InputChannel_setNativeInputChannel(env, otherObj, nativeInputChannel);
    android_view_InputChannel_setNativeInputChannel(env, obj, NULL);
}

static void android_view_InputChannel_nativeReadFromParcel(JNIEnv* env, jobject obj,
        jobject parcelObj) {
    if (android_view_InputChannel_getNativeInputChannel(env, obj) != NULL) {
        jniThrowException(env, "java/lang/IllegalStateException",
                "This object already has a native input channel.");
        return;
    }

    Parcel* parcel = parcelForJavaObject(env, parcelObj);
    if (parcel) {
        bool isInitialized = parcel->readInt32();
        if (isInitialized) {
            String8 name = parcel->readString8();
            int rawFd = parcel->readFileDescriptor();
            int dupFd = dup(rawFd);
            if (dupFd < 0) {
                ALOGE("Error %d dup channel fd %d.", errno, rawFd);
                jniThrowRuntimeException(env,
                        "Could not read input channel file descriptors from parcel.");
                return;
            }

            InputChannel* inputChannel = new InputChannel(name.string(), dupFd);
            NativeInputChannel* nativeInputChannel = new NativeInputChannel(inputChannel);

            android_view_InputChannel_setNativeInputChannel(env, obj, nativeInputChannel);
        }
    }
}

static void android_view_InputChannel_nativeWriteToParcel(JNIEnv* env, jobject obj,
        jobject parcelObj) {
    Parcel* parcel = parcelForJavaObject(env, parcelObj);
    if (parcel) {
        NativeInputChannel* nativeInputChannel =
                android_view_InputChannel_getNativeInputChannel(env, obj);
        if (nativeInputChannel) {
            sp<InputChannel> inputChannel = nativeInputChannel->getInputChannel();

            parcel->writeInt32(1);
            parcel->writeString8(String8(inputChannel->getName().c_str()));
            parcel->writeDupFileDescriptor(inputChannel->getFd());
        } else {
            parcel->writeInt32(0);
        }
    }
}

static jstring android_view_InputChannel_nativeGetName(JNIEnv* env, jobject obj) {
    NativeInputChannel* nativeInputChannel =
            android_view_InputChannel_getNativeInputChannel(env, obj);
    if (! nativeInputChannel) {
        return NULL;
    }

    jstring name = env->NewStringUTF(nativeInputChannel->getInputChannel()->getName().c_str());
    return name;
}

static void android_view_InputChannel_nativeDup(JNIEnv* env, jobject obj, jobject otherObj) {
    NativeInputChannel* nativeInputChannel =
            android_view_InputChannel_getNativeInputChannel(env, obj);
    if (nativeInputChannel) {
        android_view_InputChannel_setNativeInputChannel(env, otherObj,
                new NativeInputChannel(nativeInputChannel->getInputChannel()->dup()));
    }
}

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

static const JNINativeMethod gInputChannelMethods[] = {
    /* name, signature, funcPtr */
    { "nativeOpenInputChannelPair", "(Ljava/lang/String;)[Landroid/view/InputChannel;",
            (void*)android_view_InputChannel_nativeOpenInputChannelPair },
    { "nativeDispose", "(Z)V",
            (void*)android_view_InputChannel_nativeDispose },
    { "nativeTransferTo", "(Landroid/view/InputChannel;)V",
            (void*)android_view_InputChannel_nativeTransferTo },
    { "nativeReadFromParcel", "(Landroid/os/Parcel;)V",
            (void*)android_view_InputChannel_nativeReadFromParcel },
    { "nativeWriteToParcel", "(Landroid/os/Parcel;)V",
            (void*)android_view_InputChannel_nativeWriteToParcel },
    { "nativeGetName", "()Ljava/lang/String;",
            (void*)android_view_InputChannel_nativeGetName },
    { "nativeDup", "(Landroid/view/InputChannel;)V",
            (void*)android_view_InputChannel_nativeDup },
};

int register_android_view_InputChannel(JNIEnv* env) {
    int res = RegisterMethodsOrDie(env, "android/view/InputChannel", gInputChannelMethods,
                                   NELEM(gInputChannelMethods));

    jclass clazz = FindClassOrDie(env, "android/view/InputChannel");
    gInputChannelClassInfo.clazz = MakeGlobalRefOrDie(env, clazz);

    gInputChannelClassInfo.mPtr = GetFieldIDOrDie(env, gInputChannelClassInfo.clazz, "mPtr", "J");

    gInputChannelClassInfo.ctor = GetMethodIDOrDie(env, gInputChannelClassInfo.clazz, "<init>",
                                                   "()V");

    return res;
}

} // namespace android