NullPointerException: Attempt to invoke virtual method 'java.nio.Buffer java.nio.ByteBuffer.rewind()' on a null object reference

[panpf]

Issue Info

Info	Value
Device Info	arm64 模拟器
System Version	api 21
APNG4Android Library Version	3.0.1

Issue Description and Steps

我尝试将 awebp 模块集成到我的项目中，用于在 api 28 以下解码 webp 的第一帧，代码如下：

override fun decode(): DecodeResult {
    val streamLoader = dataSource.toStreamLoader(requestContext.request.context)
    val webpDecoder = WebPDecoder(streamLoader, null)
    val bounds = webpDecoder.bounds
    val imageInfo = ImageInfo(
        width = bounds.width(),
        height = bounds.height(),
        mimeType = "image/webp"
    )
    val resize = requestContext.computeResize(imageInfo.size)
    val inSampleSize = calculateSampleSize(
        imageSize = imageInfo.size,
        targetSize = resize.size,
        smallerSizeMode = resize.precision.isSmallerSizeMode()
    )
    val dstSize = Size(
        width = ceil(imageInfo.width / inSampleSize.toFloat()).toInt(),
        height = ceil(imageInfo.height / inSampleSize.toFloat()).toInt()
    )
    webpDecoder.setDesiredSize(dstSize.width, dstSize.height)
    val bitmap = webpDecoder.getFrameBitmap(0)
    val decodeResult = DecodeResult(
        image = bitmap.asImage(),
        imageInfo = imageInfo,
        dataFrom = dataSource.dataFrom,
        resize = resize,
        transformeds = null,
        extras = null,
    )
    val resizeResult = decodeResult.resize(resize)
    return resizeResult
}

fun DataSource.toStreamLoader(context: Context): Loader {
    return when (this) {
        is FileDataSource -> {
            FileLoader(path.toString())
        }

        is ByteArrayDataSource -> {
            object : ByteBufferLoader() {
                override fun getByteBuffer(): ByteBuffer {
                    return ByteBuffer.wrap(data)
                }
            }
        }

        is ContentDataSource -> {
            object : StreamLoader() {
                override fun getInputStream(): InputStream {
                    return context.contentResolver.openInputStream(contentUri)
                        ?: throw IOException("Invalid content uri: $contentUri")
                }
            }
        }

        is AssetDataSource -> {
            AssetStreamLoader(context, fileName)
        }

        is ResourceDataSource -> {
            ResourceStreamLoader(context, resId)
        }

        else -> {
            throw IllegalArgumentException("Unsupported DataSource: ${this::class}")
        }
    }
}

上述代码抛出以下错误：

java.lang.NullPointerException: Attempt to invoke virtual method 'java.nio.Buffer java.nio.ByteBuffer.rewind()' on a null object reference
	at com.github.penfeizhou.animation.webp.decode.WebPDecoder.renderFrame(WebPDecoder.java:131)
	at com.github.penfeizhou.animation.decode.FrameSeqDecoder.step(FrameSeqDecoder.java:510)
	at com.github.penfeizhou.animation.decode.FrameSeqDecoder.getFrameBitmap(FrameSeqDecoder.java:552)
	at com.github.panpf.sketch.sample.util.PenfeiZhouAnimatedWebpFirstFrameDecoder.decode(PenfeiZhouAnimatedWebpFirstFrameDecoder.kt:73)
	at com.github.panpf.sketch.decode.internal.EngineDecodeInterceptor.intercept-gIAlu-s(EngineDecodeInterceptor.kt:45)
	at com.github.panpf.sketch.decode.internal.DecodeInterceptorChain.proceed-IoAF18A(DecodeInterceptorChain.kt:48)
	at com.github.panpf.sketch.sample.image.PaletteDecodeInterceptor.intercept-gIAlu-s(PaletteDecodeInterceptor.kt:17)
	at com.github.panpf.sketch.decode.internal.DecodeInterceptorChain.proceed-IoAF18A(DecodeInterceptorChain.kt:48)
	at com.github.panpf.sketch.transform.internal.TransformationDecodeInterceptor.intercept-gIAlu-s(TransformationDecodeInterceptor.kt:38)
	at com.github.panpf.sketch.decode.internal.DecodeInterceptorChain.proceed-IoAF18A(DecodeInterceptorChain.kt:48)
	at com.github.panpf.sketch.cache.internal.ResultCacheDecodeInterceptor.intercept-gIAlu-s(ResultCacheDecodeInterceptor.kt:72)
	at com.github.panpf.sketch.decode.internal.DecodeInterceptorChain.proceed-IoAF18A(DecodeInterceptorChain.kt:48)
	at com.github.panpf.sketch.request.PauseLoadWhenScrollingDecodeInterceptor.intercept-gIAlu-s(PauseLoadWhenScrollingDecodeInterceptor.kt:68)
	at com.github.panpf.sketch.decode.internal.DecodeInterceptorChain.proceed-IoAF18A(DecodeInterceptorChain.kt:48)
	at com.github.panpf.sketch.request.internal.EngineRequestInterceptor$intercept$decodeResult$1.invokeSuspend(EngineRequestInterceptor.kt:47)
	at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:33)
	at kotlinx.coroutines.DispatchedTask.run(DispatchedTask.kt:101)
	at kotlinx.coroutines.internal.LimitedDispatcher$Worker.run(LimitedDispatcher.kt:113)
	at kotlinx.coroutines.scheduling.TaskImpl.run(Tasks.kt:89)
	at kotlinx.coroutines.scheduling.CoroutineScheduler.runSafely(CoroutineScheduler.kt:589)
	at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.executeTask(CoroutineScheduler.kt:823)
	at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.runWorker(CoroutineScheduler.kt:720)
	at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.run(CoroutineScheduler.kt:707)

测试发现注释掉 webpDecoder.setDesiredSize(dstSize.width, dstSize.height) 这行就不会抛异常