override fun run() {        //搜索满足AAPT2 container format ：        //magic = 0x54504141 && version > 0 && count > 0 && type = RES_FILEval resources = sources().parallelStream().map {it to it.metadata}.collect(Collectors.toSet())resources.filter {            //过滤情况 ResourcesInternal.CompileFile = null的情况it.second != null}.groupBy({            //根据资源名分组it.second!!.resourceName.substringBeforeLast('/')}, {it.first to it.second}).forEach { entry ->//根据资源名分组            entry.value.groupBy({it.second!!.resourceName.substringAfterLast('/')}, {it.first to it.second!!}).map { group ->//组内根据density降序排序，再排除最高density的资源                group.value.sortedByDescending {it.second.config.density}.takeLast(group.value.size - 1)}.flatten().parallelStream().forEach {try {　　　　　　　　　　　　//对除最高density的其他density资源文件进行删除if (it.first.delete()) {val original = File(it.second.sourcePath)results.add(CompressionResult(it.first, original.length(), 0, original))} else {logger.error("Cannot delete file `${it.first}`")}} catch (e: IOException) {logger.error("Cannot delete file `${it.first}`", e)}}}}}

 /*** Select the best compressor*/fun get(project: Project): CompressionTool? {val pngquant = project.findProperty(PROPERTY_PNGQUANT)?.toString()val compressor = project.findProperty(PROPERTY_COMPRESSOR)?.toString()val binDir = project.buildDir.file(SdkConstants.FD_OUTPUT).absolutePathval minSdkVersion = project.getAndroid<BaseExtension>().defaultConfig.minSdkVersion.apiLevelproject.logger.info("minSdkVersion: $minSdkVersion$")project.logger.info("$PROPERTY_COMPRESSOR: $compressor")project.logger.info("$PROPERTY_PNGQUANT: $pngquant")return when (compressor) {Cwebp.PROGRAM -> Cwebp(binDir)Pngquant.PROGRAM -> Pngquant(pngquant)else -> when {minSdkVersion >= 18 -> Cwebp(binDir)minSdkVersion in 15..17 -> Cwebp(binDir, true)else -> Pngquant(pngquant).let {if (it.isInstalled) it else null}}}}

//Cweboverride fun newCompressionTaskCreator() = SimpleCompressionTaskCreator(this) { aapt2 ->when (aapt2) {true -> when (opaque) {true -> CwebpCompressOpaqueFlatImages::classelse -> CwebpCompressFlatImages::class}else -> when (opaque) {true -> CwebpCompressOpaqueImages::classelse -> CwebpCompressImages::class}}
}//pngquant
override fun newCompressionTaskCreator() = SimpleCompressionTaskCreator(this) { aapt2 ->if (aapt2) PngquantCompressFlatImages::class else PngquantCompressImages::class}

//PngquantCompressFlatImages
override fun run() {...sources().parallelStream().map {it to it.metadata}.filter {it.second != null}.map {val output = compressedRes.file("${it.second!!.resourcePath.substringBeforeLast('.')}$DOT_PNG") Aapt2ActionData(it.first, it.second!!, output,listOf(pngquant, "--strip", "--skip-if-larger", "-f", "-o", output.absolutePath, "-s", "1", it.second!!.sourcePath),listOf(aapt2, "compile", "-o", it.first.parent, output.absolutePath))}.forEach {it.output.parentFile.mkdirs()val s0 = File(it.metadata.sourcePath).length()val rc = project.exec { spec ->spec.isIgnoreExitValue = truespec.commandLine = it.cmdline}...}}

//CwebpCompressFlatImages

override fun compress(filter: (File) -> Boolean) {  　　...

    sources().parallelStream().map {        it to it.metadata    }.filter {　　　　　　//在android15 - 17 还不支持透明的webp，过滤掉应用图标        it.second != null && isNotLauncherIcon(it.first, it.second!!) && filter(File(it.second!!.sourcePath))    }.map {        val output = compressedRes.file("${it.second!!.resourcePath.substringBeforeLast('.')}.webp")Aapt2ActionData(it.first, it.second!!, output,                listOf(cwebp, "-mt", "-quiet", "-q", "80", it.second!!.sourcePath, "-o", output.absolutePath),                listOf(aapt2, "compile", "-o", it.first.parent, output.absolutePath))    }.forEach {        it.output.parentFile.mkdirs()        val s0 = File(it.metadata.sourcePath).length()　　　　 //cwep压缩        val rc = project.exec { spec ->            spec.isIgnoreExitValue = true            spec.commandLine = it.cmdline        }        when (rc.exitValue) {            0 -> {                val s1 = it.output.length() if (s1 > s0) {　　　　　　　　　　　　//cwebp压缩后的产物文件大小比原图片还大，则使用原图                    results.add(CompressionResult(it.input, s0, s0, File(it.metadata.sourcePath),Compression))                    it.output.delete()                } else {                   ...                }            }           ...        }    }}

/********************aapt Package.cpp****************************//* these formats are already compressed, or don't compress well */
static const char* kNoCompressExt[] = {".jpg", ".jpeg", ".png", ".gif",".wav", ".mp2", ".mp3", ".ogg", ".aac",".mpg", ".mpeg", ".mid", ".midi", ".smf", ".jet",".rtttl", ".imy", ".xmf", ".mp4", ".m4a",".m4v", ".3gp", ".3gpp", ".3g2", ".3gpp2",".amr", ".awb", ".wma", ".wmv", ".webm", ".mkv"
};

/********************aapt2 Link.cpp****************************/

// Populate some default no-compress extensions that are already compressed.
options.extensions_to_not_compress.insert(
{".jpg", ".jpeg", ".png", ".gif", ".wav", ".mp2", ".mp3", ".ogg",
".aac", ".mpg", ".mpeg", ".mid", ".midi", ".smf", ".jet", ".rtttl",
".imy", ".xmf", ".mp4", ".m4a", ".m4v", ".3gp", ".3gpp", ".3g2",
".3gpp2", ".amr", ".awb", ".wma", ".wmv", ".webm", ".mkv"});

//同aapt源码的no-compress格式同出一辙

private val NO_COMPRESS = setOf(        "jpg", "jpeg", "png", "gif",        "wav", "mp2", "mp3", "ogg", "aac",        "mpg", "mpeg", "mid", "midi", "smf", "jet",        "rtttl", "imy", "xmf", "mp4", "m4a",        "m4v", "3gp", "3gpp", "3g2", "3gpp2",        "amr", "awb", "wma", "wmv", "webm", "mkv")

private fun BaseVariant.compressProcessedRes(results: CompressionResults) {    //搜索resources-*.ap_文件val files = scope.processedRes.search {it.name.startsWith(SdkConstants.FN_RES_BASE) && it.extension == SdkConstants.EXT_RES}files.parallelStream().forEach { ap_ ->val s0 = ap_.length()ap_.repack {            //过滤掉 不压缩存储的图片格式!NO_COMPRESS.contains(it.name.substringAfterLast('.'))}val s1 = ap_.length()results.add(CompressionResult(ap_, s0, s1, ap_))}
}private fun File.repack(shouldCompress: (ZipEntry) -> Boolean) {val dest = File.createTempFile(SdkConstants.FN_RES_BASE + SdkConstants.RES_QUALIFIER_SEP, SdkConstants.DOT_RES)ZipOutputStream(dest.outputStream()).use { output ->ZipFile(this).use { zip ->zip.entries().asSequence().forEach { origin ->val target = ZipEntry(origin.name).apply {size = origin.sizecrc = origin.crccomment = origin.commentextra = origin.extra                    //不压缩的格式，保持原有的ZipEntry.method,显然webp格式的图片的methodmethod = if (shouldCompress(origin)) ZipEntry.DEFLATED else origin.method}output.putNextEntry(target)zip.getInputStream(origin).use {it.copyTo(output)}output.closeEntry()}}}if (this.delete()) {if (!dest.renameTo(this)) {dest.copyTo(this, true)}}
}

variant.processResTask?.doLast{variant.removeRepeatResources(it.logger,results)
}

private fun File.findDuplicatedResources():Map<Key,ArrayList<DuplicatedOrUnusedEntry>>{var duplicatedResources = HashMap<Key,ArrayList<DuplicatedOrUnusedEntry>>(100)ZipFile(this).use { zip ->zip.entries().asSequence().forEach { entry ->val lastIndex : Int = entry.name.lastIndexOf('/')val key = Key(entry.crc.toString(),if(lastIndex == -1) "/" else entry.name.substring(0,lastIndex))if(!duplicatedResources.containsKey(key)){val list : ArrayList<DuplicatedOrUnusedEntry> = ArrayList(20)duplicatedResources[key] = list}val list = duplicatedResources[key]list?.add(DuplicatedOrUnusedEntry(entry.name,entry.size,entry.compressedSize,DuplicatedOrUnusedEntryType.duplicated))}}duplicatedResources.filter {it.value.size >= 2}.apply{duplicatedResources = this as HashMap<Key, ArrayList<DuplicatedOrUnusedEntry>>}return duplicatedResources
}

/*** Whether we should create small/empty dummy files instead of actually* removing file resources. This is to work around crashes on some devices* where the device is traversing resources. See http://b.android.com/79325 for more.*/

    // A 1x1 pixel PNG of type BufferedImage.TYPE_BYTE_GRAYpublic static final long TINY_PNG_CRC = 0x88b2a3b0L;// A 3x3 pixel PNG of type BufferedImage.TYPE_INT_ARGB with 9-patch markerspublic static final long TINY_9PNG_CRC = 0x1148f987L;// The XML document <x/> as binary-packed with AAPTpublic static final long TINY_XML_CRC = 0xd7e65643L;// The XML document <x/> as a proto packed with AAPT2public static final long TINY_PROTO_XML_CRC = 3204905971L;

private void replaceWithDummyEntry(JarOutputStream zos, ZipEntry entry, String name)throws IOException {// Create a new entry so that the compressed len is recomputed.byte[] bytes;long crc;if (name.endsWith(DOT_9PNG)) {bytes = TINY_9PNG;crc = TINY_9PNG_CRC;} else if (name.endsWith(DOT_PNG)) {bytes = TINY_PNG;crc = TINY_PNG_CRC;} else if (name.endsWith(DOT_XML)) {switch (format) {case BINARY:bytes = TINY_BINARY_XML;crc = TINY_BINARY_XML_CRC;break;case PROTO:bytes = TINY_PROTO_XML;crc = TINY_PROTO_XML_CRC;break;default:throw new IllegalStateException("");}} else {//没有预定资源格式，crc =0,数据为空bytes = new byte[0];crc = 0L;}JarEntry outEntry = new JarEntry(name);if (entry.getTime() != -1L) {outEntry.setTime(entry.getTime());}if (entry.getMethod() == JarEntry.STORED) {outEntry.setMethod(JarEntry.STORED);outEntry.setSize(bytes.length);outEntry.setCrc(crc);}zos.putNextEntry(outEntry);zos.write(bytes);zos.closeEntry();...
}

val unusedResourceCrcs  = longArrayOf(ResourceUsageAnalyzer.TINY_PNG_CRC,ResourceUsageAnalyzer.TINY_9PNG_CRC,ResourceUsageAnalyzer.TINY_BINARY_XML_CRC,ResourceUsageAnalyzer.TINY_PROTO_XML_CRC,0 //jpg、jpeg、webp等
)