BaseDoKitAsmTransformer.kt

package com.didichuxing.doraemonkit.plugin.asmtransformer

import com.didichuxing.doraemonkit.plugin.asmclasstransformer.BaseDoKitClassTransformer
import com.didiglobal.booster.annotations.Priority
import com.didiglobal.booster.transform.TransformContext
import com.didiglobal.booster.transform.Transformer
import org.objectweb.asm.ClassReader
import org.objectweb.asm.ClassWriter
import org.objectweb.asm.tree.ClassNode
import java.lang.management.ManagementFactory
import java.lang.management.ThreadMXBean

/**
 * ================================================
 * 作    者：jint（金台）
 * 版    本：1.0
 * 创建日期：2020/5/21-16:44
 * 描    述：
 * 修订历史：
 * ================================================
 */
open class BaseDoKitAsmTransformer : Transformer {
    private val threadMxBean = ManagementFactory.getThreadMXBean()

    private val durations = mutableMapOf<BaseDoKitClassTransformer, Long>()

    internal val transformers: Collection<BaseDoKitClassTransformer>

    /**
     * For unit test only
     */
    constructor(vararg transformers: BaseDoKitClassTransformer) {
        this.transformers = transformers.sortedBy {
            it.javaClass.getAnnotation(Priority::class.java)?.value ?: 0
        }
    }

    override fun onPreTransform(context: TransformContext) {
        this.transformers.forEach { transformer ->
            this.threadMxBean.sumCpuTime(transformer) {
                transformer.onPreTransform(context)
            }
        }
    }

    override fun transform(context: TransformContext, bytecode: ByteArray): ByteArray {
        return ClassWriter(ClassWriter.COMPUTE_MAXS).also { writer ->
            this.transformers.fold(ClassNode().also { klass ->
                ClassReader(bytecode).accept(klass, 0)
            }) { klass, transformer ->
                this.threadMxBean.sumCpuTime(transformer) {
                    transformer.transform(context, klass)
                }
            }.accept(writer)
        }.toByteArray()
    }

    override fun onPostTransform(context: TransformContext) {
        this.transformers.forEach { transformer ->
            this.threadMxBean.sumCpuTime(transformer) {
                transformer.onPostTransform(context)
            }
        }

        val w1 = this.durations.keys.map {
            it.javaClass.name.length
        }.max() ?: 20
        this.durations.forEach { (transformer, ns) ->
            println("${transformer.javaClass.name.padEnd(w1 + 1)}: ${ns / 1000000} ms")
        }
    }

    private fun <R> ThreadMXBean.sumCpuTime(transformer: BaseDoKitClassTransformer, action: () -> R): R {
        val ct0 = this.currentThreadCpuTime
        val result = action()
        val ct1 = this.currentThreadCpuTime
        durations[transformer] = durations.getOrDefault(transformer, 0) + (ct1 - ct0)
        return result
    }

}