org.web3j.evm.PassthroughTracer.kt Maven / Gradle / Ivy

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/*
 * Copyright 2019 Web3 Labs Ltd.
 *
 * 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.
 */
package org.web3j.evm

import org.hyperledger.besu.evm.EVM
import org.hyperledger.besu.evm.frame.MessageFrame
import org.hyperledger.besu.evm.operation.Operation
import org.web3j.evm.utils.NullReader
import java.io.BufferedReader
import java.io.File
import java.lang.StringBuilder

data class PassthroughTracerContext(val source: String = "", val filePath: String? = null, val firstSelectedLine: Int? = null, val firstSelectedOffset: Int? = null)

class PassthroughTracer(metaFile: File? = File("build/resources/main/solidity")) : ConsoleDebugTracer(
    metaFile,
    BufferedReader(
        NullReader(),
    ),
) {
    private var passthroughTracerContext: PassthroughTracerContext = PassthroughTracerContext()

    fun lastContext() = passthroughTracerContext

    fun resetContext() {
        passthroughTracerContext = PassthroughTracerContext()
    }

    @Throws(ExceptionalHaltException::class)
    fun traceExecution(
        messageFrame: MessageFrame,
        evm: EVM,
        executeOperation: Operation,
    ) {
        if (metaFile != null && metaFile.exists()) {
            val (sourceMapElement, sourceFile) = sourceAtMessageFrame(messageFrame)
            val (filePath, sourceSection) = sourceFile

            val sb = StringBuilder()

            if (sourceMapElement != null) {
                sb.append("At solidity source location ${sourceMapElement.sourceFileByteOffset}:${sourceMapElement.lengthOfSourceRange}:${sourceMapElement.sourceIndex}:")
            } else sb.append("At unknown solidity source location:")

            sb.append('\n')
            sb.append('\n')

            val trimmedSourceSection = mergeSourceContent(sourceSection)
                .dropWhile { it.isBlank() }
                .reversed()
                .dropWhile { it.isBlank() }
                .reversed()

            passthroughTracerContext = if (trimmedSourceSection.isEmpty()) {
                PassthroughTracerContext()
            } else {
                val source = sb.append(trimmedSourceSection.joinToString("\n")).toString()
                val firstSelectedLine = sourceSection.entries.filter { it.value.selected }.map { it.key }.minOrNull()
                val firstSelectedOffset = sourceSection[firstSelectedLine]?.offset

                PassthroughTracerContext(source, filePath, firstSelectedLine, firstSelectedOffset)
            }
        }

        executeOperation.execute(messageFrame, evm)
    }
}