Radixor/gradle/lucene-benchmarks.gradle

import org.gradle.plugins.ide.eclipse.model.SourceFolder


def luceneVersion = '10.5.0'
def luceneRootRelativePath = 'third-party/lucene'
def luceneSourceArtifacts = ['lucene-analysis-common', 'lucene-analyzers-common']
def luceneSourceDirectory = layout.buildDirectory.dir("${luceneRootRelativePath}/source/analyzers-common")

def luceneGeneratedSourceDirectory = layout.buildDirectory.dir('generated/sources/lucene')
def luceneGeneratedPorterFile = luceneGeneratedSourceDirectory.map { it.file('org/egothor/stemmer/benchmark/LucenePorterStemmerCopied.java') }

def luceneSourceDownloadFile = layout.buildDirectory.file("${luceneRootRelativePath}/lucene-${luceneVersion}-sources.jar")

dependencies {
    jmhImplementation "org.apache.lucene:lucene-analysis-common:${luceneVersion}"
    jmhImplementation "org.apache.lucene:lucene-analysis-stempel:${luceneVersion}"
    jmhImplementation "org.apache.lucene:lucene-analysis-morfologik:${luceneVersion}"
}

def buildLuceneSourcesName = { final String artifact ->
    "${artifact}-${luceneVersion}-sources.jar"
}
def buildLuceneSourcesUrl = { final String artifact ->
    "https://repo1.maven.org/maven2/org/apache/lucene/${artifact}/${luceneVersion}/${buildLuceneSourcesName(artifact)}"
}

def isLuceneSourcesDownloadable = { final String artifact ->
    try {
        final URL sourceUrl = new URL(buildLuceneSourcesUrl(artifact))
        final java.net.HttpURLConnection connection = (java.net.HttpURLConnection) sourceUrl.openConnection()
        connection.requestMethod = 'HEAD'
        connection.instanceFollowRedirects = true
        connection.connectTimeout = 10000
        connection.readTimeout = 10000
        final int responseCode = connection.responseCode
        connection.disconnect()
        return responseCode == 200
    } catch (Exception ignored) {
        return false
    }
}

def downloadLuceneSourcesJar = { ->
    final File targetFile = luceneSourceDownloadFile.get().asFile

    for (String artifact : luceneSourceArtifacts) {
        if (!isLuceneSourcesDownloadable(artifact)) {
            continue
        }

        final String sourceUrl = buildLuceneSourcesUrl(artifact)
        final File tempFile = new File(targetFile.parentFile, "${artifact}.${luceneVersion}.tmp")
        try {
            new URL(sourceUrl).withInputStream { inputStream ->
                tempFile.parentFile.mkdirs()
                tempFile.withOutputStream { outputStream ->
                    outputStream << inputStream
                }
            }
            if (!tempFile.exists() || tempFile.length() <= 0L) {
                throw new GradleException("Downloaded Lucene source artifact for ${artifact} was empty.")
            }
            targetFile.delete()
            if (!tempFile.renameTo(targetFile)) {
                throw new GradleException("Failed to persist downloaded Lucene source artifact for ${artifact}.")
            }
            return
        } catch (Exception ignored) {
            tempFile.delete()
        }
    }

    throw new GradleException(
            "Failed to download Apache Lucene source artifacts ${luceneSourceArtifacts} for version ${luceneVersion}.")
}

def luceneSourceClasspathPath = provider {
    project.relativePath(luceneGeneratedSourceDirectory.get().asFile)
}
def luceneEclipseClasspathAttributes = [
        gradle_scope        : 'jmh',
        gradle_used_by_scope: 'jmh',
        test                : 'true'
]

def isAbsoluteClasspathPath = { String path ->
    path.startsWith('/') || path ==~ /^[A-Za-z]:[\\\/].*/
}

def luceneGeneratedPorterNotice = '''
/**
 * Generated at benchmark execution time from Apache Lucene source.
 *
 * This source copy is compiled only for the JMH benchmark source set and is
 * not committed as production code.
 */
'''

def transformPorterStemmerSource = { final File sourceFile, final File targetFile ->
    if (!sourceFile.exists()) {
        throw new GradleException("Apache Lucene PorterStemmer source was not available at ${sourceFile}.")
    }

    final String sourceText = sourceFile.getText('UTF-8')
    String transformedText = sourceText

    if (transformedText.contains('package org.apache.lucene.analysis.en;')) {
        transformedText = transformedText.replaceFirst(/(?m)^\s*package\s+org\.apache\.lucene\.analysis\.en\s*;/,
                'package org.egothor.stemmer.benchmark;')
    } else {
        throw new GradleException(
                'Expected Lucene package-private PorterStemmer in org.apache.lucene.analysis.en package was not found in downloaded source.')
    }

    transformedText = transformedText.replaceFirst(/(?m)^\s*class\s+PorterStemmer\s*\{/, 'public final class LucenePorterStemmerCopied {')
    transformedText = transformedText.replaceFirst(/(?m)^\s*public\s+PorterStemmer\(\)/, 'public LucenePorterStemmerCopied()')

    if (!transformedText.contains('class LucenePorterStemmerCopied')) {
        throw new GradleException("Failed to rename PorterStemmer class when generating ${targetFile}.")
    }

    targetFile.parentFile.mkdirs()
    targetFile.text = transformedText
}

def resolveLucenePorterStemmerSource = { ->
    final File sourceRoot = luceneSourceDirectory.get().asFile
    final List<String> candidates = [
            'org/apache/lucene/analysis/en/org/apache/lucene/analysis/en/PorterStemmer.java',
            'org/apache/lucene/analysis/en/PorterStemmer.java',
            'org/apache/lucene/analysis/en/org/tartarus/snowball/ext/PorterStemmer.java'
    ]

    for (String candidate : candidates) {
        final File file = new File(sourceRoot, candidate)
        if (file.exists()) {
            return file
        }
    }

    final FileTree porterCandidates = fileTree(sourceRoot).matching { include '**/PorterStemmer.java' }
    for (File file : porterCandidates.files) {
        if (file.text.contains('class PorterStemmer') && file.text.contains('package org.apache.lucene.analysis.en;')) {
            return file
        }
    }

    throw new GradleException('Unable to resolve Lucene PorterStemmer source file from extracted artifact.')
}

tasks.register('downloadLuceneAnalyzersSources') {
    group = 'build setup'
    description = 'Downloads Apache Lucene analysis sources for benchmark-only code generation.'

    outputs.file(luceneSourceDownloadFile)

    doLast {
        if (!luceneSourceDownloadFile.get().asFile.exists()) {
            downloadLuceneSourcesJar()
        }
    }
}

tasks.register('extractLuceneAnalyzersSources', Copy) {
    group = 'build setup'
    description = 'Extracts Apache Lucene analysis source JAR for benchmark-only extraction.'

    dependsOn(tasks.named('downloadLuceneAnalyzersSources'))

    from(zipTree(luceneSourceDownloadFile))
    into(luceneSourceDirectory)
}

tasks.register('generateLucenePorterStemmerCopied') {
    group = 'build setup'
    description = 'Generates LucenePorterStemmerCopied into the build-only benchmark source directory.'

    dependsOn(tasks.named('extractLuceneAnalyzersSources'))

    inputs.dir(luceneSourceDirectory)
    outputs.file(luceneGeneratedPorterFile)

    doLast {
        final File sourceFile = resolveLucenePorterStemmerSource()
        transformPorterStemmerSource(sourceFile, luceneGeneratedPorterFile.get().asFile)
    }
}

sourceSets {
    jmh {
        java {
            srcDir(luceneGeneratedSourceDirectory)
        }
    }
}

tasks.named('compileJmhJava') {
    dependsOn(tasks.named('generateLucenePorterStemmerCopied'))
}

eclipse {
    classpath {
        file {
            whenMerged { classpath ->
                String generatedPath = luceneSourceClasspathPath.get()

                classpath.entries.removeAll { entry ->
                    entry.hasProperty('path') && (
                            entry.path == generatedPath ||
                            isAbsoluteClasspathPath(entry.path)
                    )
                }

                SourceFolder luceneEntry = new SourceFolder(generatedPath, null)
                luceneEntry.output = 'bin/jmh'
                luceneEclipseClasspathAttributes.each { String name, String value ->
                    luceneEntry.entryAttributes[name] = value
                }
                classpath.entries.add(luceneEntry)
            }
        }
    }
}