Move download logic to task and remove build service

plugin/src/main/kotlin/de/infolektuell/gradle/jextract/GradleJextractPlugin.kt

@@ -14,7 +14,6 @@ import org.gradle.jvm.toolchain.JavaLanguageVersion
 
 abstract class GradleJextractPlugin : Plugin<Project> {
     override fun apply(project: Project) {
-        val serviceProvider = project.gradle.sharedServices.registerIfAbsent("${project.name}_${DownloadClient.SERVICE_NAME}", DownloadClient::class.java)
         val extension = project.extensions.create(JextractExtension.EXTENSION_NAME, JextractExtension::class.java)
         extension.generator.javaLanguageVersion.convention(JavaLanguageVersion.of(Jvm.current().javaVersionMajor ?: 22))
         project.extensions.findByType(JavaPluginExtension::class.java)?.let { extension.generator.javaLanguageVersion.convention(it.toolchain.languageVersion) }
@@ -26,8 +25,6 @@ abstract class GradleJextractPlugin : Plugin<Project> {
         val userOutput = project.layout.projectDirectory.dir(project.gradle.gradleUserHomeDir.absolutePath)
         val downloadTask = project.tasks.register("downloadJextract", DownloadTask::class.java) { task ->
             task.description = "Downloads Jextract"
-            task.downloadClient.convention(serviceProvider)
-            task.usesService(serviceProvider)
             task.resource.convention(resourceProvider)
             task.target.convention(userOutput.dir("downloads").file(task.resource.map { it.fileName }))
         }

plugin/src/main/kotlin/de/infolektuell/gradle/jextract/tasks/DownloadTask.kt

@@ -2,25 +2,71 @@ package de.infolektuell.gradle.jextract.tasks
 
 import de.infolektuell.gradle.jextract.extensions.JextractResolver
 import org.gradle.api.DefaultTask
+import org.gradle.api.GradleException
 import org.gradle.api.file.RegularFileProperty
 import org.gradle.api.provider.Property
 import org.gradle.api.tasks.*
+import java.io.InputStream
+import java.net.URI
+import java.net.http.HttpClient
+import java.net.http.HttpRequest
+import java.net.http.HttpResponse
 import java.nio.file.Files
+import java.nio.file.Path
+import java.nio.file.StandardCopyOption
+import java.security.DigestInputStream
+import java.security.MessageDigest
+import java.time.Duration
 
 abstract class DownloadTask : DefaultTask() {
-    @get:Internal
-    abstract val downloadClient: Property<DownloadClient>
     @get:Input
     abstract val resource: Property<JextractResolver.Resource>
     @get:OutputFile
     abstract val target: RegularFileProperty
+    private val client: HttpClient = HttpClient.newBuilder().connectTimeout(Duration.ofSeconds(10)).version(HttpClient.Version.HTTP_1_1).build()
 
     @TaskAction
     fun download() {
-        Files.createDirectories(target.asFile.get().parentFile.toPath())
         val url = resource.get().url
         val checksum = resource.get().checksum
         val algorithm = resource.get().algorithm
-        downloadClient.get().download(url, checksum, algorithm, target.get())
+        val targetPath = target.get().asFile.toPath()
+        Files.createDirectories(targetPath.parent)
+        download(url, checksum, algorithm, targetPath)
+    }
+
+    private fun download(source: URI, checksum: String, algorithm: String, target: Path) {
+        val downloaded = verify(target, checksum, algorithm)
+        if (downloaded) return
+        val request: HttpRequest = HttpRequest.newBuilder()
+            .uri(source)
+            .GET()
+            .build()
+        val response = client.send(request, HttpResponse.BodyHandlers.ofInputStream())
+        if (response.statusCode() != 200) throw GradleException("Downloading from $source failed with status code ${response.statusCode()}.")
+        println(response.version())
+        val isValid = copyVerify(response.body(), target, checksum, algorithm)
+        if (!isValid) throw GradleException("Data integrity of downloaded file $source could not be verified, checksums do not match.")
+    }
+    @OptIn(ExperimentalStdlibApi::class)
+    private fun copyVerify(from: InputStream, file: Path, checksum: String, algorithm: String): Boolean {
+        val md = MessageDigest.getInstance(algorithm)
+        val input = DigestInputStream(from, md)
+        Files.copy(input, file, StandardCopyOption.REPLACE_EXISTING)
+        val calculatedChecksum = input.messageDigest.digest().toHexString()
+        if (calculatedChecksum != checksum) Files.deleteIfExists(file)
+        return calculatedChecksum == checksum
+    }
+    @OptIn(ExperimentalStdlibApi::class)
+    private fun verify(file: Path, checksum: String, algorithm: String): Boolean {
+        if (Files.notExists(file)) return false
+        val md = MessageDigest.getInstance(algorithm)
+        DigestInputStream(Files.newInputStream(file), md).use { input ->
+            input.readAllBytes()
+        }
+        val calculatedChecksum = md.digest().toHexString()
+        val isValid = calculatedChecksum == checksum
+        if (!isValid) Files.deleteIfExists(file)
+        return isValid
     }
 }