JNI built in JNI

jni/build.gradle.kts

@@ -2,6 +2,8 @@ plugins {
     kotlin("jvm")
 }
 
+val currentOs = org.gradle.internal.os.OperatingSystem.current()
+
 kotlin {
     explicitApi()
 }
@@ -25,3 +27,46 @@ val generateJniHeaders by tasks.creating(JavaCompile::class) {
         delete(file("${buildDir}/generated/jni-tmp"))
     }
 }
+
+sealed class Cross {
+    abstract fun cmd(target: String, project: Project): List<String>
+    class DockCross(val cross: String) : Cross() {
+        override fun cmd(target: String, project: Project): List<String> = listOf("${project.rootDir}/cross-scripts/dockcross-$cross", "bash", "-c", "CROSS=1 TARGET=$target jni/build.sh")
+    }
+    class MultiArch(val crossTriple: String) : Cross() {
+        override fun cmd(target: String, project: Project): List<String> {
+            val uid = Runtime.getRuntime().exec("id -u").inputStream.use { it.reader().readText() }.trim().toInt()
+            return listOf(
+                "docker", "run", "--rm", "-v", "${project.rootDir.absolutePath}:/workdir",
+                "-e", "CROSS_TRIPLE=$crossTriple", "-e", "TARGET=$target", "-e", "TO_UID=$uid", "-e", "CROSS=1",
+                "multiarch/crossbuild", "jni/build.sh"
+            )
+        }
+    }
+}
+
+val buildNativeJni by tasks.creating {
+    group = "build"
+}
+fun creatingBuildNativeJni(target: String, cross: Cross?) = tasks.creating(Exec::class) {
+    group = "build"
+    dependsOn(generateJniHeaders)
+    dependsOn(":native:buildSecp256k1${target.capitalize()}")
+    buildNativeJni.dependsOn(this)
+
+    inputs.files(projectDir.resolve("build.sh"))
+    outputs.dir(buildDir.resolve("build/cmake/$target"))
+
+    workingDir = rootDir
+    environment("TARGET", target)
+    commandLine((cross?.cmd(target, project) ?: emptyList()) + "jni/build.sh")
+}
+val buildNativeJniDarwin by creatingBuildNativeJni("darwin", if (currentOs.isMacOsX) null else Cross.MultiArch("x86_64-apple-darwin"))
+val buildNativeJniLinux by creatingBuildNativeJni("linux", if (currentOs.isLinux) null else Cross.DockCross("linux-x64"))
+val buildNativeJniMingw by creatingBuildNativeJni("mingw", if (currentOs.isWindows) null else Cross.DockCross("windows-x64"))
+
+afterEvaluate {
+    tasks["clean"].doLast {
+        delete(buildDir.resolve("build/cmake"))
+    }
+}