initial commit

buildSrc/src/main/java/GolangBuildOptions.kt

@@ -0,0 +1,3 @@
+import java.io.File
+
+data class GolangBuildOptions(val sourceDir: File, val outputDir: File, val platform: String)

buildSrc/src/main/java/GolangBuildTask.kt

@@ -0,0 +1,85 @@
+import org.apache.tools.ant.taskdefs.condition.Os
+import org.gradle.api.GradleException
+import org.gradle.api.tasks.Exec
+import java.io.File
+import java.io.FileReader
+
+import java.util.Properties
+
+open class GolangBuildTask : Exec() {
+    private lateinit var options: GolangBuildOptions
+    private lateinit var abi: String
+
+    override fun exec() {
+        val toolchainRoot = findAndroidNdkPath().resolve("toolchains/llvm/prebuilt/${detectOsType()}/bin")
+        val linkerPrefix = toolChainPrefix()
+        val compilerPrefix = linkerPrefix + options.platform
+
+        if ( !toolchainRoot.exists() )
+            throw GradleException("Compiler not found")
+
+        workingDir = options.sourceDir
+
+        environment.put("GOARCH", golangArch())
+        environment.put("GOOS", "android")
+        environment.put("CGO_ENABLED", "1")
+        environment.put("GOPATH", project.buildDir.resolve("intermediates/gopath").absolutePath)
+        environment.put("CXX", toolchainRoot.resolve(compilerPrefix + "-clang++".exe()).absolutePath)
+        environment.put("CC", toolchainRoot.resolve(compilerPrefix + "-clang".exe()).absolutePath)
+        environment.put("LD", toolchainRoot.resolve(linkerPrefix + "ld".exe()).absolutePath)
+
+        commandLine = listOf("go".exe(), "build", "-buildmode", "c-shared", "-o", options.outputDir.resolve("$abi/libclash.so").absolutePath)
+
+        super.exec()
+    }
+
+    fun setOptions(options: GolangBuildOptions, abi: String) {
+        this.options = options
+        this.abi = abi
+    }
+
+    private fun findAndroidNdkPath(): File {
+        val properties = FileReader(project.rootProject.file("local.properties")).use {
+            Properties().apply { load(it) }
+        }
+
+        return properties.getProperty("ndk.dir")?.let { File(it) }?.takeIf { it.exists() }
+            ?: throw GradleException("Android NDK not found.")
+    }
+
+    private fun detectOsType(): String {
+        return when {
+            Os.isFamily(Os.FAMILY_WINDOWS) -> "linux-x86_64"
+            Os.isFamily(Os.FAMILY_MAC) -> "darwin-x86_64"
+            Os.isFamily(Os.FAMILY_UNIX) -> "linux-x86_64"
+            else -> throw GradleException("Unsupported Build OS ${System.getenv("os.name")}")
+        }
+    }
+
+    private fun golangArch(): String {
+        return when (abi) {
+            "armeabi-v7a" -> "arm"
+            "arm64-v8a" -> "arm64"
+            "x86" -> "i686"
+            "x86_64" -> "amd64"
+            else -> throw GradleException("Unsupported arch $abi")
+        }
+    }
+
+    private fun toolChainPrefix(): String {
+        return when (abi) {
+            "armeabi-v7a" -> "arm-linux-androideabi"
+            "arm64-v8a" -> "aarch64-linux-android"
+            "x86" -> "i686-linux-android"
+            "x86_64" -> "x86_64-linux-android"
+            else -> throw GradleException("Unsupported arch $abi")
+        }
+    }
+
+    private fun String.exe(): String {
+        return if ( Os.isFamily(Os.FAMILY_WINDOWS) )
+            "$this.exe"
+        else
+            this
+    }
+}