Android loading may fallback to standard JVM (#9)

* Android loading may fallback to standard JVM

* Java code must target JVM 1.8 in order to be compatible Android.

Co-authored-by: Salomon BRYS <salomon@kodein.net>

build.gradle.kts

@@ -24,7 +24,7 @@ buildscript {
 
 allprojects {
     group = "fr.acinq.secp256k1"
-    version = "0.2.1-1.4-M3"
+    version = "0.3.0-1.4-M3"
 
     repositories {
         jcenter()

jni/android/src/main/java/fr/acinq/secp256k1/jni/NativeSecp256k1AndroidLoader.kt

@@ -0,0 +1,31 @@
+package fr.acinq.secp256k1.jni
+
+import android.util.Log
+import fr.acinq.secp256k1.Secp256k1
+import fr.acinq.secp256k1.NativeSecp256k1
+import java.util.*
+
+public object NativeSecp256k1AndroidLoader {
+
+    @JvmStatic
+    @Synchronized
+    @Throws(Exception::class)
+    fun load(): Secp256k1 {
+        try {
+            System.loadLibrary("secp256k1-jni")
+            return NativeSecp256k1
+        } catch (ex: UnsatisfiedLinkError) {
+            // Purposefully not using Android Log
+            println("Could not load Android Secp256k1. Trying to extract JVM platform specific version.")
+            try {
+                val cls = Class.forName("fr.acinq.secp256k1.jni.NativeSecp256k1JvmLoader")
+                val load = cls.getMethod("load")
+                return load.invoke(null) as Secp256k1
+            } catch (_: ClassNotFoundException) {
+                throw ex
+            }
+
+        }
+    }
+
+}

jni/android/src/main/kotlin/fr/acinq/secp256k1/jni/NativeSecp256k1Loader.kt

@@ -1,16 +0,0 @@
-package fr.acinq.secp256k1.jni
-
-import fr.acinq.secp256k1.Secp256k1
-import fr.acinq.secp256k1.NativeSecp256k1
-
-public object NativeSecp256k1Loader {
-
-    @JvmStatic
-    @Synchronized
-    @Throws(Exception::class)
-    fun load(): Secp256k1 {
-        System.loadLibrary("secp256k1-jni")
-        return NativeSecp256k1
-    }
-
-}

jni/build.gradle.kts

@@ -3,6 +3,11 @@ plugins {
     `maven-publish`
 }
 
+java {
+    sourceCompatibility = JavaVersion.VERSION_1_8
+    targetCompatibility = JavaVersion.VERSION_1_8
+}
+
 kotlin {
     explicitApi()
 }

jni/jvm/src/main/kotlin/fr/acinq/secp256k1/jni/NativeSecp256k1JvmLoader.kt

@@ -14,7 +14,7 @@ import java.util.*
 *
 * @author leo
 */
-public object NativeSecp256k1Loader {
+public object NativeSecp256k1JvmLoader {
    private var extracted = false
 
    /**
@@ -106,7 +106,7 @@ public object NativeSecp256k1Loader {
        val extractedLckFile = File(targetDirectory, extractedLckFileName)
        return try {
            // Extract a native library file into the target directory
-           val reader = NativeSecp256k1Loader::class.java.getResourceAsStream(libPath)
+           val reader = NativeSecp256k1JvmLoader::class.java.getResourceAsStream(libPath)
            if (!extractedLckFile.exists()) {
                FileOutputStream(extractedLckFile).close()
            }
@@ -132,7 +132,7 @@ public object NativeSecp256k1Loader {
            extractedLibFile.setExecutable(true)
 
            // Check whether the contents are properly copied from the resource folder
-           NativeSecp256k1Loader::class.java.getResourceAsStream(libPath).use { nativeIn ->
+           NativeSecp256k1JvmLoader::class.java.getResourceAsStream(libPath).use { nativeIn ->
                FileInputStream(extractedLibFile).use { extractedLibIn ->
                    if (!nativeIn.contentsEquals(extractedLibIn)) {
                        throw RuntimeException(
@@ -196,9 +196,9 @@ public object NativeSecp256k1Loader {
        }
 
        // Load the os-dependent library from the jar file
-       val packagePath = NativeSecp256k1Loader::class.java.getPackage().name.replace("\\.".toRegex(), "/")
+       val packagePath = NativeSecp256k1JvmLoader::class.java.getPackage().name.replace("\\.".toRegex(), "/")
        val embeddedLibraryPath = "/$packagePath/native/${OSInfo.nativeSuffix}"
-       val hasNativeLib = NativeSecp256k1Loader::class.java.getResource("$embeddedLibraryPath/$libraryName") != null
+       val hasNativeLib = NativeSecp256k1JvmLoader::class.java.getResource("$embeddedLibraryPath/$libraryName") != null
        if (!hasNativeLib) {
            error("No native library found: at $embeddedLibraryPath/$libraryName")
        }

src/jvmMain/kotlin/fr/acinq/secp256k1/Secp256k1Jvm.kt

@@ -16,15 +16,20 @@
 
 package fr.acinq.secp256k1
 
-import java.lang.IllegalStateException
+import java.util.*
 
 
-internal actual fun getSecpk256k1(): Secp256k1 {
+private fun tryLoad(platform: String): Secp256k1? {
     try {
-        val cls = Class.forName("fr.acinq.secp256k1.jni.NativeSecp256k1Loader")
+        val cls = Class.forName("fr.acinq.secp256k1.jni.NativeSecp256k1${platform.capitalize(Locale.ROOT)}Loader")
         val load = cls.getMethod("load")
         return load.invoke(null) as Secp256k1
     } catch (ex: ClassNotFoundException) {
-        throw IllegalStateException("Could not load native Secp256k1 JNI library. Have you added the JNI dependency?", ex)
+        return null
     }
 }
+
+internal actual fun getSecpk256k1(): Secp256k1 =
+    tryLoad("android")
+        ?: tryLoad("jvm")
+        ?: error("Could not load native Secp256k1 JNI library. Have you added the JNI dependency?")