Include native libraries in jar by shifting folder structure

Author: TheBlueMatt

.github/workflows/build.yml

@@ -52,7 +52,7 @@ jobs:
       - name: Run Java Tests against Debug Bindings
         run: |
           rm liblightningjni.so
-          ln -s liblightningjni_debug.so liblightningjni.so
+          ln -s liblightningjni_debug_Linux-amd64.so liblightningjni.so
           export LD_LIBRARY_PATH=.
           export LD_PRELOAD=/usr/lib/llvm-11/lib/clang/11.0.1/lib/linux/libclang_rt.asan-x86_64.so
           export ASAN_OPTIONS=detect_leaks=0
@@ -73,8 +73,6 @@ jobs:
           fi
           echo "Using $LDK_GARBAGECOLLECTED_GIT_OVERRIDE as git version"
           ./genbindings.sh ./ldk-c-bindings/ "-I/usr/lib/jvm/java-11-openjdk-amd64/include/ -I/usr/lib/jvm/java-11-openjdk-amd64/include/linux/" false false
-      - name: Check latest headers are in git
+      - name: Check latest headers and release lib are in git
         run: |
-          # For some reason the debug library is not deterministic, this may be fixed in a future rustc
-          git checkout liblightningjni_debug.so
           git diff --exit-code

genbindings.sh

@@ -19,9 +19,21 @@ else
 	COMMON_COMPILE="clang -std=c11 -Wall -Wextra -Wno-unused-parameter -Wno-ignored-qualifiers -Wno-unused-function -Wno-nullability-completeness -Wno-pointer-sign -Wdate-time -ffile-prefix-map=$(pwd)="
 fi
 
-if [ "$LDK_TARGET" != "" ]; then
-	LDK_TARGET_SUFFIX="_$LDK_TARGET"
+TARGET_STRING="$LDK_TARGET"
+if [ "$TARGET_STRING" = "" ]; then
+	# We assume clang-style $CC --version here, but worst-case we just get an empty suffix
+	TARGET_STRING="$($CC --version | grep Target | awk '{ print $2 }')"
 fi
+case "$TARGET_STRING" in
+	"x86_64-pc-linux"*)
+		LDK_TARGET_SUFFIX="_Linux-amd64" ;;
+	"x86_64-apple-darwin"*)
+		LDK_TARGET_SUFFIX="_MacOSX-x86_64" ;;
+	"aarch64-apple-darwin"*)
+		LDK_TARGET_SUFFIX="_MacOSX-aarch64" ;;
+	*)
+		LDK_TARGET_SUFFIX=""
+esac
 if [ "$LDK_TARGET_CPU" = "" ]; then
 	LDK_TARGET_CPU="sandybridge"
 fi
@@ -68,6 +80,10 @@ if [ "$3" = "true" ]; then
 else
 	[ "$IS_MAC" = "false" ] && COMPILE="$COMPILE -Wl,--version-script=libcode.version -fuse-ld=lld"
 	$COMPILE -o liblightningjni_release$LDK_TARGET_SUFFIX.so -flto -O3 -I"$1"/lightning-c-bindings/include/ $2 src/main/jni/bindings.c "$1"/lightning-c-bindings/target/$LDK_TARGET/release/libldk.a
+	if [ "$LDK_TARGET_SUFFIX" != "" ]; then
+		# Copy to JNI native directory for inclusion in JARs
+		cp liblightningjni_release$LDK_TARGET_SUFFIX.so src/main/resources/liblightningjni$LDK_TARGET_SUFFIX.nativelib
+	fi
 fi
 
 echo "Creating TS bindings..."

java_strings.py

@@ -24,6 +24,12 @@ def __init__(self, DEBUG: bool, target: Target, **kwargs):
 
         self.bindings_header = """package org.ldk.impl;
 import org.ldk.enums.*;
+import java.io.File;
+import java.io.InputStream;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.StandardCopyOption;
 
 public class bindings {
 	public static class VecOrSliceDef {
@@ -35,7 +41,24 @@ def __init__(self, DEBUG: bool, target: Target, **kwargs):
 		}
 	}
 	static {
-		System.loadLibrary(\"lightningjni\");
+		try {
+			// Try to load natively first, this works on Android and in testing.
+			System.loadLibrary(\"lightningjni\");
+		} catch (UnsatisfiedLinkError _ignored) {
+			// Otherwise try to load from the library jar.
+			File tmpdir = new File(System.getProperty("java.io.tmpdir"), "ldk-java-nativelib");
+			tmpdir.mkdir(); // If it fails to create, assume it was there already
+			tmpdir.deleteOnExit();
+			String libname = "liblightningjni_" + System.getProperty("os.name").replaceAll(" ", "") +
+				"-" + System.getProperty("os.arch").replaceAll(" ", "") + ".nativelib";
+			try (InputStream is = bindings.class.getResourceAsStream("/" + libname)) {
+				Path libpath = new File(tmpdir.toPath().toString(), "liblightningjni.so").toPath();
+				Files.copy(is, libpath, StandardCopyOption.REPLACE_EXISTING);
+				Runtime.getRuntime().load(libpath.toString());
+			} catch (IOException e) {
+				throw new IllegalArgumentException(e);
+			}
+		}
 		init(java.lang.Enum.class, VecOrSliceDef.class);
 		init_class_cache();
 		if (!get_lib_version_string().equals(get_ldk_java_bindings_version()))