Run prepare only when needed

.gitignore

@@ -29,7 +29,6 @@ buildAllJars/
 relocate_natives/.venv/
 relocate_natives/__pycache__/
 relocate_natives/apple-codesign/
-relocate_natives/cache/
 
 # file from notepad++
 *.bak

.gitlab-ci.yml

@@ -17,9 +17,6 @@ variables:
 # These can be extended so code is a bit less duplicated
 .build_java:
   #image: eclipse-temurin:17
-  before_script:
-    - apt-get update
-    - apt-get install python3 python3-pip python-is-python3 python3-venv -y --no-install-recommends
   cache:
     key: "gradleCache_$CI_JOB_NAME_SLUG"
     policy: pull-push

build.gradle

@@ -106,24 +106,12 @@ forgix {
 
 
 class NativeTransformer implements Transformer {
-    private boolean enabled = false
     private final HashMap<String, String> replacements = new HashMap()
     private final HashMap<String, byte[]> rewrittenFiles = new HashMap()
     private var nativeRelocator
 
     public File rootDir
 
-    NativeTransformer() {
-        try {
-            int exitCode = Runtime.getRuntime().exec(new String[]{"python", "--version"}).waitFor()
-            if (exitCode == 0) {
-                enabled = true
-            }
-        } catch (IOException e) {
-            println(e)
-        }
-    }
-
     void relocateNative(String target, String replacement) {
         if (replacement.length() > target.length()) {
             throw new GradleException("Length of value \"${replacement}\" exceeds the length of \"${target}\": ${replacement.length()} > ${target.length()}")
@@ -132,22 +120,15 @@ class NativeTransformer implements Transformer {
         replacements.put(target, replacement)
     }
 
-    void before(Closure closure) {
-        if (enabled)
-            closure.run()
-    }
-
-
     @Override
     boolean canTransformResource(@Nonnull FileTreeElement element) {
-        return enabled && replacements.keySet().stream().anyMatch {
+        return replacements.keySet().stream().anyMatch {
             element.name.startsWith(it as String)
         }
     }
 
     @Override
     void transform(@Nonnull TransformerContext context) {
-        println("Transforming $context.path...")
         byte[] content = context.is.readAllBytes()
 
         if (nativeRelocator == null) {
@@ -395,16 +376,13 @@ subprojects { p ->
         // Sqlite Database
         // librariesLocation isn't used because it's too long for replacing paths in native libraries
         // Allowing strings larger than the original string would require shifting the entire binary's contents
-        transform(NativeTransformer) {
-            rootDir = project.rootDir
-
-            before {
         relocate "org.sqlite", "dh_sqlite", {
             exclude "org/sqlite/native/**"
         }
         relocate "jdbc:sqlite", "jdbc:dh_sqlite"
-            }
 
+        transform(NativeTransformer) {
+            rootDir = project.rootDir
             relocateNative "org/sqlite", "dh_sqlite"
             relocateNative "org_sqlite", "dh_1sqlite"
         }

buildSrc/src/main/java/NativeRelocator.java

@@ -12,14 +12,15 @@ class NativeRelocator
 	/**
 	 * Initializes the NativeRelocator by preparing the environment if necessary.
 	 * Executes the appropriate preparation script based on the OS.
-	 *
-	 * @throws Exception if the preparation script fails or an unsupported OS is detected.
 	 */
-	NativeRelocator(Path rootDirectory) throws Exception
+	NativeRelocator(Path rootDirectory)
 	{
 		this.rootDirectory = rootDirectory;
 		this.cacheRoot = this.rootDirectory.resolve("cache");
+	}
 	
+	private void prepare() throws Exception
+	{
 		if (this.rootDirectory.resolve(".venv").toFile().exists())
 		{
 			return;
@@ -196,6 +197,9 @@ class NativeRelocator
 			return Files.readAllBytes(outputFilePath);
 		}
 		
+		System.out.println("Relocating to " + outputPath + "...");
+		this.prepare();
+		
 		for (Map.Entry<String, String> replacement : replacements.entrySet())
 		{
 			this.replaceInNullTerminatedStrings(content, replacement.getKey(), replacement.getValue());

gradle.properties

@@ -23,6 +23,7 @@ manifold_version=2024.1.37
 nightconfig_version=3.6.6
 lz4_version=1.8.0
 xz_version=1.9
+# Before updating, read relocate_natives/README.md
 sqlite_jdbc_version=3.47.2.0
 # 8.2.1 is the newest version we can use since that's the version MC 1.16.5 uses 
 fastutil_version=8.2.1

relocate_natives/README.md

@@ -0,0 +1,46 @@
+This directory contains the native files of libraries that were modified for relocation. They will be copied from here during the normal build steps.
+
+Before adding/updating a library, make sure you have Python 3.8+ installed and check the instructions below.
+
+How to add a library's natives:
+
+1. In `build.gradle`:
+
+- Make sure the target package is the same length or shorter (untested) than the source package. Underscores in native methods will take 2 characters so account for that as well.
+- Exclude the native files and add them as `relocateNative` (see example).
+
+Example:
+
+```groovy
+relocate "org.sqlite", "dh_sqlite", {
+    exclude "org/sqlite/native/**"
+}
+
+transform(NativeTransformer) {
+    // NativeTransformer configuration
+    rootDir = project.rootDir
+
+    // Replace native strings, e.g. used in calls back to Java
+    relocateNative "org/sqlite", "dh_sqlite"
+    // Rename native methods used when calling from Java
+    relocateNative "org_sqlite", "dh_1sqlite"
+}
+```
+
+How to update a library's natives:
+
+1. Delete the library's folder in cache/.
+2. It will repopulate during the next build.
+
+Why does this step exist?
+
+- Native files are not handled by the shadow plugin correctly.
+- I preferred it as a more streamlined approach, although a bit hacky.
+- Possible alternatives:
+    - Use edited libraries' source code: although more straightforward, it requires maintaining and updating the repositories for the libraries being added
+    - Interfacing with the necessary libraries directly: an absolute mess for technical reasons
+
+What are libraries used?
+
+- LIEF: for fixing binaries after replacing strings
+- apple-codesign: for re-signing Mac binaries, since their signatures get invalidated after previous steps