Improve startup time

[forax]

Hello,
i'm trying to use swc4j but the startup is quite slow on my Mac (M2 Air),
it takes more than 5 seconds to just run
var swc4j = new Swc4j();

If i try to load the native library using the following code, it's still slow but around 400 ms

String libName = "libswc4j-macos-arm64.v.1.3.0.dylib";
URL url = Class.forName("com.caoccao.javet.swc4j.Swc4jNative").getResource("/" + libName);
Path tmpDir = Files.createTempDirectory("swc4j-native");
tmpDir.toFile().deleteOnExit();
Path nativeLibTmpFile = tmpDir.resolve(libName);
nativeLibTmpFile.toFile().deleteOnExit();
try (InputStream in = url.openStream()) {
  Files.copy(in, nativeLibTmpFile);
}
System.load(nativeLibTmpFile.toAbsolutePath().toString());

Compared to your code, this code

• uses createTempDirectory() which is a fresh directory so no purge needed,
• path.toFile().deleteOnExit() so deletion is not an issue
• uses Files.copy() for fast copy

For me, this code is Java 8 compatible and faster.

[caoccao]

I wonder if 5s on you machine is a consistent number. The lib loading should be less than 1s.

[forax]

Sadly it's consistent :(
I can reproduce it inside IntelliJ or using the command line (with all other applications not running).
I've also tested with Java 17 and Java 23, same issue.

Inside a VM (using colima), it takes 184 ms on linux, so it's a macOS issue :(

[forax]

This seems to be related to the "System Integrity Protection" (SIP) in macOS,
a mechanism that prevent to evecute the code of a dynlib which is not authorized.

So it seems that in macOs, it's better if the dynlib is always at the same location so the dynlib is only verified once.

[caoccao]

My other project Javet allows loading the binary from arbitrary folder with proper setting. Swc4j hasn't implemented that yet. But, it's possible to do that.

[forax]

It would be cool :)

[caoccao]

Actually, you are the first one asking for it. Let's see how it works.