feat: start of scripting engine

Cargo.toml

@@ -16,7 +16,6 @@ napi = { version = "3.0.0-beta.11", default-features = false, features = [
 ] }
 napi-derive = "3.0.0-beta.11"
 hex = "0.4.3"
-serde_json = "1.0.128"
 md5 = "0.7.0"
 time-macros = "0.2.22"
 time = "0.3.41"
@@ -27,6 +26,10 @@ tokio-util = { version = "0.7.15", features = ["codec"] }
 rawzip = "0.3.0"
 dyn-clone = "1.0.20"
 flate2 = "1.1.2"
+rhai = "1.22.2"
+mlua = { version = "0.11.2", features = ["luajit"] }
+boa_engine = "0.20.0"
+serde_json = "1.0.143"
 
 [package.metadata.patch]
 crates = ["rawzip"]

__test__/debug.spec.mjs

@@ -0,0 +1,22 @@
+import test from "ava";
+import { DropletHandler, generateManifest } from "../index.js";
+
+test.skip("debug", async (t) => {
+  const handler = new DropletHandler();
+
+  console.log("created handler");
+
+  const manifest = JSON.parse(
+    await new Promise((r, e) =>
+      generateManifest(
+        handler,
+        "./assets/TheGame.zip",
+        (_, __) => {},
+        (_, __) => {},
+        (err, manifest) => (err ? e(err) : r(manifest))
+      )
+    )
+  );
+
+  return t.pass();
+});

__test__/script.spec.mjs

@@ -0,0 +1,62 @@
+import test from "ava";
+import { ScriptEngine } from "../index.js";
+
+test("lua syntax fail", (t) => {
+  const scriptEngine = new ScriptEngine();
+
+  const luaIshCode = `
+    print("hello world);
+    `;
+
+  try {
+    const script = scriptEngine.buildLuaScript(luaIshCode);
+  } catch {
+    return t.pass();
+  }
+  t.fail();
+});
+
+test("js syntax fail", (t) => {
+  const scriptEngine = new ScriptEngine();
+
+  const jsIshCode = `
+    const v = "hello world;
+    `;
+
+  try {
+    const script = scriptEngine.buildJsScript(jsIshCode);
+  } catch {
+    return t.pass();
+  }
+  t.fail();
+});
+
+test("js", (t) => {
+  const scriptEngine = new ScriptEngine();
+
+  const jsModule = `
+    const v = "1" + "2";
+    ["1", "2", "3", v]
+       `;
+
+  const script = scriptEngine.buildJsScript(jsModule);
+
+  scriptEngine.fetchStrings(script);
+
+  t.pass();
+});
+
+test("lua", (t) => {
+  const scriptEngine = new ScriptEngine();
+
+  const luaModule = `
+    local arr = {"1", "2"};
+    return arr;
+    `;
+
+  const script = scriptEngine.buildLuaScript(luaModule);
+
+  scriptEngine.fetchStrings(script);
+
+  t.pass();
+});

__test__/utils.spec.mjs

@@ -1,6 +1,8 @@
 import test from "ava";
 import fs from "node:fs";
 import path from "path";
+import { createHash } from "node:crypto";
+import prettyBytes from "pretty-bytes";
 
 import droplet, { DropletHandler, generateManifest } from "../index.js";
 
@@ -56,7 +58,12 @@ test("read file", async (t) => {
 
   const dropletHandler = new DropletHandler();
 
-  const stream = dropletHandler.readFile(dirName, "TESTFILE");
+  const stream = dropletHandler.readFile(
+    dirName,
+    "TESTFILE",
+    BigInt(0),
+    BigInt(testString.length)
+  );
 
   let finalString = "";
 
@@ -78,7 +85,12 @@ test("read file offset", async (t) => {
   fs.writeFileSync(dirName + "/TESTFILE", testString);
 
   const dropletHandler = new DropletHandler();
-  const stream = dropletHandler.readFile(dirName, "TESTFILE", BigInt(1), BigInt(4));
+  const stream = dropletHandler.readFile(
+    dirName,
+    "TESTFILE",
+    BigInt(1),
+    BigInt(4)
+  );
 
   let finalString = "";
 
@@ -96,10 +108,45 @@ test("read file offset", async (t) => {
   fs.rmSync(dirName, { recursive: true });
 });
 
-test("zip file reader", async (t) => {
-  return t.pass();
+test.skip("zip speed test", async (t) => {
+  t.timeout(100_000_000);
+  const dropletHandler = new DropletHandler();
 
-  t.timeout(10_000);
+  const stream = dropletHandler.readFile("./assets/TheGame.zip", "setup.exe");
+
+  let totalRead = 0;
+  let totalSeconds = 0;
+
+  let lastTime = process.hrtime.bigint();
+  const timeThreshold = BigInt(1_000_000_000);
+  let runningTotal = 0;
+  let runningTime = BigInt(0);
+  for await (const chunk of stream.getStream()) {
+    // Do something with each 'chunk'
+    const currentTime = process.hrtime.bigint();
+    const timeDiff = currentTime - lastTime;
+    lastTime = currentTime;
+    runningTime += timeDiff;
+
+    runningTotal += chunk.length;
+
+    if (runningTime >= timeThreshold) {
+      console.log(`${prettyBytes(runningTotal)}/s`);
+      totalRead += runningTotal;
+      totalSeconds += 1;
+      runningTime = BigInt(0);
+      runningTotal = 0;
+    }
+  }
+
+  const roughAverage = totalRead / totalSeconds;
+
+  console.log(`total rough average: ${prettyBytes(roughAverage)}/s`);
+
+  t.pass();
+});
+
+test.skip("zip manifest test", async (t) => {
   const dropletHandler = new DropletHandler();
   const manifest = JSON.parse(
     await new Promise((r, e) =>
@@ -113,20 +160,61 @@ test("zip file reader", async (t) => {
     )
   );
 
-  const stream = dropletHandler.readFile(
+  for (const [filename, data] of Object.entries(manifest)) {
+    let start = 0;
+    for (const [chunkIndex, length] of data.lengths.entries()) {
+      const hash = createHash("md5");
+      const stream = (
+        await dropletHandler.readFile(
           "./assets/TheGame.zip",
-    "setup.exe",
-    BigInt(10),
-    BigInt(20)
+          filename,
+          BigInt(start),
+          BigInt(start + length)
+        )
+      ).getStream();
+
+      let streamLength = 0;
+      await stream.pipeTo(
+        new WritableStream({
+          write(chunk) {
+            streamLength += chunk.length;
+            hash.update(chunk);
+          },
+        })
       );
 
+      if (streamLength != length)
+        return t.fail(
+          `stream length for chunk index ${chunkIndex} was not expected: real: ${streamLength} vs expected: ${length}`
+        );
 
-  let finalString = "";
-  for await (const chunk of stream.getStream()) {
-    // Do something with each 'chunk'
-    finalString = String.fromCharCode.apply(null, chunk);
-    if(finalString.length > 100) break;
+      const digest = hash.digest("hex");
+      if (data.checksums[chunkIndex] != digest)
+        return t.fail(
+          `checksums did not match for chunk index ${chunkIndex}: real: ${digest} vs expected: ${data.checksums[chunkIndex]}`
+        );
+
+      start += length;
+    }
   }
 
   t.pass();
 });
+
+test.skip("partially compress zip test", async (t) => {
+  const dropletHandler = new DropletHandler();
+
+  const manifest = JSON.parse(
+    await new Promise((r, e) =>
+      generateManifest(
+        dropletHandler,
+        "./assets/my horror game.zip",
+        (_, __) => {},
+        (_, __) => {},
+        (err, manifest) => (err ? e(err) : r(manifest))
+      )
+    )
+  );
+
+  return t.pass();
+});

assets/generate.sh

@@ -1,3 +1,4 @@
-yes "droplet is awesome" | dd of=./setup.exe bs=1024 count=1000000
+# yes "droplet is awesome" | dd of=./setup.exe bs=1024 count=1000000
+dd if=/dev/random of=./setup.exe bs=1024 count=1000000
 zip TheGame.zip setup.exe
 rm setup.exe

index.d.ts

@@ -15,6 +15,19 @@ export declare class JsDropStreamable {
   getStream(): any
 }
 
+export declare class Script {
+
+}
+
+export declare class ScriptEngine {
+  constructor()
+  buildRahiScript(content: string): Script
+  buildLuaScript(content: string): Script
+  buildJsScript(content: string): Script
+  execute(script: Script): void
+  fetchStrings(script: Script): Array<string>
+}
+
 export declare function callAltThreadFunc(tsfn: ((err: Error | null, ) => any)): void
 
 export declare function generateClientCertificate(clientId: string, clientName: string, rootCa: string, rootCaPrivate: string): Array<string>

index.js

@@ -378,6 +378,8 @@ if (!nativeBinding) {
 module.exports = nativeBinding
 module.exports.DropletHandler = nativeBinding.DropletHandler
 module.exports.JsDropStreamable = nativeBinding.JsDropStreamable
+module.exports.Script = nativeBinding.Script
+module.exports.ScriptEngine = nativeBinding.ScriptEngine
 module.exports.callAltThreadFunc = nativeBinding.callAltThreadFunc
 module.exports.generateClientCertificate = nativeBinding.generateClientCertificate
 module.exports.generateManifest = nativeBinding.generateManifest

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@drop-oss/droplet",
-  "version": "2.0.1",
+  "version": "2.3.1",
   "main": "index.js",
   "types": "index.d.ts",
   "napi": {
@@ -24,7 +24,9 @@
   "devDependencies": {
     "@napi-rs/cli": "3.0.0-alpha.91",
     "@types/node": "^22.13.10",
-    "ava": "^6.2.0"
+    "ava": "^6.2.0",
+    "pretty-bytes": "^7.0.1",
+    "tsimp": "^2.0.12"
   },
   "ava": {
     "timeout": "3m",
@@ -51,8 +53,5 @@
   "packageManager": "yarn@4.7.0",
   "repository": {
     "url": "git+https://github.com/Drop-OSS/droplet.git"
-  },
-  "dependencies": {
-    "tsimp": "^2.0.12"
   }
 }

src/lib.rs

@@ -4,6 +4,7 @@
 pub mod manifest;
 pub mod ssl;
 pub mod version;
+pub mod script;
 
 #[macro_use]
 extern crate napi_derive;

src/manifest.rs

@@ -1,10 +1,4 @@
-use std::{
-  collections::HashMap,
-  io::{BufRead, BufReader},
-  path::Path,
-  sync::Arc,
-  thread,
-};
+use std::{collections::HashMap, sync::Arc, thread};
 
 use napi::{
   threadsafe_function::{ThreadsafeFunction, ThreadsafeFunctionCallMode},
@@ -42,10 +36,18 @@ pub fn generate_manifest<'a>(
   log_sfn: ThreadsafeFunction<String>,
   callback_sfn: ThreadsafeFunction<String>,
 ) -> Result<()> {
-  let backend: &mut Box<dyn VersionBackend + Send> =
-    droplet_handler.create_backend_for_path(dir).ok_or(napi::Error::from_reason("Could not create backend for path."))?;
+  let backend: &mut Box<dyn VersionBackend + Send> = droplet_handler
+    .create_backend_for_path(dir)
+    .ok_or(napi::Error::from_reason(
+    "Could not create backend for path.",
+  ))?;
+
+  // This is unsafe (obviously)
+  // But it's allg as long the DropletHandler doesn't get
+  // dropped while we're generating the manifest.
   let backend: &'static mut Box<dyn VersionBackend + Send> =
     unsafe { std::mem::transmute(backend) };
+
   thread::spawn(move || {
     let files = backend.list_files();
 
@@ -55,9 +57,10 @@ pub fn generate_manifest<'a>(
     let total: i32 = files.len() as i32;
     let mut i: i32 = 0;
 
+    let mut buf = [0u8; 1024 * 16];
+
     for version_file in files {
-      let raw_reader = backend.reader(&version_file).unwrap();
-      let mut reader = BufReader::with_capacity(CHUNK_SIZE, raw_reader);
+      let mut reader = backend.reader(&version_file, 0, 0).unwrap();
 
       let mut chunk_data = ChunkData {
         permissions: version_file.permission,
@@ -68,14 +71,28 @@ pub fn generate_manifest<'a>(
 
       let mut chunk_index = 0;
       loop {
+        let mut length = 0;
         let mut buffer: Vec<u8> = Vec::new();
-        reader.fill_buf().unwrap().clone_into(&mut buffer);
-        let length = buffer.len();
+        let mut file_empty = false;
 
-        if length == 0 {
+        loop {
+          let read = reader.read(&mut buf).unwrap();
+
+          length += read;
+
+          // If we're out of data, add this chunk and then move onto the next file
+          if read == 0 {
+            file_empty = true;
             break;
           }
 
+          buffer.extend_from_slice(&buf[0..read]);
+
+          if length >= CHUNK_SIZE {
+            break;
+          }
+        }
+
         let chunk_id = Uuid::new_v4();
         let checksum = md5::compute(buffer).0;
         let checksum_string = hex::encode(checksum);
@@ -88,10 +105,14 @@ pub fn generate_manifest<'a>(
           "Processed chunk {} for {}",
           chunk_index, &version_file.relative_filename
         );
+
         log_sfn.call(Ok(log_str), ThreadsafeFunctionCallMode::Blocking);
 
-        reader.consume(length);
         chunk_index += 1;
+
+        if file_empty {
+          break;
+        }
       }
 
       chunks.insert(version_file.relative_filename, chunk_data);

src/script/mod.rs

@@ -0,0 +1,128 @@
+use boa_engine::{Context, JsValue, Source};
+use mlua::{FromLuaMulti, Function, Lua};
+use napi::Result;
+use rhai::AST;
+
+pub enum ScriptType {
+  Rhai,
+  Lua,
+  Javascript,
+}
+
+#[napi]
+pub struct Script(ScriptInner);
+
+pub enum ScriptInner {
+  Rhai { script: AST },
+  Lua { script: Function },
+  Javascript { script: boa_engine::Script },
+}
+
+#[napi]
+pub struct ScriptEngine {
+  rhai_engine: rhai::Engine,
+  lua_engine: Lua,
+  js_engine: Context,
+}
+
+#[napi]
+impl ScriptEngine {
+  #[napi(constructor)]
+  pub fn new() -> Self {
+    ScriptEngine {
+      rhai_engine: rhai::Engine::new(),
+      lua_engine: Lua::new(),
+      js_engine: Context::default(),
+    }
+  }
+
+  #[napi]
+  pub fn build_rahi_script(&self, content: String) -> Result<Script> {
+    let script = self
+      .rhai_engine
+      .compile(content.clone())
+      .map_err(|e| napi::Error::from_reason(e.to_string()))?;
+    Ok(Script(ScriptInner::Rhai { script }))
+  }
+
+  #[napi]
+  pub fn build_lua_script(&self, content: String) -> Result<Script> {
+    let func = self
+      .lua_engine
+      .load(content.clone())
+      .into_function()
+      .map_err(|e| napi::Error::from_reason(e.to_string()))?;
+    Ok(Script(ScriptInner::Lua { script: func }))
+  }
+
+  #[napi]
+  pub fn build_js_script(&mut self, content: String) -> Result<Script> {
+    let source = Source::from_bytes(content.as_bytes());
+    let script = boa_engine::Script::parse(source, None, &mut self.js_engine)
+      .map_err(|e| napi::Error::from_reason(e.to_string()))?;
+
+    Ok(Script(ScriptInner::Javascript { script }))
+  }
+
+  fn execute_rhai_script<T>(&self, ast: &AST) -> Result<T>
+  where
+    T: Clone + 'static,
+  {
+    let v = self
+      .rhai_engine
+      .eval_ast::<T>(ast)
+      .map_err(|e| napi::Error::from_reason(e.to_string()))?;
+
+    Ok(v)
+  }
+
+  fn execute_lua_script<T>(&self, function: &Function) -> Result<T>
+  where
+    T: FromLuaMulti,
+  {
+    let v = function
+      .call::<T>(())
+      .map_err(|e| napi::Error::from_reason(e.to_string()))?;
+    Ok(v)
+  }
+
+  fn execute_js_script(&mut self, func: &boa_engine::Script) -> Result<JsValue> {
+    let v = func
+      .evaluate(&mut self.js_engine)
+      .map_err(|e| napi::Error::from_reason(e.to_string()))?;
+
+    Ok(v)
+  }
+
+  #[napi]
+  pub fn execute(&mut self, script: &mut Script) -> Result<()> {
+    match &script.0 {
+      ScriptInner::Rhai { script } => {
+        self.execute_rhai_script::<()>(script)?;
+      }
+      ScriptInner::Lua { script } => {
+        self.execute_lua_script::<()>(script)?;
+      }
+      ScriptInner::Javascript { script } => {
+        self.execute_js_script(script)?;
+      }
+    };
+    Ok(())
+  }
+
+  #[napi]
+  pub fn fetch_strings(&mut self, script: &mut Script) -> Result<Vec<String>> {
+    Ok(match &script.0 {
+      ScriptInner::Rhai { script } => self.execute_rhai_script(script)?,
+      ScriptInner::Lua { script } => self.execute_lua_script(script)?,
+      ScriptInner::Javascript { script } => {
+        let v = self.execute_js_script(script)?;
+
+        serde_json::from_value(
+          v.to_json(&mut self.js_engine)
+            .map_err(|e| napi::Error::from_reason(e.to_string()))?,
+        ).map_err(|e| napi::Error::from_reason(e.to_string()))?
+      }
+    })
+  }
+}

src/version/backends.rs

@@ -2,17 +2,18 @@
 use std::os::unix::fs::PermissionsExt;
 use std::{
   fs::{self, metadata, File},
-  io::{self, Read, Sink},
+  io::{self, Read, Seek, SeekFrom, Sink},
   path::{Path, PathBuf},
   sync::Arc,
 };
 
 use flate2::read::DeflateDecoder;
 use rawzip::{
-  FileReader, ZipArchive, ZipArchiveEntryWayfinder, ZipEntry, ZipReader, RECOMMENDED_BUFFER_SIZE,
+  CompressionMethod, FileReader, ZipArchive, ZipArchiveEntryWayfinder, ZipEntry,
+  ZipVerifier, RECOMMENDED_BUFFER_SIZE,
 };
 
-use crate::version::types::{MinimumFileObject, Skippable, VersionBackend, VersionFile};
+use crate::version::types::{MinimumFileObject, VersionBackend, VersionFile};
 
 pub fn _list_files(vec: &mut Vec<PathBuf>, path: &Path) {
   if metadata(path).unwrap().is_dir() {
@@ -52,8 +53,21 @@ impl VersionBackend for PathVersionBackend {
     results
   }
 
-  fn reader(&mut self, file: &VersionFile) -> Option<Box<dyn MinimumFileObject + 'static>> {
-    let file = File::open(self.base_dir.join(file.relative_filename.clone())).ok()?;
+  fn reader(
+    &mut self,
+    file: &VersionFile,
+    start: u64,
+    end: u64,
+  ) -> Option<Box<dyn MinimumFileObject + 'static>> {
+    let mut file = File::open(self.base_dir.join(file.relative_filename.clone())).ok()?;
+
+    if start != 0 {
+      file.seek(SeekFrom::Start(start)).ok()?;
+    }
+
+    if end != 0 {
+      return Some(Box::new(file.take(end - start)));
+    }
 
     return Some(Box::new(file));
   }
@@ -103,31 +117,72 @@ impl ZipVersionBackend {
   pub fn new_entry<'archive>(
     &self,
     entry: ZipEntry<'archive, FileReader>,
+    compression_method: CompressionMethod,
+    start: u64,
+    end: u64,
   ) -> ZipFileWrapper<'archive> {
-    let deflater = DeflateDecoder::new(entry.reader());
-    ZipFileWrapper { reader: deflater }
+    let deflater: Box<dyn Read + Send + 'archive> = match compression_method {
+      CompressionMethod::Store => Box::new(entry.reader()),
+      CompressionMethod::Deflate => Box::new(DeflateDecoder::new(entry.reader())),
+      CompressionMethod::Deflate64 => Box::new(DeflateDecoder::new(entry.reader())),
+      _ => panic!(
+        "unsupported decompression algorithm: {:?}",
+        compression_method
+      ),
+    };
+
+    let mut verifier = entry.verifying_reader(deflater);
+    if start != 0 {
+      io::copy(&mut (&mut verifier).take(start), &mut Sink::default()).unwrap();
+    }
+
+    ZipFileWrapper {
+      reader: verifier,
+      limit: (end - start) as usize,
+      current: 0,
+    }
   }
 }
 
 pub struct ZipFileWrapper<'archive> {
-  reader: DeflateDecoder<ZipReader<'archive, FileReader>>,
+  reader: ZipVerifier<'archive, Box<dyn Read + Send + 'archive>, FileReader>,
+  limit: usize,
+  current: usize,
 }
 
+/**
+ * This read implemention is a result of debugging hell
+ * It should probably be replaced with a .take() call.
+ */
 impl<'a> Read for ZipFileWrapper<'a> {
   fn read(&mut self, buf: &mut [u8]) -> std::io::Result<usize> {
+    let has_limit = self.limit != 0;
+
+    // End this stream if the read is the right size
+    if has_limit {
+      if self.current >= self.limit {
+        return Ok(0);
+      }
+    }
+
     let read = self.reader.read(buf)?;
-    Ok(read)
+    if self.limit != 0 {
+      self.current += read;
+      if self.current > self.limit {
+        let over = self.current - self.limit;
+        return Ok(read - over);
+      }
+    }
+    return Ok(read);
   }
 }
-impl<'a> Skippable for ZipFileWrapper<'a> {
-  fn skip(&mut self, amount: u64) {
-    io::copy(&mut self.reader.by_ref().take(amount), &mut Sink::default()).unwrap();
-  }
-}
-impl<'a> MinimumFileObject for ZipFileWrapper<'a> {}
+//impl<'a> MinimumFileObject for ZipFileWrapper<'a> {}
 
 impl ZipVersionBackend {
-  fn find_wayfinder(&mut self, filename: &str) -> Option<ZipArchiveEntryWayfinder> {
+  fn find_wayfinder(
+    &mut self,
+    filename: &str,
+  ) -> Option<(ZipArchiveEntryWayfinder, CompressionMethod)> {
     let read_buffer = &mut [0u8; RECOMMENDED_BUFFER_SIZE];
     let mut entries = self.archive.entries(read_buffer);
     let entry = loop {
@@ -142,7 +197,7 @@ impl ZipVersionBackend {
 
     let wayfinder = entry.wayfinder();
 
-    Some(wayfinder)
+    Some((wayfinder, entry.compression_method()))
   }
 }
 impl VersionBackend for ZipVersionBackend {
@@ -163,17 +218,22 @@ impl VersionBackend for ZipVersionBackend {
     results
   }
 
-  fn reader(&mut self, file: &VersionFile) -> Option<Box<dyn MinimumFileObject + '_>> {
-    let wayfinder = self.find_wayfinder(&file.relative_filename)?;
+  fn reader(
+    &mut self,
+    file: &VersionFile,
+    start: u64,
+    end: u64,
+  ) -> Option<Box<dyn MinimumFileObject + '_>> {
+    let (wayfinder, compression_method) = self.find_wayfinder(&file.relative_filename)?;
     let local_entry = self.archive.get_entry(wayfinder).unwrap();
 
-    let wrapper = self.new_entry(local_entry);
+    let wrapper = self.new_entry(local_entry, compression_method, start, end);
 
-    Some(Box::new(wrapper))
+    Some(Box::new(wrapper) as Box<dyn MinimumFileObject>)
   }
 
   fn peek_file(&mut self, sub_path: String) -> Option<VersionFile> {
-    let entry = self.find_wayfinder(&sub_path)?;
+    let (entry, _) = self.find_wayfinder(&sub_path)?;
 
     Some(VersionFile {
       relative_filename: sub_path,

src/version/types.rs

@@ -1,6 +1,5 @@
 use std::{
-  fmt::Debug,
-  io::{Read, Seek, SeekFrom},
+  fmt::Debug, io::Read
 };
 
 use dyn_clone::DynClone;
@@ -13,36 +12,26 @@ pub struct VersionFile {
   pub size: u64,
 }
 
-pub trait Skippable {
-  fn skip(&mut self, amount: u64);
-}
-impl<T> Skippable for T
-where
-  T: Seek,
-{
-  fn skip(&mut self, amount: u64) {
-    self.seek(SeekFrom::Start(amount)).unwrap();
-  }
-}
-
-pub trait MinimumFileObject: Read + Send + Skippable {}
-impl<T: Read + Send + Seek> MinimumFileObject for T {}
+pub trait MinimumFileObject: Read + Send  {}
+impl<T: Read + Send> MinimumFileObject for T {}
 
 // Intentionally not a generic, because of types in read_file
 pub struct ReadToAsyncRead<'a> {
   pub inner: Box<dyn Read + Send + 'a>,
 }
 
+const ASYNC_READ_BUFFER_SIZE: usize = 8128;
+
 impl<'a> AsyncRead for ReadToAsyncRead<'a> {
   fn poll_read(
     mut self: std::pin::Pin<&mut Self>,
     _cx: &mut std::task::Context<'_>,
     buf: &mut tokio::io::ReadBuf<'_>,
   ) -> std::task::Poll<io::Result<()>> {
-    let mut read_buf = [0u8; 8192];
-    let var_name = self.inner.read(&mut read_buf).unwrap();
-    let amount = var_name.min(buf.remaining());
-    buf.put_slice(&read_buf[0..amount]);
+    let mut read_buf = [0u8; ASYNC_READ_BUFFER_SIZE];
+    let read_size = ASYNC_READ_BUFFER_SIZE.min(buf.remaining());
+    let read = self.inner.read(&mut read_buf[0..read_size]).unwrap();
+    buf.put_slice(&read_buf[0..read]);
     std::task::Poll::Ready(Ok(()))
   }
 }
@@ -50,7 +39,7 @@ impl<'a> AsyncRead for ReadToAsyncRead<'a> {
 pub trait VersionBackend: DynClone {
   fn list_files(&mut self) -> Vec<VersionFile>;
   fn peek_file(&mut self, sub_path: String) -> Option<VersionFile>;
-  fn reader(&mut self, file: &VersionFile) -> Option<Box<dyn MinimumFileObject + '_>>;
+  fn reader(&mut self, file: &VersionFile, start: u64, end: u64) -> Option<Box<dyn MinimumFileObject + '_>>;
 }
 
 dyn_clone::clone_trait_object!(VersionBackend);

src/version/utils.rs

@@ -1,4 +1,6 @@
-use std::{collections::HashMap, fs::File, io::Read, path::Path};
+use std::{
+  collections::HashMap, fs::File, path::Path
+};
 
 use napi::{bindgen_prelude::*, sys::napi_value__, tokio_stream::StreamExt};
 use tokio_util::codec::{BytesCodec, FramedRead};
@@ -115,20 +117,16 @@ impl<'a> DropletHandler<'a> {
         size: 0,       // Shouldn't matter
       };
       // Use `?` operator for cleaner error propagation from `Option`
-      let mut reader = backend.reader(&version_file).ok_or(napi::Error::from_reason("Failed to create reader."))?;
+      let reader = backend
+        .reader(
+          &version_file,
+          start.map(|e| e.get_u64().1).unwrap_or(0),
+          end.map(|e| e.get_u64().1).unwrap_or(0),
+        )
+        .ok_or(napi::Error::from_reason("Failed to create reader."))?;
 
-      if let Some(skip) = start.clone() {
-        reader.skip(skip.get_u64().1.into());
-        // io::copy(&mut reader.by_ref().take(skip.into()), &mut io::sink()).unwrap();
-      }
-
-      let async_reader = if let Some(limit) = end {
-        let amount = limit.get_u64().1 - start.map_or(Some(0), |v| Some(v.get_u64().1)).unwrap();
-        ReadToAsyncRead {
-          inner: Box::new(reader.take(amount.into())),
-        }
-      } else {
-        ReadToAsyncRead { inner: reader }
+      let async_reader = ReadToAsyncRead {
+        inner: reader,
       };
 
       // Create a FramedRead stream with BytesCodec for chunking
@@ -147,9 +145,7 @@ impl<'a> DropletHandler<'a> {
       Ok(ReadableStream::create_with_stream_bytes(&env, stream).unwrap())
     })?;
 
-    Ok(JsDropStreamable {
-      inner: stream,
-    })
+    Ok(JsDropStreamable { inner: stream })
   }
 }
 

yarn.lock

@@ -12,6 +12,7 @@ __metadata:
     "@napi-rs/cli": "npm:3.0.0-alpha.91"
     "@types/node": "npm:^22.13.10"
     ava: "npm:^6.2.0"
+    pretty-bytes: "npm:^7.0.1"
     tsimp: "npm:^2.0.12"
   languageName: unknown
   linkType: soft
@@ -2432,6 +2433,13 @@ __metadata:
   languageName: node
   linkType: hard
 
+"pretty-bytes@npm:^7.0.1":
+  version: 7.0.1
+  resolution: "pretty-bytes@npm:7.0.1"
+  checksum: 10c0/14ffb503d2de3588042c722848062a4897e6faece1694e0c83ba5669ec003d73311d946d50d2b3c6099a6a306760011b8446ee3cf9cf86eca13a454a8f1c47cb
+  languageName: node
+  linkType: hard
+
 "pretty-ms@npm:^9.1.0":
   version: 9.2.0
   resolution: "pretty-ms@npm:9.2.0"