BREAKING(core): Remove control slice from ops (#6048)

18 files changed, 112 insertions, 152 deletions

diff --git a/Cargo.lock b/Cargo.lock
index 59c9adce7..5c5998cf2 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -441,6 +441,7 @@ dependencies = [
  "log 0.4.8",
  "rusty_v8",
  "serde_json",
+ "smallvec 1.4.0",
  "tokio",
  "url",
 ]
diff --git a/cli/js/globals.ts b/cli/js/globals.ts
index c73a2a6ab..4548c8304 100644
--- a/cli/js/globals.ts
+++ b/cli/js/globals.ts
@@ -77,14 +77,9 @@ declare global {
 
   interface DenoCore {
     print(s: string, isErr?: boolean): void;
-    dispatch(
-      opId: number,
-      control: Uint8Array,
-      ...zeroCopy: ArrayBufferView[]
-    ): Uint8Array | null;
+    dispatch(opId: number, ...zeroCopy: ArrayBufferView[]): Uint8Array | null;
     dispatchByName(
       opName: string,
-      control: Uint8Array,
       ...zeroCopy: ArrayBufferView[]
     ): Uint8Array | null;
     setAsyncHandler(opId: number, cb: (msg: Uint8Array) => void): void;
@@ -101,11 +96,7 @@ declare global {
 
     recv(cb: (opId: number, msg: Uint8Array) => void): void;
 
-    send(
-      opId: number,
-      control: null | ArrayBufferView,
-      ...data: ArrayBufferView[]
-    ): null | Uint8Array;
+    send(opId: number, ...data: ArrayBufferView[]): null | Uint8Array;
 
     setMacrotaskCallback(cb: () => boolean): void;
 
diff --git a/cli/ops/dispatch_json.rs b/cli/ops/dispatch_json.rs
index 97a02991f..26ffc7d33 100644
--- a/cli/ops/dispatch_json.rs
+++ b/cli/ops/dispatch_json.rs
@@ -46,7 +46,7 @@ struct AsyncArgs {
 
 pub fn json_op<D>(
   d: D,
-) -> impl Fn(&mut CoreIsolateState, &[u8], &mut [ZeroCopyBuf]) -> Op
+) -> impl Fn(&mut CoreIsolateState, &mut [ZeroCopyBuf]) -> Op
 where
   D: Fn(
     &mut CoreIsolateState,
@@ -54,10 +54,9 @@ where
     &mut [ZeroCopyBuf],
   ) -> Result<JsonOp, OpError>,
 {
-  move |isolate_state: &mut CoreIsolateState,
-        control: &[u8],
-        zero_copy: &mut [ZeroCopyBuf]| {
-    let async_args: AsyncArgs = match serde_json::from_slice(control) {
+  move |isolate_state: &mut CoreIsolateState, zero_copy: &mut [ZeroCopyBuf]| {
+    assert!(!zero_copy.is_empty(), "Expected JSON string at position 0");
+    let async_args: AsyncArgs = match serde_json::from_slice(&zero_copy[0]) {
       Ok(args) => args,
       Err(e) => {
         let buf = serialize_result(None, Err(OpError::from(e)));
@@ -67,9 +66,9 @@ where
     let promise_id = async_args.promise_id;
     let is_sync = promise_id.is_none();
 
-    let result = serde_json::from_slice(control)
+    let result = serde_json::from_slice(&zero_copy[0])
       .map_err(OpError::from)
-      .and_then(|args| d(isolate_state, args, zero_copy));
+      .and_then(|args| d(isolate_state, args, &mut zero_copy[1..]));
 
     // Convert to Op
     match result {
diff --git a/cli/ops/dispatch_minimal.rs b/cli/ops/dispatch_minimal.rs
index eac5ad055..45b90ef81 100644
--- a/cli/ops/dispatch_minimal.rs
+++ b/cli/ops/dispatch_minimal.rs
@@ -116,14 +116,13 @@ fn test_parse_min_record() {
 
 pub fn minimal_op<D>(
   d: D,
-) -> impl Fn(&mut CoreIsolateState, &[u8], &mut [ZeroCopyBuf]) -> Op
+) -> impl Fn(&mut CoreIsolateState, &mut [ZeroCopyBuf]) -> Op
 where
   D: Fn(&mut CoreIsolateState, bool, i32, &mut [ZeroCopyBuf]) -> MinimalOp,
 {
-  move |isolate_state: &mut CoreIsolateState,
-        control: &[u8],
-        zero_copy: &mut [ZeroCopyBuf]| {
-    let mut record = match parse_min_record(control) {
+  move |isolate_state: &mut CoreIsolateState, zero_copy: &mut [ZeroCopyBuf]| {
+    assert!(!zero_copy.is_empty(), "Expected record at position 0");
+    let mut record = match parse_min_record(&zero_copy[0]) {
       Some(r) => r,
       None => {
         let e = OpError::type_error("Unparsable control buffer".to_string());
@@ -138,7 +137,7 @@ where
     };
     let is_sync = record.promise_id == 0;
     let rid = record.arg;
-    let min_op = d(isolate_state, is_sync, rid, zero_copy);
+    let min_op = d(isolate_state, is_sync, rid, &mut zero_copy[1..]);
 
     match min_op {
       MinimalOp::Sync(sync_result) => Op::Sync(match sync_result {
diff --git a/cli/ops/plugin.rs b/cli/ops/plugin.rs
index 775178f1e..16debac50 100644
--- a/cli/ops/plugin.rs
+++ b/cli/ops/plugin.rs
@@ -110,9 +110,9 @@ impl<'a> plugin_api::Interface for PluginInterface<'a> {
     let plugin_lib = self.plugin_lib.clone();
     self.isolate_state.op_registry.register(
       name,
-      move |isolate_state, control, zero_copy| {
+      move |isolate_state, zero_copy| {
         let mut interface = PluginInterface::new(isolate_state, &plugin_lib);
-        let op = dispatch_op_fn(&mut interface, control, zero_copy);
+        let op = dispatch_op_fn(&mut interface, zero_copy);
         match op {
           sync_op @ Op::Sync(..) => sync_op,
           Op::Async(fut) => {
diff --git a/cli/state.rs b/cli/state.rs
index 39bd8a565..5f3873510 100644
--- a/cli/state.rs
+++ b/cli/state.rs
@@ -65,7 +65,7 @@ impl State {
   pub fn stateful_json_op<D>(
     &self,
     dispatcher: D,
-  ) -> impl Fn(&mut deno_core::CoreIsolateState, &[u8], &mut [ZeroCopyBuf]) -> Op
+  ) -> impl Fn(&mut deno_core::CoreIsolateState, &mut [ZeroCopyBuf]) -> Op
   where
     D: Fn(&State, Value, &mut [ZeroCopyBuf]) -> Result<JsonOp, OpError>,
   {
@@ -76,7 +76,7 @@ impl State {
   pub fn stateful_json_op2<D>(
     &self,
     dispatcher: D,
-  ) -> impl Fn(&mut deno_core::CoreIsolateState, &[u8], &mut [ZeroCopyBuf]) -> Op
+  ) -> impl Fn(&mut deno_core::CoreIsolateState, &mut [ZeroCopyBuf]) -> Op
   where
     D: Fn(
       &mut deno_core::CoreIsolateState,
@@ -95,21 +95,21 @@ impl State {
   pub fn core_op<D>(
     &self,
     dispatcher: D,
-  ) -> impl Fn(&mut deno_core::CoreIsolateState, &[u8], &mut [ZeroCopyBuf]) -> Op
+  ) -> impl Fn(&mut deno_core::CoreIsolateState, &mut [ZeroCopyBuf]) -> Op
   where
-    D: Fn(&mut deno_core::CoreIsolateState, &[u8], &mut [ZeroCopyBuf]) -> Op,
+    D: Fn(&mut deno_core::CoreIsolateState, &mut [ZeroCopyBuf]) -> Op,
   {
     let state = self.clone();
 
     move |isolate_state: &mut deno_core::CoreIsolateState,
-          control: &[u8],
           zero_copy: &mut [ZeroCopyBuf]|
           -> Op {
-      let bytes_sent_control = control.len() as u64;
+      let bytes_sent_control =
+        zero_copy.get(0).map(|s| s.len()).unwrap_or(0) as u64;
       let bytes_sent_zero_copy =
-        zero_copy.iter().map(|b| b.len()).sum::<usize>() as u64;
+        zero_copy[1..].iter().map(|b| b.len()).sum::<usize>() as u64;
 
-      let op = dispatcher(isolate_state, control, zero_copy);
+      let op = dispatcher(isolate_state, zero_copy);
 
       match op {
         Op::Sync(buf) => {
@@ -155,7 +155,7 @@ impl State {
   pub fn stateful_minimal_op2<D>(
     &self,
     dispatcher: D,
-  ) -> impl Fn(&mut deno_core::CoreIsolateState, &[u8], &mut [ZeroCopyBuf]) -> Op
+  ) -> impl Fn(&mut deno_core::CoreIsolateState, &mut [ZeroCopyBuf]) -> Op
   where
     D: Fn(
       &mut deno_core::CoreIsolateState,
diff --git a/core/Cargo.toml b/core/Cargo.toml
index 6b73cc02a..038b81580 100644
--- a/core/Cargo.toml
+++ b/core/Cargo.toml
@@ -21,6 +21,7 @@ libc = "0.2.71"
 log = "0.4.8"
 rusty_v8 = "0.6.0"
 serde_json = "1.0.55"
+smallvec = "1.4.0"
 url = "2.1.1"
 
 [[example]]
diff --git a/core/bindings.rs b/core/bindings.rs
index 6407cb555..0d0a633a5 100644
--- a/core/bindings.rs
+++ b/core/bindings.rs
@@ -8,6 +8,7 @@ use crate::ZeroCopyBuf;
 use rusty_v8 as v8;
 use v8::MapFnTo;
 
+use smallvec::SmallVec;
 use std::cell::Cell;
 use std::convert::TryFrom;
 use std::option::Option;
@@ -388,24 +389,11 @@ fn send(
     }
   };
 
-  let control_backing_store: v8::SharedRef<v8::BackingStore>;
-  let control = match v8::Local::<v8::ArrayBufferView>::try_from(args.get(1)) {
-    Ok(view) => unsafe {
-      control_backing_store = view.buffer(scope).unwrap().get_backing_store();
-      get_backing_store_slice(
-        &control_backing_store,
-        view.byte_offset(),
-        view.byte_length(),
-      )
-    },
-    Err(_) => &[],
-  };
-
   let state_rc = CoreIsolate::state(scope);
   let mut state = state_rc.borrow_mut();
   assert!(!state.global_context.is_empty());
 
-  let mut buf_iter = (2..args.length()).map(|idx| {
+  let buf_iter = (1..args.length()).map(|idx| {
     v8::Local::<v8::ArrayBufferView>::try_from(args.get(idx))
       .map(|view| ZeroCopyBuf::new(scope, view))
       .map_err(|err| {
@@ -415,36 +403,15 @@ fn send(
       })
   });
 
-  let mut buf_one: ZeroCopyBuf;
-  let mut buf_vec: Vec<ZeroCopyBuf>;
-
-  // Collect all ArrayBufferView's
-  let buf_iter_result = match buf_iter.len() {
-    0 => Ok(&mut [][..]),
-    1 => match buf_iter.next().unwrap() {
-      Ok(buf) => {
-        buf_one = buf;
-        Ok(std::slice::from_mut(&mut buf_one))
+  // If response is empty then it's either async op or exception was thrown.
+  let maybe_response =
+    match buf_iter.collect::<Result<SmallVec<[ZeroCopyBuf; 2]>, _>>() {
+      Ok(mut bufs) => state.dispatch_op(scope, op_id, &mut bufs),
+      Err(exc) => {
+        scope.throw_exception(exc);
+        return;
       }
-      Err(err) => Err(err),
-    },
-    _ => match buf_iter.collect::<Result<Vec<_>, _>>() {
-      Ok(v) => {
-        buf_vec = v;
-        Ok(&mut buf_vec[..])
-      }
-      Err(err) => Err(err),
-    },
-  };
-
-  // If response is empty then it's either async op or exception was thrown
-  let maybe_response = match buf_iter_result {
-    Ok(bufs) => state.dispatch_op(scope, op_id, control, bufs),
-    Err(exc) => {
-      scope.throw_exception(exc);
-      return;
-    }
-  };
+    };
 
   if let Some(response) = maybe_response {
     // Synchronous response.
diff --git a/core/core_isolate.rs b/core/core_isolate.rs
index bb1807f62..ffe75c00c 100644
--- a/core/core_isolate.rs
+++ b/core/core_isolate.rs
@@ -350,7 +350,7 @@ impl CoreIsolate {
   /// Requires runtime to explicitly ask for op ids before using any of the ops.
   pub fn register_op<F>(&mut self, name: &str, op: F) -> OpId
   where
-    F: Fn(&mut CoreIsolateState, &[u8], &mut [ZeroCopyBuf]) -> Op + 'static,
+    F: Fn(&mut CoreIsolateState, &mut [ZeroCopyBuf]) -> Op + 'static,
   {
     let state_rc = Self::state(self);
     let mut state = state_rc.borrow_mut();
@@ -466,7 +466,7 @@ impl CoreIsolateState {
   /// Requires runtime to explicitly ask for op ids before using any of the ops.
   pub fn register_op<F>(&mut self, name: &str, op: F) -> OpId
   where
-    F: Fn(&mut CoreIsolateState, &[u8], &mut [ZeroCopyBuf]) -> Op + 'static,
+    F: Fn(&mut CoreIsolateState, &mut [ZeroCopyBuf]) -> Op + 'static,
   {
     self.op_registry.register(name, op)
   }
@@ -485,11 +485,10 @@ impl CoreIsolateState {
     &mut self,
     scope: &mut v8::HandleScope<'s>,
     op_id: OpId,
-    control_buf: &[u8],
     zero_copy_bufs: &mut [ZeroCopyBuf],
   ) -> Option<(OpId, Box<[u8]>)> {
     let op = if let Some(dispatcher) = self.op_registry.get(op_id) {
-      dispatcher(self, control_buf, zero_copy_bufs)
+      dispatcher(self, zero_copy_bufs)
     } else {
       let message =
         v8::String::new(scope, &format!("Unknown op id: {}", op_id)).unwrap();
@@ -704,20 +703,21 @@ pub mod tests {
     let mut isolate = CoreIsolate::new(StartupData::None, false);
 
     let dispatcher = move |_state: &mut CoreIsolateState,
-                           control: &[u8],
                            zero_copy: &mut [ZeroCopyBuf]|
           -> Op {
       dispatch_count_.fetch_add(1, Ordering::Relaxed);
       match mode {
         Mode::Async => {
-          assert_eq!(control.len(), 1);
-          assert_eq!(control[0], 42);
+          assert_eq!(zero_copy.len(), 1);
+          assert_eq!(zero_copy[0].len(), 1);
+          assert_eq!(zero_copy[0][0], 42);
           let buf = vec![43u8].into_boxed_slice();
           Op::Async(futures::future::ready(buf).boxed())
         }
         Mode::AsyncUnref => {
-          assert_eq!(control.len(), 1);
-          assert_eq!(control[0], 42);
+          assert_eq!(zero_copy.len(), 1);
+          assert_eq!(zero_copy[0].len(), 1);
+          assert_eq!(zero_copy[0][0], 42);
           let fut = async {
             // This future never finish.
             futures::future::pending::<()>().await;
@@ -726,8 +726,6 @@ pub mod tests {
           Op::AsyncUnref(fut.boxed())
         }
         Mode::AsyncZeroCopy(count) => {
-          assert_eq!(control.len(), 1);
-          assert_eq!(control[0], 24);
           assert_eq!(zero_copy.len(), count as usize);
           zero_copy.iter().enumerate().for_each(|(idx, buf)| {
             assert_eq!(buf.len(), 1);
@@ -738,13 +736,15 @@ pub mod tests {
           Op::Async(futures::future::ready(buf).boxed())
         }
         Mode::OverflowReqSync => {
-          assert_eq!(control.len(), 100 * 1024 * 1024);
+          assert_eq!(zero_copy.len(), 1);
+          assert_eq!(zero_copy[0].len(), 100 * 1024 * 1024);
           let buf = vec![43u8].into_boxed_slice();
           Op::Sync(buf)
         }
         Mode::OverflowResSync => {
-          assert_eq!(control.len(), 1);
-          assert_eq!(control[0], 42);
+          assert_eq!(zero_copy.len(), 1);
+          assert_eq!(zero_copy[0].len(), 1);
+          assert_eq!(zero_copy[0][0], 42);
           let mut vec = Vec::<u8>::new();
           vec.resize(100 * 1024 * 1024, 0);
           vec[0] = 99;
@@ -752,13 +752,15 @@ pub mod tests {
           Op::Sync(buf)
         }
         Mode::OverflowReqAsync => {
-          assert_eq!(control.len(), 100 * 1024 * 1024);
+          assert_eq!(zero_copy.len(), 1);
+          assert_eq!(zero_copy[0].len(), 100 * 1024 * 1024);
           let buf = vec![43u8].into_boxed_slice();
           Op::Async(futures::future::ready(buf).boxed())
         }
         Mode::OverflowResAsync => {
-          assert_eq!(control.len(), 1);
-          assert_eq!(control[0], 42);
+          assert_eq!(zero_copy.len(), 1);
+          assert_eq!(zero_copy[0].len(), 1);
+          assert_eq!(zero_copy[0][0], 42);
           let mut vec = Vec::<u8>::new();
           vec.resize(100 * 1024 * 1024, 0);
           vec[0] = 4;
@@ -807,37 +809,38 @@ pub mod tests {
     js_check(isolate.execute(
       "filename.js",
       r#"
-        let control = new Uint8Array([24]);
-        Deno.core.send(1, control);
+        Deno.core.send(1);
         "#,
     ));
     assert_eq!(dispatch_count.load(Ordering::Relaxed), 1);
   }
 
   #[test]
-  fn test_dispatch_one_zero_copy_buf() {
-    let (mut isolate, dispatch_count) = setup(Mode::AsyncZeroCopy(1));
+  fn test_dispatch_stack_zero_copy_bufs() {
+    let (mut isolate, dispatch_count) = setup(Mode::AsyncZeroCopy(2));
     js_check(isolate.execute(
       "filename.js",
       r#"
-        let control = new Uint8Array([24]);
-        let zero_copy = new Uint8Array([0]);
-        Deno.core.send(1, control, zero_copy);
+        let zero_copy_a = new Uint8Array([0]);
+        let zero_copy_b = new Uint8Array([1]);
+        Deno.core.send(1, zero_copy_a, zero_copy_b);
         "#,
     ));
     assert_eq!(dispatch_count.load(Ordering::Relaxed), 1);
   }
 
   #[test]
-  fn test_dispatch_two_zero_copy_bufs() {
-    let (mut isolate, dispatch_count) = setup(Mode::AsyncZeroCopy(2));
+  fn test_dispatch_heap_zero_copy_bufs() {
+    let (mut isolate, dispatch_count) = setup(Mode::AsyncZeroCopy(5));
     js_check(isolate.execute(
       "filename.js",
       r#"
-        let control = new Uint8Array([24]);
         let zero_copy_a = new Uint8Array([0]);
         let zero_copy_b = new Uint8Array([1]);
-        Deno.core.send(1, control, zero_copy_a, zero_copy_b);
+        let zero_copy_c = new Uint8Array([2]);
+        let zero_copy_d = new Uint8Array([3]);
+        let zero_copy_e = new Uint8Array([4]);
+        Deno.core.send(1, zero_copy_a, zero_copy_b, zero_copy_c, zero_copy_d, zero_copy_e);
         "#,
     ));
     assert_eq!(dispatch_count.load(Ordering::Relaxed), 1);
@@ -1120,7 +1123,7 @@ pub mod tests {
         r#"
           let thrown;
           try {
-            Deno.core.dispatch(100, []);
+            Deno.core.dispatch(100);
           } catch (e) {
             thrown = e;
           }
diff --git a/core/es_isolate.rs b/core/es_isolate.rs
index 5bb1a55c0..a59ba7e92 100644
--- a/core/es_isolate.rs
+++ b/core/es_isolate.rs
@@ -708,12 +708,12 @@ pub mod tests {
     let mut isolate = EsIsolate::new(loader, StartupData::None, false);
 
     let dispatcher = move |_state: &mut CoreIsolateState,
-                           control: &[u8],
-                           _zero_copy: &mut [ZeroCopyBuf]|
+                           zero_copy: &mut [ZeroCopyBuf]|
           -> Op {
       dispatch_count_.fetch_add(1, Ordering::Relaxed);
-      assert_eq!(control.len(), 1);
-      assert_eq!(control[0], 42);
+      assert_eq!(zero_copy.len(), 1);
+      assert_eq!(zero_copy[0].len(), 1);
+      assert_eq!(zero_copy[0][0], 42);
       let buf = vec![43u8, 0, 0, 0].into_boxed_slice();
       Op::Async(futures::future::ready(buf).boxed())
     };
diff --git a/core/examples/http_bench.rs b/core/examples/http_bench.rs
index 233864fac..92e69d215 100644
--- a/core/examples/http_bench.rs
+++ b/core/examples/http_bench.rs
@@ -117,18 +117,19 @@ impl Isolate {
   {
     let state = self.state.clone();
     let core_handler = move |_isolate_state: &mut CoreIsolateState,
-                             control_buf: &[u8],
                              zero_copy_bufs: &mut [ZeroCopyBuf]|
           -> Op {
+      assert!(!zero_copy_bufs.is_empty());
       let state = state.clone();
-      let record = Record::from(control_buf);
+      let record = Record::from(zero_copy_bufs[0].as_ref());
       let is_sync = record.promise_id == 0;
       assert!(is_sync);
 
-      let result: i32 = match handler(state, record.rid, zero_copy_bufs) {
-        Ok(r) => r as i32,
-        Err(_) => -1,
-      };
+      let result: i32 =
+        match handler(state, record.rid, &mut zero_copy_bufs[1..]) {
+          Ok(r) => r as i32,
+          Err(_) => -1,
+        };
       let buf = RecordBuf::from(Record { result, ..record })[..].into();
       Op::Sync(buf)
     };
@@ -147,15 +148,15 @@ impl Isolate {
   {
     let state = self.state.clone();
     let core_handler = move |_isolate_state: &mut CoreIsolateState,
-                             control_buf: &[u8],
                              zero_copy_bufs: &mut [ZeroCopyBuf]|
           -> Op {
+      assert!(!zero_copy_bufs.is_empty());
       let state = state.clone();
-      let record = Record::from(control_buf);
+      let record = Record::from(zero_copy_bufs[0].as_ref());
       let is_sync = record.promise_id == 0;
       assert!(!is_sync);
 
-      let mut zero_copy = zero_copy_bufs.to_vec();
+      let mut zero_copy = zero_copy_bufs[1..].to_vec();
       let fut = async move {
         let op = handler(state, record.rid, &mut zero_copy);
         let result = op
diff --git a/core/ops.rs b/core/ops.rs
index eb995df6e..65a0f325b 100644
--- a/core/ops.rs
+++ b/core/ops.rs
@@ -22,7 +22,7 @@ pub enum Op {
 
 /// Main type describing op
 pub type OpDispatcher =
-  dyn Fn(&mut CoreIsolateState, &[u8], &mut [ZeroCopyBuf]) -> Op + 'static;
+  dyn Fn(&mut CoreIsolateState, &mut [ZeroCopyBuf]) -> Op + 'static;
 
 #[derive(Default)]
 pub struct OpRegistry {
@@ -33,7 +33,7 @@ pub struct OpRegistry {
 impl OpRegistry {
   pub fn new() -> Self {
     let mut registry = Self::default();
-    let op_id = registry.register("ops", |state, _, _| {
+    let op_id = registry.register("ops", |state, _| {
       let buf = state.op_registry.json_map();
       Op::Sync(buf)
     });
@@ -43,7 +43,7 @@ impl OpRegistry {
 
   pub fn register<F>(&mut self, name: &str, op: F) -> OpId
   where
-    F: Fn(&mut CoreIsolateState, &[u8], &mut [ZeroCopyBuf]) -> Op + 'static,
+    F: Fn(&mut CoreIsolateState, &mut [ZeroCopyBuf]) -> Op + 'static,
   {
     let op_id = self.dispatchers.len() as u32;
 
@@ -81,7 +81,7 @@ fn test_op_registry() {
   let c = Arc::new(atomic::AtomicUsize::new(0));
   let c_ = c.clone();
 
-  let test_id = op_registry.register("test", move |_, _, _| {
+  let test_id = op_registry.register("test", move |_, _| {
     c_.fetch_add(1, atomic::Ordering::SeqCst);
     Op::Sync(Box::new([]))
   });
@@ -97,7 +97,7 @@ fn test_op_registry() {
   let dispatch = op_registry.get(test_id).unwrap();
   let state_rc = CoreIsolate::state(&isolate);
   let mut state = state_rc.borrow_mut();
-  let res = dispatch(&mut state, &[], &mut []);
+  let res = dispatch(&mut state, &mut []);
   if let Op::Sync(buf) = res {
     assert_eq!(buf.len(), 0);
   } else {
@@ -127,10 +127,10 @@ fn register_op_during_call() {
 
   let test_id = {
     let mut g = op_registry.lock().unwrap();
-    g.register("dynamic_register_op", move |_, _, _| {
+    g.register("dynamic_register_op", move |_, _| {
       let c__ = c_.clone();
       let mut g = op_registry_.lock().unwrap();
-      g.register("test", move |_, _, _| {
+      g.register("test", move |_, _| {
         c__.fetch_add(1, atomic::Ordering::SeqCst);
         Op::Sync(Box::new([]))
       });
@@ -148,7 +148,7 @@ fn register_op_during_call() {
   {
     let state_rc = CoreIsolate::state(&isolate);
     let mut state = state_rc.borrow_mut();
-    dispatcher1(&mut state, &[], &mut []);
+    dispatcher1(&mut state, &mut []);
   }
 
   let mut expected = HashMap::new();
@@ -166,7 +166,7 @@ fn register_op_during_call() {
   };
   let state_rc = CoreIsolate::state(&isolate);
   let mut state = state_rc.borrow_mut();
-  let res = dispatcher2(&mut state, &[], &mut []);
+  let res = dispatcher2(&mut state, &mut []);
   if let Op::Sync(buf) = res {
     assert_eq!(buf.len(), 0);
   } else {
diff --git a/core/plugin_api.rs b/core/plugin_api.rs
index 16f5d4a36..0cb9acaeb 100644
--- a/core/plugin_api.rs
+++ b/core/plugin_api.rs
@@ -15,7 +15,7 @@ pub use crate::ZeroCopyBuf;
 
 pub type InitFn = fn(&mut dyn Interface);
 
-pub type DispatchOpFn = fn(&mut dyn Interface, &[u8], &mut [ZeroCopyBuf]) -> Op;
+pub type DispatchOpFn = fn(&mut dyn Interface, &mut [ZeroCopyBuf]) -> Op;
 
 pub trait Interface {
   fn register_op(&mut self, name: &str, dispatcher: DispatchOpFn) -> OpId;
diff --git a/core/zero_copy_buf.rs b/core/zero_copy_buf.rs
index a458e12ff..a2625b8aa 100644
--- a/core/zero_copy_buf.rs
+++ b/core/zero_copy_buf.rs
@@ -6,8 +6,14 @@ use std::ops::DerefMut;
 /// A ZeroCopyBuf encapsulates a slice that's been borrowed from a JavaScript
 /// ArrayBuffer object. JavaScript objects can normally be garbage collected,
 /// but the existence of a ZeroCopyBuf inhibits this until it is dropped. It
-/// behaves much like an Arc<[u8]>, although a ZeroCopyBuf currently can't be
-/// cloned.
+/// behaves much like an Arc<[u8]>.
+///
+/// # Cloning
+/// Cloning a ZeroCopyBuf does not clone the contents of the buffer,
+/// it creates a new reference to that buffer.
+///
+/// To actually clone the contents of the buffer do
+/// `let copy = Vec::from(&*zero_copy_buf);`
 #[derive(Clone)]
 pub struct ZeroCopyBuf {
   backing_store: v8::SharedRef<v8::BackingStore>,
diff --git a/deno_typescript/lib.rs b/deno_typescript/lib.rs
index 54d9b1d3b..70d6d42d0 100644
--- a/deno_typescript/lib.rs
+++ b/deno_typescript/lib.rs
@@ -50,17 +50,16 @@ pub struct TSState {
 fn compiler_op<D>(
   ts_state: Arc<Mutex<TSState>>,
   dispatcher: D,
-) -> impl Fn(&mut CoreIsolateState, &[u8], &mut [ZeroCopyBuf]) -> Op
+) -> impl Fn(&mut CoreIsolateState, &mut [ZeroCopyBuf]) -> Op
 where
   D: Fn(&mut TSState, &[u8]) -> Op,
 {
   move |_state: &mut CoreIsolateState,
-        control: &[u8],
         zero_copy_bufs: &mut [ZeroCopyBuf]|
         -> Op {
-    assert!(zero_copy_bufs.is_empty()); // zero_copy_bufs unused in compiler.
+    assert_eq!(zero_copy_bufs.len(), 1, "Invalid number of arguments");
     let mut s = ts_state.lock().unwrap();
-    dispatcher(&mut s, control)
+    dispatcher(&mut s, &zero_copy_bufs[0])
   }
 }
 
@@ -338,16 +337,15 @@ pub fn trace_serializer() {
 /// CoreIsolate.
 pub fn op_fetch_asset<S: ::std::hash::BuildHasher>(
   custom_assets: HashMap<String, PathBuf, S>,
-) -> impl Fn(&mut CoreIsolateState, &[u8], &mut [ZeroCopyBuf]) -> Op {
+) -> impl Fn(&mut CoreIsolateState, &mut [ZeroCopyBuf]) -> Op {
   for (_, path) in custom_assets.iter() {
     println!("cargo:rerun-if-changed={}", path.display());
   }
   move |_state: &mut CoreIsolateState,
-        control: &[u8],
         zero_copy_bufs: &mut [ZeroCopyBuf]|
         -> Op {
-    assert!(zero_copy_bufs.is_empty()); // zero_copy_bufs unused in this op.
-    let name = std::str::from_utf8(control).unwrap();
+    assert_eq!(zero_copy_bufs.len(), 1, "Invalid number of arguments");
+    let name = std::str::from_utf8(&zero_copy_bufs[0]).unwrap();
 
     let asset_code = if let Some(source_code) = get_asset(name) {
       source_code.to_string()
diff --git a/test_plugin/src/lib.rs b/test_plugin/src/lib.rs
index 781bc4259..bb4c4d8ff 100644
--- a/test_plugin/src/lib.rs
+++ b/test_plugin/src/lib.rs
@@ -12,14 +12,12 @@ pub fn deno_plugin_init(interface: &mut dyn Interface) {
 
 fn op_test_sync(
   _interface: &mut dyn Interface,
-  data: &[u8],
   zero_copy: &mut [ZeroCopyBuf],
 ) -> Op {
-  let data_str = std::str::from_utf8(&data[..]).unwrap();
-  let zero_copy = zero_copy.to_vec();
   if !zero_copy.is_empty() {
-    println!("Hello from plugin. data: {}", data_str);
+    println!("Hello from plugin.");
   }
+  let zero_copy = zero_copy.to_vec();
   for (idx, buf) in zero_copy.iter().enumerate() {
     let buf_str = std::str::from_utf8(&buf[..]).unwrap();
     println!("zero_copy[{}]: {}", idx, buf_str);
@@ -31,14 +29,12 @@ fn op_test_sync(
 
 fn op_test_async(
   _interface: &mut dyn Interface,
-  data: &[u8],
   zero_copy: &mut [ZeroCopyBuf],
 ) -> Op {
-  let zero_copy = zero_copy.to_vec();
   if !zero_copy.is_empty() {
-    let data_str = std::str::from_utf8(&data[..]).unwrap().to_string();
-    println!("Hello from plugin. data: {}", data_str);
+    println!("Hello from plugin.");
   }
+  let zero_copy = zero_copy.to_vec();
   let fut = async move {
     for (idx, buf) in zero_copy.iter().enumerate() {
       let buf_str = std::str::from_utf8(&buf[..]).unwrap();
diff --git a/test_plugin/tests/integration_tests.rs b/test_plugin/tests/integration_tests.rs
index 53d1c2441..85374c217 100644
--- a/test_plugin/tests/integration_tests.rs
+++ b/test_plugin/tests/integration_tests.rs
@@ -36,7 +36,7 @@ fn basic() {
     println!("stderr {}", stderr);
   }
   assert!(output.status.success());
-  let expected = "Hello from plugin. data: test\nzero_copy[0]: test\nzero_copy[1]: 123\nzero_copy[2]: cba\nPlugin Sync Response: test\nHello from plugin. data: test\nzero_copy[0]: test\nzero_copy[1]: 123\nPlugin Async Response: test\n";
+  let expected = "Hello from plugin.\nzero_copy[0]: test\nzero_copy[1]: 123\nzero_copy[2]: cba\nPlugin Sync Response: test\nHello from plugin.\nzero_copy[0]: test\nzero_copy[1]: 123\nPlugin Async Response: test\n";
   assert_eq!(stdout, expected);
   assert_eq!(stderr, "");
 }
diff --git a/test_plugin/tests/test.js b/test_plugin/tests/test.js
index fbe58aeb8..d48394b4b 100644
--- a/test_plugin/tests/test.js
+++ b/test_plugin/tests/test.js
@@ -33,7 +33,6 @@ function runTestSync() {
   const response = Deno.core.dispatch(
     testSync,
     new Uint8Array([116, 101, 115, 116]),
-    new Uint8Array([116, 101, 115, 116]),
     new Uint8Array([49, 50, 51]),
     new Uint8Array([99, 98, 97])
   );
@@ -49,7 +48,6 @@ function runTestAsync() {
   const response = Deno.core.dispatch(
     testAsync,
     new Uint8Array([116, 101, 115, 116]),
-    new Uint8Array([116, 101, 115, 116]),
     new Uint8Array([49, 50, 51])
   );
 
@@ -61,7 +59,7 @@ function runTestAsync() {
 function runTestOpCount() {
   const start = Deno.metrics();
 
-  Deno.core.dispatch(testSync, new Uint8Array([116, 101, 115, 116]));
+  Deno.core.dispatch(testSync);
 
   const end = Deno.metrics();