fix: align plugin api with Extension (#10427)

core/extensions.rs

@@ -24,15 +24,15 @@ impl Extension {
 
   /// returns JS source code to be loaded into the isolate (either at snapshotting,
   /// or at startup).  as a vector of a tuple of the file name, and the source code.
-  pub(crate) fn init_js(&self) -> Vec<SourcePair> {
+  pub fn init_js(&self) -> Vec<SourcePair> {
     match &self.js_files {
       Some(files) => files.clone(),
       None => vec![],
     }
   }
 
   /// Called at JsRuntime startup to initialize ops in the isolate.
-  pub(crate) fn init_ops(&mut self) -> Option<Vec<OpPair>> {
+  pub fn init_ops(&mut self) -> Option<Vec<OpPair>> {
     // TODO(@AaronO): maybe make op registration idempotent
     if self.initialized {
       panic!("init_ops called twice: not idempotent or correct");
@@ -43,15 +43,15 @@ impl Extension {
   }
 
   /// Allows setting up the initial op-state of an isolate at startup.
-  pub(crate) fn init_state(&self, state: &mut OpState) -> Result<(), AnyError> {
+  pub fn init_state(&self, state: &mut OpState) -> Result<(), AnyError> {
     match &self.opstate_fn {
       Some(ofn) => ofn(state),
       None => Ok(()),
     }
   }
 
   /// init_middleware lets us middleware op registrations, it's called before init_ops
-  pub(crate) fn init_middleware(&mut self) -> Option<Box<OpMiddlewareFn>> {
+  pub fn init_middleware(&mut self) -> Option<Box<OpMiddlewareFn>> {
     self.middleware_fn.take()
   }
 }

core/lib.rs

@@ -12,7 +12,6 @@ mod normalize_path;
 mod ops;
 mod ops_builtin;
 mod ops_json;
-pub mod plugin_api;
 mod resources;
 mod runtime;
 

runtime/js/40_plugins.js

@@ -5,7 +5,9 @@
   const core = window.Deno.core;
 
   function openPlugin(filename) {
-    return core.opSync("op_open_plugin", filename);
+    const rid = core.opSync("op_open_plugin", filename);
+    core.syncOpsCache();
+    return rid;
   }
 
   window.__bootstrap.plugins = {

runtime/ops/plugin.rs

@@ -1,27 +1,27 @@
 // Copyright 2018-2021 the Deno authors. All rights reserved. MIT license.
-use crate::metrics::metrics_op;
 use crate::permissions::Permissions;
 use deno_core::error::AnyError;
-use deno_core::futures::prelude::*;
 use deno_core::op_sync;
-use deno_core::plugin_api;
 use deno_core::Extension;
-use deno_core::Op;
-use deno_core::OpAsyncFuture;
-use deno_core::OpFn;
-use deno_core::OpId;
 use deno_core::OpState;
 use deno_core::Resource;
 use deno_core::ResourceId;
 use deno_core::ZeroCopyBuf;
 use dlopen::symbor::Library;
 use log::debug;
 use std::borrow::Cow;
+use std::mem;
 use std::path::PathBuf;
-use std::pin::Pin;
 use std::rc::Rc;
-use std::task::Context;
-use std::task::Poll;
+
+/// A default `init` function for plugins which mimics the way the internal
+/// extensions are initalized. Plugins currently do not support all extension
+/// features and are most likely not going to in the future. Currently only
+/// `init_state` and `init_ops` are supported while `init_middleware` and `init_js`
+/// are not. Currently the `PluginResource` does not support being closed due to
+/// certain risks in unloading the dynamic library without unloading dependent
+/// functions and resources.
+pub type InitFn = fn() -> Extension;
 
 pub fn init() -> Extension {
   Extension::builder()
@@ -44,111 +44,44 @@ pub fn op_open_plugin(
   let plugin_lib = Library::open(filename).map(Rc::new)?;
   let plugin_resource = PluginResource::new(&plugin_lib);
 
-  let rid;
-  let deno_plugin_init;
-  {
-    rid = state.resource_table.add(plugin_resource);
-    deno_plugin_init = *unsafe {
-      state
-        .resource_table
-        .get::<PluginResource>(rid)
-        .unwrap()
-        .lib
-        .symbol::<plugin_api::InitFn>("deno_plugin_init")
-        .unwrap()
-    };
-  }
-
-  let mut interface = PluginInterface::new(state, &plugin_lib);
-  deno_plugin_init(&mut interface);
+  // Forgets the plugin_lib value to prevent segfaults when the process exits
+  mem::forget(plugin_lib);
 
-  Ok(rid)
-}
-
-struct PluginResource {
-  lib: Rc<Library>,
-}
+  let init = *unsafe { plugin_resource.0.symbol::<InitFn>("init") }?;
+  let rid = state.resource_table.add(plugin_resource);
+  let mut extension = init();
 
-impl Resource for PluginResource {
-  fn name(&self) -> Cow<str> {
-    "plugin".into()
+  if !extension.init_js().is_empty() {
+    panic!("Plugins do not support loading js");
   }
-}
 
-impl PluginResource {
-  fn new(lib: &Rc<Library>) -> Self {
-    Self { lib: lib.clone() }
+  if extension.init_middleware().is_some() {
+    panic!("Plugins do not support middleware");
   }
-}
-
-struct PluginInterface<'a> {
-  state: &'a mut OpState,
-  plugin_lib: &'a Rc<Library>,
-}
 
-impl<'a> PluginInterface<'a> {
-  fn new(state: &'a mut OpState, plugin_lib: &'a Rc<Library>) -> Self {
-    Self { state, plugin_lib }
+  extension.init_state(state)?;
+  let ops = extension.init_ops().unwrap_or_default();
+  for (name, opfn) in ops {
+    state.op_table.register_op(name, opfn);
   }
-}
 
-impl<'a> plugin_api::Interface for PluginInterface<'a> {
-  /// Does the same as `core::Isolate::register_op()`, but additionally makes
-  /// the registered op dispatcher, as well as the op futures created by it,
-  /// keep reference to the plugin `Library` object, so that the plugin doesn't
-  /// get unloaded before all its op registrations and the futures created by
-  /// them are dropped.
-  fn register_op(
-    &mut self,
-    name: &str,
-    dispatch_op_fn: plugin_api::DispatchOpFn,
-  ) -> OpId {
-    let plugin_lib = self.plugin_lib.clone();
-    let plugin_op_fn: Box<OpFn> = Box::new(move |state_rc, payload| {
-      let mut state = state_rc.borrow_mut();
-      let mut interface = PluginInterface::new(&mut state, &plugin_lib);
-      let (_, buf): ((), Option<ZeroCopyBuf>) = payload.deserialize().unwrap();
-      let op = dispatch_op_fn(&mut interface, buf);
-      match op {
-        sync_op @ Op::Sync(..) => sync_op,
-        Op::Async(fut) => Op::Async(PluginOpAsyncFuture::new(&plugin_lib, fut)),
-        Op::AsyncUnref(fut) => {
-          Op::AsyncUnref(PluginOpAsyncFuture::new(&plugin_lib, fut))
-        }
-        _ => unreachable!(),
-      }
-    });
-    self.state.op_table.register_op(
-      name,
-      metrics_op(Box::leak(Box::new(name.to_string())), plugin_op_fn),
-    )
-  }
+  Ok(rid)
 }
 
-struct PluginOpAsyncFuture {
-  fut: Option<OpAsyncFuture>,
-  _plugin_lib: Rc<Library>,
-}
+struct PluginResource(Rc<Library>);
 
-impl PluginOpAsyncFuture {
-  fn new(plugin_lib: &Rc<Library>, fut: OpAsyncFuture) -> Pin<Box<Self>> {
-    let wrapped_fut = Self {
-      fut: Some(fut),
-      _plugin_lib: plugin_lib.clone(),
-    };
-    Box::pin(wrapped_fut)
+impl Resource for PluginResource {
+  fn name(&self) -> Cow<str> {
+    "plugin".into()
   }
-}
 
-impl Future for PluginOpAsyncFuture {
-  type Output = <OpAsyncFuture as Future>::Output;
-  fn poll(mut self: Pin<&mut Self>, ctx: &mut Context) -> Poll<Self::Output> {
-    self.fut.as_mut().unwrap().poll_unpin(ctx)
+  fn close(self: Rc<Self>) {
+    unimplemented!();
   }
 }
 
-impl Drop for PluginOpAsyncFuture {
-  fn drop(&mut self) {
-    self.fut.take();
+impl PluginResource {
+  fn new(lib: &Rc<Library>) -> Self {
+    Self(lib.clone())
   }
 }