From cf91550c65a0a1fb0cdd6bad714432ae8b786011 Mon Sep 17 00:00:00 2001
From: Scott Olson <scott@solson.me>
Date: Tue, 15 Sep 2020 03:33:18 +0100
Subject: refactor: Remove dependency on downcast_rs. (#7475)

We don't seem to use downcast_rs in any essential way. We can just use
the standard library `Any` directly.
---
 core/Cargo.toml   |  1 -
 core/lib.rs       |  2 --
 core/resources.rs | 34 +++++++++-------------------------
 3 files changed, 9 insertions(+), 28 deletions(-)

(limited to 'core')

diff --git a/core/Cargo.toml b/core/Cargo.toml
index d9b1243fc..f279accef 100644
--- a/core/Cargo.toml
+++ b/core/Cargo.toml
@@ -14,7 +14,6 @@ path = "lib.rs"
 
 [dependencies]
 anyhow = "1.0.32"
-downcast-rs = "1.2.0"
 futures = "0.3.5"
 indexmap = "1.6.0"
 lazy_static = "1.4.0"
diff --git a/core/lib.rs b/core/lib.rs
index ba7fdcd21..73d0da071 100644
--- a/core/lib.rs
+++ b/core/lib.rs
@@ -1,7 +1,5 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
 
-#[macro_use]
-extern crate downcast_rs;
 extern crate futures;
 #[macro_use]
 extern crate lazy_static;
diff --git a/core/resources.rs b/core/resources.rs
index 7a42a68a9..51d3260dc 100644
--- a/core/resources.rs
+++ b/core/resources.rs
@@ -6,7 +6,6 @@
 // Resources may or may not correspond to a real operating system file
 // descriptor (hence the different name).
 
-use downcast_rs::Downcast;
 use std::any::Any;
 use std::collections::HashMap;
 
@@ -16,7 +15,7 @@ pub type ResourceId = u32;
 
 /// These store Deno's file descriptors. These are not necessarily the operating
 /// system ones.
-type ResourceMap = HashMap<ResourceId, (String, Box<dyn Resource>)>;
+type ResourceMap = HashMap<ResourceId, (String, Box<dyn Any>)>;
 
 #[derive(Default)]
 pub struct ResourceTable {
@@ -29,20 +28,14 @@ impl ResourceTable {
     self.map.contains_key(&rid)
   }
 
-  pub fn get<T: Resource>(&self, rid: ResourceId) -> Option<&T> {
-    if let Some((_name, resource)) = self.map.get(&rid) {
-      return resource.downcast_ref::<T>();
-    }
-
-    None
+  pub fn get<T: Any>(&self, rid: ResourceId) -> Option<&T> {
+    let (_, resource) = self.map.get(&rid)?;
+    resource.downcast_ref::<T>()
   }
 
-  pub fn get_mut<T: Resource>(&mut self, rid: ResourceId) -> Option<&mut T> {
-    if let Some((_name, resource)) = self.map.get_mut(&rid) {
-      return resource.downcast_mut::<T>();
-    }
-
-    None
+  pub fn get_mut<T: Any>(&mut self, rid: ResourceId) -> Option<&mut T> {
+    let (_, resource) = self.map.get_mut(&rid)?;
+    resource.downcast_mut::<T>()
   }
 
   // TODO: resource id allocation should probably be randomized for security.
@@ -52,7 +45,7 @@ impl ResourceTable {
     next_rid as ResourceId
   }
 
-  pub fn add(&mut self, name: &str, resource: Box<dyn Resource>) -> ResourceId {
+  pub fn add(&mut self, name: &str, resource: Box<dyn Any>) -> ResourceId {
     let rid = self.next_rid();
     let r = self.map.insert(rid, (name.to_string(), resource));
     assert!(r.is_none());
@@ -73,7 +66,7 @@ impl ResourceTable {
     self.map.remove(&rid).map(|(_name, _resource)| ())
   }
 
-  pub fn remove<T: Resource>(&mut self, rid: ResourceId) -> Option<Box<T>> {
+  pub fn remove<T: Any>(&mut self, rid: ResourceId) -> Option<Box<T>> {
     if let Some((_name, resource)) = self.map.remove(&rid) {
       let res = match resource.downcast::<T>() {
         Ok(res) => Some(res),
@@ -85,15 +78,6 @@ impl ResourceTable {
   }
 }
 
-/// Abstract type representing resource in Deno.
-///
-/// The only thing it does is implementing `Downcast` trait
-/// that allows to cast resource to concrete type in `TableResource::get`
-/// and `TableResource::get_mut` methods.
-pub trait Resource: Downcast + Any {}
-impl<T> Resource for T where T: Downcast + Any {}
-impl_downcast!(Resource);
-
 #[cfg(test)]
 mod tests {
   use super::*;
-- 
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