From 2768925ec689e59025f94d64eafd25f281170b23 Mon Sep 17 00:00:00 2001
From: Ian Douglas Scott <idscott@system76.com>
Date: Fri, 19 Feb 2021 07:41:25 -0800
Subject: [PATCH] tool: Support downcasting generic `Ec`

Removes the `impl Access for &mut dyn Access` I added earlier. But that
hasn't proven too useful.
---
 tool/Cargo.lock        |  7 +++++++
 tool/Cargo.toml        |  3 ++-
 tool/src/access/mod.rs | 15 ++++-----------
 tool/src/ec.rs         |  8 --------
 4 files changed, 13 insertions(+), 20 deletions(-)

diff --git a/tool/Cargo.lock b/tool/Cargo.lock
index 166e70d..e20fced 100644
--- a/tool/Cargo.lock
+++ b/tool/Cargo.lock
@@ -42,6 +42,11 @@ dependencies = [
  "vec_map 0.8.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "downcast-rs"
+version = "1.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "hermit-abi"
 version = "0.1.18"
@@ -85,6 +90,7 @@ name = "system76_ectool"
 version = "0.2.3"
 dependencies = [
  "clap 2.33.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "downcast-rs 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "hidapi 1.2.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.2.81 (registry+https://github.com/rust-lang/crates.io-index)",
  "redox_hwio 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -133,6 +139,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum bitflags 1.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "cf1de2fe8c75bc145a2f577add951f8134889b4795d47466a54a5c846d691693"
 "checksum cc 1.0.66 (registry+https://github.com/rust-lang/crates.io-index)" = "4c0496836a84f8d0495758516b8621a622beb77c0fed418570e50764093ced48"
 "checksum clap 2.33.3 (registry+https://github.com/rust-lang/crates.io-index)" = "37e58ac78573c40708d45522f0d80fa2f01cc4f9b4e2bf749807255454312002"
+"checksum downcast-rs 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "9ea835d29036a4087793836fa931b08837ad5e957da9e23886b29586fb9b6650"
 "checksum hermit-abi 0.1.18 (registry+https://github.com/rust-lang/crates.io-index)" = "322f4de77956e22ed0e5032c359a0f1273f1f7f0d79bfa3b8ffbc730d7fbcc5c"
 "checksum hidapi 1.2.5 (registry+https://github.com/rust-lang/crates.io-index)" = "76c352a18370f7e7e47bcbfcbdc5432b8c80c705b5d751a25232c659fcf5c775"
 "checksum libc 0.2.81 (registry+https://github.com/rust-lang/crates.io-index)" = "1482821306169ec4d07f6aca392a4681f66c75c9918aa49641a2595db64053cb"
diff --git a/tool/Cargo.toml b/tool/Cargo.toml
index d4f333b..214b04d 100644
--- a/tool/Cargo.toml
+++ b/tool/Cargo.toml
@@ -20,10 +20,11 @@ clap = "2"
 libc = { version = "0.2", optional = true }
 hidapi = { version = "1.2", default-features = false, features = ["linux-static-hidraw"], optional = true }
 redox_hwio = { version = "0.1.3", optional = true }
+downcast-rs = { version = "1.2.0", default-features = false }
 
 [features]
 default = ["std", "hidapi"]
-std = ["libc"]
+std = ["libc", "downcast-rs/std"]
 
 [package.metadata.docs.rs]
 all-features = true
diff --git a/tool/src/access/mod.rs b/tool/src/access/mod.rs
index 297ea3c..be12207 100644
--- a/tool/src/access/mod.rs
+++ b/tool/src/access/mod.rs
@@ -1,4 +1,5 @@
 use crate::Error;
+use downcast_rs::Downcast;
 
 #[cfg(feature = "hidapi")]
 pub use self::hid::AccessHid;
@@ -17,7 +18,7 @@ pub use self::lpc::*;
 mod lpc;
 
 /// Access method for running an EC command
-pub trait Access {
+pub trait Access: Downcast {
     /// Sends a command using the access method. Only internal use is recommended
     unsafe fn command(&mut self, cmd: u8, data: &mut [u8]) -> Result<u8, Error>;
 
@@ -31,16 +32,6 @@ pub trait Access {
     }
 }
 
-impl Access for &mut dyn Access {
-    unsafe fn command(&mut self, cmd: u8, data: &mut [u8]) -> Result<u8, Error> {
-        (**self).command(cmd, data)
-    }
-
-    fn data_size(&self) -> usize {
-        (**self).data_size()
-    }
-}
-
 impl Access for Box<dyn Access> {
     unsafe fn command(&mut self, cmd: u8, data: &mut [u8]) -> Result<u8, Error> {
         (**self).command(cmd, data)
@@ -50,3 +41,5 @@ impl Access for Box<dyn Access> {
         (**self).data_size()
     }
 }
+
+downcast_rs::impl_downcast!(Access);
diff --git a/tool/src/ec.rs b/tool/src/ec.rs
index aed8c77..f22a2f4 100644
--- a/tool/src/ec.rs
+++ b/tool/src/ec.rs
@@ -245,14 +245,6 @@ impl<A: Access> Ec<A> {
         self.command(Cmd::LedSetColor, &mut data)
     }
 
-    pub fn as_dyn(&mut self) -> Ec<&mut dyn Access> {
-        Ec {
-            access: &mut self.access,
-            version: self.version,
-
-        }
-    }
-
     pub fn into_dyn(self) -> Ec<Box<dyn Access>>
     where A: 'static {
         Ec {