From 7d39d4e2e89c4f8e8fa2e7db5a275a112807313c Mon Sep 17 00:00:00 2001
From: Julien Cretin <cretin@google.com>
Date: Thu, 3 Mar 2022 10:10:56 +0100
Subject: [PATCH] Create a tock environment

---
 src/env/mod.rs  |  1 +
 src/env/tock.rs | 43 +++++++++++++++++++++++++++++++++++++++++++
 src/main.rs     | 33 ++-------------------------------
 3 files changed, 46 insertions(+), 31 deletions(-)
 create mode 100644 src/env/tock.rs

diff --git a/src/env/mod.rs b/src/env/mod.rs
index c66bd4f..04f849c 100644
--- a/src/env/mod.rs
+++ b/src/env/mod.rs
@@ -4,6 +4,7 @@ use crypto::rng256::Rng256;
 
 #[cfg(feature = "std")]
 pub mod test;
+pub mod tock;
 
 pub trait UserPresence {
     /// Blocks for user presence.
diff --git a/src/env/tock.rs b/src/env/tock.rs
new file mode 100644
index 0000000..29f8ed3
--- /dev/null
+++ b/src/env/tock.rs
@@ -0,0 +1,43 @@
+use crypto::rng256::TockRng256;
+
+use crate::ctap::hid::ChannelID;
+use crate::ctap::status_code::Ctap2StatusCode;
+use crate::env::{Env, UserPresence};
+
+pub struct TockEnv<CheckUserPresence: Fn(ChannelID) -> Result<(), Ctap2StatusCode>> {
+    rng: TockRng256,
+    check_user_presence: CheckUserPresence,
+}
+
+impl<CheckUserPresence: Fn(ChannelID) -> Result<(), Ctap2StatusCode>> TockEnv<CheckUserPresence> {
+    pub fn new(check_user_presence: CheckUserPresence) -> Self {
+        let rng = TockRng256 {};
+        TockEnv {
+            rng,
+            check_user_presence,
+        }
+    }
+}
+
+impl<CheckUserPresence: Fn(ChannelID) -> Result<(), Ctap2StatusCode>> UserPresence
+    for TockEnv<CheckUserPresence>
+{
+    fn check(&self, cid: ChannelID) -> Result<(), Ctap2StatusCode> {
+        (self.check_user_presence)(cid)
+    }
+}
+
+impl<CheckUserPresence: Fn(ChannelID) -> Result<(), Ctap2StatusCode>> Env
+    for TockEnv<CheckUserPresence>
+{
+    type Rng = TockRng256;
+    type UserPresence = Self;
+
+    fn rng(&mut self) -> &mut Self::Rng {
+        &mut self.rng
+    }
+
+    fn user_presence(&mut self) -> &mut Self::UserPresence {
+        self
+    }
+}
diff --git a/src/main.rs b/src/main.rs
index 4332fe3..4e49a65 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -24,10 +24,9 @@ extern crate lang_items;
 use core::cell::Cell;
 #[cfg(feature = "debug_ctap")]
 use core::fmt::Write;
-use crypto::rng256::TockRng256;
 use ctap2::ctap::hid::{ChannelID, CtapHid, KeepaliveStatus, ProcessedPacket};
 use ctap2::ctap::status_code::Ctap2StatusCode;
-use ctap2::env;
+use ctap2::env::tock::TockEnv;
 use libtock_core::result::{CommandError, EALREADY};
 use libtock_drivers::buttons;
 use libtock_drivers::buttons::ButtonState;
@@ -49,31 +48,6 @@ const KEEPALIVE_DELAY_MS: isize = 100;
 const KEEPALIVE_DELAY: Duration<isize> = Duration::from_ms(KEEPALIVE_DELAY_MS);
 const SEND_TIMEOUT: Duration<isize> = Duration::from_ms(1000);
 
-struct TockEnv {
-    rng: TockRng256,
-    user_presence: UserPresence,
-}
-
-struct UserPresence;
-impl env::UserPresence for UserPresence {
-    fn check(&self, cid: ChannelID) -> Result<(), Ctap2StatusCode> {
-        check_user_presence(cid)
-    }
-}
-
-impl env::Env for TockEnv {
-    type Rng = TockRng256;
-    type UserPresence = UserPresence;
-
-    fn rng(&mut self) -> &mut Self::Rng {
-        &mut self.rng
-    }
-
-    fn user_presence(&mut self) -> &mut Self::UserPresence {
-        &mut self.user_presence
-    }
-}
-
 fn main() {
     // Setup the timer with a dummy callback (we only care about reading the current time, but the
     // API forces us to set an alarm callback too).
@@ -86,10 +60,7 @@ fn main() {
     }
 
     let boot_time = timer.get_current_clock().flex_unwrap();
-    let env = TockEnv {
-        rng: TockRng256 {},
-        user_presence: UserPresence,
-    };
+    let env = TockEnv::new(check_user_presence);
     let mut ctap = ctap2::Ctap::new(env, boot_time);
 
     let mut led_counter = 0;