[hardware wallet] sleeping -> pollling (#8018)

* Use polling, enable missing doc warnings & docs

* make try_connect_polling() a free function

hw/src/ledger.rs

@@ -21,8 +21,7 @@ use std::cmp::min;
 use std::fmt;
 use std::str::FromStr;
 use std::sync::{Arc, Weak};
-use std::time::Duration;
+use std::time::{Duration, Instant};
-use std::thread;
 
 use ethereum_types::{H256, Address};
 use ethkey::Signature;
@@ -353,11 +352,24 @@ impl Manager {
 			Err(Error::InvalidDevice)
 		}
 	}
+}
 
+// Try to connect to the device using polling in at most the time specified by the `timeout`
+fn try_connect_polling(ledger: Arc<Manager>, timeout: Duration) -> bool {
+	let start_time = Instant::now();
+	while start_time.elapsed() <= timeout {
+		if let Ok(_) = ledger.update_devices() {
+			return true
+		}
+	}
+	false
 }
 
 /// Ledger event handler
-/// A seperate thread is handling incoming events
+/// A seperate thread is hanedling incoming events
+///
+/// Note, that this run to completion and race-conditions can't occur but this can
+/// therefore starve other events for being process with a spinlock or similar
 pub struct EventHandler {
 	ledger: Weak<Manager>,
 }
@@ -371,21 +383,19 @@ impl EventHandler {
 
 impl libusb::Hotplug for EventHandler {
 	fn device_arrived(&mut self, device: libusb::Device) {
-		if let (Some(ledger), Ok(_)) = (self.ledger.upgrade(), Manager::is_valid_ledger(&device)) {
 		debug!(target: "hw", "Ledger arrived");
-			// Wait for the device to boot up
+		if let (Some(ledger), Ok(_)) = (self.ledger.upgrade(), Manager::is_valid_ledger(&device)) {
-			thread::sleep(Duration::from_millis(1000));
+			if try_connect_polling(ledger, Duration::from_millis(500)) != true {
-			if let Err(e) = ledger.update_devices() {
+				debug!(target: "hw", "Ledger connect timeout");
-				debug!(target: "hw", "Ledger connect error: {:?}", e);
 			}
 		}
 	}
 
 	fn device_left(&mut self, device: libusb::Device) {
-		if let (Some(ledger), Ok(_)) = (self.ledger.upgrade(), Manager::is_valid_ledger(&device)) {
 		debug!(target: "hw", "Ledger left");
-			if let Err(e) = ledger.update_devices() {
+		if let (Some(ledger), Ok(_)) = (self.ledger.upgrade(), Manager::is_valid_ledger(&device)) {
-				debug!(target: "hw", "Ledger disconnect error: {:?}", e);
+			if try_connect_polling(ledger, Duration::from_millis(500)) != true {
+				debug!(target: "hw", "Ledger disconnect timeout");
 			}
 		}
 	}

hw/src/lib.rs

@@ -16,6 +16,8 @@
 
 //! Hardware wallet management.
 
+#![warn(missing_docs)]
+
 extern crate ethereum_types;
 extern crate ethkey;
 extern crate hidapi;
@@ -61,12 +63,19 @@ pub enum Error {
 /// or less a duplicate of ethcore::transaction::Transaction, but we can't
 /// import ethcore here as that would be a circular dependency.
 pub struct TransactionInfo {
+	/// Nonce
 	pub nonce: U256,
+	/// Gas price
 	pub gas_price: U256,
+	/// Gas limit
 	pub gas_limit: U256,
+	/// Receiver
 	pub to: Option<Address>,
+	/// Value
 	pub value: U256,
+	/// Data
 	pub data: Vec<u8>,
+	/// Chain ID
 	pub chain_id: Option<u64>,
 }
 

hw/src/trezor.rs

@@ -24,11 +24,9 @@ use super::{WalletInfo, TransactionInfo, KeyPath};
 use std::cmp::{min, max};
 use std::fmt;
 use std::sync::{Arc, Weak};
-use std::time::Duration;
+use std::time::{Duration, Instant};
-use std::thread;
 
 use ethereum_types::{U256, H256, Address};
-
 use ethkey::Signature;
 use hidapi;
 use libusb;
@@ -402,14 +400,28 @@ impl Manager {
 	}
 }
 
+// Try to connect to the device using polling in at most the time specified by the `timeout`
+fn try_connect_polling(trezor: Arc<Manager>, duration: Duration) -> bool {
+	let start_time = Instant::now();
+	while start_time.elapsed() <= duration {
+		if let Ok(_) = trezor.update_devices() {
+			return true
+		}
+	}
+	false
+}
+
 /// Trezor event handler
 /// A separate thread is handeling incoming events
+///
+/// Note, that this run to completion and race-conditions can't occur but this can
+/// therefore starve other events for being process with a spinlock or similar
 pub struct EventHandler {
 	trezor: Weak<Manager>,
 }
 
 impl EventHandler {
-	// Trezor event handler constructor
+	/// Trezor event handler constructor
 	pub fn new(trezor: Weak<Manager>) -> Self {
 		Self { trezor: trezor }
 	}
@@ -419,20 +431,17 @@ impl libusb::Hotplug for EventHandler {
 	fn device_arrived(&mut self, _device: libusb::Device) {
 		debug!(target: "hw", "Trezor V1 arrived");
 		if let Some(trezor) = self.trezor.upgrade() {
-			// Wait for the device to boot up
+			if try_connect_polling(trezor, Duration::from_millis(500)) != true {
-			thread::sleep(Duration::from_millis(1000));
+				debug!(target: "hw", "Ledger connect timeout");
-			if let Err(e) = trezor.update_devices() {
-				debug!(target: "hw", "Trezor V1 connect error: {:?}", e);
 			}
-
 		}
 	}
 
 	fn device_left(&mut self, _device: libusb::Device) {
 		debug!(target: "hw", "Trezor V1 left");
 		if let Some(trezor) = self.trezor.upgrade() {
-			if let Err(e) = trezor.update_devices() {
+			if try_connect_polling(trezor, Duration::from_millis(500)) != true {
-				debug!(target: "hw", "Trezor V1 disconnect error: {:?}", e);
+				debug!(target: "hw", "Ledger disconnect timeout");
 			}
 		}
 	}