fix(extract timestamp_checked_add as lib) (#10383)

* fix(extract `timestamp_checked_add` as lib)

* fix(whisper types): remove unused `EmptyTopics`

* fix(time-lib): feature-flag to use time-lib or std

This commit adds conditional compilation checks that falls back to `our time-lib` when
`time_checked_add` is not available in the standard library

Note, `time_checked_add` covers both `checked_add` and `checked_sub`

* fix(grumble): use cfg_attr to define rustc feature

whisper/Cargo.toml

@@ -24,6 +24,7 @@ serde_json = "1.0"
 slab = "0.3"
 smallvec = "0.6"
 tiny-keccak = "1.4"
+time-utils = { path = "../util/time-utils" }
 
 jsonrpc-core = "10.0.1"
 jsonrpc-derive = "10.0.2"

whisper/src/lib.rs

@@ -17,6 +17,8 @@
 //! Whisper P2P messaging system as a DevP2P subprotocol, with RPC and Rust
 //! interface.
 
+#![cfg_attr(feature = "time_checked_add", feature(time_checked_add))]
+
 extern crate byteorder;
 extern crate parity_crypto as crypto;
 extern crate ethcore_network as network;
@@ -46,6 +48,9 @@ extern crate log;
 #[macro_use]
 extern crate serde_derive;
 
+#[cfg(not(time_checked_add))]
+extern crate time_utils;
+
 #[cfg(test)]
 extern crate serde_json;
 

whisper/src/message.rs

@@ -24,6 +24,9 @@ use rlp::{self, DecoderError, RlpStream, Rlp};
 use smallvec::SmallVec;
 use tiny_keccak::{keccak256, Keccak};
 
+#[cfg(not(time_checked_add))]
+use time_utils::CheckedSystemTime;
+
 /// Work-factor proved. Takes 3 parameters: size of message, time to live,
 /// and hash.
 ///
@@ -117,6 +120,7 @@ pub enum Error {
 	EmptyTopics,
 	LivesTooLong,
 	IssuedInFuture,
+	TimestampOverflow,
 	ZeroTTL,
 }
 
@@ -133,6 +137,7 @@ impl fmt::Display for Error {
 			Error::LivesTooLong => write!(f, "Message claims to be issued before the unix epoch."),
 			Error::IssuedInFuture => write!(f, "Message issued in future."),
 			Error::ZeroTTL => write!(f, "Message live for zero time."),
+			Error::TimestampOverflow => write!(f, "Timestamp overflow"),
 			Error::EmptyTopics => write!(f, "Message has no topics."),
 		}
 	}
@@ -226,10 +231,6 @@ impl rlp::Decodable for Envelope {
 	}
 }
 
-/// Error indicating no topics.
-#[derive(Debug, Copy, Clone)]
-pub struct EmptyTopics;
-
 /// Message creation parameters.
 /// Pass this to `Message::create` to make a message.
 pub struct CreateParams {
@@ -255,11 +256,11 @@ pub struct Message {
 impl Message {
 	/// Create a message from creation parameters.
 	/// Panics if TTL is 0.
-	pub fn create(params: CreateParams) -> Result<Self, EmptyTopics> {
+	pub fn create(params: CreateParams) -> Result<Self, Error> {
 		use byteorder::{BigEndian, ByteOrder};
 		use rand::{Rng, SeedableRng, XorShiftRng};
 
-		if params.topics.is_empty() { return Err(EmptyTopics) }
+		if params.topics.is_empty() { return Err(Error::EmptyTopics) }
 
 		let mut rng = {
 			let mut thread_rng = ::rand::thread_rng();
@@ -270,7 +271,8 @@ impl Message {
 		assert!(params.ttl > 0);
 
 		let expiry = {
-			let after_mining = SystemTime::now() + Duration::from_millis(params.work);
+			let after_mining = SystemTime::now().checked_sub(Duration::from_millis(params.work))
+				.ok_or(Error::TimestampOverflow)?;
 			let since_epoch = after_mining.duration_since(time::UNIX_EPOCH)
 				.expect("time after now is after unix epoch; qed");
 
@@ -357,7 +359,10 @@ impl Message {
 			(envelope.expiry - envelope.ttl).saturating_sub(LEEWAY_SECONDS)
 		);
 
-		if time::UNIX_EPOCH + issue_time_adjusted > now {
+		let issue_time_adjusted = time::UNIX_EPOCH.checked_add(issue_time_adjusted)
+			.ok_or(Error::TimestampOverflow)?;
+
+		if issue_time_adjusted > now {
 			return Err(Error::IssuedInFuture);
 		}
 
@@ -400,8 +405,8 @@ impl Message {
 	}
 
 	/// Get the expiry time.
-	pub fn expiry(&self) -> SystemTime {
-		time::UNIX_EPOCH + Duration::from_secs(self.envelope.expiry)
+	pub fn expiry(&self) -> Option<SystemTime> {
+		time::UNIX_EPOCH.checked_add(Duration::from_secs(self.envelope.expiry))
 	}
 
 	/// Get the topics.

whisper/src/net/mod.rs

@@ -223,7 +223,10 @@ impl Messages {
 			}
 		}
 
-		let expiry = message.expiry();
+		let expiry = match message.expiry() {
+			Some(time) => time,
+			_ => return false,
+		};
 
 		self.cumulative_size += message.encoded_size();
 
@@ -232,8 +235,8 @@ impl Messages {
 
 		let sorted_entry = SortedEntry {
 			slab_id: id,
-			work_proved: work_proved,
-			expiry: expiry,
+			work_proved,
+			expiry,
 		};
 
 		match self.sorted.binary_search(&sorted_entry) {