basic upgrade scenario

Cargo.lock

@@ -22,6 +22,7 @@ dependencies = [
  "rpassword 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-serialize 0.3.18 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc_version 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "semver 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "time 0.1.34 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 

Cargo.toml

@@ -29,7 +29,7 @@ ethminer = { path = "miner" }
 ethcore-devtools = { path = "devtools" }
 ethcore-rpc = { path = "rpc", optional = true }
 ethcore-webapp = { path = "webapp", optional = true }
-
+semver = "0.2"
 
 [dependencies.hyper]
 version = "0.8"

parity/main.rs

@@ -36,6 +36,7 @@ extern crate daemonize;
 extern crate time;
 extern crate number_prefix;
 extern crate rpassword;
+extern crate semver;
 
 // for price_info.rs
 #[macro_use] extern crate hyper;
@@ -71,6 +72,7 @@ use rpc::Server as RpcServer;
 use webapp::Listening as WebappServer;
 
 mod price_info;
+mod upgrade;
 
 fn die_with_message(msg: &str) -> ! {
 	println!("ERROR: {}", msg);

parity/upgrade.rs

@@ -0,0 +1,84 @@
+// Copyright 2015, 2016 Ethcore (UK) Ltd.
+// This file is part of Parity.
+
+// Parity is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Parity is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Parity.  If not, see <http://www.gnu.org/licenses/>.
+
+//! Parity upgrade logic
+
+use semver::Version;
+use std::collections::*;
+use std::path::*;
+
+struct Error;
+
+const CURRENT_VERSION: &'static str = env!("CARGO_PKG_VERSION");
+
+#[derive(Hash, PartialEq, Eq)]
+struct UpgradeKey {
+	pub old_version: Version,
+	pub new_version: Version,
+}
+
+type UpgradeList = HashMap<UpgradeKey, fn() -> Result<(), Error>>;
+
+impl UpgradeKey {
+	// given the following config exist
+	// ver.lock 1.1 (`previous_version`)
+	//
+	//  current_version 1.4 (`current_version`)
+	//
+	//
+	//upgrades (set of `UpgradeKey`)
+	//	1.0 -> 1.1 (u1)
+	//	1.1 -> 1.2 (u2)
+	//	1.2 -> 1.3 (u3)
+	//	1.3 -> 1.4 (u4)
+	//	1.4 -> 1.5 (u5)
+	//
+	// then the following upgrades should be applied:
+	// u2, u3, u4
+	fn is_applicable(&self, previous_version: &Version, current_version: &Version) -> bool {
+		self.old_version >= *previous_version && self.new_version <= *current_version
+	}
+}
+
+// dummy upgrade (remove when the first one is in)
+fn dummy_upgrade() -> Result<(), Error> {
+	Ok(())
+}
+
+fn push_updrades(upgrades: &mut UpgradeList)
+{
+	// dummy upgrade (remove when the first one is in)
+	upgrades.insert(
+		UpgradeKey { old_version: Version::parse("1.0.0").unwrap(), new_version: Version::parse("99.99.0").unwrap() },
+		dummy_upgrade);
+}
+
+fn upgrade_from_version(previous_version: &Version) -> Result<usize, Error> {
+	let mut upgrades = HashMap::new();
+	push_updrades(&mut upgrades);
+
+	let current_version = Version::parse(CURRENT_VERSION).unwrap();
+
+	let mut count = 0;
+	for upgrade_key in upgrades.keys() {
+		if upgrade_key.is_applicable(previous_version, &current_version) {
+			let upgrade_script = upgrades[upgrade_key];
+			try!(upgrade_script());
+			count = count + 1;
+		}
+	}
+	Ok(count)
+}