Make builtins work.

Cargo.toml

@@ -9,7 +9,7 @@ authors = ["Ethcore <admin@ethcore.io>"]
 [dependencies]
 log = "0.3"
 env_logger = "0.3"
-ethcore-util = "0.1.0"
+ethcore-util = { path = "../ethcore-util" }
 rustc-serialize = "0.3"
 flate2 = "0.2"
 rocksdb = "0.2.1"

src/builtin.rs

@@ -1,4 +1,6 @@
+use std::cmp::min;
 use util::uint::*;
+use rustc_serialize::json::Json;
 
 /// Definition of a contract whose implementation is built-in. 
 pub struct Builtin {
@@ -8,3 +10,112 @@ pub struct Builtin {
 	/// being placed into the second.
 	pub execute: Box<Fn(&[u8], &mut [u8])>,
 }
+
+/*
+ETH_REGISTER_PRECOMPILED(ecrecover)(bytesConstRef _in, bytesRef _out)
+{
+	struct inType
+	{
+		h256 hash;
+		h256 v;
+		h256 r;
+		h256 s;
+	} in;
+
+	memcpy(&in, _in.data(), min(_in.size(), sizeof(in)));
+
+	h256 ret;
+	u256 v = (u256)in.v;
+	if (v >= 27 && v <= 28)
+	{
+		SignatureStruct sig(in.r, in.s, (byte)((int)v - 27));
+		if (sig.isValid())
+		{
+			try
+			{
+				if (Public rec = recover(sig, in.hash))
+				{
+					ret = dev::sha3(rec);
+					memset(ret.data(), 0, 12);
+					ret.ref().copyTo(_out);
+				}
+			}
+			catch (...) {}
+		}
+	}
+}
+
+ETH_REGISTER_PRECOMPILED(sha256)(bytesConstRef _in, bytesRef _out)
+{
+	dev::sha256(_in).ref().copyTo(_out);
+}
+
+ETH_REGISTER_PRECOMPILED(ripemd160)(bytesConstRef _in, bytesRef _out)
+{
+	h256(dev::ripemd160(_in), h256::AlignRight).ref().copyTo(_out);
+}
+*/
+
+impl Builtin {
+	/// Create a new object from components.
+	pub fn new(cost: Box<Fn(usize) -> U256>, execute: Box<Fn(&[u8], &mut [u8])>) -> Builtin {
+		Builtin {cost: cost, execute: execute}
+	}
+
+	/// Create a new object from a builtin-function name with a linear cost associated with input size.
+	pub fn from_named_linear(name: &str, base_cost: usize, word_cost: usize) -> Option<Builtin> {
+		new_builtin_exec(name).map(|b| {
+			let cost = Box::new(move|s: usize| -> U256 {U256::from(base_cost) + U256::from(word_cost) * U256::from((s + 31) / 32)});
+			Self::new(cost, b)
+		})
+	}
+
+	/// Create a builtin from JSON.
+	///
+	/// JSON must be of the form `{ "name": "identity", "linear": {"base": 10, "word": 20} }`.
+	pub fn from_json(json: &Json) -> Option<Builtin> {
+		// NICE: figure out a more convenient means of handing errors here.
+		if let Json::String(ref name) = json["name"] {
+			if let Json::Object(ref o) = json["linear"] {
+				if let Json::U64(ref word) = o["word"] {
+					if let Json::U64(ref base) = o["base"] {
+						return Self::from_named_linear(&name[..], *base as usize, *word as usize);
+					}
+				}
+			}
+		}
+		None
+	}
+}
+
+// TODO: turn in to a factory with dynamic registration.
+pub fn new_builtin_exec(name: &str) -> Option<Box<Fn(&[u8], &mut [u8])>> {
+	match name {
+		"identity" => Some(Box::new(move|input: &[u8], output: &mut[u8]| {
+			for i in 0..min(input.len(), output.len()) {
+				output[i] = input[i];
+			}
+		})),
+		"ecrecover" => Some(Box::new(move|_input: &[u8], _output: &mut[u8]| {
+			unimplemented!();
+		})),
+		"sha256" => Some(Box::new(move|_input: &[u8], _output: &mut[u8]| {
+			unimplemented!();
+		})),
+		"ripemd160" => Some(Box::new(move|_input: &[u8], _output: &mut[u8]| {
+			unimplemented!();
+		})),
+		_ => None
+	}
+}
+
+#[test]
+fn identity() {
+	let f = new_builtin_exec("identity").unwrap();
+	let i = [0u8, 1, 2, 3];
+	for osize in [2, 4, 8].iter() {
+		let mut o = vec![255u8; *osize];
+		f(&i[..], &mut o[..]);
+		assert_eq!(i[..], o[..]);
+	}
+}

src/spec.rs

@@ -20,6 +20,8 @@ use null_engine::NullEngine;
 use denominations::*;
 use header::*;
 
+// TODO: need a JSON->cost closure converter.
+
 /// Converts file from base64 gzipped bytes to json
 pub fn base_to_json(source: &[u8]) -> Json {
 	// there is probably no need to store genesis in based64 gzip,
@@ -139,25 +141,28 @@ impl Spec {
 	}
 }
 
-
 impl Spec {
 	/// Loads a chain-specification from a json data structure
 	pub fn from_json(json: Json) -> Spec {
 		// once we commit ourselves to some json parsing library (serde?)
 		// move it to proper data structure
 		let mut state = HashMap::new();
+		let mut builtins = HashMap::new();
+
 		let accounts = json["alloc"].as_object().expect("Missing genesis state");
 		for (address, acc) in accounts.iter() {
 			let addr = Address::from_str(address).unwrap();
 			let o = acc.as_object().unwrap();
-			let balance = U256::from_dec_str(o["balance"].as_string().unwrap()).unwrap();
-			state.insert(addr, Account::new_basic(balance, U256::from(0)));
+			if let Json::Object(_) = o["precompiled"] {
+				if let Some(b) = Builtin::from_json(&o["precompiled"]) {
+					builtins.insert(addr.clone(), b);
+				}
+			}
+			let balance = U256::from_dec_str(o["balance"].as_string().unwrap_or("0")).unwrap();
+			let nonce = U256::from_dec_str(o["nonce"].as_string().unwrap_or("0")).unwrap();
+			// TODO: handle code & data is they exist.
+			state.insert(addr, Account::new_basic(balance, nonce));
 		}
-
-		let builtins = {
-			// TODO: populate from json.
-			HashMap::new()
-		};
 
 		let (seal_fields, seal_rlp) = {
 			if json.find("mixhash").is_some() && json.find("nonce").is_some() {
@@ -189,6 +194,15 @@ impl Spec {
 		}
 	}
 
+	fn standard_builtins() -> HashMap<Address, Builtin> {
+		let mut ret = HashMap::new();
+		ret.insert(Address::from_str("0000000000000000000000000000000000000001").unwrap(), Builtin::from_named_linear("ecrecover", 3000, 0).unwrap());
+		ret.insert(Address::from_str("0000000000000000000000000000000000000002").unwrap(), Builtin::from_named_linear("sha256", 60, 12).unwrap());
+		ret.insert(Address::from_str("0000000000000000000000000000000000000003").unwrap(), Builtin::from_named_linear("ripemd160", 600, 120).unwrap());
+		ret.insert(Address::from_str("0000000000000000000000000000000000000004").unwrap(), Builtin::from_named_linear("identity", 15, 3).unwrap());
+		ret
+	}
+
 	/// Creates the Olympic network chain spec.
 	pub fn olympic() -> Spec {
 		Spec {
@@ -207,7 +221,7 @@ impl Spec {
 				acc.insert(vec.0.to_string(), vec.1);
 				acc
 			}),
-			builtins: HashMap::new(),			// TODO: make correct
+			builtins: Self::standard_builtins(),
 			parent_hash: H256::new(),
 			author: Address::new(),
 			difficulty: U256::from(131_072u64),
@@ -245,7 +259,7 @@ impl Spec {
 				acc.insert(vec.0.to_string(), vec.1);
 				acc
 			}),
-			builtins: HashMap::new(),			// TODO: make correct
+			builtins: Self::standard_builtins(),
 			parent_hash: H256::new(),
 			author: Address::new(),
 			difficulty: U256::from(131_072u64),
@@ -283,7 +297,7 @@ impl Spec {
 				acc.insert(vec.0.to_string(), vec.1);
 				acc
 			}),
-			builtins: HashMap::new(),			// TODO: make correct
+			builtins: Self::standard_builtins(),
 			parent_hash: H256::new(),
 			author: Address::new(),
 			difficulty: U256::from(131_072u64),