request transaction proofs from on_demand

ethcore/src/client/client.rs

@@ -1616,7 +1616,6 @@ impl ::client::ProvingBlockChainClient for Client {
 		let options = TransactOptions { tracing: false, vm_tracing: false, check_nonce: false };
 		let res = Executive::new(&mut state, &env_info, &*self.engine, &self.factories.vm).transact(&transaction, options);
 
-
 		match res {
 			Err(ExecutionError::Internal(_)) => return None,
 			_ => return Some(state.drop().1.extract_proof()),

ethcore/src/env_info.rs

@@ -14,6 +14,8 @@
 // You should have received a copy of the GNU General Public License
 // along with Parity.  If not, see <http://www.gnu.org/licenses/>.
 
+//! Environment information for transaction execution.
+
 use std::cmp;
 use std::sync::Arc;
 use util::{U256, Address, H256, Hashable};
@@ -25,7 +27,7 @@ use ethjson;
 pub type LastHashes = Vec<H256>;
 
 /// Information concerning the execution environment for a message-call/contract-creation.
-#[derive(Debug)]
+#[derive(Debug, Clone)]
 pub struct EnvInfo {
 	/// The block number.
 	pub number: BlockNumber,

ethcore/src/lib.rs

@@ -79,7 +79,6 @@
 //!   cargo build --release
 //!   ```
 
-
 extern crate ethcore_io as io;
 extern crate rustc_serialize;
 extern crate crypto;
@@ -140,12 +139,12 @@ pub mod action_params;
 pub mod db;
 pub mod verification;
 pub mod state;
+pub mod env_info;
 #[macro_use] pub mod evm;
 
 mod cache_manager;
 mod blooms;
 mod basic_types;
-mod env_info;
 mod pod_account;
 mod state_db;
 mod account_db;

ethcore/src/state/mod.rs

@@ -31,6 +31,7 @@ use factory::Factories;
 use trace::FlatTrace;
 use pod_account::*;
 use pod_state::{self, PodState};
+use types::executed::{Executed, ExecutionError};
 use types::state_diff::StateDiff;
 use transaction::SignedTransaction;
 use state_db::StateDB;
@@ -60,6 +61,17 @@ pub struct ApplyOutcome {
 /// Result type for the execution ("application") of a transaction.
 pub type ApplyResult = Result<ApplyOutcome, Error>;
 
+/// Return type of proof validity check.
+#[derive(Debug, Clone)]
+pub enum ProvedExecution {
+	/// Proof wasn't enough to complete execution.
+	BadProof,
+	/// The transaction failed, but not due to a bad proof.
+	Failed(ExecutionError),
+	/// The transaction successfully completd with the given proof.
+	Complete(Executed),
+}
+
 #[derive(Eq, PartialEq, Clone, Copy, Debug)]
 /// Account modification state. Used to check if the account was
 /// Modified in between commits and overall.
@@ -150,6 +162,39 @@ impl AccountEntry {
 	}
 }
 
+/// Check the given proof of execution.
+/// `Err(ExecutionError::Internal)` indicates failure, everything else indicates
+/// a successful proof (as the transaction itself may be poorly chosen).
+pub fn check_proof(
+	proof: &[::util::DBValue],
+	root: H256,
+	transaction: &SignedTransaction,
+	engine: &Engine,
+	env_info: &EnvInfo,
+) -> ProvedExecution {
+	let backend = self::backend::ProofCheck::new(proof);
+	let mut factories = Factories::default();
+	factories.accountdb = ::account_db::Factory::Plain;
+
+	let res = State::from_existing(
+		backend,
+		root,
+		engine.account_start_nonce(),
+		factories
+	);
+
+	let mut state = match res {
+		Ok(state) => state,
+		Err(_) => return ProvedExecution::BadProof,
+	};
+
+	match state.execute(env_info, engine, transaction, false) {
+		Ok(executed) => ProvedExecution::Complete(executed),
+		Err(ExecutionError::Internal(_)) => ProvedExecution::BadProof,
+		Err(e) => ProvedExecution::Failed(e),
+	}
+}
+
 /// Representation of the entire state of all accounts in the system.
 ///
 /// `State` can work together with `StateDB` to share account cache.
@@ -548,16 +593,12 @@ impl<B: Backend> State<B> {
 		Ok(())
 	}
 
-	/// Execute a given transaction.
+	/// Execute a given transaction, producing a receipt and an optional trace.
 	/// This will change the state accordingly.
 	pub fn apply(&mut self, env_info: &EnvInfo, engine: &Engine, t: &SignedTransaction, tracing: bool) -> ApplyResult {
 //		let old = self.to_pod();
 
-		let options = TransactOptions { tracing: tracing, vm_tracing: false, check_nonce: true };
-		let vm_factory = self.factories.vm.clone();
-		let e = Executive::new(self, env_info, engine, &vm_factory).transact(t, options)?;
-
-		// TODO uncomment once to_pod() works correctly.
+		let e = self.execute(env_info, engine, t, tracing)?;
 //		trace!("Applied transaction. Diff:\n{}\n", state_diff::diff_pod(&old, &self.to_pod()));
 		let state_root = if env_info.number < engine.params().eip98_transition {
 			self.commit()?;
@@ -570,6 +611,15 @@ impl<B: Backend> State<B> {
 		Ok(ApplyOutcome{receipt: receipt, trace: e.trace})
 	}
 
+	// Execute a given transaction.
+	fn execute(&mut self, env_info: &EnvInfo, engine: &Engine, t: &SignedTransaction, tracing: bool) -> Result<Executed, ExecutionError> {
+		let options = TransactOptions { tracing: tracing, vm_tracing: false, check_nonce: true };
+		let vm_factory = self.factories.vm.clone();
+
+		Executive::new(self, env_info, engine, &vm_factory).transact(t, options)
+	}
+
+
 	/// Commit accounts to SecTrieDBMut. This is similar to cpp-ethereum's dev::eth::commit.
 	/// `accounts` is mutable because we may need to commit the code or storage and record that.
 	#[cfg_attr(feature="dev", allow(match_ref_pats))]