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// Copyright (C) 2019-2022 Aleo Systems Inc.
// This file is part of the snarkVM library.
// The snarkVM library 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.
// The snarkVM library 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 the snarkVM library. If not, see <https://www.gnu.org/licenses/>.
use super::*;
impl<N: Network> Process<N> {
/// Executes the given authorization.
#[inline]
pub fn execute<A: circuit::Aleo<Network = N>, R: Rng + CryptoRng>(
&self,
authorization: Authorization<N>,
rng: &mut R,
) -> Result<(Response<N>, Execution<N>)> {
// Retrieve the main request (without popping it).
let request = authorization.peek_next()?;
#[cfg(feature = "aleo-cli")]
println!("{}", format!(" • Executing '{}/{}'...", request.program_id(), request.function_name()).dimmed());
// Initialize the execution.
let execution = Arc::new(RwLock::new(Execution::new()));
// Retrieve the stack.
let stack = self.get_stack(request.program_id())?;
// Execute the circuit.
let response = stack.execute_function::<A, R>(CallStack::execute(authorization, execution.clone())?, rng)?;
// Extract the execution.
let execution = execution.read().clone();
// Ensure the execution is not empty.
ensure!(!execution.is_empty(), "Execution of '{}/{}' is empty", request.program_id(), request.function_name());
Ok((response, execution))
}
/// Verifies the given execution is valid.
#[inline]
pub fn verify_execution(&self, execution: &Execution<N>) -> Result<()> {
// Retrieve the edition.
let edition = execution.edition();
// Ensure the edition matches.
ensure!(edition == N::EDITION, "Executed the wrong edition (expected '{}', found '{edition}').", N::EDITION);
// Ensure the execution contains transitions.
ensure!(!execution.is_empty(), "There are no transitions in the execution");
// Ensure the number of transitions matches the program function.
{
// Retrieve the transition (without popping it).
let transition = execution.peek()?;
// Retrieve the stack.
let stack = self.get_stack(transition.program_id())?;
// Ensure the number of calls matches the number of transitions.
let number_of_calls = stack.get_number_of_calls(transition.function_name())?;
ensure!(
number_of_calls == execution.len(),
"The number of transitions in the execution is incorrect. Expected {number_of_calls}, but found {}",
execution.len()
);
}
// Replicate the execution stack for verification.
let mut queue = execution.clone();
// Verify each transition.
while let Ok(transition) = queue.pop() {
#[cfg(debug_assertions)]
println!("Verifying transition for {}/{}...", transition.program_id(), transition.function_name());
// Ensure the transition ID is correct.
ensure!(**transition.id() == transition.to_root()?, "The transition ID is incorrect");
// Ensure the number of inputs is within the allowed range.
ensure!(transition.inputs().len() <= N::MAX_INPUTS, "Transition exceeded maximum number of inputs");
// Ensure the number of outputs is within the allowed range.
ensure!(transition.outputs().len() <= N::MAX_INPUTS, "Transition exceeded maximum number of outputs");
// Ensure each input is valid.
if transition.inputs().iter().enumerate().any(|(index, input)| !input.verify(transition.tcm(), index)) {
bail!("Failed to verify a transition input")
}
// Ensure each output is valid.
let num_inputs = transition.inputs().len();
if transition
.outputs()
.iter()
.enumerate()
.any(|(index, output)| !output.verify(transition.tcm(), num_inputs + index))
{
bail!("Failed to verify a transition output")
}
// Ensure the fee is correct.
match Program::is_coinbase(transition.program_id(), transition.function_name()) {
true => ensure!(transition.fee() < &0, "The fee must be negative in a coinbase transition"),
false => ensure!(transition.fee() >= &0, "The fee must be zero or positive"),
}
// Compute the x- and y-coordinate of `tpk`.
let (tpk_x, tpk_y) = transition.tpk().to_xy_coordinate();
// [Inputs] Construct the verifier inputs to verify the proof.
let mut inputs = vec![N::Field::one(), *tpk_x, *tpk_y, **transition.tcm()];
// [Inputs] Extend the verifier inputs with the input IDs.
inputs.extend(transition.inputs().iter().flat_map(|input| input.verifier_inputs()));
// Retrieve the stack.
let stack = self.get_stack(transition.program_id())?;
// Retrieve the function from the stack.
let function = stack.get_function(transition.function_name())?;
// Determine the number of function calls in this function.
let mut num_function_calls = 0;
for instruction in function.instructions() {
if let Instruction::Call(call) = instruction {
// Determine if this is a function call.
if call.is_function_call(stack)? {
num_function_calls += 1;
}
}
}
// If there are function calls, append their inputs and outputs.
if num_function_calls > 0 {
// This loop takes the last `num_function_call` transitions, and reverses them
// to order them in the order they were defined in the function.
for transition in (*queue).iter().rev().take(num_function_calls).rev() {
// [Inputs] Extend the verifier inputs with the input IDs of the external call.
inputs.extend(transition.inputs().iter().flat_map(|input| input.verifier_inputs()));
// [Inputs] Extend the verifier inputs with the output IDs of the external call.
inputs.extend(transition.output_ids().map(|id| **id));
}
}
// [Inputs] Extend the verifier inputs with the output IDs.
inputs.extend(transition.outputs().iter().flat_map(|output| output.verifier_inputs()));
// Ensure the transition contains finalize inputs, if the function has a finalize scope.
if let Some((command, logic)) = function.finalize() {
// Ensure the transition contains finalize inputs.
match transition.finalize() {
Some(finalize) => {
// Retrieve the number of operands.
let num_operands = command.operands().len();
// Retrieve the number of inputs.
let num_inputs = logic.inputs().len();
// Ensure the number of inputs for finalize is within the allowed range.
ensure!(finalize.len() <= N::MAX_INPUTS, "Transition exceeds maximum inputs for finalize");
// Ensure the number of inputs for finalize matches in the finalize command.
ensure!(finalize.len() == num_operands, "The number of inputs for finalize is incorrect");
// Ensure the number of inputs for finalize matches in the finalize logic.
ensure!(finalize.len() == num_inputs, "The number of inputs for finalize is incorrect");
// Convert the finalize inputs into concatenated bits.
let finalize_bits = finalize.iter().flat_map(ToBits::to_bits_le).collect::<Vec<_>>();
// Compute the checksum of the finalize inputs.
let checksum = N::hash_bhp1024(&finalize_bits)?;
// [Inputs] Extend the verifier inputs with the inputs for finalize.
inputs.push(*checksum);
}
None => bail!("The transition is missing inputs for 'finalize'"),
}
}
// [Inputs] Extend the verifier inputs with the fee.
inputs.push(*I64::<N>::new(*transition.fee()).to_field()?);
#[cfg(debug_assertions)]
println!("Transition public inputs ({} elements): {:#?}", inputs.len(), inputs);
// Retrieve the verifying key.
let verifying_key = self.get_verifying_key(transition.program_id(), transition.function_name())?;
// Ensure the proof is valid.
ensure!(
verifying_key.verify(transition.function_name(), &inputs, transition.proof()),
"Transition is invalid"
);
}
Ok(())
}
/// Finalizes the execution.
/// This method assumes the given execution **is valid**.
#[inline]
pub fn finalize_execution<P: ProgramStorage<N>>(
&self,
store: &ProgramStore<N, P>,
execution: &Execution<N>,
) -> Result<()> {
// Ensure the execution contains transitions.
ensure!(!execution.is_empty(), "There are no transitions in the execution");
// Ensure the number of transitions matches the program function.
{
// Retrieve the transition (without popping it).
let transition = execution.peek()?;
// Retrieve the stack.
let stack = self.get_stack(transition.program_id())?;
// Ensure the number of calls matches the number of transitions.
let number_of_calls = stack.get_number_of_calls(transition.function_name())?;
ensure!(
number_of_calls == execution.len(),
"The number of transitions in the execution is incorrect. Expected {number_of_calls}, but found {}",
execution.len()
);
}
// TODO (howardwu): This is a temporary approach. We should create a "CallStack" and recurse through the stack.
// Currently this loop assumes a linearly execution stack.
// Finalize each transition, starting from the last one.
#[allow(clippy::into_iter_on_ref)]
for transition in execution.into_iter().rev() {
#[cfg(debug_assertions)]
println!("Finalizing transition for {}/{}...", transition.program_id(), transition.function_name());
// Retrieve the stack.
let stack = self.get_stack(transition.program_id())?;
// Retrieve the function name.
let function_name = transition.function_name();
// If there is a finalize scope, finalize the function.
if let Some((_, finalize)) = stack.get_function(function_name)?.finalize() {
// Retrieve the finalize inputs.
let inputs = match transition.finalize() {
Some(inputs) => inputs,
// Ensure the transition contains finalize inputs.
None => bail!("The transition is missing inputs for 'finalize'"),
};
// Initialize the registers.
let mut registers = FinalizeRegisters::<N>::new(stack.get_finalize_types(finalize.name())?.clone());
// Store the inputs.
finalize.inputs().iter().map(|i| i.register()).zip_eq(inputs).try_for_each(|(register, input)| {
// Assign the input value to the register.
registers.store(stack, register, input.clone())
})?;
// Evaluate the commands.
for command in finalize.commands() {
// If the evaluation fails, bail and return the error.
if let Err(error) = command.evaluate_finalize(stack, store, &mut registers) {
bail!("'finalize' failed to evaluate command ({command}): {error}");
}
}
// Retrieve the output registers.
let output_registers =
&finalize.outputs().iter().map(|output| output.register().clone()).collect::<Vec<_>>();
// TODO (howardwu): Save the outputs in ProgramStore.
// Load the outputs.
let _outputs = output_registers
.iter()
.map(|register| {
// Retrieve the stack value from the register.
registers.load(stack, &Operand::Register(register.clone()))
})
.collect::<Result<Vec<_>>>()?;
}
}
Ok(())
}
}