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// Copyright (c) 2019-2025 Provable Inc.
// This file is part of the snarkVM library.
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at:
// http://www.apache.org/licenses/LICENSE-2.0
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
use super::*;
impl<N: Network> Stack<N> {
/// Evaluates a program closure on the given inputs.
///
/// # Errors
/// This method will halt if the given inputs are not the same length as the input statements.
pub fn evaluate_closure<A: circuit::Aleo<Network = N>>(
&self,
closure: &Closure<N>,
inputs: &[Value<N>],
call_stack: CallStack<N>,
signer: Address<N>,
caller: Address<N>,
tvk: Field<N>,
) -> Result<Vec<Value<N>>> {
let timer = timer!("Stack::evaluate_closure");
// Ensure the number of inputs matches the number of input statements.
if closure.inputs().len() != inputs.len() {
bail!("Expected {} inputs, found {}", closure.inputs().len(), inputs.len())
}
// Initialize the registers.
let mut registers =
Registers::<N, A>::new(call_stack.clone(), self.get_register_types(closure.name())?.clone());
// Set the transition signer.
registers.set_signer(signer);
// Set the transition caller.
registers.set_caller(caller);
// Set the transition view key.
registers.set_tvk(tvk);
lap!(timer, "Initialize the registers");
// Store the inputs.
closure.inputs().iter().map(|i| i.register()).zip_eq(inputs).try_for_each(|(register, input)| {
// Assign the input value to the register.
registers.store(self, register, input.clone())
})?;
lap!(timer, "Store the inputs");
// Evaluate the instructions.
for instruction in closure.instructions() {
// If the evaluation fails, bail and return the error.
if let Err(error) = instruction.evaluate(self, &mut registers) {
bail!("Failed to evaluate instruction ({instruction}): {error}");
}
}
lap!(timer, "Evaluate the instructions");
// Load the outputs.
let outputs = closure
.outputs()
.iter()
.map(|output| {
match output.operand() {
// If the operand is a literal, use the literal directly.
Operand::Literal(literal) => Ok(Value::Plaintext(Plaintext::from(literal))),
// If the operand is a register, retrieve the stack value from the register.
Operand::Register(register) => registers.load(self, &Operand::Register(register.clone())),
// If the operand is the program ID, convert the program ID into an address.
Operand::ProgramID(program_id) => {
Ok(Value::Plaintext(Plaintext::from(Literal::Address(program_id.to_address()?))))
}
// If the operand is the signer, retrieve the signer from the registers.
Operand::Signer => Ok(Value::Plaintext(Plaintext::from(Literal::Address(registers.signer()?)))),
// If the operand is the caller, retrieve the caller from the registers.
Operand::Caller => Ok(Value::Plaintext(Plaintext::from(Literal::Address(registers.caller()?)))),
// If the operand is the block height, throw an error.
Operand::BlockHeight => bail!("Cannot retrieve the block height from a closure scope."),
// If the operand is the network id, throw an error.
Operand::NetworkID => bail!("Cannot retrieve the network ID from a closure scope."),
// If the operand is the program checksum, throw an error.
Operand::Checksum(_) => bail!("Cannot retrieve the program checksum from a closure scope."),
// If the operand is the program edition, throw an error.
Operand::Edition(_) => bail!("Cannot retrieve the edition from a closure scope."),
// If the operand is the program owner, throw an error.
Operand::ProgramOwner(_) => bail!("Cannot retrieve the program owner from a closure scope."),
}
})
.collect();
lap!(timer, "Load the outputs");
finish!(timer);
outputs
}
/// Evaluates a program function on the given inputs.
///
/// # Errors
/// This method will halt if the given inputs are not the same length as the input statements.
pub fn evaluate_function<A: circuit::Aleo<Network = N>, R: CryptoRng + Rng>(
&self,
mut call_stack: CallStack<N>,
caller: Option<ProgramID<N>>,
root_tvk: Option<Field<N>>,
rng: &mut R,
) -> Result<Response<N>> {
let timer = timer!("Stack::evaluate_function");
// Retrieve the next request, based on the call stack mode.
let (request, call_stack) = match &mut call_stack {
CallStack::Authorize(..) => (call_stack.pop()?, call_stack),
CallStack::Evaluate(authorization) => (authorization.next()?, call_stack),
// If the evaluation is performed in the `Execute` mode, create a new `Evaluate` mode.
// This is done to ensure that evaluation during execution is performed consistently.
CallStack::Execute(authorization, _) => {
// Note: We need to replicate the authorization, so that 'execute' can call 'authorization.next()?'.
// This way, the authorization remains unmodified in this 'evaluate' scope.
let authorization = authorization.replicate();
let request = authorization.next()?;
let call_stack = CallStack::Evaluate(authorization);
(request, call_stack)
}
_ => bail!(
"Illegal operation: call stack must be `Authorize`, `Evaluate` or `Execute` in `evaluate_function`."
),
};
lap!(timer, "Retrieve the next request");
// Ensure the network ID matches.
ensure!(
**request.network_id() == N::ID,
"Network ID mismatch. Expected {}, but found {}",
N::ID,
request.network_id()
);
// Retrieve the function, inputs, and transition view key.
let function = self.get_function(request.function_name())?;
let inputs = request.inputs();
let signer = *request.signer();
let (is_root, caller) = match caller {
// If a caller is provided, then this is an evaluation of a child function.
Some(caller) => (false, caller.to_address()?),
// If no caller is provided, then this is an evaluation of a top-level function.
None => (true, signer),
};
let tvk = *request.tvk();
// Retrieve the program checksum, if the program has a constructor.
let program_checksum = match self.program().contains_constructor() {
true => Some(self.program_checksum_as_field()?),
false => None,
};
// Ensure the number of inputs matches.
if function.inputs().len() != inputs.len() {
bail!(
"Function '{}' in the program '{}' expects {} inputs, but {} were provided.",
function.name(),
self.program.id(),
function.inputs().len(),
inputs.len()
)
}
lap!(timer, "Perform input checks");
// Initialize the registers.
let mut registers = Registers::<N, A>::new(call_stack, self.get_register_types(function.name())?.clone());
// Set the transition signer.
registers.set_signer(signer);
// Set the transition caller.
registers.set_caller(caller);
// Set the transition view key.
registers.set_tvk(tvk);
// Set the root tvk.
if let Some(root_tvk) = root_tvk {
registers.set_root_tvk(root_tvk);
} else {
registers.set_root_tvk(tvk);
}
lap!(timer, "Initialize the registers");
// Ensure the request is well-formed.
ensure!(request.verify(&function.input_types(), is_root, program_checksum), "[Evaluate] Request is invalid");
lap!(timer, "Verify the request");
// Store the inputs.
function.inputs().iter().map(|i| i.register()).zip_eq(inputs).try_for_each(|(register, input)| {
// Assign the input value to the register.
registers.store(self, register, input.clone())
})?;
lap!(timer, "Store the inputs");
// Evaluate the instructions.
// Note: We handle the `call` instruction separately, as it requires special handling.
for instruction in function.instructions() {
// Evaluate the instruction.
let result = match instruction {
// If the instruction is a `call` instruction, we need to handle it separately.
Instruction::Call(call) => CallTrait::evaluate(call, self, &mut registers, rng),
// Otherwise, evaluate the instruction normally.
_ => instruction.evaluate(self, &mut registers),
};
// If the evaluation fails, bail and return the error.
if let Err(error) = result {
bail!("Failed to evaluate instruction ({instruction}): {error}");
}
}
lap!(timer, "Evaluate the instructions");
// Retrieve the output operands.
let output_operands = &function.outputs().iter().map(|output| output.operand()).collect::<Vec<_>>();
lap!(timer, "Retrieve the output operands");
// Load the outputs.
let outputs = output_operands
.iter()
.map(|operand| {
match operand {
// If the operand is a literal, use the literal directly.
Operand::Literal(literal) => Ok(Value::Plaintext(Plaintext::from(literal))),
// If the operand is a register, retrieve the stack value from the register.
Operand::Register(register) => registers.load(self, &Operand::Register(register.clone())),
// If the operand is the program ID, convert the program ID into an address.
Operand::ProgramID(program_id) => {
Ok(Value::Plaintext(Plaintext::from(Literal::Address(program_id.to_address()?))))
}
// If the operand is the signer, retrieve the signer from the registers.
Operand::Signer => Ok(Value::Plaintext(Plaintext::from(Literal::Address(registers.signer()?)))),
// If the operand is the caller, retrieve the caller from the registers.
Operand::Caller => Ok(Value::Plaintext(Plaintext::from(Literal::Address(registers.caller()?)))),
// If the operand is the block height, throw an error.
Operand::BlockHeight => bail!("Cannot retrieve the block height from a function scope."),
// If the operand is the network id, throw an error.
Operand::NetworkID => bail!("Cannot retrieve the network ID from a function scope."),
// If the operand is the program checksum, throw an error.
Operand::Checksum(_) => bail!("Cannot retrieve the program checksum from a function scope."),
// If the operand is the program edition, throw an error.
Operand::Edition(_) => bail!("Cannot retrieve the edition from a function scope."),
// If the operand is the program owner, throw an error.
Operand::ProgramOwner(_) => bail!("Cannot retrieve the program owner from a function scope."),
}
})
.collect::<Result<Vec<_>>>()?;
lap!(timer, "Load the outputs");
// Map the output operands to registers.
let output_registers = output_operands
.iter()
.map(|operand| match operand {
Operand::Register(register) => Some(register.clone()),
_ => None,
})
.collect::<Vec<_>>();
lap!(timer, "Loaded the output registers");
// Compute the response.
let response = Response::new(
request.signer(),
request.network_id(),
self.program.id(),
function.name(),
request.inputs().len(),
request.tvk(),
request.tcm(),
outputs,
&function.output_types(),
&output_registers,
)?;
finish!(timer);
// If the circuit is in `Authorize` mode, then save the transition.
if let CallStack::Authorize(_, _, authorization) = registers.call_stack_ref() {
// Construct the transition.
let transition = Transition::from(&request, &response, &function.output_types(), &output_registers)?;
// Add the transition to the authorization.
authorization.insert_transition(transition)?;
lap!(timer, "Save the transition");
}
Ok(response)
}
}