hal_simplicity/actions/simplicity/pset/
finalize.rs

1// Copyright 2025 Andrew Poelstra
2// SPDX-License-Identifier: CC0-1.0
3
4use crate::hal_simplicity::Program;
5use crate::simplicity::jet;
6
7use super::{execution_environment, PsetError, UpdatedPset};
8
9#[derive(Debug, thiserror::Error)]
10pub enum PsetFinalizeError {
11	#[error(transparent)]
12	SharedError(#[from] PsetError),
13
14	#[error("invalid PSET: {0}")]
15	PsetDecode(elements::pset::ParseError),
16
17	#[error("invalid input index: {0}")]
18	InputIndexParse(std::num::ParseIntError),
19
20	#[error("invalid program: {0}")]
21	ProgramParse(simplicity::ParseError),
22
23	#[error("program does not have a redeem node")]
24	NoRedeemNode,
25
26	#[error("failed to prune program: {0}")]
27	ProgramPrune(simplicity::bit_machine::ExecutionError),
28}
29
30/// Attach a Simplicity program and witness to a PSET input
31pub fn pset_finalize(
32	pset_b64: &str,
33	input_idx: &str,
34	program: &str,
35	witness: &str,
36	genesis_hash: Option<&str>,
37) -> Result<UpdatedPset, PsetFinalizeError> {
38	// 1. Parse everything.
39	let mut pset: elements::pset::PartiallySignedTransaction =
40		pset_b64.parse().map_err(PsetFinalizeError::PsetDecode)?;
41	let input_idx: u32 = input_idx.parse().map_err(PsetFinalizeError::InputIndexParse)?;
42	let input_idx_usize = input_idx as usize; // 32->usize cast ok on almost all systems
43
44	let program = Program::<jet::Elements>::from_str(program, Some(witness))
45		.map_err(PsetFinalizeError::ProgramParse)?;
46
47	// 2. Extract transaction environment.
48	let (tx_env, control_block, tap_leaf) =
49		execution_environment(&pset, input_idx_usize, program.cmr(), genesis_hash)?;
50	let cb_serialized = control_block.serialize();
51
52	// 3. Prune program.
53	let redeem_node = program.redeem_node().ok_or(PsetFinalizeError::NoRedeemNode)?;
54	let pruned = redeem_node.prune(&tx_env).map_err(PsetFinalizeError::ProgramPrune)?;
55
56	let (prog, witness) = pruned.to_vec_with_witness();
57	// If `execution_environment` above succeeded we are guaranteed that this index is in bounds.
58	let input = &mut pset.inputs_mut()[input_idx_usize];
59	input.final_script_witness = Some(vec![witness, prog, tap_leaf.into_bytes(), cb_serialized]);
60
61	let updated_values = vec!["final_script_witness"];
62
63	Ok(UpdatedPset {
64		pset: pset.to_string(),
65		updated_values,
66	})
67}
hal_simplicity/actions/simplicity/pset/finalize.rs

hal_simplicity/actions/simplicity/pset/
finalize.rs
