chore: move nargo I/O into separate module (#896)

* chore: move IO logic into separate module

* chore: remove preprocessing from io module

* chore: replace if-lets with match

crates/nargo/src/cli/check_cmd.rs

@@ -8,7 +8,8 @@ use std::{
     path::{Path, PathBuf},
 };
 
-use super::{add_std_lib, write_to_file, NargoConfig};
+use super::fs::write_to_file;
+use super::{add_std_lib, NargoConfig};
 use crate::constants::{PROVER_INPUT_FILE, VERIFIER_INPUT_FILE};
 
 /// Checks the constraint system for errors

crates/nargo/src/cli/compile_cmd.rs

@@ -1,16 +1,13 @@
+use acvm::acir::circuit::Circuit;
 use acvm::ProofSystemCompiler;
-use acvm::{acir::circuit::Circuit, hash_constraint_system};
 use std::path::{Path, PathBuf};
 
 use clap::Args;
 
-use crate::{
-    constants::{ACIR_EXT, PK_EXT, TARGET_DIR, VK_EXT},
-    errors::CliError,
-    resolver::Resolver,
-};
+use crate::{constants::TARGET_DIR, errors::CliError, resolver::Resolver};
 
-use super::{add_std_lib, create_named_dir, write_to_file, NargoConfig};
+use super::fs::{acir::save_acir_to_dir, keys::save_key_to_dir};
+use super::{add_std_lib, NargoConfig};
 
 /// Compile the program and its secret execution trace into ACIR format
 #[derive(Debug, Clone, Args)]
@@ -81,41 +78,3 @@ fn preprocess_with_path<P: AsRef<Path>>(
 
     Ok((pk_path, vk_path))
 }
-
-fn save_acir_to_dir<P: AsRef<Path>>(
-    circuit: &Circuit,
-    circuit_name: &str,
-    circuit_dir: P,
-) -> PathBuf {
-    let mut circuit_path = create_named_dir(circuit_dir.as_ref(), "target");
-    circuit_path.push(circuit_name);
-
-    let mut serialized = Vec::new();
-    circuit.write(&mut serialized).expect("could not serialize circuit");
-
-    circuit_path.set_extension(ACIR_EXT);
-    write_to_file(serialized.as_slice(), &circuit_path);
-
-    // Save a checksum of the circuit to compare against during proving and verification
-    let acir_hash = hash_constraint_system(circuit);
-    circuit_path.set_extension(ACIR_EXT.to_owned() + ".sha256");
-    write_to_file(hex::encode(acir_hash).as_bytes(), &circuit_path);
-
-    circuit_path
-}
-
-fn save_key_to_dir<P: AsRef<Path>>(
-    key: Vec<u8>,
-    key_name: &str,
-    key_dir: P,
-    is_proving_key: bool,
-) -> Result<PathBuf, CliError> {
-    let mut key_path = create_named_dir(key_dir.as_ref(), key_name);
-    key_path.push(key_name);
-    let extension = if is_proving_key { PK_EXT } else { VK_EXT };
-    key_path.set_extension(extension);
-
-    write_to_file(hex::encode(key).as_bytes(), &key_path);
-
-    Ok(key_path)
-}

crates/nargo/src/cli/contract_cmd.rs

@@ -1,4 +1,5 @@
-use super::{create_named_dir, write_to_file, NargoConfig};
+use super::fs::{create_named_dir, write_to_file};
+use super::NargoConfig;
 use crate::{cli::compile_cmd::compile_circuit, constants::CONTRACT_DIR, errors::CliError};
 use acvm::SmartContract;
 use clap::Args;

crates/nargo/src/cli/execute_cmd.rs

@@ -1,17 +1,16 @@
-use std::path::{Path, PathBuf};
+use std::path::Path;
 
-use acvm::acir::native_types::Witness;
 use acvm::PartialWitnessGenerator;
 use clap::Args;
 use noirc_abi::input_parser::{Format, InputValue};
 use noirc_abi::{InputMap, WitnessMap};
 use noirc_driver::CompiledProgram;
 
+use super::fs::{inputs::read_inputs_from_file, witness::save_witness_to_dir};
 use super::NargoConfig;
-use super::{create_named_dir, read_inputs_from_file, write_to_file};
 use crate::{
     cli::compile_cmd::compile_circuit,
-    constants::{PROVER_INPUT_FILE, TARGET_DIR, WITNESS_EXT},
+    constants::{PROVER_INPUT_FILE, TARGET_DIR},
     errors::CliError,
 };
 
@@ -83,19 +82,3 @@ pub(crate) fn execute_program(
 
     Ok(solved_witness)
 }
-
-pub(crate) fn save_witness_to_dir<P: AsRef<Path>>(
-    witness: WitnessMap,
-    witness_name: &str,
-    witness_dir: P,
-) -> Result<PathBuf, CliError> {
-    let mut witness_path = create_named_dir(witness_dir.as_ref(), "witness");
-    witness_path.push(witness_name);
-    witness_path.set_extension(WITNESS_EXT);
-
-    let buf = Witness::to_bytes(&witness);
-
-    write_to_file(buf.as_slice(), &witness_path);
-
-    Ok(witness_path)
-}

crates/nargo/src/cli/fs/acir.rs

@@ -0,0 +1,29 @@
+use std::path::{Path, PathBuf};
+
+use acvm::{acir::circuit::Circuit, hash_constraint_system};
+
+use crate::constants::ACIR_EXT;
+
+use super::{create_named_dir, write_to_file};
+
+pub(crate) fn save_acir_to_dir<P: AsRef<Path>>(
+    circuit: &Circuit,
+    circuit_name: &str,
+    circuit_dir: P,
+) -> PathBuf {
+    let mut circuit_path = create_named_dir(circuit_dir.as_ref(), "target");
+    circuit_path.push(circuit_name);
+
+    let mut serialized = Vec::new();
+    circuit.write(&mut serialized).expect("could not serialize circuit");
+
+    circuit_path.set_extension(ACIR_EXT);
+    write_to_file(serialized.as_slice(), &circuit_path);
+
+    // Save a checksum of the circuit to compare against during proving and verification
+    let acir_hash = hash_constraint_system(circuit);
+    circuit_path.set_extension(ACIR_EXT.to_owned() + ".sha256");
+    write_to_file(hex::encode(acir_hash).as_bytes(), &circuit_path);
+
+    circuit_path
+}

crates/nargo/src/cli/fs/inputs.rs

@@ -0,0 +1,75 @@
+use noirc_abi::{
+    input_parser::{Format, InputValue},
+    Abi, InputMap, MAIN_RETURN_NAME,
+};
+use std::{collections::BTreeMap, path::Path};
+
+use crate::errors::CliError;
+
+use super::write_to_file;
+
+/// Returns the circuit's parameters and its return value, if one exists.
+/// # Examples
+///
+/// ```ignore
+/// let (input_map, return_value): (InputMap, Option<InputValue>) =
+///   read_inputs_from_file(path, "Verifier", Format::Toml, &abi)?;
+/// ```
+pub fn read_inputs_from_file<P: AsRef<Path>>(
+    path: P,
+    file_name: &str,
+    format: Format,
+    abi: &Abi,
+) -> Result<(InputMap, Option<InputValue>), CliError> {
+    if abi.is_empty() {
+        return Ok((BTreeMap::new(), None));
+    }
+
+    let file_path = {
+        let mut dir_path = path.as_ref().to_path_buf();
+        dir_path.push(file_name);
+        dir_path.set_extension(format.ext());
+        dir_path
+    };
+    if !file_path.exists() {
+        return Err(CliError::MissingTomlFile(file_name.to_owned(), file_path));
+    }
+
+    let input_string = std::fs::read_to_string(file_path).unwrap();
+    let mut input_map = format.parse(&input_string, abi)?;
+    let return_value = input_map.remove(MAIN_RETURN_NAME);
+
+    Ok((input_map, return_value))
+}
+
+pub fn write_inputs_to_file<P: AsRef<Path>>(
+    input_map: &InputMap,
+    return_value: &Option<InputValue>,
+    path: P,
+    file_name: &str,
+    format: Format,
+) -> Result<(), CliError> {
+    let file_path = {
+        let mut dir_path = path.as_ref().to_path_buf();
+        dir_path.push(file_name);
+        dir_path.set_extension(format.ext());
+        dir_path
+    };
+
+    // We must insert the return value into the `InputMap` in order for it to be written to file.
+    let serialized_output = match return_value {
+        // Parameters and return values are kept separate except for when they're being written to file.
+        // As a result, we don't want to modify the original map and must clone it before insertion.
+        Some(return_value) => {
+            let mut input_map = input_map.clone();
+            input_map.insert(MAIN_RETURN_NAME.to_owned(), return_value.clone());
+            format.serialize(&input_map)?
+        }
+        // If no return value exists, then we can serialize the original map directly.
+        None => format.serialize(input_map)?,
+    };
+
+    write_to_file(serialized_output.as_bytes(), &file_path);
+
+    Ok(())
+}

crates/nargo/src/cli/fs/keys.rs

@@ -0,0 +1,68 @@
+use std::path::{Path, PathBuf};
+
+use acvm::{acir::circuit::Circuit, hash_constraint_system};
+
+use crate::{
+    constants::{ACIR_EXT, PK_EXT, VK_EXT},
+    errors::CliError,
+};
+
+use super::{create_named_dir, load_hex_data, write_to_file};
+
+pub(crate) fn save_key_to_dir<P: AsRef<Path>>(
+    key: Vec<u8>,
+    key_name: &str,
+    key_dir: P,
+    is_proving_key: bool,
+) -> Result<PathBuf, CliError> {
+    let mut key_path = create_named_dir(key_dir.as_ref(), key_name);
+    key_path.push(key_name);
+    let extension = if is_proving_key { PK_EXT } else { VK_EXT };
+    key_path.set_extension(extension);
+
+    write_to_file(hex::encode(key).as_bytes(), &key_path);
+
+    Ok(key_path)
+}
+
+pub(crate) fn fetch_pk_and_vk<P: AsRef<Path>>(
+    circuit: &Circuit,
+    circuit_build_path: P,
+    prove_circuit: bool,
+    check_proof: bool,
+) -> Result<(Vec<u8>, Vec<u8>), CliError> {
+    let mut acir_hash_path = PathBuf::new();
+    acir_hash_path.push(circuit_build_path.as_ref());
+    acir_hash_path.set_extension(ACIR_EXT.to_owned() + ".sha256");
+    let expected_acir_hash = load_hex_data(acir_hash_path.clone())?;
+
+    let new_acir_hash = hash_constraint_system(circuit);
+
+    if new_acir_hash[..] != expected_acir_hash {
+        return Err(CliError::MismatchedAcir(acir_hash_path));
+    }
+
+    // This flag exists to avoid an unnecessary read of the proving key during verification
+    // as this method is used by both `nargo prove` and `nargo verify`
+    let proving_key = if prove_circuit {
+        let mut proving_key_path = PathBuf::new();
+        proving_key_path.push(circuit_build_path.as_ref());
+        proving_key_path.set_extension(PK_EXT);
+        load_hex_data(proving_key_path)?
+    } else {
+        // We can return an empty Vec here as `prove_circuit` should only be false when running `nargo verify`
+        vec![]
+    };
+
+    let verification_key = if check_proof {
+        let mut verification_key_path = PathBuf::new();
+        verification_key_path.push(circuit_build_path);
+        verification_key_path.set_extension(VK_EXT);
+        load_hex_data(verification_key_path)?
+    } else {
+        // We can return an empty Vec here as the verification key is used only is `check_proof` is true
+        vec![]
+    };
+
+    Ok((proving_key, verification_key))
+}

crates/nargo/src/cli/fs/mod.rs

@@ -0,0 +1,47 @@
+use std::{
+    fs::File,
+    io::Write,
+    path::{Path, PathBuf},
+};
+
+use crate::errors::CliError;
+
+pub mod acir;
+pub mod inputs;
+pub mod keys;
+pub mod proof;
+pub mod witness;
+
+fn create_dir<P: AsRef<Path>>(dir_path: P) -> Result<PathBuf, std::io::Error> {
+    let mut dir = std::path::PathBuf::new();
+    dir.push(dir_path);
+    std::fs::create_dir_all(&dir)?;
+    Ok(dir)
+}
+
+pub(crate) fn create_named_dir(named_dir: &Path, name: &str) -> PathBuf {
+    create_dir(named_dir).unwrap_or_else(|_| panic!("could not create the `{name}` directory"))
+}
+
+pub(crate) fn write_to_file(bytes: &[u8], path: &Path) -> String {
+    let display = path.display();
+
+    let mut file = match File::create(path) {
+        Err(why) => panic!("couldn't create {display}: {why}"),
+        Ok(file) => file,
+    };
+
+    match file.write_all(bytes) {
+        Err(why) => panic!("couldn't write to {display}: {why}"),
+        Ok(_) => display.to_string(),
+    }
+}
+
+pub fn load_hex_data<P: AsRef<Path>>(path: P) -> Result<Vec<u8>, CliError> {
+    let hex_data: Vec<_> =
+        std::fs::read(&path).map_err(|_| CliError::PathNotValid(path.as_ref().to_path_buf()))?;
+
+    let raw_bytes = hex::decode(hex_data).map_err(CliError::HexArtifactNotValid)?;
+
+    Ok(raw_bytes)
+}

crates/nargo/src/cli/fs/proof.rs

@@ -0,0 +1,19 @@
+use std::path::{Path, PathBuf};
+
+use crate::{constants::PROOF_EXT, errors::CliError};
+
+use super::{create_named_dir, write_to_file};
+
+pub(crate) fn save_proof_to_dir<P: AsRef<Path>>(
+    proof: &[u8],
+    proof_name: &str,
+    proof_dir: P,
+) -> Result<PathBuf, CliError> {
+    let mut proof_path = create_named_dir(proof_dir.as_ref(), "proof");
+    proof_path.push(proof_name);
+    proof_path.set_extension(PROOF_EXT);
+
+    write_to_file(hex::encode(proof).as_bytes(), &proof_path);
+
+    Ok(proof_path)
+}

crates/nargo/src/cli/fs/witness.rs

@@ -0,0 +1,23 @@
+use std::path::{Path, PathBuf};
+
+use acvm::acir::native_types::Witness;
+use noirc_abi::WitnessMap;
+
+use super::{create_named_dir, write_to_file};
+use crate::{constants::WITNESS_EXT, errors::CliError};
+
+pub(crate) fn save_witness_to_dir<P: AsRef<Path>>(
+    witness: WitnessMap,
+    witness_name: &str,
+    witness_dir: P,
+) -> Result<PathBuf, CliError> {
+    let mut witness_path = create_named_dir(witness_dir.as_ref(), "witness");
+    witness_path.push(witness_name);
+    witness_path.set_extension(WITNESS_EXT);
+
+    let buf = Witness::to_bytes(&witness);
+
+    write_to_file(buf.as_slice(), &witness_path);
+
+    Ok(witness_path)
+}