tvl-depot/tvix/nix-compat/src/derivation/write.rs

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//! This module implements the serialisation of derivations into the
//! [ATerm][] format used by C++ Nix.
//!
//! [ATerm]: http://program-transformation.org/Tools/ATermFormat.html
use crate::derivation::escape::escape_bstr;
use crate::derivation::output::Output;
use bstr::BString;
use std::collections::BTreeSet;
use std::io::Cursor;
use std::{collections::BTreeMap, io, io::Error, io::Write};
pub const DERIVATION_PREFIX: &str = "Derive";
pub const PAREN_OPEN: char = '(';
pub const PAREN_CLOSE: char = ')';
pub const BRACKET_OPEN: char = '[';
pub const BRACKET_CLOSE: char = ']';
pub const COMMA: char = ',';
pub const QUOTE: char = '"';
// Writes a character to the writer.
pub(crate) fn write_char(writer: &mut impl Write, c: char) -> io::Result<()> {
let mut buf = [0; 4];
let b = c.encode_utf8(&mut buf).as_bytes();
io::copy(&mut Cursor::new(b), writer)?;
Ok(())
}
// Writes a string to the writer (as unicode)
pub(crate) fn write_str(writer: &mut impl Write, s: &str) -> io::Result<()> {
io::copy(&mut Cursor::new(s.as_bytes()), writer)?;
Ok(())
}
fn write_array_elements(
writer: &mut impl Write,
quote: bool,
open: &str,
closing: &str,
elements: &[BString],
) -> Result<(), io::Error> {
write_str(writer, open)?;
for (index, element) in elements.iter().enumerate() {
if index > 0 {
write_char(writer, COMMA)?;
}
if quote {
write_char(writer, QUOTE)?;
}
io::copy(&mut Cursor::new(element), writer)?;
if quote {
write_char(writer, QUOTE)?;
}
}
write_str(writer, closing)?;
Ok(())
}
pub fn write_outputs(
writer: &mut impl Write,
outputs: &BTreeMap<String, Output>,
) -> Result<(), io::Error> {
write_char(writer, BRACKET_OPEN)?;
for (ii, (output_name, output)) in outputs.iter().enumerate() {
if ii > 0 {
write_char(writer, COMMA)?;
}
let mut elements: Vec<BString> = vec![
output_name.as_bytes().to_vec().into(),
output.path.as_bytes().to_vec().into(),
];
let (e2, e3) = match &output.hash_with_mode {
Some(hash) => match hash {
crate::nixhash::NixHashWithMode::Flat(h) => (
h.algo.to_string().as_bytes().to_vec(),
data_encoding::HEXLOWER.encode(&h.digest).as_bytes().into(),
),
crate::nixhash::NixHashWithMode::Recursive(h) => (
format!("r:{}", h.algo).as_bytes().to_vec(),
data_encoding::HEXLOWER.encode(&h.digest).as_bytes().into(),
),
},
None => (vec![], vec![]),
};
elements.push(e2.into());
elements.push(e3.into());
write_array_elements(
writer,
true,
&PAREN_OPEN.to_string(),
&PAREN_CLOSE.to_string(),
&elements,
)?
}
write_char(writer, BRACKET_CLOSE)?;
Ok(())
}
pub fn write_input_derivations(
writer: &mut impl Write,
input_derivations: &BTreeMap<String, BTreeSet<String>>,
) -> Result<(), io::Error> {
write_char(writer, COMMA)?;
write_char(writer, BRACKET_OPEN)?;
for (ii, (input_derivation_path, input_derivation)) in input_derivations.into_iter().enumerate()
{
if ii > 0 {
write_char(writer, COMMA)?;
}
write_char(writer, PAREN_OPEN)?;
write_char(writer, QUOTE)?;
write_str(writer, input_derivation_path.as_str())?;
write_char(writer, QUOTE)?;
write_char(writer, COMMA)?;
write_array_elements(
writer,
true,
&BRACKET_OPEN.to_string(),
&BRACKET_CLOSE.to_string(),
&input_derivation
.iter()
.map(|s| s.as_bytes().to_vec().into())
.collect::<Vec<BString>>(),
)?;
write_char(writer, PAREN_CLOSE)?;
}
write_char(writer, BRACKET_CLOSE)?;
Ok(())
}
pub fn write_input_sources(
writer: &mut impl Write,
input_sources: &BTreeSet<String>,
) -> Result<(), io::Error> {
write_char(writer, COMMA)?;
write_array_elements(
writer,
true,
&BRACKET_OPEN.to_string(),
&BRACKET_CLOSE.to_string(),
&input_sources
.iter()
.map(|s| s.as_bytes().to_vec().into())
.collect::<Vec<BString>>(),
)?;
Ok(())
}
pub fn write_system(writer: &mut impl Write, platform: &str) -> Result<(), Error> {
write_char(writer, COMMA)?;
io::copy(&mut Cursor::new(escape_bstr(platform.as_bytes())), writer)?;
Ok(())
}
pub fn write_builder(writer: &mut impl Write, builder: &str) -> Result<(), Error> {
write_char(writer, COMMA)?;
io::copy(&mut Cursor::new(escape_bstr(builder.as_bytes())), writer)?;
Ok(())
}
pub fn write_arguments(writer: &mut impl Write, arguments: &[String]) -> Result<(), io::Error> {
write_char(writer, COMMA)?;
write_array_elements(
writer,
true,
&BRACKET_OPEN.to_string(),
&BRACKET_CLOSE.to_string(),
&arguments
.iter()
.map(|s| s.as_bytes().to_vec().into())
.collect::<Vec<BString>>(),
)?;
Ok(())
}
pub fn write_enviroment(
writer: &mut impl Write,
environment: &BTreeMap<String, BString>,
) -> Result<(), io::Error> {
write_char(writer, COMMA)?;
write_char(writer, BRACKET_OPEN)?;
for (i, (k, v)) in environment.into_iter().enumerate() {
if i > 0 {
write_char(writer, COMMA)?;
}
write_array_elements(
writer,
false,
&PAREN_OPEN.to_string(),
&PAREN_CLOSE.to_string(),
&[escape_bstr(k.as_bytes()), escape_bstr(v)],
)?;
}
write_char(writer, BRACKET_CLOSE)?;
Ok(())
}