51 lines
1.7 KiB
Rust
51 lines
1.7 KiB
Rust
//! Reading and parsing the arguments `brokerd` puts on `toolkit`'s standard input.
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use std::io::Read;
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pub const MAX_INPUT: usize = 2 * 1024 * 1024;
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#[derive(Debug)]
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pub enum InputError {
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TooLarge,
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NotUtf8,
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Io(std::io::Error),
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}
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impl std::fmt::Display for InputError {
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fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
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match self {
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InputError::TooLarge => write!(f, "the arguments are larger than {MAX_INPUT} bytes"),
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InputError::NotUtf8 => write!(f, "the arguments are not UTF-8"),
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InputError::Io(e) => write!(f, "cannot read the arguments: {e}"),
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}
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}
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}
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impl std::error::Error for InputError {}
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impl From<std::io::Error> for InputError {
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fn from(e: std::io::Error) -> Self {
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InputError::Io(e)
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}
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}
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/// All of `stdin`, at most MAX_INPUT bytes, as UTF-8. Read at most MAX_INPUT + 1 bytes
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/// (`Read::take`); more than MAX_INPUT is TooLarge.
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pub fn read_input(stdin: &mut dyn std::io::Read) -> Result<String, InputError> {
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let mut buf = Vec::new();
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let n = stdin
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.take(u64::try_from(MAX_INPUT).map_or(u64::MAX, |n| n.saturating_add(1)))
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.read_to_end(&mut buf)?;
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if n > MAX_INPUT {
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return Err(InputError::TooLarge);
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}
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String::from_utf8(buf).map_err(|_| InputError::NotUtf8)
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}
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/// Parse `text` as the arguments of tool `name`; the error is the whole line for stderr:
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/// "toolkit: {name}: the arguments do not parse: {serde's error}".
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pub fn parse<T: serde::de::DeserializeOwned>(name: &str, text: &str) -> Result<T, String> {
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serde_json::from_str(text)
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.map_err(|e| format!("toolkit: {name}: the arguments do not parse: {e}"))
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}
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