mirror of https://github.com/aya-rs/aya
lib: Add display hints
This change adds optional display hints:
* `{:x}`, `{:X}` - for hex representation of numbers
* `{:ipv4}`, `{:IPv4}` - for IPv4 addresses
* `{:ipv6}`, `{:IPv6}` - for IPv6 addresses
It also gets rid of dyn-fmt and instead comes with our own parser
implementation.
Tested on: https://github.com/vadorovsky/aya-examples/tree/main/tc
Signed-off-by: Michal Rostecki <vadorovsky@gmail.com>
pull/372/head
Michal Rostecki
2 years ago
committed by
Alessandro Decina
parent
944d6b8a16
commit
83ec27f06b
@ -0,0 +1,10 @@
|
||||
[package]
|
||||
name = "aya-log-parser"
|
||||
version = "0.1.11-dev.0"
|
||||
edition = "2018"
|
||||
|
||||
[dependencies]
|
||||
aya-log-common = { path = "../aya-log-common" }
|
||||
|
||||
[lib]
|
||||
path = "src/lib.rs"
|
||||
@ -0,0 +1,177 @@
|
||||
use std::str;
|
||||
|
||||
use aya_log_common::DisplayHint;
|
||||
|
||||
/// A parsed formatting parameter (contents of `{` `}` block).
|
||||
#[derive(Clone, Debug, PartialEq, Eq)]
|
||||
pub struct Parameter {
|
||||
/// The display hint, e.g. ':ipv4', ':x'.
|
||||
pub hint: DisplayHint,
|
||||
}
|
||||
|
||||
#[derive(Clone, Debug, PartialEq, Eq)]
|
||||
pub enum Fragment {
|
||||
/// A literal string (eg. `"literal "` in `"literal {}"`).
|
||||
Literal(String),
|
||||
|
||||
/// A format parameter.
|
||||
Parameter(Parameter),
|
||||
}
|
||||
|
||||
fn push_literal(frag: &mut Vec<Fragment>, unescaped_literal: &str) -> Result<(), String> {
|
||||
// Replace `{{` with `{` and `}}` with `}`. Single braces are errors.
|
||||
|
||||
// Scan for single braces first. The rest is trivial.
|
||||
let mut last_open = false;
|
||||
let mut last_close = false;
|
||||
for c in unescaped_literal.chars() {
|
||||
match c {
|
||||
'{' => last_open = !last_open,
|
||||
'}' => last_close = !last_close,
|
||||
_ => {
|
||||
if last_open {
|
||||
return Err("unmatched `{` in format string".into());
|
||||
}
|
||||
if last_close {
|
||||
return Err("unmatched `}` in format string".into());
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
// Handle trailing unescaped `{` or `}`.
|
||||
if last_open {
|
||||
return Err("unmatched `{` in format string".into());
|
||||
}
|
||||
if last_close {
|
||||
return Err("unmatched `}` in format string".into());
|
||||
}
|
||||
|
||||
let literal = unescaped_literal.replace("{{", "{").replace("}}", "}");
|
||||
frag.push(Fragment::Literal(literal));
|
||||
Ok(())
|
||||
}
|
||||
|
||||
/// Parses the display hint (e.g. the `ipv4` in `{:ipv4}`).
|
||||
fn parse_display_hint(s: &str) -> Result<DisplayHint, String> {
|
||||
Ok(match s {
|
||||
"x" => DisplayHint::LowerHex,
|
||||
"X" => DisplayHint::UpperHex,
|
||||
"ipv4" => DisplayHint::Ipv4,
|
||||
"ipv6" => DisplayHint::Ipv6,
|
||||
_ => return Err(format!("unknown display hint: {:?}", s)),
|
||||
})
|
||||
}
|
||||
|
||||
/// Parse `Param` from the given `&str` which can specify an optional format
|
||||
/// like `:x` or `:ipv4` (without curly braces, which are parsed by the `parse`
|
||||
/// function).
|
||||
fn parse_param(mut input: &str) -> Result<Parameter, String> {
|
||||
const HINT_PREFIX: &str = ":";
|
||||
|
||||
// Then, optional hint
|
||||
let mut hint = DisplayHint::Default;
|
||||
|
||||
if input.starts_with(HINT_PREFIX) {
|
||||
// skip the prefix
|
||||
input = &input[HINT_PREFIX.len()..];
|
||||
if input.is_empty() {
|
||||
return Err("malformed format string (missing display hint after ':')".into());
|
||||
}
|
||||
|
||||
hint = parse_display_hint(input)?;
|
||||
} else if !input.is_empty() {
|
||||
return Err(format!("unexpected content {:?} in format string", input));
|
||||
}
|
||||
|
||||
Ok(Parameter { hint })
|
||||
}
|
||||
|
||||
/// Parses the given format string into string literals and parameters specified
|
||||
/// by curly braces (with optional format hints like `:x` or `:ipv4`).
|
||||
pub fn parse(format_string: &str) -> Result<Vec<Fragment>, String> {
|
||||
let mut fragments = Vec::new();
|
||||
|
||||
// Index after the `}` of the last format specifier.
|
||||
let mut end_pos = 0;
|
||||
|
||||
let mut chars = format_string.char_indices();
|
||||
while let Some((brace_pos, ch)) = chars.next() {
|
||||
if ch != '{' {
|
||||
// Part of a literal fragment.
|
||||
continue;
|
||||
}
|
||||
|
||||
// Peek at the next char.
|
||||
if chars.as_str().starts_with('{') {
|
||||
// Escaped `{{`, also part of a literal fragment.
|
||||
chars.next();
|
||||
continue;
|
||||
}
|
||||
|
||||
if brace_pos > end_pos {
|
||||
// There's a literal fragment with at least 1 character before this
|
||||
// parameter fragment.
|
||||
let unescaped_literal = &format_string[end_pos..brace_pos];
|
||||
push_literal(&mut fragments, unescaped_literal)?;
|
||||
}
|
||||
|
||||
// Else, this is a format specifier. It ends at the next `}`.
|
||||
let len = chars
|
||||
.as_str()
|
||||
.find('}')
|
||||
.ok_or("missing `}` in format string")?;
|
||||
end_pos = brace_pos + 1 + len + 1;
|
||||
|
||||
// Parse the contents inside the braces.
|
||||
let param_str = &format_string[brace_pos + 1..][..len];
|
||||
let param = parse_param(param_str)?;
|
||||
fragments.push(Fragment::Parameter(param));
|
||||
}
|
||||
|
||||
// Trailing literal.
|
||||
if end_pos != format_string.len() {
|
||||
push_literal(&mut fragments, &format_string[end_pos..])?;
|
||||
}
|
||||
|
||||
Ok(fragments)
|
||||
}
|
||||
|
||||
#[cfg(test)]
|
||||
mod test {
|
||||
use super::*;
|
||||
|
||||
#[test]
|
||||
fn test_parse() {
|
||||
assert_eq!(
|
||||
parse("foo {} bar {:x} test {:X} ayy {:ipv4} lmao {:ipv6} {{}} {{something}}"),
|
||||
Ok(vec![
|
||||
Fragment::Literal("foo ".into()),
|
||||
Fragment::Parameter(Parameter {
|
||||
hint: DisplayHint::Default
|
||||
}),
|
||||
Fragment::Literal(" bar ".into()),
|
||||
Fragment::Parameter(Parameter {
|
||||
hint: DisplayHint::LowerHex
|
||||
}),
|
||||
Fragment::Literal(" test ".into()),
|
||||
Fragment::Parameter(Parameter {
|
||||
hint: DisplayHint::UpperHex
|
||||
}),
|
||||
Fragment::Literal(" ayy ".into()),
|
||||
Fragment::Parameter(Parameter {
|
||||
hint: DisplayHint::Ipv4
|
||||
}),
|
||||
Fragment::Literal(" lmao ".into()),
|
||||
Fragment::Parameter(Parameter {
|
||||
hint: DisplayHint::Ipv6
|
||||
}),
|
||||
Fragment::Literal(" {{}} {{something}}".into()),
|
||||
])
|
||||
);
|
||||
assert!(parse("foo {:}").is_err());
|
||||
assert!(parse("foo { bar").is_err());
|
||||
assert!(parse("foo } bar").is_err());
|
||||
assert!(parse("foo { bar }").is_err());
|
||||
}
|
||||
}
|
||||
Loading…
Reference in New Issue