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/// An implementation to match on simple strings.
#[derive(Debug, Clone)]
#[allow(dead_code)]
pub enum Matcher {
/// Considers the entire string (trimmed) to be the match.
AllTrimmed,
/// After finding the `prefix` followed by one or more spaces, returns the following word.
PrefixedWord { prefix: &'static str },
/// Similar to `PrefixedWord`, but only if the word is a valid version.
PrefixedVersion { prefix: &'static str },
/// Takes a set of lines (separated by `\n`) and searches for the value in a key/value pair
/// separated by the `=` character. For example `VERSION_ID="8.1"`.
KeyValue { key: &'static str },
}
impl Matcher {
/// Find the match on the input `string`.
pub fn find(&self, string: &str) -> Option<String> {
match *self {
Self::AllTrimmed => Some(string.trim().to_string()),
Self::PrefixedWord { prefix } => find_prefixed_word(string, prefix).map(str::to_owned),
Self::PrefixedVersion { prefix } => find_prefixed_word(string, prefix)
.filter(|&v| is_valid_version(v))
.map(str::to_owned),
Self::KeyValue { key } => find_by_key(string, key).map(str::to_owned),
}
}
}
fn find_by_key<'a>(string: &'a str, key: &str) -> Option<&'a str> {
let key = [key, "="].concat();
for line in string.lines() {
if line.starts_with(&key) {
return Some(line[key.len()..].trim_matches(|c: char| c == '"' || c.is_whitespace()));
}
}
None
}
fn find_prefixed_word<'a>(string: &'a str, prefix: &str) -> Option<&'a str> {
if let Some(prefix_start) = string.find(prefix) {
// Ignore prefix and leading whitespace
let string = &string[prefix_start + prefix.len()..].trim_start();
// Find where the word boundary ends
let word_end = string
.find(|c: char| c.is_whitespace())
.unwrap_or(string.len());
let string = &string[..word_end];
Some(string)
} else {
None
}
}
fn is_valid_version(word: &str) -> bool {
!word.starts_with('.') && !word.ends_with('.')
}
#[cfg(test)]
mod tests {
use super::*;
use pretty_assertions::assert_eq;
#[test]
fn trimmed() {
let data = [
("", Some("")),
("test", Some("test")),
(" test", Some("test")),
("test ", Some("test")),
(" test ", Some("test")),
];
let matcher = Matcher::AllTrimmed;
for (input, expected) in &data {
let result = matcher.find(input);
assert_eq!(result.as_deref(), *expected);
}
}
#[test]
fn prefixed_word() {
let data = [
("", None),
("test", Some("")),
("test1", Some("1")),
("test 1", Some("1")),
(" test 1", Some("1")),
("test 1.2.3", Some("1.2.3")),
(" test 1.2.3", Some("1.2.3")),
];
let matcher = Matcher::PrefixedWord { prefix: "test" };
for (input, expected) in &data {
let result = matcher.find(input);
assert_eq!(result.as_deref(), *expected);
}
}
#[test]
fn prefixed_version() {
let data = [
("", None),
("test", Some("")),
("test 1", Some("1")),
("test .1", None),
("test 1.", None),
("test .1.", None),
(" test 1", Some("1")),
("test 1.2.3", Some("1.2.3")),
(" test 1.2.3", Some("1.2.3")),
];
let matcher = Matcher::PrefixedVersion { prefix: "test" };
for (input, expected) in &data {
let result = matcher.find(input);
assert_eq!(result.as_deref(), *expected);
}
}
#[test]
fn key_value() {
let data = [
("", None),
("key", None),
("key=value", Some("value")),
("key=1", Some("1")),
("key=\"1\"", Some("1")),
("key=\"CentOS Linux\"", Some("CentOS Linux")),
];
let matcher = Matcher::KeyValue { key: "key" };
for (input, expected) in &data {
let result = matcher.find(input);
assert_eq!(result.as_deref(), *expected);
}
}
}
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