Validate label names

crates/pile-config/src/misc.rs

@@ -0,0 +1,122 @@
+use core::slice;
+use std::fmt::{Debug, Display};
+use std::ops::Deref;
+
+use serde::{Deserialize, Serialize};
+use smartstring::{LazyCompact, SmartString};
+
+#[derive(Debug, Clone, Deserialize)]
+#[serde(untagged)]
+pub enum OneOrMany<T: Debug + Clone> {
+	One(T),
+	Many(Vec<T>),
+}
+
+impl<T: Debug + Clone> OneOrMany<T> {
+	pub fn to_vec(self) -> Vec<T> {
+		match self {
+			Self::One(x) => vec![x],
+			Self::Many(x) => x,
+		}
+	}
+
+	pub fn as_slice(&self) -> &[T] {
+		match self {
+			Self::One(x) => slice::from_ref(&x),
+			Self::Many(x) => &x[..],
+		}
+	}
+}
+
+//
+// MARK: Label
+//
+
+/// A sanitized [String], guaranteed to only contain
+/// chars in `A-z`, `0-9`, and `-_`.
+///
+/// Used for names of datasets, fields, etc.
+#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Serialize, Deserialize)]
+#[serde(try_from = "String", into = "String")]
+pub struct Label(SmartString<LazyCompact>);
+
+impl Label {
+	pub const VALID_CHARS: &str =
+		"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-_";
+
+	pub fn new(str: impl Into<String>) -> Option<Self> {
+		let str: String = str.into();
+		for c in str.chars() {
+			if !Self::VALID_CHARS.contains(c) {
+				return None;
+			}
+		}
+
+		return Some(Self(str.into()));
+	}
+
+	pub fn as_str(&self) -> &str {
+		&self.0
+	}
+
+	pub fn into_string(self) -> String {
+		self.0.into()
+	}
+}
+
+impl Display for Label {
+	fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+		write!(f, "{}", self.0)
+	}
+}
+
+impl From<Label> for String {
+	fn from(value: Label) -> Self {
+		value.0.into()
+	}
+}
+
+impl TryFrom<String> for Label {
+	type Error = InvalidLabel;
+
+	fn try_from(value: String) -> Result<Self, Self::Error> {
+		Self::new(value).ok_or(InvalidLabel)
+	}
+}
+
+impl TryFrom<&str> for Label {
+	type Error = InvalidLabel;
+
+	fn try_from(value: &str) -> Result<Self, Self::Error> {
+		Self::new(value).ok_or(InvalidLabel)
+	}
+}
+
+impl AsRef<str> for Label {
+	fn as_ref(&self) -> &str {
+		&self.0
+	}
+}
+
+impl Deref for Label {
+	type Target = str;
+
+	fn deref(&self) -> &Self::Target {
+		&self.0
+	}
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub struct InvalidLabel;
+
+impl Display for InvalidLabel {
+	fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+		write!(
+			f,
+			"Invalid label: must only contain characters in {}",
+			Label::VALID_CHARS
+		)
+	}
+}
+
+impl std::error::Error for InvalidLabel {}