add str traits for split, between, unquote; consolidate tests

Signed-off-by: Jason Volk <jason@zemos.net>

src/core/utils/string.rs

@@ -1,3 +1,10 @@
+mod between;
+mod split;
+mod tests;
+mod unquote;
+mod unquoted;
+
+pub use self::{between::Between, split::SplitInfallible, unquote::Unquote, unquoted::Unquoted};
 use crate::{utils::exchange, Result};
 
 pub const EMPTY: &str = "";
@@ -95,12 +102,6 @@ pub fn common_prefix<'a>(choice: &'a [&str]) -> &'a str {
 	})
 }
 
-#[inline]
-#[must_use]
-pub fn split_once_infallible<'a>(input: &'a str, delim: &'_ str) -> (&'a str, &'a str) {
-	input.split_once(delim).unwrap_or((input, EMPTY))
-}
-
 /// Parses the bytes into a string.
 pub fn string_from_bytes(bytes: &[u8]) -> Result<String> {
 	let str: &str = str_from_bytes(bytes)?;

src/core/utils/string/between.rs

@@ -0,0 +1,26 @@
+type Delim<'a> = (&'a str, &'a str);
+
+/// Slice a string between a pair of delimeters.
+pub trait Between<'a> {
+	/// Extract a string between the delimeters. If the delimeters were not
+	/// found None is returned, otherwise the first extraction is returned.
+	fn between(&self, delim: Delim<'_>) -> Option<&'a str>;
+
+	/// Extract a string between the delimeters. If the delimeters were not
+	/// found the original string is returned; take note of this behavior,
+	/// if an empty slice is desired for this case use the fallible version and
+	/// unwrap to EMPTY.
+	fn between_infallible(&self, delim: Delim<'_>) -> &'a str;
+}
+
+impl<'a> Between<'a> for &'a str {
+	#[inline]
+	fn between_infallible(&self, delim: Delim<'_>) -> &'a str { self.between(delim).unwrap_or(self) }
+
+	#[inline]
+	fn between(&self, delim: Delim<'_>) -> Option<&'a str> {
+		self.split_once(delim.0)
+			.and_then(|(_, b)| b.rsplit_once(delim.1))
+			.map(|(a, _)| a)
+	}
+}

src/core/utils/string/split.rs

@@ -0,0 +1,22 @@
+use super::EMPTY;
+
+type Pair<'a> = (&'a str, &'a str);
+
+/// Split a string with default behaviors on non-match.
+pub trait SplitInfallible<'a> {
+	/// Split a string at the first occurrence of delim. If not found, the
+	/// entire string is returned in \[0\], while \[1\] is empty.
+	fn split_once_infallible(&self, delim: &str) -> Pair<'a>;
+
+	/// Split a string from the last occurrence of delim. If not found, the
+	/// entire string is returned in \[0\], while \[1\] is empty.
+	fn rsplit_once_infallible(&self, delim: &str) -> Pair<'a>;
+}
+
+impl<'a> SplitInfallible<'a> for &'a str {
+	#[inline]
+	fn rsplit_once_infallible(&self, delim: &str) -> Pair<'a> { self.rsplit_once(delim).unwrap_or((self, EMPTY)) }
+
+	#[inline]
+	fn split_once_infallible(&self, delim: &str) -> Pair<'a> { self.split_once(delim).unwrap_or((self, EMPTY)) }
+}

src/core/utils/string/tests.rs

@@ -0,0 +1,70 @@
+#![cfg(test)]
+
+#[test]
+fn common_prefix() {
+	let input = ["conduwuit", "conduit", "construct"];
+	let output = super::common_prefix(&input);
+	assert_eq!(output, "con");
+}
+
+#[test]
+fn common_prefix_empty() {
+	let input = ["abcdefg", "hijklmn", "opqrstu"];
+	let output = super::common_prefix(&input);
+	assert_eq!(output, "");
+}
+
+#[test]
+fn common_prefix_none() {
+	let input = [];
+	let output = super::common_prefix(&input);
+	assert_eq!(output, "");
+}
+
+#[test]
+fn camel_to_snake_case_0() {
+	let res = super::camel_to_snake_string("CamelToSnakeCase");
+	assert_eq!(res, "camel_to_snake_case");
+}
+
+#[test]
+fn camel_to_snake_case_1() {
+	let res = super::camel_to_snake_string("CAmelTOSnakeCase");
+	assert_eq!(res, "camel_tosnake_case");
+}
+
+#[test]
+fn unquote() {
+	use super::Unquote;
+
+	assert_eq!("\"foo\"".unquote(), Some("foo"));
+	assert_eq!("\"foo".unquote(), None);
+	assert_eq!("foo".unquote(), None);
+}
+
+#[test]
+fn unquote_infallible() {
+	use super::Unquote;
+
+	assert_eq!("\"foo\"".unquote_infallible(), "foo");
+	assert_eq!("\"foo".unquote_infallible(), "\"foo");
+	assert_eq!("foo".unquote_infallible(), "foo");
+}
+
+#[test]
+fn between() {
+	use super::Between;
+
+	assert_eq!("\"foo\"".between(("\"", "\"")), Some("foo"));
+	assert_eq!("\"foo".between(("\"", "\"")), None);
+	assert_eq!("foo".between(("\"", "\"")), None);
+}
+
+#[test]
+fn between_infallible() {
+	use super::Between;
+
+	assert_eq!("\"foo\"".between_infallible(("\"", "\"")), "foo");
+	assert_eq!("\"foo".between_infallible(("\"", "\"")), "\"foo");
+	assert_eq!("foo".between_infallible(("\"", "\"")), "foo");
+}

src/core/utils/string/unquote.rs

@@ -0,0 +1,33 @@
+const QUOTE: char = '"';
+
+/// Slice a string between quotes
+pub trait Unquote<'a> {
+	/// Whether the input is quoted. If this is false the fallible methods of
+	/// this interface will fail.
+	fn is_quoted(&self) -> bool;
+
+	/// Unquotes a string. If the input is not quoted it is simply returned
+	/// as-is. If the input is partially quoted on either end that quote is not
+	/// removed.
+	fn unquote(&self) -> Option<&'a str>;
+
+	/// Unquotes a string. The input must be quoted on each side for Some to be
+	/// returned
+	fn unquote_infallible(&self) -> &'a str;
+}
+
+impl<'a> Unquote<'a> for &'a str {
+	#[inline]
+	fn unquote_infallible(&self) -> &'a str {
+		self.strip_prefix(QUOTE)
+			.unwrap_or(self)
+			.strip_suffix(QUOTE)
+			.unwrap_or(self)
+	}
+
+	#[inline]
+	fn unquote(&self) -> Option<&'a str> { self.strip_prefix(QUOTE).and_then(|s| s.strip_suffix(QUOTE)) }
+
+	#[inline]
+	fn is_quoted(&self) -> bool { self.starts_with(QUOTE) && self.ends_with(QUOTE) }
+}

src/core/utils/string/unquoted.rs

@@ -0,0 +1,52 @@
+use std::ops::Deref;
+
+use serde::{de, Deserialize, Deserializer};
+
+use super::Unquote;
+use crate::{err, Result};
+
+/// Unquoted string which deserialized from a quoted string. Construction from a
+/// &str is infallible such that the input can already be unquoted. Construction
+/// from serde deserialization is fallible and the input must be quoted.
+#[repr(transparent)]
+pub struct Unquoted(str);
+
+impl<'a> Unquoted {
+	#[inline]
+	#[must_use]
+	pub fn as_str(&'a self) -> &'a str { &self.0 }
+}
+
+impl<'a, 'de: 'a> Deserialize<'de> for &'a Unquoted {
+	fn deserialize<D: Deserializer<'de>>(deserializer: D) -> Result<Self, D::Error> {
+		let s = <&'a str>::deserialize(deserializer)?;
+		s.is_quoted()
+			.then_some(s)
+			.ok_or(err!(SerdeDe("expected quoted string")))
+			.map_err(de::Error::custom)
+			.map(Into::into)
+	}
+}
+
+impl<'a> From<&'a str> for &'a Unquoted {
+	fn from(s: &'a str) -> &'a Unquoted {
+		let s: &'a str = s.unquote_infallible();
+
+		//SAFETY: This is a pattern I lifted from ruma-identifiers for strong-type strs
+		// by wrapping in a tuple-struct.
+		#[allow(clippy::transmute_ptr_to_ptr)]
+		unsafe {
+			std::mem::transmute(s)
+		}
+	}
+}
+
+impl Deref for Unquoted {
+	type Target = str;
+
+	fn deref(&self) -> &Self::Target { &self.0 }
+}
+
+impl<'a> AsRef<str> for &'a Unquoted {
+	fn as_ref(&self) -> &'a str { &self.0 }
+}

src/core/utils/tests.rs

@@ -36,33 +36,6 @@ fn increment_wrap() {
 	assert_eq!(res, 0);
 }
 
-#[test]
-fn common_prefix() {
-	use utils::string;
-
-	let input = ["conduwuit", "conduit", "construct"];
-	let output = string::common_prefix(&input);
-	assert_eq!(output, "con");
-}
-
-#[test]
-fn common_prefix_empty() {
-	use utils::string;
-
-	let input = ["abcdefg", "hijklmn", "opqrstu"];
-	let output = string::common_prefix(&input);
-	assert_eq!(output, "");
-}
-
-#[test]
-fn common_prefix_none() {
-	use utils::string;
-
-	let input = [];
-	let output = string::common_prefix(&input);
-	assert_eq!(output, "");
-}
-
 #[test]
 fn checked_add() {
 	use crate::checked;
@@ -134,19 +107,3 @@ async fn mutex_map_contend() {
 	tokio::try_join!(join_b, join_a).expect("joined");
 	assert!(map.is_empty(), "Must be empty");
 }
-
-#[test]
-fn camel_to_snake_case_0() {
-	use utils::string::camel_to_snake_string;
-
-	let res = camel_to_snake_string("CamelToSnakeCase");
-	assert_eq!(res, "camel_to_snake_case");
-}
-
-#[test]
-fn camel_to_snake_case_1() {
-	use utils::string::camel_to_snake_string;
-
-	let res = camel_to_snake_string("CAmelTOSnakeCase");
-	assert_eq!(res, "camel_tosnake_case");
-}