Add unicode feature to switch between regex and regex-lite crates as a trade-off between full unicode support and binary size (#3291)

* - Add `unicode` feature to switch between `regex` and `regex-lite`

as a trade-off between full unicode support and binary size.

* Update CHANGES.md

* Update CHANGES.md

* refactor: move regexset code selection to own module

* docs: add docs within RegexSet module

* chore: restore manifests

* test: ensure all actix-router codepaths are tested

---------

Co-authored-by: Rob Ede <robjtede@icloud.com>

actix-router/CHANGES.md

@@ -2,6 +2,7 @@
 
 ## Unreleased
 
+- Add `unicode` crate feature (on-by-default) to switch between `regex` and `regex-lite` as a trade-off between full unicode support and binary size.
 - Minimum supported Rust version (MSRV) is now 1.72.
 
 ## 0.5.2

actix-router/Cargo.toml

@@ -17,12 +17,16 @@ name = "actix_router"
 path = "src/lib.rs"
 
 [features]
-default = ["http"]
+default = ["http", "unicode"]
+http = ["dep:http"]
+unicode = ["dep:regex"]
 
 [dependencies]
 bytestring = ">=0.1.5, <2"
+cfg-if = "1"
 http = { version = "0.2.7", optional = true }
-regex = "1.5"
+regex = { version = "1.5", optional = true }
+regex-lite = "0.1"
 serde = "1"
 tracing = { version = "0.1.30", default-features = false, features = ["log"] }
 
@@ -35,6 +39,7 @@ percent-encoding = "2.1"
 [[bench]]
 name = "router"
 harness = false
+required-features = ["unicode"]
 
 [[bench]]
 name = "quoter"

actix-router/src/lib.rs

@@ -10,6 +10,7 @@ mod de;
 mod path;
 mod pattern;
 mod quoter;
+mod regex_set;
 mod resource;
 mod resource_path;
 mod router;

actix-router/src/regex_set.rs

@@ -0,0 +1,66 @@
+//! Abstraction over `regex` and `regex-lite` depending on whether we have `unicode` crate feature
+//! enabled.
+
+use cfg_if::cfg_if;
+#[cfg(feature = "unicode")]
+pub(crate) use regex::{escape, Regex};
+#[cfg(not(feature = "unicode"))]
+pub(crate) use regex_lite::{escape, Regex};
+
+#[cfg(feature = "unicode")]
+#[derive(Debug, Clone)]
+pub(crate) struct RegexSet(regex::RegexSet);
+
+#[cfg(not(feature = "unicode"))]
+#[derive(Debug, Clone)]
+pub(crate) struct RegexSet(Vec<regex_lite::Regex>);
+
+impl RegexSet {
+    /// Create a new regex set.
+    ///
+    /// # Panics
+    ///
+    /// Panics if any path patterns are malformed.
+    pub(crate) fn new(re_set: Vec<String>) -> Self {
+        cfg_if! {
+            if #[cfg(feature = "unicode")] {
+                Self(regex::RegexSet::new(re_set).unwrap())
+            } else {
+                Self(re_set.iter().map(|re| Regex::new(re).unwrap()).collect())
+            }
+        }
+    }
+
+    /// Create a new empty regex set.
+    pub(crate) fn empty() -> Self {
+        cfg_if! {
+            if #[cfg(feature = "unicode")] {
+                Self(regex::RegexSet::empty())
+            } else {
+                Self(Vec::new())
+            }
+        }
+    }
+
+    /// Returns true if regex set matches `path`.
+    pub(crate) fn is_match(&self, path: &str) -> bool {
+        cfg_if! {
+            if #[cfg(feature = "unicode")] {
+                self.0.is_match(path)
+            } else {
+                self.0.iter().any(|re| re.is_match(path))
+            }
+        }
+    }
+
+    /// Returns index within `path` of first match.
+    pub(crate) fn first_match_idx(&self, path: &str) -> Option<usize> {
+        cfg_if! {
+            if #[cfg(feature = "unicode")] {
+                self.0.matches(path).into_iter().next()
+            } else {
+                Some(self.0.iter().enumerate().find(|(_, re)| re.is_match(path))?.0)
+            }
+        }
+    }
+}

actix-router/src/resource.rs

@@ -5,10 +5,13 @@ use std::{
     mem,
 };
 
-use regex::{escape, Regex, RegexSet};
 use tracing::error;
 
-use crate::{path::PathItem, IntoPatterns, Patterns, Resource, ResourcePath};
+use crate::{
+    path::PathItem,
+    regex_set::{escape, Regex, RegexSet},
+    IntoPatterns, Patterns, Resource, ResourcePath,
+};
 
 const MAX_DYNAMIC_SEGMENTS: usize = 16;
 
@@ -233,7 +236,7 @@ enum PatternSegment {
     Var(String),
 }
 
-#[derive(Clone, Debug)]
+#[derive(Debug, Clone)]
 #[allow(clippy::large_enum_variant)]
 enum PatternType {
     /// Single constant/literal segment.
@@ -603,7 +606,7 @@ impl ResourceDef {
             PatternType::Dynamic(re, _) => Some(re.captures(path)?[1].len()),
 
             PatternType::DynamicSet(re, params) => {
-                let idx = re.matches(path).into_iter().next()?;
+                let idx = re.first_match_idx(path)?;
                 let (ref pattern, _) = params[idx];
                 Some(pattern.captures(path)?[1].len())
             }
@@ -706,7 +709,7 @@ impl ResourceDef {
 
             PatternType::DynamicSet(re, params) => {
                 let path = path.unprocessed();
-                let (pattern, names) = match re.matches(path).into_iter().next() {
+                let (pattern, names) = match re.first_match_idx(path) {
                     Some(idx) => &params[idx],
                     _ => return false,
                 };
@@ -870,7 +873,7 @@ impl ResourceDef {
                     }
                 }
 
-                let pattern_re_set = RegexSet::new(re_set).unwrap();
+                let pattern_re_set = RegexSet::new(re_set);
                 let segments = segments.unwrap_or_default();
 
                 (