Move escaping algorithm into a separate module

askama_shared/src/escaping.rs

@@ -0,0 +1,50 @@
+fn escapable(b: &u8) -> bool {
+    *b == b'<' || *b == b'>' || *b == b'&'
+}
+
+pub fn escape(s: String) -> String {
+    let mut found = Vec::new();
+    for (i, b) in s.as_bytes().iter().enumerate() {
+        if escapable(b) {
+            found.push(i);
+        }
+    }
+    if found.is_empty() {
+        return s;
+    }
+
+    let bytes = s.as_bytes();
+    let max_len = bytes.len() + found.len() * 3;
+    let mut res = Vec::<u8>::with_capacity(max_len);
+    let mut start = 0;
+    for idx in &found {
+        if start < *idx {
+            res.extend(&bytes[start..*idx]);
+        }
+        start = *idx + 1;
+        match bytes[*idx] {
+            b'<' => { res.extend(b"&lt;"); },
+            b'>' => { res.extend(b"&gt;"); },
+            b'&' => { res.extend(b"&amp;"); },
+            _ => panic!("incorrect indexing"),
+        }
+    }
+    if start < bytes.len() - 1 {
+        res.extend(&bytes[start..]);
+    }
+
+    String::from_utf8(res).unwrap()
+}
+
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    #[test]
+    fn test_escape() {
+        assert_eq!(escape("".to_string()), "");
+        assert_eq!(escape("<&>".to_string()), "&lt;&amp;&gt;");
+        assert_eq!(escape("bla&".to_string()), "bla&amp;");
+        assert_eq!(escape("<foo".to_string()), "&lt;foo");
+    }
+}

askama_shared/src/filters/mod.rs

@@ -13,6 +13,7 @@ pub use self::json::json;
 
 use std::fmt;
 
+use escaping;
 use super::Result;
 
 
@@ -33,44 +34,10 @@ pub const BUILT_IN_FILTERS: [&str; 9] = [
 ];
 
 
-fn escapable(b: &u8) -> bool {
-    *b == b'<' || *b == b'>' || *b == b'&'
-}
-
 /// Escapes `&`, `<` and `>` in strings
 pub fn escape(s: &fmt::Display) -> Result<String> {
     let s = format!("{}", s);
-    let mut found = Vec::new();
+    Ok(escaping::escape(s))
-    for (i, b) in s.as_bytes().iter().enumerate() {
-        if escapable(b) {
-            found.push(i);
-        }
-    }
-    if found.is_empty() {
-        return Ok(s);
-    }
-
-    let bytes = s.as_bytes();
-    let max_len = bytes.len() + found.len() * 3;
-    let mut res = Vec::<u8>::with_capacity(max_len);
-    let mut start = 0;
-    for idx in &found {
-        if start < *idx {
-            res.extend(&bytes[start..*idx]);
-        }
-        start = *idx + 1;
-        match bytes[*idx] {
-            b'<' => { res.extend(b"&lt;"); },
-            b'>' => { res.extend(b"&gt;"); },
-            b'&' => { res.extend(b"&amp;"); },
-            _ => panic!("incorrect indexing"),
-        }
-    }
-    if start < bytes.len() - 1 {
-        res.extend(&bytes[start..]);
-    }
-
-    Ok(String::from_utf8(res).unwrap())
 }
 
 /// Alias for the `escape()` filter
@@ -135,17 +102,10 @@ pub fn join<T, I, S>(input: I, separator: S) -> Result<String>
     Ok(rv)
 }
 
+
 #[cfg(test)]
 mod tests {
     use super::*;
-    #[test]
-    fn test_escape() {
-        assert_eq!(escape(&"").unwrap(), "");
-        assert_eq!(escape(&"<&>").unwrap(), "&lt;&amp;&gt;");
-        assert_eq!(escape(&"bla&").unwrap(), "bla&amp;");
-        assert_eq!(escape(&"<foo").unwrap(), "&lt;foo");
-    }
-
     #[test]
     fn test_lower() {
         assert_eq!(lower(&"Foo").unwrap(), "foo");

askama_shared/src/lib.rs

@@ -16,6 +16,7 @@ pub mod path;
 pub use parser::parse;
 pub use generator::generate;
 
+mod escaping;
 mod generator;
 mod parser;