Use internal implementation of HTML escaping

3 files changed, 47 insertions, 11 deletions

diff --git a/Cargo.lock b/Cargo.lock
index 4296551..6e26567 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -10,7 +10,6 @@ dependencies = [
 name = "askama"
 version = "0.1.0"
 dependencies = [
- "htmlescape 0.3.1 (git+https://github.com/veddan/rust-htmlescape)",
  "nom 2.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "syn 0.11.4 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -24,11 +23,6 @@ dependencies = [
 ]
 
 [[package]]
-name = "htmlescape"
-version = "0.3.1"
-source = "git+https://github.com/veddan/rust-htmlescape#1699b539179798e705ad8464128492a0a0092876"
-
-[[package]]
 name = "nom"
 version = "2.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -53,7 +47,6 @@ version = "0.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [metadata]
-"checksum htmlescape 0.3.1 (git+https://github.com/veddan/rust-htmlescape)" = "<none>"
 "checksum nom 2.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "e5d4598834859fedb9a0a69d5b862a970e77982a92f544d547257a4d49469067"
 "checksum quote 0.3.12 (registry+https://github.com/rust-lang/crates.io-index)" = "e7b44fd83db28b83c1c58187159934906e5e955c812e211df413b76b03c909a5"
 "checksum syn 0.11.4 (registry+https://github.com/rust-lang/crates.io-index)" = "f4f94368aae82bb29656c98443a7026ca931a659e8d19dcdc41d6e273054e820"
diff --git a/askama/Cargo.toml b/askama/Cargo.toml
index 55c6059..2f28018 100644
--- a/askama/Cargo.toml
+++ b/askama/Cargo.toml
@@ -8,6 +8,5 @@ license = "MIT/Apache-2.0"
 workspace = ".."
 
 [dependencies]
-htmlescape = { git = "https://github.com/veddan/rust-htmlescape" }
 nom = "2.1"
 syn = "0.11"
diff --git a/askama/src/filters.rs b/askama/src/filters.rs
index 08feed3..fd8222c 100644
--- a/askama/src/filters.rs
+++ b/askama/src/filters.rs
@@ -1,8 +1,52 @@
-extern crate htmlescape;
-
 use std::fmt;
 
+fn escapable(b: &u8) -> bool {
+    *b == b'<' || *b == b'>' || *b == b'&'
+}
+
 pub fn e(s: &fmt::Display) -> String {
     let s = format!("{}", s);
-    htmlescape::encode_minimal(&s)
+    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::e;
+    #[test]
+    fn test_escape() {
+        assert_eq!(e(&""), "");
+        assert_eq!(e(&"<&>"), "&lt;&amp;&gt;");
+        assert_eq!(e(&"bla&"), "bla&amp;");
+        assert_eq!(e(&"<foo"), "&lt;foo");
+    }
 }