Implement glob builtins

crates/burrego/src/opa/builtins/glob.rs

@@ -0,0 +1,46 @@
+use anyhow::{anyhow, Result};
+
+pub fn quote_meta(args: &[serde_json::Value]) -> Result<serde_json::Value> {
+    if args.len() != 1 {
+        return Err(anyhow!("glob.quote_meta: wrong number of arguments"));
+    }
+
+    let input = args[0]
+        .as_str()
+        .ok_or_else(|| anyhow!("glob.quote_meta: 1st parameter is not a string"))?;
+
+    serde_json::to_value(escape(input))
+        .map_err(|e| anyhow!("glob.quote_meta: cannot convert value into JSON: {:?}", e))
+}
+
+fn escape(s: &str) -> String {
+    let mut escaped = String::new();
+    for c in s.chars() {
+        match c {
+            '*' | '?' | '\\' | '[' | ']' | '{' | '}' => {
+                escaped.push('\\');
+                escaped.push(c);
+            }
+            c => {
+                escaped.push(c);
+            }
+        }
+    }
+    escaped
+}
+
+#[cfg(test)]
+mod test {
+    #[test]
+    fn escape() {
+        assert_eq!(super::escape("*.domain.com"), r"\*.domain.com",);
+
+        assert_eq!(super::escape("*.domain-*.com"), r"\*.domain-\*.com",);
+
+        assert_eq!(super::escape("domain.com"), r"domain.com",);
+
+        assert_eq!(super::escape("domain-[ab].com"), r"domain-\[ab\].com",);
+
+        assert_eq!(super::escape("nie?ce"), r"nie\?ce",);
+    }
+}

crates/burrego/src/opa/builtins/mod.rs

@@ -2,14 +2,14 @@ use anyhow::Result;
 use std::collections::HashMap;
 
 pub mod encoding;
+pub mod glob;
 pub mod strings;
 
 pub type BuiltinFunctionsMap =
     HashMap<&'static str, fn(&[serde_json::Value]) -> Result<serde_json::Value>>;
 
 pub fn get_builtins() -> BuiltinFunctionsMap {
     let mut functions: BuiltinFunctionsMap = HashMap::new();
-    functions.insert("sprintf", strings::sprintf);
 
     // encoding
     functions.insert(
@@ -26,5 +26,11 @@ pub fn get_builtins() -> BuiltinFunctionsMap {
     functions.insert("hex.encode", encoding::hex::encode);
     functions.insert("hex.decode", encoding::hex::decode);
 
+    // glob
+    functions.insert("glob.quote_meta", glob::quote_meta);
+
+    // strings
+    functions.insert("sprintf", strings::sprintf);
+
     functions
 }

src/policy_evaluator.rs

@@ -1,6 +1,6 @@
 use anyhow::{anyhow, Result};
 use serde::Serialize;
-use serde_json::{json, value};
+use serde_json::value;
 use std::{
     convert::{TryFrom, TryInto},
     fmt, fs,
@@ -235,6 +235,7 @@ impl PolicyEvaluator {
 mod tests {
     use super::*;
 
+    use serde_json::json;
     use std::collections::HashMap;
 
     #[test]