Feature/watcher and cache

Cargo.toml

@@ -12,4 +12,8 @@ description = "An authorization library that supports access control models like
 regex = "1.3.1"
 rhai = "0.9.1"
 ip_network = "0.3.4"
+ttl_cache = "0.5.1"
+emitbrown = "0.1.8"
+lazy_static = "1.4.0"
 indexmap = "1.3.1"
+

README.md

@@ -23,7 +23,7 @@ Add this package to `Cargo.toml` of your project. (Check https://crates.io/crate
 
 ```toml
 [dependencies]
-casbin = "0.1.5"
+casbin = "0.1.6"
 ```
 
 ## Get started
@@ -36,7 +36,7 @@ use casbin::prelude::*;
 let model = Model::from_file("path/to/model.conf")?;
 let adapter = FileAdapter::new("path/to/policy.csv");
 
-let e = Enforcer::new(model, adapter);
+let e = Enforcer::new(model, adapter)?;
 ```
 
 2. Add an enforcement hook into your code right before the access happens:

src/adapter.rs

@@ -7,7 +7,7 @@ pub use memory_adapter::MemoryAdapter;
 use crate::model::Model;
 use crate::Result;
 
-pub trait Adapter {
+pub trait Adapter: Send + Sync {
     fn load_policy(&self, m: &mut Model) -> Result<()>;
     fn save_policy(&self, m: &mut Model) -> Result<()>;
     fn add_policy(&mut self, sec: &str, ptype: &str, rule: Vec<&str>) -> Result<bool>;

src/adapter/file_adapter.rs

@@ -37,7 +37,7 @@ impl<P: AsRef<Path>> FileAdapter<P> {
     }
 }
 
-impl<P: AsRef<Path>> Adapter for FileAdapter<P> {
+impl<P: AsRef<Path> + Send + Sync> Adapter for FileAdapter<P> {
     fn load_policy(&self, m: &mut Model) -> Result<()> {
         self.load_policy_file(m, load_policy_line)?;
         Ok(())

src/cached_enforcer.rs

@@ -0,0 +1,90 @@
+use crate::adapter::Adapter;
+use crate::emitter::{Event, CACHED_EMITTER};
+use crate::enforcer::Enforcer;
+use crate::model::Model;
+use crate::Result;
+
+use emitbrown::Events;
+use ttl_cache::TtlCache;
+
+use std::ops::{Deref, DerefMut};
+use std::time::Duration;
+
+pub struct CachedEnforcer {
+    pub(crate) ttl: Duration,
+    pub(crate) max_cached_items: usize,
+    pub(crate) enforcer: Enforcer,
+    pub(crate) cache: Option<TtlCache<Vec<String>, bool>>,
+}
+
+impl CachedEnforcer {
+    pub fn new(m: Model, a: Box<dyn Adapter>) -> Result<CachedEnforcer> {
+        let cached_enforcer = CachedEnforcer {
+            ttl: Duration::from_secs(120),
+            max_cached_items: 1000,
+            enforcer: Enforcer::new(m, a)?,
+            cache: None,
+        };
+
+        CACHED_EMITTER.lock().unwrap().on(
+            Event::PolicyChange,
+            Box::new(|ce: &mut CachedEnforcer| {
+                if let Some(ref mut cache) = ce.cache {
+                    cache.clear();
+                }
+            }),
+        );
+
+        Ok(cached_enforcer)
+    }
+
+    pub fn set_ttl(&mut self, ttl: Duration) {
+        self.ttl = ttl;
+    }
+
+    pub fn set_max_cached_items(&mut self, max_cached_items: usize) {
+        self.max_cached_items = max_cached_items;
+    }
+
+    pub fn enable_cache(&mut self) {
+        if self.cache.is_none() {
+            self.cache = Some(TtlCache::new(self.max_cached_items));
+        }
+    }
+
+    pub fn disable_cache(&mut self) {
+        if self.cache.is_some() {
+            self.cache = None;
+        }
+    }
+
+    pub fn enforce(&mut self, rvals: Vec<&str>) -> Result<bool> {
+        if let Some(ref mut cache) = self.cache {
+            let key: Vec<String> = rvals.iter().map(|&x| String::from(x)).collect();
+
+            if cache.contains_key(&key) {
+                Ok(*cache.get(&key).unwrap())
+            } else {
+                let result = self.enforcer.enforce(rvals)?;
+                cache.insert(key, result, self.ttl);
+                Ok(result)
+            }
+        } else {
+            self.enforcer.enforce(rvals)
+        }
+    }
+}
+
+impl Deref for CachedEnforcer {
+    type Target = Enforcer;
+
+    fn deref(&self) -> &Self::Target {
+        &self.enforcer
+    }
+}
+
+impl DerefMut for CachedEnforcer {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        &mut self.enforcer
+    }
+}

src/effector.rs

@@ -1,5 +1,5 @@
 pub trait Effector: Send + Sync {
-    fn merge_effects(&self, expr: String, effects: Vec<EffectKind>, results: Vec<f64>) -> bool;
+    fn merge_effects(&self, expr: String, effects: Vec<EffectKind>) -> bool;
 }
 
 #[derive(PartialEq, Clone)]
@@ -12,9 +12,8 @@ pub enum EffectKind {
 #[derive(Default)]
 pub struct DefaultEffector {}
 
-// TODO: can we remove results? seems to be useless
 impl Effector for DefaultEffector {
-    fn merge_effects(&self, expr: String, effects: Vec<EffectKind>, _results: Vec<f64>) -> bool {
+    fn merge_effects(&self, expr: String, effects: Vec<EffectKind>) -> bool {
         if expr == "some(where (p_eft == allow))" {
             let mut result = false;
             for eft in effects {

src/emitter.rs

@@ -0,0 +1,19 @@
+use crate::cached_enforcer::CachedEnforcer;
+use crate::enforcer::Enforcer;
+
+use emitbrown::Emitter;
+use lazy_static::lazy_static;
+
+use std::sync::Mutex;
+
+#[derive(Hash, PartialEq, Eq)]
+pub(crate) enum Event {
+    PolicyChange,
+}
+
+lazy_static! {
+    pub(crate) static ref EMITTER: Mutex<Emitter<'static, Event, Enforcer>> =
+        { Mutex::new(Emitter::new()) };
+    pub(crate) static ref CACHED_EMITTER: Mutex<Emitter<'static, Event, CachedEnforcer>> =
+        { Mutex::new(Emitter::new()) };
+}