Adapt to discussion in bytecodealliance/wasmtime-dotnet#90

christophwille · Feb 1, 2022 · ad1f6e6 · ad1f6e6
1 parent d490f51
commit ad1f6e6
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Showing 2 changed files with 13 additions and 43 deletions.
diff --git a/spikes/HigherLevelApisSpike/IPolicyFactory.cs b/spikes/HigherLevelApisSpike/IPolicyFactory.cs
@@ -7,20 +7,12 @@ namespace HigherLevelApisSpike;
 public class Policy : IDisposable
 {
     private bool disposedValue;
-
-    internal Module? _module;
-    internal string _policyName;
     private readonly IOpaSerializer _serde;
-
     public OpaPolicy Opa { get; }
 
-    public Policy(OpaPolicy opaPolicy, Module module, string policyName, IOpaSerializer serde)
+    public Policy(OpaPolicy opaPolicy, IOpaSerializer serde)
     {
         Opa = opaPolicy;
-
-        _module = module;
-        _policyName = policyName;
-
         _serde = serde;
     }
 
@@ -40,16 +32,8 @@ protected virtual void Dispose(bool disposing)
         {
             if (disposing)
             {
-                // TODO: dispose managed state (managed objects)
-
-                // When disposing, we are not telling the PolicyFactory
                 Opa.Dispose();
-                if (null != _module) _module.Dispose();
-                _module = null;
             }
-
-            // TODO: free unmanaged resources (unmanaged objects) and override finalizer
-            // TODO: set large fields to null
             disposedValue = true;
         }
     }
@@ -94,19 +78,19 @@ public string Serialize(object obj)
 }
 
 // Size of module cache is determined by implementation
-public interface IModuleCache
+public interface IOpaModuleCache
 {
-    public Module? GetAndRemove(string policyName);
+    public Module? Get(string policyName);
     public void Add(string policyName, Module module);
 }
 
-public class NoOpModuleCache : IModuleCache
+public class NoOpModuleCache : IOpaModuleCache
 {
     public void Add(string policyName, Module module)
     {
     }
 
-    public Module? GetAndRemove(string policyName)
+    public Module? Get(string policyName)
     {
         return null;
     }
@@ -116,47 +100,34 @@ public class PolicyFactory
 {
     private readonly IPolicyStore _store;
     private readonly IOpaSerializer _serde;
-    private readonly IModuleCache _moduleCache;
+    private readonly IOpaModuleCache _moduleCache;
 
-    public PolicyFactory(IPolicyStore store, IModuleCache moduleCache, IOpaSerializer serde)
+    public PolicyFactory(IPolicyStore store, IOpaModuleCache moduleCache, IOpaSerializer serde)
     {
         _store = store;
         _serde = serde;
         _moduleCache = moduleCache;
     }
 
-    // Idea from ArrayPool
-    public async Task<Policy> RentAsync(string policyName)
+    public async Task<Policy> GetAsync(string policyName)
     {
         using var opaRuntime = new OpaRuntime();
 
         Module? module = null;
-        if (null == (module = _moduleCache.GetAndRemove(policyName)))
+        if (null == (module = _moduleCache.Get(policyName)))
         {
             // Non-cache case
             var (wasmBytes, err) = await _store.LoadPolicyAsync(policyName);
 
             // disposing is the duty of the consumer
             module = opaRuntime.Load(policyName, wasmBytes);
+
+            _moduleCache.Add(policyName, module);
         }
 
         // disposing is the duty of the consumer
         var opaPolicy = new OpaPolicy(opaRuntime, module);
 
-        return new Policy(opaPolicy, module, policyName, _serde);
-    }
-
-    // intentionally void because the cache if any is going to be on the local machine!
-    public void Return(Policy p)
-    {
-        var moduleToReturn = p._module;
-        if (null == moduleToReturn) return;
-
-        p._module = null;
-
-        var nameofPolicy = p._policyName;
-        _moduleCache.Add(nameofPolicy, moduleToReturn);
-
-        p.Dispose();
+        return new Policy(opaPolicy, _serde);
     }
 }
diff --git a/spikes/HigherLevelApisSpike/Program.cs b/spikes/HigherLevelApisSpike/Program.cs
@@ -5,12 +5,11 @@
                     new NoOpModuleCache(),
                     new DefaultOpaSerializer());
 
-var policy = await factory.RentAsync("mysamplepolicy");
+var policy = await factory.GetAsync("mysamplepolicy");
 
 // if you want to be fancy use the string version on the root object
 // policy.Opa.SetData("");
 policy.SetData(new { blah = "blups" });
 
 policy.Evaluate(new { myName = "" });
 
-factory.Return(policy); // do not use policy after here, but return is optional re:IDisposable