Split out cache

PureGym/Api.fs

@@ -5,86 +5,6 @@ open System.Net.Http
 open System.Threading
 open System.Threading.Tasks
 
-type private CacheMessage<'a> =
-    | TriggerUpdate
-    | UpdateStored of 'a Task
-    | Get of AsyncReplyChannel<'a>
-    | Quit of AsyncReplyChannel<unit>
-
-type Cache<'a> (obtainNew : CancellationToken -> 'a Task, expiry : 'a -> DateTime option) =
-    let cts = new CancellationTokenSource ()
-
-    let initialValue = obtainNew cts.Token
-
-    let rec handle (value : 'a Task) (mailbox : MailboxProcessor<CacheMessage<'a>>) : Async<unit> =
-        async {
-            let! message = mailbox.Receive ()
-
-            match message with
-            | Quit channel ->
-                channel.Reply ()
-                return ()
-            | CacheMessage.UpdateStored newValue -> return! handle newValue mailbox
-            | CacheMessage.TriggerUpdate ->
-                async {
-                    let! a = Async.AwaitTask (obtainNew cts.Token)
-                    let expiry = expiry a
-
-                    match expiry with
-                    | None -> return ()
-                    | Some expiry ->
-
-                    // a bit sloppy but :shrug:
-                    do! Async.Sleep ((expiry - DateTime.Now) - TimeSpan.FromMinutes 1.0)
-
-                    try
-                        mailbox.Post CacheMessage.TriggerUpdate
-                    with _ ->
-                        // Post during shutdown sequence: drop it on the floor
-                        ()
-
-                    return ()
-                }
-                |> fun a -> Async.Start (a, cancellationToken = cts.Token)
-
-                return! handle value mailbox
-            | CacheMessage.Get reply ->
-                let! valueAwaited = Async.AwaitTask value
-                reply.Reply valueAwaited
-                return! handle value mailbox
-        }
-
-    let mailbox = new MailboxProcessor<_> (handle initialValue)
-
-    do
-        mailbox.Start ()
-        mailbox.Post CacheMessage.TriggerUpdate
-
-    let isDisposing = ref 0
-    let hasDisposed = TaskCompletionSource<unit> ()
-
-    member this.GetCurrentValue () =
-        try
-            mailbox.PostAndAsyncReply CacheMessage.Get
-        with
-        // TODO I think this is the right exception...
-        | :? InvalidOperationException ->
-            raise (ObjectDisposedException (nameof (Cache)))
-
-    interface IDisposable with
-        member _.Dispose () =
-            if Interlocked.Increment isDisposing = 1 then
-                mailbox.PostAndReply CacheMessage.Quit
-                (mailbox :> IDisposable).Dispose ()
-                // We can't terminate the CTS until the mailbox has processed all client requests.
-                // Otherwise we terminate the mailbox's state Task before it has finished querying that
-                // task on behalf of clients.
-                cts.Cancel ()
-                cts.Dispose ()
-                hasDisposed.SetResult ()
-            else
-                hasDisposed.Task.Result
-
 /// Methods for interacting with the PureGym REST API.
 [<RequireQualifiedAccess>]
 module Api =

PureGym/Cache.fs

@@ -0,0 +1,86 @@
+namespace PureGym
+
+open System
+open System.Threading
+open System.Threading.Tasks
+
+type private CacheMessage<'a> =
+    | TriggerUpdate
+    | UpdateStored of 'a Task
+    | Get of AsyncReplyChannel<'a>
+    | Quit of AsyncReplyChannel<unit>
+
+type internal Cache<'a> (obtainNew : CancellationToken -> 'a Task, expiry : 'a -> DateTime option) =
+    let cts = new CancellationTokenSource ()
+
+    let initialValue = obtainNew cts.Token
+
+    let rec handle (value : 'a Task) (mailbox : MailboxProcessor<CacheMessage<'a>>) : Async<unit> =
+        async {
+            let! message = mailbox.Receive ()
+
+            match message with
+            | Quit channel ->
+                channel.Reply ()
+                return ()
+            | CacheMessage.UpdateStored newValue -> return! handle newValue mailbox
+            | CacheMessage.TriggerUpdate ->
+                async {
+                    let! a = Async.AwaitTask (obtainNew cts.Token)
+                    let expiry = expiry a
+
+                    match expiry with
+                    | None -> return ()
+                    | Some expiry ->
+
+                    // a bit sloppy but :shrug:
+                    do! Async.Sleep ((expiry - DateTime.Now) - TimeSpan.FromMinutes 1.0)
+
+                    try
+                        mailbox.Post CacheMessage.TriggerUpdate
+                    with _ ->
+                        // Post during shutdown sequence: drop it on the floor
+                        ()
+
+                    return ()
+                }
+                |> fun a -> Async.Start (a, cancellationToken = cts.Token)
+
+                return! handle value mailbox
+            | CacheMessage.Get reply ->
+                let! valueAwaited = Async.AwaitTask value
+                reply.Reply valueAwaited
+                return! handle value mailbox
+        }
+
+    let mailbox = new MailboxProcessor<_> (handle initialValue)
+
+    do
+        mailbox.Start ()
+        mailbox.Post CacheMessage.TriggerUpdate
+
+    let isDisposing = ref 0
+    let hasDisposed = TaskCompletionSource<unit> ()
+
+    member this.GetCurrentValue () =
+        try
+            mailbox.PostAndAsyncReply CacheMessage.Get
+        with
+        // TODO I think this is the right exception...
+        | :? InvalidOperationException ->
+            raise (ObjectDisposedException (nameof (Cache)))
+
+    interface IDisposable with
+        member _.Dispose () =
+            if Interlocked.Increment isDisposing = 1 then
+                mailbox.PostAndReply CacheMessage.Quit
+                (mailbox :> IDisposable).Dispose ()
+                // We can't terminate the CTS until the mailbox has processed all client requests.
+                // Otherwise we terminate the mailbox's state Task before it has finished querying that
+                // task on behalf of clients.
+                cts.Cancel ()
+                cts.Dispose ()
+                hasDisposed.SetResult ()
+            else
+                hasDisposed.Task.Result
+

PureGym/PureGym.fsproj

@@ -20,6 +20,7 @@
       <Compile Include="GeneratedClient.fs">
         <MyriadFile>Client.fs</MyriadFile>
       </Compile>
+      <Compile Include="Cache.fs" />
       <Compile Include="Api.fs" />
       <Compile Include="GymSelector.fs" />
       <EmbeddedResource Include="SurfaceBaseline.txt" />

PureGym/SurfaceBaseline.txt

@@ -38,9 +38,6 @@ PureGym.AuthToken.get_ExpiryTime [method]: unit -> System.DateTime option
 PureGym.AuthTokenModule inherit obj
 PureGym.AuthTokenModule.get [static method]: PureGym.UsernamePin -> System.Threading.CancellationToken -> PureGym.AuthToken System.Threading.Tasks.Task
 PureGym.AuthTokenModule.ofBearerToken [static method]: string -> PureGym.AuthToken
-PureGym.Cache`1 inherit obj, implements IDisposable
-PureGym.Cache`1..ctor [constructor]: (System.Threading.CancellationToken -> 'a System.Threading.Tasks.Task, 'a -> System.DateTime option)
-PureGym.Cache`1.GetCurrentValue [method]: unit -> 'a Microsoft.FSharp.Control.FSharpAsync
 PureGym.Gym inherit obj, implements PureGym.Gym System.IEquatable, System.Collections.IStructuralEquatable, PureGym.Gym System.IComparable, System.IComparable, System.Collections.IStructuralComparable
 PureGym.Gym..ctor [constructor]: (string, int, int, PureGym.GymAddress, string, string, PureGym.GymOpeningHours, PureGym.GymAccessOptions, PureGym.GymLocation, string, string)
 PureGym.Gym.AccessOptions [property]: [read-only] PureGym.GymAccessOptions