Merge pull request #3 from deavmi/feature/cancellable_future

Cancellable future's

source/doap/client/client.d

@@ -111,8 +111,13 @@ public class CoapClient
         // Shutdown the messaging layer
         this.messaging.close();
         
-        // TODO: We must wake up other sleeprs with an error
-        // (somehow, pass it in, flag set)
+        // Cancel all active request futures
+        this.requestsLock.lock();
+        foreach(CoapRequest curReq; outgoingRequests)
+        {
+            curReq.future.cancel();
+        }
+        this.requestsLock.unlock();
     }
 
     /** 

source/doap/client/package.d

@@ -1,4 +1,4 @@
 module doap.client;
 
 public import doap.client.client : CoapClient;
-public import doap.client.request : CoapRequestBuilder, CoapRequestFuture;
+public import doap.client.request : CoapRequestBuilder, CoapRequestFuture, RequestState;

source/doap/client/request.d

@@ -257,6 +257,29 @@ package class CoapRequestBuilder
 import core.sync.mutex : Mutex;
 import core.sync.condition : Condition;
 
+
+/** 
+ * The state of a `CoapRequestFuture`
+ */
+public enum RequestState
+{
+    /** 
+     * The future has been created
+     */
+    CREATED,
+
+    /** 
+     * The future has completed
+     * successfully
+     */
+    COMPLETED,
+
+    /** 
+     * The future was cancelled
+     */
+    CANCELLED
+}
+
 /** 
  * This is returned to the user when he
  * does a finalizing call on a `CoapRequestBuilder`
@@ -277,7 +300,12 @@ public class CoapRequestFuture
      * This is filled in by the
      * messaging layer.
      */
-    private CoapPacket response;
+    private CoapPacket response; // TODO: Volatility?
+
+    /** 
+     * State of the future
+     */
+    private RequestState state; // TODO: Volatility?
 
     /** 
      * Mutex (for the condition to use)
@@ -298,6 +326,7 @@ public class CoapRequestFuture
      */
     package this()
     {
+        this.state = RequestState.CREATED;
         this.mutex = new Mutex();
         this.condition = new Condition(mutex);
     }
@@ -316,6 +345,23 @@ public class CoapRequestFuture
         // Set the received response
         this.response = response;
 
+        // Set completion state
+        this.state = RequestState.COMPLETED;
+
+        // Wake up the sleepers
+        this.condition.notifyAll();
+    }
+
+    /** 
+     * Cancels this future such that
+     * all calls to `get()` will
+     * unblock and throw an exception
+     */
+    package void cancel()
+    {
+        // Set cancelled state
+        this.state = RequestState.CANCELLED;
+
         // Wake up the sleepers
         this.condition.notifyAll();
     }
@@ -324,6 +370,8 @@ public class CoapRequestFuture
      * Blocks until the response is received
      *
      * Returns: the response as a `CoapPacket`
+     * Throws:
+     *     CoapException on cancelled request
      */
     public CoapPacket get()
     {
@@ -337,7 +385,25 @@ public class CoapRequestFuture
         // Upon waking up release lock
         this.mutex.unlock();
 
-        return this.response;
+        // If successfully completed
+        if(this.state == RequestState.COMPLETED)
+        {
+            return this.response;
+        }
+        // On error
+        else
+        {
+            throw new CoapException("Request future cancelled");
+        }   
     }
 
+    /** 
+     * Returns the state of this future
+     *
+     * Returns: the state
+     */
+    public RequestState getState()
+    {
+        return this.state;
+    }
 }