handleFinish

runtime/src/main/java/org/capnproto/RpcState.java

@@ -445,6 +445,30 @@ final class RpcState {
     }
 
     void handleFinish(RpcProtocol.Finish.Reader finish) {
+        List<Integer> exportsToRelease = null;
+        var answer = answers.find(finish.getQuestionId());
+        if (answer == null || !answer.active) {
+            assert false: "'Finish' for invalid question ID.";
+            return;
+        }
+
+        if (finish.getReleaseResultCaps()) {
+            exportsToRelease = answer.resultExports;
+        }
+        answer.resultExports = null;
+
+        var pipelineToRelease = answer.pipeline;
+        answer.pipeline = null;
+
+        // If the call isn't actually done yet, cancel it.  Otherwise, we can go ahead and erase the
+        // question from the table.
+        var ctx = answer.callContext;
+        if (ctx != null) {
+            ctx.requestCancel();
+        }
+        else {
+            answers.erase(finish.getQuestionId());
+        }
     }
 
     void handleResolve(IncomingRpcMessage message, RpcProtocol.Resolve.Reader resolve) {
@@ -1003,15 +1027,15 @@ final class RpcState {
         }
 
         RpcResponse consumeRedirectedResponse() {
-                assert this.redirectResults;
+            assert this.redirectResults;
 
-                if (this.response == null) {
-                    getResults(); // force initialization of response
-                }
-
-                return ((LocallyRedirectedRpcResponse)this.response);
+            if (this.response == null) {
+                getResults(); // force initialization of response
             }
 
+            return ((LocallyRedirectedRpcResponse) this.response);
+        }
+
         void sendReturn() {
             assert !redirectResults;
 
@@ -1029,7 +1053,7 @@ final class RpcState {
 
             List<Integer> exports;
             try {
-                exports = ((RpcServerResponseImpl)response).send();
+                exports = ((RpcServerResponseImpl) response).send();
             }
             catch (Throwable exc) {
                 this.responseSent = false;
@@ -1081,6 +1105,24 @@ final class RpcState {
                 }
             }
         }
+
+        public void requestCancel() {
+            // Hints that the caller wishes to cancel this call.  At the next time when cancellation is
+            // deemed safe, the RpcCallContext shall send a canceled Return -- or if it never becomes
+            // safe, the RpcCallContext will send a normal return when the call completes.  Either way
+            // the RpcCallContext is now responsible for cleaning up the entry in the answer table, since
+            // a Finish message was already received.
+
+            boolean previouslyAllowedButNotRequested = (this.cancelAllowed && !this.cancelRequested);
+            this.cancelRequested = true;
+
+            if (previouslyAllowedButNotRequested) {
+                // We just set CANCEL_REQUESTED, and CANCEL_ALLOWED was already set previously.  Initiate
+                // the cancellation.
+                this.cancelled.complete(null);
+            }
+            // TODO do we care about cancelRequested if further completions are effectively ignored?
+        }
     }
 
     enum PipelineState {