Wrap Output in a coroutine that periodically yields.

src/ripple/rpc/impl/Coroutine.cpp

@@ -0,0 +1,59 @@
+//------------------------------------------------------------------------------
+/*
+    This file is part of rippled: https://github.com/ripple/rippled
+    Copyright (c) 2012, 2013 Ripple Labs Inc.
+
+    Permission to use, copy, modify, and/or distribute this software for any
+    purpose  with  or without fee is hereby granted, provided that the above
+    copyright notice and this permission notice appear in all copies.
+
+    THE  SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+    WITH  REGARD  TO  THIS  SOFTWARE  INCLUDING  ALL  IMPLIED  WARRANTIES  OF
+    MERCHANTABILITY  AND  FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+    ANY  SPECIAL ,  DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+    WHATSOEVER  RESULTING  FROM  LOSS  OF USE, DATA OR PROFITS, WHETHER IN AN
+    ACTION  OF  CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+//==============================================================================
+
+#include <ripple/rpc/Coroutine.h>
+#include <ripple/rpc/impl/TestOutputSuite.h>
+
+namespace ripple {
+namespace RPC {
+
+using CoroutinePull = boost::coroutines::coroutine <void>::pull_type;
+
+struct Coroutine::Impl : CoroutinePull
+{
+    Impl (CoroutinePull&& p) : CoroutinePull (std::move(p)) {}
+};
+
+Coroutine::Coroutine (YieldFunction const& yieldFunction)
+{
+    CoroutinePull pull ([yieldFunction] (
+        boost::coroutines::coroutine <void>::push_type& push)
+    {
+        Yield yield = [&push] () { push(); };
+        yield ();
+        yieldFunction (yield);
+    });
+
+    impl_ = std::make_shared<Impl> (std::move (pull));
+}
+
+Coroutine::~Coroutine() = default;
+
+Coroutine::operator bool() const
+{
+    return bool (*impl_);
+}
+
+void Coroutine::operator()() const
+{
+    (*impl_)();
+}
+
+} // RPC
+} // ripple