crimson/common: a new condition variable

Signed-off-by: Xuehan Xu <xxhdx1985126@gmail.com>

diff --git a/src/crimson/common/condition_variable.h b/src/crimson/common/condition_variable.h
new file mode 100644 (file)
index 0000000..19267f3
--- /dev/null
+++ b/src/crimson/common/condition_variable.h
@@ -0,0 +1,43 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:nil -*-
+// vim: ts=8 sw=2 smarttab
+
+#pragma once
+
+#include <seastar/core/future.hh>
+#include <seastar/core/condition-variable.hh>
+#include <seastar/core/loop.hh>
+
+#include "crimson/common/interruptible_future.h"
+
+namespace crimson {
+
+class condition_variable : public seastar::condition_variable {
+public:
+  template <typename Pred, typename Func>
+  auto wait(
+    Pred&& pred,
+    Func&& action) noexcept {
+    using func_result_t = std::invoke_result_t<Func>;
+    using intr_errorator_t = typename func_result_t::interrupt_errorator_type;
+    using intr_cond_t = typename func_result_t::interrupt_cond_type;
+    using interruptor = crimson::interruptible::interruptor<intr_cond_t>;
+    return interruptor::repeat(
+      [this, pred=std::forward<Pred>(pred),
+      action=std::forward<Func>(action)]()
+      -> typename intr_errorator_t::template future<seastar::stop_iteration> {
+      if (!pred()) {
+       return seastar::condition_variable::wait().then([] {
+         return seastar::make_ready_future<
+           seastar::stop_iteration>(seastar::stop_iteration::no);
+       });
+      } else {
+       return action().si_then([] {
+         return seastar::make_ready_future<
+           seastar::stop_iteration>(seastar::stop_iteration::yes);
+       });
+      }
+    });
+  }
+};
+
+} // namespace crimson