blob: f76862a38a4bfd7bdd07a20a370c6ad313a80ac4 [file] [log] [blame]
// Copyright 2018 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include <functional>
#include <memory>
#include <lib/fit/function.h>
#include <lib/fxl/compiler_specific.h>
#include <lib/fxl/memory/ref_ptr.h>
#include "peridot/bin/ledger/fidl/include/types.h"
namespace ledger {
// Helper class for waiting for asynchronous event.
// For a given |CallbackWaiter|, one can retrieve a callback through
// |GetCallback|. The callback must be called when the asynchronous event
// ends.
// When |RunUntilCalled| is called, it will run the event loop, until either the
// callback from |GetCallback| is called or or the loop determines that the
// callback will never be called. It returns |true|, if the callback has been
// called, |false| otherwise. If one is waiting for the callback to be called
// multiple times, one can execute |RunUntilCalled| multiple times. The |n|th
// run of |RunUntilCalled| will return once the callback have been called at
// least |n| time. |GetCallback| can be called multiple time, and all the
// returned callback will be equivalent.
class CallbackWaiter {
CallbackWaiter() {}
virtual ~CallbackWaiter() {}
virtual fit::function<void()> GetCallback() = 0;
virtual bool RunUntilCalled() FXL_WARN_UNUSED_RESULT = 0;
// Returns whether the next expected calback has not already been called. If
// |false|, |RunUntilCalled| will return immediately.
virtual bool NotCalledYet() = 0;
// A subloop.
class SubLoop {
virtual ~SubLoop() {}
// Runs all currently enqueued tasks on the loop and quits the loop. The
// SubLoop must not be used again once this method returns.
virtual void DrainAndQuit() = 0;
// Returns a dispatcher whose runloop is owned by |this|.
virtual async_dispatcher_t* dispatcher() = 0;
// Controller for the main run loop. This allows to control the loop that will
// call the factory and the multiple instances.
class LoopController {
virtual ~LoopController(){};
// Runs the loop.
virtual void RunLoop() = 0;
// Stops the loop.
virtual void StopLoop() = 0;
// Starts a new subloop.
virtual std::unique_ptr<SubLoop> StartNewLoop() = 0;
// Returns a waiter that can be used to run the loop until a callback has
// been called.
virtual std::unique_ptr<CallbackWaiter> NewWaiter() = 0;
// Returns the dispatcher.
virtual async_dispatcher_t* dispatcher() = 0;
// Runs the loop until |condition| returns true.
virtual bool RunLoopUntil(fit::function<bool()> condition) = 0;
// Runs the loop until |duration| as passed.
virtual void RunLoopFor(zx::duration duration) = 0;
} // namespace ledger