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// 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 <fuchsia/modular/storymodel/cpp/fidl.h>
#include <lib/fit/bridge.h>
#include <lib/fxl/macros.h>
namespace modular {
// Implemented by and created by the StoryModelOwner.
// An instance of StoryMutator is provided to all clients that wish to perform
// mutations on a StoryModel. It is responsible for consuming mutation commands
// (exposed as methods publicly and converted to StoryModelMutation internally)
// and dispatching them be applied to a shared StoryModel instance.
// This is an interface in order to aid in testing clients that depend on
// StoryMutator.
class StoryMutator {
virtual ~StoryMutator();
// The following mutators issue a single mutation instruction to
// change the StoryModel.
// The returned fit::consumer<> will eventually be completed with the result
// of the mutation operation, HOWEVER success does not guarantee that
// observers of the StoryModel will see those same changes reflected, and thus
// clients should NOT perform side-effects under that assumption.
// It IS safe to perform side-effects once mutations have been observed
// through StoryObserver.
// A failure guarantees that the mutation was not applied and it is safe to
// retry.
// Sets the value of |StoryModel.runtime_state|.
fit::consumer<> set_runtime_state(
fuchsia::modular::StoryState state);
// Sets the value of |StoryModel.visibility_state|.
fit::consumer<> set_visibility_state(
fuchsia::modular::StoryVisibilityState state);
// Executes |commands| in order and in a single transaction.
virtual fit::consumer<> ExecuteInternal(
commands) = 0;
} // namespace modular