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// Copyright 2014 The Chromium OS Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef BUFFET_COMMANDS_COMMAND_QUEUE_H_
#define BUFFET_COMMANDS_COMMAND_QUEUE_H_
#include <map>
#include <memory>
#include <string>
#include <base/basictypes.h>
#include "buffet/commands/command_instance.h"
namespace buffet {
class CommandQueue final {
public:
CommandQueue() = default;
// Checks if the command queue is empty.
bool IsEmpty() const { return map_.empty(); }
// Returns the number of commands in the queue.
size_t GetCount() const { return map_.size(); }
// Adds a new command to the queue. Each command in the queue has a unique
// ID that identifies that command instance. The ID string of the added
// command is returned by this method.
std::string Add(std::unique_ptr<const CommandInstance> instance);
// Removes a command identified by |id| from the queue. Returns a unique
// pointer to the command instance if removed successfully, or an empty
// unique_ptr if the command with the given ID doesn't exist in the queue.
std::unique_ptr<const CommandInstance> Remove(const std::string& id);
// Finds a command instance in the queue by the instance |id|. Returns
// nullptr if the command with the given |id| is not found. The returned
// pointer should not be persisted for a long period of time.
const CommandInstance* Find(const std::string& id) const;
private:
// ID-to-CommandInstance map.
std::map<std::string, std::unique_ptr<const CommandInstance>> map_;
// Counter for generating unique command IDs.
int next_id_ = 0;
DISALLOW_COPY_AND_ASSIGN(CommandQueue);
};
} // namespace buffet
#endif // BUFFET_COMMANDS_COMMAND_QUEUE_H_