buffet: Add command queue and command basic command dispatch mechanism
Added a skeleton CommandQueue class that would hold all the incoming
command instances from local and cloud GCD clients. For now, both
CommandQueue and CommandInstance are simple classes that encapsulate
the command instances received by buffet.
In following CLs, I'll add methods to parse command instance JSON
objects and provide D-Bus serlialization and dispatch to command
handlers (daemons).
BUG=chromium:396713
TEST=USE=buffet P2_TEST_FILTER="buffet::*" FEATURES=test emerge-link platform2
Change-Id: I7ab6bb0778a6320dc75d2a3c9b2a774ea5329054
Reviewed-on: https://chromium-review.googlesource.com/211412
Tested-by: Alex Vakulenko <avakulenko@chromium.org>
Reviewed-by: Christopher Wiley <wiley@chromium.org>
Commit-Queue: Alex Vakulenko <avakulenko@chromium.org>
diff --git a/buffet/commands/command_queue.h b/buffet/commands/command_queue.h
new file mode 100644
index 0000000..5d650a0
--- /dev/null
+++ b/buffet/commands/command_queue.h
@@ -0,0 +1,54 @@
+// 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_
