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// Copyright (c) 2011 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 UPDATE_ENGINE_ACTION_PROCESSOR_H_
#define UPDATE_ENGINE_ACTION_PROCESSOR_H_
#include <deque>
#include "base/basictypes.h"
#include "update_engine/error_code.h"
// The structure of these classes (Action, ActionPipe, ActionProcessor, etc.)
// is based on the KSAction* classes from the Google Update Engine code at
// http://code.google.com/p/update-engine/ . The author of this file sends
// a big thanks to that team for their high quality design, implementation,
// and documentation.
// See action.h for an overview of this class and other other Action* classes.
// An ActionProcessor keeps a queue of Actions and processes them in order.
namespace chromeos_update_engine {
class AbstractAction;
class ActionProcessorDelegate;
class ActionProcessor {
public:
ActionProcessor();
virtual ~ActionProcessor();
// Starts processing the first Action in the queue. If there's a delegate,
// when all processing is complete, ProcessingDone() will be called on the
// delegate.
virtual void StartProcessing();
// Aborts processing. If an Action is running, it will have
// TerminateProcessing() called on it. The Action that was running
// will be lost and must be re-enqueued if this Processor is to use it.
void StopProcessing();
// Returns true iff an Action is currently processing.
bool IsRunning() const { return NULL != current_action_; }
// Adds another Action to the end of the queue.
virtual void EnqueueAction(AbstractAction* action);
// Sets/gets the current delegate. Set to NULL to remove a delegate.
ActionProcessorDelegate* delegate() const { return delegate_; }
void set_delegate(ActionProcessorDelegate *delegate) {
delegate_ = delegate;
}
// Returns a pointer to the current Action that's processing.
AbstractAction* current_action() const {
return current_action_;
}
// Called by an action to notify processor that it's done. Caller passes self.
void ActionComplete(AbstractAction* actionptr, ErrorCode code);
private:
// Actions that have not yet begun processing, in the order in which
// they'll be processed.
std::deque<AbstractAction*> actions_;
// A pointer to the currrently processing Action, if any.
AbstractAction* current_action_;
// A pointer to the delegate, or NULL if none.
ActionProcessorDelegate *delegate_;
DISALLOW_COPY_AND_ASSIGN(ActionProcessor);
};
// A delegate object can be used to be notified of events that happen
// in an ActionProcessor. An instance of this class can be passed to an
// ActionProcessor to register itself.
class ActionProcessorDelegate {
public:
// Called when all processing in an ActionProcessor has completed. A pointer
// to the ActionProcessor is passed. |code| is set to the exit code of the
// last completed action.
virtual void ProcessingDone(const ActionProcessor* processor,
ErrorCode code) {}
// Called when processing has stopped. Does not mean that all Actions have
// completed. If/when all Actions complete, ProcessingDone() will be called.
virtual void ProcessingStopped(const ActionProcessor* processor) {}
// Called whenever an action has finished processing, either successfully
// or otherwise.
virtual void ActionCompleted(ActionProcessor* processor,
AbstractAction* action,
ErrorCode code) {}
};
} // namespace chromeos_update_engine
#endif // UPDATE_ENGINE_ACTION_PROCESSOR_H_
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