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// Copyright (C) 2017 Internet Systems Consortium, Inc. ("ISC")
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.
#ifndef HOOKED_COMMAND_MGR_H
#define HOOKED_COMMAND_MGR_H
#include <cc/data.h>
#include <config/base_command_mgr.h>
namespace isc {
namespace config {
/// @brief Command Manager which can delegate commands to a hook library.
///
/// This class extends @ref BaseCommandMgr with the logic to delegate the
/// commands to a hook library if the hook library is installed and provides
/// command handlers for the control API.
///
/// The command handlers are registered by a hook library by calling
/// @ref isc::hooks::LibraryHandle::registerCommandCallout. This call
/// creates a hook point for this command (if one doesn't exist) and then
/// registers the specified handler(s). When the @ref HookedCommandMgr
/// receives a command for processing it calls the
/// @ref isc::hooks::HooksManager::commandHandlersPresent to check if there
/// are handlers present for this command. If so, the @ref HookedCommandMgr
/// calls @ref isc::hooks::HooksManager::callCommandHandlers to process
/// the command in the hooks libraries. If command handlers are not installed
/// for this command, the @ref HookedCommandMgr will try to process the
/// command on its own.
///
/// The @ref isc::hooks::CalloutHandle::CalloutNextStep flag setting by the
/// command handlers does NOT have any influence on the operation of the
/// @ref HookedCommandMgr, i.e. it will always skip processing command on
/// its own if the command handlers are present for the given command, even
/// if the handlers return an error code.
class HookedCommandMgr : public BaseCommandMgr {
public:
/// @brief Constructor.
///
/// Initializes callout handle used by the Command Manager.
HookedCommandMgr();
protected:
/// @brief Handles the command within the hooks libraries.
///
/// This method checks if the hooks libraries are installed which implement
/// command handlers for the specified command to be processed. If the
/// command handlers are present, this method calls them to create a response
/// and then passes the response back within the @c answer argument.
///
/// Values of all arguments can be modified by the hook library.
///
/// @param cmd_name Command name.
/// @param params Command arguments.
/// @param original_cmd Original command received.
/// @param [out] answer Command processing result returned by the hook.
///
/// @return Boolean value indicating if any callouts have been executed.
bool
delegateCommandToHookLibrary(const std::string& cmd_name,
const isc::data::ConstElementPtr& params,
const isc::data::ConstElementPtr& original_cmd,
isc::data::ElementPtr& answer);
/// @brief Handles the command having a given name and arguments.
///
/// This method calls @ref HookedCommandMgr::delegateCommandToHookLibrary to
/// try to process the command with the hook libraries, if they are installed.
///
/// @param cmd_name Command name.
/// @param params Command arguments.
/// @param original_cmd Original command received.
///
/// @return Pointer to the const data element representing response
/// to a command.
virtual isc::data::ConstElementPtr
handleCommand(const std::string& cmd_name,
const isc::data::ConstElementPtr& params,
const isc::data::ConstElementPtr& original_cmd);
};
} // end of namespace isc::config
} // end of namespace isc
#endif
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