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// Copyright (C) 2012-2024 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 MASTER_LOADER_H
#define MASTER_LOADER_H
#include <dns/exceptions.h>
#include <dns/master_loader_callbacks.h>
#include <boost/noncopyable.hpp>
#include <memory>
namespace isc {
namespace dns {
class Name;
class RRClass;
/// \brief Error while loading by MasterLoader without specifying the
/// MANY_ERRORS option.
class MasterLoaderError : public isc::Exception {
public:
MasterLoaderError(const char* file, size_t line, const char* what) :
Exception(file, line, what)
{}
};
/// \brief A class able to load DNS master files
///
/// This class is able to produce a stream of RRs from a master file.
/// It is able to load all of the master file at once, or by blocks
/// incrementally.
///
/// It reports the loaded RRs and encountered errors by callbacks.
class MasterLoader : boost::noncopyable {
public:
/// \brief Options how the parsing should work.
enum Options {
DEFAULT = 0, ///< Nothing special.
MANY_ERRORS = 1 ///< Lenient mode (see documentation of MasterLoader
/// constructor).
};
/// \brief Constructor
///
/// This creates a master loader and provides it with all
/// relevant information.
///
/// Except for the exceptions listed below, the constructor doesn't
/// throw. Most errors (like non-existent master file) are reported
/// by the callbacks during load() or loadIncremental().
///
/// \param master_file Path to the file to load.
/// \param zone_origin The origin of zone to be expected inside
/// the master file. Currently unused, but it is expected to
/// be used for some validation.
/// \param zone_class The class of zone to be expected inside the
/// master file.
/// \param callbacks The callbacks by which it should report problems.
/// Usually, the callback carries a filename and line number of the
/// input where the problem happens. There's a special case of empty
/// filename and zero line in case the opening of the top-level master
/// file fails.
/// \param add_callback The callback which would be called with each
/// loaded RR.
/// \param options Options for the parsing, which is bitwise-or of
/// the Options values or DEFAULT. If the MANY_ERRORS option is
/// included, the parser tries to continue past errors. If it
/// is not included, it stops at first encountered error.
/// \throw std::bad_alloc when there's not enough memory.
/// \throw isc::InvalidParameter if add_callback is empty.
MasterLoader(const char* master_file,
const Name& zone_origin,
const RRClass& zone_class,
const MasterLoaderCallbacks& callbacks,
const AddRRCallback& add_callback,
Options options = DEFAULT);
/// \brief Constructor from a stream
///
/// This is a constructor very similar to the previous one. The only
/// difference is it doesn't take a filename, but an input stream
/// to read the data from. It is expected to be mostly used in tests,
/// but it is public as it may possibly be useful for other currently
/// unknown purposes.
MasterLoader(std::istream& input,
const Name& zone_origin,
const RRClass& zone_class,
const MasterLoaderCallbacks& callbacks,
const AddRRCallback& add_callback,
Options options = DEFAULT);
/// \brief Destructor
~MasterLoader();
/// \brief Load some RRs
///
/// This method loads at most count_limit RRs and reports them. In case
/// an error (either fatal or without MANY_ERRORS) or end of file is
/// encountered, they may be less.
///
/// \param count_limit Upper limit on the number of RRs loaded.
/// \return In case it stops because of the count limit, it returns false.
/// It returns true if the loading is done.
/// \throw isc::InvalidOperation when called after loading was done
/// already.
/// \throw MasterLoaderError when there's an error in the input master
/// file and the MANY_ERRORS is not specified. It never throws this
/// in case MANY_ERRORS is specified.
bool loadIncremental(size_t count_limit);
/// \brief Load everything
///
/// This simply calls loadIncremental until the loading is done.
/// \throw isc::InvalidOperation when called after loading was done
/// already.
/// \throw MasterLoaderError when there's an error in the input master
/// file and the MANY_ERRORS is not specified. It never throws this
/// in case MANY_ERRORS is specified.
void load() {
while (!loadIncremental(1000)) { // 1000 = arbitrary largish number
// Body intentionally left blank
}
}
/// \brief Was the loading successful?
///
/// \return true if and only if the loading was complete (after a call of
/// load or after loadIncremental returned true) and there was no
/// error. In other cases, return false.
/// \note While this method works even before the loading is complete (by
/// returning false in that case), it is meant to be called only after
/// finishing the load.
bool loadedSuccessfully() const;
/// \brief Return the total size of the zone files and streams.
///
/// This method returns the size of the source of the zone to be loaded
/// (master zone files or streams) that is known at the time of the call.
/// For a zone file, it's the size of the file; for a stream, it's the
/// size of the data (in bytes) available at the start of the load.
/// If separate zone files are included via the $INCLUDE directive, the
/// sum of the sizes of these files are added.
///
/// If the loader is constructed with a stream, the size can be
/// "unknown" as described for \c MasterLexer::getTotalSourceSize().
/// In this case this method always returns
/// \c MasterLexer::SOURCE_SIZE_UNKNOWN.
///
/// If the loader is constructed with a zone file, this method
/// initially returns 0. So until either \c load() or \c loadIncremental()
/// is called, the value is meaningless.
///
/// Note that when the source includes separate files, this method
/// cannot take into account the included files that the loader has not
/// recognized at the time of call. So it's possible that this method
/// returns different values at different times of call.
///
/// \throw None
size_t getSize() const;
/// \brief Return the position of the loader in zone.
///
/// This method returns a conceptual "position" of the loader in the
/// zone to be loaded. Specifically, it returns the total number of
/// characters contained in the zone files and streams and recognized
/// by the loader. Before starting the load it returns 0; on successful
/// completion it will be equal to the return value of \c getSize()
/// (unless the latter returns \c MasterLexer::SOURCE_SIZE_UNKNOWN).
///
/// \throw None
size_t getPosition() const;
private:
class MasterLoaderImpl;
std::unique_ptr<MasterLoaderImpl> impl_;
};
} // end namespace dns
} // end namespace isc
#endif // MASTER_LOADER_H
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