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/* Copyright © 2003-2013 Roger Leigh <rleigh@debian.org>
*
* schroot is free software: you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* schroot is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see
* <http://www.gnu.org/licenses/>.
*
*********************************************************************/
#ifndef SBUILD_MNTSTREAM_H
#define SBUILD_MNTSTREAM_H
#include <sbuild/custom-error.h>
#include <iostream>
#include <deque>
#include <string>
#include <stdio.h>
#include <sys/types.h>
#include <mntent.h>
namespace sbuild
{
/**
* Access mounts. This is a wrapper around the setmntent(3),
* getmntent(3) and endmntent(3) functions, which are used to read a
* stream of "mntents" through multiple getmntent() calls.
*
* mntstream calls setmntent() and endmntent() automatically, and
* represents each mntent as a mntstream::mntentry. Like reading
* from and istream by pulling data out with the >> "extraction
* operator", mntentries are also extracted from the mntstream with
* the >> operator.
*/
class mntstream
{
public:
/// Error codes.
enum error_code
{
MNT_OPEN, ///< Failed to open mount file.
MNT_READ ///< Failed to read mount file.
};
/// Exception type.
typedef sbuild::custom_error<error_code> error;
/**
* An entry in a mntstream. It is a wrapper around the mntent
* structure declared in mntent.h. Unlike a mntent pointer returned
* by getmntent(3), a mntentry does not become invalid when the
* mntstream it was extracted from is destroyed.
*/
struct mntentry
{
/// The constructor.
mntentry ()
{};
/**
* The contructor.
*
* @param entry the mntent structure to wrap.
*/
mntentry (const struct mntent& entry);
/// Name of mounted filesystem.
std::string filesystem_name;
/// File system path prefix.
std::string directory;
/// Mount type.
std::string type;
/// Mount options.
std::string options;
/// Dump frequency (days).
int dump_frequency;
/// Parallel fsck pass number.
int fsck_pass;
};
/**
* The constructor.
*
* @param file the file to read.
*/
mntstream(const std::string& file);
/// The destructor.
virtual ~mntstream();
/**
* Open a mount file for reading. This uses the openmnt(3) call
* to open the underlying FILE stream. Any previously open
* mount file is closed before opening the new one. The
* mntstream error state is set if the open fails, and an
* exception will be thrown.
*
* @param file the file to read.
* @see close()
*/
void open(const std::string& file);
/**
* Close the mount file. This uses the closemnt(3) call to
* close the underlying FILE stream. All cached data is deleted
* and the error state set until open() is called.
*
* @see open()
*/
void close();
/**
* Check for End Of File. Note that the end of file status is
* only set adter a read fails, so this should be checked after
* each read.
*
* @returns true if the mntstream is empty, otherwise false.
*/
bool eof() const;
/**
* Check for errors. If there is an error, the mntstream is
* unusable until the next open() call.
*
* @returns true if the mntstream is in an error state, otherwise
* false.
*/
bool bad() const;
/**
* Check if the mntstream status is good.
*
* @returns true if the status is good (eof() and bad() both
* return false).
*/
operator bool ();
/**
* Check if the mntstream status is bad.
*
* @returns true if the status is bad (eof() or bad() return
* true).
*/
bool
operator ! ();
friend mntstream&
operator >> (mntstream& stream,
mntentry& entry);
private:
/**
* Read mntents from the underlying FILE stream into the data
* deque. If the read fails, the error state will be set, and
* an exception will be thrown.
*
* @param quantity the number of mntents to read.
*
* @todo Add mntentry constructor to do automatic struct mntent
* to mntentry conversion.
*/
void read (int quantity=1);
/// The file name.
std::string file;
/// The underlying FILE stream.
FILE *mntfile;
/**
* A list of mntentries represents the mount file stream as a
* LIFO stack.
*/
std::deque<mntentry> data;
/// Error status.
bool error_status;
/// End of File status.
bool eof_status;
};
/**
* The overloaded extraction operator. This is used to pull
* mntentries from a mntstream.
*
* @param stream the mntstream to get input from.
* @param entry the mntentry to set.
* @returns the mntstream.
*/
mntstream&
operator >> (mntstream& stream,
mntstream::mntentry& entry);
}
#endif /* SBUILD_MNTSTREAM_H */
/*
* Local Variables:
* mode:C++
* End:
*/
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