/*
    This file is part of the KDE libraries
    SPDX-FileCopyrightText: 2003 Waldo Bastian <bastian@kde.org>
    SPDX-FileCopyrightText: 2007 David Faure <faure@kde.org>

    SPDX-License-Identifier: LGPL-2.0-only
*/

#ifndef KMOUNTPOINT_H
#define KMOUNTPOINT_H

#include "kiocore_export.h"

#include <QExplicitlySharedDataPointer>
#include <QStringList>

#include <memory>
#include <sys/types.h> // dev_t among other definitions

class KMountPointPrivate;

/**
 * @class KMountPoint kmountpoint.h <KMountPoint>
 *
 * The KMountPoint class provides information about mounted and unmounted disks.
 * It provides a system independent interface to fstab.
 *
 * @author Waldo Bastian <bastian@kde.org>
 */
class KIOCORE_EXPORT KMountPoint : public QSharedData
{
public:
    using Ptr = QExplicitlySharedDataPointer<KMountPoint>;

    /**
     * List of mount points.
     */
    class KIOCORE_EXPORT List : public QList<Ptr>
    {
    public:
        List();
        /**
         * Find the mountpoint on which resides @p path
         * For instance if /home is a separate partition, findByPath("/home/user/blah")
         * will return /home
         * @param path the path to check
         * @return the mount point of the given file
         */
        Ptr findByPath(const QString &path) const;

        /**
         * Returns the mount point associated with @p device,
         * i.e. the one where mountedFrom() == @p device
         * (after symlink resolution).
         * @return the mountpoint, or @c nullptr if this device doesn't exist or isn't mounted
         */
        Ptr findByDevice(const QString &device) const;
    };

public:
    /**
     * Flags that specify which additional details should be fetched for each mountpoint.
     * @see DetailsNeededFlags
     */
    enum DetailsNeededFlag {
        /**
         * Only the basic details: mountedFrom, mountPoint, mountType.
         */
        BasicInfoNeeded = 0,
        /**
         * Also fetch the options used when mounting, see KMountPoint::mountOptions().
         */
        NeedMountOptions = 1,
        /**
         * Also fetch the device name (with symlinks resolved), see KMountPoint::realDeviceName().
         */
        NeedRealDeviceName = 2,
    };
    /**
     * Stores a combination of #DetailsNeededFlag values.
     */
    Q_DECLARE_FLAGS(DetailsNeededFlags, DetailsNeededFlag)

    /**
     * This function gives a list of all possible mountpoints. (fstab)
     * @param infoNeeded Flags that specify which additional information
     * should be fetched.
     */
    static List possibleMountPoints(DetailsNeededFlags infoNeeded = BasicInfoNeeded);

    /**
     * Returns a list of all current mountpoints.
     *
     * @param infoNeeded Flags that specify which additional information
     * should be fetched.
     *
     * @note This method will return an empty list on @c Android
     */
    static List currentMountPoints(DetailsNeededFlags infoNeeded = BasicInfoNeeded);

    /**
     * Where this filesystem gets mounted from.
     * This can refer to a device, a remote server or something else.
     */
    QString mountedFrom() const;

    /**
     * Returns @c true if this mount point represents a network filesystem (e.g.\ NFS,
     * CIFS, etc.), otherwise returns @c false.
     *
     * @since 5.86
     */
    bool isOnNetwork() const;

    /**
     * Returns the device ID (dev_t, major, minor) of this mount point. This
     * ID is unique per device (including network mounts).
     *
     * @since 5.86
     */
    dev_t deviceId() const;

    /**
     * Canonical name of the device where the filesystem got mounted from.
     * (Or empty, if not a device)
     * Only available when the NeedRealDeviceName flag was set.
     */
    QString realDeviceName() const;

    /**
     * Path where the filesystem is mounted (if you used @ref currentMountPoints()),
     * or can be mounted (if you used @ref possibleMountPoints()).
     */
    QString mountPoint() const;

    /**
     * Type of filesystem
     */
    QString mountType() const;

    /**
     * Options used to mount the filesystem.
     * Only available if the @ref NeedMountOptions flag was set.
     */
    QStringList mountOptions() const;

    /**
     * Returns @c true if the filesystem is "probably" slow, e.g.\ a network mount,
     * @c false otherwise.
     */
    bool probablySlow() const;

    enum FileSystemFlag {
        SupportsChmod,
        SupportsChown,
        SupportsUTime,
        SupportsSymlinks,
        CaseInsensitive,
    };

    /**
     * Checks the capabilities of the filesystem.
     * @param flag the flag to check
     * @return true if the filesystem has that flag, false if not
     *
     * The available flags are:
     * @li SupportsChmod: returns true if the filesystem supports chmod
     * (e.g. msdos filesystems return false)
     * @li SupportsChown: returns true if the filesystem supports chown
     * (e.g. msdos filesystems return false)
     * @li SupportsUtime: returns true if the filesystems supports utime
     * (e.g. msdos filesystems return false)
     * @li SupportsSymlinks: returns true if the filesystems supports symlinks
     * (e.g. msdos filesystems return false)
     * @li CaseInsensitive: returns true if the filesystem treats
     * "foo" and "FOO" as being the same file (true for msdos filesystems)
     *
     */
    bool testFileSystemFlag(FileSystemFlag flag) const;

    /**
     * Destructor
     */
    ~KMountPoint();

private:
    /**
     * Constructor
     */
    KIOCORE_NO_EXPORT KMountPoint();

    friend KIOCORE_EXPORT QDebug operator<<(QDebug debug, const Ptr &mp);

    friend KMountPointPrivate;
    std::unique_ptr<KMountPointPrivate> d;
};

KIOCORE_EXPORT QDebug operator<<(QDebug debug, const KMountPoint::Ptr &mp);

Q_DECLARE_OPERATORS_FOR_FLAGS(KMountPoint::DetailsNeededFlags)

#endif // KMOUNTPOINT_H