fileMonitor.H

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/*---------------------------------------------------------------------------*\
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-------------------------------------------------------------------------------
    Copyright (C) 2011-2015 OpenFOAM Foundation
    Copyright (C) 2017-2020 OpenCFD Ltd.
-------------------------------------------------------------------------------
License
    This file is part of OpenFOAM.
 
    OpenFOAM 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.
 
    OpenFOAM 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 OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.
 
Class
    Foam::fileMonitor
 
Description
    Checking for changes to files.
 
Note
    The default is to use stat to get the timestamp.
 
    Compile with FOAM_USE_INOTIFY to use the inotify
    (Linux specific, since 2.6.13) framework. The problem is that inotify does
    not work on nfs3 mounted directories!!
 
SourceFiles
    fileMonitor.C
 
\*---------------------------------------------------------------------------*/
 
#ifndef Foam_fileMonitor_H
#define Foam_fileMonitor_H
 
#include "DynamicList.H"
#include <memory>
#include <sys/types.h>
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
namespace Foam
{
 
// Forward Declarations
class fileMonitor;
class fileMonitorWatcher;
template<class EnumType> class Enum;
 
/*---------------------------------------------------------------------------*\
                         Class fileMonitor Declaration
\*---------------------------------------------------------------------------*/
 
class fileMonitor
{
public:
 
    // Public Data Types
 
        //- Enumeration defining the file state.
        enum fileState
        {
            UNMODIFIED = 0,
            MODIFIED = 1,
            DELETED = 2
        };
 
        static const Enum<fileState> fileStateNames_;
 
private:
 
    // Private Data
 
        //- Whether to use inotify (requires -DFOAM_USE_INOTIFY, see above)
        const bool useInotify_;
 
        //- State for all watchFds based on local files
        mutable DynamicList<fileState> localState_;
 
        //- State for all watchFds - synchronised
        mutable DynamicList<fileState> state_;
 
        //- Filename for all watchFds
        DynamicList<fileName> watchFile_;
 
        //- Free watchFds
        DynamicList<label> freeWatchFds_;
 
        //- Watch mechanism (stat or inotify)
        mutable std::unique_ptr<fileMonitorWatcher> watcher_;
 
 
    // Private Member Functions
 
        //- Update localState_ from any events.
        void checkFiles() const;
 
        //- No copy construct
        fileMonitor(const fileMonitor&) = delete;
 
        //- No copy assignment
        void operator=(const fileMonitor&) = delete;
 
 
public:
 
    //- Named/registered debug switch: 'fileMonitor'
    static int debug;
 
 
    // Constructors
 
        //- Construct with specified inotify use
        explicit fileMonitor(const bool useInotify);
 
 
    //- Destructor
    ~fileMonitor();
 
 
    // Member Functions
 
        //- Add file to watch. Return watch descriptor
        label addWatch(const fileName&);
 
        //- Remove file to watch. Return true if successful
        bool removeWatch(const label watchFd);
 
        //- Get name of file being watched
        const fileName& getFile(const label watchFd) const;
 
        //- Check state using handle
        fileState getState(const label watchFd) const;
 
        //- Check state of all files. Updates state_.
        void updateStates
        (
            const bool masterOnly,
            const bool syncPar
        ) const;
 
        //- Reset state (e.g. after having read it) using handle
        void setUnmodified(const label watchFd);
};
 
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
} // End namespace Foam
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
#endif
 
// ************************************************************************* //