/*
* This program source code file is part of KiCad, a free EDA CAD application.
*
* Copyright (C) 2023 KiCad Developers, see AUTHORS.txt for contributors.
*
* This program 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 2
* of the License, or (at your option) any later version.
*
* This program 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, you may find one here:
* http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
* or you may search the http://www.gnu.org website for the version 2 license,
* or you may write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
*/
/**
* File locking utilities
* @file lockfile.h
*/
#ifndef INCLUDE__LOCK_FILE_H_
#define INCLUDE__LOCK_FILE_H_
#include <wx/wx.h>
#include <wx/file.h>
#include <wx/filefn.h>
#include <wx/log.h>
#include <wx/filename.h>
#include <nlohmann/json.hpp>
#include <wildcards_and_files_ext.h>
#define LCK "KICAD_LOCKING"
class LOCKFILE
{
public:
LOCKFILE( const wxString &filename, bool aRemoveOnRelease = true ) :
m_originalFile( filename ), m_fileCreated( false ), m_status( false ),
m_removeOnRelease( aRemoveOnRelease ), m_errorMsg( "" )
{
if( filename.IsEmpty() )
return;
wxLogTrace( LCK, "Trying to lock %s", filename );
wxFileName fn( filename );
fn.SetName( FILEEXT::LockFilePrefix + fn.GetName() );
fn.SetExt( fn.GetExt() + '.' + FILEEXT::LockFileExtension );
if( !fn.IsDirWritable() )
{
wxLogTrace( LCK, "File is not writable: %s", filename );
m_status = true;
m_removeOnRelease = false;
return;
}
m_lockFilename = fn.GetFullPath();
wxFile file;
try
{
bool lock_success = false;
bool rw_success = false;
{
wxLogNull suppressExpectedErrorMessages;
lock_success = file.Open( m_lockFilename, wxFile::write_excl );
if( !lock_success )
rw_success = file.Open( m_lockFilename, wxFile::read );
}
if( lock_success )
{
// Lock file doesn't exist, create one
m_fileCreated = true;
m_status = true;
m_username = wxGetUserId();
m_hostname = wxGetHostName();
nlohmann::json j;
j["username"] = std::string( m_username.mb_str() );
j["hostname"] = std::string( m_hostname.mb_str() );
std::string lock_info = j.dump();
file.Write( lock_info );
file.Close();
wxLogTrace( LCK, "Locked %s", filename );
}
else if( rw_success )
{
// Lock file already exists, read the details
wxString lock_info;
file.ReadAll( &lock_info );
nlohmann::json j = nlohmann::json::parse( std::string( lock_info.mb_str() ) );
m_username = wxString( j["username"].get<std::string>() );
m_hostname = wxString( j["hostname"].get<std::string>() );
file.Close();
m_errorMsg = _( "Lock file already exists" );
wxLogTrace( LCK, "Existing Lock for %s", filename );
}
else
{
throw std::runtime_error( "Failed to open lock file" );
}
}
catch( std::exception& e )
{
wxLogError( "Got an error trying to lock %s: %s", filename, e.what() );
// Delete lock file if it was created above but we threw an exception somehow
if( m_fileCreated )
{
wxRemoveFile( m_lockFilename );
m_fileCreated = false; // Reset the flag since file has been deleted manually
}
m_errorMsg = _( "Failed to access lock file" );
m_status = false;
}
}
~LOCKFILE()
{
UnlockFile();
}
/**
* Unlocks and removes the file from the filesystem as long as we still own it.
*/
void UnlockFile()
{
wxLogTrace( LCK, "Unlocking %s", m_lockFilename );
// Delete lock file only if the file was created in the constructor and if the file contains the correct user and host names
if( m_fileCreated && checkUserAndHost() )
{
if( m_removeOnRelease )
wxRemoveFile( m_lockFilename );
m_fileCreated = false; // Reset the flag since file has been deleted manually
m_status = false;
m_errorMsg = wxEmptyString;
}
}
/**
* Forces the lock, overwriting the data that existed already
* @return True if we successfully overrode the lock
*/
bool OverrideLock( bool aRemoveOnRelease = true )
{
wxLogTrace( LCK, "Overriding lock on %s", m_lockFilename );
if( !m_fileCreated )
{
try
{
wxFile file;
bool success = false;
{
wxLogNull suppressExpectedErrorMessages;
success = file.Open( m_lockFilename, wxFile::write );
}
if( success )
{
m_username = wxGetUserId();
m_hostname = wxGetHostName();
nlohmann::json j;
j["username"] = std::string( m_username.mb_str() );
j["hostname"] = std::string( m_hostname.mb_str() );
std::string lock_info = j.dump();
file.Write( lock_info );
file.Close();
m_fileCreated = true;
m_status = true;
m_removeOnRelease = aRemoveOnRelease;
m_errorMsg = wxEmptyString;
wxLogTrace( LCK, "Successfully overrode lock on %s", m_lockFilename );
return true;
}
return false;
}
catch( std::exception& e )
{
wxLogError( "Got exception trying to override lock on %s: %s",
m_lockFilename, e.what() );
return false;
}
}
else
{
wxLogTrace( LCK, "Upgraded lock on %s to delete on release", m_lockFilename );
m_removeOnRelease = aRemoveOnRelease;
}
return true;
}
bool IsLockedByMe()
{
return m_username == wxGetUserId() && m_hostname == wxGetHostName();
}
/**
* @return Current username. If we own the lock, this is us. Otherwise, this is the user that does own it
*/
wxString GetUsername(){ return m_username; }
/**
* @return Current hostname. If we own the lock this is our computer. Otherwise, this is the computer that does
*/
wxString GetHostname(){ return m_hostname; }
/**
* @return Last error message generated
*/
wxString GetErrorMsg(){ return m_errorMsg; }
bool Locked() const
{
return m_fileCreated;
}
bool Valid() const
{
return m_status;
}
explicit operator bool() const
{
return m_status;
}
private:
wxString m_originalFile;
wxString m_lockFilename;
wxString m_username;
wxString m_hostname;
bool m_fileCreated;
bool m_status;
bool m_removeOnRelease;
wxString m_errorMsg;
bool checkUserAndHost()
{
wxFileName fileName( m_lockFilename );
if( !fileName.FileExists() )
{
wxLogTrace( LCK, "File does not exist: %s", m_lockFilename );
return false;
}
wxFile file;
try
{
if( file.Open( m_lockFilename, wxFile::read ) )
{
wxString lock_info;
file.ReadAll( &lock_info );
nlohmann::json j = nlohmann::json::parse( std::string( lock_info.mb_str() ) );
if( m_username == wxString( j["username"].get<std::string>() )
&& m_hostname == wxString( j["hostname"].get<std::string>() ) )
{
wxLogTrace( LCK, "User and host match for lock %s", m_lockFilename );
return true;
}
}
}
catch( std::exception &e )
{
wxLogError( "Got exception trying to check user/host for lock on %s: %s",
m_lockFilename,
e.what() );
}
wxLogTrace( LCK, "User and host DID NOT match for lock %s", m_lockFilename );
return false;
}
};
#endif // INCLUDE__LOCK_FILE_H_