LUMIERA.clone/src/lib/searchpath.hpp

148 lines
4.5 KiB
C++

/*
SEARCHPATH.hpp - helpers for searching directory lists and locating modules
Copyright (C) Lumiera.org
2011, Hermann Vosseler <Ichthyostega@web.de>
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, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#ifndef COMMON_SEARCHPATH_H
#define COMMON_SEARCHPATH_H
#include "lib/error.hpp"
#include "lib/bool-checkable.hpp"
#include <boost/noncopyable.hpp>
#include <boost/filesystem.hpp>
#include <boost/regex.hpp>
#include <string>
namespace lib {
using std::string;
using boost::regex;
using boost::smatch;
using boost::regex_search;
using boost::sregex_iterator;
typedef smatch::value_type const& SubMatch;
namespace error = lumiera::error;
namespace fsys = boost::filesystem;
LUMIERA_ERROR_DECLARE (FILE_NOT_DIRECTORY); ///< path element points at a file instead of a directory
using error::LUMIERA_ERROR_ITER_EXHAUST;
/** retrieve the location of the executable */
string findExePath();
/**
* Helper: Access a path Specification as a sequence of filesystem Paths.
* This iterator class dissects a ':'-separated path list. The individual
* components may use the symbol \c $ORIGIN to denote the directory holding
* the current executable. After resolving this symbol, a valid absolute or
* relative filesystem path should result, which must not denote an existing
* file (directory is OK).
* @note #fetch picks the current component and advances the iteration.
*/
class SearchPathSplitter
: public BoolCheckable<SearchPathSplitter
, boost::noncopyable>
{
string pathSpec_;
sregex_iterator pos_,
end_;
static regex EXTRACT_PATHSPEC;
public:
SearchPathSplitter (string const& searchPath)
: pathSpec_(searchPath)
, pos_(pathSpec_.begin(),pathSpec_.end(), EXTRACT_PATHSPEC)
, end_()
{ }
bool
isValid() const
{
return pos_ != end_;
}
string
next ()
{
if (!isValid())
throw error::Logic ("Search path exhausted."
,LUMIERA_ERROR_ITER_EXHAUST);
string currentPathElement = resolveRelative();
++pos_;
return currentPathElement;
}
private:
/** maybe resolve a path spec given relative to
* the current Executable location ($ORIGIN) */
string
resolveRelative ()
{
if (containsORIGINToken())
return asAbsolutePath();
else
return getFullPath();
}
SubMatch found(int group=0) { return (*pos_)[group]; }
bool containsORIGINToken() { return found(1).matched; }
string getRelativePath() { return found(2); }
string getFullPath() { return found(); }
string
asAbsolutePath()
{
fsys::path exePathName (findExePath());
fsys::path modPathName (exePathName.remove_leaf() / getRelativePath());
if (fsys::exists(modPathName) && !fsys::is_directory (modPathName))
throw error::Invalid ("Error in search path: component \""+modPathName.string()+"\" is not a directory"
,LUMIERA_ERROR_FILE_NOT_DIRECTORY);
return modPathName.directory_string();
}
};
/** helper to establish the location to search for loadable modules,
* configuration files, icons and further resources. After first trying
* the moduleName directly, the given search path is walked using the
* SearchPathSplitter, until encountering an existing file with the
* given name.
* @return the absolute pathname of the module file found
* @throws error::Config when the resolution fails
*/
string resolveModulePath (string moduleName, string searchPath = "");
} // namespace lib
#endif