Ichthyostega
a90b9e5f16
In the Lumiera code base, we use C-String constants as unique error-IDs. Basically this allows to create new unique error IDs anywhere in the code. However, definition of such IDs in arbitrary namespaces tends to create slight confusion and ambiguities, while maintaining the proper use statements requires some manual work. Thus I introduce a new **standard scheme** * Error-IDs for widespread use shall be defined _exclusively_ into `namespace lumiera::error` * The shorthand-Macro `LERR_()` can now be used to simplify inclusion and referral * (for local or single-usage errors, a local or even hidden definition is OK)
123 lines
3.6 KiB
C++
123 lines
3.6 KiB
C++
/*
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SEARCHPATH.hpp - helpers for searching directory lists and locating modules
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Copyright (C) Lumiera.org
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2011, Hermann Vosseler <Ichthyostega@web.de>
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License as
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published by the Free Software Foundation; either version 2 of
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the License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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/** @file searchpath.hpp
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** Helpers to handle directory search paths.
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** The SerachPathSplitter allows to evaluate a "path" like specification
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** with colon separated components. It is complemented by some magic convenience
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** functions to self-discover the currently running executable and to resolve
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** the `$ORIGIN` pattern similar to what is known from linker `rpath` / `runpath`
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*/
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#ifndef COMMON_SEARCHPATH_H
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#define COMMON_SEARCHPATH_H
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#include "lib/error.hpp"
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#include "lib/nocopy.hpp"
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#include <boost/filesystem.hpp>
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#include <string>
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#include <regex>
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namespace lib {
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using std::string;
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using SubMatch = std::smatch::value_type const&;
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namespace error = lumiera::error;
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namespace fsys = boost::filesystem;
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using LERR_(ITER_EXHAUST);
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/** retrieve the location of the executable */
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string findExePath();
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/** replace $ORIGIN tokens in the given string
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* @return copy with expansions applied */
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string replaceMagicLinkerTokens (string const& src);
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/**
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* Helper: Access a path Specification as a sequence of filesystem Paths.
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* This iterator class dissects a ':'-separated path list. The individual
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* components may use the symbol \c $ORIGIN to refer to the directory
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* holding the current executable.
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* @note #next picks the current component and advances the iteration.
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*/
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class SearchPathSplitter
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: util::NonCopyable
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{
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string pathSpec_;
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std::sregex_iterator pos_,
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end_;
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static const std::regex EXTRACT_PATHSPEC;
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public:
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SearchPathSplitter (string const& searchPath)
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: pathSpec_(replaceMagicLinkerTokens (searchPath))
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, pos_(pathSpec_.begin(),pathSpec_.end(), EXTRACT_PATHSPEC)
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, end_()
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{ }
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explicit operator bool() const { return isValid(); }
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bool
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isValid() const
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{
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return pos_ != end_;
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}
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string
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next ()
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{
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if (!isValid())
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throw error::Logic ("Search path exhausted."
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,LERR_(ITER_EXHAUST));
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string currentPathElement = pos_->str();
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++pos_;
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return currentPathElement;
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}
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};
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/** helper to establish the location to search for loadable modules,
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* configuration files, icons and further resources. After first trying
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* the moduleName directly, the given search path is walked using the
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* SearchPathSplitter, until encountering an existing file with the
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* given name.
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* @return the absolute pathname of the module file found
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* @throws error::Config when the resolution fails
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*/
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string resolveModulePath (fsys::path moduleName, string searchPath = "");
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} // namespace lib
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#endif
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