Ichthyostega
c5292dd0dd
Since C++17 we can use the std::filesystem instead (and we ''do use it'' indeed) - relocate the `/lib/file.hpp` header - adapt the self-discovery of the executable to using std::filesystem Furthermore, some recherche regarding XVideo and Video Output
117 lines
3.1 KiB
C++
117 lines
3.1 KiB
C++
/*
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FILE.hpp - Filesystem access and helpers
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Copyright (C)
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2022, Hermann Vosseler <Ichthyostega@web.de>
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**Lumiera** is free software; you can redistribute it and/or modify it
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under the terms of the GNU General Public License as published by the
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Free Software Foundation; either version 2 of the License, or (at your
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option) any later version. See the file COPYING for further details.
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*/
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/** @file file.hpp
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** Includes the C++ Filesystem library and provides some convenience helpers.
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** The `std::filesystem` library allows for portable access to file and directory handling
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** functions; this header maps these functions with an concise `fs::` namespace prefix,
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** and offers some convenience extensions, which are _„slightly non-portable“_ (meaning they
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** were developed on Linux and „should“ work on Unix like systems; adapters for exotic operating
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** systems could be added here when necessary...)
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**
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** @todo 3/2024 should be part of generic utilities
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*/
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#ifndef LIB_FILE_H
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#define LIB_FILE_H
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#include "lib/error.hpp"
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#include "lib/symbol.hpp"
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#include "lib/meta/util.hpp"
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#include <filesystem>
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#include <cstdlib>
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namespace fs = std::filesystem;
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namespace std::filesystem {
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extern const string UNIX_HOMEDIR_SYMBOL;
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extern lib::Literal UNIX_HOMEDIR_ENV;
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inline fs::path
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getHomePath()
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{
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auto home = std::getenv(UNIX_HOMEDIR_ENV);
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if (not home)
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throw lumiera::error::Config{"Program environment doesn't define $HOME (Unix home directory)."};
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return fs::path{home};
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}
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/** resolves symlinks, `~` (Unix home dir) and relative specs
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* @return absolute canonical form if the path exists;
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* otherwise only the home directory is expanded */
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inline fs::path
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consolidated (fs::path rawPath)
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{
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if (rawPath.empty())
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return rawPath;
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if (UNIX_HOMEDIR_SYMBOL == *rawPath.begin())
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rawPath = getHomePath() / rawPath.lexically_proximate(UNIX_HOMEDIR_SYMBOL);
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return fs::weakly_canonical(rawPath);
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}
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/** check if the denoted path \a p has at least the given permissions */
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inline bool
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has_perm (fs::path const& p, fs::perms permissionMask)
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{
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return (fs::status(p).permissions() & permissionMask) == permissionMask;
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}
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/** check if the owner has read permissions on the denoted file or directory */
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inline bool
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can_read (fs::path const& p)
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{
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return has_perm (p, fs::perms::owner_read);
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}
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inline bool
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can_write (fs::path const& p)
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{
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return has_perm (p, fs::perms::owner_write);
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}
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inline bool
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can_exec (fs::path const& p)
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{
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return has_perm (p, fs::perms::owner_exec);
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}
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}//(End)namespace fs
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namespace util {
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/** specialisation: render filesystem path as double quoted string */
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template<>
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struct StringConv<fs::path, void>
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{
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static std::string
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invoke (fs::path path) noexcept
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try {
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return "≺"+std::string{path}+"≻";
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}
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catch(...)
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{ return lib::meta::FAILURE_INDICATOR; }
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};
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}//(End)namespace util
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#endif /*LIB_FILE_H*/
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