libostd/ostd/filesystem.hh

205 lines
6.9 KiB
C++

/** @addtogroup Utilities
* @{
*/
/** @file filesystem.hh
*
* @brief Filesystem abstraction module.
*
* This module defines the namespace ostd::filesystem, which is either
* std::experimental::filesystem or std::filesystem depending on which
* is available. For portable applications, only use the subset of the
* module covered by both versions.
*
* It also provides range integration for directory iterators and
* ostd::format_traits specialization for std::filesystem::path.
*
* Additionally, it implements glob matching following POSIX with its
* own extensions (mainly recursive glob matching via `**`).
*
* @include glob.cc
* @include listdir.cc
*
* @copyright See COPYING.md in the project tree for further information.
*/
#ifndef OSTD_FILESYSTEM_HH
#define OSTD_FILESYSTEM_HH
#if __has_include(<filesystem>)
# include <filesystem>
namespace ostd {
namespace filesystem = std::filesystem;
}
#elif __has_include(<experimental/filesystem>)
# include <experimental/filesystem>
namespace ostd {
namespace filesystem = std::experimental::filesystem;
}
#else
# error "Unsupported platform"
#endif
#include <ostd/platform.hh>
#include <ostd/range.hh>
#include <ostd/format.hh>
namespace ostd {
/** @addtogroup Utilities
* @{
*/
/** @brief Range integration for std::filesystem::directory_iterator.
*
* Allows directory iterators to be made into ranges via ostd::iter().
*
* @see ostd::ranged_traits<filesystem::recursive_directory_iterator>
*/
template<>
struct ranged_traits<filesystem::directory_iterator> {
/** @brief The range type for the iterator. */
using range = iterator_range<filesystem::directory_iterator>;
/** @brief Creates a range for the iterator. */
static range iter(filesystem::directory_iterator const &r) {
return range{filesystem::begin(r), filesystem::end(r)};
}
};
/** @brief Range integration for std::filesystem::recursive_directory_iterator.
*
* Allows recursive directory iterators to be made into ranges via ostd::iter().
*
* @see ostd::ranged_traits<filesystem::directory_iterator>
*/
template<>
struct ranged_traits<filesystem::recursive_directory_iterator> {
/** @brief The range type for the iterator. */
using range = iterator_range<filesystem::recursive_directory_iterator>;
/** @brief Creates a range for the iterator. */
static range iter(filesystem::recursive_directory_iterator const &r) {
return range{filesystem::begin(r), filesystem::end(r)};
}
};
/** @brief ostd::format_traits specialization for std::filesystem::path.
*
* This allows paths to be formatted as strings. The value is formatted
* as if `path.string()` was formatted, using the exact ostd::format_spec.
*/
template<>
struct format_traits<filesystem::path> {
/** @brief Formats the path's string value.
*
* This calls exactly
*
* ~~~{.cc}
* fs.format_value(writer, p.string());
* ~~~
*/
template<typename R>
static void to_format(
filesystem::path const &p, R &writer, format_spec const &fs
) {
fs.format_value(writer, p.string());
}
};
namespace detail {
OSTD_EXPORT bool glob_match_filename_impl(
typename filesystem::path::value_type const *fname,
typename filesystem::path::value_type const *wname
) noexcept;
OSTD_EXPORT void glob_match_impl(
void (*out)(filesystem::path const &, void *),
typename filesystem::path::iterator beg,
typename filesystem::path::iterator &end,
filesystem::path pre, void *data
);
} /* namespace detail */
/** @brief Checks if the given path matches the given glob pattern.
*
* This matches the given filename against POSIX-style glob patterns.
* The following patterns are supported:
*
* | Pattern | Description |
* |---------|----------------------------------------------------|
* | * | 0 or more characters |
* | ? | any single character |
* | [abc] | one character in the brackets |
* | [a-z] | one character within the range in the brackets |
* | [!abc] | one character not in the brackets |
* | [!a-z] | one character not within the range in the brackets |
*
* The behavior is the same as in POSIX. You can combine ranges and
* individual characters in the `[]` pattern together as well as define
* multiple ranges in one (e.g. `[a-zA-Z_?]` matching alphabetics,
* an underscore and a question mark). The behavior of the range varies
* by locale. If the second character in the range is lower in value
* than the first one, a match will never happen. To match the `]`
* character in the brackets, make it the first one. To match the
* dash character, make it the first or the last.
*
* You can also use the brackets to escape metacharacters. So to
* match a literal `*`, use `[*]`.
*
* Keep in mind that an invalid bracket syntax (unterminated) will
* always cause this to return `false`.
*
* This function is used in ostd::glob_match().
*/
inline bool glob_match_filename(
filesystem::path const &filename, filesystem::path const &pattern
) noexcept {
return detail::glob_match_filename_impl(filename.c_str(), pattern.c_str());
}
/** @brief Expands a path with glob patterns.
*
* Individual expanded paths are put in `out` and are of the standard
* std::filesystem::path type. It supports standard patterns as defined
* in ostd::glob_match_filename().
*
* So for example, `*.cc` will expand to `one.cc`, `two.cc` and so on.
* A pattern like `foo/[cb]at.txt` will match `foo/cat.txt` and `foo/bat.txt`
* but not `foo/Cat.txt`. The `foo/?at.txt` will match `foo/cat.txt`,
* `foo/Cat.txt`, `foo/pat.txt`, `foo/vat.txt` or any other character
* in the place.
*
* Additionally, a special `**` pattern is also supported which is not
* matched by ostd::glob_match_filename(). It's only allowed if the entire
* filename or directory name is `**`. When used as a directory name, it
* will expand to all directories in the location and all subdirectories
* of those directories. If used as a filename (at the end of the path),
* then it expands to directories and subdirectories aswell as all files
* in the location and in the directories or subdirectories. Keep in mind
* that it is not a regular pattern and a `**` when found in a regular
* context (i.e. not as entire filename/directory name) will be treated
* as two regular `*` patterns.
*
* @throws std::filesystem_error if a filesystem error occurs.
* @returns The forwarded `out`.
*/
template<typename OutputRange>
inline OutputRange &&glob_match(
OutputRange &&out, filesystem::path const &path
) {
auto pend = path.end();
detail::glob_match_impl([](filesystem::path const &p, void *outp) {
static_cast<std::remove_reference_t<OutputRange> *>(outp)->put(p);
}, path.begin(), pend, filesystem::path{}, &out);
return std::forward<OutputRange>(out);
}
/** @} */
} /* namespace ostd */
#endif
/** @} */