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Updated readme.

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@ -19,7 +19,7 @@ had reports of it being used on iOS (within sandboxing constraints).
It is of course in its own namespace `ghc::filesystem` to not interfere with a regular `std::filesystem` should you use it in a mixed C++17 It is of course in its own namespace `ghc::filesystem` to not interfere with a regular `std::filesystem` should you use it in a mixed C++17
environment (which is possible). environment (which is possible).
*Test coverage is well above 90%, and starting with v1.3.6 *Test coverage is well above 90%, and starting with v1.3.6 and in v1.5.0
more time was invested in benchmarking and optimizing parts of the library. I'll try more time was invested in benchmarking and optimizing parts of the library. I'll try
to continue to optimize some parts and refactor others, striving to continue to optimize some parts and refactor others, striving
to improve it as long as it doesn't introduce additional C++17/C++20 compatibility to improve it as long as it doesn't introduce additional C++17/C++20 compatibility
@ -68,10 +68,10 @@ where full C++17 or C++20 is available, it doesn't try to be a "better"
`std::filesystem`, just an almost drop-in if you can't use it (with the exception `std::filesystem`, just an almost drop-in if you can't use it (with the exception
of the UTF-8 preference). of the UTF-8 preference).
This implementation is following the ["UTF-8 Everywhere" philosophy](https://utf8everywhere.org/) in that all :information_source: **Important:** _This implementation is following the ["UTF-8 Everywhere" philosophy](https://utf8everywhere.org/) in that all
`std::string` instances will be interpreted the same as `std::u8string` encoding `std::string` instances will be interpreted the same as `std::u8string` encoding
wise and as being in UTF-8. The `std::u16string` will be seen as UTF-16. See *Differences in API* wise and as being in UTF-8. The `std::u16string` will be seen as UTF-16. See *Differences in API*
for more information. for more information._
Unit tests are currently run with: Unit tests are currently run with:
@ -187,14 +187,13 @@ Now you have e.g. `fs::ofstream out(somePath);` and it is either the wrapper or
the C++17 `std::ofstream`. the C++17 `std::ofstream`.
**Be aware, as a header-only library, it is not hiding the fact, that it **Be aware, as a header-only library, it is not hiding the fact, that it
uses system includes, so they "pollute" your global namespace.** uses system includes, so they "pollute" your global namespace. Use the
forwarding-/implementation-header based approach (see below) to avoid this.**
:information_source: **Hint:** There is an additional header named `ghc/fs_std.hpp` that implements this :information_source: **Hint:** There is an additional header named `ghc/fs_std.hpp` that implements this
dynamic selection of a filesystem implementation, that you can include dynamic selection of a filesystem implementation, that you can include
instead of `ghc/filesystem.hpp` when you want std::filesystem where instead of `ghc/filesystem.hpp` when you want std::filesystem where
available and ghc::filesystem where not. It also enables the `wchar_t` available and ghc::filesystem where not.
support on `ghc::filesystem` on Windows, so the resulting implementation
in the `fs` namespace will be compatible.
### Using it as Forwarding-/Implementation-Header ### Using it as Forwarding-/Implementation-Header
@ -284,7 +283,7 @@ There is a version macro `GHC_FILESYSTEM_VERSION` defined in case future changes
might make it needed to react on the version, but I don't plan to break anything. might make it needed to react on the version, but I don't plan to break anything.
It's the version as decimal number `(major * 10000 + minor * 100 + patch)`. It's the version as decimal number `(major * 10000 + minor * 100 + patch)`.
**Note:** Starting from v1.0.2 only even patch versions will be used for releases :information_source: **Note:** Only even patch versions will be used for releases
and odd patch version will only be used for in between commits while working on and odd patch version will only be used for in between commits while working on
the next version. the next version.
@ -302,8 +301,8 @@ are only supported on C++17. When Compiling with C++20, `ghc::filesysytem`
defaults to the C++20 API, with the `char8_t` and `std::u8string` interfaces defaults to the C++20 API, with the `char8_t` and `std::u8string` interfaces
and the deprecated `fs::u8path` factory method. and the deprecated `fs::u8path` factory method.
**Note:** If the C++17 API should be enforced even in C++20 mode, use the define :information_source: **Note:** If the C++17 API should be enforced even in C++20 mode,
`GHC_FILESYSTEM_ENFORCE_CPP17_API`. use the define `GHC_FILESYSTEM_ENFORCE_CPP17_API`.
Even then it is possible to create `fws::path` from `std::u8string` but Even then it is possible to create `fws::path` from `std::u8string` but
`fs::path::u8string()` and `fs::path::generic_u8string()` return normal `fs::path::u8string()` and `fs::path::generic_u8string()` return normal
UTF-8 encoded `std::string` instances, so code written for C++17 could UTF-8 encoded `std::string` instances, so code written for C++17 could
@ -361,8 +360,8 @@ change anything. I still need to investigate this.
## Differences ## Differences
As this implementation is based on existing code from my private helper As this implementation is based on existing code from my private helper
classes, it derived some constraints of it, leading to some differences classes, it derived some constraints of it. Starting from v1.5.0 most of the
between this and the standard C++17/C++20 API. differences between this and the standard C++17/C++20 API where removed.
### LWG Defects ### LWG Defects
@ -398,7 +397,7 @@ These are not implemented under C++11 and C++14, as there is no
`std::basic_string_view` available and I did want to keep this `std::basic_string_view` available and I did want to keep this
implementation self-contained and not write a full C++17-upgrade for implementation self-contained and not write a full C++17-upgrade for
C++11/14. Starting with v1.1.0 these are supported when compiling C++11/14. Starting with v1.1.0 these are supported when compiling
ghc::filesystem under C++17. ghc::filesystem under C++17 of C++20.
### Differences in API ### Differences in API
@ -413,43 +412,21 @@ seen as unicode codepoints. Depending on the size of `std::wstring` characters,
#### Differences of Specific Interfaces #### Differences of Specific Interfaces
```cpp Starting with v1.5.0 `ghc::filesystem` is following the C++17 standard in
filesystem::path::string_type using `wchar_t` and `std::wstring` on Windows as the types internally used
filesystem::path::value_type for path representation. It is still possible to get the old behavior by defining
``` `GHC_WIN_DISABLE_WSTRING_STORAGE_TYPE` and get `filesystem::path::string_type` as
`std::string` and `filesystem::path::value_type` as `wchar_t`.
In Windows, an implementation should use `std::wstring` and `wchar_t` as types used If you need to call some Windows API, with v1.5.0 and above, simply
for the native representation, but as I'm a big fan of the use the W-variant of the Windows-API call (e.g. `GetFileAttributesW(p.c_str())`).
["UTF-8 Everywhere" philosophy](https://utf8everywhere.org/), I decided
agains it for now. If you need to call some Windows API, use the W-variant :information_source: **Note:** _When using the old behavior by defining
with the `path::wstring()` member `GHC_WIN_DISABLE_WSTRING_STORAGE_TYPE`, use the `path::wstring()` member
(e.g. `GetFileAttributesW(p.wstring().c_str())`). This gives you the (e.g. `GetFileAttributesW(p.wstring().c_str())`). This gives you the
Unicode variant independant of the `UNICODE` macro and makes sharing code Unicode variant independant of the `UNICODE` macro and makes sharing code
between Windows, Linux and macOS easier. between Windows, Linux and macOS easier and works with `std::filesystem` and
`ghc::filesystem`._
Starting with v1.2.0 `ghc::filesystem` has the option to select the more
standard conforming APi with `wchar_t` and `std::wstring` on Windows by
defining `GHC_WIN_WSTRING_STRING_TYPE`. This define has no effect on other
platforms and will be set by the helping headers `ghc/fs_std.hpp` and
the pair `ghc/fs_std_fwd.hpp`/`ghc/fs_std_impl.hpp` to enhance compatibility.
```cpp
const path::string_type& path::native() const /*noexcept*/;
const path::value_type *path::c_str() const /*noexcept*/;
```
These two can not be `noexcept` with the current implementation. This due
to the fact, that internally path is working on the generic path version
only, and the getters need to do a conversion to native path format.
```cpp
const path::string_type& path::generic_string() const;
```
This returns a const reference, instead of a value, because it can. This
implementation uses the generic representation for internal workings, so
it's "free" to return that.
```cpp ```cpp
std::string path::u8string() const; std::string path::u8string() const;
@ -462,7 +439,7 @@ std::u8string path::generic_u8string() const;
The return type of these two methods is depending on the used C++ standard The return type of these two methods is depending on the used C++ standard
and if `GHC_FILESYSTEM_ENFORCE_CPP17_API` is defined. On C++11, C++14 and and if `GHC_FILESYSTEM_ENFORCE_CPP17_API` is defined. On C++11, C++14 and
C++17 or when `GHC_FILESYSTEM_ENFORCE_CPP17_API` is defined, the return C++17 or when `GHC_FILESYSTEM_ENFORCE_CPP17_API` is defined, the return
type is `std::string`, and on C++20 without the define it is `std::u8string`. type is `std::string`, and on C++20 without the define it is `std::u8string`.
### Differences in Behavior ### Differences in Behavior
@ -502,34 +479,9 @@ ASSERT(p1 == p2);
For all non-host-leading paths the behaviour will match the one described by For all non-host-leading paths the behaviour will match the one described by
the standard. the standard.
#### fs.op.copy ([ref](https://en.cppreference.com/w/cpp/filesystem/copy))
Then there is `fs::copy`. The tests in the suite fail partially with C++17 `std::filesystem`
on GCC/Clang. They complain about a copy call with `fs::copy_options::recursive` combined
with `fs::copy_options::create_symlinks` or `fs::copy_options::create_hard_links` if the
source is a directory. There is nothing in the standard that forbids this combination
and it is the only way to deep-copy a tree while only create links for the files.
There is [LWG #2682](https://wg21.cmeerw.net/lwg/issue2682) that supports this
interpretation, but the issue ignores the usefulness of the combination with recursive
and part of the justification for the proposed solution is "we did it so for almost two years".
But this makes `fs::copy` with `fs::copy_options::create_symlinks` or `fs::copy_options::create_hard_links`
just a more complicated syntax for the `fs::create_symlink` or `fs::create_hardlink` operation
and I don't want to believe, that this was the intention of the original writing.
As there is another issue related to copy, with a different take on the description.
**Note:** With v1.1.2 I decided to integrate a behavior switch for this and make the LWG #2682
the default.
## Open Issues ## Open Issues
### General Known Issues
There are still some methods that break the `noexcept` clause, some
are related to LWG defects, some are due to my implementation. I
work on fixing the later ones, and might in cases where there is no
way of implementing the feature without risk of an exception, break
conformance and remove the `noexcept`.
### Windows ### Windows
#### Symbolic Links on Windows #### Symbolic Links on Windows
@ -552,8 +504,37 @@ to the expected behavior.
## Release Notes ## Release Notes
### v1.4.2 (WIP) ### v1.5.0 (WIP)
* Fix for [#91](https://github.com/gulrak/filesystem/issues/91), the way
the CMake build options `GHC_FILESYSTEM_BUILD_TESTING`, `GHC_FILESYSTEM_BUILD_EXAMPLES`
and `GHC_FILESYSTEM_WITH_INSTALL` where implemented, prohibited setting them
from a parent project when using this via `add_subdirectory`, this fix
allows to set them again.
* Major refactoring for [#90](https://github.com/gulrak/filesystem/issues/90),
the way, the Windows version of `fs::path` was originally created from the
POSIX based implementation was, by adaption of the incoming and outgoing
strings. This resulted in a mutable cache inside `fs::path`on Windows, that
was inherently not thread-safe, even for `const` methods.
To not add additional patches to a suboptimal solution, this time I reworked
the `path` code to now store _native_ path-representation. This changed a
lot of code, but when combined with `wchar_t` as `value_type` helped to avoid
lots of conversion for calls to Win-API.<br>
As interfaces where changed, it had to be released in a new minor version.
The set of refactorings resulted in the following changes:
* `fs::path::native()` and `fs::path::c_str()` can now be `noexcept` as the
standard mandates
* On Windows `wchar_t` is now the default for `fs::path::value_type` and
`std::wstring` is the default für `fs::path::string_type`.
* This allows the implementation to call Win-API without allocating
conversions
* Thread-safety on `const` methods of `fs::path` is no longer an issue
* Some code could be simplified during this refactoring
* Automatic prefixing of long path on Windows can now be disabled with
defining `GHC_WIN_DISABLE_AUTO_PREFIXES`, for all other types of prefixes
or namespaces the behavior follows that of MSVC `std::filesystem::path`
* In case the old `char`/`std::string` based approach for Windows is still
needed, it can be activated with `GHC_WIN_DISABLE_WSTRING_STORAGE_TYPE`
* Enhancement for [#89](https://github.com/gulrak/filesystem/issues/89), `fs::file_status` * Enhancement for [#89](https://github.com/gulrak/filesystem/issues/89), `fs::file_status`
now supports `operator==` introduced in `std::filesystem` with C++20. now supports `operator==` introduced in `std::filesystem` with C++20.
* Refactoring for [#88](https://github.com/gulrak/filesystem/issues/88), `fs::path::parent_path()` * Refactoring for [#88](https://github.com/gulrak/filesystem/issues/88), `fs::path::parent_path()`
@ -564,16 +545,16 @@ to the expected behavior.
### [v1.4.0](https://github.com/gulrak/filesystem/releases/tag/v1.4.0) ### [v1.4.0](https://github.com/gulrak/filesystem/releases/tag/v1.4.0)
* Enhancements for [#71](https://github.com/gulrak/filesystem/issues/71), when compiled with C++20: * Enhancements for [#71](https://github.com/gulrak/filesystem/issues/71), when compiled with C++20:
* `char8_t` and `std::u8string` are supported where `Source` is the parameter type * `char8_t` and `std::u8string` are supported where `Source` is the parameter type
* `fs::path::u8string()` and `fs::path::generic_u8string()` now return a `std::u8string` * `fs::path::u8string()` and `fs::path::generic_u8string()` now return a `std::u8string`
* The _spaceship operator_ `<=>` is now supported for `fs::path` * The _spaceship operator_ `<=>` is now supported for `fs::path`
* With the define `GHC_FILESYSTEM_ENFORCE_CPP17_API` `ghc::filesystem` will fall back * With the define `GHC_FILESYSTEM_ENFORCE_CPP17_API` `ghc::filesystem` will fall back
to the old `fs::path::u8string()` and `fs::path::generic_u8string()` API if preferred to the old `fs::path::u8string()` and `fs::path::generic_u8string()` API if preferred
* Bugfix for `fs::proximate(p, ec)` where the internal call to `fs::current_path()` was not * Bugfix for `fs::proximate(p, ec)` where the internal call to `fs::current_path()` was not
using the `error_code` variant, throwing possible exceptions instead of setting `ec`. using the `error_code` variant, throwing possible exceptions instead of setting `ec`.
* Enhancement `LWG_2936_BEHAVIOUR` is now on by default. * Enhancement `LWG_2936_BEHAVIOUR` is now on by default.
* Some cleanup work to reduce preprocessor directives for better readability and remove unneeded * Some cleanup work to reduce preprocessor directives for better readability and remove unneeded
template specializations. template specializations.
### [v1.3.10](https://github.com/gulrak/filesystem/releases/tag/v1.3.10) ### [v1.3.10](https://github.com/gulrak/filesystem/releases/tag/v1.3.10)
@ -581,7 +562,7 @@ to the expected behavior.
handling `Source` parameters that are string views. handling `Source` parameters that are string views.
* Fix for [#79](https://github.com/gulrak/filesystem/issues/79), the bit operations * Fix for [#79](https://github.com/gulrak/filesystem/issues/79), the bit operations
for filesystem bitmasks that should be are now `constexpr`. for filesystem bitmasks that should be are now `constexpr`.
### [v1.3.8](https://github.com/gulrak/filesystem/releases/tag/v1.3.8) ### [v1.3.8](https://github.com/gulrak/filesystem/releases/tag/v1.3.8)
* Refactoring for [#78](https://github.com/gulrak/filesystem/issues/78), the dynamic * Refactoring for [#78](https://github.com/gulrak/filesystem/issues/78), the dynamic