This patch implements the `what()` for filesystem errors. The message
includes the 'what_arg', any paths that were specified, and the
error code message.
Additionally this patch refactors how errors are created, making it easier
to report them correctly.
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@337664 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
This patch implements directory_entry caching *almost* as specified in P0317r1. However, I explicitly chose to deviate from the standard as I'll explain below.
The approach I decided to take is a fully caching one. When `refresh()` is called, the cache is populated by calls to `stat` and `lstat` as needed.
During directory iteration the cache is only populated with the `file_type` as reported by `readdir`.
The cache can be in the following states:
* `_Empty`: There is nothing in the cache (likely due to an error)
* `_IterSymlink`: Created by directory iteration when we walk onto a symlink only the symlink file type is known.
* `_IterNonSymlink`: Created by directory iteration when we walk onto a non-symlink. Both the regular file type and symlink file type are known.
* `_RefreshSymlink` and `_RefreshNonSymlink`: A full cache created by `refresh()`. This case includes dead symlinks.
* `_RefreshSymlinkUnresolved`: A partial cache created by refresh when we fail to resolve the file pointed to by a symlink (likely due to permissions). Symlink attributes are cached, but attributes about the linked entity are not.
As mentioned, this implementation purposefully deviates from the standard. According to some readings of the specification, and the Windows filesystem implementation, the constructors and modifiers which don't pass an `error_code` must throw when the `directory_entry` points to a entity which doesn't exist. or when attribute resolution fails for another reason.
@BillyONeal has proposed a more reasonable set of requirements, where modifiers other than refresh ignore errors. This is the behavior libc++ currently implements, with the expectation some form of the new language will be accepted into the standard.
Some additional semantics which differ from the Windows implementation:
1. `refresh` will not throw when the entry doesn't exist. In this case we can still meet the functions specification, so we don't treat it as an error.
2. We don't clear the path name when a constructor fails via refresh (this will hopefully be changed in the standard as well).
It should be noted that libstdc++'s current implementation has the same behavior as libc++, except for point (2).
If the changes to the specification don't get accepted, we'll be able to make the changes later.
[1] http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0317r1.html
Reviewers: mclow.lists, gromer, ldionne, aaron.ballman
Subscribers: BillyONeal, christof, cfe-commits
Differential Revision: https://reviews.llvm.org/D49530
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@337516 91177308-0d34-0410-b5e6-96231b3b80d8
As I move towards implementing std::filesystem, there is a need to
make the existing tests run against both the std and experimental versions.
Additionally, it's helpful to allow running the tests against other
implementations of filesystem.
This patch converts the test to easily target either. First, it
adds a filesystem_include.hpp header which is soley responsible
for selecting and including the correct implementation. Second,
it converts existing tests to use this header instead of including
filesystem directly.
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@328475 91177308-0d34-0410-b5e6-96231b3b80d8
Add the completed std::experimental::filesystem implementation and tests.
The implementation supports C++11 or newer.
The TS is built as part of 'libc++experimental.a'. Users of the TS need to
manually link this library. Building and testing the TS can be disabled using
the CMake option '-DLIBCXX_ENABLE_FILESYSTEM=OFF'.
Currently 'libc++experimental.a' is not installed by default. To turn on the
installation of the library use '-DLIBCXX_INSTALL_EXPERIMENTAL_LIBRARY=ON'.
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@273034 91177308-0d34-0410-b5e6-96231b3b80d8
