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Asynchronous directory creation and open after an optional precondition.
Note that if there is already a handle open to the directory requested,
that will be returned instead of a new handle unless file_flags::unique_directory_handle
is specified. For such handles where available_to_directory_cache() is
true, they cannot be explicitly closed either, you must let the reference
count reach zero for that to happen. Related types:
Be aware that on Windows AFIO operates exclusively in the NT kernel namespace,
NOT the Win32 namespace, and therefore paths you supply are converted
by path_req
in NT kernel namespace
paths. afio::path
can convert an afio path
back to a Filesystem TS path for you, but note that this may not be the
path that was supplied originally. NT kernel namespace paths have a 32,767
character limit and an almost POSIX like lack of restrictions on naming
or historical behaviour quirks, but as a result AFIO does not support
DOS short names or any of the other historical Win32 filing system baggage.
normalise_path()
template<class T, typename> future async_dir(T _path, file_flags _flags = file_flags::none)
Type |
Concept |
Name |
Description |
---|---|---|---|
class T |
The type of path to be used. |
- |
Must be specified |
- |
Must be specified |
||
T |
_path |
The filing system path to be used. |
|
file_flags |
_flags |
The flags to be used. |
A future<void>
#include <boost/afio/v2/afio.hpp>
Operating system | Race guarantees under a changing file system |
---|---|
FreeBSD, Linux, OS X, Windows | No guarantees. |
Amortised O(1) to dispatch. Amortised O(1) to complete if directory creation is constant time.
Propagates the exception of any input precondition with an errored state
at the point of dispatch, and throws a std::invalid_argument
if any inputs have values which could not possibly be correct. Note that
error code returning functions may still throw exceptions e.g. failure
to allocate memory.
using namespace BOOST_AFIO_V2_NAMESPACE; using BOOST_AFIO_V2_NAMESPACE::rmdir; std::shared_ptr<boost::afio::dispatcher> dispatcher = boost::afio::make_dispatcher().get(); current_dispatcher_guard h(dispatcher); // Free function try { // Schedule creating a directory called testdir auto mkdir(async_dir("testdir", boost::afio::file_flags::create)); // Schedule creating a file called testfile in testdir only when testdir has been // created auto mkfile(async_file(mkdir, "testfile", boost::afio::file_flags::create)); // Schedule creating a symbolic link called linktodir to the item referred to by // the precondition // i.e. testdir. Note that on Windows you can only symbolic link directories. auto mklink( async_symlink(mkdir, "linktodir", mkdir, boost::afio::file_flags::create)); // Schedule deleting the symbolic link only after when it has been created auto rmlink(async_rmsymlink(mklink)); // Schedule deleting the file only after when it has been created auto rmfile(async_close(async_rmfile(mkfile))); // Schedule waiting until both the preceding operations have finished auto barrier(dispatcher->barrier({rmlink, rmfile})); // Schedule deleting the directory only after the barrier completes auto rmdir(async_rmdir(depends(barrier.front(), mkdir))); // Check ops for errors boost::afio::when_all_p(mkdir, mkfile, mklink, rmlink, rmfile, rmdir).wait(); } catch(...) { std::cerr << boost::current_exception_diagnostic_information(true) << std::endl; throw; } // Batch try { // Schedule creating a directory called testdir auto mkdir( dispatcher->dir(std::vector<boost::afio::path_req>( 1, boost::afio::path_req( "testdir", boost::afio::file_flags::create))).front()); // Schedule creating a file called testfile in testdir only when testdir has been // created auto mkfile(dispatcher->file(std::vector<boost::afio::path_req>( 1, boost::afio::path_req::relative( mkdir, "testfile", boost::afio::file_flags::create))).front()); // Schedule creating a symbolic link called linktodir to the item referred to by // the precondition // i.e. testdir. Note that on Windows you can only symbolic link directories. // Note that creating // symlinks must *always* be as an absolute path, as that is how they are stored. auto mklink(dispatcher->symlink(std::vector<boost::afio::path_req>( 1, boost::afio::path_req::absolute( mkdir, "testdir/linktodir", boost::afio::file_flags::create))).front()); // Schedule deleting the symbolic link only after when it has been created auto rmlink(dispatcher->close(std::vector<future<>>( 1, dispatcher->rmsymlink(mklink))).front()); // Schedule deleting the file only after when it has been created auto rmfile( dispatcher->close(std::vector<future<>>(1, dispatcher->rmfile(mkfile))).front()); // Schedule waiting until both the preceding operations have finished auto barrier(dispatcher->barrier({rmlink, rmfile})); // Schedule deleting the directory only after the barrier completes auto rmdir( dispatcher->rmdir(std::vector<path_req>( 1, dispatcher->depends(barrier.front(), mkdir))).front()); // Check ops for errors boost::afio::when_all_p(mkdir, mkfile, mklink, rmlink, rmfile, rmdir).wait(); } catch(...) { std::cerr << boost::current_exception_diagnostic_information(true) << std::endl; throw; }