Clircle provides a cross-platform API to detect read / write cycles from your user-supplied arguments. You can get the important identifiers of a file (from a path) and for all three stdio streams, if they are piped from or to a file as well.
Imagine you want to read data from a couple of files and output something according to the contents of these files. If the user redirects the output of your program to one of the input files, you might end up in an infinite circle of reading and writing.
The crate provides the struct Identifier
which is a platform dependent type alias, so that
you can use it on all platforms and do not need to introduce any conditional compilation
yourself.
On both Unix and Windows systems, Identifier
holds information to identify a file on a disk.
The Clircle
trait is implemented on both of these structs and requires TryFrom
for the
clircle::Stdio
enum and for &Path
, so that all possible inputs can be represented as an
Identifier
.
Finally, Clircle
is a subtrait of Eq
, so that the identifiers can be conveniently compared
and circles can be detected.
The clircle
crate also provides some convenience functions around the comparison of Clircle
implementors.
The clircle
crate seamlessly works on Linux and Windows through
a single API, so no conditional compilation is needed at all.
Furthermore, MetadataExt
is not stable on Windows yet, meaning you
would have to dig into the Windows APIs yourself to get the information
needed to identify a file.
This crate originated in a pull request to the bat
project.
The bat
tool strives to be a drop-in replacement for the unix tool cat
.
Since cat
detects these cycles, bat
has to do so too, which is where most
of this code came into play. However, it was decided, that the new logic was
- useful for other projects and
- too platform specific for
bat
s scope.
So now, you can use clircle
too!