nix-super/src/libutil/executable-path.hh
John Ericson a97a08411c More support for std::filepath in libnixutil
We're not replacing `Path` in exposed definitions in many cases, but
just adding alternatives. This will allow us to "top down" change `Path`
to `std::fileysystem::path`, and then we can remove the `Path`-using
utilities which will become unused.

Also add some test files which we forgot to include in the libutil unit
tests `meson.build`.

Co-Authored-By: siddhantCodes <siddhantk232@gmail.com>
2024-08-26 17:23:56 -04:00

81 lines
2.3 KiB
C++

#pragma once
///@file
#include "file-system.hh"
namespace nix {
MakeError(ExecutableLookupError, Error);
/**
* @todo rename, it is not just good for execuatable paths, but also
* other lists of paths.
*/
struct ExecutablePath
{
std::vector<std::filesystem::path> directories;
constexpr static const OsChar separator =
#ifdef WIN32
L';'
#else
':'
#endif
;
/**
* Parse `path` into a list of paths.
*
* On Unix we split on `:`, on Windows we split on `;`.
*
* For Unix, this is according to the POSIX spec for `PATH`.
* https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap08.html#tag_08_03
*/
static ExecutablePath parse(const OsString & path);
/**
* Load the `PATH` environment variable and `parse` it.
*/
static ExecutablePath load();
/**
* Opposite of `parse`
*/
OsString render() const;
/**
* Search for an executable.
*
* For Unix, this is according to the POSIX spec for `PATH`.
* https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap08.html#tag_08_03
*
* @param exe This must just be a name, and not contain any `/` (or
* `\` on Windows). in case it does, per the spec no lookup should
* be perfomed, and the path (it is not just a file name) as is.
* This is the caller's respsonsibility.
*
* This is a pure function, except for the default `isExecutable`
* argument, which uses the ambient file system to check if a file is
* executable (and exists).
*
* @return path to a resolved executable
*/
std::optional<std::filesystem::path> findName(
const OsString & exe,
std::function<bool(const std::filesystem::path &)> isExecutableFile = isExecutableFileAmbient) const;
/**
* Like the `findName` but also allows a file path as input.
*
* This implements the full POSIX spec: if the path is just a name,
* it searches like the above. Otherwise, it returns the path as is.
* If (in the name case) the search fails, an exception is thrown.
*/
std::filesystem::path findPath(
const std::filesystem::path & exe,
std::function<bool(const std::filesystem::path &)> isExecutable = isExecutableFileAmbient) const;
bool operator==(const ExecutablePath &) const = default;
};
} // namespace nix