libcruft-vk/icd/vendor_posix.cpp

#include "vendor.hpp"

#include <cruft/util/log.hpp>
#include <cruft/util/posix/except.hpp>

#include <cruft/json/tree.hpp>

#include <wordexp.h>

namespace fs = std::experimental::filesystem;


///////////////////////////////////////////////////////////////////////////////
std::vector<cruft::vk::icd::icd_t>
cruft::vk::icd::enumerate (void)
{
    // The predefined, ordered, search locations for manifests
    static char const *locations[] = {
        "/usr/local/etc/vulkan/icd.d/",
        "/usr/local/share/vulkan/icd.d/",
        "/etc/vulkan/icd.d/",
        "/usr/share/vulkan/icd.d/",
        "$HOME/.local/share/vulkan/icd.d/",
    };

    std::vector<icd_t> found;

    for (auto const &loc: locations) {
        // We use wordexp rather than std::filesystem because we need to
        // perform environment expansion to account of $HOME in at least one
        // of the paths, so we may as well just use the same approach for
        // everything else too.
        wordexp_t words;
        posix::error::try_call (wordexp, loc, &words, WRDE_NOCMD | WRDE_UNDEF);
        std::unique_ptr<wordexp_t, decltype(&wordfree)> cleanup {&words, &wordfree};

        // Just try to parse everything we can find in the directory (if it
        // happens to exist) and fail out if it doesn't work. Marginally safer
        // than doing various tests.
        for (size_t i = 0; i < words.we_wordc; ++i) {
            try {
                for (auto const &path: fs::directory_iterator (words.we_wordv[i])) {
                    found.push_back (from_json<icd_t> (*json::tree::parse (path)));
                }
            } catch (std::exception const &e) {
                LOG_INFO("failed to parse icd manifest; %!", e.what ());
            }
        }
    }

    return found;
}