stdx.zig

//! Extensions to the standard library -- things which could have been in std, but aren't.

const std = @import("std");

// std.SemanticVersion requires there be no extra characters after the
// major/minor/patch numbers. But when we try to parse `uname
// --kernel-release` (note: while Linux doesn't follow semantic
// versioning, it doesn't violate it either), some distributions have
// extra characters, such as this Fedora one: 6.3.8-100.fc37.x86_64, and
// this WSL one has more than three dots:
// 5.15.90.1-microsoft-standard-WSL2.
pub fn parse_dirty_semver(dirty_release: []const u8) !std.SemanticVersion {
    const release = blk: {
        var last_valid_version_character_index: usize = 0;
        var dots_found: u8 = 0;
        for (dirty_release) |c| {
            if (c == '.') dots_found += 1;
            if (dots_found == 3) {
                break;
            }

            if (c == '.' or (c >= '0' and c <= '9')) {
                last_valid_version_character_index += 1;
                continue;
            }

            break;
        }

        break :blk dirty_release[0..last_valid_version_character_index];
    };

    return std.SemanticVersion.parse(release);
}

test "stdx.zig: parse_dirty_semver" {
    const SemverTestCase = struct {
        dirty_release: []const u8,
        expected_version: std.SemanticVersion,
    };

    const cases = &[_]SemverTestCase{
        .{
            .dirty_release = "1.2.3",
            .expected_version = std.SemanticVersion{ .major = 1, .minor = 2, .patch = 3 },
        },
        .{
            .dirty_release = "1001.843.909",
            .expected_version = std.SemanticVersion{ .major = 1001, .minor = 843, .patch = 909 },
        },
        .{
            .dirty_release = "6.3.8-100.fc37.x86_64",
            .expected_version = std.SemanticVersion{ .major = 6, .minor = 3, .patch = 8 },
        },
        .{
            .dirty_release = "5.15.90.1-microsoft-standard-WSL2",
            .expected_version = std.SemanticVersion{ .major = 5, .minor = 15, .patch = 90 },
        },
    };
    for (cases) |case| {
        const version = try parse_dirty_semver(case.dirty_release);
        try std.testing.expectEqual(case.expected_version, version);
    }
}