build.zig

const std = @import("std");

pub const min_zig_version = std.SemanticVersion{ .major = 0, .minor = 12, .patch = 0 };

pub fn build(b: *std.Build) void {
    ensureZigVersion() catch return;
    const target = b.standardTargetOptions(.{});
    const optimize = b.standardOptimizeOption(.{});

    const lib = b.addSharedLibrary(.{
        .name = "zsmooth",
        .root_source_file = .{ .path = "src/zsmooth.zig" },
        .target = target,
        .optimize = optimize,

        // Improve build times by giving an upper bound to memory,
        // thus enabling multi-threaded builds.
        .max_rss = 1024 * 1024 * 1024 * 2, // 2GB

        // This application is single threaded (as VapourSynth handles the threading for us)
        // so might as well mark it so in case we ever import data
        // structures that *might* have thread safety built in,
        // in which case setting this value will optimize out any threading
        // or locking constructs.
        .single_threaded = true,
    });

    const vapoursynth_dep = b.dependency("vapoursynth", .{
        .target = target,
        .optimize = optimize,
    });

    lib.root_module.addImport("vapoursynth", vapoursynth_dep.module("vapoursynth"));
    lib.linkLibC(); // Necessary to use the C memory allocator.

    if (lib.root_module.optimize == .ReleaseFast) {
        lib.root_module.strip = true;
    }

    b.installArtifact(lib);

    // Test setup
    // Creates a step for unit testing. This only builds the test executable
    // but does not run it.
    const lib_unit_tests = b.addTest(.{
        .root_source_file = .{ .path = "src/zsmooth.zig" },
        .target = target,
        .optimize = optimize,
    });
    lib_unit_tests.root_module.addImport("vapoursynth", vapoursynth_dep.module("vapoursynth"));
    lib_unit_tests.linkLibC();

    const run_lib_unit_tests = b.addRunArtifact(lib_unit_tests);

    // Similar to creating the run step earlier, this exposes a `test` step to
    // the `zig build --help` menu, providing a way for the user to request
    // running the unit tests.
    const test_step = b.step("test", "Run unit tests");
    test_step.dependOn(&run_lib_unit_tests.step);
}

fn ensureZigVersion() !void {
    var installed_ver = @import("builtin").zig_version;
    installed_ver.build = null;

    if (installed_ver.order(min_zig_version) == .lt) {
        std.log.err("\n" ++
            \\---------------------------------------------------------------------------
            \\
            \\Installed Zig compiler version is too old.
            \\
            \\Min. required version: {any}
            \\Installed version: {any}
            \\
            \\Please install newer version and try again.
            \\Latest version can be found here: https://ziglang.org/download/
            \\
            \\---------------------------------------------------------------------------
            \\
        , .{ min_zig_version, installed_ver });
        return error.ZigIsTooOld;
    }
}