Initial commit

.gitignore

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+.zig-cache/
+zig-out/

build.zig

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+const std = @import("std");
+
+// Although this function looks imperative, note that its job is to
+// declaratively construct a build graph that will be executed by an external
+// runner.
+pub fn build(b: *std.Build) void {
+    // Standard target options allows the person running `zig build` to choose
+    // what target to build for. Here we do not override the defaults, which
+    // means any target is allowed, and the default is native. Other options
+    // for restricting supported target set are available.
+    const target = b.standardTargetOptions(.{});
+
+    // Standard optimization options allow the person running `zig build` to select
+    // between Debug, ReleaseSafe, ReleaseFast, and ReleaseSmall. Here we do not
+    // set a preferred release mode, allowing the user to decide how to optimize.
+    const optimize = b.standardOptimizeOption(.{});
+
+    const exe = b.addExecutable(.{
+        .name = "checkKittyKeys",
+        .root_source_file = b.path("src/main.zig"),
+        .target = target,
+        .optimize = optimize,
+    });
+
+    // This declares intent for the executable to be installed into the
+    // standard location when the user invokes the "install" step (the default
+    // step when running `zig build`).
+    b.installArtifact(exe);
+
+    // This *creates* a Run step in the build graph, to be executed when another
+    // step is evaluated that depends on it. The next line below will establish
+    // such a dependency.
+    const run_cmd = b.addRunArtifact(exe);
+
+    // By making the run step depend on the install step, it will be run from the
+    // installation directory rather than directly from within the cache directory.
+    // This is not necessary, however, if the application depends on other installed
+    // files, this ensures they will be present and in the expected location.
+    run_cmd.step.dependOn(b.getInstallStep());
+
+    // This allows the user to pass arguments to the application in the build
+    // command itself, like this: `zig build run -- arg1 arg2 etc`
+    if (b.args) |args| {
+        run_cmd.addArgs(args);
+    }
+
+    // This creates a build step. It will be visible in the `zig build --help` menu,
+    // and can be selected like this: `zig build run`
+    // This will evaluate the `run` step rather than the default, which is "install".
+    const run_step = b.step("run", "Run the app");
+    run_step.dependOn(&run_cmd.step);
+
+    const exe_unit_tests = b.addTest(.{
+        .root_source_file = b.path("src/main.zig"),
+        .target = target,
+        .optimize = optimize,
+    });
+
+    const run_exe_unit_tests = b.addRunArtifact(exe_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_exe_unit_tests.step);
+}

build.zig.zon

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+.{
+    // This is the default name used by packages depending on this one. For
+    // example, when a user runs `zig fetch --save <url>`, this field is used
+    // as the key in the `dependencies` table. Although the user can choose a
+    // different name, most users will stick with this provided value.
+    //
+    // It is redundant to include "zig" in this name because it is already
+    // within the Zig package namespace.
+    .name = "checkKittyKeys",
+
+    // This is a [Semantic Version](https://semver.org/).
+    // In a future version of Zig it will be used for package deduplication.
+    .version = "0.0.0",
+
+    // This field is optional.
+    // This is currently advisory only; Zig does not yet do anything
+    // with this value.
+    //.minimum_zig_version = "0.11.0",
+
+    // This field is optional.
+    // Each dependency must either provide a `url` and `hash`, or a `path`.
+    // `zig build --fetch` can be used to fetch all dependencies of a package, recursively.
+    // Once all dependencies are fetched, `zig build` no longer requires
+    // internet connectivity.
+    .dependencies = .{
+        // See `zig fetch --save <url>` for a command-line interface for adding dependencies.
+        //.example = .{
+        //    // When updating this field to a new URL, be sure to delete the corresponding
+        //    // `hash`, otherwise you are communicating that you expect to find the old hash at
+        //    // the new URL.
+        //    .url = "https://example.com/foo.tar.gz",
+        //
+        //    // This is computed from the file contents of the directory of files that is
+        //    // obtained after fetching `url` and applying the inclusion rules given by
+        //    // `paths`.
+        //    //
+        //    // This field is the source of truth; packages do not come from a `url`; they
+        //    // come from a `hash`. `url` is just one of many possible mirrors for how to
+        //    // obtain a package matching this `hash`.
+        //    //
+        //    // Uses the [multihash](https://multiformats.io/multihash/) format.
+        //    .hash = "...",
+        //
+        //    // When this is provided, the package is found in a directory relative to the
+        //    // build root. In this case the package's hash is irrelevant and therefore not
+        //    // computed. This field and `url` are mutually exclusive.
+        //    .path = "foo",
+
+        //    // When this is set to `true`, a package is declared to be lazily
+        //    // fetched. This makes the dependency only get fetched if it is
+        //    // actually used.
+        //    .lazy = false,
+        //},
+    },
+
+    // Specifies the set of files and directories that are included in this package.
+    // Only files and directories listed here are included in the `hash` that
+    // is computed for this package. Only files listed here will remain on disk
+    // when using the zig package manager. As a rule of thumb, one should list
+    // files required for compilation plus any license(s).
+    // Paths are relative to the build root. Use the empty string (`""`) to refer to
+    // the build root itself.
+    // A directory listed here means that all files within, recursively, are included.
+    .paths = .{
+        "build.zig",
+        "build.zig.zon",
+        "src",
+        // For example...
+        //"LICENSE",
+        //"README.md",
+    },
+}

src/main.zig

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+const std = @import("std");
+const posix = std.posix;
+
+const MIN_RESPONSE_LEN = 5;
+const MAX_RESPONSE_LEN = 6;
+const MAX_READ_ATTEMPTS = 3;
+
+pub fn main() !void {
+    const stdin = std.io.getStdIn().reader();
+    const stdout_file = std.io.getStdOut().writer();
+    var bw = std.io.bufferedWriter(stdout_file);
+    const stdout = bw.writer();
+
+    const orig_termios = enterRawMode();
+    defer restoreTermios(orig_termios);
+
+    var seq: [MAX_RESPONSE_LEN]u8 = undefined;
+    var len: usize = 0;
+    var attempts: usize = 0;
+
+    try stdout.print("\x1b\x5b?u", .{});
+    try bw.flush();
+
+    while (len < MAX_RESPONSE_LEN) {
+        seq[len] = stdin.readByte() catch {
+            if (len != 0) break;
+
+            attempts += 1;
+            if (attempts == MAX_READ_ATTEMPTS) break;
+
+            continue;
+        };
+
+        len += 1;
+    }
+
+    var valid_response = len >= MIN_RESPONSE_LEN;
+
+    if (valid_response) {
+        valid_response = valid_response and seq[0] == '\x1b';
+        valid_response = valid_response and seq[1] == '\x5b';
+        valid_response = valid_response and seq[2] == '?';
+        valid_response = valid_response and seq[len - 1] == 'u';
+        const flags = std.fmt.parseInt(u8, seq[3 .. len - 1], 10) catch blk: {
+            valid_response = false;
+            break :blk 0;
+        };
+
+        valid_response = valid_response and flags < 32;
+    }
+
+    if (len != 0 and valid_response) {
+        try stdout.print("The kitty keyboard protocol is supported\r\n", .{});
+    } else if (len != 0) {
+        try stdout.print("Got an unexpected response. I'm not sure what that means\r\n", .{});
+    } else {
+        try stdout.print("The kitty keyboard protocol is not supported\r\n", .{});
+    }
+
+    try bw.flush();
+}
+
+fn enterRawMode() std.posix.termios {
+    const tty_handle = std.io.getStdIn().handle;
+    const orig_termios = posix.tcgetattr(tty_handle) catch unreachable;
+
+    var raw = orig_termios;
+    raw.iflag.BRKINT = false;
+    raw.iflag.ICRNL = false;
+    raw.iflag.INPCK = false;
+    raw.iflag.ISTRIP = false;
+    raw.iflag.IXON = false;
+
+    raw.oflag.OPOST = false;
+
+    raw.cflag.CSIZE = posix.CSIZE.CS8;
+
+    raw.lflag.ECHO = false;
+    raw.lflag.ICANON = false;
+    raw.lflag.IEXTEN = false;
+    raw.lflag.ISIG = false;
+
+    raw.cc[@intFromEnum(posix.V.MIN)] = 0;
+    raw.cc[@intFromEnum(posix.V.TIME)] = 1;
+
+    posix.tcsetattr(tty_handle, posix.TCSA.FLUSH, raw) catch unreachable;
+
+    return orig_termios;
+}
+
+fn restoreTermios(orig_termios: std.posix.termios) void {
+    posix.tcsetattr(std.io.getStdIn().handle, posix.TCSA.FLUSH, orig_termios) catch unreachable;
+}