wayland-de: Show current task in waybar

Changes

8 changed files (+405/-3)

• README.md
  • @@ -58,6 +58,9 @@ - [niri](https://github.com/YaLTeR/niri)
    - [`pantheon-polkit-agent`](https://archlinux.org/packages/extra/x86_64/pantheon-polkit-agent/) ... The one installed installed using Nix cannot lookup `polkit-agent-helper-1`. - [swaylock](https://github.com/swaywm/swaylock) ... access to PAM required, which is not possible with regular user Nix installation. + A custom Swaybar module assumes Markdown file placed at `$XDG_DATA_HOME/todo.md`. + Create a symbolic link or normal file there (module tries to read in 10s interval if the file does not exist.) + ## Programs ### `hm-clean`
• features/wayland-de/waybar.nix
  • @@ -14,8 +14,13 @@ #
    # SPDX-License-Identifier: 0BSD { config, lib, pkgs, ... }: { - programs = - lib.mkIf config.features.wayland-de.enable { + config = lib.mkIf config.features.wayland-de.enable { + home.packages = [ + # /programs/waybar-text + pkgs.my-waybar-text + ]; + + programs = { waybar = { enable = true;
  • @@ -23,7 +28,7 @@ settings = {
    main = { layer = "top"; - modules-left = [ ]; + modules-left = [ "custom/todo" ]; modules-right = [ "clock" "pulseaudio" "tray" ]; clock = {
  • @@ -39,9 +44,16 @@ format-muted = "muted {format_source}";
    on-click = "pavucontrol"; }; + + "custom/todo" = { + exec = "${pkgs.my-waybar-text}/bin/,waybar-text --trim-md-list ${config.xdg.dataHome}/todo.md"; + restart-interval = 10; + return-type = "json"; + }; }; }; }; }; + }; }
• flake.nix
  • @@ -68,6 +68,7 @@ (import ./overlays/legit.nix)
    # Local packages (final: prev: { my-theme = prev.callPackage ./programs/theme { }; + my-waybar-text = prev.callPackage ./programs/waybar-text { }; }) ]; };
• programs/waybar-text/build.zig (new)
  • @@ -0,0 +1,43 @@
    + // Copyright 2025 Shota FUJI <pockawoooh@gmail.com> + // + // Licensed under the Apache License, Version 2.0 (the "License"); + // you may not use this file except in compliance with the License. + // You may obtain a copy of the License at + // + // http://www.apache.org/licenses/LICENSE-2.0 + // + // Unless required by applicable law or agreed to in writing, software + // distributed under the License is distributed on an "AS IS" BASIS, + // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + // See the License for the specific language governing permissions and + // limitations under the License. + // + // SPDX-License-Identifier: Apache-2.0 + + const std = @import("std"); + + pub fn build(b: *std.Build) !void { + const target = b.standardTargetOptions(.{}); + const optimize = b.standardOptimizeOption(.{}); + + const exe = b.addExecutable(.{ + .name = ",waybar-text", + .root_source_file = b.path("src/main.zig"), + .target = target, + .optimize = optimize, + }); + + b.installArtifact(exe); + + // zig build run + { + const step = b.step("run", "Compile and run program"); + + const run = b.addRunArtifact(exe); + if (b.args) |args| { + run.addArgs(args); + } + + step.dependOn(&run.step); + } + }
• programs/waybar-text/default.nix (new)
  • @@ -0,0 +1,31 @@
    + # Copyright 2025 Shota FUJI <pockawoooh@gmail.com> + # + # Licensed under the Apache License, Version 2.0 (the "License"); + # you may not use this file except in compliance with the License. + # You may obtain a copy of the License at + # + # http://www.apache.org/licenses/LICENSE-2.0 + # + # Unless required by applicable law or agreed to in writing, software + # distributed under the License is distributed on an "AS IS" BASIS, + # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + # See the License for the specific language governing permissions and + # limitations under the License. + # + # SPDX-License-Identifier: Apache-2.0 + + { stdenvNoCC, zig }: + stdenvNoCC.mkDerivation rec { + pname = "my-waybar-text"; + version = "1.0.0"; + + nativeBuildInputs = [ zig.hook ]; + + src = ./.; + + meta = { + mainProgram = ",waybar-text"; + }; + + dontConfigure = true; + }
• programs/waybar-text/src/Options.zig (new)
  • @@ -0,0 +1,114 @@
    + // Copyright 2025 Shota FUJI <pockawoooh@gmail.com> + // + // Licensed under the Apache License, Version 2.0 (the "License"); + // you may not use this file except in compliance with the License. + // You may obtain a copy of the License at + // + // http://www.apache.org/licenses/LICENSE-2.0 + // + // Unless required by applicable law or agreed to in writing, software + // distributed under the License is distributed on an "AS IS" BASIS, + // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + // See the License for the specific language governing permissions and + // limitations under the License. + // + // SPDX-License-Identifier: Apache-2.0 + + const std = @import("std"); + + allocator: std.mem.Allocator, + file_path: []const u8, + class: ?[]const u8 = null, + trim_markdown_list_prefix: bool = false, + + pub const InitError = error{ + IncorrectUsage, + ShowHelp, + } || std.mem.Allocator.Error || std.fs.Dir.RealPathAllocError; + + const class_arg_prefix = "--class="; + + pub const helpText = + \\,waybar-text - Watches text file and print its first line + \\ + \\[USAGE] + \\,waybar-text [--class=string] <FILE> + \\ + \\[OPTIONS] + \\--help Print this message to stdout and exits. + \\--class=string Set CSS class for the output text. + \\--trim-md-list Trim markdown list prefixes from displaying text. + \\ + ; + + pub fn init(allocator: std.mem.Allocator) InitError!@This() { + var iter = try std.process.ArgIterator.initWithAllocator(allocator); + defer iter.deinit(); + + // Skip program name. + _ = iter.next(); + + var first_positional_arg: ?[]const u8 = null; + + var class: ?[]const u8 = null; + errdefer if (class) |slice| allocator.free(slice); + + var trim_markdown_list_prefix: bool = false; + + while (iter.next()) |arg| { + if (std.mem.eql(u8, arg, "--help")) { + return InitError.ShowHelp; + } + + if (std.mem.startsWith(u8, arg, class_arg_prefix)) { + if (class) |_| { + std.log.err("--class can't be used more than once", .{}); + return InitError.IncorrectUsage; + } + + class = try allocator.dupe(u8, arg[class_arg_prefix.len..]); + if (class) |c| if (c.len == 0) { + std.log.err("--class requires a value", .{}); + return InitError.IncorrectUsage; + }; + + continue; + } + + if (std.mem.eql(u8, arg, "--trim-md-list")) { + trim_markdown_list_prefix = true; + continue; + } + + if (std.mem.startsWith(u8, arg, "-")) { + std.log.err("Unknown option: {s}", .{arg}); + return InitError.IncorrectUsage; + } + + if (first_positional_arg) |_| { + std.log.err("FILE can't be used more than once", .{}); + return InitError.IncorrectUsage; + } + + first_positional_arg = arg; + } + + const cwd = std.fs.cwd(); + + const file = try cwd.realpathAlloc(allocator, first_positional_arg orelse { + std.log.err("FILE is required", .{}); + return InitError.IncorrectUsage; + }); + + return .{ + .allocator = allocator, + .file_path = file, + .class = class, + .trim_markdown_list_prefix = trim_markdown_list_prefix, + }; + } + + pub fn deinit(self: *const @This()) void { + self.allocator.free(self.file_path); + if (self.class) |class| self.allocator.free(class); + }
• programs/waybar-text/src/main.zig (new)
  • @@ -0,0 +1,160 @@
    + // Copyright 2025 Shota FUJI <pockawoooh@gmail.com> + // + // Licensed under the Apache License, Version 2.0 (the "License"); + // you may not use this file except in compliance with the License. + // You may obtain a copy of the License at + // + // http://www.apache.org/licenses/LICENSE-2.0 + // + // Unless required by applicable law or agreed to in writing, software + // distributed under the License is distributed on an "AS IS" BASIS, + // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + // See the License for the specific language governing permissions and + // limitations under the License. + // + // SPDX-License-Identifier: Apache-2.0 + + //! Watches specified file and print its first line in waybar output JSON. + + const std = @import("std"); + + const Options = @import("./Options.zig"); + const waybar = @import("./waybar.zig"); + + const ExitCode = enum(u8) { + ok = 0, + unknown_error = 1, + incorrect_usage = 2, + read_permission_error = 3, + file_watch_error = 4, + out_of_memory = 5, + file_not_found = 6, + + pub fn to_u8(self: @This()) u8 { + return @intFromEnum(self); + } + }; + + pub fn main() !u8 { + var arena = std.heap.ArenaAllocator.init(std.heap.page_allocator); + defer arena.deinit(); + + const allocator = arena.allocator(); + + const options = Options.init(allocator) catch |err| switch (err) { + error.IncorrectUsage => { + try std.io.getStdErr().writeAll(Options.helpText); + return ExitCode.incorrect_usage.to_u8(); + }, + error.ShowHelp => { + try std.io.getStdOut().writeAll(Options.helpText); + return ExitCode.ok.to_u8(); + }, + error.OutOfMemory => { + std.log.err("Out of memory", .{}); + return ExitCode.out_of_memory.to_u8(); + }, + error.FileNotFound => { + std.log.err("File not found", .{}); + return ExitCode.file_not_found.to_u8(); + }, + else => { + std.log.err("Unexpected error: {s}", .{@errorName(err)}); + return ExitCode.unknown_error.to_u8(); + }, + }; + defer options.deinit(); + + print(allocator, &options) catch |err| switch (err) { + error.OutOfMemory => { + std.log.err("Out of memory", .{}); + return ExitCode.out_of_memory.to_u8(); + }, + else => { + std.log.err("Unexpected error: {s}", .{@errorName(err)}); + return ExitCode.unknown_error.to_u8(); + }, + }; + + watch(allocator, &options) catch |err| switch (err) { + error.FileNotFound => { + std.log.err("File not found", .{}); + return ExitCode.file_not_found.to_u8(); + }, + else => { + std.log.err("Unexpected error: {s}", .{@errorName(err)}); + return ExitCode.unknown_error.to_u8(); + }, + }; + + return ExitCode.ok.to_u8(); + } + + fn print(allocator: std.mem.Allocator, opts: *const Options) !void { + const file = try std.fs.openFileAbsolute(opts.file_path, .{}); + defer file.close(); + + const line = try file.reader().readUntilDelimiterAlloc(allocator, '\n', std.math.maxInt(usize)); + defer allocator.free(line); + + const line_trimmed: []const u8 = if (opts.trim_markdown_list_prefix) line_start: { + if (line.len < 2) { + break :line_start line; + } + + break :line_start switch (line[0]) { + '*', '-', '+' => line[(std.mem.indexOfNonePos(u8, line, 1, " \t") orelse 0)..], + else => line, + }; + } else line; + + const output = waybar.ModuleOutput{ + .text = line_trimmed, + .tooltip = line_trimmed, + .class = opts.class, + }; + + const buffer = try allocator.alloc(u8, output.getEncodedSize() + 1); + defer allocator.free(buffer); + + var fbs = std.io.fixedBufferStream(buffer); + const writer = fbs.writer(); + try output.encode(writer); + try writer.writeByte('\n'); + + try std.io.getStdOut().writeAll(buffer); + } + + const watch_flags = std.os.linux.IN.MODIFY | std.os.linux.IN.DELETE_SELF; + + fn watch(allocator: std.mem.Allocator, opts: *const Options) !void { + const fd = try std.posix.inotify_init1(0); + defer std.posix.close(fd); + + var wd = try std.posix.inotify_add_watch(fd, opts.file_path, watch_flags); + defer std.posix.inotify_rm_watch(fd, wd); + + var buffer: [64]std.os.linux.inotify_event = undefined; + while (true) { + const read_bytes = try std.posix.read(fd, std.mem.sliceAsBytes(&buffer)); + + var i: usize = 0; + while (i < read_bytes) : (i += buffer[i].len + @sizeOf(std.os.linux.inotify_event)) { + const event = buffer[i]; + + // Certain text editors (I mean, vim/neovim) creates a new file and remove the old one + // instead of writing to the file. We have to watch the new file otherwise no events + // will be fired for the path anymore. + if (event.mask & std.os.linux.IN.DELETE_SELF != 0) { + wd = try std.posix.inotify_add_watch(fd, opts.file_path, watch_flags); + continue; + } + + if (event.mask & std.os.linux.IN.MODIFY != 0) { + print(allocator, opts) catch |err| { + std.log.warn("Unable to print: {s}", .{@errorName(err)}); + }; + } + } + } + }
• programs/waybar-text/src/waybar.zig (new)
  • @@ -0,0 +1,38 @@
    + // Copyright 2025 Shota FUJI <pockawoooh@gmail.com> + // + // Licensed under the Apache License, Version 2.0 (the "License"); + // you may not use this file except in compliance with the License. + // You may obtain a copy of the License at + // + // http://www.apache.org/licenses/LICENSE-2.0 + // + // Unless required by applicable law or agreed to in writing, software + // distributed under the License is distributed on an "AS IS" BASIS, + // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + // See the License for the specific language governing permissions and + // limitations under the License. + // + // SPDX-License-Identifier: Apache-2.0 + + const std = @import("std"); + + pub const ModuleOutput = struct { + text: []const u8, + tooltip: ?[]const u8 = null, + class: ?[]const u8 = null, + + const jsonStringifyOptions = std.json.StringifyOptions{ + .emit_null_optional_fields = false, + .whitespace = .minified, + }; + + pub fn getEncodedSize(self: *const @This()) usize { + var cw = std.io.countingWriter(std.io.null_writer); + std.json.stringify(self, jsonStringifyOptions, cw.writer()) catch return 0; + return cw.bytes_written; + } + + pub fn encode(self: *const @This(), writer: anytype) @TypeOf(writer).Error!void { + try std.json.stringify(self, jsonStringifyOptions, writer); + } + };