add attwm support

CLAUDE.md

@@ -104,6 +104,30 @@ the QML side parses those lines into `tempPath`/`batPath`, which then feed
   to pick up layer-surface fixes ahead of release.
 - Native Quickshell services back some modules: `Quickshell.I3` (workspaces),
   `Quickshell.Services.SystemTray` (tray), PipeWire (volume).
+- **Window manager backends are picked by `config/Compositor.qml`**, a singleton
+  that reads *only* environment variables — Hyprland's instance signature,
+  `$SWAYSOCK`/`$I3SOCK`, else attwm as the fallback (it announces nothing of its
+  own, being a river client rather than a compositor). **Never let the detector
+  do IPC**, and **never read a backend singleton outside its guard**: touching
+  `Attwm.x` / `I3.x` / `Hyprland.x` instantiates it, and an idle backend sits
+  there retrying a socket that will never answer. Every use is behind
+  `Compositor.isAttwm && …` or a `?:` whose untaken branch is never evaluated —
+  that short-circuit *is* the mechanism. It's verifiable: under attwm the log
+  has no `$I3SOCK is unset` line, under Sway it does.
+- **attwm** (`services/Attwm.qml`, adapted from the reference client in that
+  repo — keep the two in step) is one `Socket` doing both directions: it
+  `subscribe`s for a JSON state object per change and writes `attwmctl`-grammar
+  commands back down the same connection, so a click costs no process spawn.
+  Its model is dwm's, not i3's — nine fixed tags addressed by *bitmask*
+  (`tags`/`occupied`), several viewable at once, per output, and no urgency
+  (the protocol has no attention-request event). `tagCount` deliberately
+  defaults to 0, not 9, so a wrong detection guess renders nothing instead of a
+  row of dead tags. `state` is left stale on disconnect so an attwm restart
+  freezes the bar rather than blanking it.
+- Every backend renders through **`widgets/WorkspaceChip.qml`**, whose `dimmed`
+  and `dot` are presentational rather than semantic — "empty" means different
+  things per backend (i3 only lists workspaces that exist; attwm always
+  publishes all nine tags), so the call site decides.
 - **Making a module interactive (popups/drawers):** wrap the module's `Pill` in
   an `Item` (forward `implicitWidth`/`implicitHeight` from the pill so the bar's
   RowLayout still sizes it), add a `MouseArea`, and open a `Quickshell.PopupWindow`;

README.md

@@ -1,6 +1,8 @@
 # quickshell-bar
 
-A Wayland status bar for [Sway](https://swaywm.org/), built with
+A Wayland status bar for [Sway](https://swaywm.org/), i3,
+[Hyprland](https://hypr.land/) and attwm (a dwm-like window manager for
+[river](https://codeberg.org/river/river)), built with
 [Quickshell](https://quickshell.outfoxxed.me/) and packaged with Nix flakes.
 
 ![bar](docs/bar.png)
@@ -11,7 +13,8 @@ Left → right:
 
 | Module      | Source                                   |
 |-------------|------------------------------------------|
-| Workspaces  | Sway/i3 IPC (`Quickshell.I3`)            |
+| Workspaces  | Sway/i3 IPC (`Quickshell.I3`), Hyprland IPC, or attwm tags |
+| Layout      | attwm only — layout symbol, click to cycle |
 | Clock       | local time (center)                      |
 | CPU         | `/proc/stat` (per-core load bars + overall %) |
 | CPU temp    | `coretemp`/`k10temp` hwmon, else thermal |
@@ -33,7 +36,12 @@ use native Quickshell services.
 
 ## Requirements
 
-- Sway (or i3) — the workspace module talks to `$SWAYSOCK`/`$I3SOCK`.
+- A supported window manager, detected from the environment at startup:
+  Sway/i3 (`$SWAYSOCK`/`$I3SOCK`), Hyprland
+  (`$HYPRLAND_INSTANCE_SIGNATURE`), or attwm — assumed when neither of the
+  other two announces itself, and talking to
+  `$XDG_RUNTIME_DIR/attwm-$WAYLAND_DISPLAY.sock` (override with
+  `$ATTWM_SOCKET`).
 - A running PipeWire session for the volume module.
 - Nix with flakes enabled (`experimental-features = nix-command flakes`).
 
@@ -74,6 +82,23 @@ Or, if you install the package (e.g. into your system/Home-Manager profile),
 just `exec quickshell-bar`. The bar anchors to the top edge and reserves an
 exclusive zone, so windows tile beneath it automatically.
 
+## Use it from attwm
+
+attwm is started by river, so launch the bar from river's init alongside it:
+
+```sh
+#!/bin/sh
+# ~/.config/river/init
+quickshell-bar &
+exec attwm
+```
+
+Tags replace workspaces: all nine are always shown, dim when empty, underlined
+when they hold windows you aren't looking at. Left click views a tag, right
+click toggles it into the view, middle click sends the focused window there.
+The layout symbol sits to their right — click to cycle forward, right click
+back. A bar can only map at all because attwm binds `river_layer_shell_v1`.
+
 ## Configuration
 
 Everything is plain QML — edit and the bar hot-reloads.
@@ -91,13 +116,16 @@ shell.qml              entry point — one Bar per monitor
 config/
   Theme.qml            colours, sizes, fonts (singleton)
   Icons.qml            Nerd Font glyphs (singleton)
+  Compositor.qml       which window manager are we under? env only (singleton)
 services/
   SysStats.qml         reads /proc & /sys via FileView into reactive props (singleton)
+  Attwm.qml            attwm IPC socket: state in, commands out (singleton)
   discover.sh          one-shot hwmon/battery path discovery at startup
 widgets/
   Bar.qml              the PanelWindow + layout
   Pill.qml             rounded container used by every module
   MetricPill.qml       icon + value helper
-  Workspaces.qml  Clock.qml  CpuGraph.qml  CpuTemp.qml
+  WorkspaceChip.qml    one workspace/tag chip, shared by every backend
+  Workspaces.qml  LayoutSymbol.qml  Clock.qml  CpuGraph.qml  CpuTemp.qml
   Ram.qml  Disk.qml  Network.qml  Volume.qml  Tray.qml  Battery.qml
 ```

config/Compositor.qml

@@ -0,0 +1,35 @@
+pragma Singleton
+
+import Quickshell
+import QtQuick
+
+// Which window manager is driving this session? Detected once, from the
+// environment only.
+//
+// This deliberately does no IPC of its own. Widgets branch on these flags to
+// pick a backend, and reading a flag must never be able to instantiate the
+// service singleton for a window manager that isn't running -- an idle backend
+// would sit there retrying a socket that will never answer. Anything that
+// wants a backend gates on the matching flag first (`Compositor.isAttwm &&
+// Attwm.x`), relying on `&&` / `?:` to leave the other branch untouched.
+Singleton {
+    // Hyprland always exports this signature.
+    readonly property bool _hyprSig: !!Quickshell.env("HYPRLAND_INSTANCE_SIGNATURE")
+
+    // Sway and i3 both point clients at their IPC socket.
+    readonly property bool _i3Sock: !!Quickshell.env("SWAYSOCK")
+        || !!Quickshell.env("I3SOCK")
+
+    // attwm exports no signature of its own: it is a window management client
+    // of river rather than a compositor, so there is nothing session-wide to
+    // look for. Treat it as the fallback -- an explicit socket override wins
+    // outright, otherwise assume attwm once the two that do announce
+    // themselves are ruled out. Guessing wrong is cheap: everything attwm
+    // renders also gates on `Attwm.connected`, so a session with no window
+    // manager we recognise shows nothing rather than a row of dead tags.
+    readonly property bool isAttwm: !!Quickshell.env("ATTWM_SOCKET")
+        || (!_hyprSig && !_i3Sock)
+
+    readonly property bool isHyprland: !isAttwm && _hyprSig
+    readonly property bool isI3: !isAttwm && !isHyprland && _i3Sock
+}

config/qmldir

@@ -1,2 +1,3 @@
 singleton Theme 1.0 Theme.qml
 singleton Icons 1.0 Icons.qml
+singleton Compositor 1.0 Compositor.qml

services/Attwm.qml

@@ -0,0 +1,126 @@
+// Singleton service wrapping attwm's IPC socket.
+//
+// Adapted from the reference client that ships with attwm (quickshell/Attwm.qml
+// in that tree); keep the two in step when the state schema changes.
+//
+// One connection does both jobs: it subscribes to state, and commands are
+// written back down the same socket. attwm keeps subscribers connected after a
+// command precisely so a bar does not need a second connection or a process
+// spawn per click.
+//
+// Only instantiate this under attwm -- see Compositor.isAttwm. Merely reading a
+// property here opens the socket and starts the reconnect timer.
+
+pragma Singleton
+
+import QtQuick
+import Quickshell
+import Quickshell.Io
+
+Singleton {
+    id: root
+
+    // Latest state from attwm, parsed. Left untouched when the connection
+    // drops, so a restart of attwm freezes the bar on the last known state
+    // rather than blanking it for the second it takes to reconnect.
+    property var state: ({})
+
+    readonly property var outputs: state.outputs ?? []
+    readonly property var tagNames: state.tag_names ?? []
+    readonly property bool locked: state.locked ?? false
+    readonly property bool connected: socket.connected
+
+    // 0 until the first state object lands: the tag row is driven by this, and
+    // a default of 9 would paint a row of dead tags before (or without) attwm.
+    readonly property int tagCount: state.tag_count ?? 0
+
+    // The output the user is currently working on.
+    readonly property var focusedOutput: {
+        for (const o of outputs)
+            if (o.focused) return o;
+        return outputs.length > 0 ? outputs[0] : null;
+    }
+
+    readonly property string focusedTitle: {
+        if (!focusedOutput) return "";
+        for (const w of focusedOutput.windows)
+            if (w.focused) return w.title;
+        return "";
+    }
+
+    /// Look up an output by name, so a multi-monitor bar can show per-screen
+    /// state rather than the focused output's.
+    function outputFor(name) {
+        for (const o of outputs)
+            if (o.name === name) return o;
+        return null;
+    }
+
+    /// Send a command. Same grammar as attwmctl, e.g. send("view 3").
+    function send(command) {
+        if (socket.connected) socket.write(command + "\n");
+    }
+
+    // A tag is "occupied" if some window carries it, mirroring dwm's bar.
+    function tagOccupied(output, index) {
+        return output ? (output.occupied & (1 << index)) !== 0 : false;
+    }
+
+    function tagActive(output, index) {
+        return output ? (output.tags & (1 << index)) !== 0 : false;
+    }
+
+    Socket {
+        id: socket
+
+        // attwm names its socket after the Wayland display, so several river
+        // sessions can run side by side without colliding.
+        path: {
+            const explicit = Quickshell.env("ATTWM_SOCKET");
+            if (explicit) return explicit;
+            const dir = Quickshell.env("XDG_RUNTIME_DIR");
+            const display = Quickshell.env("WAYLAND_DISPLAY") || "wayland-0";
+            return `${dir}/attwm-${display}.sock`;
+        }
+
+        connected: true
+
+        onConnectionStateChanged: {
+            if (connected) {
+                // attwm replies with a full state object immediately, so there
+                // is no empty-bar flash on connect.
+                socket.write("subscribe\n");
+            } else {
+                reconnect.running = true;
+            }
+        }
+
+        parser: SplitParser {
+            onRead: line => {
+                // Command acknowledgements ("ok" / "err ...") share the stream
+                // with state objects; only the latter are JSON.
+                if (!line.startsWith("{")) return;
+                try {
+                    root.state = JSON.parse(line);
+                } catch (e) {
+                    console.warn("attwm: bad state line:", e);
+                }
+            }
+        }
+    }
+
+    // attwm may be restarted independently of the bar; keep trying.
+    Timer {
+        id: reconnect
+        interval: 1000
+        repeat: true
+        running: false
+        onTriggered: {
+            if (socket.connected) {
+                running = false;
+            } else {
+                socket.connected = true;
+            }
+        }
+    }
+}

services/qmldir

@@ -1 +1,2 @@
 singleton SysStats 1.0 SysStats.qml
+singleton Attwm 1.0 Attwm.qml

widgets/Bar.qml

@@ -35,7 +35,7 @@ PanelWindow {
     // depend on which row anything sits in, so this can't bind-loop.
     readonly property real neededWidth:
         (Theme.gap + 2) * 2                 // outer margins
-        + workspaces.implicitWidth
+        + leftRow.implicitWidth
         + Theme.gap * 4                     // breathing room between clusters
         + metricsRow.implicitWidth
         + Theme.gap
@@ -50,13 +50,23 @@ PanelWindow {
         color: Theme.barColor
     }
 
-    // row 1 left: workspaces
-    Workspaces {
-        id: workspaces
+    // row 1 left: workspaces, plus the layout symbol under attwm (hidden
+    // otherwise, and a hidden item takes no space in a RowLayout)
+    RowLayout {
+        id: leftRow
         anchors.left: parent.left
         anchors.leftMargin: Theme.gap + 2
         y: (Theme.barHeight - height) / 2
-        screen: panel.modelData
+        spacing: Theme.gap
+
+        Workspaces {
+            screen: panel.modelData
+            Layout.alignment: Qt.AlignVCenter
+        }
+        LayoutSymbol {
+            screen: panel.modelData
+            Layout.alignment: Qt.AlignVCenter
+        }
     }
 
     // row 1 right: clock, tray

widgets/LayoutSymbol.qml

@@ -0,0 +1,42 @@
+import QtQuick
+import QtQuick.Layouts
+import "../config"
+import "../services"
+
+// attwm's layout indicator: "[]=" master, "[M]" monocle, "|||" tabbed. Click
+// cycles forward, right-click back -- dwm's bar binding.
+//
+// Layout is per output, so this shows the monitor the bar is on, not the
+// focused one. Hidden entirely under any other window manager; the `&&` guards
+// short-circuit before Attwm is touched, so the socket is never opened there.
+MouseArea {
+    id: root
+    required property var screen
+
+    readonly property var output: Compositor.isAttwm
+        ? Attwm.outputFor(screen ? screen.name : "")
+        : null
+
+    visible: Compositor.isAttwm && Attwm.connected && !!output
+    implicitWidth: pill.implicitWidth
+    implicitHeight: pill.implicitHeight
+    cursorShape: Qt.PointingHandCursor
+    acceptedButtons: Qt.LeftButton | Qt.RightButton
+
+    onClicked: event => Attwm.send(event.button === Qt.RightButton
+        ? "cycle-layout prev"
+        : "cycle-layout next")
+
+    Pill {
+        id: pill
+        anchors.fill: parent
+
+        Text {
+            text: root.output ? root.output.layout_symbol : ""
+            font.family: Theme.monoFont
+            font.pixelSize: Theme.fontSize
+            color: Theme.subtext
+            Layout.alignment: Qt.AlignVCenter
+        }
+    }
+}

widgets/WorkspaceChip.qml

@@ -0,0 +1,66 @@
+import QtQuick
+import "../config"
+
+// One workspace/tag chip. Every backend renders through this, so the left end
+// of the bar looks the same whichever window manager is driving it.
+//
+// `dimmed` and `dot` are presentational rather than semantic on purpose: what
+// counts as "empty" differs per backend (i3 only lists workspaces that exist,
+// attwm always publishes all nine tags), so each call site decides and this
+// stays a plain renderer.
+Rectangle {
+    id: chip
+
+    property string label
+    property bool active: false    // shown on this monitor
+    property bool focused: false   // shown *and* holding input focus
+    property bool urgent: false
+    property bool dimmed: false    // exists, but nothing on it
+    property bool dot: false       // has windows but isn't shown (dwm's corner square)
+
+    signal clicked(int button)
+
+    implicitWidth: Math.max(implicitHeight, text.implicitWidth + 16)
+    implicitHeight: Theme.barHeight - Theme.gap * 2
+    width: implicitWidth
+    height: implicitHeight
+    radius: Theme.radius
+
+    color: urgent ? Theme.red
+         : focused ? Theme.blue
+         : active ? Theme.surface1
+         : Theme.surface0
+
+    Text {
+        id: text
+        anchors.centerIn: parent
+        text: chip.label
+        font.family: Theme.font
+        font.pixelSize: Theme.fontSize
+        font.bold: chip.focused || chip.urgent
+        color: (chip.focused || chip.urgent) ? Theme.mantle
+             : chip.dimmed ? Theme.overlay
+             : Theme.text
+    }
+
+    // dwm puts this in the tag's top-left corner, but the chip is only as wide
+    // as one digit -- a corner mark lands on the glyph. Underlining it says the
+    // same thing and suits the rounded chips.
+    Rectangle {
+        visible: chip.dot
+        anchors.horizontalCenter: parent.horizontalCenter
+        anchors.bottom: parent.bottom
+        anchors.bottomMargin: 4
+        width: 6
+        height: 2
+        radius: 1
+        color: Theme.blue
+    }
+
+    MouseArea {
+        anchors.fill: parent
+        cursorShape: Qt.PointingHandCursor
+        acceptedButtons: Qt.LeftButton | Qt.RightButton | Qt.MiddleButton
+        onClicked: event => chip.clicked(event.button)
+    }
+}

widgets/Workspaces.qml

@@ -4,59 +4,86 @@ import Quickshell
 import Quickshell.I3
 import Quickshell.Hyprland
 import "../config"
+import "../services"
 
-// Workspace switcher for a single monitor. Works on both Sway/i3 and Hyprland:
-// the compositor is detected once from its instance env var, and the matching
-// Quickshell backend model is used. The two backends expose the same item shape
-// (name / active / focused / urgent / monitor.name / activate()), so a single
-// chip renderer covers both. The `?:` on `model` only evaluates the taken
-// branch, so the unused backend singleton is never instantiated (no stray IPC).
+// Workspace switcher for a single monitor. Three backends, one chip renderer
+// (WorkspaceChip):
+//
+//   * Sway/i3 and Hyprland expose the same item shape (name / active / focused
+//     / urgent / monitor.name / activate()), so both feed the same Repeater.
+//   * attwm is a different model entirely -- nine fixed tags addressed by
+//     bitmask, several of which can be viewed at once -- so it gets its own
+//     Repeater over an index range.
+//
+// Exactly one of the two Repeaters is ever non-empty. The `?:` and `&&` guards
+// only evaluate the taken branch, which is what keeps the unused backend
+// singletons from being instantiated (no stray IPC) -- see Compositor.
 Row {
     id: root
     required property var screen   // ShellScreen this bar lives on
     spacing: Theme.gap
 
-    // Which compositor are we under? Hyprland always exports this signature.
-    readonly property bool isHyprland: !!Quickshell.env("HYPRLAND_INSTANCE_SIGNATURE")
-
     // Name of the output this bar is on, used to filter workspaces.
     readonly property string monitorName: screen ? screen.name : ""
 
-    Repeater {
-        model: root.isHyprland ? Hyprland.workspaces : I3.workspaces
+    // attwm keeps tags, layout and geometry per output, so the tag row on this
+    // bar reflects this monitor rather than whichever one has focus.
+    readonly property var attwmOutput: Compositor.isAttwm
+        ? Attwm.outputFor(monitorName)
+        : null
 
-        Rectangle {
-            id: chip
+    // ── Sway/i3 and Hyprland ────────────────────────────────────────────────
+    Repeater {
+        model: Compositor.isAttwm ? 0
+             : Compositor.isHyprland ? Hyprland.workspaces
+             : I3.workspaces
+
+        WorkspaceChip {
             required property var modelData
+
             // only show workspaces belonging to this monitor. Both I3Workspace
             // and HyprlandWorkspace expose .monitor as an object with a .name.
             visible: modelData.monitor && modelData.monitor.name === root.monitorName
-            width: visible ? Math.max(height, label.implicitWidth + 16) : 0
-            height: Theme.barHeight - Theme.gap * 2
-            radius: Theme.radius
 
-            readonly property bool isFocused: modelData.focused
-            readonly property bool isUrgent: modelData.urgent
+            label: modelData.name
+            active: modelData.active
+            focused: modelData.focused
+            urgent: modelData.urgent
 
-            color: isUrgent ? Theme.red
-                 : isFocused ? Theme.blue
-                 : modelData.active ? Theme.surface1
-                 : Theme.surface0
+            onClicked: modelData.activate()
+        }
+    }
 
-            Text {
-                id: label
-                anchors.centerIn: parent
-                text: chip.modelData.name
-                font.family: Theme.font
-                font.pixelSize: Theme.fontSize
-                font.bold: chip.isFocused || chip.isUrgent
-                color: (chip.isFocused || chip.isUrgent) ? Theme.mantle : Theme.text
-            }
+    // ── attwm ───────────────────────────────────────────────────────────────
+    Repeater {
+        // 0 until the socket has produced a state object, so nothing is drawn
+        // if we guessed the window manager wrong.
+        model: Compositor.isAttwm ? Attwm.tagCount : 0
 
-            MouseArea {
-                anchors.fill: parent
-                cursorShape: Qt.PointingHandCursor
-                onClicked: chip.modelData.activate()
+        WorkspaceChip {
+            id: tag
+            required property int index
+
+            readonly property bool viewing: Attwm.tagActive(root.attwmOutput, index)
+            readonly property bool occupied: Attwm.tagOccupied(root.attwmOutput, index)
+
+            label: Attwm.tagNames[index] ?? (index + 1)
+            active: viewing
+            // Tags are per output and several outputs can view a tag at once;
+            // only the focused output's get the focused colour.
+            focused: viewing && !!root.attwmOutput && root.attwmOutput.focused
+            dimmed: !viewing && !occupied
+            dot: occupied && !viewing
+
+            // dwm's mouse bindings: view / toggle into view / send window there.
+            onClicked: button => {
+                const n = index + 1;
+                if (button === Qt.RightButton)
+                    Attwm.send(`toggle-view ${n}`);
+                else if (button === Qt.MiddleButton)
+                    Attwm.send(`tag ${n}`);
+                else
+                    Attwm.send(`view ${n}`);
             }
         }
     }