xmonad shell: admit multiple displays

1 files changed, 21 insertions, 12 deletions

diff --git a/pkgs/haskell/xmonad-tv/shell.nix b/pkgs/haskell/xmonad-tv/shell.nix
index c50bdd9..859d1ea 100644
--- a/pkgs/haskell/xmonad-tv/shell.nix
+++ b/pkgs/haskell/xmonad-tv/shell.nix
@@ -20,6 +20,12 @@ in
 
   lib.overrideDerivation xmonadDrv.env (oldAttrs: {
     shellHook = ''
+      display=$(echo "$DISPLAY" | sed -rn 's/^:([0-9]+)(\.[0-9]+)?$/\1/p')
+      if test -z "$display"; then
+        echo "Error: unsupported display name “$DISPLAY”" >&2
+        exit -1
+      fi
+
       pkg_name=${mylib.shell.escape (builtins.baseNameOf (toString ./.))}
 
       WORKDIR=${toString ./src}
@@ -28,12 +34,15 @@ in
 
       mkdir -p "$CACHEDIR"
 
-      config_XMONAD_CACHE_DIR=${mylib.shell.escape
-        config.systemd.services.xmonad.environment.XMONAD_CACHE_DIR
-      }
-
+      service=xmonad@$display.service
       xmonad=$CACHEDIR/xmonad-${builtins.currentSystem}
 
+      service_XMONAD_CACHE_DIR=$(
+        systemctl show "$service" --property=Environment |
+        tr \  \\n |
+        sed -rn 's/^XMONAD_CACHE_DIR=//p'
+      )
+
       xmonad_build() {(
         set -efu
         cd "$WORKDIR"
@@ -50,9 +59,9 @@ in
       xmonad_restart() {(
         set -efu
         cd "$WORKDIR"
-        if systemctl --quiet is-active xmonad; then
-          sudo systemctl stop xmonad
-          cp -b "$config_XMONAD_CACHE_DIR"/xmonad.state "$CACHEDIR"/
+        if systemctl --quiet is-active "$service"; then
+          systemctl stop "$service"
+          cp -b "$service_XMONAD_CACHE_DIR"/xmonad.state "$CACHEDIR"/
           echo "xmonad.state: $(cat "$CACHEDIR"/xmonad.state)"
         else
           "$xmonad" --shutdown || :
@@ -63,17 +72,17 @@ in
 
       xmonad_yield() {(
         set -efu
-        if ! systemctl --quiet is-active xmonad; then
+        if ! systemctl --quiet is-active "$service"; then
           "$xmonad" --shutdown
-          cp -b "$CACHEDIR"/xmonad.state "$config_XMONAD_CACHE_DIR"/
-          sudo systemctl start xmonad
+          cp -b "$CACHEDIR"/xmonad.state "$service_XMONAD_CACHE_DIR"/
+          systemctl start "$service"
         else
-          echo "xmonad.service is already running" >&2
+          echo "$service is already running" >&2
           exit -1
         fi
       )}
 
-      export PATH=${config.systemd.services.xmonad.path}:$PATH
+      export PATH=${lib.makeBinPath (config.systemd.services."xmonad@".path)}:$PATH
       export SHELL=/run/current-system/sw/bin/bash
 
       export XMONAD_CACHE_DIR="$CACHEDIR"