htop: support screens configuration

`htop` has changed the singular fields list to a configuration of multiple
screens. Each screen has a name and its own set of fields to show, plus some
options to control sorting and view style (tree or flat). Screen names can be
shown with the `screen_tabs` setting. Fields in screens are set with their names
(as strings) rather than numbers.

Extend the htop module to allow configuring screens with a defined set of
options. Order the screens with dag topology. Configurations without screens are
converted automatically by `htop` on load.

This feature was requested in #3616.

modules/programs/htop.nix

@@ -76,21 +76,6 @@ let
     M_PSSWP = 120;
   };
 
-  defaultFields = with fields; [
-    PID
-    USER
-    PRIORITY
-    NICE
-    M_SIZE
-    M_RESIDENT
-    M_SHARE
-    STATE
-    PERCENT_CPU
-    PERCENT_MEM
-    TIME
-    COMM
-  ];
-
   modes = {
     Bar = 1;
     Text = 2;
@@ -106,6 +91,48 @@ let
   led = meter modes.LED;
   blank = text "Blank";
 
+  screenOptions = {
+    name = mkOption { type = types.str; };
+
+    fields = mkOption {
+      type = types.oneOf [ types.str (types.listOf types.str) ];
+      default = "PID USER M_VIRT STATE PERCENT_CPU PERCENT_MEM TIME Command";
+    };
+
+    all_branches_collapsed = mkOption {
+      type = types.bool;
+      default = false;
+    };
+
+    sort_direction = mkOption {
+      type = types.enum [ (-1) 1 ];
+      default = -1;
+    };
+    sort_key = mkOption {
+      type = types.str;
+      example = "PERCENT_MEM";
+    };
+
+    tree_sort_direction = mkOption {
+      type = types.enum [ (-1) 1 ];
+      default = -1;
+    };
+    tree_sort_key = mkOption {
+      type = types.str;
+      example = "PERCENT_MEM";
+    };
+
+    tree_view = mkOption {
+      type = types.bool;
+      default = false;
+    };
+
+    tree_view_always_by_pid = mkOption {
+      type = types.bool;
+      default = false;
+    };
+  };
+
 in {
   meta.maintainers = [ hm.maintainers.bjpbakker ];
 
@@ -156,6 +183,38 @@ in {
       '';
     };
 
+    screens = mkOption {
+      type = hm.types.dagOf (types.submodule ({ dagName, ... }: {
+        options = screenOptions;
+        config.name = mkDefault dagName;
+      }));
+      default = { };
+      example = literalExpression ''
+        {
+          "Main" = {
+            fields = "PID USER PRIORITY NICE M_VIRT M_RESIDENT M_SHARE STATE PERCENT_CPU PERCENT_MEM TIME Command";
+            sort_key = "PERCENT_MEM";
+            tree_sort_key = "PERCENT_MEM";
+            tree_view = false;
+            tree_view_always_by_pid = false;
+            sort_direction = -1;
+            tree_sort_direction = -1;
+            all_branches_collapsed = false;
+          };
+          "I/O" = lib.hm.dag.entryAfter ["Main"] {
+            fields = "PID STATE STARTTIME M_RESIDENT COMM EXE USER IO_PRIORITY IO_RATE IO_READ_RATE IO_WRITE_RATE";
+            sort_key = "IO_RATE";
+            tree_sort_key = "PID";
+            tree_view = false;
+            tree_view_always_by_pid = false;
+            sort_direction = -1;
+            tree_sort_direction = -1;
+            all_branches_collapsed = false;
+          };
+        };
+      '';
+    };
+
     package = mkOption {
       type = types.package;
       default = pkgs.htop;
@@ -172,25 +231,55 @@ in {
     home.packages = [ cfg.package ];
 
     xdg.configFile."htop/htoprc" = let
-      defaults = {
-        fields = if isDarwin then
-          remove fields.M_SHARE defaultFields
-        else
-          defaultFields;
-      };
-
-      before = optionalAttrs (cfg.settings ? header_layout) {
-        inherit (cfg.settings) header_layout;
-      };
-
-      settings = defaults // (removeAttrs cfg.settings (attrNames before));
-
       formatOptions = mapAttrsToList formatOption;
 
-    in mkIf (cfg.settings != { }) {
-      text =
-        concatStringsSep "\n" (formatOptions before ++ formatOptions settings)
-        + "\n";
+      hasScreens = cfg.screens != { };
+
+      settings = let
+        # old (no screen) configuration support
+        defaultFields = let
+          defaults = with fields; [
+            PID
+            USER
+            PRIORITY
+            NICE
+            M_SIZE
+            M_RESIDENT
+            M_SHARE
+            STATE
+            PERCENT_CPU
+            PERCENT_MEM
+            TIME
+            COMM
+          ];
+        in if isDarwin then remove fields.M_SHARE defaults else defaults;
+
+        oldDefaults = optionalAttrs (!hasScreens) { fields = defaultFields; };
+
+        leading = optionalAttrs (cfg.settings ? header_layout) {
+          inherit (cfg.settings) header_layout;
+        };
+
+        settings' = oldDefaults
+          // (removeAttrs cfg.settings (attrNames leading));
+      in formatOptions leading ++ formatOptions settings';
+
+      screens = let
+        formatOption' = k: formatOption ".${k}";
+        formatScreen = { name, fields, ... }@screen:
+          let
+            options = removeAttrs screen [ "fields" "name" ];
+            newScreen = "screen:${formatOption name fields}";
+          in [ newScreen ] ++ mapAttrsToList formatOption' options;
+
+        screens' = let sorted = hm.dag.topoSort cfg.screens;
+        in sorted.result or (abort
+          "Dependency cycle in htop screens: ${builtins.toJSON sorted}");
+
+      in concatMap (x: formatScreen x.data) screens';
+
+    in mkIf (cfg.settings != { } || hasScreens) {
+      text = concatStringsSep "\n" (settings ++ screens) + "\n";
     };
   };
 }

tests/modules/programs/htop/default.nix

@@ -2,5 +2,6 @@
   htop-empty-settings = ./empty-settings.nix;
   htop-example-settings = ./example-settings.nix;
   htop-header_layout = ./header_layout.nix;
+  htop-screens = ./screens.nix;
   htop-settings-without-fields = ./settings-without-fields.nix;
 }

tests/modules/programs/htop/screens.nix

@@ -0,0 +1,39 @@
+{ lib, ... }:
+
+{
+  programs.htop.enable = true;
+  programs.htop.settings = { screen_tabs = true; };
+  programs.htop.screens = {
+    "Main" = {
+      fields =
+        "PID USER PRIORITY NICE M_VIRT M_RESIDENT M_SHARE STATE PERCENT_CPU PERCENT_MEM TIME Command";
+      sort_key = "PERCENT_MEM";
+      tree_sort_key = "PERCENT_MEM";
+      tree_view = false;
+      tree_view_always_by_pid = false;
+      sort_direction = -1;
+      tree_sort_direction = -1;
+      all_branches_collapsed = false;
+    };
+    "I/O" = lib.hm.dag.entryAfter [ "Main" ] {
+      fields =
+        "PID STATE STARTTIME M_RESIDENT COMM EXE USER IO_PRIORITY IO_RATE IO_READ_RATE IO_WRITE_RATE";
+      sort_key = "IO_RATE";
+      tree_sort_key = "PID";
+      tree_view = false;
+      tree_view_always_by_pid = false;
+      sort_direction = -1;
+      tree_sort_direction = -1;
+      all_branches_collapsed = false;
+    };
+  };
+
+  test.stubs.htop = { };
+
+  nmt.script = ''
+    htoprc=home-files/.config/htop/htoprc
+    assertFileExists $htoprc
+    assertFileContent $htoprc ${./screens.txt}
+  '';
+
+}

tests/modules/programs/htop/screens.txt

@@ -0,0 +1,17 @@
+screen_tabs=1
+screen:Main=PID USER PRIORITY NICE M_VIRT M_RESIDENT M_SHARE STATE PERCENT_CPU PERCENT_MEM TIME Command
+.all_branches_collapsed=0
+.sort_direction=-1
+.sort_key=PERCENT_MEM
+.tree_sort_direction=-1
+.tree_sort_key=PERCENT_MEM
+.tree_view=0
+.tree_view_always_by_pid=0
+screen:I/O=PID STATE STARTTIME M_RESIDENT COMM EXE USER IO_PRIORITY IO_RATE IO_READ_RATE IO_WRITE_RATE
+.all_branches_collapsed=0
+.sort_direction=-1
+.sort_key=IO_RATE
+.tree_sort_direction=-1
+.tree_sort_key=PID
+.tree_view=0
+.tree_view_always_by_pid=0