river: Allow applying CSD based on window titles

This extends the `csd-filter-add` command to allow matching on window
titles as well, using a `csd-filter-add kind pattern` syntax. The
following kinds are supported:

  * `title`, which matches window titles
  * `app-id`, which matches app ids

Only exact matches are considered.

As an example following configuration applies client-side decorations to
all windows with the title 'asdf with spaces'.

    riverctl csd-filter-add title 'asdf with spaces'

6 files changed, 80 insertions, 34 deletions

diff --git a/doc/riverctl.1.scd b/doc/riverctl.1.scd
index 68cbbb6..dcb2148 100644
--- a/doc/riverctl.1.scd
+++ b/doc/riverctl.1.scd
@@ -28,15 +28,15 @@ over the Wayland protocol.
 *close*
 	Close the focused view.
 
-*csd-filter-add* _app-id_
-	Add _app-id_ to the CSD filter list. Views with this _app-id_ are
-	told to use client side decoration instead of the default server
-	side decoration. Note that this affects both new views, as well as already
-	existing ones.
-
-*csd-filter-remove* _app-id_
-	Remove an _app-id_ from the CSD filter list. Note that this affects both new
-	views, as well as already existing ones.
+*csd-filter-add* *app-id*|*title* _pattern_
+	Add _pattern_ to the CSD filter list. Views with this _pattern_ are told to
+	use client side decoration instead of the default server side decoration.
+	Note that this affects new views as well as already existing ones. Title
+	updates are not taken into account.
+
+*csd-filter-remove* *app-id*|*title* _pattern_
+	Remove _pattern_ from the CSD filter list. Note that this affects new views
+	as well as already existing ones.
 
 *exit*
 	Exit the compositor, terminating the Wayland session.
diff --git a/example/init b/example/init
index d3b9dc3..7ddd8eb 100755
--- a/example/init
+++ b/example/init
@@ -152,8 +152,8 @@ riverctl set-repeat 50 300
 riverctl float-filter-add app-id float
 riverctl float-filter-add title "popup title with spaces"
 
-# Set app-ids of views which should use client side decorations
-riverctl csd-filter-add "gedit"
+# Set app-ids and titles of views which should use client side decorations
+riverctl csd-filter-add app-id "gedit"
 
 # Set and exec into the default layout generator, rivertile.
 # River will send the process group of the init executable SIGTERM on exit.
diff --git a/river/Config.zig b/river/Config.zig
index 113264c..56d2bbe 100644
--- a/river/Config.zig
+++ b/river/Config.zig
@@ -62,8 +62,9 @@ modes: std.ArrayList(Mode),
 float_filter_app_ids: std.StringHashMapUnmanaged(void) = .{},
 float_filter_titles: std.StringHashMapUnmanaged(void) = .{},
 
-/// Set of app_ids which are allowed to use client side decorations
-csd_filter: std.StringHashMapUnmanaged(void) = .{},
+/// Sets of app_ids and titles which are allowed to use client side decorations
+csd_filter_app_ids: std.StringHashMapUnmanaged(void) = .{},
+csd_filter_titles: std.StringHashMapUnmanaged(void) = .{},
 
 /// The selected focus_follows_cursor mode
 focus_follows_cursor: FocusFollowsCursorMode = .disabled,
@@ -133,9 +134,15 @@ pub fn deinit(self: *Self) void {
     }
 
     {
-        var it = self.csd_filter.keyIterator();
+        var it = self.csd_filter_app_ids.keyIterator();
         while (it.next()) |key| util.gpa.free(key.*);
-        self.csd_filter.deinit(util.gpa);
+        self.csd_filter_app_ids.deinit(util.gpa);
+    }
+
+    {
+        var it = self.csd_filter_titles.keyIterator();
+        while (it.next()) |key| util.gpa.free(key.*);
+        self.csd_filter_titles.deinit(util.gpa);
     }
 
     util.gpa.free(self.default_layout_namespace);
@@ -156,3 +163,19 @@ pub fn shouldFloat(self: Self, view: *View) bool {
 
     return false;
 }
+
+pub fn csdAllowed(self: Self, view: *View) bool {
+    if (view.getAppId()) |app_id| {
+        if (self.csd_filter_app_ids.contains(std.mem.span(app_id))) {
+            return true;
+        }
+    }
+
+    if (view.getTitle()) |title| {
+        if (self.csd_filter_titles.contains(std.mem.span(title))) {
+            return true;
+        }
+    }
+
+    return false;
+}
diff --git a/river/Decoration.zig b/river/Decoration.zig
index 4159bc6..45263ac 100644
--- a/river/Decoration.zig
+++ b/river/Decoration.zig
@@ -26,6 +26,7 @@ const server = &@import("main.zig").server;
 const util = @import("util.zig");
 
 const Server = @import("Server.zig");
+const View = @import("View.zig");
 
 xdg_toplevel_decoration: *wlr.XdgToplevelDecorationV1,
 
@@ -62,8 +63,8 @@ fn handleRequestMode(
 ) void {
     const self = @fieldParentPtr(Self, "request_mode", listener);
 
-    const toplevel = self.xdg_toplevel_decoration.surface.role_data.toplevel;
-    if (toplevel.app_id != null and server.config.csd_filter.contains(mem.span(toplevel.app_id.?))) {
+    const view = @intToPtr(*View, self.xdg_toplevel_decoration.surface.data);
+    if (server.config.csdAllowed(view)) {
         _ = self.xdg_toplevel_decoration.setMode(.client_side);
     } else {
         _ = self.xdg_toplevel_decoration.setMode(.server_side);
diff --git a/river/XdgToplevel.zig b/river/XdgToplevel.zig
index b837c0d..1606e6a 100644
--- a/river/XdgToplevel.zig
+++ b/river/XdgToplevel.zig
@@ -218,9 +218,9 @@ fn handleMap(listener: *wl.Listener(*wlr.XdgSurface), xdg_surface: *wlr.XdgSurfa
         view.pending.box = view.float_box;
     }
 
-    // If the toplevel has an app_id which is not configured to use client side
-    // decorations, inform it that it is tiled.
-    if (toplevel.app_id != null and server.config.csd_filter.contains(mem.span(toplevel.app_id.?))) {
+    // If the view has an app_id or title which is not configured to use client
+    // side decorations, inform it that it is tiled.
+    if (server.config.csdAllowed(view)) {
         view.draw_borders = false;
     } else {
         _ = toplevel.setTiled(.{ .top = true, .bottom = true, .left = true, .right = true });
diff --git a/river/command/filter.zig b/river/command/filter.zig
index 6d6ac35..298b56d 100644
--- a/river/command/filter.zig
+++ b/river/command/filter.zig
@@ -79,15 +79,22 @@ pub fn csdFilterAdd(
     args: []const [:0]const u8,
     out: *?[]const u8,
 ) Error!void {
-    if (args.len < 2) return Error.NotEnoughArguments;
-    if (args.len > 2) return Error.TooManyArguments;
+    if (args.len < 3) return Error.NotEnoughArguments;
+    if (args.len > 3) return Error.TooManyArguments;
+
+    const kind = std.meta.stringToEnum(FilterKind, args[1]) orelse return Error.UnknownOption;
+    const map = switch (kind) {
+        .@"app-id" => &server.config.csd_filter_app_ids,
+        .title => &server.config.csd_filter_titles,
+    };
 
-    const gop = try server.config.csd_filter.getOrPut(util.gpa, args[1]);
+    const key = args[2];
+    const gop = try map.getOrPut(util.gpa, key);
     if (gop.found_existing) return;
-    errdefer assert(server.config.csd_filter.remove(args[1]));
-    gop.key_ptr.* = try std.mem.dupe(util.gpa, u8, args[1]);
+    errdefer assert(map.remove(key));
+    gop.key_ptr.* = try std.mem.dupe(util.gpa, u8, key);
 
-    csdFilterUpdateViews(args[1], .add);
+    csdFilterUpdateViews(kind, key, .add);
 }
 
 pub fn csdFilterRemove(
@@ -96,23 +103,29 @@ pub fn csdFilterRemove(
     args: []const [:0]const u8,
     out: *?[]const u8,
 ) Error!void {
-    if (args.len < 2) return Error.NotEnoughArguments;
-    if (args.len > 2) return Error.TooManyArguments;
+    if (args.len < 3) return Error.NotEnoughArguments;
+    if (args.len > 3) return Error.TooManyArguments;
+
+    const kind = std.meta.stringToEnum(FilterKind, args[1]) orelse return Error.UnknownOption;
+    const map = switch (kind) {
+        .@"app-id" => &server.config.csd_filter_app_ids,
+        .title => &server.config.csd_filter_titles,
+    };
 
-    if (server.config.csd_filter.fetchRemove(args[1])) |kv| {
+    const key = args[2];
+    if (map.fetchRemove(key)) |kv| {
         util.gpa.free(kv.key);
-        csdFilterUpdateViews(args[1], .remove);
+        csdFilterUpdateViews(kind, key, .remove);
     }
 }
 
-fn csdFilterUpdateViews(app_id: []const u8, operation: enum { add, remove }) void {
+fn csdFilterUpdateViews(kind: FilterKind, pattern: []const u8, operation: enum { add, remove }) void {
     var decoration_it = server.decoration_manager.decorations.first;
     while (decoration_it) |decoration_node| : (decoration_it = decoration_node.next) {
         const xdg_toplevel_decoration = decoration_node.data.xdg_toplevel_decoration;
-        const view = @intToPtr(*View, xdg_toplevel_decoration.surface.data);
-        const view_app_id = mem.span(view.getAppId()) orelse continue;
 
-        if (mem.eql(u8, app_id, view_app_id)) {
+        const view = @intToPtr(*View, xdg_toplevel_decoration.surface.data);
+        if (viewMatchesPattern(kind, pattern, view)) {
             const toplevel = view.impl.xdg_toplevel.xdg_surface.role_data.toplevel;
             switch (operation) {
                 .add => {
@@ -129,3 +142,12 @@ fn csdFilterUpdateViews(app_id: []const u8, operation: enum { add, remove }) voi
         }
     }
 }
+
+fn viewMatchesPattern(kind: FilterKind, pattern: []const u8, view: *View) bool {
+    const p = switch (kind) {
+        .@"app-id" => mem.span(view.getAppId()),
+        .title => mem.span(view.getTitle()),
+    } orelse return false;
+
+    return mem.eql(u8, pattern, p);
+}