river: add position and dimensions rules

This commit adds position and dimensions rules for configuring
the initial position and dimensions of views.

When a view is not matched by any position rules, it is centered
in the avaliable output space matching the current behavior. If
the provided position rule places the view outside of the output,
the view's position is clamped to the output bounds (with respect
to borders).

When a view is not matched by any dimensions rules, no default
dimensions is set by the server. If the provided dimensions rule
exceeds the minimum or maximum width/height constraints of the view,
the view's width/height is clamped to the constraints.

Position and dimensions rules have no effect if a view is started
fullscreen or is not floating. A view must be matched by a float
rule in order for them to take effect.

river/command/rule.zig

@@ -34,6 +34,8 @@ const Action = enum {
     csd,
     tag,
     output,
+    position,
+    dimensions,
 };
 
 pub fn ruleAdd(_: *Seat, args: []const [:0]const u8, _: *?[]const u8) Error!void {
@@ -51,6 +53,7 @@ pub fn ruleAdd(_: *Seat, args: []const [:0]const u8, _: *?[]const u8) Error!void
     const positional_arguments_count: u8 = switch (action) {
         .float, .@"no-float", .ssd, .csd => 1,
         .tag, .output => 2,
+        .position, .dimensions => 3,
     };
     if (result.args.len > positional_arguments_count) return Error.TooManyArguments;
     if (result.args.len < positional_arguments_count) return Error.NotEnoughArguments;
@@ -95,6 +98,30 @@ pub fn ruleAdd(_: *Seat, args: []const [:0]const u8, _: *?[]const u8) Error!void
                 .value = output_name,
             });
         },
+        .position => {
+            const x = try fmt.parseInt(u31, result.args[1], 10);
+            const y = try fmt.parseInt(u31, result.args[2], 10);
+            try server.config.position_rules.add(.{
+                .app_id_glob = app_id_glob,
+                .title_glob = title_glob,
+                .value = .{
+                    .x = x,
+                    .y = y,
+                },
+            });
+        },
+        .dimensions => {
+            const width = try fmt.parseInt(u31, result.args[1], 10);
+            const height = try fmt.parseInt(u31, result.args[2], 10);
+            try server.config.dimensions_rules.add(.{
+                .app_id_glob = app_id_glob,
+                .title_glob = title_glob,
+                .value = .{
+                    .width = width,
+                    .height = height,
+                },
+            });
+        },
     }
 }
 
@@ -132,6 +159,12 @@ pub fn ruleDel(_: *Seat, args: []const [:0]const u8, _: *?[]const u8) Error!void
                 util.gpa.free(output_rule);
             }
         },
+        .position => {
+            _ = server.config.position_rules.del(rule);
+        },
+        .dimensions => {
+            _ = server.config.dimensions_rules.del(rule);
+        },
     }
 }
 
@@ -153,12 +186,16 @@ pub fn listRules(_: *Seat, args: []const [:0]const u8, out: *?[]const u8) Error!
         ssd,
         tag,
         output,
+        position,
+        dimensions,
     }, args[1]) orelse return Error.UnknownOption;
     const max_glob_len = switch (list) {
         .float => server.config.float_rules.getMaxGlobLen(),
         .ssd => server.config.ssd_rules.getMaxGlobLen(),
         .tag => server.config.tag_rules.getMaxGlobLen(),
         .output => server.config.output_rules.getMaxGlobLen(),
+        .position => server.config.position_rules.getMaxGlobLen(),
+        .dimensions => server.config.dimensions_rules.getMaxGlobLen(),
     };
     const app_id_column_max = 2 + @max("app-id".len, max_glob_len.app_id);
     const title_column_max = 2 + @max("title".len, max_glob_len.title);
@@ -203,6 +240,22 @@ pub fn listRules(_: *Seat, args: []const [:0]const u8, out: *?[]const u8) Error!
                 try writer.print("{s}\n", .{rule.value});
             }
         },
+        .position => {
+            const rules = server.config.position_rules.rules.items;
+            for (rules) |rule| {
+                try fmt.formatBuf(rule.title_glob, .{ .width = title_column_max, .alignment = .left }, writer);
+                try fmt.formatBuf(rule.app_id_glob, .{ .width = app_id_column_max, .alignment = .left }, writer);
+                try writer.print("{d},{d}\n", .{ rule.value.x, rule.value.y });
+            }
+        },
+        .dimensions => {
+            const rules = server.config.dimensions_rules.rules.items;
+            for (rules) |rule| {
+                try fmt.formatBuf(rule.title_glob, .{ .width = title_column_max, .alignment = .left }, writer);
+                try fmt.formatBuf(rule.app_id_glob, .{ .width = app_id_column_max, .alignment = .left }, writer);
+                try writer.print("{d}x{d}\n", .{ rule.value.width, rule.value.height });
+            }
+        },
     }
 
     out.* = try buffer.toOwnedSlice();