Use mix-in design for interface abstraction.HEADmaster

2 files changed, 144 insertions, 0 deletions

diff --git a/src/object/interface.zig b/src/object/interface.zig
new file mode 100644
index 0000000..3098c46
--- /dev/null
+++ b/src/object/interface.zig
@@ -0,0 +1,68 @@
+const std = @import("std");
+const wayland = @import("../root.zig");
+const wl = wayland.wl;
+
+pub fn Init(T: type) type {
+    return struct {
+        const Self = @This();
+
+        pub fn default(
+            self: *Self,
+            ctx: wayland.Context,
+        ) !void {
+            const parent: *T = @alignCast(@fieldParentPtr("init", self));
+
+            parent.* = .{
+                .handle = try ctx.display.registry.add_object(
+                    ctx.allocator,
+                    wayland.Object.from_self(parent),
+                ),
+            };
+        }
+
+        pub fn with(
+            self: *Self,
+            ctx: wayland.Context,
+            values: T,
+        ) !void {
+            const parent: *T = @alignCast(@fieldParentPtr("init", self));
+            parent.* = values;
+            parent.handle = try ctx.display.registry.add_object(
+                ctx.allocator,
+                wayland.Object.from_self(parent),
+            );
+        }
+    };
+}
+
+pub fn Global(T: type) type {
+    return struct {
+        const Self = @This();
+
+        pub const init = Self { };
+        var instances: std.ArrayListUnmanaged(*T) = .empty;
+
+        comptime register: fn (ctx: wayland.Context) ?wayland.Object.Ref = reg,
+
+        pub fn reg(ctx: wayland.Context) ?wayland.Object.Ref {
+            const interface = ctx.allocator.create(T) catch return null;
+            interface.init.default(ctx) catch return null;
+
+            instances.append(ctx.allocator, interface) catch return null;
+            return interface.handle;
+        }
+
+        pub fn as_slice(self: *Self) []*T {
+            _ = self;
+            return instances.items;
+        }
+
+        pub fn get(self: *Self, index: usize) ?*T {
+            _ = self;
+            if (index >= instances.items.len) {
+                return null;
+            }
+            return instances.items[index];
+        }
+    };
+}
diff --git a/src/object/root.zig b/src/object/root.zig
new file mode 100644
index 0000000..1895d3f
--- /dev/null
+++ b/src/object/root.zig
@@ -0,0 +1,76 @@
+const std = @import("std");
+const wayland = @import("../root.zig");
+
+const Self = @This();
+
+pub const interface = @import("interface.zig");
+
+pub const Ref = struct {
+    id: u32,
+
+    pub const @"null": @This() = .{
+        .id = 0,
+    };
+
+    pub const display: @This() = .{
+        .id = 1,
+    };
+
+    pub const registry: @This() = .{
+        .id = 2,
+    };
+};
+
+const VTable = struct {
+    on_event: *const fn (
+        ptr: *anyopaque,
+        ctx: wayland.Context,
+        opcode: u16,
+        args: []const u8,
+    ) void,
+};
+
+ptr: ?*anyopaque,
+vtable: VTable,
+name: []const u8,
+
+pub inline fn on_event(
+    self: *Self,
+    ctx: wayland.Context,
+    opcode: u16,
+    args: []const u8,
+) !void {
+    if (self.ptr) |ptr| {
+        self.vtable.on_event(ptr, ctx, opcode, args);
+    } else {
+        return error.UseAfterRelease;
+    }
+}
+
+pub inline fn from_self(ptr: anytype) Self {
+    const T = @TypeOf(ptr.*);
+
+    return .{
+        .ptr = ptr,
+        .vtable = VTable{
+            .on_event = T.Events.on_event,
+        },
+        .name = @typeName(T),
+    };
+}
+
+pub fn disable(self: *Self) void {
+    self.ptr = null;
+}
+
+pub fn format(
+    self: *const Self,
+    comptime fmt: []const u8,
+    options: std.fmt.FormatOptions,
+    writer: anytype,
+) !void {
+    _ = fmt;
+    _ = options;
+
+    try writer.print("Object<{s}> {{ {?} }}", .{self.name, self.ptr});
+}