First sketch of wayland interface

**WARNING** this implementation is not working properly yet.

1 files changed, 265 insertions, 0 deletions

diff --git a/src/wl/display.zig b/src/wl/display.zig
new file mode 100644
index 0000000..4f04746
--- /dev/null
+++ b/src/wl/display.zig
@@ -0,0 +1,265 @@
+const std = @import("std");
+const wayland = @import("../root.zig");
+const wl = wayland.wl;
+
+const log = std.log.scoped(.display);
+
+const Self = @This();
+
+pub const Error = enum(u32) {
+    invalid_object = 0,
+    invalid_method = 1,
+    no_memory = 2,
+    implementation = 3,
+};
+
+pub const Request = union(enum) {
+    sync: struct { *wayland.Object },
+    get_registry: struct { *wayland.Object },
+};
+
+pub const Events = wayland.EventSet(Self, .{
+    err,
+    delete_id,
+});
+
+stream: std.net.Stream,
+interface: wayland.Object,
+registry: wl.Registry,
+
+pub fn init(
+    self: *Self,
+    allocator: std.mem.Allocator,
+    handlers: []const wl.Registry.GlobalHandler,
+) !void {
+    self.interface = wayland.Object.from_self(self);
+    try self.registry.init(allocator, self, handlers);
+}
+
+pub fn from_fd(fd: std.posix.fd_t) void {
+    var self: Self = undefined;
+    self.stream = std.net.Stream{ .handle = fd };
+    return self;
+}
+
+pub fn open(path: []const u8) !Self {
+    var self: Self = undefined;
+    self.stream = try std.net.connectUnixSocket(path);
+    return self;
+}
+
+pub fn close(self: *Self) void {
+    self.stream.close();
+}
+
+pub fn open_default(allocator: std.mem.Allocator) !Self {
+    const path = try default_path(allocator);
+    defer allocator.free(path);
+    return open(path);
+}
+
+pub fn default_path(allocator: std.mem.Allocator) ![]const u8 {
+    const env = try std.process.getEnvMap(allocator);
+    const xdg_runtime_dir = env.get("XDG_RUNTIME_DIR") orelse return error.MissingRuntimeDir;
+    const wayland_display = env.get("WAYLAND_DISPLAY") orelse "wayland-0";
+    return std.fmt.allocPrint(allocator, "{s}/{s}", .{ xdg_runtime_dir, wayland_display });
+}
+
+pub fn request(self: *Self, object: anytype, args: @TypeOf(object.*).Request) !void {
+    comptime std.debug.assert(@FieldType(@TypeOf(object.*), "interface") == wayland.Object);
+    comptime std.debug.assert(@typeInfo(@TypeOf(object.*).Request) == .@"union");
+    const tag_type = @typeInfo(@TypeOf(args)).@"union".tag_type.?;
+    const opcode: u32 = @intFromEnum(args);
+
+    inline for (@typeInfo(tag_type).@"enum".fields) |f| {
+        if (f.value == opcode) {
+            const data = @field(args, f.name);
+            const id = object.interface.id orelse return error.UnregisteredObject;
+
+            var size: u32 = 8;
+
+            inline for (data) |value| {
+                switch (@TypeOf(value)) {
+                    u32, i32 => |t| size += @sizeOf(t),
+                    *wayland.Object => size += @sizeOf(u32),
+                    []const u8, []u8 => {
+                        const padding_size: usize = @mod(@as(usize, @bitCast(-@as(isize, @intCast(value.len + 1)))), 4);
+                        size += @as(u32, @intCast(@sizeOf(u32) + (value.len + 1) + padding_size));
+                    },
+                    else => |t| switch (@typeInfo(t)) {
+                        .pointer => |ptr| if (ptr.size == .slice) {
+                            const padding_size: usize = @mod(@as(usize, @bitCast(-@as(isize, @intCast(value.len * @sizeOf(ptr.child))))), 4);
+                            size += @intCast(@sizeOf(u32) + (value.len * @sizeOf(ptr.child)) + padding_size);
+                        } else @compileError(std.fmt.comptimePrint("size: unsupported type {}", .{t})),
+                        else => @compileError(std.fmt.comptimePrint("size: unsupported type {}", .{t})),
+                    },
+                }
+            }
+
+            _ = try self.stream.writeAll(&std.mem.toBytes(id));
+            _ = try self.stream.writeAll(&std.mem.toBytes((size << 16) | opcode));
+
+            inline for (data) |value| {
+                switch (@TypeOf(value)) {
+                    u32, i32 => _ = try self.stream.writeAll(std.mem.asBytes(&value)),
+                    *wayland.Object => try self.stream.writeAll(std.mem.asBytes(&(value.id orelse return error.UnregisteredObject))),
+                    []const u8, []u8 => {
+                        const padding_size: usize = @mod(@as(usize, @bitCast(-@as(isize, @intCast(value.len + 1)))), 4);
+                        _ = try self.stream.writeAll(std.mem.asBytes(&@as(u32, @truncate(value.len + 1))));
+                        _ = try self.stream.writeAll(value);
+                        for (0..padding_size + 1) |_| {
+                            _ = try self.stream.writeAll(std.mem.asBytes(&@as(u8, 0)));
+                        }
+                    },
+                    else => |t| switch (@typeInfo(t)) {
+                        .pointer => |ptr| if (ptr.size == .slice) {
+                            const padding_size: usize = @mod(@as(usize, @bitCast(-@as(isize, @intCast(value.len * @sizeOf(ptr.child))))), 4);
+                            _ = try self.stream.writeAll(std.mem.asBytes(&@as(u32, @truncate(value.len))));
+                            _ = try self.stream.writeAll(std.mem.sliceAsBytes(value));
+                            for (0..padding_size) |_| {
+                                _ = try self.stream.writeAll(std.mem.asBytes(&@as(u8, 0)));
+                            }
+                        } else @compileError(std.fmt.comptimePrint("size: unsupported type {}", .{t})),
+                        else => @compileError(std.fmt.comptimePrint("size: unsupported type {}", .{t})),
+                    },
+                }
+            }
+            return;
+        }
+    }
+
+    return error.InvalidOpcode;
+}
+
+pub fn roundtrip(self: *Self, allocator: std.mem.Allocator) !void {
+    var done = false;
+    var callback: wl.Callback = undefined;
+    try callback.init(allocator, self, &done);
+
+    var context: wayland.Context = .{
+        .display = self,
+        .allocator = allocator,
+    };
+
+    while (!done) {
+        const endian = @import("builtin").target.cpu.arch.endian();
+        const reader = self.stream.reader();
+
+        const object_id = try reader.readInt(u32, endian);
+
+        const message_info = try reader.readInt(u32, endian);
+
+        const opcode: u16 = @truncate(message_info & 0xffff);
+        const size: u16 = @truncate(((message_info >> 16) & 0xffff));
+        const body_size = size - 2 * @sizeOf(u32);
+
+        const body = try allocator.alloc(u8, body_size);
+        defer allocator.free(body);
+        _ = try reader.readAll(body);
+
+        if (object_id >= self.registry.objects.items.len) {
+            return error.UnregisteredObject;
+        }
+
+        if (self.registry.objects.items[object_id]) |object| {
+            try object.on_event(&context, opcode, body);
+        } else {
+            return error.UnregisteredObject;
+        }
+    }
+}
+
+fn err(
+    self: *Self,
+    ctx: *wayland.Context,
+    object: *wayland.Object,
+    code: u32,
+    message: []const u8,
+) void {
+    _ = self;
+    _ = ctx;
+    log.err("{} ({}): {s}", .{ object, code, message });
+}
+
+fn delete_id(
+    self: *Self,
+    ctx: *wayland.Context,
+    id: u32,
+) void {
+    _ = ctx;
+    self.registry.release_object(id);
+}
+
+test "request" {
+    const Sample = struct {
+        pub const Request = union(enum) {
+            req1: struct { u32 },
+            req2: struct { *wayland.Object },
+            req3: struct { []const u8 },
+            req4: struct { []const u16 },
+        };
+
+        pub const Events = wayland.EventSet(@This(), .{});
+
+        interface: wayland.Object,
+
+        pub fn init(self: *@This()) void {
+            self.interface = wayland.Object.from_self(self);
+        }
+    };
+
+    const in, const out = try std.posix.pipe();
+    defer std.posix.close(in);
+
+    {
+        var sample: Sample = undefined;
+        sample.init();
+        sample.interface.id = 42;
+
+        var displ: Self = .from_fd(out);
+        defer displ.close();
+        try displ.init();
+        try displ.request(sample, .{ .req1 = .{432} });
+        try displ.request(sample, .{ .req2 = .{&sample.interface} });
+        try displ.request(sample, .{ .req3 = .{"abcd"} });
+        try displ.request(sample, .{ .req4 = .{&[_]u16{ 1, 32, 4, 5, 5 }} });
+    }
+
+    const file = std.fs.File{ .handle = in };
+    var test_buffer: [64]u8 = undefined;
+    _ = try file.readAll(test_buffer[0..12]);
+    try std.testing.expectEqualSlices(
+        u8,
+        &(std.mem.toBytes(@as(u32, 42)) ++
+            std.mem.toBytes(@as(u32, (12 << 16) | 0)) ++
+            std.mem.toBytes(@as(u32, 432))),
+        test_buffer[0..12],
+    );
+
+    _ = try file.readAll(test_buffer[0..12]);
+    try std.testing.expectEqualSlices(
+        u8,
+        &(std.mem.toBytes(@as(u32, 42)) ++
+            std.mem.toBytes(@as(u32, (12 << 16) | 1)) ++
+            std.mem.toBytes(@as(u32, 42))),
+        test_buffer[0..12],
+    );
+
+    _ = try file.readAll(test_buffer[0..20]);
+    try std.testing.expectEqualSlices(
+        u8,
+        &(std.mem.toBytes(@as(u32, 42)) ++
+            std.mem.toBytes(@as(u32, (20 << 16) | 2)) ++
+            std.mem.toBytes(@as(u32, 5))) ++ "abcd\x00\x00\x00\x00",
+        test_buffer[0..20],
+    );
+
+    _ = try file.readAll(test_buffer[0..24]);
+    try std.testing.expectEqualSlices(
+        u8,
+        &(std.mem.toBytes(@as(u32, 42)) ++
+            std.mem.toBytes(@as(u32, (24 << 16) | 3)) ++
+            std.mem.toBytes(@as(u32, 5))) ++ std.mem.toBytes([_]u16{ 1, 32, 4, 5, 5, 0 }),
+        test_buffer[0..24],
+    );
+}