free function to Self wrapper

command_list.zig

const std = @import("std");
const platform = @import("../platforms/platform.zig").platform;
const GpuResource = @import("gpu_resource.zig").GpuResource;

pub const CommandListKind = enum {
    Graphics,
    Compute,
    Copy,
};

pub const CommandListHandle = struct {
    index: u32 = 0,
};

pub const GraphicsCommandList = struct {
    handle: CommandListHandle,

    const Self = @This();

    pub const close = commandListForward(Self, doClose);
    pub const copyBufferRegion = commandListForward(Self, doCopyBufferRegion);
};

pub const ComputeCommandList = struct {
    handle: CommandListHandle,

    const Self = @This();

    pub const close = commandListForward(Self, doClose);
    pub const copyBufferRegion = commandListForward(Self, doCopyBufferRegion);
};

pub const CopyCommandList = struct {
    handle: CommandListHandle,

    const Self = @This();

    pub const close = commandListForward(Self, doClose);
    pub const copyBufferRegion = commandListForward(Self, doCopyBufferRegion);
};

fn doClose(handle: CommandListHandle) !void {
    return platform.gpu.commandListClose(handle);
}

fn doCopyBufferRegion(
    handle: CommandListHandle,
    destination_resource: GpuResource,
    destination_offset: u64,
    source_resource: GpuResource,
    source_offset: u64,
    num_bytes: u64,
) !void {
    return platform.gpu.commandListCopyBufferRegion(
        handle,
        destination_resource,
        destination_offset,
        source_resource,
        source_offset,
        num_bytes,
    );
}

fn functionArgCount(function: anytype) usize {
    const function_type = @TypeOf(function);
    const info = @typeInfo(function_type);
    if (info != .Fn) {
        @compileError("ArgsTuple expects a function type");
    }

    return info.Fn.args.len;
}

fn getFunctionReturnType(function: anytype) type {
    const function_type = @TypeOf(function);
    const info = @typeInfo(function_type);
    if (info != .Fn) {
        @compileError("ArgsTuple expects a function type");
    }
    return info.Fn.return_type.?;
}

fn getForwardReturnType(comptime T: type, function: anytype) type {
    return switch (functionArgCount(function) - 1) {
        0 => return fn (self: T) getFunctionReturnType(function),
        1 => return fn (self: T, arg1: anytype) getFunctionReturnType(function),
        2 => return fn (self: T, arg1: anytype, arg2: anytype) getFunctionReturnType(function),
        3 => return fn (self: T, arg1: anytype, arg2: anytype, arg3: anytype) getFunctionReturnType(function),
        4 => return fn (self: T, arg1: anytype, arg2: anytype, arg3: anytype, arg4: anytype) getFunctionReturnType(function),
        5 => return fn (self: T, arg1: anytype, arg2: anytype, arg3: anytype, arg4: anytype, arg5: anytype) getFunctionReturnType(function),
        6 => return fn (self: T, arg1: anytype, arg2: anytype, arg3: anytype, arg4: anytype, arg5: anytype, arg6: anytype) getFunctionReturnType(function),
        7 => return fn (self: T, arg1: anytype, arg2: anytype, arg3: anytype, arg4: anytype, arg5: anytype, arg6: anytype, arg7: anytype) getFunctionReturnType(function),
        8 => return fn (self: T, arg1: anytype, arg2: anytype, arg3: anytype, arg4: anytype, arg5: anytype, arg6: anytype, arg7: anytype, arg8: anytype) getFunctionReturnType(function),
        9 => return fn (self: T, arg1: anytype, arg2: anytype, arg3: anytype, arg4: anytype, arg5: anytype, arg6: anytype, arg7: anytype, arg8: anytype, arg9: anytype) getFunctionReturnType(function),
        else => @compileError("add thunk for more parameters"),
    };
}

fn commandListForward(comptime T: type, function: anytype) getForwardReturnType(T, function) {
    const thunk_struct = struct {
        fn thunk0(self: T) getFunctionReturnType(function) {
            return function(self.handle);
        }

        fn thunk1(
            self: T,
            arg1: anytype,
        ) getFunctionReturnType(function) {
            return function(
                self.handle,
                arg1,
            );
        }

        fn thunk2(
            self: T,
            arg1: anytype,
            arg2: anytype,
        ) getFunctionReturnType(function) {
            return function(
                self.handle,
                arg1,
                arg2,
            );
        }

        fn thunk3(
            self: T,
            arg1: anytype,
            arg2: anytype,
            arg3: anytype,
        ) getFunctionReturnType(function) {
            return function(
                self.handle,
                arg1,
                arg2,
                arg3,
            );
        }

        fn thunk4(
            self: T,
            arg1: anytype,
            arg2: anytype,
            arg3: anytype,
            arg4: anytype,
        ) getFunctionReturnType(function) {
            return function(
                self.handle,
                arg1,
                arg2,
                arg3,
                arg4,
            );
        }

        fn thunk5(
            self: T,
            arg1: anytype,
            arg2: anytype,
            arg3: anytype,
            arg4: anytype,
            arg5: anytype,
        ) getFunctionReturnType(function) {
            return function(
                self.handle,
                arg1,
                arg2,
                arg3,
                arg4,
                arg5,
            );
        }

        fn thunk6(
            self: T,
            arg1: anytype,
            arg2: anytype,
            arg3: anytype,
            arg4: anytype,
            arg5: anytype,
            arg6: anytype,
        ) getFunctionReturnType(function) {
            return function(
                self.handle,
                arg1,
                arg2,
                arg3,
                arg4,
                arg5,
                arg6,
            );
        }

        fn thunk7(
            self: T,
            arg1: anytype,
            arg2: anytype,
            arg3: anytype,
            arg4: anytype,
            arg5: anytype,
            arg6: anytype,
            arg7: anytype,
        ) getFunctionReturnType(function) {
            return function(
                self.handle,
                arg1,
                arg2,
                arg3,
                arg4,
                arg5,
                arg6,
                arg7,
            );
        }

        fn thunk8(
            self: T,
            arg1: anytype,
            arg2: anytype,
            arg3: anytype,
            arg4: anytype,
            arg5: anytype,
            arg6: anytype,
            arg7: anytype,
            arg8: anytype,
        ) getFunctionReturnType(function) {
            return function(
                self.handle,
                arg1,
                arg2,
                arg3,
                arg4,
                arg5,
                arg6,
                arg7,
                arg8,
            );
        }

        fn thunk9(
            self: T,
            arg1: anytype,
            arg2: anytype,
            arg3: anytype,
            arg4: anytype,
            arg5: anytype,
            arg6: anytype,
            arg7: anytype,
            arg8: anytype,
            arg9: anytype,
        ) getFunctionReturnType(function) {
            return function(
                self.handle,
                arg1,
                arg2,
                arg3,
                arg4,
                arg5,
                arg6,
                arg7,
                arg8,
                arg9,
            );
        }
    };

    return switch (functionArgCount(function) - 1) {
        0 => return thunk_struct.thunk0,
        1 => return thunk_struct.thunk1,
        2 => return thunk_struct.thunk2,
        3 => return thunk_struct.thunk3,
        4 => return thunk_struct.thunk4,
        5 => return thunk_struct.thunk5,
        6 => return thunk_struct.thunk6,
        7 => return thunk_struct.thunk7,
        8 => return thunk_struct.thunk8,
        9 => return thunk_struct.thunk9,
        else => @compileError("add thunk for more parameters"),
    };
}