Files
addr2line
adler
aho_corasick
ansi_term
arraydeque
as_slice
atty
backtrace
base64
bincode_core
bitflags
byteorder
bytes
capnp
capnp_futures
capnp_rpc
cfg_if
chrono
clap
ctrlc
derivative
dlib
downcast_rs
enumflags2
enumflags2_derive
evdev_rs
evdev_sys
failure
failure_derive
flexi_logger
futures
futures_channel
futures_core
futures_executor
futures_io
futures_macro
futures_sink
futures_task
futures_util
async_await
future
io
lock
sink
stream
task
generic_array
getrandom
gimli
glob
hash32
heapless
hid_io_core
hid_io_protocol
hidapi
install_service
lazy_static
libc
libloading
libudev_sys
log
memchr
memmap
miniz_oxide
mio
nanoid
nix
num_cpus
num_enum
num_enum_derive
num_integer
num_traits
object
once_cell
open
pem
pin_project_lite
pin_utils
ppv_lite86
proc_macro2
proc_macro_hack
proc_macro_nested
quote
rand
rand_chacha
rand_core
rcgen
regex
regex_syntax
remove_dir_all
ring
rustc_demangle
rustls
scoped_tls
sct
serde
serde_derive
slab
smallvec
spin
stable_deref_trait
strsim
syn
synstructure
sys_info
tempfile
textwrap
thiserror
thiserror_impl
time
tokio
future
io
loom
macros
net
park
runtime
stream
sync
task
time
util
tokio_macros
tokio_rustls
tokio_util
typenum
udev
uhid_virt
uhidrs_sys
unicode_width
unicode_xid
untrusted
vec_map
wayland_client
wayland_commons
wayland_sys
webpki
which
x11
xcb
xkbcommon
yansi
yasna
zwp_virtual_keyboard
 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
use proc_macro::{TokenStream, TokenTree};
use proc_macro2::Span;
use quote::quote;
use syn::Ident;

pub(crate) fn declare_output_enum(input: TokenStream) -> TokenStream {
    // passed in is: `(_ _ _)` with one `_` per branch
    let branches = match input.into_iter().next() {
        Some(TokenTree::Group(group)) => group.stream().into_iter().count(),
        _ => panic!("unexpected macro input"),
    };

    let variants = (0..branches)
        .map(|num| Ident::new(&format!("_{}", num), Span::call_site()))
        .collect::<Vec<_>>();

    // Use a bitfield to track which futures completed
    let mask = Ident::new(
        if branches <= 8 {
            "u8"
        } else if branches <= 16 {
            "u16"
        } else if branches <= 32 {
            "u32"
        } else if branches <= 64 {
            "u64"
        } else {
            panic!("up to 64 branches supported");
        },
        Span::call_site(),
    );

    TokenStream::from(quote! {
        pub(super) enum Out<#( #variants ),*> {
            #( #variants(#variants), )*
            // Include a `Disabled` variant signifying that all select branches
            // failed to resolve.
            Disabled,
        }

        pub(super) type Mask = #mask;
    })
}