zx/
macros.rs

1// Copyright 2024 The Fuchsia Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5// Implements the HandleBased traits for a Handle newtype struct
6macro_rules! impl_handle_based {
7    ($type_name:path) => {
8        impl AsHandleRef for $type_name {
9            fn as_handle_ref(&self) -> HandleRef<'_> {
10                self.0.as_handle_ref()
11            }
12        }
13
14        impl From<Handle> for $type_name {
15            fn from(handle: Handle) -> Self {
16                $type_name(handle)
17            }
18        }
19
20        impl From<$type_name> for Handle {
21            fn from(x: $type_name) -> Handle {
22                x.0
23            }
24        }
25
26        impl HandleBased for $type_name {}
27    };
28}
29
30/// Convenience macro for creating get/set property functions on an object.
31///
32/// This is for use when the underlying property type is a simple raw type.
33/// It creates an empty 'tag' struct to implement the relevant PropertyQuery*
34/// traits against. One, or both, of a getter and setter may be defined
35/// depending upon what the property supports. Example usage is
36/// unsafe_handle_propertyes!(ObjectType[get_foo_prop,set_foo_prop:FooPropTag,FOO,u32;]);
37/// unsafe_handle_properties!(object: Foo,
38///     props: [
39///         {query_ty: FOO_BAR, tag: FooBarTag, prop_ty: usize, get:get_bar},
40///         {query_ty: FOO_BAX, tag: FooBazTag, prop_ty: u32, set:set_baz},
41///     ]
42/// );
43/// And will create
44/// Foo::get_bar(&self) -> Result<usize, Status>
45/// Foo::set_baz(&self, val: &u32) -> Result<(), Status>
46/// Using Property::FOO as the underlying property.
47///
48///  # Safety
49///
50/// This macro will implement unsafe traits on your behalf and any combination
51/// of query_ty and prop_ty must respect the Safety requirements detailed on the
52/// PropertyQuery trait.
53macro_rules! unsafe_handle_properties {
54    (
55        object: $object_ty:ty,
56        props: [$( {
57            query_ty: $query_ty:ident,
58            tag: $query_tag:ident,
59            prop_ty: $prop_ty:ty
60            $(,get: $get:ident)*
61            $(,set: $set:ident)*
62            $(,)*
63        }),*$(,)*]
64    ) => {
65        $(
66            struct $query_tag {}
67            unsafe impl PropertyQuery for $query_tag {
68                const PROPERTY: Property = Property::$query_ty;
69                type PropTy = $prop_ty;
70            }
71
72            $(
73                impl $object_ty {
74                    pub fn $get(&self) -> Result<$prop_ty, Status> {
75                        object_get_property::<$query_tag>(self.as_handle_ref())
76                    }
77                }
78            )*
79
80            $(
81                impl $object_ty {
82                    pub fn $set(&self, val: &$prop_ty) -> Result<(), Status> {
83                        object_set_property::<$query_tag>(self.as_handle_ref(), val)
84                    }
85                }
86            )*
87        )*
88    }
89}
90
91// Creates associated constants of TypeName of the form
92// `pub const NAME: TypeName = TypeName(path::to::value);`
93// and provides a private `assoc_const_name` method and a `Debug` implementation
94// for the type based on `$name`.
95// If multiple names match, the first will be used in `name` and `Debug`.
96#[macro_export]
97macro_rules! assoc_values {
98    ($typename:ident, [$($(#[$attr:meta])* $name:ident = $value:path;)*]) => {
99        #[allow(non_upper_case_globals)]
100        impl $typename {
101            $(
102                $(#[$attr])*
103                pub const $name: $typename = $typename($value);
104            )*
105
106            fn assoc_const_name(&self) -> Option<&'static str> {
107                match self.0 {
108                    $(
109                        $(#[$attr])*
110                        $value => Some(stringify!($name)),
111                    )*
112                    _ => None,
113                }
114            }
115        }
116
117        impl ::std::fmt::Debug for $typename {
118            fn fmt(&self, f: &mut ::std::fmt::Formatter<'_>) -> ::std::fmt::Result {
119                f.write_str(concat!(stringify!($typename), "("))?;
120                match self.assoc_const_name() {
121                    Some(name) => f.write_str(&name)?,
122                    None => ::std::fmt::Debug::fmt(&self.0, f)?,
123                }
124                f.write_str(")")
125            }
126        }
127    }
128}
129
130/// Declare a struct that needs to be statically aligned with another, equivalent struct. The syntax
131/// is the following:
132/// rust```
133/// static_assert_align! (
134///     #[derive(Trait1, Trait2)]
135///     <other_aligned_struct> pub struct MyStruct {
136///         field_1 <equivalent_field1_on_other_struct>: bool,
137///         field_2 <equivalent_field2_on_other_struct>: u32,
138///         special_field_3: [u8; 10],  // This field will be ignored when comparing alignment.
139///     }
140/// );
141/// ```
142macro_rules! static_assert_align {
143    (
144        $(#[$attrs:meta])* <$equivalent:ty> $vis:vis struct $struct_name:ident {
145            $($field_vis:vis $field_ident:ident $(<$field_eq:ident>)?: $field_type:ty,)*
146        }
147    ) => {
148        $(#[$attrs])* $vis struct $struct_name {
149            $($field_vis $field_ident: $field_type,)*
150        }
151
152        static_assertions::assert_eq_size!($struct_name, $equivalent);
153        $(_static_assert_one_field!($struct_name, $field_ident, $equivalent $(, $field_eq)?);)*
154    }
155}
156
157/// Internal macro used by [static_assert_align].
158macro_rules! _static_assert_one_field {
159    ($struct_1:ty, $field_1:ident, $struct_2:ty) => {};
160    ($struct_1:ty, $field_1:ident, $struct_2:ty, $field_2:ident) => {
161        static_assertions::const_assert_eq!(
162            std::mem::offset_of!($struct_1, $field_1),
163            std::mem::offset_of!($struct_2, $field_2)
164        );
165    };
166}
zx/macros.rs

zx/
macros.rs
