286 lines
9.4 KiB
Rust
286 lines
9.4 KiB
Rust
// this file is borrowed in its entirety until macro_reexport stabilizes.
|
|
// https://github.com/rust-lang/rust/issues/29638
|
|
|
|
// Copyright 2017 Serde Developers
|
|
//
|
|
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
|
|
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
|
|
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
|
|
// option. This file may not be copied, modified, or distributed
|
|
// except according to those terms.
|
|
|
|
/// Construct a `serde_json::Value` from a JSON literal.
|
|
///
|
|
/// ```rust
|
|
/// # #[macro_use]
|
|
/// # extern crate serde_json;
|
|
/// #
|
|
/// # fn main() {
|
|
/// let value = json!({
|
|
/// "code": 200,
|
|
/// "success": true,
|
|
/// "payload": {
|
|
/// "features": [
|
|
/// "serde",
|
|
/// "json"
|
|
/// ]
|
|
/// }
|
|
/// });
|
|
/// # }
|
|
/// ```
|
|
///
|
|
/// Variables or expressions can be interpolated into the JSON literal. Any type
|
|
/// interpolated into an array element or object value must implement Serde's
|
|
/// `Serialize` trait, while any type interpolated into a object key must
|
|
/// implement `Into<String>`. If the `Serialize` implementation of the
|
|
/// interpolated type decides to fail, or if the interpolated type contains a
|
|
/// map with non-string keys, the `json!` macro will panic.
|
|
///
|
|
/// ```rust
|
|
/// # #[macro_use]
|
|
/// # extern crate serde_json;
|
|
/// #
|
|
/// # fn main() {
|
|
/// let code = 200;
|
|
/// let features = vec!["serde", "json"];
|
|
///
|
|
/// let value = json!({
|
|
/// "code": code,
|
|
/// "success": code == 200,
|
|
/// "payload": {
|
|
/// features[0]: features[1]
|
|
/// }
|
|
/// });
|
|
/// # }
|
|
/// ```
|
|
///
|
|
/// Trailing commas are allowed inside both arrays and objects.
|
|
///
|
|
/// ```rust
|
|
/// # #[macro_use]
|
|
/// # extern crate serde_json;
|
|
/// #
|
|
/// # fn main() {
|
|
/// let value = json!([
|
|
/// "notice",
|
|
/// "the",
|
|
/// "trailing",
|
|
/// "comma -->",
|
|
/// ]);
|
|
/// # }
|
|
/// ```
|
|
#[macro_export]
|
|
macro_rules! json {
|
|
// Hide distracting implementation details from the generated rustdoc.
|
|
($($json:tt)+) => {
|
|
json_internal!($($json)+)
|
|
};
|
|
}
|
|
|
|
// Rocket relies on this because they export their own `json!` with a different
|
|
// doc comment than ours, and various Rust bugs prevent them from calling our
|
|
// `json!` from their `json!` so they call `json_internal!` directly. Check with
|
|
// @SergioBenitez before making breaking changes to this macro.
|
|
//
|
|
// Changes are fine as long as `json_internal!` does not call any new helper
|
|
// macros and can still be invoked as `json_internal!($($json)+)`.
|
|
#[macro_export]
|
|
#[doc(hidden)]
|
|
macro_rules! json_internal {
|
|
//////////////////////////////////////////////////////////////////////////
|
|
// TT muncher for parsing the inside of an array [...]. Produces a vec![...]
|
|
// of the elements.
|
|
//
|
|
// Must be invoked as: json_internal!(@array [] $($tt)*)
|
|
//////////////////////////////////////////////////////////////////////////
|
|
|
|
// Done with trailing comma.
|
|
(@array [$($elems:expr,)*]) => {
|
|
vec![$($elems,)*]
|
|
};
|
|
|
|
// Done without trailing comma.
|
|
(@array [$($elems:expr),*]) => {
|
|
vec![$($elems),*]
|
|
};
|
|
|
|
// Next element is `null`.
|
|
(@array [$($elems:expr,)*] null $($rest:tt)*) => {
|
|
json_internal!(@array [$($elems,)* json_internal!(null)] $($rest)*)
|
|
};
|
|
|
|
// Next element is `true`.
|
|
(@array [$($elems:expr,)*] true $($rest:tt)*) => {
|
|
json_internal!(@array [$($elems,)* json_internal!(true)] $($rest)*)
|
|
};
|
|
|
|
// Next element is `false`.
|
|
(@array [$($elems:expr,)*] false $($rest:tt)*) => {
|
|
json_internal!(@array [$($elems,)* json_internal!(false)] $($rest)*)
|
|
};
|
|
|
|
// Next element is an array.
|
|
(@array [$($elems:expr,)*] [$($array:tt)*] $($rest:tt)*) => {
|
|
json_internal!(@array [$($elems,)* json_internal!([$($array)*])] $($rest)*)
|
|
};
|
|
|
|
// Next element is a map.
|
|
(@array [$($elems:expr,)*] {$($map:tt)*} $($rest:tt)*) => {
|
|
json_internal!(@array [$($elems,)* json_internal!({$($map)*})] $($rest)*)
|
|
};
|
|
|
|
// Next element is an expression followed by comma.
|
|
(@array [$($elems:expr,)*] $next:expr, $($rest:tt)*) => {
|
|
json_internal!(@array [$($elems,)* json_internal!($next),] $($rest)*)
|
|
};
|
|
|
|
// Last element is an expression with no trailing comma.
|
|
(@array [$($elems:expr,)*] $last:expr) => {
|
|
json_internal!(@array [$($elems,)* json_internal!($last)])
|
|
};
|
|
|
|
// Comma after the most recent element.
|
|
(@array [$($elems:expr),*] , $($rest:tt)*) => {
|
|
json_internal!(@array [$($elems,)*] $($rest)*)
|
|
};
|
|
|
|
//////////////////////////////////////////////////////////////////////////
|
|
// TT muncher for parsing the inside of an object {...}. Each entry is
|
|
// inserted into the given map variable.
|
|
//
|
|
// Must be invoked as: json_internal!(@object $map () ($($tt)*) ($($tt)*))
|
|
//
|
|
// We require two copies of the input tokens so that we can match on one
|
|
// copy and trigger errors on the other copy.
|
|
//////////////////////////////////////////////////////////////////////////
|
|
|
|
// Done.
|
|
(@object $object:ident () () ()) => {};
|
|
|
|
// Insert the current entry followed by trailing comma.
|
|
(@object $object:ident [$($key:tt)+] ($value:expr) , $($rest:tt)*) => {
|
|
$object.insert(($($key)+).into(), $value);
|
|
json_internal!(@object $object () ($($rest)*) ($($rest)*));
|
|
};
|
|
|
|
// Insert the last entry without trailing comma.
|
|
(@object $object:ident [$($key:tt)+] ($value:expr)) => {
|
|
$object.insert(($($key)+).into(), $value);
|
|
};
|
|
|
|
// Next value is `null`.
|
|
(@object $object:ident ($($key:tt)+) (: null $($rest:tt)*) $copy:tt) => {
|
|
json_internal!(@object $object [$($key)+] (json_internal!(null)) $($rest)*);
|
|
};
|
|
|
|
// Next value is `true`.
|
|
(@object $object:ident ($($key:tt)+) (: true $($rest:tt)*) $copy:tt) => {
|
|
json_internal!(@object $object [$($key)+] (json_internal!(true)) $($rest)*);
|
|
};
|
|
|
|
// Next value is `false`.
|
|
(@object $object:ident ($($key:tt)+) (: false $($rest:tt)*) $copy:tt) => {
|
|
json_internal!(@object $object [$($key)+] (json_internal!(false)) $($rest)*);
|
|
};
|
|
|
|
// Next value is an array.
|
|
(@object $object:ident ($($key:tt)+) (: [$($array:tt)*] $($rest:tt)*) $copy:tt) => {
|
|
json_internal!(@object $object [$($key)+] (json_internal!([$($array)*])) $($rest)*);
|
|
};
|
|
|
|
// Next value is a map.
|
|
(@object $object:ident ($($key:tt)+) (: {$($map:tt)*} $($rest:tt)*) $copy:tt) => {
|
|
json_internal!(@object $object [$($key)+] (json_internal!({$($map)*})) $($rest)*);
|
|
};
|
|
|
|
// Next value is an expression followed by comma.
|
|
(@object $object:ident ($($key:tt)+) (: $value:expr , $($rest:tt)*) $copy:tt) => {
|
|
json_internal!(@object $object [$($key)+] (json_internal!($value)) , $($rest)*);
|
|
};
|
|
|
|
// Last value is an expression with no trailing comma.
|
|
(@object $object:ident ($($key:tt)+) (: $value:expr) $copy:tt) => {
|
|
json_internal!(@object $object [$($key)+] (json_internal!($value)));
|
|
};
|
|
|
|
// Missing value for last entry. Trigger a reasonable error message.
|
|
(@object $object:ident ($($key:tt)+) (:) $copy:tt) => {
|
|
// "unexpected end of macro invocation"
|
|
json_internal!();
|
|
};
|
|
|
|
// Missing colon and value for last entry. Trigger a reasonable error
|
|
// message.
|
|
(@object $object:ident ($($key:tt)+) () $copy:tt) => {
|
|
// "unexpected end of macro invocation"
|
|
json_internal!();
|
|
};
|
|
|
|
// Misplaced colon. Trigger a reasonable error message.
|
|
(@object $object:ident () (: $($rest:tt)*) ($colon:tt $($copy:tt)*)) => {
|
|
// Takes no arguments so "no rules expected the token `:`".
|
|
unimplemented!($colon);
|
|
};
|
|
|
|
// Found a comma inside a key. Trigger a reasonable error message.
|
|
(@object $object:ident ($($key:tt)*) (, $($rest:tt)*) ($comma:tt $($copy:tt)*)) => {
|
|
// Takes no arguments so "no rules expected the token `,`".
|
|
unimplemented!($comma);
|
|
};
|
|
|
|
// Key is fully parenthesized. This avoids clippy double_parens false
|
|
// positives because the parenthesization may be necessary here.
|
|
(@object $object:ident () (($key:expr) : $($rest:tt)*) $copy:tt) => {
|
|
json_internal!(@object $object ($key) (: $($rest)*) (: $($rest)*));
|
|
};
|
|
|
|
// Munch a token into the current key.
|
|
(@object $object:ident ($($key:tt)*) ($tt:tt $($rest:tt)*) $copy:tt) => {
|
|
json_internal!(@object $object ($($key)* $tt) ($($rest)*) ($($rest)*));
|
|
};
|
|
|
|
//////////////////////////////////////////////////////////////////////////
|
|
// The main implementation.
|
|
//
|
|
// Must be invoked as: json_internal!($($json)+)
|
|
//////////////////////////////////////////////////////////////////////////
|
|
|
|
(null) => {
|
|
$crate::SerdeValue::Null
|
|
};
|
|
|
|
(true) => {
|
|
$crate::SerdeValue::Bool(true)
|
|
};
|
|
|
|
(false) => {
|
|
$crate::SerdeValue::Bool(false)
|
|
};
|
|
|
|
([]) => {
|
|
$crate::SerdeValue::Array(vec![])
|
|
};
|
|
|
|
([ $($tt:tt)+ ]) => {
|
|
$crate::SerdeValue::Array(json_internal!(@array [] $($tt)+))
|
|
};
|
|
|
|
({}) => {
|
|
$crate::SerdeValue::Object($crate::SerdeMap::new())
|
|
};
|
|
|
|
({ $($tt:tt)+ }) => {
|
|
$crate::SerdeValue::Object({
|
|
let mut object = $crate::SerdeMap::new();
|
|
json_internal!(@object object () ($($tt)+) ($($tt)+));
|
|
object
|
|
})
|
|
};
|
|
|
|
// Any Serialize type: numbers, strings, struct literals, variables etc.
|
|
// Must be below every other rule.
|
|
($other:expr) => {
|
|
$crate::serde_to_value(&$other).unwrap()
|
|
};
|
|
}
|