serde/
lib.rs

1//! # Serde
2//!
3//! Serde is a framework for ***ser***ializing and ***de***serializing Rust data
4//! structures efficiently and generically.
5//!
6//! The Serde ecosystem consists of data structures that know how to serialize
7//! and deserialize themselves along with data formats that know how to
8//! serialize and deserialize other things. Serde provides the layer by which
9//! these two groups interact with each other, allowing any supported data
10//! structure to be serialized and deserialized using any supported data format.
11//!
12//! See the Serde website [https://serde.rs/] for additional documentation and
13//! usage examples.
14//!
15//! [https://serde.rs/]: https://serde.rs/
16//!
17//! ## Design
18//!
19//! Where many other languages rely on runtime reflection for serializing data,
20//! Serde is instead built on Rust's powerful trait system. A data structure
21//! that knows how to serialize and deserialize itself is one that implements
22//! Serde's `Serialize` and `Deserialize` traits (or uses Serde's derive
23//! attribute to automatically generate implementations at compile time). This
24//! avoids any overhead of reflection or runtime type information. In fact in
25//! many situations the interaction between data structure and data format can
26//! be completely optimized away by the Rust compiler, leaving Serde
27//! serialization to perform the same speed as a handwritten serializer for the
28//! specific selection of data structure and data format.
29//!
30//! ## Data formats
31//!
32//! The following is a partial list of data formats that have been implemented
33//! for Serde by the community.
34//!
35//! - [JSON], the ubiquitous JavaScript Object Notation used by many HTTP APIs.
36//! - [Bincode], a compact binary format
37//!   used for IPC within the Servo rendering engine.
38//! - [CBOR], a Concise Binary Object Representation designed for small message
39//!   size without the need for version negotiation.
40//! - [YAML], a self-proclaimed human-friendly configuration language that ain't
41//!   markup language.
42//! - [MessagePack], an efficient binary format that resembles a compact JSON.
43//! - [TOML], a minimal configuration format used by [Cargo].
44//! - [Pickle], a format common in the Python world.
45//! - [RON], a Rusty Object Notation.
46//! - [BSON], the data storage and network transfer format used by MongoDB.
47//! - [Avro], a binary format used within Apache Hadoop, with support for schema
48//!   definition.
49//! - [JSON5], A superset of JSON including some productions from ES5.
50//! - [Postcard], a no\_std and embedded-systems friendly compact binary format.
51//! - [URL] query strings, in the x-www-form-urlencoded format.
52//! - [Envy], a way to deserialize environment variables into Rust structs.
53//!   *(deserialization only)*
54//! - [Envy Store], a way to deserialize [AWS Parameter Store] parameters into
55//!   Rust structs. *(deserialization only)*
56//! - [S-expressions], the textual representation of code and data used by the
57//!   Lisp language family.
58//! - [D-Bus]'s binary wire format.
59//! - [FlexBuffers], the schemaless cousin of Google's FlatBuffers zero-copy serialization format.
60//!
61//! [JSON]: https://github.com/serde-rs/json
62//! [Bincode]: https://github.com/servo/bincode
63//! [CBOR]: https://github.com/pyfisch/cbor
64//! [YAML]: https://github.com/dtolnay/serde-yaml
65//! [MessagePack]: https://github.com/3Hren/msgpack-rust
66//! [TOML]: https://github.com/alexcrichton/toml-rs
67//! [Pickle]: https://github.com/birkenfeld/serde-pickle
68//! [RON]: https://github.com/ron-rs/ron
69//! [BSON]: https://github.com/zonyitoo/bson-rs
70//! [Avro]: https://github.com/flavray/avro-rs
71//! [JSON5]: https://github.com/callum-oakley/json5-rs
72//! [Postcard]: https://github.com/jamesmunns/postcard
73//! [URL]: https://docs.rs/serde_qs
74//! [Envy]: https://github.com/softprops/envy
75//! [Envy Store]: https://github.com/softprops/envy-store
76//! [Cargo]: http://doc.crates.io/manifest.html
77//! [AWS Parameter Store]: https://docs.aws.amazon.com/systems-manager/latest/userguide/systems-manager-paramstore.html
78//! [S-expressions]: https://github.com/rotty/lexpr-rs
79//! [D-Bus]: https://docs.rs/zvariant
80//! [FlexBuffers]: https://github.com/google/flatbuffers/tree/master/rust/flexbuffers
81
82////////////////////////////////////////////////////////////////////////////////
83
84// Serde types in rustdoc of other crates get linked to here.
85#![doc(html_root_url = "https://docs.rs/serde/1.0.116")]
86// Support using Serde without the standard library!
87#![cfg_attr(not(feature = "std"), no_std)]
88// Unstable functionality only if the user asks for it. For tracking and
89// discussion of these features please refer to this issue:
90//
91//    https://github.com/serde-rs/serde/issues/812
92#![cfg_attr(feature = "unstable", feature(never_type))]
93#![allow(unknown_lints, bare_trait_objects, deprecated)]
94#![cfg_attr(feature = "cargo-clippy", allow(renamed_and_removed_lints))]
95#![cfg_attr(feature = "cargo-clippy", deny(clippy, clippy_pedantic))]
96// Ignored clippy and clippy_pedantic lints
97#![cfg_attr(
98    feature = "cargo-clippy",
99    allow(
100        // clippy bug: https://github.com/rust-lang/rust-clippy/issues/5704
101        unnested_or_patterns,
102        // not available in our oldest supported compiler
103        checked_conversions,
104        empty_enum,
105        redundant_field_names,
106        redundant_static_lifetimes,
107        // integer and float ser/de requires these sorts of casts
108        cast_possible_truncation,
109        cast_possible_wrap,
110        cast_sign_loss,
111        // things are often more readable this way
112        cast_lossless,
113        module_name_repetitions,
114        option_if_let_else,
115        single_match_else,
116        type_complexity,
117        use_self,
118        zero_prefixed_literal,
119        // correctly used
120        enum_glob_use,
121        wildcard_imports,
122        // not practical
123        needless_pass_by_value,
124        similar_names,
125        too_many_lines,
126        // preference
127        doc_markdown,
128        unseparated_literal_suffix,
129        // false positive
130        needless_doctest_main,
131        // noisy
132        missing_errors_doc,
133        must_use_candidate,
134    )
135)]
136// Rustc lints.
137#![forbid(unsafe_code)]
138#![deny(missing_docs, unused_imports)]
139
140////////////////////////////////////////////////////////////////////////////////
141
142#[cfg(feature = "alloc")]
143extern crate alloc;
144
145/// A facade around all the types we need from the `std`, `core`, and `alloc`
146/// crates. This avoids elaborate import wrangling having to happen in every
147/// module.
148mod lib {
149    mod core {
150        #[cfg(not(feature = "std"))]
151        pub use core::*;
152        #[cfg(feature = "std")]
153        pub use std::*;
154    }
155
156    pub use self::core::{cmp, iter, mem, num, slice, str};
157    pub use self::core::{f32, f64};
158    pub use self::core::{i16, i32, i64, i8, isize};
159    pub use self::core::{u16, u32, u64, u8, usize};
160
161    pub use self::core::cell::{Cell, RefCell};
162    pub use self::core::clone::{self, Clone};
163    pub use self::core::convert::{self, From, Into};
164    pub use self::core::default::{self, Default};
165    pub use self::core::fmt::{self, Debug, Display};
166    pub use self::core::marker::{self, PhantomData};
167    pub use self::core::ops::Range;
168    pub use self::core::option::{self, Option};
169    pub use self::core::result::{self, Result};
170
171    #[cfg(all(feature = "alloc", not(feature = "std")))]
172    pub use alloc::borrow::{Cow, ToOwned};
173    #[cfg(feature = "std")]
174    pub use std::borrow::{Cow, ToOwned};
175
176    #[cfg(all(feature = "alloc", not(feature = "std")))]
177    pub use alloc::string::{String, ToString};
178    #[cfg(feature = "std")]
179    pub use std::string::{String, ToString};
180
181    #[cfg(all(feature = "alloc", not(feature = "std")))]
182    pub use alloc::vec::Vec;
183    #[cfg(feature = "std")]
184    pub use std::vec::Vec;
185
186    #[cfg(all(feature = "alloc", not(feature = "std")))]
187    pub use alloc::boxed::Box;
188    #[cfg(feature = "std")]
189    pub use std::boxed::Box;
190
191    #[cfg(all(feature = "rc", feature = "alloc", not(feature = "std")))]
192    pub use alloc::rc::{Rc, Weak as RcWeak};
193    #[cfg(all(feature = "rc", feature = "std"))]
194    pub use std::rc::{Rc, Weak as RcWeak};
195
196    #[cfg(all(feature = "rc", feature = "alloc", not(feature = "std")))]
197    pub use alloc::sync::{Arc, Weak as ArcWeak};
198    #[cfg(all(feature = "rc", feature = "std"))]
199    pub use std::sync::{Arc, Weak as ArcWeak};
200
201    #[cfg(all(feature = "alloc", not(feature = "std")))]
202    pub use alloc::collections::{BTreeMap, BTreeSet, BinaryHeap, LinkedList, VecDeque};
203    #[cfg(feature = "std")]
204    pub use std::collections::{BTreeMap, BTreeSet, BinaryHeap, LinkedList, VecDeque};
205
206    #[cfg(feature = "std")]
207    pub use std::{error, net};
208
209    #[cfg(feature = "std")]
210    pub use std::collections::{HashMap, HashSet};
211    #[cfg(feature = "std")]
212    pub use std::ffi::{CStr, CString, OsStr, OsString};
213    #[cfg(feature = "std")]
214    pub use std::hash::{BuildHasher, Hash};
215    #[cfg(feature = "std")]
216    pub use std::io::Write;
217    #[cfg(feature = "std")]
218    pub use std::num::Wrapping;
219    #[cfg(feature = "std")]
220    pub use std::path::{Path, PathBuf};
221    #[cfg(feature = "std")]
222    pub use std::sync::{Mutex, RwLock};
223    #[cfg(feature = "std")]
224    pub use std::time::{SystemTime, UNIX_EPOCH};
225
226    #[cfg(all(feature = "std", collections_bound))]
227    pub use std::collections::Bound;
228
229    #[cfg(core_reverse)]
230    pub use self::core::cmp::Reverse;
231
232    #[cfg(ops_bound)]
233    pub use self::core::ops::Bound;
234
235    #[cfg(range_inclusive)]
236    pub use self::core::ops::RangeInclusive;
237
238    #[cfg(all(feature = "std", std_atomic))]
239    pub use std::sync::atomic::{
240        AtomicBool, AtomicI16, AtomicI32, AtomicI8, AtomicIsize, AtomicU16, AtomicU32, AtomicU8,
241        AtomicUsize, Ordering,
242    };
243    #[cfg(all(feature = "std", std_atomic64))]
244    pub use std::sync::atomic::{AtomicI64, AtomicU64};
245
246    #[cfg(any(core_duration, feature = "std"))]
247    pub use self::core::time::Duration;
248}
249
250////////////////////////////////////////////////////////////////////////////////
251
252#[macro_use]
253mod macros;
254
255#[macro_use]
256mod integer128;
257
258pub mod de;
259pub mod ser;
260
261#[doc(inline)]
262pub use de::{Deserialize, Deserializer};
263#[doc(inline)]
264pub use ser::{Serialize, Serializer};
265
266// Generated code uses these to support no_std. Not public API.
267#[doc(hidden)]
268pub mod export;
269
270// Helpers used by generated code and doc tests. Not public API.
271#[doc(hidden)]
272pub mod private;
273
274#[cfg(not(feature = "std"))]
275mod std_error;
276
277// Re-export #[derive(Serialize, Deserialize)].
278//
279// The reason re-exporting is not enabled by default is that disabling it would
280// be annoying for crates that provide handwritten impls or data formats. They
281// would need to disable default features and then explicitly re-enable std.
282#[cfg(feature = "serde_derive")]
283#[allow(unused_imports)]
284#[macro_use]
285extern crate serde_derive;
286#[cfg(feature = "serde_derive")]
287#[doc(hidden)]
288pub use serde_derive::*;
serde/lib.rs

serde/
lib.rs
