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 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333
//! A query language for Serde data model.
//!
//! This crate provides [`serde_query::Deserialize`] and [`serde_query::DeserializeQuery`] derive
//! macros that generate [`serde::Deserialize`] implementations with queries.
//!
//! # Example
//!
//! ```rust
//! # use std::error::Error;
//! # fn main() -> Result<(), Box<dyn Error + 'static>> {
//! use serde_query::Deserialize;
//!
//! #[derive(Deserialize)]
//! struct Data {
//! #[query(".commits.[].author")]
//! authors: Vec<String>,
//! #[query(".count")]
//! count: usize,
//! }
//!
//! let document = serde_json::json!({
//! "commits": [
//! {
//! "author": "Kou",
//! "hash": 0x0202,
//! },
//! {
//! "author": "Kasumi",
//! "hash": 0x1013,
//! },
//! {
//! "author": "Masaru",
//! "hash": 0x0809,
//! },
//! ],
//! "count": 3,
//! }).to_string();
//!
//! let data: Data = serde_json::from_str(&document)?;
//!
//! assert_eq!(data.authors, vec!["Kou", "Kasumi", "Masaru"]);
//! assert_eq!(data.count, 3);
//! # Ok(())
//! # }
//! ```
//!
//! # Derive macros
//!
//! This crate provides the following derive macros for declaring queries:
//! * [`serde_query::Deserialize`] generates an implementation of [`serde::Deserialize`] for the struct.
//! We recommend using a full-path form (`serde_query::Deserialize`) when deriving to disambiguate
//! between serde and this crate.
//! * [`serde_query::DeserializeQuery`] generates [`serde::Deserialize`] for [`Query<T>`] wrapper.
//! This derive macro is useful if you want two `Deserialize` implementation.
//! For example, you may want `DeserializeQuery` for querying an API and `Deserialize` for loading from file.
//!
//! # Using the `#[query("...")]` annotation
//!
//! serde-query let you write a jq-like query inside the `#[query("...")]` annotation.
//! Note that every field must have a query annotation.
//!
//! The supported syntaxes are as follows:
//!
//! * **`.field` syntax:** You can use the `.field` syntax to extract a field from a struct.
//! For example, `.name` extracts the `name` field. If the field name contains special characters, you can use the `.["field"]` syntax to quote the field name.
//! For example, `.["first-name"]` extracts the `first-name` field.
//! When quoting a field name, try using a raw string literal (i.e., `#[query(r#"..."#)]`).
//! * **`.[]` syntax:** You can use the `.[]` syntax to run the rest of the query for each element in an array and collect the results.
//! For example, `.friends.[].name` extracts the `name` field from each element in the `friends` array.
//! * **`.[n]` syntax:** You can use the `.[n]` syntax to extract the nth element from an array.
//! For example, `.friends.[0]` extracts the first element of the `friends` array.
//!
//! [`serde::Deserialize`]: https://docs.serde.rs/serde/trait.Deserialize.html
//! [`serde_query::Deserialize`]: derive.Deserialize.html
//! [`serde_query::DeserializeQuery`]: trait.DeserializeQuery.html
//! [`Query<T>`]: trait.DeserializeQuery.html#associatedtype.Query
/// Derive macro that generates [`serde::Deserialize`] directly.
///
/// Please refer to the [module-level documentation] for the usage.
///
/// [`serde::Deserialize`]: https://docs.serde.rs/serde/trait.Deserialize.html
/// [module-level documentation]: index.html
pub use serde_query_derive::Deserialize;
/// Derive macro for [`DeserializeQuery`] trait.
///
/// Please refer to the [module-level documentation] for the usage.
///
/// # Example
///
/// ```rust
/// # use std::error::Error;
/// # fn main() -> Result<(), Box<dyn Error + 'static>> {
/// use serde_query::{DeserializeQuery, Query};
///
/// #[derive(DeserializeQuery)]
/// struct Data {
/// #[query(".commits.[].author")]
/// authors: Vec<String>,
/// #[query(".count")]
/// count: usize,
/// }
///
/// let document = serde_json::json!({
/// "commits": [
/// {
/// "author": "Kou",
/// "hash": 0x0202,
/// },
/// {
/// "author": "Kasumi",
/// "hash": 0x1013,
/// },
/// {
/// "author": "Masaru",
/// "hash": 0x0809,
/// },
/// ],
/// "count": 3,
/// }).to_string();
///
/// // You can use `Query<T>` as a `Deserialize` type for any `Deserializer`
/// // and convert the result to the desired type using `From`/`Into`.
/// let data: Data = serde_json::from_str::<Query<Data>>(&document)?.into();
///
/// assert_eq!(data.authors, vec!["Kou", "Kasumi", "Masaru"]);
/// assert_eq!(data.count, 3);
/// # Ok(())
/// # }
/// ```
///
/// [`DeserializeQuery`]: trait.DeserializeQuery.html
/// [module-level documentation]: index.html
pub use serde_query_derive::DeserializeQuery;
use core::ops::{Deref, DerefMut};
use serde::de::Deserialize;
/// Convenient type alias for the query type.
///
/// Please refer to the [`DeserializeQuery`] trait for details.
///
/// [`DeserializeQuery`]: trait.DeserializeQuery.html
pub type Query<'de, T> = <T as DeserializeQuery<'de>>::Query;
/// A **data structure** that can be deserialized with a query.
///
/// The [`Query`] type is a `#[repr(transparent)]` wrapper automatically generated by
/// [the proc macro]. You can deserialize `Query<YourType>` first and then call `.into()`
/// to get `YourType`.
///
/// [`Query`]: trait.DeserializeQuery.html#associatedtype.Query
/// [the proc macro]: derive.DeserializeQuery.html
pub trait DeserializeQuery<'de>
where
Self: From<<Self as DeserializeQuery<'de>>::Query>,
Self::Query: Deserialize<'de> + Deref<Target = Self> + DerefMut,
{
/// The query type.
type Query;
}
// This module can only be used inside the generated code.
#[doc(hidden)]
pub mod __priv {
pub use serde;
extern crate alloc;
#[derive(Debug)]
pub struct Error {
field: &'static str,
prefix: &'static str,
message: alloc::borrow::Cow<'static, str>,
}
impl core::fmt::Display for Error {
fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
write!(
f,
"Query for field '{}' failed at '{}': {}",
self.field, self.prefix, self.message
)
}
}
impl Error {
pub fn owned(field: &'static str, prefix: &'static str, message: String) -> Self {
Error {
field,
prefix,
message: alloc::borrow::Cow::Owned(message),
}
}
pub fn borrowed(field: &'static str, prefix: &'static str, message: &'static str) -> Self {
Error {
field,
prefix,
message: alloc::borrow::Cow::Borrowed(message),
}
}
}
#[derive(Debug)]
pub struct Errors<'a> {
errors: &'a [Option<Error>],
}
impl<'a> core::fmt::Display for Errors<'a> {
fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
match self.error_count() {
0 => Ok(()),
1 => {
let error = self.errors().next().unwrap();
error.fmt(f)
}
_ => {
write!(f, "Queries failed for fields: ")?;
let mut following = false;
for error in self.errors() {
if following {
f.write_str(", ")?;
}
write!(f, "'{}'", error.field)?;
following = true;
}
f.write_str("\n")?;
let mut index = 1;
for error in self.errors() {
writeln!(f, " {}. {}", index, error)?;
index += 1;
}
Ok(())
}
}
}
}
impl<'a> Errors<'a> {
pub fn new(errors: &'a [Option<Error>]) -> Self {
Self { errors }
}
fn error_count(&self) -> usize {
self.errors
.iter()
.map(|opt| if opt.is_some() { 1 } else { 0 })
.sum()
}
fn errors(&self) -> impl Iterator<Item = &Error> {
self.errors.iter().flatten()
}
}
pub trait Container {
type Element;
fn empty() -> Self;
fn reserve(&mut self, additional: usize);
fn extend_one(&mut self, element: Self::Element);
}
impl<T> Container for alloc::vec::Vec<T> {
type Element = T;
fn empty() -> Self {
Self::new()
}
fn reserve(&mut self, additional: usize) {
self.reserve(additional);
}
fn extend_one(&mut self, element: Self::Element) {
self.push(element);
}
}
impl<T> Container for alloc::collections::VecDeque<T> {
type Element = T;
fn empty() -> Self {
Self::new()
}
fn reserve(&mut self, additional: usize) {
self.reserve(additional);
}
fn extend_one(&mut self, element: Self::Element) {
self.push_back(element);
}
}
impl<T: core::cmp::Ord> Container for alloc::collections::BTreeSet<T> {
type Element = T;
fn empty() -> Self {
Self::new()
}
fn reserve(&mut self, _additional: usize) {
// do nothing
}
fn extend_one(&mut self, element: Self::Element) {
self.insert(element);
}
}
impl<T: core::cmp::Eq + core::hash::Hash> Container for std::collections::HashSet<T> {
type Element = T;
fn empty() -> Self {
Self::new()
}
fn reserve(&mut self, additional: usize) {
self.reserve(additional);
}
fn extend_one(&mut self, element: Self::Element) {
self.insert(element);
}
}
}