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Implement TryInto for Value #947

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1 change: 1 addition & 0 deletions src/value/mod.rs
Original file line number Diff line number Diff line change
Expand Up @@ -880,6 +880,7 @@ mod from;
mod index;
mod partial_eq;
mod ser;
mod try_into;

/// Convert a `T` into `serde_json::Value` which is an enum that can represent
/// any valid JSON data.
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163 changes: 163 additions & 0 deletions src/value/try_into.rs
Original file line number Diff line number Diff line change
@@ -0,0 +1,163 @@
use core::convert::TryInto;
use alloc::string::String;
use alloc::vec::Vec;
use crate::map::Map;
use crate::error::Error;
use super::Value;

impl TryInto<String> for Value {
type Error = Error;

fn try_into(self) -> Result<String, Error> {
match self {
Value::String(s) => Ok(s),
_ => Err(<Error as serde::de::Error>::custom("value is not a string")),
}
}
}

impl<'a> TryInto<&'a String> for &'a Value {
type Error = Error;

fn try_into(self) -> Result<&'a String, Error> {
match self {
Value::String(s) => Ok(s),
_ => Err(<Error as serde::de::Error>::custom("value is not a string")),
}
}
}

impl<'a> TryInto<&'a str> for &'a Value {
type Error = Error;

fn try_into(self) -> Result<&'a str, Error> {
self.as_str().ok_or_else(|| <Error as serde::de::Error>::custom("value is not a string"))
}
}

impl TryInto<f64> for Value {
type Error = Error;

fn try_into(self) -> Result<f64, Error> {
self.as_f64().ok_or_else(|| <Error as serde::de::Error>::custom("value is not an f64"))
}
}


impl TryInto<f64> for &Value {
type Error = Error;

fn try_into(self) -> Result<f64, Error> {
self.as_f64().ok_or_else(|| <Error as serde::de::Error>::custom("value is not an f64"))
}
}

impl TryInto<i64> for Value {
type Error = Error;

fn try_into(self) -> Result<i64, Error> {
self.as_i64().ok_or_else(|| <Error as serde::de::Error>::custom("value is not an i64"))
}
}

impl TryInto<i64> for &Value {
type Error = Error;

fn try_into(self) -> Result<i64, Error> {
self.as_i64().ok_or_else(|| <Error as serde::de::Error>::custom("value is not an i64"))
}
}

impl TryInto<u64> for Value {
type Error = Error;

fn try_into(self) -> Result<u64, Error> {
self.as_u64().ok_or_else(|| <Error as serde::de::Error>::custom("value is not an u64"))
}
}

impl TryInto<u64> for &Value {
type Error = Error;

fn try_into(self) -> Result<u64, Error> {
self.as_u64().ok_or_else(|| <Error as serde::de::Error>::custom("value is not an u64"))
}
}

impl TryInto<bool> for Value {
type Error = Error;

fn try_into(self) -> Result<bool, Error> {
self.as_bool().ok_or_else(|| <Error as serde::de::Error>::custom("value is not a bool"))
}
}

impl TryInto<bool> for &Value {
type Error = Error;

fn try_into(self) -> Result<bool, Error> {
self.as_bool().ok_or_else(|| <Error as serde::de::Error>::custom("value is not a bool"))
}
}

impl<'a> TryInto<&'a Vec<Value>> for &'a Value {
type Error = Error;

fn try_into(self) -> Result<&'a Vec<Value>, Error> {
self.as_array().ok_or_else(|| <Error as serde::de::Error>::custom("value is not an array"))
}
}

impl<'a> TryInto<&'a [Value]> for &'a Value {
type Error = Error;

fn try_into(self) -> Result<&'a [Value], Error> {
self.as_array().map(|v| v.as_slice()).ok_or_else(|| <Error as serde::de::Error>::custom("value is not an array"))
}
}

impl TryInto<Vec<Value>> for Value {
type Error = Error;

fn try_into(self) -> Result<Vec<Value>, Error> {
match self {
Value::Array(a) => Ok(a),
_ => Err(<Error as serde::de::Error>::custom("value is not an array")),
}
}
}

impl TryInto<Map<String, Value>> for Value {
type Error = Error;

fn try_into(self) -> Result<Map<String, Value>, Error> {
match self {
Value::Object(o) => Ok(o),
_ => Err(<Error as serde::de::Error>::custom("value is not an object")),
}
}
}

impl<'a> TryInto<&'a Map<String, Value>> for &'a Value {
type Error = Error;

fn try_into(self) -> Result<&'a Map<String, Value>, Error> {
self.as_object().ok_or_else(|| <Error as serde::de::Error>::custom("value is not an object"))
}
}

impl TryInto<()> for Value {
type Error = Error;

fn try_into(self) -> Result<(), Error> {
self.as_null().ok_or_else(|| <Error as serde::de::Error>::custom("value is not a null"))
}
}

impl TryInto<()> for &Value {
type Error = Error;

fn try_into(self) -> Result<(), Error> {
self.as_null().ok_or_else(|| <Error as serde::de::Error>::custom("value is not a null"))
}
}
87 changes: 87 additions & 0 deletions tests/test.rs
Original file line number Diff line number Diff line change
Expand Up @@ -2060,6 +2060,93 @@ fn test_partialeq_bool() {
assert_ne!(v, 0);
}

#[test]
fn test_tryinto_string() {
use std::convert::TryInto;
let v = to_value("42").unwrap();
let s: &String = (&v).try_into().unwrap();
assert_eq!(s, "42");
let s: &str = (&v).try_into().unwrap();
assert_eq!(s, "42");
let s: String = v.clone().try_into().unwrap();
assert_eq!(s, "42");
}

#[test]
fn test_tryinto_number() {
use std::convert::TryInto;
let v = to_value(42).unwrap();
let n: u64 = (&v).try_into().unwrap();
assert_eq!(n, 42);
let n: i64 = (&v).try_into().unwrap();
assert_eq!(n, 42);
let n: f64 = (&v).try_into().unwrap();
assert_eq!(n, 42.0);
let n: u64 = v.clone().try_into().unwrap();
assert_eq!(n, 42);
let n: i64 = v.clone().try_into().unwrap();
assert_eq!(n, 42);
let n: f64 = v.clone().try_into().unwrap();
assert_eq!(n, 42.0);
}

#[test]
fn test_tryinto_bool() {
use std::convert::TryInto;
let v = to_value(true).unwrap();
let b: bool = (&v).try_into().unwrap();
assert_eq!(b, true);
let b: bool = v.try_into().unwrap();
assert_eq!(b, true);

let v = to_value(false).unwrap();
let b: bool = (&v).try_into().unwrap();
assert_eq!(b, false);
let b: bool = v.try_into().unwrap();
assert_eq!(b, false);
}

#[test]
fn test_tryinto_null() {
use std::convert::TryInto;
let v = to_value(()).unwrap();
let n: () = v.try_into().unwrap();
assert_eq!(n, ());
}

#[test]
fn test_tryinto_array() {
use std::convert::TryInto;

let v = json!([1, 2, 3]);
let a: &Vec<Value> = (&v).try_into().unwrap();
assert_eq!(a, &vec![1, 2, 3]);
let a: &[Value] = (&v).try_into().unwrap();
assert_eq!(a, vec![1, 2, 3]);
let a: Vec<Value> = v.try_into().unwrap();
assert_eq!(a, vec![1, 2, 3]);

let v = json!([1, 2.0, "foo", { "bar": "baz"}, null, false]);
let _a: &Vec<Value> = (&v).try_into().unwrap();
let _a: &[Value] = (&v).try_into().unwrap();
let _a: Vec<Value> = v.try_into().unwrap();
}

#[test]
fn test_tryinto_object() {
use std::convert::TryInto;
use serde_json::map::Map;

let mut map = Map::new();
map.insert("foo".to_string(), json!("bar"));

let v = json!({"foo": "bar"});
let m: &Map<String, Value> = (&v).try_into().unwrap();
assert_eq!(m, &map);
let m: Map<String, Value> = v.try_into().unwrap();
assert_eq!(m, map);
}

struct FailReader(io::ErrorKind);

impl io::Read for FailReader {
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