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use crate::{RedisError, Result};
use serde::de::DeserializeOwned;
use std::{
collections::HashMap,
fmt::{self, Display, Formatter, Write},
hash::{Hash, Hasher},
};
/// Generic Redis Object Model
///
/// This enum is a direct mapping to [`Redis serialization protocol`](https://redis.io/docs/latest/develop/reference/protocol-spec) (RESP)
#[derive(Default)]
pub enum Value {
/// [RESP Simple String](https://redis.io/docs/latest/develop/reference/protocol-spec/#simple-strings)
SimpleString(String),
/// [RESP Integer](https://redis.io/docs/latest/develop/reference/protocol-spec/#integers)
Integer(i64),
/// [RESP Double](https://redis.io/docs/latest/develop/reference/protocol-spec/#doubles)
///
/// Equality on this variant is total, as `Value` is `Eq` and usable as a
/// [`Value::Map`] key: all NaNs are equal to each other — so a `,nan` reply
/// equals itself — and `-0.0` equals `0.0`. Both depart from IEEE-754,
/// which has no reflexive NaN.
Double(f64),
/// [RESP Bulk String](https://redis.io/docs/latest/develop/reference/protocol-spec/#bulk-strings)
BulkString(Vec<u8>),
/// [RESP Boolean](https://redis.io/docs/latest/develop/reference/protocol-spec/#booleans)
Boolean(bool),
/// [RESP Array](https://redis.io/docs/latest/develop/reference/protocol-spec/#arrays)
Array(Vec<Value>),
/// [RESP Map](https://redis.io/docs/latest/develop/reference/protocol-spec/#maps)
Map(HashMap<Value, Value>),
/// [RESP Set](https://redis.io/docs/latest/develop/reference/protocol-spec/#sets)
Set(Vec<Value>),
/// [RESP Push](https://redis.io/docs/latest/develop/reference/protocol-spec/#pushes)
Push(Vec<Value>),
/// [RESP Error](https://redis.io/docs/latest/develop/reference/protocol-spec/#simple-errors)
Error(RedisError),
/// [RESP Null](https://redis.io/docs/latest/develop/reference/protocol-spec/#nulls)
#[default]
Null,
}
impl Value {
/// A [`Value`](crate::resp::Value) to user type conversion that consumes the input value.
///
/// # Errors
/// Any parsing error ([`ErrorKind::Client`](crate::ErrorKind::Client)) due to incompatibility between Value variant and taget type
#[inline]
pub fn into<T>(self) -> Result<T>
where
T: DeserializeOwned,
{
T::deserialize(&self)
}
}
/// Canonical bit pattern a [`Value::Double`] is compared and hashed on.
///
/// `Value` asserts `Eq`, which demands a reflexive equality, so the IEEE-754
/// rules are not usable as they stand: every NaN collapses onto a single
/// pattern, and the two zeros — equal under `==` — onto the positive one.
/// `Hash` and `PartialEq` share this function so they cannot drift apart.
fn canonical_double_bits(d: f64) -> u64 {
if d.is_nan() {
f64::NAN.to_bits()
} else if d == 0.0 {
0.0f64.to_bits()
} else {
d.to_bits()
}
}
impl Hash for Value {
fn hash<H: Hasher>(&self, state: &mut H) {
// A RESP3 map is `HashMap<Value, Value>`, so any variant can appear as a
// key and gets hashed — including Boolean/Array/Map/Set/Push reached from
// server data. Missing arms used to `unimplemented!()` and panic the
// decoding task, so every variant must hash. Mixing the discriminant in
// keeps values of different variants from colliding.
core::mem::discriminant(self).hash(state);
match self {
Value::SimpleString(s) => s.hash(state),
Value::Integer(i) => i.hash(state),
Value::Double(d) => canonical_double_bits(*d).hash(state),
Value::BulkString(bs) => bs.hash(state),
Value::Boolean(b) => b.hash(state),
Value::Array(v) | Value::Set(v) | Value::Push(v) => v.hash(state),
Value::Map(m) => {
// `HashMap` has no `Hash`; fold order-independently so equal maps
// hash equally regardless of iteration order.
let mut acc: u64 = 0;
for (k, val) in m {
let mut h = std::collections::hash_map::DefaultHasher::new();
k.hash(&mut h);
val.hash(&mut h);
acc = acc.wrapping_add(h.finish());
}
acc.hash(state);
}
Value::Error(e) => e.hash(state),
Value::Null => "_\r\n".hash(state),
}
}
}
impl PartialEq for Value {
fn eq(&self, other: &Self) -> bool {
match (self, other) {
(Self::SimpleString(l0), Self::SimpleString(r0)) => l0 == r0,
(Self::Integer(l0), Self::Integer(r0)) => l0 == r0,
(Self::Double(l0), Self::Double(r0)) => {
canonical_double_bits(*l0) == canonical_double_bits(*r0)
}
(Self::Boolean(l0), Self::Boolean(r0)) => l0 == r0,
(Self::BulkString(l0), Self::BulkString(r0)) => l0 == r0,
(Self::Array(l0), Self::Array(r0)) => l0 == r0,
(Self::Map(l0), Self::Map(r0)) => l0 == r0,
(Self::Set(l0), Self::Set(r0)) => l0 == r0,
(Self::Push(l0), Self::Push(r0)) => l0 == r0,
(Self::Error(l0), Self::Error(r0)) => l0 == r0,
_ => core::mem::discriminant(self) == core::mem::discriminant(other),
}
}
}
impl Eq for Value {}
impl Display for Value {
fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
match &self {
Value::SimpleString(s) => s.fmt(f),
Value::Integer(i) => i.fmt(f),
Value::Double(d) => d.fmt(f),
Value::BulkString(s) => String::from_utf8_lossy(s).fmt(f),
Value::Boolean(b) => b.fmt(f),
Value::Array(v) => {
f.write_char('[')?;
let mut first = true;
for value in v {
if !first {
f.write_str(", ")?;
}
first = false;
value.fmt(f)?;
}
f.write_char(']')
}
Value::Map(m) => {
f.write_char('{')?;
let mut first = true;
for (key, value) in m {
if !first {
f.write_str(", ")?;
}
first = false;
key.fmt(f)?;
f.write_str(": ")?;
value.fmt(f)?;
}
f.write_char('}')
}
Value::Set(v) => {
f.write_char('[')?;
let mut first = true;
for value in v {
if !first {
f.write_str(", ")?;
}
first = false;
value.fmt(f)?;
}
f.write_char(']')
}
Value::Push(v) => {
f.write_char('[')?;
let mut first = true;
for value in v {
if !first {
f.write_str(", ")?;
}
first = false;
value.fmt(f)?;
}
f.write_char(']')
}
Value::Error(e) => e.fmt(f),
Value::Null => f.write_str("Nil"),
}
}
}
impl fmt::Debug for Value {
fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
match self {
Self::SimpleString(arg0) => f.debug_tuple("SimpleString").field(arg0).finish(),
Self::Integer(arg0) => f.debug_tuple("Integer").field(arg0).finish(),
Self::Double(arg0) => f.debug_tuple("Double").field(arg0).finish(),
Self::BulkString(arg0) => f
.debug_tuple("BulkString")
.field(&String::from_utf8_lossy(arg0).into_owned())
.finish(),
Self::Boolean(arg0) => f.debug_tuple("Boolean").field(arg0).finish(),
Self::Array(arg0) => f.debug_tuple("Array").field(arg0).finish(),
Self::Map(arg0) => f.debug_tuple("Map").field(arg0).finish(),
Self::Set(arg0) => f.debug_tuple("Set").field(arg0).finish(),
Self::Push(arg0) => f.debug_tuple("Push").field(arg0).finish(),
Self::Error(arg0) => f.debug_tuple("Error").field(arg0).finish(),
Self::Null => write!(f, "Nil"),
}
}
}