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//! A YAML mapping and its iterator types.
use crate::Value;
use indexmap::IndexMap;
use serde::{Deserialize, Deserializer, Serialize};
use std::cmp::Ordering;
use std::collections::hash_map::DefaultHasher;
use std::fmt;
use std::hash::{Hash, Hasher};
use std::iter::FromIterator;
use std::ops::{Index, IndexMut};
/// A YAML mapping in which the keys and values are both `serde_yaml::Value`.
#[derive(Clone, Debug, Default, Eq, PartialEq)]
pub struct Mapping {
map: IndexMap<Value, Value>,
}
impl Mapping {
/// Creates an empty YAML map.
#[inline]
pub fn new() -> Self {
Self::default()
}
/// Creates an empty YAML map with the given initial capacity.
#[inline]
pub fn with_capacity(capacity: usize) -> Self {
Mapping {
map: IndexMap::with_capacity(capacity),
}
}
/// Reserves capacity for at least `additional` more elements to be inserted
/// into the map. The map may reserve more space to avoid frequent
/// allocations.
///
/// # Panics
///
/// Panics if the new allocation size overflows `usize`.
#[inline]
pub fn reserve(&mut self, additional: usize) {
self.map.reserve(additional);
}
/// Shrinks the capacity of the map as much as possible. It will drop down
/// as much as possible while maintaining the internal rules and possibly
/// leaving some space in accordance with the resize policy.
#[inline]
pub fn shrink_to_fit(&mut self) {
self.map.shrink_to_fit();
}
/// Inserts a key-value pair into the map. If the key already existed, the
/// old value is returned.
#[inline]
pub fn insert(&mut self, k: Value, v: Value) -> Option<Value> {
self.map.insert(k, v)
}
/// Checks if the map contains the given key.
#[inline]
pub fn contains_key(&self, k: &Value) -> bool {
self.map.contains_key(k)
}
/// Returns the value corresponding to the key in the map.
#[inline]
pub fn get(&self, k: &Value) -> Option<&Value> {
self.map.get(k)
}
/// Returns the mutable reference corresponding to the key in the map.
#[inline]
pub fn get_mut(&mut self, k: &Value) -> Option<&mut Value> {
self.map.get_mut(k)
}
/// Gets the given key’s corresponding entry in the map for insertion and/or
/// in-place manipulation.
#[inline]
pub fn entry(&mut self, k: Value) -> Entry {
match self.map.entry(k) {
indexmap::map::Entry::Occupied(occupied) => Entry::Occupied(OccupiedEntry { occupied }),
indexmap::map::Entry::Vacant(vacant) => Entry::Vacant(VacantEntry { vacant }),
}
}
/// Removes and returns the value corresponding to the key from the map.
#[inline]
pub fn remove(&mut self, k: &Value) -> Option<Value> {
self.map.remove(k)
}
/// Returns the maximum number of key-value pairs the map can hold without
/// reallocating.
#[inline]
pub fn capacity(&self) -> usize {
self.map.capacity()
}
/// Returns the number of key-value pairs in the map.
#[inline]
pub fn len(&self) -> usize {
self.map.len()
}
/// Returns whether the map is currently empty.
#[inline]
pub fn is_empty(&self) -> bool {
self.map.is_empty()
}
/// Clears the map of all key-value pairs.
#[inline]
pub fn clear(&mut self) {
self.map.clear();
}
/// Returns a double-ended iterator visiting all key-value pairs in order of
/// insertion. Iterator element type is `(&'a Value, &'a Value)`.
#[inline]
pub fn iter(&self) -> Iter {
Iter {
iter: self.map.iter(),
}
}
/// Returns a double-ended iterator visiting all key-value pairs in order of
/// insertion. Iterator element type is `(&'a Value, &'a mut ValuE)`.
#[inline]
pub fn iter_mut(&mut self) -> IterMut {
IterMut {
iter: self.map.iter_mut(),
}
}
}
#[allow(clippy::derive_hash_xor_eq)]
impl Hash for Mapping {
fn hash<H: Hasher>(&self, state: &mut H) {
// Hash the kv pairs in a way that is not sensitive to their order.
let mut xor = 0;
for (k, v) in self {
let mut hasher = DefaultHasher::new();
k.hash(&mut hasher);
v.hash(&mut hasher);
xor ^= hasher.finish();
}
xor.hash(state);
}
}
impl PartialOrd for Mapping {
fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
let mut self_entries = Vec::from_iter(self);
let mut other_entries = Vec::from_iter(other);
// Sort in an arbitrary order that is consistent with Value's PartialOrd
// impl.
fn total_cmp(a: &Value, b: &Value) -> Ordering {
match (a, b) {
(Value::Null, Value::Null) => Ordering::Equal,
(Value::Null, _) => Ordering::Less,
(_, Value::Null) => Ordering::Greater,
(Value::Bool(a), Value::Bool(b)) => a.cmp(b),
(Value::Bool(_), _) => Ordering::Less,
(_, Value::Bool(_)) => Ordering::Greater,
(Value::Number(a), Value::Number(b)) => a.total_cmp(b),
(Value::Number(_), _) => Ordering::Less,
(_, Value::Number(_)) => Ordering::Greater,
(Value::String(a), Value::String(b)) => a.cmp(b),
(Value::String(_), _) => Ordering::Less,
(_, Value::String(_)) => Ordering::Greater,
(Value::Sequence(a), Value::Sequence(b)) => iter_cmp_by(a, b, total_cmp),
(Value::Sequence(_), _) => Ordering::Less,
(_, Value::Sequence(_)) => Ordering::Greater,
(Value::Mapping(a), Value::Mapping(b)) => {
iter_cmp_by(a, b, |(ak, av), (bk, bv)| {
total_cmp(ak, bk).then_with(|| total_cmp(av, bv))
})
}
}
}
fn iter_cmp_by<I, F>(this: I, other: I, mut cmp: F) -> Ordering
where
I: IntoIterator,
F: FnMut(I::Item, I::Item) -> Ordering,
{
let mut this = this.into_iter();
let mut other = other.into_iter();
loop {
let x = match this.next() {
None => {
if other.next().is_none() {
return Ordering::Equal;
} else {
return Ordering::Less;
}
}
Some(val) => val,
};
let y = match other.next() {
None => return Ordering::Greater,
Some(val) => val,
};
match cmp(x, y) {
Ordering::Equal => {}
non_eq => return non_eq,
}
}
}
// While sorting by map key, we get to assume that no two keys are
// equal, otherwise they wouldn't both be in the map. This is not a safe
// assumption outside of this situation.
let total_cmp = |&(a, _): &_, &(b, _): &_| total_cmp(a, b);
self_entries.sort_by(total_cmp);
other_entries.sort_by(total_cmp);
self_entries.partial_cmp(&other_entries)
}
}
impl<'a> Index<&'a Value> for Mapping {
type Output = Value;
#[inline]
fn index(&self, index: &'a Value) -> &Value {
self.map.index(index)
}
}
impl<'a> IndexMut<&'a Value> for Mapping {
#[inline]
fn index_mut(&mut self, index: &'a Value) -> &mut Value {
self.map.index_mut(index)
}
}
impl Extend<(Value, Value)> for Mapping {
#[inline]
fn extend<I: IntoIterator<Item = (Value, Value)>>(&mut self, iter: I) {
self.map.extend(iter);
}
}
impl FromIterator<(Value, Value)> for Mapping {
#[inline]
fn from_iter<I: IntoIterator<Item = (Value, Value)>>(iter: I) -> Self {
Mapping {
map: IndexMap::from_iter(iter),
}
}
}
macro_rules! delegate_iterator {
(($name:ident $($generics:tt)*) => $item:ty) => {
impl $($generics)* Iterator for $name $($generics)* {
type Item = $item;
#[inline]
fn next(&mut self) -> Option<Self::Item> {
self.iter.next()
}
#[inline]
fn size_hint(&self) -> (usize, Option<usize>) {
self.iter.size_hint()
}
}
impl $($generics)* ExactSizeIterator for $name $($generics)* {
#[inline]
fn len(&self) -> usize {
self.iter.len()
}
}
}
}
/// Iterator over `&serde_yaml::Mapping`.
pub struct Iter<'a> {
iter: indexmap::map::Iter<'a, Value, Value>,
}
delegate_iterator!((Iter<'a>) => (&'a Value, &'a Value));
impl<'a> IntoIterator for &'a Mapping {
type Item = (&'a Value, &'a Value);
type IntoIter = Iter<'a>;
#[inline]
fn into_iter(self) -> Self::IntoIter {
Iter {
iter: self.map.iter(),
}
}
}
/// Iterator over `&mut serde_yaml::Mapping`.
pub struct IterMut<'a> {
iter: indexmap::map::IterMut<'a, Value, Value>,
}
delegate_iterator!((IterMut<'a>) => (&'a Value, &'a mut Value));
impl<'a> IntoIterator for &'a mut Mapping {
type Item = (&'a Value, &'a mut Value);
type IntoIter = IterMut<'a>;
#[inline]
fn into_iter(self) -> Self::IntoIter {
IterMut {
iter: self.map.iter_mut(),
}
}
}
/// Iterator over `serde_yaml::Mapping` by value.
pub struct IntoIter {
iter: indexmap::map::IntoIter<Value, Value>,
}
delegate_iterator!((IntoIter) => (Value, Value));
impl IntoIterator for Mapping {
type Item = (Value, Value);
type IntoIter = IntoIter;
#[inline]
fn into_iter(self) -> Self::IntoIter {
IntoIter {
iter: self.map.into_iter(),
}
}
}
/// Entry for an existing key-value pair or a vacant location to insert one.
pub enum Entry<'a> {
/// Existing slot with equivalent key.
Occupied(OccupiedEntry<'a>),
/// Vacant slot (no equivalent key in the map).
Vacant(VacantEntry<'a>),
}
/// A view into an occupied entry in a [`Mapping`]. It is part of the [`Entry`]
/// enum.
pub struct OccupiedEntry<'a> {
occupied: indexmap::map::OccupiedEntry<'a, Value, Value>,
}
/// A view into a vacant entry in a [`Mapping`]. It is part of the [`Entry`]
/// enum.
pub struct VacantEntry<'a> {
vacant: indexmap::map::VacantEntry<'a, Value, Value>,
}
impl<'a> Entry<'a> {
/// Returns a reference to this entry's key.
pub fn key(&self) -> &Value {
match self {
Entry::Vacant(e) => e.key(),
Entry::Occupied(e) => e.key(),
}
}
/// Ensures a value is in the entry by inserting the default if empty, and
/// returns a mutable reference to the value in the entry.
pub fn or_insert(self, default: Value) -> &'a mut Value {
match self {
Entry::Vacant(entry) => entry.insert(default),
Entry::Occupied(entry) => entry.into_mut(),
}
}
/// Ensures a value is in the entry by inserting the result of the default
/// function if empty, and returns a mutable reference to the value in the
/// entry.
pub fn or_insert_with<F>(self, default: F) -> &'a mut Value
where
F: FnOnce() -> Value,
{
match self {
Entry::Vacant(entry) => entry.insert(default()),
Entry::Occupied(entry) => entry.into_mut(),
}
}
/// Provides in-place mutable access to an occupied entry before any
/// potential inserts into the map.
pub fn and_modify<F>(self, f: F) -> Self
where
F: FnOnce(&mut Value),
{
match self {
Entry::Occupied(mut entry) => {
f(entry.get_mut());
Entry::Occupied(entry)
}
Entry::Vacant(entry) => Entry::Vacant(entry),
}
}
}
impl<'a> OccupiedEntry<'a> {
/// Gets a reference to the key in the entry.
#[inline]
pub fn key(&self) -> &Value {
self.occupied.key()
}
/// Gets a reference to the value in the entry.
#[inline]
pub fn get(&self) -> &Value {
self.occupied.get()
}
/// Gets a mutable reference to the value in the entry.
#[inline]
pub fn get_mut(&mut self) -> &mut Value {
self.occupied.get_mut()
}
/// Converts the entry into a mutable reference to its value.
#[inline]
pub fn into_mut(self) -> &'a mut Value {
self.occupied.into_mut()
}
/// Sets the value of the entry with the `OccupiedEntry`'s key, and returns
/// the entry's old value.
#[inline]
pub fn insert(&mut self, value: Value) -> Value {
self.occupied.insert(value)
}
/// Takes the value of the entry out of the map, and returns it.
#[inline]
pub fn remove(self) -> Value {
self.occupied.swap_remove()
}
}
impl<'a> VacantEntry<'a> {
/// Gets a reference to the key that would be used when inserting a value
/// through the VacantEntry.
#[inline]
pub fn key(&self) -> &Value {
self.vacant.key()
}
/// Sets the value of the entry with the VacantEntry's key, and returns a
/// mutable reference to it.
#[inline]
pub fn insert(self, value: Value) -> &'a mut Value {
self.vacant.insert(value)
}
}
impl Serialize for Mapping {
#[inline]
fn serialize<S: serde::Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error> {
use serde::ser::SerializeMap;
let mut map_serializer = serializer.serialize_map(Some(self.len()))?;
for (k, v) in self {
map_serializer.serialize_entry(k, v)?;
}
map_serializer.end()
}
}
impl<'de> Deserialize<'de> for Mapping {
fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
where
D: Deserializer<'de>,
{
struct Visitor;
impl<'de> serde::de::Visitor<'de> for Visitor {
type Value = Mapping;
fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
formatter.write_str("a YAML mapping")
}
#[inline]
fn visit_unit<E>(self) -> Result<Self::Value, E>
where
E: serde::de::Error,
{
Ok(Mapping::new())
}
#[inline]
fn visit_map<V>(self, mut visitor: V) -> Result<Self::Value, V::Error>
where
V: serde::de::MapAccess<'de>,
{
let mut values = Mapping::new();
while let Some((k, v)) = visitor.next_entry()? {
values.insert(k, v);
}
Ok(values)
}
}
deserializer.deserialize_map(Visitor)
}
}