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//! Utilities used to access and create Erlang maps.
use super::atom;
use crate::wrapper::map;
use crate::{Decoder, Encoder, Env, Error, NifResult, Term};
use std::ops::RangeInclusive;
#[inline]
pub fn map_new(env: Env) -> Term {
unsafe { Term::new(env, map::map_new(env.as_c_arg())) }
}
/// ## Map terms
impl<'a> Term<'a> {
/// Constructs a new, empty map term.
///
/// ### Elixir equivalent
/// ```elixir
/// %{}
/// ```
#[inline]
pub fn map_new(env: Env<'a>) -> Term<'a> {
map_new(env)
}
/// Construct a new map from two vectors
///
/// ### Elixir equivalent
/// ```elixir
/// keys = ["foo", "bar"]
/// values = [1, 2]
/// Enum.zip(keys, values) |> Map.new()
/// ```
#[inline]
pub fn map_from_arrays(
env: Env<'a>,
keys: &[impl Encoder],
values: &[impl Encoder],
) -> NifResult<Term<'a>> {
if keys.len() == values.len() {
let keys: Vec<_> = keys.iter().map(|k| k.encode(env).as_c_arg()).collect();
let values: Vec<_> = values.iter().map(|v| v.encode(env).as_c_arg()).collect();
unsafe {
map::make_map_from_arrays(env.as_c_arg(), &keys, &values)
.map_or_else(|| Err(Error::BadArg), |map| Ok(Term::new(env, map)))
}
} else {
Err(Error::BadArg)
}
}
/// Construct a new map from two vectors of terms.
///
/// It is identical to map_from_arrays, but requires the keys and values to
/// be encoded already - this is useful for constructing maps whose values
/// or keys are different Rust types, with the same performance as map_from_arrays.
pub fn map_from_term_arrays(
env: Env<'a>,
keys: &[Term<'a>],
values: &[Term<'a>],
) -> NifResult<Term<'a>> {
if keys.len() == values.len() {
let keys: Vec<_> = keys.iter().map(|k| k.as_c_arg()).collect();
let values: Vec<_> = values.iter().map(|v| v.as_c_arg()).collect();
unsafe {
map::make_map_from_arrays(env.as_c_arg(), &keys, &values)
.map_or_else(|| Err(Error::BadArg), |map| Ok(Term::new(env, map)))
}
} else {
Err(Error::BadArg)
}
}
/// Construct a new map from pairs of terms
///
/// It is similar to `map_from_arrays` but
/// receives only one vector with the pairs
/// of `(key, value)`.
///
/// ### Elixir equivalent
/// ```elixir
/// Map.new([{"foo", 1}, {"bar", 2}])
/// ```
#[inline]
pub fn map_from_pairs(
env: Env<'a>,
pairs: &[(impl Encoder, impl Encoder)],
) -> NifResult<Term<'a>> {
let (keys, values): (Vec<_>, Vec<_>) = pairs
.iter()
.map(|(k, v)| (k.encode(env).as_c_arg(), v.encode(env).as_c_arg()))
.unzip();
unsafe {
map::make_map_from_arrays(env.as_c_arg(), &keys, &values)
.map_or_else(|| Err(Error::BadArg), |map| Ok(Term::new(env, map)))
}
}
/// Gets the value corresponding to a key in a map term.
///
/// Returns Err(Error::BadArg) if the term is not a map or if
/// key doesn't exist in the map.
///
/// ### Elixir equivalent
/// ```elixir
/// Map.get(self_term, key)
/// ```
#[inline]
pub fn map_get(self, key: impl Encoder) -> NifResult<Term<'a>> {
let env = self.get_env();
match unsafe {
map::get_map_value(env.as_c_arg(), self.as_c_arg(), key.encode(env).as_c_arg())
} {
Some(value) => Ok(unsafe { Term::new(env, value) }),
None => Err(Error::BadArg),
}
}
/// Gets the size of a map term.
///
/// Returns Err(Error::BadArg) if the term is not a map.
///
/// ### Elixir equivalent
/// ```elixir
/// map_size(self_term)
/// ```
#[inline]
pub fn map_size(self) -> NifResult<usize> {
let env = self.get_env();
unsafe { map::get_map_size(env.as_c_arg(), self.as_c_arg()).ok_or(Error::BadArg) }
}
/// Makes a copy of the self map term and sets key to value.
/// If the value already exists, it is overwritten.
///
/// Returns Err(Error::BadArg) if the term is not a map.
///
/// ### Elixir equivalent
/// ```elixir
/// Map.put(self_term, key, value)
/// ```
#[inline]
pub fn map_put(self, key: impl Encoder, value: impl Encoder) -> NifResult<Term<'a>> {
let env = self.get_env();
match unsafe {
map::map_put(
env.as_c_arg(),
self.as_c_arg(),
key.encode(env).as_c_arg(),
value.encode(env).as_c_arg(),
)
} {
Some(inner) => Ok(unsafe { Term::new(env, inner) }),
None => Err(Error::BadArg),
}
}
/// Makes a copy of the self map term and removes key. If the key
/// doesn't exist, the original map is returned.
///
/// Returns Err(Error::BadArg) if the term is not a map.
///
/// ### Elixir equivalent
/// ```elixir
/// Map.delete(self_term, key)
/// ```
#[inline]
pub fn map_remove(self, key: impl Encoder) -> NifResult<Term<'a>> {
let env = self.get_env();
match unsafe {
map::map_remove(env.as_c_arg(), self.as_c_arg(), key.encode(env).as_c_arg())
} {
Some(inner) => Ok(unsafe { Term::new(env, inner) }),
None => Err(Error::BadArg),
}
}
/// Makes a copy of the self map term where key is set to value.
///
/// Returns Err(Error::BadArg) if the term is not a map of if key
/// doesn't exist.
#[inline]
pub fn map_update(self, key: impl Encoder, new_value: impl Encoder) -> NifResult<Term<'a>> {
let env = self.get_env();
match unsafe {
map::map_update(
env.as_c_arg(),
self.as_c_arg(),
key.encode(env).as_c_arg(),
new_value.encode(env).as_c_arg(),
)
} {
Some(inner) => Ok(unsafe { Term::new(env, inner) }),
None => Err(Error::BadArg),
}
}
}
struct SimpleMapIterator<'a> {
map: Term<'a>,
entry: map::MapIteratorEntry,
iter: Option<map::ErlNifMapIterator>,
last_key: Option<Term<'a>>,
done: bool,
}
impl<'a> SimpleMapIterator<'a> {
fn next(&mut self) -> Option<(Term<'a>, Term<'a>)> {
if self.done {
return None;
}
let iter = loop {
match self.iter.as_mut() {
None => {
match unsafe {
map::map_iterator_create(
self.map.get_env().as_c_arg(),
self.map.as_c_arg(),
self.entry,
)
} {
Some(iter) => {
self.iter = Some(iter);
continue;
}
None => {
self.done = true;
return None;
}
}
}
Some(iter) => {
break iter;
}
}
};
let env = self.map.get_env();
unsafe {
match map::map_iterator_get_pair(env.as_c_arg(), iter) {
Some((key, value)) => {
match self.entry {
map::MapIteratorEntry::First => {
map::map_iterator_next(env.as_c_arg(), iter);
}
map::MapIteratorEntry::Last => {
map::map_iterator_prev(env.as_c_arg(), iter);
}
}
let key = Term::new(env, key);
self.last_key = Some(key);
Some((key, Term::new(env, value)))
}
None => {
self.done = true;
None
}
}
}
}
}
impl Drop for SimpleMapIterator<'_> {
fn drop(&mut self) {
if let Some(iter) = self.iter.as_mut() {
unsafe {
map::map_iterator_destroy(self.map.get_env().as_c_arg(), iter);
}
}
}
}
pub struct MapIterator<'a> {
forward: SimpleMapIterator<'a>,
reverse: SimpleMapIterator<'a>,
}
impl<'a> MapIterator<'a> {
pub fn new(map: Term<'a>) -> Option<MapIterator<'a>> {
if map.is_map() {
Some(MapIterator {
forward: SimpleMapIterator {
map,
entry: map::MapIteratorEntry::First,
iter: None,
last_key: None,
done: false,
},
reverse: SimpleMapIterator {
map,
entry: map::MapIteratorEntry::Last,
iter: None,
last_key: None,
done: false,
},
})
} else {
None
}
}
}
impl<'a> Iterator for MapIterator<'a> {
type Item = (Term<'a>, Term<'a>);
fn next(&mut self) -> Option<Self::Item> {
self.forward.next().and_then(|(key, value)| {
if self.reverse.last_key == Some(key) {
self.forward.done = true;
self.reverse.done = true;
return None;
}
Some((key, value))
})
}
}
impl DoubleEndedIterator for MapIterator<'_> {
fn next_back(&mut self) -> Option<Self::Item> {
self.reverse.next().and_then(|(key, value)| {
if self.forward.last_key == Some(key) {
self.forward.done = true;
self.reverse.done = true;
return None;
}
Some((key, value))
})
}
}
impl<'a> Decoder<'a> for MapIterator<'a> {
fn decode(term: Term<'a>) -> NifResult<Self> {
match MapIterator::new(term) {
Some(iter) => Ok(iter),
None => Err(Error::BadArg),
}
}
}
impl<'a, T> Decoder<'a> for RangeInclusive<T>
where
T: Decoder<'a>,
{
fn decode(term: Term<'a>) -> NifResult<Self> {
let name = term.map_get(atom::__struct__())?;
match name.atom_to_string()?.as_ref() {
"Elixir.Range" => (),
_ => return Err(Error::BadArg),
}
let first = term.map_get(atom::first())?.decode::<T>()?;
let last = term.map_get(atom::last())?.decode::<T>()?;
if let Ok(step) = term.map_get(atom::step()) {
match step.decode::<i64>()? {
1 => (),
_ => return Err(Error::BadArg),
}
}
Ok(first..=last)
}
}