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use std::{collections::BTreeMap, convert::TryInto};
use tokio::sync::mpsc::{self, Sender};
use tokio::sync::oneshot;
pub mod model;
use model::Types;
enum Action {
Insert(String, Types),
Contains(String),
Get(String),
Len,
Keys,
Values,
Remove(String),
RemoveEntry(String),
}
/// `BTree` is where the informatio `Sender` is contained.
/// Its inner implementation has a tuple containing the action to be taken as well as a oneshot channel to receive data.
/// To start the `BTree` thread just execute `BTree::start(buffer_size: usize)`. If you `buffer_size` is too short
/// it may cause synchronization problems, so it should be well ajusted to your application needs.
pub struct BTree {
tx: Sender<(Action, tokio::sync::oneshot::Sender<Option<Types>>)>,
}
impl BTree {
/// `BTree::start(buffer_size: usize)` is the entrypoint to start using `BTree` methods.
/// It creates a thread containing the BTreeMap and keeps listening to entries.
pub fn start(buffer_size: usize) -> Self {
let (tx, mut rx) = mpsc::channel(buffer_size);
tokio::spawn(async move {
let mut btree: BTreeMap<String, Types> = BTreeMap::new();
loop {
if let Some((action, tx_o)) = rx.recv().await {
let tx_o: tokio::sync::oneshot::Sender<Option<Types>> = tx_o;
match action {
Action::Insert(k, v) => {
let insert = btree.insert(k, v);
if let Err(_) = tx_o.send(insert) {
println!("the receiver dropped, mpsc insert");
}
}
Action::Contains(k) => {
let contains = btree.contains_key(&k);
if let Err(_) = tx_o.send(Some(Types::Boolean(contains))) {
println!("the receiver dropped, mpsc contains k: {}", k);
}
}
Action::Get(k) => {
let get = btree.get(&k);
let get = if let Some(types) = get {
Some(types.to_owned())
} else {
None
};
if let Err(_) = tx_o.send(get) {
println!("the receiver dropped, mpsc get k: {}", k);
}
}
Action::Keys => {
let get = btree.keys();
let keys: Vec<Types> = get.map(|k| k.to_owned().into()).collect();
if let Err(_) = tx_o.send(Some(Types::Vector(keys))) {
println!("the receiver dropped, mpsc get keys");
}
}
Action::Values => {
let get = btree.values();
let values: Vec<Types> = get.map(|k| k.to_owned()).collect();
if let Err(_) = tx_o.send(Some(Types::Vector(values))) {
println!("the receiver dropped, mpsc get values");
}
}
Action::Len => {
let len = btree.len();
if let Err(_) = tx_o.send(Some(Types::UInteger(len))) {
println!("the receiver dropped, mpsc len");
}
}
Action::Remove(k) => {
let remove = btree.remove(&k);
if let Err(_) = tx_o.send(remove) {
println!("the receiver dropped, mpsc remove for key: {}", k);
}
}
Action::RemoveEntry(k) => {
let remove = btree.remove_entry(&k);
let key_val = if let Some((key, value)) = remove {
Some(Types::KeyValue(key, Box::new(value)))
} else {
None
};
if let Err(_) = tx_o.send(key_val) {
println!("the receiver dropped, mpsc remove_entry for key: {}", k);
}
}
}
}
}
});
Self { tx }
}
/// Method `insert` is equivalent to [`std::collection::BTreeMap insert`](https://doc.rust-lang.org/std/collections/struct.BTreeMap.html#method.insert),
/// it returns `None` if the key does not exist and it returns `Some(Types::_)` with the previous value,
/// if the key already exists.
pub async fn insert<V: Into<Types>>(&self, k: String, v: V) -> Result<Option<Types>, String> {
let v = v.into();
let tx = self.tx.clone();
let (tx_o, rx_o) = oneshot::channel();
let action = Action::Insert(k.clone(), v.clone());
let send = (action, tx_o);
tx.send(send)
.await
.map_err(|_| format!("receiver dropped, insert key {}, value {:?}", k, v))?;
rx_o.await
.map_err(|_| format!("insert failed {}, value {:?}", k, v))
}
/// Method `contains` is equivalent to [`std::collection::BTreeMap contains_key`](https://doc.rust-lang.org/std/collections/struct.BTreeMap.html#method.contains_key),
/// It checks if a key already exists in the `BTree`. If the key exists the return is `Ok(true)`,
/// if it doesn't exist it returns `Ok(false)`
pub async fn contains(&self, k: String) -> Result<bool, String> {
let tx = self.tx.clone();
let (tx_o, rx_o) = oneshot::channel();
let action = Action::Contains(k.clone());
let send = (action, tx_o);
tx.send(send)
.await
.map_err(|_| format!("receiver dropped, contains key {}", k))?;
match rx_o.await {
Ok(Some(Types::Boolean(true))) => Ok(true),
Err(e) => Err(format!("{:?}", e)),
_ => Ok(false),
}
}
/// Method `get` is equivalent to [`std::collection::BTreeMap get`](https://doc.rust-lang.org/std/collections/struct.BTreeMap.html#method.get),
/// It returns the value contained at the key passed as argument. If no key is found the return is `Ok(None)`,
/// else it returns `Ok(Some(Types::_))`.
pub async fn get(&self, k: String) -> Result<Option<Types>, String> {
let tx = self.tx.clone();
let (tx_o, rx_o) = oneshot::channel();
let action = Action::Get(k.clone());
let send = (action, tx_o);
tx.send(send)
.await
.map_err(|_| format!("receiver dropped, get key {}", k))?;
match rx_o.await {
Ok(types) => Ok(types),
Err(e) => Err(format!("get failed {} with error: {:?}", k, e)),
}
}
/// Method `len` is equivalent to [`std::collection::BTreeMap len`](https://doc.rust-lang.org/std/collections/struct.BTreeMap.html#method.len),
/// It returns the length of the btree as a usize.
pub async fn len(&self) -> Result<usize, String> {
let tx = self.tx.clone();
let (tx_o, rx_o) = oneshot::channel();
let action = Action::Len;
let send = (action, tx_o);
tx.send(send)
.await
.map_err(|_| format!("receiver dropped, len",))?;
match rx_o.await {
Ok(Some(Types::UInteger(len))) => Ok(len),
_ => Err(format!("len failed")),
}
}
/// Method `keys` is equivalent to [`std::collection::BTreeMap keys`](https://doc.rust-lang.org/std/collections/struct.BTreeMap.html#method.keys),
/// It returns a vector containing all the keys sorted.
/// For `BTree` the keys are always `Strings`.
pub async fn keys(&self) -> Result<Vec<String>, String> {
let tx = self.tx.clone();
let (tx_o, rx_o) = oneshot::channel();
let action = Action::Keys;
let send = (action, tx_o);
tx.send(send)
.await
.map_err(|_| format!("receiver dropped, get keys"))?;
match rx_o.await {
Ok(Some(Types::Vector(types))) => {
let vec = types
.into_iter()
.map(|k| k.try_into())
.collect::<Result<Vec<String>, String>>();
vec
}
Err(e) => Err(format!("get keys failed with error: {:?}", e)),
_ => Err(format!("get keys failed")),
}
}
/// Method `values` is equivalent to [`std::collection::BTreeMap values`](https://doc.rust-lang.org/std/collections/struct.BTreeMap.html#method.values),
/// It returns a vector containing all the values sorted by their respective keys order.
pub async fn values(&self) -> Result<Vec<Types>, String> {
let tx = self.tx.clone();
let (tx_o, rx_o) = oneshot::channel();
let action = Action::Values;
let send = (action, tx_o);
tx.send(send)
.await
.map_err(|_| format!("receiver dropped, get values"))?;
match rx_o.await {
Ok(Some(Types::Vector(types))) => Ok(types),
Err(e) => Err(format!("get values failed with error: {:?}", e)),
_ => Err(format!("get values failed")),
}
}
/// Method `remove` is equivalent to [`std::collection::BTreeMap remove`](https://doc.rust-lang.org/std/collections/struct.BTreeMap.html#method.remove),
/// It returns the value removed from the `BTree` for the key passed as argument. If no key is found the return is `Ok(None)`,
/// else it returns `Ok(Some(Types::_))`.
pub async fn remove(&self, k: String) -> Result<Option<Types>, String> {
let tx = self.tx.clone();
let (tx_o, rx_o) = oneshot::channel();
let action = Action::Remove(k.clone());
let send = (action, tx_o);
tx.send(send)
.await
.map_err(|_| format!("receiver dropped, remove key {}", k))?;
match rx_o.await {
Ok(types) => Ok(types),
Err(e) => Err(format!("remove failed {} with error: {:?}", k, e)),
}
}
/// Method `remove_entry` is equivalent to [`std::collection::BTreeMap remove_entry`](https://doc.rust-lang.org/std/collections/struct.BTreeMap.html#method.remove_entry),
/// It returns the key and value removed from the `BTree` for the key passed as argument as a `Option<Types::KeyValue(_,_)>`.
/// If no key is found the return is `Ok(None)`,
pub async fn remove_entry(&self, k: String) -> Result<Option<Types>, String> {
let tx = self.tx.clone();
let (tx_o, rx_o) = oneshot::channel();
let action = Action::RemoveEntry(k.clone());
let send = (action, tx_o);
tx.send(send)
.await
.map_err(|_| format!("receiver dropped, remove_entry key {}", k))?;
match rx_o.await {
Ok(types) => Ok(types),
Err(e) => Err(format!("remove_entry failed {} with error: {:?}", k, e)),
}
}
}