MeiliSearch/milli/src/fields_ids_map.rs

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use std::collections::BTreeMap;
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use serde::{Deserialize, Serialize};
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use crate::FieldId;
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#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct FieldsIdsMap {
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names_ids: BTreeMap<String, FieldId>,
ids_names: BTreeMap<FieldId, String>,
next_id: Option<FieldId>,
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}
impl FieldsIdsMap {
pub fn new() -> FieldsIdsMap {
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FieldsIdsMap { names_ids: BTreeMap::new(), ids_names: BTreeMap::new(), next_id: Some(0) }
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}
/// Returns the number of fields ids in the map.
pub fn len(&self) -> usize {
self.names_ids.len()
}
/// Returns `true` if the map is empty.
pub fn is_empty(&self) -> bool {
self.names_ids.is_empty()
}
/// Returns the field id related to a field name, it will create a new field id if the
/// name is not already known. Returns `None` if the maximum field id as been reached.
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pub fn insert(&mut self, name: &str) -> Option<FieldId> {
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match self.names_ids.get(name) {
Some(id) => Some(*id),
None => {
let id = self.next_id?;
self.next_id = id.checked_add(1);
self.names_ids.insert(name.to_owned(), id);
self.ids_names.insert(id, name.to_owned());
Some(id)
}
}
}
/// Get the id of a field based on its name.
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pub fn id(&self, name: &str) -> Option<FieldId> {
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self.names_ids.get(name).copied()
}
/// Get the name of a field based on its id.
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pub fn name(&self, id: FieldId) -> Option<&str> {
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self.ids_names.get(&id).map(String::as_str)
}
/// Remove a field name and id based on its name.
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pub fn remove(&mut self, name: &str) -> Option<FieldId> {
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match self.names_ids.remove(name) {
Some(id) => self.ids_names.remove_entry(&id).map(|(id, _)| id),
None => None,
}
}
/// Iterate over the ids and names in the ids order.
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pub fn iter(&self) -> impl Iterator<Item = (FieldId, &str)> {
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self.ids_names.iter().map(|(id, name)| (*id, name.as_str()))
}
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/// Iterate over the ids in the order of the ids.
pub fn ids(&'_ self) -> impl Iterator<Item = FieldId> + '_ {
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self.ids_names.keys().copied()
}
/// Iterate over the names in the order of the ids.
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pub fn names(&self) -> impl Iterator<Item = &str> {
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self.ids_names.values().map(AsRef::as_ref)
}
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}
impl Default for FieldsIdsMap {
fn default() -> FieldsIdsMap {
FieldsIdsMap::new()
}
}
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#[cfg(test)]
mod tests {
use super::*;
#[test]
fn fields_ids_map() {
let mut map = FieldsIdsMap::new();
assert_eq!(map.insert("id"), Some(0));
assert_eq!(map.insert("title"), Some(1));
assert_eq!(map.insert("description"), Some(2));
assert_eq!(map.insert("id"), Some(0));
assert_eq!(map.insert("title"), Some(1));
assert_eq!(map.insert("description"), Some(2));
assert_eq!(map.id("id"), Some(0));
assert_eq!(map.id("title"), Some(1));
assert_eq!(map.id("description"), Some(2));
assert_eq!(map.id("date"), None);
assert_eq!(map.len(), 3);
assert_eq!(map.name(0), Some("id"));
assert_eq!(map.name(1), Some("title"));
assert_eq!(map.name(2), Some("description"));
assert_eq!(map.name(4), None);
assert_eq!(map.remove("title"), Some(1));
assert_eq!(map.id("title"), None);
assert_eq!(map.insert("title"), Some(3));
assert_eq!(map.len(), 3);
let mut iter = map.iter();
assert_eq!(iter.next(), Some((0, "id")));
assert_eq!(iter.next(), Some((2, "description")));
assert_eq!(iter.next(), Some((3, "title")));
assert_eq!(iter.next(), None);
}
}