native_db_32bit/transaction/query/scan/secondary_scan.rs
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use crate::db_type::{unwrap_item, DatabaseInnerKeyValue, DatabaseInnerKeyValueRange, Input};
use crate::InnerKeyValue;
use redb;
use std::marker::PhantomData;
use std::ops::RangeBounds;
/// Scan values from the database by secondary key.
pub struct SecondaryScan<PrimaryTable, SecondaryTable, T: Input>
where
PrimaryTable: redb::ReadableTable<DatabaseInnerKeyValue, &'static [u8]>,
SecondaryTable: redb::ReadableTable<DatabaseInnerKeyValue, DatabaseInnerKeyValue>,
{
pub(crate) primary_table: PrimaryTable,
pub(crate) secondary_table: SecondaryTable,
pub(crate) _marker: PhantomData<T>,
}
impl<PrimaryTable, SecondaryTable, T: Input> SecondaryScan<PrimaryTable, SecondaryTable, T>
where
PrimaryTable: redb::ReadableTable<DatabaseInnerKeyValue, &'static [u8]>,
SecondaryTable: redb::ReadableTable<DatabaseInnerKeyValue, DatabaseInnerKeyValue>,
{
pub(crate) fn new(primary_table: PrimaryTable, secondary_table: SecondaryTable) -> Self {
Self {
primary_table,
secondary_table,
_marker: PhantomData::default(),
}
}
/// Iterate over all values by secondary key.
///
/// If the secondary key is [`optional`](struct.DatabaseBuilder.html#optional) you will
/// get all values that have the secondary key set.
///
/// Anatomy of a secondary key it is a `enum` with the following structure: `<table_name>Key::<name>`.
///
/// # Example
/// ```rust
/// use native_db::*;
/// use native_model::{native_model, Model};
/// use serde::{Deserialize, Serialize};
///
/// #[derive(Serialize, Deserialize)]
/// #[native_model(id=1, version=1)]
/// #[native_db]
/// struct Data {
/// #[primary_key]
/// id: u64,
/// #[secondary_key(optional)]
/// name: Option<String>,
/// }
///
/// fn main() -> Result<(), db_type::Error> {
/// let mut builder = DatabaseBuilder::new();
/// builder.define::<Data>()?;
/// let db = builder.create_in_memory()?;
///
/// // Open a read transaction
/// let r = db.r_transaction()?;
///
/// // Get only values that have the secondary key set (name is not None)
/// let _values: Vec<Data> = r.scan().secondary(DataKey::name)?.all().collect();
/// Ok(())
/// }
/// ```
pub fn all(&self) -> SecondaryScanIterator<PrimaryTable, T> {
let range = self
.secondary_table
.range::<DatabaseInnerKeyValue>(..)
.unwrap();
SecondaryScanIterator {
primary_table: &self.primary_table,
range,
_marker: PhantomData::default(),
}
}
/// Iterate over all values by secondary key.
///
/// Anatomy of a secondary key it is a `enum` with the following structure: `<table_name>Key::<name>`.
///
/// # Example
/// ```rust
/// use native_db::*;
/// use native_model::{native_model, Model};
/// use serde::{Deserialize, Serialize};
///
/// #[derive(Serialize, Deserialize)]
/// #[native_model(id=1, version=1)]
/// #[native_db]
/// struct Data {
/// #[primary_key]
/// id: u64,
/// #[secondary_key]
/// name: String,
/// }
///
/// fn main() -> Result<(), db_type::Error> {
/// let mut builder = DatabaseBuilder::new();
/// builder.define::<Data>()?;
/// let db = builder.create_in_memory()?;
///
/// // Open a read transaction
/// let r = db.r_transaction()?;
///
/// // Get only values that have the secondary key name from C to the end
/// let _values: Vec<Data> = r.scan().secondary(DataKey::name)?.range("C"..).collect();
/// Ok(())
/// }
/// ```
pub fn range<TR: InnerKeyValue, R: RangeBounds<TR>>(
&self,
range: R,
) -> SecondaryScanIterator<PrimaryTable, T> {
let database_inner_key_value_range = DatabaseInnerKeyValueRange::new(range);
let range = self
.secondary_table
.range::<DatabaseInnerKeyValue>(database_inner_key_value_range)
.unwrap();
SecondaryScanIterator {
primary_table: &self.primary_table,
range,
_marker: PhantomData::default(),
}
}
/// Iterate over all values by secondary key.
///
/// Anatomy of a secondary key it is a `enum` with the following structure: `<table_name>Key::<name>`.
///
/// # Example
/// ```rust
/// use native_db::*;
/// use native_model::{native_model, Model};
/// use serde::{Deserialize, Serialize};
///
/// #[derive(Serialize, Deserialize)]
/// #[native_model(id=1, version=1)]
/// #[native_db]
/// struct Data {
/// #[primary_key]
/// id: u64,
/// #[secondary_key]
/// name: String,
/// }
///
/// fn main() -> Result<(), db_type::Error> {
/// let mut builder = DatabaseBuilder::new();
/// builder.define::<Data>()?;
/// let db = builder.create_in_memory()?;
///
/// // Open a read transaction
/// let r = db.r_transaction()?;
///
/// // Get only values that have the secondary key name starting with "hello"
/// let _values: Vec<Data> = r.scan().secondary(DataKey::name)?.start_with("hello").collect();
/// Ok(())
/// }
/// ```
pub fn start_with<'a>(
&'a self,
start_with: impl InnerKeyValue + 'a,
) -> SecondaryScanIteratorStartWith<'a, PrimaryTable, T> {
let start_with = start_with.database_inner_key_value();
let range = self
.secondary_table
.range::<DatabaseInnerKeyValue>(start_with.clone()..)
.unwrap();
SecondaryScanIteratorStartWith {
primary_table: &self.primary_table,
start_with,
range,
_marker: PhantomData::default(),
}
}
}
pub struct SecondaryScanIterator<'a, PrimaryTable, T: Input>
where
PrimaryTable: redb::ReadableTable<DatabaseInnerKeyValue, &'static [u8]>,
{
pub(crate) primary_table: &'a PrimaryTable,
pub(crate) range: redb::Range<'a, DatabaseInnerKeyValue, DatabaseInnerKeyValue>,
pub(crate) _marker: PhantomData<T>,
}
impl<'a, PrimaryTable, T: Input> Iterator for SecondaryScanIterator<'a, PrimaryTable, T>
where
PrimaryTable: redb::ReadableTable<DatabaseInnerKeyValue, &'static [u8]>,
{
type Item = T;
fn next(&mut self) -> Option<Self::Item> {
match self.range.next() {
Some(Ok((_, key))) => {
if let Ok(value) = self.primary_table.get(key.value()) {
unwrap_item(value)
} else {
None
}
}
_ => None,
}
}
}
impl<'a, PrimaryTable, T: Input> DoubleEndedIterator for SecondaryScanIterator<'a, PrimaryTable, T>
where
PrimaryTable: redb::ReadableTable<DatabaseInnerKeyValue, &'static [u8]>,
{
fn next_back(&mut self) -> Option<Self::Item> {
match self.range.next_back() {
Some(Ok((_, key))) => unwrap_item(self.primary_table.get(key.value()).unwrap()),
_ => None,
}
}
}
pub struct SecondaryScanIteratorStartWith<'a, PrimaryTable, T>
where
PrimaryTable: redb::ReadableTable<DatabaseInnerKeyValue, &'static [u8]>,
T: Input,
{
pub(crate) primary_table: &'a PrimaryTable,
pub(crate) start_with: DatabaseInnerKeyValue,
pub(crate) range: redb::Range<'a, DatabaseInnerKeyValue, DatabaseInnerKeyValue>,
pub(crate) _marker: PhantomData<T>,
}
impl<'a, PrimaryTable, T> Iterator for SecondaryScanIteratorStartWith<'a, PrimaryTable, T>
where
PrimaryTable: redb::ReadableTable<DatabaseInnerKeyValue, &'static [u8]>,
T: Input,
{
type Item = T;
fn next(&mut self) -> Option<Self::Item> {
match self.range.next() {
Some(Ok((secondary_key, primary_key))) => {
if secondary_key
.value()
.as_slice()
.starts_with(self.start_with.as_slice())
{
unwrap_item(self.primary_table.get(primary_key.value()).unwrap())
} else {
None
}
}
_ => None,
}
}
}