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// Copyright (c) 2024-present, fjall-rs
// This source code is licensed under both the Apache 2.0 and MIT License
// (found in the LICENSE-* files in the repository)
use lsm_tree::{Guard as _Guard, UserKey, UserValue};
/// Guard to access key-value pairs
pub struct Guard(pub(crate) lsm_tree::IterGuardImpl);
impl Guard {
// TODO: is_ok?
/// Accesses the key-value pair if the predicate returns `true`.
///
/// The predicate receives the key - if returning `false`, the value
/// may not be loaded if the tree is key-value separated.
///
/// # Examples
///
/// ```
/// # use fjall::{Database, KeyspaceCreateOptions};
/// #
/// # let folder = tempfile::tempdir()?;
/// # let db = Database::builder(folder).open()?;
/// # let tree = db.keyspace("default", KeyspaceCreateOptions::default)?;
/// tree.insert("abc", "my_value")?;
///
/// let (k,v) = tree.prefix("a")
/// .next()
/// .unwrap()
/// .into_inner_if(|key| key.starts_with(b"a"))?;
///
/// assert_eq!(b"abc", &*k);
/// assert_eq!(Some(b"my_value".as_slice()), v.as_deref());
/// #
/// # Ok::<(), fjall::Error>(())
/// ```
///
/// # Errors
///
/// Will return `Err` if an IO error occurs.
pub fn into_inner_if(
self,
pred: impl Fn(&crate::UserKey) -> bool,
) -> crate::Result<(UserKey, Option<UserValue>)> {
self.0.into_inner_if(pred).map_err(Into::into)
}
/// Returns the key-value tuple.
///
/// # Examples
///
/// ```
/// # use fjall::{Database, KeyspaceCreateOptions};
/// #
/// # let folder = tempfile::tempdir()?;
/// # let db = Database::builder(folder).open()?;
/// # let tree = db.keyspace("default", KeyspaceCreateOptions::default)?;
/// tree.insert("a", "my_value")?;
///
/// let (k,v) = tree.prefix("a")
/// .next()
/// .unwrap()
/// .into_inner()?;
///
/// assert_eq!(b"a", &*k);
/// assert_eq!(b"my_value", &*v);
/// #
/// # Ok::<(), fjall::Error>(())
/// ```
///
/// # Errors
///
/// Will return `Err` if an IO error occurs.
pub fn into_inner(self) -> crate::Result<crate::KvPair> {
self.0.into_inner().map_err(Into::into)
}
/// Returns the key.
///
/// # Examples
///
/// ```
/// # use fjall::{Database, KeyspaceCreateOptions};
/// #
/// # let folder = tempfile::tempdir()?;
/// # let db = Database::builder(folder).open()?;
/// # let tree = db.keyspace("default", KeyspaceCreateOptions::default)?;
/// tree.insert("a", "my_value")?;
///
/// let item = tree.prefix("a").next().unwrap().key()?;
/// assert_eq!(b"a", &*item);
/// #
/// # Ok::<(), fjall::Error>(())
/// ```
///
/// # Errors
///
/// Will return `Err` if an IO error occurs.
pub fn key(self) -> crate::Result<crate::UserKey> {
self.0.key().map_err(Into::into)
}
/// Returns the value size.
///
/// # Examples
///
/// ```
/// # use fjall::{Database, KeyspaceCreateOptions};
/// #
/// # let folder = tempfile::tempdir()?;
/// # let db = Database::builder(folder).open()?;
/// # let tree = db.keyspace("default", KeyspaceCreateOptions::default)?;
/// tree.insert("a", "my_value")?;
///
/// let item = tree.prefix("a").next().unwrap().size()?;
/// assert_eq!(8, item);
/// #
/// # Ok::<(), fjall::Error>(())
/// ```
///
/// # Errors
///
/// Will return `Err` if an IO error occurs.
pub fn size(self) -> crate::Result<u32> {
self.0.size().map_err(Into::into)
}
/// Returns the value.
///
/// # Examples
///
/// ```
/// # use fjall::{Database, KeyspaceCreateOptions};
/// #
/// # let folder = tempfile::tempdir()?;
/// # let db = Database::builder(folder).open()?;
/// # let tree = db.keyspace("default", KeyspaceCreateOptions::default)?;
/// tree.insert("a", "my_value")?;
///
/// let item = tree.prefix("a").next().unwrap().value()?;
/// assert_eq!(b"my_value", &*item);
/// #
/// # Ok::<(), fjall::Error>(())
/// ```
///
/// # Errors
///
/// Will return `Err` if an IO error occurs.
pub fn value(self) -> crate::Result<crate::UserValue> {
self.0.value().map_err(Into::into)
}
}