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use super::advance_key;
use crate::*;
fn move_on_last_prefix<'txn>(
cursor: &mut RoCursor<'txn>,
prefix: Vec<u8>,
) -> Result<Option<(&'txn [u8], &'txn [u8])>> {
match advance_key(prefix) {
Some(next_prefix) => cursor
.move_on_key_greater_than_or_equal_to(&next_prefix)
.and_then(|_| cursor.move_on_prev()),
None => cursor.move_on_last(),
}
}
pub struct RoPrefix<'txn> {
cursor: RoCursor<'txn>,
prefix: Vec<u8>,
move_on_first: bool,
}
impl<'txn> RoPrefix<'txn> {
pub(crate) fn new(cursor: RoCursor<'txn>, prefix: Vec<u8>) -> RoPrefix<'txn> {
RoPrefix {
cursor,
prefix,
move_on_first: true,
}
}
}
impl<'txn> Iterator for RoPrefix<'txn> {
type Item = Result<(&'txn [u8], &'txn [u8])>;
fn next(&mut self) -> Option<Self::Item> {
let result = if self.move_on_first {
self.move_on_first = false;
self.cursor
.move_on_key_greater_than_or_equal_to(&self.prefix)
} else {
self.cursor.move_on_next()
};
result
.map(|option| option.filter(|(k, _)| k.starts_with(&self.prefix)))
.transpose()
}
fn last(mut self) -> Option<Self::Item> {
let result = if self.move_on_first {
move_on_last_prefix(&mut self.cursor, self.prefix.clone())
} else {
match (
self.cursor.current(),
move_on_last_prefix(&mut self.cursor, self.prefix.clone()),
) {
(Ok(Some((ckey, _))), Ok(Some((key, data)))) if ckey != key => {
Ok(Some((key, data)))
}
(Ok(_), Ok(_)) => Ok(None),
(Err(e), _) | (_, Err(e)) => Err(e),
}
};
result
.map(|option| option.filter(|(k, _)| k.starts_with(&self.prefix)))
.transpose()
}
}
pub struct RwPrefix<'txn> {
cursor: RwCursor<'txn>,
prefix: Vec<u8>,
move_on_first: bool,
}
impl<'txn> RwPrefix<'txn> {
pub(crate) fn new(cursor: RwCursor<'txn>, prefix: Vec<u8>) -> RwPrefix<'txn> {
RwPrefix {
cursor,
prefix,
move_on_first: true,
}
}
/// Delete the entry the cursor is currently pointing to.
///
/// Returns `true` if the entry was successfully deleted.
///
/// # Safety
///
/// It is _[undefined behavior]_ to keep a reference of a value from this database
/// while modifying it.
///
/// > [Values returned from the database are valid only until a subsequent update operation,
/// or the end of the transaction.](http://www.lmdb.tech/doc/group__mdb.html#structMDB__val).
///
/// [undefined behavior]: https://doc.rust-lang.org/reference/behavior-considered-undefined.html
pub unsafe fn del_current(&mut self) -> Result<bool> {
self.cursor.del_current()
}
/// Write a new value to the current entry.
///
/// The given key **must** be equal to the one this cursor is pointing otherwise the database
/// can be put into an inconsistent state.
///
/// Returns `true` if the entry was successfully written.
///
/// > This is intended to be used when the new data is the same size as the old.
/// > Otherwise it will simply perform a delete of the old record followed by an insert.
///
/// # Safety
///
/// It is _[undefined behavior]_ to keep a reference of a value from this database while
/// modifying it, so you can't use the key/value that comes from the cursor to feed
/// this function.
///
/// In other words: Tranform the key and value that you borrow from this database into an owned
/// version of them i.e. `&str` into `String`.
///
/// > [Values returned from the database are valid only until a subsequent update operation,
/// or the end of the transaction.](http://www.lmdb.tech/doc/group__mdb.html#structMDB__val).
///
/// [undefined behavior]: https://doc.rust-lang.org/reference/behavior-considered-undefined.html
pub unsafe fn put_current<A, B>(&mut self, key: A, data: B) -> Result<bool>
where
A: AsRef<[u8]>,
B: AsRef<[u8]>,
{
self.cursor.put_current(key.as_ref(), data.as_ref())
}
/// Append the given key/value pair to the end of the database.
///
/// If a key is inserted that is less than any previous key a `KeyExist` error
/// is returned and the key is not inserted into the database.
///
/// # Safety
///
/// It is _[undefined behavior]_ to keep a reference of a value from this database while
/// modifying it, so you can't use the key/value that comes from the cursor to feed
/// this function.
///
/// In other words: Tranform the key and value that you borrow from this database into an owned
/// version of them i.e. `&str` into `String`.
///
/// > [Values returned from the database are valid only until a subsequent update operation,
/// or the end of the transaction.](http://www.lmdb.tech/doc/group__mdb.html#structMDB__val).
///
/// [undefined behavior]: https://doc.rust-lang.org/reference/behavior-considered-undefined.html
pub unsafe fn append<A, B>(&mut self, key: A, data: B) -> Result<()>
where
A: AsRef<[u8]>,
B: AsRef<[u8]>,
{
self.cursor.append(key.as_ref(), data.as_ref())
}
}
impl<'txn> Iterator for RwPrefix<'txn> {
type Item = Result<(&'txn [u8], &'txn [u8])>;
fn next(&mut self) -> Option<Self::Item> {
let result = if self.move_on_first {
self.move_on_first = false;
self.cursor
.move_on_key_greater_than_or_equal_to(&self.prefix)
} else {
self.cursor.move_on_next()
};
result
.map(|option| option.filter(|(k, _)| k.starts_with(&self.prefix)))
.transpose()
}
fn last(mut self) -> Option<Self::Item> {
let result = if self.move_on_first {
move_on_last_prefix(&mut self.cursor, self.prefix.clone())
} else {
match (
self.cursor.current(),
move_on_last_prefix(&mut self.cursor, self.prefix.clone()),
) {
(Ok(Some((ckey, _))), Ok(Some((key, data)))) if ckey != key => {
Ok(Some((key, data)))
}
(Ok(_), Ok(_)) => Ok(None),
(Err(e), _) | (_, Err(e)) => Err(e),
}
};
result
.map(|option| option.filter(|(k, _)| k.starts_with(&self.prefix)))
.transpose()
}
}
pub struct RoRevPrefix<'txn> {
cursor: RoCursor<'txn>,
prefix: Vec<u8>,
move_on_last: bool,
}
impl<'txn> RoRevPrefix<'txn> {
pub(crate) fn new(cursor: RoCursor<'txn>, prefix: Vec<u8>) -> RoRevPrefix<'txn> {
RoRevPrefix {
cursor,
prefix,
move_on_last: true,
}
}
}
impl<'txn> Iterator for RoRevPrefix<'txn> {
type Item = Result<(&'txn [u8], &'txn [u8])>;
fn next(&mut self) -> Option<Self::Item> {
let result = if self.move_on_last {
self.move_on_last = false;
move_on_last_prefix(&mut self.cursor, self.prefix.clone())
} else {
self.cursor.move_on_prev()
};
result
.map(|option| option.filter(|(k, _)| k.starts_with(&self.prefix)))
.transpose()
}
fn last(mut self) -> Option<Self::Item> {
let result = if self.move_on_last {
self.cursor
.move_on_key_greater_than_or_equal_to(&self.prefix)
} else {
let current = self.cursor.current();
let start = self
.cursor
.move_on_key_greater_than_or_equal_to(&self.prefix);
match (current, start) {
(Ok(Some((ckey, _))), Ok(Some((key, data)))) if ckey != key => {
Ok(Some((key, data)))
}
(Ok(_), Ok(_)) => Ok(None),
(Err(e), _) | (_, Err(e)) => Err(e),
}
};
result
.map(|option| option.filter(|(k, _)| k.starts_with(&self.prefix)))
.transpose()
}
}
pub struct RwRevPrefix<'txn> {
cursor: RwCursor<'txn>,
prefix: Vec<u8>,
move_on_last: bool,
}
impl<'txn> RwRevPrefix<'txn> {
pub(crate) fn new(cursor: RwCursor<'txn>, prefix: Vec<u8>) -> RwRevPrefix<'txn> {
RwRevPrefix {
cursor,
prefix,
move_on_last: true,
}
}
/// Delete the entry the cursor is currently pointing to.
///
/// Returns `true` if the entry was successfully deleted.
///
/// # Safety
///
/// It is _[undefined behavior]_ to keep a reference of a value from this database
/// while modifying it.
///
/// > [Values returned from the database are valid only until a subsequent update operation,
/// or the end of the transaction.](http://www.lmdb.tech/doc/group__mdb.html#structMDB__val).
///
/// [undefined behavior]: https://doc.rust-lang.org/reference/behavior-considered-undefined.html
pub unsafe fn del_current(&mut self) -> Result<bool> {
self.cursor.del_current()
}
/// Write a new value to the current entry.
///
/// The given key **must** be equal to the one this cursor is pointing otherwise the database
/// can be put into an inconsistent state.
///
/// Returns `true` if the entry was successfully written.
///
/// > This is intended to be used when the new data is the same size as the old.
/// > Otherwise it will simply perform a delete of the old record followed by an insert.
///
/// # Safety
///
/// It is _[undefined behavior]_ to keep a reference of a value from this database while
/// modifying it, so you can't use the key/value that comes from the cursor to feed
/// this function.
///
/// In other words: Tranform the key and value that you borrow from this database into an owned
/// version of them i.e. `&str` into `String`.
///
/// > [Values returned from the database are valid only until a subsequent update operation,
/// or the end of the transaction.](http://www.lmdb.tech/doc/group__mdb.html#structMDB__val).
///
/// [undefined behavior]: https://doc.rust-lang.org/reference/behavior-considered-undefined.html
pub unsafe fn put_current<A, B>(&mut self, key: A, data: B) -> Result<bool>
where
A: AsRef<[u8]>,
B: AsRef<[u8]>,
{
self.cursor.put_current(key.as_ref(), data.as_ref())
}
/// Append the given key/value pair to the end of the database.
///
/// If a key is inserted that is less than any previous key a `KeyExist` error
/// is returned and the key is not inserted into the database.
///
/// # Safety
///
/// It is _[undefined behavior]_ to keep a reference of a value from this database while
/// modifying it, so you can't use the key/value that comes from the cursor to feed
/// this function.
///
/// In other words: Tranform the key and value that you borrow from this database into an owned
/// version of them i.e. `&str` into `String`.
///
/// > [Values returned from the database are valid only until a subsequent update operation,
/// or the end of the transaction.](http://www.lmdb.tech/doc/group__mdb.html#structMDB__val).
///
/// [undefined behavior]: https://doc.rust-lang.org/reference/behavior-considered-undefined.html
pub unsafe fn append<A, B>(&mut self, key: A, data: B) -> Result<()>
where
A: AsRef<[u8]>,
B: AsRef<[u8]>,
{
self.cursor.append(key.as_ref(), data.as_ref())
}
}
impl<'txn> Iterator for RwRevPrefix<'txn> {
type Item = Result<(&'txn [u8], &'txn [u8])>;
fn next(&mut self) -> Option<Self::Item> {
let result = if self.move_on_last {
self.move_on_last = false;
move_on_last_prefix(&mut self.cursor, self.prefix.clone())
} else {
self.cursor.move_on_prev()
};
result
.map(|option| option.filter(|(k, _)| k.starts_with(&self.prefix)))
.transpose()
}
fn last(mut self) -> Option<Self::Item> {
let result = if self.move_on_last {
self.cursor
.move_on_key_greater_than_or_equal_to(&self.prefix)
} else {
let current = self.cursor.current();
let start = self
.cursor
.move_on_key_greater_than_or_equal_to(&self.prefix);
match (current, start) {
(Ok(Some((ckey, _))), Ok(Some((key, data)))) if ckey != key => {
Ok(Some((key, data)))
}
(Ok(_), Ok(_)) => Ok(None),
(Err(e), _) | (_, Err(e)) => Err(e),
}
};
result
.map(|option| option.filter(|(k, _)| k.starts_with(&self.prefix)))
.transpose()
}
}