pub trait Cursor {
// Required methods
fn seek_to_first(&mut self) -> Result<(), Error>;
fn seek_to_last(&mut self) -> Result<(), Error>;
fn seek(&mut self, key: &[u8]) -> Result<(), Error>;
fn prev(&mut self) -> Result<(), Error>;
fn next(&mut self) -> Result<(), Error>;
fn key(&self) -> Option<KeyRef<"_>>;
fn value(&self) -> Option<&[u8]>;
// Provided method
fn key_value(&self) -> Option<KeyValueRef<"_>> { ... }
}Expand description
A Cursor allows for iterating through data.
Required Methods§
Sourcefn seek_to_first(&mut self) -> Result<(), Error>
fn seek_to_first(&mut self) -> Result<(), Error>
Seek past the first valid key-value pair to a beginning-of-stream sentinel.
Sourcefn seek_to_last(&mut self) -> Result<(), Error>
fn seek_to_last(&mut self) -> Result<(), Error>
Seek past the last valid key-value pair to an end-of-stream sentinel.
Sourcefn seek(&mut self, key: &[u8]) -> Result<(), Error>
fn seek(&mut self, key: &[u8]) -> Result<(), Error>
Seek to this key. After a call to seek, the values of [key] and [value] should return the sought-to key or the key that’s lexicographically next after key.
Sourcefn prev(&mut self) -> Result<(), Error>
fn prev(&mut self) -> Result<(), Error>
Advance the cursor forward to the lexicographically-previous key.
Sourcefn next(&mut self) -> Result<(), Error>
fn next(&mut self) -> Result<(), Error>
Advance the cursor forward to the lexicographically-next key.
Provided Methods§
Sourcefn key_value(&self) -> Option<KeyValueRef<"_>>
fn key_value(&self) -> Option<KeyValueRef<"_>>
Return a KeyValueRef corresponding to the current position of the cursor. By default this
will stitch together the values of key() and value() to make a KeyValueRef.
Trait Implementations§
Source§impl Cursor for Box<dyn Cursor>
impl Cursor for Box<dyn Cursor>
Source§fn seek_to_first(&mut self) -> Result<(), Error>
fn seek_to_first(&mut self) -> Result<(), Error>
Seek past the first valid key-value pair to a beginning-of-stream sentinel.
Source§fn seek_to_last(&mut self) -> Result<(), Error>
fn seek_to_last(&mut self) -> Result<(), Error>
Seek past the last valid key-value pair to an end-of-stream sentinel.
Source§fn seek(&mut self, key: &[u8]) -> Result<(), Error>
fn seek(&mut self, key: &[u8]) -> Result<(), Error>
Seek to this key. After a call to seek, the values of [key] and [value] should return the
sought-to key or the key that’s lexicographically next after key.
Source§fn prev(&mut self) -> Result<(), Error>
fn prev(&mut self) -> Result<(), Error>
Advance the cursor forward to the lexicographically-previous key.
Source§fn next(&mut self) -> Result<(), Error>
fn next(&mut self) -> Result<(), Error>
Advance the cursor forward to the lexicographically-next key.
Source§fn key(&self) -> Option<KeyRef<"_>>
fn key(&self) -> Option<KeyRef<"_>>
The key where this cursor is positioned, or None if the cursor is positioned at the bounds.
Source§fn value(&self) -> Option<&[u8]>
fn value(&self) -> Option<&[u8]>
The value where this cursor is positioned, or None if the cursor is positioned at a
tombstone or the limits of the cursor.
Source§fn key_value(&self) -> Option<KeyValueRef<"_>>
fn key_value(&self) -> Option<KeyValueRef<"_>>
Return a KeyValueRef corresponding to the current position of the cursor. By default this
will stitch together the values of
key() and value() to make a KeyValueRef.