Struct mmtkvdb::EnvRo

pub struct EnvRo { /* private fields */ }

Read-only handle for accessing environment that stores key-value databases

An environment can be opened using EnvBuilder.

Use EnvRo::open_db to retrieve database handles and EnvRo::txn_ro to start a read-only transaction.

It’s possible to clone the handle, in which case the environment will be closed when the last handle is dropped.

It’s also possible to create a read-only handle from a read-write handle (EnvRw) by invoking .clone(), which clones the referenced EnvRo through deref coercion (see example for EnvBuilder).

Implementations

impl EnvRo

pub fn txn_ro(&self) -> Result<TxnRo<'_>>

Start read-only transaction

pub fn max_keysize(&self) -> usize

Get maximum size of keys and duplicate data

pub fn valid_keysize<'kr, K, KRef>(&self, key: KRef) -> boolwhere
K: ?Sized + Storable + 'kr,
KRef: StorableRef<'kr, K>,

Checks if key or duplicate data has valid size

pub unsafe fn open_dbs<'a, K, V, C>(
&self,
options: impl IntoIterator<IntoIter = impl Iterator<Item = &'a DbSpec<K, V, C>> + ExactSizeIterator>
) -> Result<Vec<Db<K, V, C>>>where
K: ?Sized + Storable + 'a,
V: ?Sized + Storable + 'a,
C: Constraint,

Open databases in environment

SAFETY: If a database exists already, it must have been created with compatible options.

pub unsafe fn open_db<K, V, C>(
&self,
options: &DbSpec<K, V, C>
) -> Result<Db<K, V, C>>where
K: ?Sized + Storable,
V: ?Sized + Storable,
C: Constraint,

Open database in environment

SAFETY: If a database exists already, it must have been created with compatible options.

pub fn clear_stale_readers(&self) -> Result<()>

Clear stale readers

Refer to LMDB’s documentation when to clear stale readers

Trait Implementations

impl Clone for EnvRo

fn clone(&self) -> EnvRo

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for EnvRo

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl EnvRef for &EnvRo

unsafe fn open_or_create_dbs<'a, K, V, C>(
&mut self,
options: impl IntoIterator<IntoIter = impl Iterator<Item = &'a DbSpec<K, V, C>> + ExactSizeIterator>
) -> Result<Vec<Db<K, V, C>>>where
K: Storable + ?Sized + 'a,
V: Storable + ?Sized + 'a,
C: Constraint,

Open databases in environment and, if possible, create if non-existing

unsafe fn open_or_create_db<K, V, C>(
&mut self,
options: &DbSpec<K, V, C>
) -> Result<Db<K, V, C>>where
K: Storable + ?Sized,
V: Storable + ?Sized,
C: Constraint,

Open database in environment and, if possible, create if non-existing

impl Hash for EnvRo

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)where
H: Hasher,
Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq<EnvRo> for EnvRo

fn eq(&self, other: &EnvRo) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Eq for EnvRo

impl StructuralEq for EnvRo

impl StructuralPartialEq for EnvRo