Trait sc_client_db::Database [−][src]
Required methods
pub fn get(&self, col: u32, key: &[u8]) -> Option<Vec<u8, Global>>
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Retrieve the value previously stored against key
or None
if
key
is not currently in the database.
pub fn lookup(&self, hash: &H) -> Option<Vec<u8, Global>>
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Retrieve the first preimage previously store
d for hash
or None
if no preimage is
currently stored.
Provided methods
pub fn commit(&self, transaction: Transaction<H>) -> Result<(), DatabaseError>
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Commit the transaction
to the database atomically. Any further calls to get
or lookup
will reflect the new state.
pub fn commit_ref(
&self,
transaction: &mut dyn Iterator<Item = ChangeRef<'a, H>>
) -> Result<(), DatabaseError>
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&self,
transaction: &mut dyn Iterator<Item = ChangeRef<'a, H>>
) -> Result<(), DatabaseError>
Commit the transaction
to the database atomically. Any further calls to get
or lookup
will reflect the new state.
pub fn with_get(&self, col: u32, key: &[u8], f: &mut dyn FnMut(&[u8]))
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Call f
with the value previously stored against key
.
This may be faster than get
since it doesn’t allocate.
Use with_get
helper function if you need f
to return a value from f
pub fn set(
&self,
col: u32,
key: &[u8],
value: &[u8]
) -> Result<(), DatabaseError>
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&self,
col: u32,
key: &[u8],
value: &[u8]
) -> Result<(), DatabaseError>
Set the value of key
in col
to value
, replacing anything that is there currently.
pub fn remove(&self, col: u32, key: &[u8]) -> Result<(), DatabaseError>
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Remove the value of key
in col
.
pub fn with_lookup(&self, hash: &H, f: &mut dyn FnMut(&[u8]))
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Call f
with the preimage stored for hash
and return the result, or None
if no preimage
is currently stored.
This may be faster than lookup
since it doesn’t allocate.
Use with_lookup
helper function if you need f
to return a value from f
pub fn store(&self, hash: &H, preimage: &[u8]) -> Result<(), DatabaseError>
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Store the preimage
of hash
into the database, so that it may be looked up later with
Database::lookup
. This may be called multiple times, but Database::lookup
but subsequent
calls will ignore preimage
and simply increase the number of references on hash
.
pub fn release(&self, hash: &H) -> Result<(), DatabaseError>
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Release the preimage of hash
from the database. An equal number of these to the number of
corresponding store
s must have been given before it is legal for Database::lookup
to
be unable to provide the preimage.
Trait Implementations
Implementations on Foreign Types
impl<H> Database<H> for MemDb<H> where
H: Clone + Send + Sync + Eq + PartialEq<H> + Default + Hash,
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H: Clone + Send + Sync + Eq + PartialEq<H> + Default + Hash,