Documentation
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Overview ¶
Package trie implements Merkle Patricia Tries.
Index ¶
- Constants
- type Batch
- type Database
- func (db *Database) Cap(limit common.StorageSize) error
- func (db *Database) Commit(node common.Hash, report bool) error
- func (db *Database) Dereference(root common.Hash)
- func (db *Database) DiskDB() DatabaseReader
- func (db *Database) InsertBlob(hash common.Hash, blob []byte)
- func (db *Database) Node(hash common.Hash) ([]byte, error)
- func (db *Database) Nodes() []common.Hash
- func (db *Database) Reference(child common.Hash, parent common.Hash)
- func (db *Database) Size() (common.StorageSize, common.StorageSize)
- type DatabaseReader
- type Deleter
- type DiskDatabase
- type Iterator
- type LeafCallback
- type MissingNodeError
- type NodeIterator
- type Putter
- type Trie
- func (t *Trie) Commit(onleaf LeafCallback) (root common.Hash, err error)
- func (t *Trie) Delete(key []byte)
- func (t *Trie) Get(key []byte) []byte
- func (t *Trie) Hash() common.Hash
- func (t *Trie) NodeIterator(start []byte) NodeIterator
- func (t *Trie) Root() []byte
- func (t *Trie) SetCacheLimit(l uint16)
- func (t *Trie) TryDelete(key []byte) error
- func (t *Trie) TryGet(key []byte) ([]byte, error)
- func (t *Trie) TryUpdate(key, value []byte) error
- func (t *Trie) Update(key, value []byte)
Constants ¶
const IdealBatchSize = 100 * 1024
Code using batches should try to add this much data to the batch. The value was determined empirically.
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type Batch ¶
type Batch interface {
Putter
Deleter
ValueSize() int // amount of data in the batch
Write() error
// Reset resets the batch for reuse
Reset()
}
Batch is a write-only database that commits changes to its host database when Write is called. Batch cannot be used concurrently.
type Database ¶
type Database struct {
// contains filtered or unexported fields
}
Database is an intermediate write layer between the trie data structures and the disk database. The aim is to accumulate trie writes in-memory and only periodically flush a couple tries to disk, garbage collecting the remainder.
func NewDatabase ¶
func NewDatabase(diskdb DiskDatabase) *Database
NewDatabase creates a new trie database to store ephemeral trie content before its written out to disk or garbage collected. No read cache is created, so all data retrievals will hit the underlying disk database.
func NewDatabaseWithCache ¶
func NewDatabaseWithCache(diskdb DiskDatabase, cache int) *Database
NewDatabaseWithCache creates a new trie database to store ephemeral trie content before its written out to disk or garbage collected. It also acts as a read cache for nodes loaded from disk.
func (*Database) Cap ¶
func (db *Database) Cap(limit common.StorageSize) error
Cap iteratively flushes old but still referenced trie nodes until the total memory usage goes below the given threshold.
func (*Database) Commit ¶
Commit iterates over all the children of a particular node, writes them out to disk, forcefully tearing down all references in both directions.
As a side effect, all pre-images accumulated up to this point are also written.
func (*Database) Dereference ¶
Dereference removes an existing reference from a root node.
func (*Database) DiskDB ¶
func (db *Database) DiskDB() DatabaseReader
DiskDB retrieves the persistent storage backing the trie database.
func (*Database) InsertBlob ¶
InsertBlob writes a new reference tracked blob to the memory database if it's yet unknown. This method should only be used for non-trie nodes that require reference counting, since trie nodes are garbage collected directly through their embedded children.
func (*Database) Node ¶
Node retrieves an encoded cached trie node from memory. If it cannot be found cached, the method queries the persistent database for the content.
func (*Database) Nodes ¶
Nodes retrieves the hashes of all the nodes cached within the memory database. This method is extremely expensive and should only be used to validate internal states in test code.
func (*Database) Size ¶
func (db *Database) Size() (common.StorageSize, common.StorageSize)
Size returns the current storage size of the memory cache in front of the persistent database layer.
type DatabaseReader ¶
type DatabaseReader interface {
// Get retrieves the value associated with key from the database.
Get(key []byte) (value []byte, err error)
// Has retrieves whether a key is present in the database.
Has(key []byte) (bool, error)
}
DatabaseReader wraps the Get and Has method of a backing store for the trie.
type Deleter ¶
Deleter wraps the database delete operation supported by both batches and regular databases.
type DiskDatabase ¶
type DiskDatabase interface {
Putter
Deleter
Get(key []byte) ([]byte, error)
Has(key []byte) (bool, error)
Close()
NewBatch() Batch
}
Database wraps all database operations. All methods are safe for concurrent use.
type Iterator ¶
type Iterator struct {
Key []byte // Current data key on which the iterator is positioned on
Value []byte // Current data value on which the iterator is positioned on
Err error
// contains filtered or unexported fields
}
Iterator is a key-value trie iterator that traverses a Trie.
func NewIterator ¶
func NewIterator(it NodeIterator) *Iterator
NewIterator creates a new key-value iterator from a node iterator
type LeafCallback ¶
LeafCallback is a callback type invoked when a trie operation reaches a leaf node. It's used by state sync and commit to allow handling external references between account and storage tries.
type MissingNodeError ¶
type MissingNodeError struct {
NodeHash common.Hash // hash of the missing node
Path []byte // hex-encoded path to the missing node
}
MissingNodeError is returned by the trie functions (TryGet, TryUpdate, TryDelete) in the case where a trie node is not present in the local database. It contains information necessary for retrieving the missing node.
func (*MissingNodeError) Error ¶
func (err *MissingNodeError) Error() string
type NodeIterator ¶
type NodeIterator interface {
// Next moves the iterator to the next node. If the parameter is false, any child
// nodes will be skipped.
Next(bool) bool
// Error returns the error status of the iterator.
Error() error
// Hash returns the hash of the current node.
Hash() common.Hash
// Parent returns the hash of the parent of the current node. The hash may be the one
// grandparent if the immediate parent is an internal node with no hash.
Parent() common.Hash
// Path returns the hex-encoded path to the current node.
// Callers must not retain references to the return value after calling Next.
// For leaf nodes, the last element of the path is the 'terminator symbol' 0x10.
Path() []byte
// Leaf returns true iff the current node is a leaf node.
Leaf() bool
// LeafKey returns the key of the leaf. The method panics if the iterator is not
// positioned at a leaf. Callers must not retain references to the value after
// calling Next.
LeafKey() []byte
// LeafBlob returns the content of the leaf. The method panics if the iterator
// is not positioned at a leaf. Callers must not retain references to the value
// after calling Next.
LeafBlob() []byte
// LeafProof returns the Merkle proof of the leaf. The method panics if the
// iterator is not positioned at a leaf. Callers must not retain references
// to the value after calling Next.
LeafProof() [][]byte
}
NodeIterator is an iterator to traverse the trie pre-order.
func NewDifferenceIterator ¶
func NewDifferenceIterator(a, b NodeIterator) (NodeIterator, *int)
NewDifferenceIterator constructs a NodeIterator that iterates over elements in b that are not in a. Returns the iterator, and a pointer to an integer recording the number of nodes seen.
func NewUnionIterator ¶
func NewUnionIterator(iters []NodeIterator) (NodeIterator, *int)
NewUnionIterator constructs a NodeIterator that iterates over elements in the union of the provided NodeIterators. Returns the iterator, and a pointer to an integer recording the number of nodes visited.
type Putter ¶
Putter wraps the database write operation supported by both batches and regular databases.
type Trie ¶
type Trie struct {
// contains filtered or unexported fields
}
Trie is a Merkle Patricia Trie. The zero value is an empty trie with no database. Use New to create a trie that sits on top of a database.
Trie is not safe for concurrent use.
func (*Trie) Commit ¶
func (t *Trie) Commit(onleaf LeafCallback) (root common.Hash, err error)
Commit writes all nodes to the trie's memory database, tracking the internal and external (for account tries) references.
func (*Trie) Get ¶
Get returns the value for key stored in the trie. The value bytes must not be modified by the caller.
func (*Trie) Hash ¶
Hash returns the root hash of the trie. It does not write to the database and can be used even if the trie doesn't have one.
func (*Trie) NodeIterator ¶
func (t *Trie) NodeIterator(start []byte) NodeIterator
NodeIterator returns an iterator that returns nodes of the trie. Iteration starts at the key after the given start key.
func (*Trie) SetCacheLimit ¶
SetCacheLimit sets the number of 'cache generations' to keep. A cache generation is created by a call to Commit.
func (*Trie) TryDelete ¶
TryDelete removes any existing value for key from the trie. If a node was not found in the database, a MissingNodeError is returned.
func (*Trie) TryGet ¶
TryGet returns the value for key stored in the trie. The value bytes must not be modified by the caller. If a node was not found in the database, a MissingNodeError is returned.
func (*Trie) TryUpdate ¶
TryUpdate associates key with value in the trie. Subsequent calls to Get will return value. If value has length zero, any existing value is deleted from the trie and calls to Get will return nil.
The value bytes must not be modified by the caller while they are stored in the trie.
If a node was not found in the database, a MissingNodeError is returned.
func (*Trie) Update ¶
Update associates key with value in the trie. Subsequent calls to Get will return value. If value has length zero, any existing value is deleted from the trie and calls to Get will return nil.
The value bytes must not be modified by the caller while they are stored in the trie.
Source Files