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package graph

import ""


Package Files

hasa.go linksto.go quadstore.go quadwriter.go registry.go transaction.go


var (
    ErrDatabaseExists = errors.New("quadstore: cannot init; database already exists")
    ErrNotInitialized = errors.New("quadstore: not initialized")
var (
    ErrQuadExists    = errors.New("quad exists")
    ErrQuadNotExist  = errors.New("quad does not exist")
    ErrInvalidAction = errors.New("invalid action")
    ErrNodeNotExists = errors.New("node does not exist")
var (
    // IgnoreDuplicates specifies whether duplicate quads
    // cause an error during loading or are ignored.
    IgnoreDuplicates = true

    // IgnoreMissing specifies whether missing quads
    // cause an error during deletion or are ignored.
    IgnoreMissing = false
var (
    ErrQuadStoreNotRegistred  = fmt.Errorf("this QuadStore is not registered")
    ErrQuadStoreNotPersistent = fmt.Errorf("cannot specify address for non-persistent backend")
    ErrOperationNotSupported  = fmt.Errorf("this Operation is not supported")

func InitQuadStore Uses

func InitQuadStore(name string, dbpath string, opts Options) error

func IsInvalidAction Uses

func IsInvalidAction(err error) bool

IsInvalidAction returns whether an error is a DeltaError with the Err field equal to ErrInvalidAction.

func IsPersistent Uses

func IsPersistent(name string) bool

func IsQuadExist Uses

func IsQuadExist(err error) bool

IsQuadExist returns whether an error is a DeltaError with the Err field equal to ErrQuadExists.

func IsQuadNotExist Uses

func IsQuadNotExist(err error) bool

IsQuadNotExist returns whether an error is a DeltaError with the Err field equal to ErrQuadNotExist.

func IsRegistered Uses

func IsRegistered(name string) bool

func NewQuadStoreReader Uses

func NewQuadStoreReader(qs QuadStore) quad.ReadSkipCloser

NewQuadStoreReader creates a quad reader for a given QuadStore.

func NewResultReader Uses

func NewResultReader(qs QuadStore, it iterator.Scanner) quad.ReadSkipCloser

NewResultReader creates a quad reader for a given QuadStore and iterator. If iterator is nil QuadsAllIterator will be used.

Only quads returned by iterator's Result will be used.

Iterator will be closed with the reader.

func NewTxWriter Uses

func NewTxWriter(tx *Transaction, p Procedure) quad.Writer

NewTxWriter creates a writer that applies a given procedures for all quads in stream. If procedure is zero, Add operation will be used.

func QuadStores Uses

func QuadStores() []string

func RegisterQuadStore Uses

func RegisterQuadStore(name string, register QuadStoreRegistration)

func RegisterWriter Uses

func RegisterWriter(name string, newFunc NewQuadWriterFunc)

func UpgradeQuadStore Uses

func UpgradeQuadStore(name string, dbpath string, opts Options) error

func ValuesOf Uses

func ValuesOf(ctx context.Context, qs refs.Namer, vals []Ref) ([]quad.Value, error)

func WriterMethods Uses

func WriterMethods() []string

type BatchWriter Uses

type BatchWriter interface {
    Flush() error

func NewRemover Uses

func NewRemover(qs QuadWriter) BatchWriter

NewRemover creates a quad writer for a given QuadStore which removes quads instead of adding them.

func NewWriter Uses

func NewWriter(qs QuadWriter) BatchWriter

NewWriter creates a quad writer for a given QuadStore.

Caller must call Flush or Close to flush an internal buffer.

type Delta Uses

type Delta struct {
    Quad   quad.Quad
    Action Procedure

type DeltaError Uses

type DeltaError struct {
    Delta Delta
    Err   error

DeltaError records an error and the delta that caused it.

func (*DeltaError) Error Uses

func (e *DeltaError) Error() string

type Handle Uses

type Handle struct {

func (*Handle) Close Uses

func (h *Handle) Close() error

type HasA Uses

type HasA struct {
    // contains filtered or unexported fields

A HasA consists of a reference back to the graph.QuadStore that it references, a primary subiterator, a direction in which the quads for that subiterator point, and a temporary holder for the iterator generated on Contains().

func NewHasA Uses

func NewHasA(qs QuadIndexer, subIt iterator.Shape, d quad.Direction) *HasA

NewHasA construct a new HasA iterator, given the quad subiterator, and the quad direction for which it stands.

func (*HasA) Direction Uses

func (it *HasA) Direction() quad.Direction

Direction accessor.

func (*HasA) Iterate Uses

func (it *HasA) Iterate() iterator.Scanner

func (*HasA) Lookup Uses

func (it *HasA) Lookup() iterator.Index

func (*HasA) Optimize Uses

func (it *HasA) Optimize(ctx context.Context) (iterator.Shape, bool)

Optimize pass the Optimize() call along to the subiterator. If it becomes Null, then the HasA becomes Null (there are no quads that have any directions).

func (*HasA) Stats Uses

func (it *HasA) Stats(ctx context.Context) (iterator.Costs, error)

Stats returns the statistics on the HasA iterator. This is curious. Next cost is easy, it's an extra call or so on top of the subiterator Next cost. ContainsCost involves going to the graph.QuadStore, iterating out values, and hoping one sticks -- potentially expensive, depending on fanout. Size, however, is potentially smaller. we know at worst it's the size of the subiterator, but if there are many repeated values, it could be much smaller in totality.

func (*HasA) String Uses

func (it *HasA) String() string

func (*HasA) SubIterators Uses

func (it *HasA) SubIterators() []iterator.Shape

SubIterators returns our sole subiterator.

type IgnoreOpts Uses

type IgnoreOpts struct {
    IgnoreDup, IgnoreMissing bool

type InitStoreFunc Uses

type InitStoreFunc func(string, Options) error

type LinksTo Uses

type LinksTo struct {
    // contains filtered or unexported fields

A LinksTo has a reference back to the graph.QuadStore (to create the iterators for each node) the subiterator, and the direction the iterator comes from. `next_it` is the tempoarary iterator held per result in `primary_it`.

func NewLinksTo Uses

func NewLinksTo(qs QuadIndexer, it iterator.Shape, d quad.Direction) *LinksTo

NewLinksTo construct a new LinksTo iterator around a direction and a subiterator of nodes.

func (*LinksTo) Direction Uses

func (it *LinksTo) Direction() quad.Direction

Direction returns the direction under consideration.

func (*LinksTo) Iterate Uses

func (it *LinksTo) Iterate() iterator.Scanner

func (*LinksTo) Lookup Uses

func (it *LinksTo) Lookup() iterator.Index

func (*LinksTo) Optimize Uses

func (it *LinksTo) Optimize(ctx context.Context) (iterator.Shape, bool)

Optimize the LinksTo, by replacing it if it can be.

func (*LinksTo) Stats Uses

func (it *LinksTo) Stats(ctx context.Context) (iterator.Costs, error)

Stats returns a guess as to how big or costly it is to next the iterator.

func (*LinksTo) String Uses

func (it *LinksTo) String() string

func (*LinksTo) SubIterators Uses

func (it *LinksTo) SubIterators() []iterator.Shape

SubIterators returns a list containing only our subiterator.

type NewQuadWriterFunc Uses

type NewQuadWriterFunc func(QuadStore, Options) (QuadWriter, error)

type NewStoreFunc Uses

type NewStoreFunc func(string, Options) (QuadStore, error)

type Options Uses

type Options map[string]interface{}

func (Options) BoolKey Uses

func (d Options) BoolKey(key string, def bool) (bool, error)

func (Options) IntKey Uses

func (d Options) IntKey(key string, def int) (int, error)

func (Options) StringKey Uses

func (d Options) StringKey(key string, def string) (string, error)

type Procedure Uses

type Procedure int8
const (
    Add    Procedure = +1
    Delete Procedure = -1

The different types of actions a transaction can do.

func (Procedure) String Uses

func (p Procedure) String() string

type QuadIndexer Uses

type QuadIndexer interface {
    // Given an opaque token, returns the quad for that token from the store.
    Quad(Ref) quad.Quad

    // Given a direction and a token, creates an iterator of links which have
    // that node token in that directional field.
    QuadIterator(quad.Direction, Ref) iterator.Shape

    // QuadIteratorSize returns an estimated size of an iterator.
    QuadIteratorSize(ctx context.Context, d quad.Direction, v Ref) (refs.Size, error)

    // Convenience function for speed. Given a quad token and a direction
    // return the node token for that direction. Sometimes, a QuadStore
    // can do this without going all the way to the backing store, and
    // gives the QuadStore the opportunity to make this optimization.
    // Iterators will call this. At worst, a valid implementation is
    //  qs.ValueOf(qs.Quad(id).Get(dir))
    QuadDirection(id Ref, d quad.Direction) Ref

    // Stats returns the number of nodes and quads currently stored.
    // Exact flag controls the correctness of the value. It can be an estimation, or a precise calculation.
    // The quadstore may have a fast way of retrieving the precise stats, in this case it may ignore 'exact'
    // flag and always return correct stats (with an appropriate flags set in the output).
    Stats(ctx context.Context, exact bool) (Stats, error)

type QuadStore Uses

type QuadStore interface {

    // The only way in is through building a transaction, which
    // is done by a replication strategy.
    ApplyDeltas(in []Delta, opts IgnoreOpts) error

    // NewQuadWriter starts a batch quad import process.
    // The order of changes is not guaranteed, neither is the order and result of concurrent ApplyDeltas.
    NewQuadWriter() (quad.WriteCloser, error)

    // Returns an iterator enumerating all nodes in the graph.
    NodesAllIterator() iterator.Shape

    // Returns an iterator enumerating all links in the graph.
    QuadsAllIterator() iterator.Shape

    // Close the quad store and clean up. (Flush to disk, cleanly
    // sever connections, etc)
    Close() error

func NewQuadStore Uses

func NewQuadStore(name string, dbpath string, opts Options) (QuadStore, error)

func Unwrap Uses

func Unwrap(qs QuadStore) QuadStore

Unwrap returns an original QuadStore value if it was wrapped by Handle. This prevents shadowing of optional interface implementations.

type QuadStoreRegistration Uses

type QuadStoreRegistration struct {
    NewFunc      NewStoreFunc
    UpgradeFunc  UpgradeStoreFunc
    InitFunc     InitStoreFunc
    IsPersistent bool

type QuadWriter Uses

type QuadWriter interface {
    // AddQuad adds a quad to the store.
    AddQuad(quad.Quad) error

    // TODO(barakmich): Deprecate in favor of transaction.
    // AddQuadSet adds a set of quads to the store, atomically if possible.
    AddQuadSet([]quad.Quad) error

    // RemoveQuad removes a quad matching the given one  from the database,
    // if it exists. Does nothing otherwise.
    RemoveQuad(quad.Quad) error

    // ApplyTransaction applies a set of quad changes.
    ApplyTransaction(*Transaction) error

    // RemoveNode removes all quads which have the given node as subject, predicate, object, or label.
    // It returns ErrNodeNotExists if node is missing.
    RemoveNode(quad.Value) error

    // Close cleans up replication and closes the writing aspect of the database.
    Close() error

func NewQuadWriter Uses

func NewQuadWriter(name string, qs QuadStore, opts Options) (QuadWriter, error)

type Ref Uses

type Ref = refs.Ref

Ref defines an opaque "quad store reference" type. However the backend wishes to implement it, a Ref is merely a token to a quad or a node that the backing store itself understands, and the base iterators pass around.

For example, in a very traditional, graphd-style graph, these are int64s (guids of the primitives). In a very direct sort of graph, these could be pointers to structs, or merely quads, or whatever works best for the backing store.

These must be comparable, or return a comparable version on Key.

func RefsOf Uses

func RefsOf(ctx context.Context, qs refs.Namer, nodes []quad.Value) ([]Ref, error)

type Stats Uses

type Stats struct {
    Nodes refs.Size // number of nodes
    Quads refs.Size // number of quads

Stats of a graph.

type Transaction Uses

type Transaction struct {
    // Deltas stores the deltas in the right order
    Deltas []Delta
    // contains filtered or unexported fields

Transaction stores a bunch of Deltas to apply together in an atomic step on the database.

func NewTransaction Uses

func NewTransaction() *Transaction

NewTransaction initialize a new transaction.

func NewTransactionN Uses

func NewTransactionN(n int) *Transaction

NewTransactionN initialize a new transaction with a predefined capacity.

func (*Transaction) AddQuad Uses

func (t *Transaction) AddQuad(q quad.Quad)

AddQuad adds a new quad to the transaction if it is not already present in it. If there is a 'remove' delta for that quad, it will remove that delta from the transaction instead of actually adding the quad.

func (*Transaction) RemoveQuad Uses

func (t *Transaction) RemoveQuad(q quad.Quad)

RemoveQuad adds a quad to remove to the transaction. The quad will be removed from the database if it is not present in the transaction, otherwise it simply remove it from the transaction.

type UpgradeStoreFunc Uses

type UpgradeStoreFunc func(string, Options) error


memstorePackage b implements a B+tree.
protoPackage proto is a generated protocol buffer package.

Package graph imports 10 packages (graph) and is imported by 782 packages. Updated 2020-03-18. Refresh now. Tools for package owners.