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Published: Jun 19, 2017 License: Apache-2.0 Imports: 13 Imported by: 0

Documentation

Index

Constants

This section is empty.

Variables

View Source
var (
	ErrQuadExists    = errors.New("quad exists")
	ErrQuadNotExist  = errors.New("quad does not exist")
	ErrInvalidAction = errors.New("invalid action")
)
View Source
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
)
View Source
var (
	ErrQuadStoreNotRegistred = fmt.Errorf("This QuadStore is not registered.")
	ErrOperationNotSupported = fmt.Errorf("This Operation is not supported.")
)
View Source
var ErrCannotBulkLoad = errors.New("quadstore: cannot bulk load")
View Source
var ErrDatabaseExists = errors.New("quadstore: cannot init; database already exists")

Functions

func CanNext

func CanNext(it Iterator) bool

CanNext is a helper for checking if iterator can be Next()'ed.

func ContainsLogIn

func ContainsLogIn(it Iterator, val Value)

func ContainsLogOut

func ContainsLogOut(it Iterator, val Value, good bool) bool

func Height

func Height(it Iterator, until Type) int

Height is a convienence function to measure the height of an iterator tree.

func InitQuadStore

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

func IsInvalidAction

func IsInvalidAction(err error) bool

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

func IsPersistent

func IsPersistent(name string) bool

func IsQuadExist

func IsQuadExist(err error) bool

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

func IsQuadNotExist

func IsQuadNotExist(err error) bool

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

func IsRegistered

func IsRegistered(name string) bool

func NewQuadStoreReader

func NewQuadStoreReader(qs QuadStore) quad.ReadSkipCloser

NewResultReader creates a quad reader for a given QuadStore.

func NewResultReader

func NewResultReader(qs QuadStore, it Iterator) 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 NextLogIn

func NextLogIn(it Iterator)

func NextLogOut

func NextLogOut(it Iterator, ok bool) bool

func QuadStores

func QuadStores() []string

func RegisterQuadStore

func RegisterQuadStore(name string, register QuadStoreRegistration)

func RegisterWriter

func RegisterWriter(name string, newFunc NewQuadWriterFunc)

func ToKey

func ToKey(v Value) interface{}

ToKey prepares Value to be stored inside maps, calling Key() if necessary.

func UpgradeQuadStore

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

func WriterMethods

func WriterMethods() []string

Types

type ApplyMorphism

type ApplyMorphism func(QuadStore, Iterator) Iterator

ApplyMorphism is a curried function that can generates a new iterator based on some prior iterator.

type BatchWriter

type BatchWriter interface {
	quad.WriteCloser
	quad.BatchWriter
	Flush() error
}

func NewRemover

func NewRemover(qs QuadWriter) BatchWriter

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

func NewWriter

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 BulkLoader

type BulkLoader interface {
	// BulkLoad loads Quads from a quad.Unmarshaler in bulk to the QuadStore.
	// It returns ErrCannotBulkLoad if bulk loading is not possible. For example if
	// you cannot load in bulk to a non-empty database, and the db is non-empty.
	BulkLoad(quad.Reader) error
}

type Delta

type Delta struct {
	ID        PrimaryKey
	Quad      quad.Quad
	Action    Procedure
	Timestamp time.Time
}

type DeltaError

type DeltaError struct {
	Delta Delta
	Err   error
}

DeltaError records an error and the delta that caused it.

func (*DeltaError) Error

func (e *DeltaError) Error() string

type Description

type Description struct {
	UID       uint64         `json:",omitempty"`
	Name      string         `json:",omitempty"`
	Type      Type           `json:",omitempty"`
	Tags      []string       `json:",omitempty"`
	Size      int64          `json:",omitempty"`
	Direction quad.Direction `json:",omitempty"`
	Iterator  *Description   `json:",omitempty"`
	Iterators []Description  `json:",omitempty"`
}

type FixedIterator

type FixedIterator interface {
	Iterator
	Add(Value)
}

FixedIterator wraps iterators that are modifiable by addition of fixed value sets.

type Handle

type Handle struct {
	QuadStore
	QuadWriter
}

func (*Handle) Close

func (h *Handle) Close() error

type IgnoreOpts

type IgnoreOpts struct {
	IgnoreDup, IgnoreMissing bool
}

type InitStoreFunc

type InitStoreFunc func(string, Options) error

type IterateChain

type IterateChain struct {
	// contains filtered or unexported fields
}

IterateChain is a chain-enabled helper to setup iterator execution.

func Iterate

func Iterate(ctx context.Context, it Iterator) *IterateChain

Iterate is a set of helpers for iteration. Context may be used to cancel execution. Iterator will be optimized and closed after execution.

By default, iteration has no limit and includes sub-paths.

func (*IterateChain) All

func (c *IterateChain) All() ([]Value, error)

All will return all results of an iterator.

func (*IterateChain) AllValues

func (c *IterateChain) AllValues(qs QuadStore) ([]quad.Value, error)

AllValues is an analog of All, but it will additionally call NameOf for each graph.Value before returning the results slice.

func (*IterateChain) Count

func (c *IterateChain) Count() (int64, error)

All will return all results of an iterator.

func (*IterateChain) Each

func (c *IterateChain) Each(fnc func(Value)) error

Each will run a provided callback for each result of the iterator.

func (*IterateChain) EachValue

func (c *IterateChain) EachValue(qs QuadStore, fnc func(quad.Value)) error

EachValue is an analog of Each, but it will additionally call NameOf for each graph.Value before passing it to a callback.

func (*IterateChain) EachValuePair

func (c *IterateChain) EachValuePair(qs QuadStore, fnc func(Value, quad.Value)) error

EachValuePair is an analog of Each, but it will additionally call NameOf for each graph.Value before passing it to a callback. Original value will be passed as well.

func (*IterateChain) First

func (c *IterateChain) First() (Value, error)

First will return a first result of an iterator. It returns nil if iterator is empty.

func (*IterateChain) FirstValue

func (c *IterateChain) FirstValue(qs QuadStore) (quad.Value, error)

FirstValue is an analog of First, but it does lookup of a value in QuadStore.

func (*IterateChain) Limit

func (c *IterateChain) Limit(n int) *IterateChain

Limit limits a total number of results returned.

func (*IterateChain) On

func (c *IterateChain) On(qs QuadStore) *IterateChain

On sets a default quad store for iteration. If qs was set, it may be omitted in other functions.

func (*IterateChain) Paths

func (c *IterateChain) Paths(enable bool) *IterateChain

Paths switches iteration over sub-paths (with it.NextPath). Defaults to true.

func (*IterateChain) Send

func (c *IterateChain) Send(out chan<- Value) error

Send will send each result of the iterator to the provided channel.

Channel will NOT be closed when function returns.

func (*IterateChain) SendValues

func (c *IterateChain) SendValues(qs QuadStore, out chan<- quad.Value) error

SendValues is an analog of Send, but it will additionally call NameOf for each graph.Value before sending it to a channel.

func (*IterateChain) TagEach

func (c *IterateChain) TagEach(fnc func(map[string]Value)) error

TagEach will run a provided tag map callback for each result of the iterator.

func (*IterateChain) TagValues

func (c *IterateChain) TagValues(qs QuadStore, fnc func(map[string]quad.Value)) error

TagValues is an analog of TagEach, but it will additionally call NameOf for each graph.Value before passing the map to a callback.

func (*IterateChain) UnOptimized

func (c *IterateChain) UnOptimized() *IterateChain

UnOptimized disables iterator optimization.

type Iterator

type Iterator interface {
	Tagger() *Tagger

	// Fills a tag-to-result-value map.
	TagResults(map[string]Value)

	// Returns the current result.
	Result() Value

	// Next advances the iterator to the next value, which will then be available through
	// the Result method. It returns false if no further advancement is possible, or if an
	// error was encountered during iteration.  Err should be consulted to distinguish
	// between the two cases.
	Next() bool

	// These methods are the heart and soul of the iterator, as they constitute
	// the iteration interface.
	//
	// To get the full results of iteration, do the following:
	//
	//  for graph.Next(it) {
	//  	val := it.Result()
	//  	... do things with val.
	//  	for it.NextPath() {
	//  		... find other paths to iterate
	//  	}
	//  }
	//
	// All of them should set iterator.result to be the last returned value, to
	// make results work.
	//
	// NextPath() advances iterators that may have more than one valid result,
	// from the bottom up.
	NextPath() bool

	// Contains returns whether the value is within the set held by the iterator.
	Contains(Value) bool

	// Err returns any error that was encountered by the Iterator.
	Err() error

	// Start iteration from the beginning
	Reset()

	// Create a new iterator just like this one
	Clone() Iterator

	// These methods relate to choosing the right iterator, or optimizing an
	// iterator tree
	//
	// Stats() returns the relative costs of calling the iteration methods for
	// this iterator, as well as the size. Roughly, it will take NextCost * Size
	// "cost units" to get everything out of the iterator. This is a wibbly-wobbly
	// thing, and not exact, but a useful heuristic.
	Stats() IteratorStats

	// Helpful accessor for the number of things in the iterator. The first return
	// value is the size, and the second return value is whether that number is exact,
	// or a conservative estimate.
	Size() (int64, bool)

	// Returns a string relating to what the function of the iterator is. By
	// knowing the names of the iterators, we can devise optimization strategies.
	Type() Type

	// Optimizes an iterator. Can replace the iterator, or merely move things
	// around internally. if it chooses to replace it with a better iterator,
	// returns (the new iterator, true), if not, it returns (self, false).
	Optimize() (Iterator, bool)

	// Return a slice of the subiterators for this iterator.
	SubIterators() []Iterator

	// Return a string representation of the iterator.
	Describe() Description

	// Close the iterator and do internal cleanup.
	Close() error

	// UID returns the unique identifier of the iterator.
	UID() uint64
}

type IteratorStats

type IteratorStats struct {
	ContainsCost int64
	NextCost     int64
	Size         int64
	ExactSize    bool
	Next         int64
	Contains     int64
	ContainsNext int64
}

type Keyer deprecated

type Keyer interface {
	Key() interface{}
}

Keyer provides a method for comparing types that are not otherwise comparable. The Key method must return a dynamic type that is comparable according to the Go language specification. The returned value must be unique for each receiver value.

Deprecated: Value contains the same method now.

type Linkage

type Linkage struct {
	Dir   quad.Direction
	Value Value
}

Linkage is a union type representing a set of values established for a given quad direction.

type NewQuadWriterFunc

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

type NewStoreFunc

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

type NoNext

type NoNext interface {
	NoNext()
}

NoNext is an optional interface to signal that iterator should be Contain()'ed instead of Next()'ing if possible.

type Options

type Options map[string]interface{}

func (Options) BoolKey

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

func (Options) IntKey

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

func (Options) StringKey

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

type PreFetchedValue

type PreFetchedValue interface {
	Value
	NameOf() quad.Value
}

PreFetchedValue is an optional interface for graph.Value to indicate that quadstore has already loaded a value into memory.

func PreFetched

func PreFetched(v quad.Value) PreFetchedValue

type PrimaryKey

type PrimaryKey struct {
	// contains filtered or unexported fields
}

func NewSequentialKey

func NewSequentialKey(horizon int64) PrimaryKey

func NewUniqueKey

func NewUniqueKey(horizon string) PrimaryKey

func (*PrimaryKey) Int

func (p *PrimaryKey) Int() int64

func (PrimaryKey) MarshalJSON

func (p PrimaryKey) MarshalJSON() ([]byte, error)

func (*PrimaryKey) Next

func (p *PrimaryKey) Next() PrimaryKey

func (*PrimaryKey) String

func (p *PrimaryKey) String() string

func (*PrimaryKey) UnmarshalJSON

func (p *PrimaryKey) UnmarshalJSON(bytes []byte) error

type Procedure

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

The different types of actions a transaction can do.

func (Procedure) String

func (p Procedure) String() string

type QuadStore

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

	// Given an opaque token, returns the quad for that token from the store.
	Quad(Value) 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, Value) Iterator

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

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

	// Given a node ID, return the opaque token used by the QuadStore
	// to represent that id.
	ValueOf(quad.Value) Value

	// Given an opaque token, return the node that it represents.
	NameOf(Value) quad.Value

	// Returns the number of quads currently stored.
	Size() int64

	// The last replicated transaction ID that this quadstore has verified.
	Horizon() PrimaryKey

	// Creates a fixed iterator which can compare Values
	FixedIterator() FixedIterator

	// Optimize an iterator in the context of the quad store.
	// Suppose we have a better index for the passed tree; this
	// gives the QuadStore the opportunity to replace it
	// with a more efficient iterator.
	OptimizeIterator(it Iterator) (Iterator, bool)

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

	// Get the type of QuadStore
	//TODO replace this using reflection
	Type() string
}

func NewQuadStore

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

type QuadStoreRegistration

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

type QuadWriter

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.
	RemoveNode(quad.Value) error

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

func NewQuadWriter

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

type StatsContainer

type StatsContainer struct {
	UID  uint64
	Type Type
	IteratorStats
	SubIts []StatsContainer
}

func DumpStats

func DumpStats(it Iterator) StatsContainer

type Tagger

type Tagger struct {
	// contains filtered or unexported fields
}

func (*Tagger) Add

func (t *Tagger) Add(tag string)

Add a tag to the iterator.

func (*Tagger) AddFixed

func (t *Tagger) AddFixed(tag string, value Value)

func (*Tagger) CopyFrom

func (t *Tagger) CopyFrom(src Iterator)

func (*Tagger) CopyFromTagger

func (t *Tagger) CopyFromTagger(st *Tagger)

func (*Tagger) Fixed

func (t *Tagger) Fixed() map[string]Value

Fixed returns the fixed tags held in the tagger. The returned value must not be mutated.

func (*Tagger) Tags

func (t *Tagger) Tags() []string

Tags returns the tags held in the tagger. The returned value must not be mutated.

type Transaction

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

func NewTransaction() *Transaction

NewTransaction initialize a new transaction.

func (*Transaction) AddQuad

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

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 Type

type Type int

Type enumerates the set of Iterator types.

const (
	Invalid Type = iota
	All
	And
	Or
	HasA
	LinksTo
	Comparison
	Null
	Fixed
	Not
	Optional
	Materialize
	Unique
	Limit
	Skip
	Regex
	Count
	Recursive
)

These are the iterator types, defined as constants

func RegisterIterator

func RegisterIterator(name string) Type

RegisterIterator adds a new iterator type to the set of acceptable types, returning the registered Type. Calls to Register are idempotent and must be made prior to use of the iterator. The conventional approach for use is to include a call to Register in a package init() function, saving the Type to a private package var.

func (*Type) MarshalText

func (t *Type) MarshalText() (text []byte, err error)

func (Type) String

func (t Type) String() string

String returns a string representation of the Type.

func (*Type) UnmarshalText

func (t *Type) UnmarshalText(text []byte) error

type UpgradeStoreFunc

type UpgradeStoreFunc func(string, Options) error

type Value

type Value interface {
	Key() interface{}
}

Value defines an opaque "quad store value" type. However the backend wishes to implement it, a Value 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.

Directories

Path Synopsis
Package proto is a generated protocol buffer package.
Package proto is a generated protocol buffer package.

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