Documentation
¶
Overview ¶
Package util contains utility classes for the graph storage.
GraphError ¶
Models a graph related error. Low-level errors should be wrapped in a GraphError before they are returned to a client.
IndexManager ¶
Manages the full text search index. The index supports simple word searches as well as phrase searches.
The index is a basically a key-value lookup which manages 2 types of entries:
Each node attribute value is split up into words. Each word gets an entry:
PrefixAttrWord + attr num + word (string) -> ids + pos (provides word and phrase lookup)
Each node attribute value is also converted into a MD5 sum which makes attribute value lookups very efficient:
PrefixAttrHash + attr num + hash (md5) -> ids (provides exact match lookup)
NamesManager ¶
Manages names of kinds, roles and attributes. Each stored name gets either a 16 or 32 bit (little endian) number assigned. The manager provides functions to lookup either the names or their numbers.
Index ¶
- Constants
- Variables
- type GraphError
- type IndexManager
- func (im *IndexManager) Count(attr, word string) (int, error)
- func (im *IndexManager) Deindex(key string, obj map[string]string) error
- func (im *IndexManager) Index(key string, obj map[string]string) error
- func (im *IndexManager) LookupPhrase(attr, phrase string) ([]string, error)
- func (im *IndexManager) LookupValue(attr, value string) ([]string, error)
- func (im *IndexManager) LookupWord(attr, word string) (map[string][]uint64, error)
- func (im *IndexManager) Reindex(key string, newObj map[string]string, oldObj map[string]string) error
- func (im *IndexManager) String() string
- type NamesManager
Constants ¶
const MaxKeysetSize = 1000
MaxKeysetSize is the maximum number of keys for a single word lookup.
const Prefix16Bit = "\x01"
Prefix16Bit is the prefix for 16 bit kind related entries
const Prefix32Bit = "\x02"
Prefix32Bit is the prefix for attribute related entries
const PrefixAttrHash = "\x01"
PrefixAttrHash is the prefix used for hashes of attribute values
const PrefixAttrWord = "\x01"
PrefixAttrWord is the prefix used for word index entries
const PrefixCode = "\x00"
PrefixCode is the prefix for entries storing codes
const PrefixCounter = "\x00"
PrefixCounter is the prefix for counter entries
const PrefixName = "\x01"
PrefixName is the prefix for entries storing names
Variables ¶
var ( ErrOpening = errors.New("Failed to open graph storage") ErrFlushing = errors.New("Failed to flush changes") ErrRollback = errors.New("Failed to rollback changes") ErrClosing = errors.New("Failed to close graph storage") ErrAccessComponent = errors.New("Failed to access graph storage component") ErrReadOnly = errors.New("Failed write to readonly storage") )
Graph storage related error types
var ( ErrInvalidData = errors.New("Invalid data") ErrIndexError = errors.New("Index error") ErrReading = errors.New("Could not read graph information") ErrWriting = errors.New("Could not write graph information") ErrRule = errors.New("Graph rule error") )
Graph related error types
var CaseSensitiveWordIndex = false
CaseSensitiveWordIndex is a flag to indicate if the index should be case sensitive.
Functions ¶
This section is empty.
Types ¶
type GraphError ¶
type GraphError struct {
Type error // Error type (to be used for equal checks)
Detail string // Details of this error
}
GraphError is a graph related error
func (*GraphError) Error ¶
func (ge *GraphError) Error() string
Error returns a human-readable string representation of this error.
type IndexManager ¶
type IndexManager struct {
// contains filtered or unexported fields
}
IndexManager data structure
func NewIndexManager ¶
func NewIndexManager(htree *hash.HTree) *IndexManager
NewIndexManager creates a new index manager instance.
func (*IndexManager) Count ¶
func (im *IndexManager) Count(attr, word string) (int, error)
Count returns the number of found nodes for a given word in a given attribute.
func (*IndexManager) Deindex ¶
func (im *IndexManager) Deindex(key string, obj map[string]string) error
Deindex deindexes (removes) a given object.
func (*IndexManager) Index ¶
func (im *IndexManager) Index(key string, obj map[string]string) error
Index indexes (inserts) a given object.
func (*IndexManager) LookupPhrase ¶
func (im *IndexManager) LookupPhrase(attr, phrase string) ([]string, error)
LookupPhrase finds all nodes where an attribute contains a certain phrase. This call returns a list of node keys which contain the phrase at least once.
func (*IndexManager) LookupValue ¶
func (im *IndexManager) LookupValue(attr, value string) ([]string, error)
LookupValue finds all nodes where an attribute has a certain value. This call returns a list of node keys.
func (*IndexManager) LookupWord ¶
func (im *IndexManager) LookupWord(attr, word string) (map[string][]uint64, error)
LookupWord finds all nodes where an attribute contains a certain word. This call returns a map which maps node key to a list of word positions.
func (*IndexManager) Reindex ¶
func (im *IndexManager) Reindex(key string, newObj map[string]string, oldObj map[string]string) error
Reindex reindexes (updates) a given object.
func (*IndexManager) String ¶
func (im *IndexManager) String() string
String returns a string representation of this index manager.
type NamesManager ¶
type NamesManager struct {
// contains filtered or unexported fields
}
NamesManager data structure
func NewNamesManager ¶
func NewNamesManager(nameDB map[string]string) *NamesManager
NewNamesManager creates a new names manager instance.
func (*NamesManager) Decode16 ¶
func (gs *NamesManager) Decode16(val string) string
Decode16 decodes a given 16 bit string to a value.
func (*NamesManager) Decode32 ¶
func (gs *NamesManager) Decode32(val string) string
Decode32 decodes a given 32 bit string to a value.
Source Files