dt

package module
v0.0.0-...-3af3e84 Latest Latest
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 Go to latest Published: Nov 16, 2021 License: BSD-2-Clause Imports: 7 Imported by: 0

README

dt: CRDT in Golang

  • GSset
  • GCounter
  • LWWReg
  • ORSet
  • Vector Clock

License

dt is developed under the BSD-2-Clause License.

Documentation

Index

Constants

View Source 
const DEFAULT_BIG_VCLOCK = 50
View Source 
const DEFAULT_OLD_VCLOCK = 86400
View Source 
const DEFAULT_SMALL_VCLOCK = 50
View Source 
const DEFAULT_YOUNG_VCLOCK = 20

Variables

This section is empty.

Functions

func GetBigVclock 

func GetBigVclock(prop map[string]int) int

func GetOldVclock 

func GetOldVclock(prop map[string]int) int

func GetParams 

func GetParams(d map[string]int, key string, default_value int) int

func GetSmallVclock 

func GetSmallVclock(prop map[string]int) int

func GetYoungVclock 

func GetYoungVclock(prop map[string]int) int

Types

type DVV 

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

Individual event with timestamp

func NewDVV 

func NewDVV() DVV

Instantiate a new DVV struct

func (DVV) Descends 

func (va DVV) Descends(vb DVV) bool

Return true if the vclock va is a direct descendant of vclock vb, else false.

func (DVV) Dominates 

func (va DVV) Dominates(vb DVV) bool

true if vclock va strictly dominates vclock vb. Note: ignores timestamps In riak it is possible to have vclocks that are identical except for timestamps. when two vclocks descend each other, but are not equal, they are concurrent. See source comment for more details.

func (*DVV) GetCounter 

func (v *DVV) GetCounter(id string) uint32

Get the counter value in a DVV set from node

func (*DVV) GetDot 

func (v *DVV) GetDot(id string) (*Dot, error)

Get the timestamp value in a DVV set from node

func (*DVV) GetTimestamp 

func (v *DVV) GetTimestamp(id string) (uint32, error)

Get the timestamp value in a DVV set from node

func (*DVV) Increment 

func (v *DVV) Increment(node string)

Increment vclock at Node

func (DVV) Len 

func (d DVV) Len() int

For sort. Returns length of vector of the dvv

func (DVV) Less 

func (d DVV) Less(i, j int) bool

For sort. Returns the result of compare two node

func (*DVV) Merge 

func (v *DVV) Merge(vclocks []DVV)

Combine all vclocks in the input list in to their least possible common descendant.

func (*DVV) Prune 

func (v *DVV) Prune(now uint32, props map[string]int)

Possibly shrink the size of a vclock, depending on current age and size.

func (DVV) Swap 

func (d DVV) Swap(i, j int)

For sort. Swap element

type Dot 

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

Timestamp of individual event

type GCounter 

type GCounter struct {
	Counters map[string]uint
}

func NewGCounter 

func NewGCounter() GCounter

Create a new gcounter

func (GCounter) AllNode 

func (counter GCounter) AllNode(counters []GCounter) []string

Returns the list of all nodes that have ever incremneted counter

func (GCounter) Equal 

func (counter_a GCounter) Equal(counter_b GCounter) bool

Compare two counter for equality

func (*GCounter) Increment 

func (counter *GCounter) Increment(node string)

increment counter for the node by 1

func (*GCounter) IncrementBy 

func (counter *GCounter) IncrementBy(node string, amount uint)

perform the increment

func (*GCounter) Merge 

func (counter_a *GCounter) Merge(counters []GCounter)

Combine all counters in the input list uinto a map

func (GCounter) Value 

func (counter GCounter) Value() uint

The single total value of a gcounter

type GSet 

type GSet struct {
	Set map[string]bool
}

func NewGSet 

func NewGSet() GSet

Create a new gset

func (*GSet) Add 

func (gset *GSet) Add(elem string)

append an element to the set

func (GSet) Equal 

func (gset_a GSet) Equal(gset_b GSet) bool

Compair Two set for equality

func (GSet) Exists 

func (gset GSet) Exists(elem string) bool

return true if the element exists in the set

func (*GSet) Values 

func (gset *GSet) Values() []string

Returns a set of value.

type LWWReg 

type LWWReg struct {
	Value     string
	Timestamp int64
}

func NewLWWReg 

func NewLWWReg() LWWReg

Create a new empty lwwreg

func (*LWWReg) Assign 

func (reg *LWWReg) Assign(value string)

Assign a value to the lwwreg associating the update with time ts

func (*LWWReg) AssignTS 

func (reg *LWWReg) AssignTS(value string, ts int64)

func (LWWReg) Equal 

func (reg_a LWWReg) Equal(reg_b LWWReg) bool

Are two lwwreg s structurally equal? this is not value equality. Two regsiters might represent the value armchair and not be equal(). Equality here is that both registers contain the same value and timestamp

func (*LWWReg) Merge 

func (reg_a *LWWReg) Merge(reg_b LWWReg)

Merge two lwwreg to a single lwwreg. this is the least upper bound function described in the literature

type ORSet 

type ORSet struct {
	Set map[string]Token
}

func NewOrset 

func NewOrset() ORSet

Create a new ORSet

func (ORSet) Lookup 

func (orset ORSet) Lookup(elem string) bool

func (ORSet) RemovedValue 

func (orset ORSet) RemovedValue() []string

Return values which has removed

func (ORSet) Token 

func (orset ORSet) Token(elem string) (Token, error)

func (ORSet) Value 

func (orset ORSet) Value() []string

Return values which hasn't removed only

type Token 

type Token struct {
	Tag       int
	IsRemoved bool
}

Source Files

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