cmap

Documentation

Overview

Package cmap provides concurrent map

Index

• Variables
• type ConcurrentMap
  • func New() ConcurrentMap
  • func (m ConcurrentMap) Count() int
  • func (m ConcurrentMap) Get(key string) (interface{}, bool)
  • func (m ConcurrentMap) GetShard(key string) *ConcurrentMapShared
  • func (m ConcurrentMap) Has(key string) bool
  • func (m ConcurrentMap) IsEmpty() bool
  • func (m ConcurrentMap) Items() map[string]interface{}
  • func (m ConcurrentMap) Iter() <-chan Tuple
  • func (m ConcurrentMap) IterBuffered() <-chan Tuple
  • func (m ConcurrentMap) IterCb(fn IterCb)
  • func (m ConcurrentMap) Keys() []string
  • func (m ConcurrentMap) MSet(data map[string]interface{})
  • func (m ConcurrentMap) MarshalJSON() ([]byte, error)
  • func (m ConcurrentMap) Pop(key string) (v interface{}, exists bool)
  • func (m ConcurrentMap) Remove(key string)
  • func (m ConcurrentMap) RemoveCb(key string, cb RemoveCb) bool
  • func (m ConcurrentMap) Set(key string, value interface{})
  • func (m ConcurrentMap) SetIfAbsent(key string, value interface{}) bool
  • func (m ConcurrentMap) Upsert(key string, value interface{}, cb UpsertCb) (res interface{})
• type ConcurrentMapShared
• type IterCb
• type RemoveCb
• type Tuple
• type UpsertCb

Variables

var SHARD_COUNT = 32

Types

type ConcurrentMap

type ConcurrentMap []*ConcurrentMapShared

A "thread" safe map of type string:Anything. To avoid lock bottlenecks this map is dived to several (SHARD_COUNT) map shards.

func New

func New() ConcurrentMap

Creates a new concurrent map.

func (ConcurrentMap) Count

func (m ConcurrentMap) Count() int

Returns the number of elements within the map.

func (ConcurrentMap) Get

func (m ConcurrentMap) Get(key string) (interface{}, bool)

Retrieves an element from map under given key.

func (ConcurrentMap) GetShard

func (m ConcurrentMap) GetShard(key string) *ConcurrentMapShared

Returns shard under given key

func (ConcurrentMap) Has

func (m ConcurrentMap) Has(key string) bool

Looks up an item under specified key

func (ConcurrentMap) IsEmpty

func (m ConcurrentMap) IsEmpty() bool

Checks if map is empty.

func (ConcurrentMap) Items

func (m ConcurrentMap) Items() map[string]interface{}

Returns all items as map[string]interface{}

func (ConcurrentMap) Iter

func (m ConcurrentMap) Iter() <-chan Tuple

Returns an iterator which could be used in a for range loop.

Deprecated: using IterBuffered() will get a better performance

func (ConcurrentMap) IterBuffered

func (m ConcurrentMap) IterBuffered() <-chan Tuple

Returns a buffered iterator which could be used in a for range loop.

func (ConcurrentMap) IterCb

func (m ConcurrentMap) IterCb(fn IterCb)

Callback based iterator, cheapest way to read all elements in a map.

func (ConcurrentMap) Keys

func (m ConcurrentMap) Keys() []string

Return all keys as []string

func (ConcurrentMap) MSet

func (m ConcurrentMap) MSet(data map[string]interface{})

func (ConcurrentMap) MarshalJSON

func (m ConcurrentMap) MarshalJSON() ([]byte, error)

Reviles ConcurrentMap "private" variables to json marshal.

func (ConcurrentMap) Pop

func (m ConcurrentMap) Pop(key string) (v interface{}, exists bool)

Removes an element from the map and returns it

func (ConcurrentMap) Remove

func (m ConcurrentMap) Remove(key string)

Removes an element from the map.

func (ConcurrentMap) RemoveCb

func (m ConcurrentMap) RemoveCb(key string, cb RemoveCb) bool

RemoveCb locks the shard containing the key, retrieves its current value and calls the callback with those params If callback returns true and element exists, it will remove it from the map Returns the value returned by the callback (even if element was not present in the map)

func (ConcurrentMap) Set

func (m ConcurrentMap) Set(key string, value interface{})

Sets the given value under the specified key.

func (ConcurrentMap) SetIfAbsent

func (m ConcurrentMap) SetIfAbsent(key string, value interface{}) bool

Sets the given value under the specified key if no value was associated with it.

func (ConcurrentMap) Upsert

func (m ConcurrentMap) Upsert(key string, value interface{}, cb UpsertCb) (res interface{})

Insert or Update - updates existing element or inserts a new one using UpsertCb

type ConcurrentMapShared

type ConcurrentMapShared struct {
	sync.RWMutex // Read Write mutex, guards access to internal map.
	// contains filtered or unexported fields
}

A "thread" safe string to anything map.

type IterCb

type IterCb func(key string, v interface{})

Iterator callback,called for every key,value found in maps. RLock is held for all calls for a given shard therefore callback sess consistent view of a shard, but not across the shards

type RemoveCb

type RemoveCb func(key string, v interface{}, exists bool) bool

RemoveCb is a callback executed in a map.RemoveCb() call, while Lock is held If returns true, the element will be removed from the map

type Tuple

type Tuple struct {
	Key string
	Val interface{}
}

Used by the Iter & IterBuffered functions to wrap two variables together over a channel,

type UpsertCb

type UpsertCb func(exist bool, valueInMap interface{}, newValue interface{}) interface{}

Callback to return new element to be inserted into the map It is called while lock is held, therefore it MUST NOT try to access other keys in same map, as it can lead to deadlock since Go sync.RWLock is not reentrant