252 lines
7.1 KiB
Go
252 lines
7.1 KiB
Go
/*
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*
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* Copyright 2021 gRPC authors.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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*/
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package resolver
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type addressMapEntry struct {
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addr Address
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value any
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}
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// AddressMap is a map of addresses to arbitrary values taking into account
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// Attributes. BalancerAttributes are ignored, as are Metadata and Type.
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// Multiple accesses may not be performed concurrently. Must be created via
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// NewAddressMap; do not construct directly.
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type AddressMap struct {
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// The underlying map is keyed by an Address with fields that we don't care
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// about being set to their zero values. The only fields that we care about
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// are `Addr`, `ServerName` and `Attributes`. Since we need to be able to
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// distinguish between addresses with same `Addr` and `ServerName`, but
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// different `Attributes`, we cannot store the `Attributes` in the map key.
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//
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// The comparison operation for structs work as follows:
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// Struct values are comparable if all their fields are comparable. Two
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// struct values are equal if their corresponding non-blank fields are equal.
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//
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// The value type of the map contains a slice of addresses which match the key
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// in their `Addr` and `ServerName` fields and contain the corresponding value
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// associated with them.
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m map[Address]addressMapEntryList
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}
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func toMapKey(addr *Address) Address {
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return Address{Addr: addr.Addr, ServerName: addr.ServerName}
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}
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type addressMapEntryList []*addressMapEntry
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// NewAddressMap creates a new AddressMap.
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func NewAddressMap() *AddressMap {
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return &AddressMap{m: make(map[Address]addressMapEntryList)}
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}
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// find returns the index of addr in the addressMapEntry slice, or -1 if not
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// present.
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func (l addressMapEntryList) find(addr Address) int {
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for i, entry := range l {
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// Attributes are the only thing to match on here, since `Addr` and
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// `ServerName` are already equal.
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if entry.addr.Attributes.Equal(addr.Attributes) {
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return i
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}
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}
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return -1
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}
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// Get returns the value for the address in the map, if present.
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func (a *AddressMap) Get(addr Address) (value any, ok bool) {
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addrKey := toMapKey(&addr)
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entryList := a.m[addrKey]
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if entry := entryList.find(addr); entry != -1 {
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return entryList[entry].value, true
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}
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return nil, false
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}
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// Set updates or adds the value to the address in the map.
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func (a *AddressMap) Set(addr Address, value any) {
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addrKey := toMapKey(&addr)
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entryList := a.m[addrKey]
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if entry := entryList.find(addr); entry != -1 {
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entryList[entry].value = value
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return
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}
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a.m[addrKey] = append(entryList, &addressMapEntry{addr: addr, value: value})
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}
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// Delete removes addr from the map.
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func (a *AddressMap) Delete(addr Address) {
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addrKey := toMapKey(&addr)
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entryList := a.m[addrKey]
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entry := entryList.find(addr)
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if entry == -1 {
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return
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}
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if len(entryList) == 1 {
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entryList = nil
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} else {
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copy(entryList[entry:], entryList[entry+1:])
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entryList = entryList[:len(entryList)-1]
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}
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a.m[addrKey] = entryList
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}
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// Len returns the number of entries in the map.
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func (a *AddressMap) Len() int {
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ret := 0
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for _, entryList := range a.m {
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ret += len(entryList)
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}
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return ret
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}
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// Keys returns a slice of all current map keys.
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func (a *AddressMap) Keys() []Address {
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ret := make([]Address, 0, a.Len())
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for _, entryList := range a.m {
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for _, entry := range entryList {
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ret = append(ret, entry.addr)
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}
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}
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return ret
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}
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// Values returns a slice of all current map values.
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func (a *AddressMap) Values() []any {
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ret := make([]any, 0, a.Len())
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for _, entryList := range a.m {
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for _, entry := range entryList {
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ret = append(ret, entry.value)
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}
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}
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return ret
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}
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type endpointNode struct {
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addrs map[string]struct{}
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}
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// Equal returns whether the unordered set of addrs are the same between the
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// endpoint nodes.
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func (en *endpointNode) Equal(en2 *endpointNode) bool {
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if len(en.addrs) != len(en2.addrs) {
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return false
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}
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for addr := range en.addrs {
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if _, ok := en2.addrs[addr]; !ok {
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return false
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}
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}
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return true
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}
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func toEndpointNode(endpoint Endpoint) endpointNode {
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en := make(map[string]struct{})
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for _, addr := range endpoint.Addresses {
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en[addr.Addr] = struct{}{}
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}
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return endpointNode{
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addrs: en,
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}
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}
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// EndpointMap is a map of endpoints to arbitrary values keyed on only the
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// unordered set of address strings within an endpoint. This map is not thread
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// safe, thus it is unsafe to access concurrently. Must be created via
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// NewEndpointMap; do not construct directly.
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type EndpointMap struct {
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endpoints map[*endpointNode]any
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}
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// NewEndpointMap creates a new EndpointMap.
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func NewEndpointMap() *EndpointMap {
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return &EndpointMap{
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endpoints: make(map[*endpointNode]any),
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}
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}
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// Get returns the value for the address in the map, if present.
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func (em *EndpointMap) Get(e Endpoint) (value any, ok bool) {
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en := toEndpointNode(e)
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if endpoint := em.find(en); endpoint != nil {
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return em.endpoints[endpoint], true
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}
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return nil, false
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}
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// Set updates or adds the value to the address in the map.
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func (em *EndpointMap) Set(e Endpoint, value any) {
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en := toEndpointNode(e)
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if endpoint := em.find(en); endpoint != nil {
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em.endpoints[endpoint] = value
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return
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}
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em.endpoints[&en] = value
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}
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// Len returns the number of entries in the map.
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func (em *EndpointMap) Len() int {
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return len(em.endpoints)
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}
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// Keys returns a slice of all current map keys, as endpoints specifying the
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// addresses present in the endpoint keys, in which uniqueness is determined by
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// the unordered set of addresses. Thus, endpoint information returned is not
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// the full endpoint data (drops duplicated addresses and attributes) but can be
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// used for EndpointMap accesses.
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func (em *EndpointMap) Keys() []Endpoint {
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ret := make([]Endpoint, 0, len(em.endpoints))
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for en := range em.endpoints {
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var endpoint Endpoint
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for addr := range en.addrs {
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endpoint.Addresses = append(endpoint.Addresses, Address{Addr: addr})
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}
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ret = append(ret, endpoint)
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}
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return ret
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}
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// Values returns a slice of all current map values.
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func (em *EndpointMap) Values() []any {
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ret := make([]any, 0, len(em.endpoints))
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for _, val := range em.endpoints {
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ret = append(ret, val)
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}
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return ret
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}
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// find returns a pointer to the endpoint node in em if the endpoint node is
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// already present. If not found, nil is returned. The comparisons are done on
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// the unordered set of addresses within an endpoint.
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func (em EndpointMap) find(e endpointNode) *endpointNode {
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for endpoint := range em.endpoints {
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if e.Equal(endpoint) {
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return endpoint
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}
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}
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return nil
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}
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// Delete removes the specified endpoint from the map.
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func (em *EndpointMap) Delete(e Endpoint) {
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en := toEndpointNode(e)
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if entry := em.find(en); entry != nil {
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delete(em.endpoints, entry)
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}
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}
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