mirror of https://github.com/ergochat/ergo.git
94 lines
2.0 KiB
Go
94 lines
2.0 KiB
Go
// Copyright (c) 2012-2014 Jeremy Latt
|
|
// Copyright (c) 2016 Daniel Oaks <daniel@danieloaks.net>
|
|
// released under the MIT license
|
|
|
|
package irc
|
|
|
|
import (
|
|
"sync"
|
|
)
|
|
|
|
// WhoWasList holds our list of prior clients (for use with the WHOWAS command).
|
|
type WhoWasList struct {
|
|
buffer []WhoWas
|
|
// three possible states:
|
|
// empty: start == end == -1
|
|
// partially full: start != end
|
|
// full: start == end > 0
|
|
// if entries exist, they go from `start` to `(end - 1) % length`
|
|
start int
|
|
end int
|
|
|
|
accessMutex sync.RWMutex // tier 1
|
|
}
|
|
|
|
// NewWhoWasList returns a new WhoWasList
|
|
func (list *WhoWasList) Initialize(size int) {
|
|
list.buffer = make([]WhoWas, size)
|
|
list.start = -1
|
|
list.end = -1
|
|
}
|
|
|
|
// Append adds an entry to the WhoWasList.
|
|
func (list *WhoWasList) Append(whowas WhoWas) {
|
|
list.accessMutex.Lock()
|
|
defer list.accessMutex.Unlock()
|
|
|
|
if len(list.buffer) == 0 {
|
|
return
|
|
}
|
|
|
|
var pos int
|
|
if list.start == -1 { // empty
|
|
pos = 0
|
|
list.start = 0
|
|
list.end = 1
|
|
} else if list.start != list.end { // partially full
|
|
pos = list.end
|
|
list.end = (list.end + 1) % len(list.buffer)
|
|
} else if list.start == list.end { // full
|
|
pos = list.end
|
|
list.end = (list.end + 1) % len(list.buffer)
|
|
list.start = list.end // advance start as well, overwriting first entry
|
|
}
|
|
|
|
list.buffer[pos] = whowas
|
|
}
|
|
|
|
// Find tries to find an entry in our WhoWasList with the given details.
|
|
func (list *WhoWasList) Find(nickname string, limit int) (results []WhoWas) {
|
|
casefoldedNickname, err := CasefoldName(nickname)
|
|
if err != nil {
|
|
return
|
|
}
|
|
|
|
list.accessMutex.RLock()
|
|
defer list.accessMutex.RUnlock()
|
|
|
|
if list.start == -1 {
|
|
return
|
|
}
|
|
// iterate backwards through the ring buffer
|
|
pos := list.prev(list.end)
|
|
for limit == 0 || len(results) < limit {
|
|
if casefoldedNickname == list.buffer[pos].nickCasefolded {
|
|
results = append(results, list.buffer[pos])
|
|
}
|
|
if pos == list.start {
|
|
break
|
|
}
|
|
pos = list.prev(pos)
|
|
}
|
|
|
|
return
|
|
}
|
|
|
|
func (list *WhoWasList) prev(index int) int {
|
|
switch index {
|
|
case 0:
|
|
return len(list.buffer) - 1
|
|
default:
|
|
return index - 1
|
|
}
|
|
}
|