gotosocial/vendor/codeberg.org/gruf/go-cache/v3/ttl/ttl.go

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package ttl
import (
"sync"
"time"
_ "unsafe"
"codeberg.org/gruf/go-maps"
)
// Entry represents an item in the cache, with it's currently calculated Expiry time.
type Entry[Key comparable, Value any] struct {
Key Key
Value Value
Expiry uint64
}
[feature] simpler cache size configuration (#2051) * add automatic cache max size generation based on ratios of a singular fixed memory target Signed-off-by: kim <grufwub@gmail.com> * remove now-unused cache max-size config variables Signed-off-by: kim <grufwub@gmail.com> * slight ratio tweak Signed-off-by: kim <grufwub@gmail.com> * remove unused visibility config var Signed-off-by: kim <grufwub@gmail.com> * add secret little ratio config trick Signed-off-by: kim <grufwub@gmail.com> * fixed a word Signed-off-by: kim <grufwub@gmail.com> * update cache library to remove use of TTL in result caches + slice cache Signed-off-by: kim <grufwub@gmail.com> * update other cache usages to use correct interface Signed-off-by: kim <grufwub@gmail.com> * update example config to explain the cache memory target Signed-off-by: kim <grufwub@gmail.com> * update env parsing test with new config values Signed-off-by: kim <grufwub@gmail.com> * do some ratio twiddling Signed-off-by: kim <grufwub@gmail.com> * add missing header * update envparsing with latest defaults Signed-off-by: kim <grufwub@gmail.com> * update size calculations to take into account result cache, simple cache and extra map overheads Signed-off-by: kim <grufwub@gmail.com> * tweak the ratios some more Signed-off-by: kim <grufwub@gmail.com> * more nan rampaging Signed-off-by: kim <grufwub@gmail.com> * fix envparsing script Signed-off-by: kim <grufwub@gmail.com> * update cache library, add sweep function to keep caches trim Signed-off-by: kim <grufwub@gmail.com> * sweep caches once a minute Signed-off-by: kim <grufwub@gmail.com> * add a regular job to sweep caches and keep under 80% utilisation Signed-off-by: kim <grufwub@gmail.com> * remove dead code Signed-off-by: kim <grufwub@gmail.com> * add new size library used to libraries section of readme Signed-off-by: kim <grufwub@gmail.com> * add better explanations for the mem-ratio numbers Signed-off-by: kim <grufwub@gmail.com> * update go-cache Signed-off-by: kim <grufwub@gmail.com> * library version bump Signed-off-by: kim <grufwub@gmail.com> * update cache.result{} size model estimation Signed-off-by: kim <grufwub@gmail.com> --------- Signed-off-by: kim <grufwub@gmail.com>
2023-08-03 09:34:35 +00:00
// Cache is the underlying TTLCache implementation, providing both the base Cache interface and unsafe access to underlying map to allow flexibility in building your own.
type Cache[Key comparable, Value any] struct {
// TTL is the cache item TTL.
TTL time.Duration
// Evict is the hook that is called when an item is evicted from the cache.
Evict func(Key, Value)
// Invalid is the hook that is called when an item's data in the cache is invalidated, includes Add/Set.
Invalid func(Key, Value)
// Cache is the underlying hashmap used for this cache.
Cache maps.LRUMap[Key, *Entry[Key, Value]]
// stop is the eviction routine cancel func.
stop func()
// pool is a memory pool of entry objects.
pool []*Entry[Key, Value]
// Embedded mutex.
sync.Mutex
}
// New returns a new initialized Cache with given initial length, maximum capacity and item TTL.
func New[K comparable, V any](len, cap int, ttl time.Duration) *Cache[K, V] {
c := new(Cache[K, V])
c.Init(len, cap, ttl)
return c
}
// Init will initialize this cache with given initial length, maximum capacity and item TTL.
func (c *Cache[K, V]) Init(len, cap int, ttl time.Duration) {
if ttl <= 0 {
// Default duration
ttl = time.Second * 5
}
c.TTL = ttl
c.SetEvictionCallback(nil)
c.SetInvalidateCallback(nil)
c.Cache.Init(len, cap)
}
// Start: implements cache.Cache's Start().
func (c *Cache[K, V]) Start(freq time.Duration) (ok bool) {
// Nothing to start
if freq <= 0 {
return false
}
// Safely start
c.Lock()
if ok = (c.stop == nil); ok {
// Not yet running, schedule us
c.stop = schedule(c.Sweep, freq)
}
// Done with lock
c.Unlock()
return
}
// Stop: implements cache.Cache's Stop().
func (c *Cache[K, V]) Stop() (ok bool) {
// Safely stop
c.Lock()
if ok = (c.stop != nil); ok {
// We're running, cancel evicts
c.stop()
c.stop = nil
}
// Done with lock
c.Unlock()
return
}
// Sweep attempts to evict expired items (with callback!) from cache.
func (c *Cache[K, V]) Sweep(_ time.Time) {
var (
// evicted key-values.
kvs []kv[K, V]
// hook func ptrs.
evict func(K, V)
// get current nanoseconds.
now = runtime_nanotime()
)
c.locked(func() {
if c.TTL <= 0 {
// sweep is
// disabled
return
}
// Sentinel value
after := -1
// The cache will be ordered by expiry date, we iterate until we reach the index of
// the youngest item that hsa expired, as all succeeding items will also be expired.
c.Cache.RangeIf(0, c.Cache.Len(), func(i int, _ K, item *Entry[K, V]) bool {
if now > item.Expiry {
after = i
// evict all older items
// than this (inclusive)
return false
}
// cont. loop.
return true
})
if after == -1 {
// No Truncation needed
return
}
// Set hook func ptr.
evict = c.Evict
// Truncate determined size.
sz := c.Cache.Len() - after
kvs = c.truncate(sz, evict)
})
if evict != nil {
for x := range kvs {
// Pass to eviction hook.
evict(kvs[x].K, kvs[x].V)
}
}
}
// SetEvictionCallback: implements cache.Cache's SetEvictionCallback().
func (c *Cache[K, V]) SetEvictionCallback(hook func(K, V)) {
c.locked(func() {
c.Evict = hook
})
}
// SetInvalidateCallback: implements cache.Cache's SetInvalidateCallback().
func (c *Cache[K, V]) SetInvalidateCallback(hook func(K, V)) {
c.locked(func() {
c.Invalid = hook
})
}
// SetTTL: implements cache.Cache's SetTTL().
func (c *Cache[K, V]) SetTTL(ttl time.Duration, update bool) {
c.locked(func() {
// Set updated TTL
diff := ttl - c.TTL
c.TTL = ttl
if update {
// Update existing cache entries with new expiry time
c.Cache.Range(0, c.Cache.Len(), func(i int, _ K, item *Entry[K, V]) {
item.Expiry += uint64(diff)
})
}
})
}
// Get: implements cache.Cache's Get().
func (c *Cache[K, V]) Get(key K) (V, bool) {
var (
// did exist in cache?
ok bool
// cached value.
v V
)
c.locked(func() {
var item *Entry[K, V]
// Check for item in cache
item, ok = c.Cache.Get(key)
if !ok {
return
}
// Update fetched's expiry
item.Expiry = c.expiry()
// Set value.
v = item.Value
})
return v, ok
}
// Add: implements cache.Cache's Add().
func (c *Cache[K, V]) Add(key K, value V) bool {
var (
// did exist in cache?
ok bool
// was entry evicted?
ev bool
// evicted key values.
evcK K
evcV V
// hook func ptrs.
evict func(K, V)
)
c.locked(func() {
// Check if in cache.
ok = c.Cache.Has(key)
if ok {
return
}
// Alloc new entry.
new := c.alloc()
new.Expiry = c.expiry()
new.Key = key
new.Value = value
// Add new entry to cache and catched any evicted item.
c.Cache.SetWithHook(key, new, func(_ K, item *Entry[K, V]) {
evcK = item.Key
evcV = item.Value
ev = true
c.free(item)
})
// Set hook func ptr.
evict = c.Evict
})
if ev && evict != nil {
// Pass to eviction hook.
evict(evcK, evcV)
}
return !ok
}
// Set: implements cache.Cache's Set().
func (c *Cache[K, V]) Set(key K, value V) {
var (
// did exist in cache?
ok bool
// was entry evicted?
ev bool
// old value.
oldV V
// evicted key values.
evcK K
evcV V
// hook func ptrs.
invalid func(K, V)
evict func(K, V)
)
c.locked(func() {
var item *Entry[K, V]
// Check for item in cache
item, ok = c.Cache.Get(key)
if ok {
// Set old value.
oldV = item.Value
// Update the existing item.
item.Expiry = c.expiry()
item.Value = value
} else {
// Alloc new entry.
new := c.alloc()
new.Expiry = c.expiry()
new.Key = key
new.Value = value
// Add new entry to cache and catched any evicted item.
c.Cache.SetWithHook(key, new, func(_ K, item *Entry[K, V]) {
evcK = item.Key
evcV = item.Value
ev = true
c.free(item)
})
}
// Set hook func ptrs.
invalid = c.Invalid
evict = c.Evict
})
if ok && invalid != nil {
// Pass to invalidate hook.
invalid(key, oldV)
}
if ev && evict != nil {
// Pass to eviction hook.
evict(evcK, evcV)
}
}
// CAS: implements cache.Cache's CAS().
func (c *Cache[K, V]) CAS(key K, old V, new V, cmp func(V, V) bool) bool {
var (
// did exist in cache?
ok bool
// swapped value.
oldV V
// hook func ptrs.
invalid func(K, V)
)
c.locked(func() {
var item *Entry[K, V]
// Check for item in cache
item, ok = c.Cache.Get(key)
if !ok {
return
}
// Perform the comparison
if !cmp(old, item.Value) {
return
}
// Set old value.
oldV = item.Value
// Update value + expiry.
item.Expiry = c.expiry()
item.Value = new
// Set hook func ptr.
invalid = c.Invalid
})
if ok && invalid != nil {
// Pass to invalidate hook.
invalid(key, oldV)
}
return ok
}
// Swap: implements cache.Cache's Swap().
func (c *Cache[K, V]) Swap(key K, swp V) V {
var (
// did exist in cache?
ok bool
// swapped value.
oldV V
// hook func ptrs.
invalid func(K, V)
)
c.locked(func() {
var item *Entry[K, V]
// Check for item in cache
item, ok = c.Cache.Get(key)
if !ok {
return
}
// Set old value.
oldV = item.Value
// Update value + expiry.
item.Expiry = c.expiry()
item.Value = swp
// Set hook func ptr.
invalid = c.Invalid
})
if ok && invalid != nil {
// Pass to invalidate hook.
invalid(key, oldV)
}
return oldV
}
// Has: implements cache.Cache's Has().
func (c *Cache[K, V]) Has(key K) (ok bool) {
c.locked(func() {
ok = c.Cache.Has(key)
})
return
}
// Invalidate: implements cache.Cache's Invalidate().
func (c *Cache[K, V]) Invalidate(key K) (ok bool) {
var (
// old value.
oldV V
// hook func ptrs.
invalid func(K, V)
)
c.locked(func() {
var item *Entry[K, V]
// Check for item in cache
item, ok = c.Cache.Get(key)
if !ok {
return
}
// Set old value.
oldV = item.Value
// Remove from cache map
_ = c.Cache.Delete(key)
// Free entry
c.free(item)
// Set hook func ptrs.
invalid = c.Invalid
})
if ok && invalid != nil {
// Pass to invalidate hook.
invalid(key, oldV)
}
return
}
// InvalidateAll: implements cache.Cache's InvalidateAll().
func (c *Cache[K, V]) InvalidateAll(keys ...K) (ok bool) {
var (
// invalidated kvs.
kvs []kv[K, V]
// hook func ptrs.
invalid func(K, V)
)
// Allocate a slice for invalidated.
kvs = make([]kv[K, V], 0, len(keys))
c.locked(func() {
for x := range keys {
var item *Entry[K, V]
// Check for item in cache
item, ok = c.Cache.Get(keys[x])
if !ok {
continue
}
// Append this old value to slice
kvs = append(kvs, kv[K, V]{
K: keys[x],
V: item.Value,
})
// Remove from cache map
_ = c.Cache.Delete(keys[x])
// Free entry
c.free(item)
}
// Set hook func ptrs.
invalid = c.Invalid
})
if invalid != nil {
for x := range kvs {
// Pass to invalidate hook.
invalid(kvs[x].K, kvs[x].V)
}
}
return
}
// Clear: implements cache.Cache's Clear().
func (c *Cache[K, V]) Clear() {
var (
// deleted key-values.
kvs []kv[K, V]
// hook func ptrs.
invalid func(K, V)
)
c.locked(func() {
// Set hook func ptr.
invalid = c.Invalid
// Truncate the entire cache length.
kvs = c.truncate(c.Cache.Len(), invalid)
})
if invalid != nil {
for x := range kvs {
// Pass to invalidate hook.
invalid(kvs[x].K, kvs[x].V)
}
}
}
// Len: implements cache.Cache's Len().
func (c *Cache[K, V]) Len() (l int) {
c.locked(func() { l = c.Cache.Len() })
return
}
// Cap: implements cache.Cache's Cap().
func (c *Cache[K, V]) Cap() (l int) {
c.locked(func() { l = c.Cache.Cap() })
return
}
// locked performs given function within mutex lock (NOTE: UNLOCK IS NOT DEFERRED).
func (c *Cache[K, V]) locked(fn func()) {
c.Lock()
fn()
c.Unlock()
}
// truncate will truncate the cache by given size, returning deleted items.
func (c *Cache[K, V]) truncate(sz int, hook func(K, V)) []kv[K, V] {
if hook == nil {
// No hook to execute, simply free all truncated entries.
c.Cache.Truncate(sz, func(_ K, e *Entry[K, V]) { c.free(e) })
return nil
}
// Allocate a slice for deleted k-v pairs.
deleted := make([]kv[K, V], 0, sz)
c.Cache.Truncate(sz, func(_ K, item *Entry[K, V]) {
// Store key-value pair for later access.
deleted = append(deleted, kv[K, V]{
K: item.Key,
V: item.Value,
})
// Free entry.
c.free(item)
})
return deleted
}
// alloc will acquire cache entry from pool, or allocate new.
func (c *Cache[K, V]) alloc() *Entry[K, V] {
if len(c.pool) == 0 {
return &Entry[K, V]{}
}
idx := len(c.pool) - 1
e := c.pool[idx]
c.pool = c.pool[:idx]
return e
}
// clone allocates a new Entry and copies all info from passed Entry.
func (c *Cache[K, V]) clone(e *Entry[K, V]) *Entry[K, V] {
e2 := c.alloc()
e2.Key = e.Key
e2.Value = e.Value
e2.Expiry = e.Expiry
return e2
}
// free will reset entry fields and place back in pool.
func (c *Cache[K, V]) free(e *Entry[K, V]) {
var (
zk K
zv V
)
e.Expiry = 0
e.Key = zk
e.Value = zv
c.pool = append(c.pool, e)
}
//go:linkname runtime_nanotime runtime.nanotime
func runtime_nanotime() uint64
// expiry returns an the next expiry time to use for an entry,
// which is equivalent to time.Now().Add(ttl), or zero if disabled.
func (c *Cache[K, V]) expiry() uint64 {
if ttl := c.TTL; ttl > 0 {
return runtime_nanotime() +
uint64(c.TTL)
}
return 0
}
type kv[K comparable, V any] struct {
K K
V V
}