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package cache
import (
"sync"
"github.com/ReneKroon/ttlcache"
"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
)
// statusCache is a wrapper around ttlcache.Cache to provide URL and URI lookups for gtsmodel.Status
type StatusCache struct {
cache *ttlcache.Cache // map of IDs -> cached statuses
urls map[string]string // map of status URLs -> IDs
uris map[string]string // map of status URIs -> IDs
mutex sync.Mutex
}
// newStatusCache returns a new instantiated statusCache object
func NewStatusCache() *StatusCache {
c := StatusCache{
cache: ttlcache.NewCache(),
urls: make(map[string]string, 100),
uris: make(map[string]string, 100),
mutex: sync.Mutex{},
}
// Set callback to purge lookup maps on expiration
c.cache.SetExpirationCallback(func(key string, value interface{}) {
status := value.(*gtsmodel.Status)
c.mutex.Lock()
delete(c.urls, status.URL)
delete(c.uris, status.URI)
c.mutex.Unlock()
})
return &c
}
// GetByID attempts to fetch a status from the cache by its ID, you will receive a copy for thread-safety
func (c *StatusCache) GetByID(id string) (*gtsmodel.Status, bool) {
c.mutex.Lock()
status, ok := c.getByID(id)
c.mutex.Unlock()
return status, ok
}
// GetByURL attempts to fetch a status from the cache by its URL, you will receive a copy for thread-safety
func (c *StatusCache) GetByURL(url string) (*gtsmodel.Status, bool) {
// Perform safe ID lookup
c.mutex.Lock()
id, ok := c.urls[url]
// Not found, unlock early
if !ok {
c.mutex.Unlock()
return nil, false
}
// Attempt status lookup
status, ok := c.getByID(id)
c.mutex.Unlock()
return status, ok
}
// GetByURI attempts to fetch a status from the cache by its URI, you will receive a copy for thread-safety
func (c *StatusCache) GetByURI(uri string) (*gtsmodel.Status, bool) {
// Perform safe ID lookup
c.mutex.Lock()
id, ok := c.uris[uri]
// Not found, unlock early
if !ok {
c.mutex.Unlock()
return nil, false
}
// Attempt status lookup
status, ok := c.getByID(id)
c.mutex.Unlock()
return status, ok
}
// getByID performs an unsafe (no mutex locks) lookup of status by ID, returning a copy of status in cache
func (c *StatusCache) getByID(id string) (*gtsmodel.Status, bool) {
v, ok := c.cache.Get(id)
if !ok {
return nil, false
}
return copyStatus(v.(*gtsmodel.Status)), true
}
// Put places a status in the cache, ensuring that the object place is a copy for thread-safety
func (c *StatusCache) Put(status *gtsmodel.Status) {
if status == nil || status.ID == "" {
panic("invalid status")
}
c.mutex.Lock()
c.cache.Set(status.ID, copyStatus(status))
if status.URL != "" {
c.urls[status.URL] = status.ID
}
if status.URI != "" {
c.uris[status.URI] = status.ID
}
c.mutex.Unlock()
}
// copyStatus performs a surface-level copy of status, only keeping attached IDs intact, not the objects.
// due to all the data being copied being 99% primitive types or strings (which are immutable and passed by ptr)
// this should be a relatively cheap process
func copyStatus(status *gtsmodel.Status) *gtsmodel.Status {
return >smodel.Status{
ID: status.ID,
URI: status.URI,
URL: status.URL,
Content: status.Content,
AttachmentIDs: status.AttachmentIDs,
Attachments: nil,
TagIDs: status.TagIDs,
Tags: nil,
MentionIDs: status.MentionIDs,
Mentions: nil,
EmojiIDs: status.EmojiIDs,
Emojis: nil,
CreatedAt: status.CreatedAt,
UpdatedAt: status.UpdatedAt,
Local: status.Local,
AccountID: status.AccountID,
Account: nil,
AccountURI: status.AccountURI,
InReplyToID: status.InReplyToID,
InReplyTo: nil,
InReplyToURI: status.InReplyToURI,
InReplyToAccountID: status.InReplyToAccountID,
InReplyToAccount: nil,
BoostOfID: status.BoostOfID,
BoostOf: nil,
BoostOfAccountID: status.BoostOfAccountID,
BoostOfAccount: nil,
ContentWarning: status.ContentWarning,
Visibility: status.Visibility,
Sensitive: status.Sensitive,
Language: status.Language,
CreatedWithApplicationID: status.CreatedWithApplicationID,
Federated: status.Federated,
Boostable: status.Boostable,
Replyable: status.Replyable,
Likeable: status.Likeable,
ActivityStreamsType: status.ActivityStreamsType,
Text: status.Text,
Pinned: status.Pinned,
}
}
|
