1 files changed, 157 insertions, 0 deletions
diff --git a/internal/cache/account.go b/internal/cache/account.go
new file mode 100644
index 000000000..bb402d60f
--- /dev/null
+++ b/internal/cache/account.go
@@ -0,0 +1,157 @@
+package cache
+
+import (
+	"sync"
+
+	"github.com/ReneKroon/ttlcache"
+	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
+)
+
+// AccountCache is a wrapper around ttlcache.Cache to provide URL and URI lookups for gtsmodel.Account
+type AccountCache struct {
+	cache *ttlcache.Cache   // map of IDs -> cached accounts
+	urls  map[string]string // map of account URLs -> IDs
+	uris  map[string]string // map of account URIs -> IDs
+	mutex sync.Mutex
+}
+
+// NewAccountCache returns a new instantiated AccountCache object
+func NewAccountCache() *AccountCache {
+	c := AccountCache{
+		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{}) {
+		account := value.(*gtsmodel.Account)
+
+		c.mutex.Lock()
+		delete(c.urls, account.URL)
+		delete(c.uris, account.URI)
+		c.mutex.Unlock()
+	})
+
+	return &c
+}
+
+// GetByID attempts to fetch a account from the cache by its ID, you will receive a copy for thread-safety
+func (c *AccountCache) GetByID(id string) (*gtsmodel.Account, bool) {
+	c.mutex.Lock()
+	account, ok := c.getByID(id)
+	c.mutex.Unlock()
+	return account, ok
+}
+
+// GetByURL attempts to fetch a account from the cache by its URL, you will receive a copy for thread-safety
+func (c *AccountCache) GetByURL(url string) (*gtsmodel.Account, 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 account lookup
+	account, ok := c.getByID(id)
+	c.mutex.Unlock()
+	return account, ok
+}
+
+// GetByURI attempts to fetch a account from the cache by its URI, you will receive a copy for thread-safety
+func (c *AccountCache) GetByURI(uri string) (*gtsmodel.Account, 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 account lookup
+	account, ok := c.getByID(id)
+	c.mutex.Unlock()
+	return account, ok
+}
+
+// getByID performs an unsafe (no mutex locks) lookup of account by ID, returning a copy of account in cache
+func (c *AccountCache) getByID(id string) (*gtsmodel.Account, bool) {
+	v, ok := c.cache.Get(id)
+	if !ok {
+		return nil, false
+	}
+	return copyAccount(v.(*gtsmodel.Account)), true
+}
+
+// Put places a account in the cache, ensuring that the object place is a copy for thread-safety
+func (c *AccountCache) Put(account *gtsmodel.Account) {
+	if account == nil || account.ID == "" {
+		panic("invalid account")
+	}
+
+	c.mutex.Lock()
+	c.cache.Set(account.ID, copyAccount(account))
+	if account.URL != "" {
+		c.urls[account.URL] = account.ID
+	}
+	if account.URI != "" {
+		c.uris[account.URI] = account.ID
+	}
+	c.mutex.Unlock()
+}
+
+// copyAccount performs a surface-level copy of account, 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 copyAccount(account *gtsmodel.Account) *gtsmodel.Account {
+	return &gtsmodel.Account{
+		ID:                      account.ID,
+		Username:                account.Username,
+		Domain:                  account.Domain,
+		AvatarMediaAttachmentID: account.AvatarMediaAttachmentID,
+		AvatarMediaAttachment:   nil,
+		AvatarRemoteURL:         account.AvatarRemoteURL,
+		HeaderMediaAttachmentID: account.HeaderMediaAttachmentID,
+		HeaderMediaAttachment:   nil,
+		HeaderRemoteURL:         account.HeaderRemoteURL,
+		DisplayName:             account.DisplayName,
+		Fields:                  account.Fields,
+		Note:                    account.Note,
+		Memorial:                account.Memorial,
+		MovedToAccountID:        account.MovedToAccountID,
+		CreatedAt:               account.CreatedAt,
+		UpdatedAt:               account.UpdatedAt,
+		Bot:                     account.Bot,
+		Reason:                  account.Reason,
+		Locked:                  account.Locked,
+		Discoverable:            account.Discoverable,
+		Privacy:                 account.Privacy,
+		Sensitive:               account.Sensitive,
+		Language:                account.Language,
+		URI:                     account.URI,
+		URL:                     account.URL,
+		LastWebfingeredAt:       account.LastWebfingeredAt,
+		InboxURI:                account.InboxURI,
+		OutboxURI:               account.OutboxURI,
+		FollowingURI:            account.FollowingURI,
+		FollowersURI:            account.FollowersURI,
+		FeaturedCollectionURI:   account.FeaturedCollectionURI,
+		ActorType:               account.ActorType,
+		AlsoKnownAs:             account.AlsoKnownAs,
+		PrivateKey:              account.PrivateKey,
+		PublicKey:               account.PublicKey,
+		PublicKeyURI:            account.PublicKeyURI,
+		SensitizedAt:            account.SensitizedAt,
+		SilencedAt:              account.SilencedAt,
+		SuspendedAt:             account.SuspendedAt,
+		HideCollections:         account.HideCollections,
+		SuspensionOrigin:        account.SuspensionOrigin,
+	}
+}