From 0d7e6dae96d949302350f534c12f3fac82e84f18 Mon Sep 17 00:00:00 2001
From: Daniel <dhaavi@users.noreply.github.com>
Date: Mon, 19 Oct 2020 10:54:55 +0200
Subject: [PATCH] Clarify and clean up record key functions

---
 database/interface_cache.go |  6 +++++-
 database/record/base.go     | 36 +++++++++++++++++++++++-------------
 database/record/record.go   |  5 ++---
 3 files changed, 30 insertions(+), 17 deletions(-)

diff --git a/database/interface_cache.go b/database/interface_cache.go
index 5858b61..ec2eb7c 100644
--- a/database/interface_cache.go
+++ b/database/interface_cache.go
@@ -159,7 +159,11 @@ func (i *Interface) checkCache(key string) record.Record {
 	return nil
 }
 
-// updateCache updates an entry in the
+// updateCache updates an entry in the interface cache. The given record may
+// not be locked, as updating the cache might write an (unrelated) evicted
+// record to the database in the process. If this happens while the
+// DelayedCacheWriter flushes the write cache with the same record present,
+// this will deadlock.
 func (i *Interface) updateCache(r record.Record, write bool, remove bool, ttl int64) (written bool) {
 	// Check if cache is in use.
 	if i.cache == nil {
diff --git a/database/record/base.go b/database/record/base.go
index 33f6d2f..54336cd 100644
--- a/database/record/base.go
+++ b/database/record/base.go
@@ -6,6 +6,7 @@ import (
 	"github.com/safing/portbase/container"
 	"github.com/safing/portbase/database/accessor"
 	"github.com/safing/portbase/formats/dsd"
+	"github.com/safing/portbase/log"
 )
 
 // Base provides a quick way to comply with the Model interface.
@@ -15,37 +16,46 @@ type Base struct {
 	meta   *Meta
 }
 
+// SetKey sets the key on the database record. The key may only be set once and
+// future calls to SetKey will be ignored. If you want to copy/move the record
+// to another database key, you will need to create a copy and assign a new key.
+// A key must be set before the record is used in any database operation.
+func (b *Base) SetKey(key string) {
+	if !b.KeyIsSet() {
+		b.dbName, b.dbKey = ParseKey(key)
+	} else {
+		log.Errorf("database: key is already set: tried to replace %q with %q", b.Key(), key)
+	}
+}
+
 // Key returns the key of the database record.
+// As the key must be set before any usage and can only be set once, this
+// function may be used without locking the record.
 func (b *Base) Key() string {
 	return b.dbName + ":" + b.dbKey
 }
 
 // KeyIsSet returns true if the database key is set.
+// As the key must be set before any usage and can only be set once, this
+// function may be used without locking the record.
 func (b *Base) KeyIsSet() bool {
-	return len(b.dbName) > 0 && len(b.dbKey) > 0
+	return b.dbName != ""
 }
 
 // DatabaseName returns the name of the database.
+// As the key must be set before any usage and can only be set once, this
+// function may be used without locking the record.
 func (b *Base) DatabaseName() string {
 	return b.dbName
 }
 
 // DatabaseKey returns the database key of the database record.
+// As the key must be set before any usage and can only be set once, this
+// function may be used without locking the record.
 func (b *Base) DatabaseKey() string {
 	return b.dbKey
 }
 
-// SetKey sets the key on the database record, it should only be called after loading the record. Use MoveTo to save the record with another key.
-func (b *Base) SetKey(key string) {
-	b.dbName, b.dbKey = ParseKey(key)
-}
-
-// MoveTo sets a new key for the record and resets all metadata, except for the secret and crownjewel status.
-func (b *Base) MoveTo(key string) {
-	b.SetKey(key)
-	b.meta.Reset()
-}
-
 // Meta returns the metadata object for this record.
 func (b *Base) Meta() *Meta {
 	return b.meta
@@ -59,7 +69,7 @@ func (b *Base) CreateMeta() {
 // UpdateMeta creates the metadata if it does not exist and updates it.
 func (b *Base) UpdateMeta() {
 	if b.meta == nil {
-		b.meta = &Meta{}
+		b.CreateMeta()
 	}
 	b.meta.Update()
 }
diff --git a/database/record/record.go b/database/record/record.go
index 850e65c..65808f2 100644
--- a/database/record/record.go
+++ b/database/record/record.go
@@ -6,13 +6,12 @@ import (
 
 // Record provides an interface for uniformally handling database records.
 type Record interface {
-	Key() string // test:config
+	SetKey(key string) // test:config
+	Key() string       // test:config
 	KeyIsSet() bool
 	DatabaseName() string // test
 	DatabaseKey() string  // config
 
-	SetKey(key string) // test:config
-	MoveTo(key string) // test:config
 	Meta() *Meta
 	SetMeta(meta *Meta)
 	CreateMeta()