code review fixes and a little bit of new functionality

docs/API.md

@@ -414,11 +414,11 @@ A group topic is created by sending a `{sub}` message with the topic field set t
 
 A `channel` topic is different from the non-channel group topic in the following ways:
 
- * Channel-enabled topic is created by sending `{sub topic="nch"}`. Sending `{sub topic="new"}` will create a group topic without enabling channel functionality.
+ * Channel topic is created by sending `{sub topic="nch"}`. Sending `{sub topic="new"}` will create a group topic without enabling channel functionality.
  * Sending `{sub topic="chnAbC123"}` will create a `reader` subscription to a channel. A non-channel topic will reject such subscription request.
  * When searching for topics using [`fnd`](#fnd-and-tags-finding-users-and-topics), channels will show addresses with `chn` prefixes, non-channel topic will show with `grp` prefixes.
  * Default permissions for a channel and non-channel group topics are different: channel group topic grants no permissions at all.
- * A subscriber joining or leaving the topic generates a `{pres}` message to all other subscribers who are currently in the joined state with the topic and have appropriate permissions. Reader joining or leaving the channel generates no `{pres}` message.
+ * A subscriber joining or leaving the topic (regular or channel-enabled) generates a `{pres}` message to all other subscribers who are currently in the joined state with the topic and have appropriate permissions. Reader joining or leaving the channel generates no `{pres}` message.
 
 ### `sys` Topic
 

server/db/mongodb/adapter.go

@@ -1271,7 +1271,7 @@ func (a *adapter) TopicsForUser(uid t.Uid, keepDeleted bool, opts *t.QueryOpt) (
 			// grp subscription
 		} else {
 			// Convert channel names to topic names.
-			tname = t.GrpFromChn(tname)
+			tname = t.ChnToGrp(tname)
 			topq = append(topq, tname)
 		}
 		sub.Private = unmarshalBsonD(sub.Private)

server/db/mysql/adapter.go

@@ -1133,7 +1133,7 @@ func (a *adapter) UserUnreadCount(uid t.Uid) (int, error) {
 
 func (a *adapter) topicCreate(tx *sqlx.Tx, topic *t.Topic) error {
 	_, err := tx.Exec("INSERT INTO topics(createdat,updatedat,touchedat,state,name,usebt,owner,access,public,tags) "+
-		"VALUES(?,?,?,?,?,?,?,?,?)",
+		"VALUES(?,?,?,?,?,?,?,?,?,?)",
 		topic.CreatedAt, topic.UpdatedAt, topic.TouchedAt, topic.State, topic.Id, topic.UseBt,
 		store.DecodeUid(t.ParseUid(topic.Owner)), topic.Access, toJSON(topic.Public), topic.Tags)
 	if err != nil {
@@ -1317,7 +1317,7 @@ func (a *adapter) TopicsForUser(uid t.Uid, keepDeleted bool, opts *t.QueryOpt) (
 			// grp subscription
 		} else {
 			// Convert channel names to topic names.
-			tname = t.GrpFromChn(tname)
+			tname = t.ChnToGrp(tname)
 			topq = append(topq, tname)
 		}
 		sub.Private = fromJSON(sub.Private)
@@ -2004,7 +2004,7 @@ func (a *adapter) FindTopics(req [][]string, opt []string) ([]t.Subscription, er
 		}
 
 		if isChan != 0 {
-			sub.Topic = t.ChnFromGrp(sub.Topic)
+			sub.Topic = t.GrpToChn(sub.Topic)
 		}
 		sub.SetPublic(fromJSON(public))
 		sub.SetDefaultAccess(access.Auth, access.Anon)

server/db/rethinkdb/schema.md

@@ -14,7 +14,8 @@ Fields:
 * `Access` user's default access level for peer-to-peer topics
  * `Auth`, `Anon` default permissions for authenticated and anonymous users
 * `Public` application-defined data
-* `State` currently unused
+* `State` state of the user: normal, disabled, deleted
+* `StateAt` timestamp when the state was last updated or NULL
 * `LastSeen` timestamp when the user was last online
 * `UserAgent` client User-Agent used when last online
 * `Tags` unique strings for user discovery
@@ -99,10 +100,10 @@ Fields:
   * `Auth`, `Anon` permissions for authenticated and anonymous users respectively
  * `Owner` ID of the user who owns the topic
  * `Public` application-defined data
- * `State` currently unused
+ * `State` state of the topic: normal, disabled, deleted
  * `SeqId` sequential ID of the last message
  * `DelId` topic-sequential ID of the deletion operation
- * `UseBt` currently unused
+ * `UseBt` indicator that channel functionality is enabled in the topic
 
 Indexes:
 * `Id` primary key
@@ -328,4 +329,4 @@ Sample:
   "UpdatedAt": Sun Jun 10 2018 16:38:45 GMT+00:00 ,
   "User":  "7j-RR1V7O3Y"
 }
-```
+```

server/topic.go

@@ -12,6 +12,7 @@ import (
 	"errors"
 	"log"
 	"sort"
+	"strings"
 	"sync/atomic"
 	"time"
 
@@ -1011,13 +1012,11 @@ func (t *Topic) subscriptionReply(h *Hub, join *sessionJoin) error {
 	var err error
 	var changed bool
 	// Create new subscription or modify an existing one.
-	if changed, err = t.thisUserSub(h, join.sess, asUid, asLvl, join.pkt.Id, mode, private); err != nil {
+	if changed, err = t.thisUserSub(h, join, asUid, mode, private); err != nil {
 		return err
 	}
 
-	toriginal := t.original(asUid)
 	params := map[string]interface{}{}
-
 	if changed {
 		pud := t.perUser[asUid]
 		// Report back the assigned access mode.
@@ -1027,6 +1026,8 @@ func (t *Topic) subscriptionReply(h *Hub, join *sessionJoin) error {
 			Mode:  (pud.modeGiven & pud.modeWant).String()}
 	}
 
+	toriginal := t.original(asUid)
+
 	// When a group topic is created, it's given a temporary name by the client.
 	// Then this name changes. Report back the original name here.
 	if msgsub.Created && join.pkt.Original != toriginal {
@@ -1045,29 +1046,32 @@ func (t *Topic) subscriptionReply(h *Hub, join *sessionJoin) error {
 
 // User requests or updates a self-subscription to a topic. Called as a
 // result of {sub} or {meta set=sub}.
-// Returns changed == true if user's accessmode has changed.
+// Returns changed == true if user's access mode has changed.
 //
-//	h							- hub
-//	sess					- originating session
-//	asUid					- id of the user making the request
-//	asLvl					- access level of the user making the request
-//	pktID					- id of {sub} or {set} packet
-//	want					- requested access mode
-//	private				- private value to assign to the subscription
-//	background   	- presence notifications are deferred
-//	sessOverrides - session param overrides
+//	h				- hub
+//	sess			- originating session
+//	asUid			- id of the user making the request
+//	asLvl			- access level of the user making the request
+//	want			- requested access mode
+//	private			- private value to assign to the subscription
+//	background		- presence notifications are deferred
+//	sessOverrides	- session param overrides
 //
 // Handle these cases:
-// A. User is trying to subscribe for the first time (no subscription)
-// B. User is already subscribed, just joining without changing anything
-// C. User is responding to an earlier invite (modeWant was "N" in subscription)
-// D. User is already subscribed, changing modeWant
-// E. User is accepting ownership transfer (requesting ownership transfer is not permitted)
-func (t *Topic) thisUserSub(h *Hub, sess *Session, asUid types.Uid, asLvl auth.Level,
-	pktID, want string, private interface{}) (bool, error) {
+// A. User is trying to subscribe for the first time (no subscription).
+// B. User is already subscribed, just joining without changing anything.
+// C. User is responding to an earlier invite (modeWant was "N" in subscription).
+// D. User is already subscribed, changing modeWant.
+// E. User is accepting ownership transfer (requesting ownership transfer is not permitted).
+// In case of a group topic the user may be a reader or a full subscriber.
+func (t *Topic) thisUserSub(h *Hub, join *sessionJoin, asUid types.Uid, want string,
+	private interface{}) (bool, error) {
 
 	now := types.TimeNow()
-	toriginal := t.original(asUid)
+
+	sess := join.sess
+	pktID := join.pkt.Id
+	asLvl := auth.Level(join.pkt.AuthLvl)
 
 	var changed bool
 
@@ -1079,11 +1083,13 @@ func (t *Topic) thisUserSub(h *Hub, sess *Session, asUid types.Uid, asLvl auth.L
 	modeWant := types.ModeUnset
 	if want != "" {
 		if err := modeWant.UnmarshalText([]byte(want)); err != nil {
-			sess.queueOut(ErrMalformed(pktID, toriginal, now))
+			sess.queueOut(ErrMalformed(pktID, join.pkt.Original, now))
 			return changed, err
 		}
 	}
 
+	toriginal := t.original(asUid)
+
 	// Check if it's an attempt at a new subscription to the topic.
 	// It could be an actual subscription (IsJoiner() == true) or a ban (IsJoiner() == false)
 	userData, existingSub := t.perUser[asUid]