state: Minor Messages() fix

This commit fixes Messages() not returning the full messages list if the
state has kept track of some few messages from before.

api/message.go

@@ -14,11 +14,12 @@ import (
 )
 
 const (
-	// the limit of max messages per request, as imposed by Discord
-	maxMessageFetchLimit = 100
-	// maxMessageDeleteLimit is the limit of max message that can be deleted
+	// MaxMessageFetchLimit is the limit of max messages per request, as imposed
+	// by Discord.
+	MaxMessageFetchLimit = 100
+	// MaxMessageDeleteLimit is the limit of max message that can be deleted
 	// per bulk delete request, as imposed by Discord.
-	maxMessageDeleteLimit = 100
+	MaxMessageDeleteLimit = 100
 )
 
 // Messages returns a slice filled with the most recent messages sent in the
@@ -62,7 +63,7 @@ func (c *Client) MessagesBefore(
 
 	msgs := make([]discord.Message, 0, limit)
 
-	fetch := uint(maxMessageFetchLimit)
+	fetch := uint(MaxMessageFetchLimit)
 
 	// Check if we are truly fetching unlimited messages to avoid confusion
 	// later on, if the limit reaches 0.
@@ -72,8 +73,8 @@ func (c *Client) MessagesBefore(
 		if limit > 0 {
 			// Only fetch as much as we need. Since limit gradually decreases,
 			// we only need to fetch intmath.Min(fetch, limit).
-			fetch = uint(intmath.Min(maxMessageFetchLimit, int(limit)))
-			limit -= maxMessageFetchLimit
+			fetch = uint(intmath.Min(MaxMessageFetchLimit, int(limit)))
+			limit -= MaxMessageFetchLimit
 		}
 
 		m, err := c.messagesRange(channelID, before, 0, 0, fetch)
@@ -83,7 +84,7 @@ func (c *Client) MessagesBefore(
 		// Append the older messages into the list of newer messages.
 		msgs = append(msgs, m...)
 
-		if len(m) < maxMessageFetchLimit {
+		if len(m) < MaxMessageFetchLimit {
 			break
 		}
 
@@ -119,7 +120,7 @@ func (c *Client) MessagesAfter(
 
 	var msgs []discord.Message
 
-	fetch := uint(maxMessageFetchLimit)
+	fetch := uint(MaxMessageFetchLimit)
 
 	// Check if we are truly fetching unlimited messages to avoid confusion
 	// later on, if the limit reaches 0.
@@ -129,8 +130,8 @@ func (c *Client) MessagesAfter(
 		if limit > 0 {
 			// Only fetch as much as we need. Since limit gradually decreases,
 			// we only need to fetch intmath.Min(fetch, limit).
-			fetch = uint(intmath.Min(maxMessageFetchLimit, int(limit)))
-			limit -= maxMessageFetchLimit
+			fetch = uint(intmath.Min(MaxMessageFetchLimit, int(limit)))
+			limit -= MaxMessageFetchLimit
 		}
 
 		m, err := c.messagesRange(channelID, 0, after, 0, fetch)
@@ -140,7 +141,7 @@ func (c *Client) MessagesAfter(
 		// Prepend the older messages into the newly-fetched messages list.
 		msgs = append(m, msgs...)
 
-		if len(m) < maxMessageFetchLimit {
+		if len(m) < MaxMessageFetchLimit {
 			break
 		}
 
@@ -441,14 +442,14 @@ func (c *Client) DeleteMessages(
 		return nil
 	case len(messageIDs) == 1:
 		return c.DeleteMessage(channelID, messageIDs[0], reason)
-	case len(messageIDs) <= maxMessageDeleteLimit: // Fast path
+	case len(messageIDs) <= MaxMessageDeleteLimit: // Fast path
 		return c.deleteMessages(channelID, messageIDs, reason)
 	}
 
 	// If the number of messages to be deleted exceeds the amount discord is willing
 	// to accept at one time then batches of messages will be deleted
-	for start := 0; start < len(messageIDs); start += maxMessageDeleteLimit {
-		end := intmath.Min(len(messageIDs), start+maxMessageDeleteLimit)
+	for start := 0; start < len(messageIDs); start += MaxMessageDeleteLimit {
+		end := intmath.Min(len(messageIDs), start+MaxMessageDeleteLimit)
 		err := c.deleteMessages(channelID, messageIDs[start:end], reason)
 		if err != nil {
 			return err

state/state.go

@@ -606,30 +606,30 @@ func (s *State) Messages(channelID discord.ChannelID, limit uint) ([]discord.Mes
 	if len(storeMessages) > 0 && s.tracksMessage(&storeMessages[0]) {
 		// Is the channel tiny?
 		s.fewMutex.Lock()
-		if _, ok := s.fewMessages[channelID]; ok {
-			s.fewMutex.Unlock()
+		_, isTiny := s.fewMessages[channelID]
+		s.fewMutex.Unlock()
+		if isTiny {
 			return storeMessages, nil
 		}
 
 		// No, fetch from the API.
-		s.fewMutex.Unlock()
 	} else {
-		// Something wrong with the cached messages, make sure they aren't
+		// Something's wrong with the cached messages, make sure they aren't
 		// returned.
 		storeMessages = nil
 	}
 
 	// Store already has enough messages.
-	if len(storeMessages) >= int(limit) && limit > 0 {
-		return storeMessages[:limit], nil
-	}
-
-	// Decrease the limit, if we aren't fetching all messages.
 	if limit > 0 {
+		if len(storeMessages) >= int(limit) {
+			return storeMessages[:limit], nil
+		}
+
+		// Decrease the limit, if we aren't fetching all messages.
 		limit -= uint(len(storeMessages))
 	}
 
-	var before discord.MessageID = 0
+	var before discord.MessageID
 	if len(storeMessages) > 0 {
 		before = storeMessages[len(storeMessages)-1].ID
 	}
@@ -639,8 +639,10 @@ func (s *State) Messages(channelID discord.ChannelID, limit uint) ([]discord.Mes
 		return nil, err
 	}
 
-	if len(storeMessages)+len(apiMessages) < s.MaxMessages() {
+	if len(apiMessages) < int(limit) {
 		// Tiny channel, store this.
+		// TODO: this tiny channel check isn't very perfect, but it should
+		// accomplish what we want.
 		s.fewMutex.Lock()
 		s.fewMessages[channelID] = struct{}{}
 		s.fewMutex.Unlock()
@@ -668,16 +670,9 @@ func (s *State) Messages(channelID discord.ChannelID, limit uint) ([]discord.Mes
 		apiMessages[i].GuildID = guildID
 	}
 
-	if s.tracksMessage(&apiMessages[0]) && len(storeMessages) < s.MaxMessages() {
-		// Only add as many messages as the store can hold.
-		i := s.MaxMessages() - len(storeMessages)
-		if i > len(apiMessages) {
-			i = len(apiMessages)
-		}
-
-		msgs := apiMessages[:i]
-		for i := range msgs {
-			s.Cabinet.MessageSet(&msgs[i], false)
+	if s.tracksMessage(&apiMessages[0]) {
+		for i := range apiMessages {
+			s.Cabinet.MessageSet(&apiMessages[i], false)
 		}
 	}