Move some variables out of model (#17909)

* Move some variables out of model

There were some stuff that's not necessary to be in model
and can just remain unexported variables.

```release-note
NONE
```

* Add license

```release-note
NONE
```

app/command.go

@@ -10,6 +10,7 @@ import (
 	"io/ioutil"
 	"net/http"
 	"net/url"
+	"regexp"
 	"strings"
 	"sync"
 	"unicode"
@@ -23,8 +24,11 @@ import (
 
 const (
 	CmdCustomStatusTrigger = "status"
+	usernameSpecialChars   = ".-_"
 )
 
+var atMentionRegexp = regexp.MustCompile(`\B@[[:alnum:]][[:alnum:]\.\-_:]*`)
+
 type CommandProvider interface {
 	GetTrigger() string
 	GetCommand(a *App, T i18n.TranslateFunc) *model.Command
@@ -233,7 +237,7 @@ func (a *App) MentionsToTeamMembers(message, teamID string) model.UserMentionMap
 		Id   string
 	}
 
-	possibleMentions := model.PossibleAtMentions(message)
+	possibleMentions := possibleAtMentions(message)
 	mentionChan := make(chan *mentionMapItem, len(possibleMentions))
 
 	var wg sync.WaitGroup
@@ -252,8 +256,8 @@ func (a *App) MentionsToTeamMembers(message, teamID string) model.UserMentionMap
 			// If it's a http.StatusNotFound error, check for usernames in substrings
 			// without trailing punctuation
 			if nErr != nil {
-				trimmed, ok := model.TrimUsernameSpecialChar(mention)
-				for ; ok; trimmed, ok = model.TrimUsernameSpecialChar(trimmed) {
+				trimmed, ok := trimUsernameSpecialChar(mention)
+				for ; ok; trimmed, ok = trimUsernameSpecialChar(trimmed) {
 					userFromTrimmed, nErr := a.Srv().Store.User().GetByUsername(trimmed)
 					if nErr != nil && !errors.As(nErr, &nfErr) {
 						return
@@ -770,3 +774,37 @@ func (a *App) DeleteCommand(commandID string) *model.AppError {
 
 	return nil
 }
+
+// possibleAtMentions returns all substrings in message that look like valid @
+// mentions.
+func possibleAtMentions(message string) []string {
+	var names []string
+
+	if !strings.Contains(message, "@") {
+		return names
+	}
+
+	alreadyMentioned := make(map[string]bool)
+	for _, match := range atMentionRegexp.FindAllString(message, -1) {
+		name := model.NormalizeUsername(match[1:])
+		if !alreadyMentioned[name] && model.IsValidUsernameAllowRemote(name) {
+			names = append(names, name)
+			alreadyMentioned[name] = true
+		}
+	}
+
+	return names
+}
+
+// trimUsernameSpecialChar tries to remove the last character from word if it
+// is a special character for usernames (dot, dash or underscore). If not, it
+// returns the same string.
+func trimUsernameSpecialChar(word string) (string, bool) {
+	len := len(word)
+
+	if len > 0 && strings.LastIndexAny(word, usernameSpecialChars) == (len-1) {
+		return word[:len-1], true
+	}
+
+	return word, false
+}

app/command_test.go

@@ -1,7 +1,7 @@
 // Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
 // See LICENSE.txt for license information.
 
-package model
+package app
 
 import (
 	"testing"
@@ -49,7 +49,7 @@ func TestPossibleAtMentions(t *testing.T) {
 	}
 
 	for _, data := range fixture {
-		actual := PossibleAtMentions(data.message)
+		actual := possibleAtMentions(data.message)
 		require.ElementsMatch(t, actual, data.expected)
 	}
 }
@@ -73,7 +73,7 @@ func TestTrimUsernameSpecialChar(t *testing.T) {
 	}
 
 	for _, data := range fixture {
-		actualString, actualBool := TrimUsernameSpecialChar(data.word)
+		actualString, actualBool := trimUsernameSpecialChar(data.word)
 		require.Equal(t, actualBool, data.expectedBool)
 		if actualBool {
 			require.Equal(t, actualString, data.expectedString)

app/post.go

@@ -9,6 +9,7 @@ import (
 	"errors"
 	"fmt"
 	"net/http"
+	"regexp"
 	"strings"
 	"sync"
 	"time"
@@ -29,6 +30,8 @@ const (
 	PageDefault             = 0
 )
 
+var atMentionPattern = regexp.MustCompile(`\B@`)
+
 func (a *App) CreatePostAsUser(c *request.Context, post *model.Post, currentSessionId string, setOnline bool) (*model.Post, *model.AppError) {
 	// Check that channel has not been deleted
 	channel, errCh := a.Srv().Store.Channel().Get(post.ChannelId, true)
@@ -442,7 +445,7 @@ func (a *App) FillInPostProps(post *model.Post, channel *model.Channel) *model.A
 		post.DelProp("channel_mentions")
 	}
 
-	matched := model.AtMentionPattern.MatchString(post.Message)
+	matched := atMentionPattern.MatchString(post.Message)
 	if a.Srv().License() != nil && *a.Srv().License().Features.LDAPGroups && matched && !a.HasPermissionToChannel(post.UserId, post.ChannelId, model.PermissionUseGroupMentions) {
 		post.AddProp(model.PostPropsGroupHighlightDisabled, true)
 	}

model/at_mentions.go

@@ -1,47 +0,0 @@
-// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
-// See LICENSE.txt for license information.
-
-package model
-
-import (
-	"regexp"
-	"strings"
-)
-
-var atMentionRegexp = regexp.MustCompile(`\B@[[:alnum:]][[:alnum:]\.\-_:]*`)
-
-const usernameSpecialChars = ".-_"
-
-// PossibleAtMentions returns all substrings in message that look like valid @
-// mentions.
-func PossibleAtMentions(message string) []string {
-	var names []string
-
-	if !strings.Contains(message, "@") {
-		return names
-	}
-
-	alreadyMentioned := make(map[string]bool)
-	for _, match := range atMentionRegexp.FindAllString(message, -1) {
-		name := NormalizeUsername(match[1:])
-		if !alreadyMentioned[name] && IsValidUsernameAllowRemote(name) {
-			names = append(names, name)
-			alreadyMentioned[name] = true
-		}
-	}
-
-	return names
-}
-
-// TrimUsernameSpecialChar tries to remove the last character from word if it
-// is a special character for usernames (dot, dash or underscore). If not, it
-// returns the same string.
-func TrimUsernameSpecialChar(word string) (string, bool) {
-	len := len(word)
-
-	if len > 0 && strings.LastIndexAny(word, usernameSpecialChars) == (len-1) {
-		return word[:len-1], true
-	}
-
-	return word, false
-}

model/emoji.go

@@ -18,8 +18,6 @@ const (
 
 var EmojiPattern = regexp.MustCompile(`:[a-zA-Z0-9_+-]+:`)
 
-var ReverseSystemEmojisMap = makeReverseEmojiMap()
-
 type Emoji struct {
 	Id        string `json:"id"`
 	CreateAt  int64  `json:"create_at"`
@@ -51,8 +49,10 @@ func makeReverseEmojiMap() map[string][]string {
 	return reverseEmojiMap
 }
 
+var reverseSystemEmojisMap = makeReverseEmojiMap()
+
 func GetEmojiNameFromUnicode(unicode string) (emojiName string, count int) {
-	if emojiNames, found := ReverseSystemEmojisMap[unicode]; found {
+	if emojiNames, found := reverseSystemEmojisMap[unicode]; found {
 		return emojiNames[0], len(emojiNames)
 	}
 

model/post.go

@@ -69,8 +69,6 @@ const (
 	PostPropsGroupHighlightDisabled   = "disable_group_highlight"
 )
 
-var AtMentionPattern = regexp.MustCompile(`\B@`)
-
 type Post struct {
 	Id         string `json:"id"`
 	CreateAt   int64  `json:"create_at"`