Move IssueUser code to separate file (#836)

Also add unit tests

models/issue_user.go

@@ -0,0 +1,113 @@
+// Copyright 2017 The Gogs Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package models
+
+import (
+	"fmt"
+)
+
+// IssueUser represents an issue-user relation.
+type IssueUser struct {
+	ID          int64 `xorm:"pk autoincr"`
+	UID         int64 `xorm:"INDEX"` // User ID.
+	IssueID     int64
+	IsRead      bool
+	IsAssigned  bool
+	IsMentioned bool
+}
+
+func newIssueUsers(e Engine, repo *Repository, issue *Issue) error {
+	assignees, err := repo.getAssignees(e)
+	if err != nil {
+		return fmt.Errorf("getAssignees: %v", err)
+	}
+
+	// Poster can be anyone, append later if not one of assignees.
+	isPosterAssignee := false
+
+	// Leave a seat for poster itself to append later, but if poster is one of assignee
+	// and just waste 1 unit is cheaper than re-allocate memory once.
+	issueUsers := make([]*IssueUser, 0, len(assignees)+1)
+	for _, assignee := range assignees {
+		issueUsers = append(issueUsers, &IssueUser{
+			IssueID:    issue.ID,
+			UID:        assignee.ID,
+			IsAssigned: assignee.ID == issue.AssigneeID,
+		})
+		isPosterAssignee = isPosterAssignee || assignee.ID == issue.PosterID
+	}
+	if !isPosterAssignee {
+		issueUsers = append(issueUsers, &IssueUser{
+			IssueID: issue.ID,
+			UID:     issue.PosterID,
+		})
+	}
+
+	if _, err = e.Insert(issueUsers); err != nil {
+		return err
+	}
+	return nil
+}
+
+func updateIssueUserByAssignee(e Engine, issue *Issue) (err error) {
+	if _, err = e.Exec("UPDATE `issue_user` SET is_assigned = ? WHERE issue_id = ?", false, issue.ID); err != nil {
+		return err
+	}
+
+	// Assignee ID equals to 0 means clear assignee.
+	if issue.AssigneeID > 0 {
+		if _, err = e.Exec("UPDATE `issue_user` SET is_assigned = ? WHERE uid = ? AND issue_id = ?", true, issue.AssigneeID, issue.ID); err != nil {
+			return err
+		}
+	}
+
+	return updateIssue(e, issue)
+}
+
+// UpdateIssueUserByAssignee updates issue-user relation for assignee.
+func UpdateIssueUserByAssignee(issue *Issue) (err error) {
+	sess := x.NewSession()
+	defer sessionRelease(sess)
+	if err = sess.Begin(); err != nil {
+		return err
+	}
+
+	if err = updateIssueUserByAssignee(sess, issue); err != nil {
+		return err
+	}
+
+	return sess.Commit()
+}
+
+// UpdateIssueUserByRead updates issue-user relation for reading.
+func UpdateIssueUserByRead(uid, issueID int64) error {
+	_, err := x.Exec("UPDATE `issue_user` SET is_read=? WHERE uid=? AND issue_id=?", true, uid, issueID)
+	return err
+}
+
+// UpdateIssueUsersByMentions updates issue-user pairs by mentioning.
+func UpdateIssueUsersByMentions(e Engine, issueID int64, uids []int64) error {
+	for _, uid := range uids {
+		iu := &IssueUser{
+			UID:     uid,
+			IssueID: issueID,
+		}
+		has, err := e.Get(iu)
+		if err != nil {
+			return err
+		}
+
+		iu.IsMentioned = true
+		if has {
+			_, err = e.Id(iu.ID).AllCols().Update(iu)
+		} else {
+			_, err = e.Insert(iu)
+		}
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}