1 files changed, 242 insertions, 0 deletions

diff --git a/models/issues/content_history.go b/models/issues/content_history.go
new file mode 100644
index 0000000..cd3e217
--- /dev/null
+++ b/models/issues/content_history.go
@@ -0,0 +1,242 @@
+// Copyright 2021 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package issues
+
+import (
+	"context"
+	"fmt"
+
+	"code.gitea.io/gitea/models/avatars"
+	"code.gitea.io/gitea/models/db"
+	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/timeutil"
+	"code.gitea.io/gitea/modules/util"
+
+	"xorm.io/builder"
+)
+
+// ContentHistory save issue/comment content history revisions.
+type ContentHistory struct {
+	ID             int64 `xorm:"pk autoincr"`
+	PosterID       int64
+	IssueID        int64              `xorm:"INDEX"`
+	CommentID      int64              `xorm:"INDEX"`
+	EditedUnix     timeutil.TimeStamp `xorm:"INDEX"`
+	ContentText    string             `xorm:"LONGTEXT"`
+	IsFirstCreated bool
+	IsDeleted      bool
+}
+
+// TableName provides the real table name
+func (m *ContentHistory) TableName() string {
+	return "issue_content_history"
+}
+
+func init() {
+	db.RegisterModel(new(ContentHistory))
+}
+
+// SaveIssueContentHistory save history
+func SaveIssueContentHistory(ctx context.Context, posterID, issueID, commentID int64, editTime timeutil.TimeStamp, contentText string, isFirstCreated bool) error {
+	ch := &ContentHistory{
+		PosterID:       posterID,
+		IssueID:        issueID,
+		CommentID:      commentID,
+		ContentText:    contentText,
+		EditedUnix:     editTime,
+		IsFirstCreated: isFirstCreated,
+	}
+	if err := db.Insert(ctx, ch); err != nil {
+		log.Error("can not save issue content history. err=%v", err)
+		return err
+	}
+	// We only keep at most 20 history revisions now. It is enough in most cases.
+	// If there is a special requirement to keep more, we can consider introducing a new setting option then, but not now.
+	KeepLimitedContentHistory(ctx, issueID, commentID, 20)
+	return nil
+}
+
+// KeepLimitedContentHistory keeps at most `limit` history revisions, it will hard delete out-dated revisions, sorting by revision interval
+// we can ignore all errors in this function, so we just log them
+func KeepLimitedContentHistory(ctx context.Context, issueID, commentID int64, limit int) {
+	type IDEditTime struct {
+		ID         int64
+		EditedUnix timeutil.TimeStamp
+	}
+
+	var res []*IDEditTime
+	err := db.GetEngine(ctx).Select("id, edited_unix").Table("issue_content_history").
+		Where(builder.Eq{"issue_id": issueID, "comment_id": commentID}).
+		OrderBy("edited_unix ASC").
+		Find(&res)
+	if err != nil {
+		log.Error("can not query content history for deletion, err=%v", err)
+		return
+	}
+	if len(res) <= 2 {
+		return
+	}
+
+	outDatedCount := len(res) - limit
+	for outDatedCount > 0 {
+		var indexToDelete int
+		minEditedInterval := -1
+		// find a history revision with minimal edited interval to delete, the first and the last should never be deleted
+		for i := 1; i < len(res)-1; i++ {
+			editedInterval := int(res[i].EditedUnix - res[i-1].EditedUnix)
+			if minEditedInterval == -1 || editedInterval < minEditedInterval {
+				minEditedInterval = editedInterval
+				indexToDelete = i
+			}
+		}
+		if indexToDelete == 0 {
+			break
+		}
+
+		// hard delete the found one
+		_, err = db.GetEngine(ctx).Delete(&ContentHistory{ID: res[indexToDelete].ID})
+		if err != nil {
+			log.Error("can not delete out-dated content history, err=%v", err)
+			break
+		}
+		res = append(res[:indexToDelete], res[indexToDelete+1:]...)
+		outDatedCount--
+	}
+}
+
+// QueryIssueContentHistoryEditedCountMap query related history count of each comment (comment_id = 0 means the main issue)
+// only return the count map for "edited" (history revision count > 1) issues or comments.
+func QueryIssueContentHistoryEditedCountMap(dbCtx context.Context, issueID int64) (map[int64]int, error) {
+	type HistoryCountRecord struct {
+		CommentID    int64
+		HistoryCount int
+	}
+	records := make([]*HistoryCountRecord, 0)
+
+	err := db.GetEngine(dbCtx).Select("comment_id, COUNT(1) as history_count").
+		Table("issue_content_history").
+		Where(builder.Eq{"issue_id": issueID}).
+		GroupBy("comment_id").
+		Having("count(1) > 1").
+		Find(&records)
+	if err != nil {
+		log.Error("can not query issue content history count map. err=%v", err)
+		return nil, err
+	}
+
+	res := map[int64]int{}
+	for _, r := range records {
+		res[r.CommentID] = r.HistoryCount
+	}
+	return res, nil
+}
+
+// IssueContentListItem the list for web ui
+type IssueContentListItem struct {
+	UserID         int64
+	UserName       string
+	UserFullName   string
+	UserAvatarLink string
+
+	HistoryID      int64
+	EditedUnix     timeutil.TimeStamp
+	IsFirstCreated bool
+	IsDeleted      bool
+}
+
+// FetchIssueContentHistoryList fetch list
+func FetchIssueContentHistoryList(dbCtx context.Context, issueID, commentID int64) ([]*IssueContentListItem, error) {
+	res := make([]*IssueContentListItem, 0)
+	err := db.GetEngine(dbCtx).Select("u.id as user_id, u.name as user_name, u.full_name as user_full_name,"+
+		"h.id as history_id, h.edited_unix, h.is_first_created, h.is_deleted").
+		Table([]string{"issue_content_history", "h"}).
+		Join("LEFT", []string{"user", "u"}, "h.poster_id = u.id").
+		Where(builder.Eq{"issue_id": issueID, "comment_id": commentID}).
+		OrderBy("edited_unix DESC").
+		Find(&res)
+	if err != nil {
+		log.Error("can not fetch issue content history list. err=%v", err)
+		return nil, err
+	}
+
+	for _, item := range res {
+		if item.UserID > 0 {
+			item.UserAvatarLink = avatars.GenerateUserAvatarFastLink(item.UserName, 0)
+		} else {
+			item.UserAvatarLink = avatars.DefaultAvatarLink()
+		}
+	}
+	return res, nil
+}
+
+// HasIssueContentHistory check if a ContentHistory entry exists
+func HasIssueContentHistory(dbCtx context.Context, issueID, commentID int64) (bool, error) {
+	return db.GetEngine(dbCtx).Where("issue_id = ? AND comment_id = ?", issueID, commentID).Exist(new(ContentHistory))
+}
+
+// SoftDeleteIssueContentHistory soft delete
+func SoftDeleteIssueContentHistory(dbCtx context.Context, historyID int64) error {
+	if _, err := db.GetEngine(dbCtx).ID(historyID).Cols("is_deleted", "content_text").Update(&ContentHistory{
+		IsDeleted:   true,
+		ContentText: "",
+	}); err != nil {
+		log.Error("failed to soft delete issue content history. err=%v", err)
+		return err
+	}
+	return nil
+}
+
+// ErrIssueContentHistoryNotExist not exist error
+type ErrIssueContentHistoryNotExist struct {
+	ID int64
+}
+
+// Error error string
+func (err ErrIssueContentHistoryNotExist) Error() string {
+	return fmt.Sprintf("issue content history does not exist [id: %d]", err.ID)
+}
+
+func (err ErrIssueContentHistoryNotExist) Unwrap() error {
+	return util.ErrNotExist
+}
+
+// GetIssueContentHistoryByID get issue content history
+func GetIssueContentHistoryByID(dbCtx context.Context, id int64) (*ContentHistory, error) {
+	h := &ContentHistory{}
+	has, err := db.GetEngine(dbCtx).ID(id).Get(h)
+	if err != nil {
+		return nil, err
+	} else if !has {
+		return nil, ErrIssueContentHistoryNotExist{id}
+	}
+	return h, nil
+}
+
+// GetIssueContentHistoryAndPrev get a history and the previous non-deleted history (to compare)
+func GetIssueContentHistoryAndPrev(dbCtx context.Context, issueID, id int64) (history, prevHistory *ContentHistory, err error) {
+	history = &ContentHistory{}
+	has, err := db.GetEngine(dbCtx).Where("id=? AND issue_id=?", id, issueID).Get(history)
+	if err != nil {
+		log.Error("failed to get issue content history %v. err=%v", id, err)
+		return nil, nil, err
+	} else if !has {
+		log.Error("issue content history does not exist. id=%v. err=%v", id, err)
+		return nil, nil, &ErrIssueContentHistoryNotExist{id}
+	}
+
+	prevHistory = &ContentHistory{}
+	has, err = db.GetEngine(dbCtx).Where(builder.Eq{"issue_id": history.IssueID, "comment_id": history.CommentID, "is_deleted": false}).
+		And(builder.Lt{"edited_unix": history.EditedUnix}).
+		OrderBy("edited_unix DESC").Limit(1).
+		Get(prevHistory)
+
+	if err != nil {
+		log.Error("failed to get issue content history %v. err=%v", id, err)
+		return nil, nil, err
+	} else if !has {
+		return history, nil, nil
+	}
+
+	return history, prevHistory, nil
+}