[MODERATION] user blocking

- Add the ability to block a user via their profile page.
- This will unstar their repositories and visa versa.
- Blocked users cannot create issues or pull requests on your the doer's repositories (mind that this is not the case for organizations).
- Blocked users cannot comment on the doer's opened issues or pull requests.
- Blocked users cannot add reactions to doer's comments.
- Blocked users cannot cause a notification trough mentioning the doer.

Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/540
(cherry picked from commit 687d852480)
(cherry picked from commit 0c32a4fde5)

models/repo/watch.go

@@ -10,6 +10,8 @@ import (
 	user_model "code.gitea.io/gitea/models/user"
 	"code.gitea.io/gitea/modules/setting"
 	"code.gitea.io/gitea/modules/timeutil"
+
+	"xorm.io/builder"
 )
 
 // WatchMode specifies what kind of watch the user has on a repository
@@ -142,6 +144,21 @@ func GetWatchers(ctx context.Context, repoID int64) ([]*Watch, error) {
 		Find(&watches)
 }
 
+// GetWatchersExcludeBlocked returns all watchers of given repository, whereby
+// the doer isn't blocked by one of the watchers.
+func GetWatchersExcludeBlocked(ctx context.Context, repoID, doerID int64) ([]*Watch, error) {
+	watches := make([]*Watch, 0, 10)
+	return watches, db.GetEngine(ctx).
+		Join("INNER", "`user`", "`user`.id = `watch`.user_id").
+		Join("LEFT", "forgejo_blocked_user", "forgejo_blocked_user.user_id = `watch`.user_id").
+		Where("`watch`.repo_id=?", repoID).
+		And("`watch`.mode<>?", WatchModeDont).
+		And("`user`.is_active=?", true).
+		And("`user`.prohibit_login=?", false).
+		And(builder.Or(builder.IsNull{"`forgejo_blocked_user`.block_id"}, builder.Neq{"`forgejo_blocked_user`.block_id": doerID})).
+		Find(&watches)
+}
+
 // GetRepoWatchersIDs returns IDs of watchers for a given repo ID
 // but avoids joining with `user` for performance reasons
 // User permissions must be verified elsewhere if required