| 1 | -- Permanent tombstones for erased people and workspaces (src/erasure.ts), |
| 2 | -- and the channels a purge still has to visit. |
| 3 | CREATE TABLE erased_subjects (id TEXT PRIMARY KEY, kind TEXT NOT NULL); |
| 4 | CREATE TABLE purge_channels (subject_id TEXT NOT NULL, channel_id TEXT NOT NULL, PRIMARY KEY(subject_id, channel_id)); |
| 5 | |
| 6 | -- A purge finds a person's messages, reactions and channels without scanning every row. |
| 7 | CREATE INDEX messages_by_author ON messages (author); |
| 8 | CREATE INDEX reactions_by_principal ON reactions (principal); |
| 9 | CREATE INDEX channels_by_creator ON channels (created_by); |
| 10 | |
| 11 | -- Late, in-flight writes cannot recreate the erased person's membership, |
| 12 | -- messages or reactions. Each looks the tombstone up by its key. |
| 13 | CREATE TRIGGER erased_message BEFORE INSERT ON messages WHEN NEW.author LIKE 'user:%' AND EXISTS ( |
| 14 | SELECT 1 FROM erased_subjects WHERE id = substr(NEW.author, 6) AND kind = 'user' |
| 15 | ) BEGIN SELECT RAISE(IGNORE); END; |
| 16 | CREATE TRIGGER erased_member BEFORE INSERT ON channel_members WHEN NEW.principal LIKE 'user:%' AND EXISTS ( |
| 17 | SELECT 1 FROM erased_subjects WHERE id = substr(NEW.principal, 6) AND kind = 'user' |
| 18 | ) BEGIN SELECT RAISE(IGNORE); END; |
| 19 | CREATE TRIGGER erased_reaction BEFORE INSERT ON reactions WHEN (NEW.principal LIKE 'user:%' AND EXISTS ( |
| 20 | SELECT 1 FROM erased_subjects WHERE id = substr(NEW.principal, 6) AND kind = 'user' |
| 21 | )) OR NOT EXISTS (SELECT 1 FROM messages WHERE id = NEW.message_id) BEGIN SELECT RAISE(IGNORE); END; |
| 22 | |
| 23 | -- Nothing of an erased workspace comes back. |
| 24 | CREATE TRIGGER erased_channel BEFORE INSERT ON channels WHEN EXISTS ( |
| 25 | SELECT 1 FROM erased_subjects WHERE id = NEW.workspace_id AND kind = 'workspace' |
| 26 | ) BEGIN SELECT RAISE(IGNORE); END; |
| 27 | CREATE TRIGGER erased_general_joined BEFORE INSERT ON general_joined WHEN EXISTS ( |
| 28 | SELECT 1 FROM erased_subjects WHERE id = NEW.workspace_id AND kind = 'workspace' |
| 29 | ) BEGIN SELECT RAISE(IGNORE); END; |
| 30 | CREATE TRIGGER erased_custom_emoji BEFORE INSERT ON custom_emoji WHEN EXISTS ( |
| 31 | SELECT 1 FROM erased_subjects WHERE id = NEW.workspace_id AND kind = 'workspace' |
| 32 | ) BEGIN SELECT RAISE(IGNORE); END; |
| 33 | CREATE TRIGGER erased_chat_settings BEFORE INSERT ON chat_settings WHEN EXISTS ( |
| 34 | SELECT 1 FROM erased_subjects WHERE id = NEW.workspace_id AND kind = 'workspace' |
| 35 | ) BEGIN SELECT RAISE(IGNORE); END; |
| 36 | CREATE TRIGGER erased_chat_meter BEFORE INSERT ON chat_meter WHEN EXISTS ( |
| 37 | SELECT 1 FROM erased_subjects WHERE id = NEW.workspace_id AND kind = 'workspace' |
| 38 | ) BEGIN SELECT RAISE(IGNORE); END; |
| 39 | |
| 40 | -- A message or member of a channel that is gone (an erased one) is not kept. |
| 41 | CREATE TRIGGER orphan_message BEFORE INSERT ON messages WHEN NOT EXISTS ( |
| 42 | SELECT 1 FROM channels WHERE id = NEW.channel_id |
| 43 | ) BEGIN SELECT RAISE(IGNORE); END; |
| 44 | CREATE TRIGGER orphan_member BEFORE INSERT ON channel_members WHEN NOT EXISTS ( |
| 45 | SELECT 1 FROM channels WHERE id = NEW.channel_id |
| 46 | ) BEGIN SELECT RAISE(IGNORE); END; |