Content hashing

Entity hashing is done in content_hash#getEntityHashes.

• It works by looking at the entity_changes table and going through each of the entity names/types:
  • blobs
  • attributes
  • revisions
  • attachments
  • notes
  • branches
  • etapi_tokens
  • options
• For some reason note_reordering entities are ignored specifically.
• All the rows in entity_changes are then ordered alphabetically, based on their entityId.
• Every entity row is then grouped by entityName and then by sector. The sector is defined as the first character of the id.
• The hash is altered to add the isErased value as well since the hash of deleted entries is not updated.
• For each sector, the hash is calculated using utils.hash, using SHA1 encoded as Base64.