We need to serialize ops to get account history plugin to work with the new DB architecture:
- There's no way to propagate a custom allocator through static_variant
- Thus, static_variant is unusable from the database if any member types have fields that require dynamic memory allocation
- As a consequence, we can no longer store operation in any database object
The "fix" is to serialize history objects.
该提问来源于开源项目：steemit/steem
分享 A fair amount of refactoring is needed to support this change.
Cleanup of where things are located: - Move history objects to account_history_plugin - Move impacted.hpp from app to account_history_plugin - Update other plugins that reference impacted.hpp to require account_history_plugin at build time
Cleanup of notification API:
- Some plugins care about deserialized ops
- Therefore, object passed to pre/post apply hooks should be deserialized
- account_history_plugin serializes objects
- Therefore we need a new non-database type for storing unserialized operations. Call this type operation_notification
Since we're breaking the hook API anyway, I'll also modify it to have operation_notification be passed into both pre- and post-apply, instead of the current behavior (which is returning from pre-apply). This should avoid some unnecessary copying. For further savings, since it's no longer a DB object we can store a reference to the operation in the object.
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