#### Problem
Both AppendVec::cloned_account() and ReadableAccount::to_account_shard_data()
returns an AccountSharedData instance by cloning itself as pointed out under
a comment in PR #32380.
#### Summary of Changes
This PR removes AccountsFile::cloned_account() and replaces its call-sites by
ReadableAccount::to_account_shared_data().
#### Problem
AppendVec currently uses std::io::ErrorKind::Other for its own errors.
#### Summary of Changes
This PR introduces AppendVecError and has AppendVec use it.
#### Problem
AccountsFile- and AppendVec-related code uses io::Error for their main error type. However, there're many errors under AccountsFile that don't belong to io::Error.
#### Summary of Changes
This PR introduces AccountsFileError and makes minimum changes to keep the PR small.
Subsequent changes related to this will be in separate PRs.
#### Problem
As we start supporting new storage formats, alignment-related constants and macros
defined in append_vec.rs aren't only specific to AppendVec.
#### Summary of Changes
Move alignment-related constants/macros from append_vec.rs to accounts_file.rs
#### Problem
The existing StoredAccountMeta requires the file and in-memory layout of
account metadata to match StoredMeta and AccountMeta. This limits the
flexibility to implement different accounts storage file formats.
#### Summary of Changes
This PR abstracts out StoredAccountMeta as an Enum.
#### Problem
The existing append_accounts returns a vector of offsets, which accounts-db
later uses it to infer the storage size of each account. However, such inference
does not apply to the new hot/cold storage format.
#### Summary of Changes
This PR changes the return value of append_accounts() to `Vec<StoredAccountInfo>`,
which includes both offset and storage size information of an account.
This PR makes all the StoredAccountMeta fields pub(crate)
and provides getter functions to access its member fields.
This PR is a preparation step for abstracting out StoredAccountMeta.
#### Problem
As we start supporting new storage formats, those account-meta
structs will be shared by different storage formats and thus need
a new home.
#### Summary of Changes
This PR creates meta.rs under account_storage and moves all the account-meta
structs out from append_vec.rs.
adds unit test asserting the type layout of structures in append_vec
---------
Co-authored-by: Richard Patel <ripatel@jumptrading.com>
Co-authored-by: brooks <brooks@solana.com>
Alexander Meißner
Yueh-Hsuan Chiang
Brooks
Jeff Washington (jwash)
Pankaj Garg
Richard Patel
Richard Patel
behzad nouri
Xiang Zhu
apfitzge
HaoranYi
Jeff Washington (jwash)
Michael Vines
Anton Lazarev