API to read account meta data from storage

Author: pgarg66

runtime/src/accounts_db.rs

@@ -18,6 +18,7 @@
 //! tracks the number of commits to the entire data store. So the latest
 //! commit for each slot entry would be indexed.
 
+use crate::append_vec::AccountMeta;
 use {
     crate::{
         account_info::{AccountInfo, Offset, StorageLocation, StoredSize},
@@ -809,6 +810,29 @@ impl<'a> LoadedAccountAccessor<'a> {
             }
         }
     }
+
+    fn get_account_meta(&self) -> Option<AccountMeta> {
+        match self {
+            LoadedAccountAccessor::Cached(cached_account) => {
+                cached_account.as_ref().map(|cached_account| AccountMeta {
+                    lamports: cached_account.account.lamports(),
+                    rent_epoch: cached_account.account.rent_epoch(),
+                    owner: cached_account.account.owner().clone(),
+                    executable: cached_account.account.executable(),
+                })
+            }
+            LoadedAccountAccessor::Stored(maybe_storage_entry) => {
+                // storage entry may not be present if slot was cleaned up in
+                // between reading the accounts index and calling this function to
+                // get account meta from the storage entry here
+                maybe_storage_entry
+                    .as_ref()
+                    .and_then(|(storage_entry, offset)| {
+                        storage_entry.accounts.get_account_meta(*offset)
+                    })
+            }
+        }
+    }
 }
 
 pub enum LoadedAccount<'a> {
@@ -4913,6 +4937,33 @@ impl AccountsDb {
         self.do_load(ancestors, pubkey, None, load_hint, LoadZeroLamports::None)
     }
 
+    pub fn get_account_meta(&self, ancestors: &Ancestors, pubkey: &Pubkey) -> Option<AccountMeta> {
+        let (slot, storage_location, _maybe_account_accesor) =
+            self.read_index_for_accessor_or_load_slow(ancestors, pubkey, None, false)?;
+
+        if !storage_location.is_cached() {
+            let result = self.read_only_accounts_cache.load(*pubkey, slot);
+            if let Some(account) = result {
+                return Some(AccountMeta {
+                    lamports: account.lamports(),
+                    rent_epoch: account.rent_epoch(),
+                    owner: account.owner().clone(),
+                    executable: account.executable(),
+                });
+            }
+        }
+
+        let (account_accessor, _slot) = self.retry_to_get_account_accessor(
+            slot,
+            storage_location,
+            ancestors,
+            pubkey,
+            None,
+            LoadHint::Unspecified,
+        )?;
+        account_accessor.get_account_meta()
+    }
+
     pub fn load_account_into_read_cache(&self, ancestors: &Ancestors, pubkey: &Pubkey) {
         self.do_load_with_populate_read_cache(
             ancestors,
@@ -14082,6 +14133,71 @@ pub mod tests {
         assert_eq!(db.read_only_accounts_cache.cache_len(), 1);
     }
 
+    #[test]
+    fn test_get_account_meta() {
+        let db = Arc::new(AccountsDb::new_with_config_for_tests(
+            Vec::new(),
+            &ClusterType::Development,
+            AccountSecondaryIndexes::default(),
+            AccountShrinkThreshold::default(),
+        ));
+
+        let account1_key = Pubkey::new_unique();
+        let owner1_key = Pubkey::new_unique();
+        let account1 = AccountSharedData::new(321, 10, &owner1_key);
+
+        let account2_key = Pubkey::new_unique();
+        let owner2_key = Pubkey::new_unique();
+        let account2 = AccountSharedData::new(1, 1, &owner2_key);
+
+        db.store_cached((0, &[(&account1_key, &account1)][..]), None);
+        db.store_cached((1, &[(&account2_key, &account2)][..]), None);
+
+        db.add_root(0);
+        db.add_root(1);
+
+        // Flush the cache so that the account meta will be read from the storage
+        db.flush_accounts_cache(true, None);
+        db.clean_accounts_for_tests();
+
+        let account_meta = db
+            .get_account_meta(&Ancestors::default(), &account1_key)
+            .unwrap();
+        assert_eq!(account_meta.lamports, 321);
+        assert_eq!(account_meta.owner, owner1_key);
+
+        let account_meta = db
+            .get_account_meta(&Ancestors::default(), &account2_key)
+            .unwrap();
+        assert_eq!(account_meta.lamports, 1);
+        assert_eq!(account_meta.owner, owner2_key);
+
+        // Flush the cache and load account1 (so that it's in the cache)
+        db.flush_accounts_cache(true, None);
+        db.clean_accounts_for_tests();
+        let _ = db
+            .do_load(
+                &Ancestors::default(),
+                &account1_key,
+                Some(0),
+                LoadHint::Unspecified,
+                LoadZeroLamports::SomeWithZeroLamportAccountForTests,
+            )
+            .unwrap();
+
+        let account_meta = db
+            .get_account_meta(&Ancestors::default(), &account1_key)
+            .unwrap();
+        assert_eq!(account_meta.lamports, 321);
+        assert_eq!(account_meta.owner, owner1_key);
+
+        let account_meta = db
+            .get_account_meta(&Ancestors::default(), &account2_key)
+            .unwrap();
+        assert_eq!(account_meta.lamports, 1);
+        assert_eq!(account_meta.owner, owner2_key);
+    }
+
     /// a test that will accept either answer
     const LOAD_ZERO_LAMPORTS_ANY_TESTS: LoadZeroLamports = LoadZeroLamports::None;
 

runtime/src/append_vec.rs

@@ -572,7 +572,7 @@ impl AppendVec {
         Some((unsafe { &*ptr }, next))
     }
 
-    /// Return account metadata for the account at `offset` if its data doesn't overrun
+    /// Return stored account metadata for the account at `offset` if its data doesn't overrun
     /// the internal buffer. Otherwise return None. Also return the offset of the first byte
     /// after the requested data that falls on a 64-byte boundary.
     pub fn get_account<'a>(&'a self, offset: usize) -> Option<(StoredAccountMeta<'a>, usize)> {
@@ -594,6 +594,17 @@ impl AppendVec {
         ))
     }
 
+    /// Return account metadata for the account at `offset` if its data doesn't overrun
+    /// the internal buffer. Otherwise return None.
+    pub fn get_account_meta(&self, offset: usize) -> Option<AccountMeta> {
+        // Skip over StoredMeta data in the account
+        let offset = offset.checked_add(mem::size_of::<StoredMeta>())?;
+        // u64_align! does an unchecked add for alignment. Check that it won't cause an overflow.
+        offset.checked_add(ALIGN_BOUNDARY_OFFSET - 1)?;
+        let (account_meta, _): (&AccountMeta, _) = self.get_type(u64_align!(offset))?;
+        Some(account_meta.clone())
+    }
+
     #[cfg(test)]
     pub fn get_account_test(&self, offset: usize) -> Option<(StoredMeta, AccountSharedData)> {
         let (stored_account, _) = self.get_account(offset)?;
@@ -1047,6 +1058,56 @@ pub mod tests {
         assert_eq!(av.get_account_test(index1).unwrap(), account1);
     }
 
+    #[test]
+    fn test_get_account_meta() {
+        let path = get_append_vec_path("test_append_data");
+        let av = AppendVec::new(&path.path, true, 1024 * 1024);
+        let mut account = create_test_account(5);
+
+        let test_account_meta = AccountMeta {
+            lamports: 12345678,
+            rent_epoch: 123,
+            owner: Pubkey::new_unique(),
+            executable: true,
+        };
+        account.1.set_lamports(test_account_meta.lamports);
+        account.1.set_rent_epoch(test_account_meta.rent_epoch);
+        account.1.set_owner(test_account_meta.owner);
+        account.1.set_executable(test_account_meta.executable);
+
+        let index = av.append_account_test(&account).unwrap();
+        assert_eq!(av.get_account_meta(index), Some(test_account_meta.clone()));
+
+        let mut account1 = create_test_account(6);
+        let test_account_meta1 = AccountMeta {
+            lamports: 87654321,
+            rent_epoch: 234,
+            owner: Pubkey::new_unique(),
+            executable: false,
+        };
+        account1.1.set_lamports(test_account_meta1.lamports);
+        account1.1.set_rent_epoch(test_account_meta1.rent_epoch);
+        account1.1.set_owner(test_account_meta1.owner);
+        account1.1.set_executable(test_account_meta1.executable);
+
+        let index1 = av.append_account_test(&account1).unwrap();
+        assert_eq!(av.get_account_meta(index1), Some(test_account_meta1));
+        assert_eq!(av.get_account_meta(index), Some(test_account_meta));
+
+        // tests for overflow
+        assert_eq!(
+            av.get_account_meta(usize::MAX - mem::size_of::<StoredMeta>()),
+            None
+        );
+
+        assert_eq!(
+            av.get_account_meta(
+                usize::MAX - mem::size_of::<StoredMeta>() - mem::size_of::<AccountMeta>() + 1
+            ),
+            None
+        );
+    }
+
     #[test]
     fn test_append_vec_append_many() {
         let path = get_append_vec_path("test_append_many");