Add sysvar support (#5838)

sdk/src/sysvar/clock.rs

@@ -1,10 +1,7 @@
 //! This account contains the clock slot, epoch, and stakers_epoch
 //!
-use crate::account::Account;
-use crate::sysvar;
-use bincode::serialized_size;
 
-pub use crate::clock::{Epoch, Slot};
+pub use crate::clock::{Epoch, Segment, Slot};
 
 const ID: [u8; 32] = [
     6, 167, 213, 23, 24, 199, 116, 201, 40, 86, 99, 152, 105, 29, 94, 182, 139, 94, 184, 163, 155,
@@ -21,59 +18,3 @@ pub struct Clock {
     pub epoch: Epoch,
     pub stakers_epoch: Epoch,
 }
-
-impl Clock {
-    pub fn from(account: &Account) -> Option<Self> {
-        account.deserialize_data().ok()
-    }
-    pub fn to(&self, account: &mut Account) -> Option<()> {
-        account.serialize_data(self).ok()
-    }
-
-    pub fn size_of() -> usize {
-        serialized_size(&Self::default()).unwrap() as usize
-    }
-}
-
-pub fn create_account(
-    lamports: u64,
-    slot: Slot,
-    segment: Segment,
-    epoch: Epoch,
-    stakers_epoch: Epoch,
-) -> Account {
-    Account::new_data(
-        lamports,
-        &Clock {
-            slot,
-            segment,
-            epoch,
-            stakers_epoch,
-        },
-        &sysvar::id(),
-    )
-    .unwrap()
-}
-
-use crate::account::KeyedAccount;
-use crate::clock::Segment;
-use crate::instruction::InstructionError;
-
-pub fn from_keyed_account(account: &KeyedAccount) -> Result<Clock, InstructionError> {
-    if !check_id(account.unsigned_key()) {
-        return Err(InstructionError::InvalidArgument);
-    }
-    Clock::from(account.account).ok_or(InstructionError::InvalidArgument)
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn test_create_account() {
-        let account = create_account(1, 0, 0, 0, 0);
-        let clock = Clock::from(&account).unwrap();
-        assert_eq!(clock, Clock::default());
-    }
-}