85 lines
2.9 KiB
Rust
85 lines
2.9 KiB
Rust
//! The most recent hashes of a slot's parent banks.
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//!
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//! The _slot hashes sysvar_ provides access to the [`SlotHashes`] type.
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//!
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//! The [`Sysvar::from_account_info`] and [`Sysvar::get`] methods always return
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//! [`ProgramError::UnsupportedSysvar`] because this sysvar account is too large
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//! to process on-chain. Thus this sysvar cannot be accessed on chain, though
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//! one can still use the [`SysvarId::id`], [`SysvarId::check_id`] and
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//! [`Sysvar::size_of`] methods in an on-chain program, and it can be accessed
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//! off-chain through RPC.
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//!
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//! [`SysvarId::id`]: crate::sysvar::SysvarId::id
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//! [`SysvarId::check_id`]: crate::sysvar::SysvarId::check_id
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//!
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//! # Examples
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//!
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//! Calling via the RPC client:
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//!
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//! ```
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//! # use solana_program::example_mocks::solana_sdk;
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//! # use solana_program::example_mocks::solana_rpc_client;
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//! # use solana_sdk::account::Account;
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//! # use solana_rpc_client::rpc_client::RpcClient;
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//! # use solana_sdk::sysvar::slot_hashes::{self, SlotHashes};
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//! # use anyhow::Result;
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//! #
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//! fn print_sysvar_slot_hashes(client: &RpcClient) -> Result<()> {
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//! # client.set_get_account_response(slot_hashes::ID, Account {
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//! # lamports: 1009200,
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//! # data: vec![1, 0, 0, 0, 0, 0, 0, 0, 86, 190, 235, 7, 0, 0, 0, 0, 133, 242, 94, 158, 223, 253, 207, 184, 227, 194, 235, 27, 176, 98, 73, 3, 175, 201, 224, 111, 21, 65, 73, 27, 137, 73, 229, 19, 255, 192, 193, 126],
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//! # owner: solana_sdk::system_program::ID,
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//! # executable: false,
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//! # rent_epoch: 307,
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//! # });
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//! #
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//! let slot_hashes = client.get_account(&slot_hashes::ID)?;
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//! let data: SlotHashes = bincode::deserialize(&slot_hashes.data)?;
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//!
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//! Ok(())
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//! }
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//! #
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//! # let client = RpcClient::new(String::new());
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//! # print_sysvar_slot_hashes(&client)?;
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//! #
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//! # Ok::<(), anyhow::Error>(())
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//! ```
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pub use crate::slot_hashes::SlotHashes;
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use crate::{account_info::AccountInfo, program_error::ProgramError, sysvar::Sysvar};
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crate::declare_sysvar_id!("SysvarS1otHashes111111111111111111111111111", SlotHashes);
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impl Sysvar for SlotHashes {
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// override
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fn size_of() -> usize {
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// hard-coded so that we don't have to construct an empty
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20_488 // golden, update if MAX_ENTRIES changes
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}
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fn from_account_info(_account_info: &AccountInfo) -> Result<Self, ProgramError> {
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// This sysvar is too large to bincode::deserialize in-program
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Err(ProgramError::UnsupportedSysvar)
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}
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}
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#[cfg(test)]
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mod tests {
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use {
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super::*,
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crate::{clock::Slot, hash::Hash, slot_hashes::MAX_ENTRIES},
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};
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#[test]
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fn test_size_of() {
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assert_eq!(
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SlotHashes::size_of(),
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bincode::serialized_size(
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&(0..MAX_ENTRIES)
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.map(|slot| (slot as Slot, Hash::default()))
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.collect::<SlotHashes>()
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)
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.unwrap() as usize
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);
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}
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}
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