solana_libra_state_view 0.0.0

Solana Libra state_view
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// Copyright (c) The Libra Core Contributors
// SPDX-License-Identifier: Apache-2.0

//! This crate defines [`trait StateView`](StateView).

use failure::prelude::*;
use types::access_path::AccessPath;

/// `StateView` is a trait that defines a read-only snapshot of the global state. It is passed to
/// the VM for transaction execution, during which the VM is guaranteed to read anything at the
/// given state.
pub trait StateView {
    /// Gets the state for a single access path.
    fn get(&self, access_path: &AccessPath) -> Result<Option<Vec<u8>>>;

    /// Gets states for a list of access paths.
    fn multi_get(&self, access_paths: &[AccessPath]) -> Result<Vec<Option<Vec<u8>>>>;

    /// VM needs this method to know whether the current state view is for genesis state creation.
    /// Currently TransactionPayload::WriteSet is only valid for genesis state creation.
    fn is_genesis(&self) -> bool;
}