Refactor: move sysvar cache to new module (#22586)

sdk/src/lib.rs

@@ -48,6 +48,8 @@ pub mod shred_version;
 pub mod signature;
 pub mod signer;
 pub mod system_transaction;
+#[doc(hidden)]
+pub mod sysvar_cache;
 pub mod timing;
 pub mod transaction;
 pub mod transport;

sdk/src/process_instruction.rs

@@ -1,4 +1,5 @@
 use {
+    crate::sysvar_cache::SysvarCache,
     itertools::Itertools,
     solana_sdk::{
         account::AccountSharedData,
@@ -8,7 +9,7 @@ use {
         pubkey::Pubkey,
         sysvar::Sysvar,
     },
-    std::{cell::RefCell, collections::HashSet, fmt::Debug, rc::Rc, sync::Arc},
+    std::{borrow::Cow, cell::RefCell, collections::HashSet, fmt::Debug, rc::Rc, sync::Arc},
 };
 
 /// Prototype of a native loader entry point
@@ -104,8 +105,8 @@ pub trait InvokeContext {
         execute_us: u64,
         deserialize_us: u64,
     );
-    /// Get sysvars
-    fn get_sysvars(&self) -> &[(Pubkey, Vec<u8>)];
+    /// Get sysvar cache
+    fn get_sysvar_cache(&self) -> &SysvarCache;
     /// Set the return data
     fn set_return_data(&mut self, return_data: Option<(Pubkey, Vec<u8>)>);
     /// Get the return data
@@ -149,7 +150,7 @@ pub fn get_sysvar<T: Sysvar>(
     id: &Pubkey,
 ) -> Result<T, InstructionError> {
     invoke_context
-        .get_sysvars()
+        .get_sysvar_cache()
         .iter()
         .find_map(|(key, data)| {
             if id == key {
@@ -394,7 +395,7 @@ pub struct MockInvokeContext<'a> {
     pub compute_meter: MockComputeMeter,
     pub programs: Vec<(Pubkey, ProcessInstructionWithContext)>,
     pub accounts: Vec<(Pubkey, Rc<RefCell<AccountSharedData>>)>,
-    pub sysvars: Vec<(Pubkey, Vec<u8>)>,
+    pub sysvar_cache: Cow<'a, SysvarCache>,
     pub disabled_features: HashSet<Pubkey>,
     pub return_data: Option<(Pubkey, Vec<u8>)>,
     pub execute_timings: ExecuteDetailsTimings,
@@ -412,7 +413,7 @@ impl<'a> MockInvokeContext<'a> {
             },
             programs: vec![],
             accounts: vec![],
-            sysvars: vec![],
+            sysvar_cache: Cow::Owned(SysvarCache::default()),
             disabled_features: HashSet::default(),
             return_data: None,
             execute_timings: ExecuteDetailsTimings::default(),
@@ -514,8 +515,8 @@ impl<'a> InvokeContext for MockInvokeContext<'a> {
         _deserialize_us: u64,
     ) {
     }
-    fn get_sysvars(&self) -> &[(Pubkey, Vec<u8>)] {
-        &self.sysvars
+    fn get_sysvar_cache(&self) -> &SysvarCache {
+        &self.sysvar_cache
     }
     fn set_return_data(&mut self, return_data: Option<(Pubkey, Vec<u8>)>) {
         self.return_data = return_data;

sdk/src/sysvar_cache.rs

@@ -0,0 +1,39 @@
+use {
+    solana_sdk::{
+        account::{AccountSharedData, ReadableAccount},
+        pubkey::Pubkey,
+    },
+    std::ops::Deref,
+};
+
+#[cfg(RUSTC_WITH_SPECIALIZATION)]
+impl ::solana_frozen_abi::abi_example::AbiExample for SysvarCache {
+    fn example() -> Self {
+        // SysvarCache is not Serialize so just rely on Default.
+        SysvarCache::default()
+    }
+}
+
+#[derive(Default, Clone, Debug)]
+pub struct SysvarCache(Vec<(Pubkey, Vec<u8>)>);
+
+impl Deref for SysvarCache {
+    type Target = Vec<(Pubkey, Vec<u8>)>;
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl SysvarCache {
+    pub fn push_entry(&mut self, pubkey: Pubkey, data: Vec<u8>) {
+        self.0.push((pubkey, data));
+    }
+
+    pub fn update_entry(&mut self, pubkey: &Pubkey, new_account: &AccountSharedData) {
+        if let Some(position) = self.iter().position(|(id, _data)| id == pubkey) {
+            self.0[position].1 = new_account.data().to_vec();
+        } else {
+            self.0.push((*pubkey, new_account.data().to_vec()));
+        }
+    }
+}