Rename program_utils.rs (#8127)

sdk/src/program_utils.rs

@@ -0,0 +1,75 @@
+use crate::{
+    account::KeyedAccount, account_info::AccountInfo, instruction::InstructionError,
+    program_error::ProgramError,
+};
+use num_traits::FromPrimitive;
+
+/// Return the next KeyedAccount or a NotEnoughAccountKeys error
+pub fn next_keyed_account<'a, 'b, I: Iterator<Item = &'a KeyedAccount<'b>>>(
+    iter: &mut I,
+) -> Result<I::Item, InstructionError> {
+    iter.next().ok_or(InstructionError::NotEnoughAccountKeys)
+}
+
+/// Return the next AccountInfo or a NotEnoughAccountKeys error
+pub fn next_account_info<'a, 'b, I: Iterator<Item = &'a AccountInfo<'b>>>(
+    iter: &mut I,
+) -> Result<I::Item, ProgramError> {
+    iter.next().ok_or(ProgramError::NotEnoughAccountKeys)
+}
+
+/// Return true if the first keyed_account is executable, used to determine if
+/// the loader should call a program's 'main'
+pub fn is_executable(keyed_accounts: &[KeyedAccount]) -> Result<bool, InstructionError> {
+    Ok(!keyed_accounts.is_empty() && keyed_accounts[0].executable()?)
+}
+
+/// Deserialize with a limit based the maximum amount of data a program can expect to get.
+/// This function should be used in place of direct deserialization to help prevent OOM errors
+pub fn limited_deserialize<T>(instruction_data: &[u8]) -> Result<T, InstructionError>
+where
+    T: serde::de::DeserializeOwned,
+{
+    let limit = crate::packet::PACKET_DATA_SIZE as u64;
+    bincode::config()
+        .limit(limit)
+        .deserialize(instruction_data)
+        .map_err(|_| InstructionError::InvalidInstructionData)
+}
+
+/// Allows customer errors to be decoded back to their original enum
+pub trait DecodeError<E> {
+    fn decode_custom_error_to_enum(custom: u32) -> Option<E>
+    where
+        E: FromPrimitive,
+    {
+        E::from_u32(custom)
+    }
+    fn type_of() -> &'static str;
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use num_derive::FromPrimitive;
+
+    #[test]
+    fn test_decode_custom_error_to_enum() {
+        #[derive(Debug, FromPrimitive, PartialEq)]
+        enum TestEnum {
+            A,
+            B,
+            C,
+        }
+        impl<T> DecodeError<T> for TestEnum {
+            fn type_of() -> &'static str {
+                "TestEnum"
+            }
+        }
+        assert_eq!(TestEnum::decode_custom_error_to_enum(0), Some(TestEnum::A));
+        assert_eq!(TestEnum::decode_custom_error_to_enum(1), Some(TestEnum::B));
+        assert_eq!(TestEnum::decode_custom_error_to_enum(2), Some(TestEnum::C));
+        let option: Option<TestEnum> = TestEnum::decode_custom_error_to_enum(3);
+        assert_eq!(option, None);
+    }
+}