siexp · April 29, 2024 16:45 · Apr 29, 2024 · Apr 29, 2024 · Apr 29, 2024
diff --git a/hello_world.rs → lib.rs b/hello_world.rs → lib.rs
diff --git a/hello_world.rs b/hello_world.rs
@@ -0,0 +1,108 @@
+use borsh::{BorshSerialize, BorshDeserialize};
+use solana_program::{
+    account_info::{next_account_info, AccountInfo},
+    entrypoint,
+    msg,
+    entrypoint::ProgramResult,
+    program_error::ProgramError,
+    pubkey::Pubkey,
+};
+
+/// Define the type of state stored in accounts
+#[derive(BorshSerialize, BorshDeserialize, Debug)]
+pub struct GreetingAccount {
+    /// number of greetings
+    pub counter: u32,
+}
+
+// Declare and export the program's entrypoint
+entrypoint!(process_instruction);
+
+pub fn process_instruction(
+    program_id: &Pubkey,
+    accounts: &[AccountInfo],
+    _instruction_data: &[u8],
+) -> ProgramResult {
+    msg!("Rust program entrypoint");
+    // Iterating accounts is safer than indexing
+    let accounts_iter =&mut accounts.iter();
+    // Get the account to say hello to
+    let account = next_account_info(accounts_iter)?;
+    // The account must be owned by the program in order to modify its data
+    if account.owner != program_id {
+        msg!("Greeted account {} does not have the correct program id", account.owner);
+        return Err(ProgramError::IncorrectProgramId);
+    } else {
+        msg!("Greeted account {} have correct program id", account.owner);
+    }
+
+    let mut greeting_data = GreetingAccount::try_from_slice(&account.data.borrow())?;
+    greeting_data.counter += 1;
+    greeting_data.serialize(&mut &mut account.data.borrow_mut()[..])?;
+
+    msg!("Greeted {} time(s)!", greeting_data.counter);
+
+    Ok(())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use solana_program::clock::Epoch;
+    use std::mem;
+    use borsh::{from_slice, to_vec};
+
+    #[test]
+    fn test_greeting_from_slice() {
+        let key = Pubkey::default();
+        let mut lamports = 0;
+        let mut data = vec![0; mem::size_of::<u32>()];
+        let owner = Pubkey::default();
+        let account = AccountInfo::new(
+            &key,
+            false,
+            true,
+            &mut lamports,
+            &mut data,
+            &owner,
+            false,
+            Epoch::default(),
+        );
+        let accounts = [account];
+        let mut greeting_array = accounts[0].data.try_borrow_mut().unwrap();
+        let mut greeting_data: GreetingAccount = from_slice::<GreetingAccount>(&greeting_array[..]).unwrap();
+        assert_eq!(greeting_data.counter, 0);
+        greeting_data.counter += 1;
+        greeting_array[..].copy_from_slice(&to_vec(&greeting_data).unwrap());
+        assert_eq!(greeting_data.counter, 1);
+    }
+
+    #[test]
+    fn test_sanity() {
+        let program_id = Pubkey::default();
+        let key = Pubkey::default();
+        let mut lamports = 0;
+        let mut data = vec![0; mem::size_of::<u32>()];
+        let owner = Pubkey::default();
+        let account = AccountInfo::new(
+            &key,
+            false,
+            true,
+            &mut lamports,
+            &mut data,
+            &owner,
+            false,
+            Epoch::default(),
+        );
+        let accounts = vec![account];
+        let greeting_array = accounts[0].data.try_borrow().unwrap();
+        let greeting_data: GreetingAccount = from_slice::<GreetingAccount>(&greeting_array[..]).unwrap();
+        assert_eq!(greeting_data.counter, 0);
+
+        let instruction_data: Vec<u8> = Vec::new();
+        process_instruction(&program_id, &accounts, &instruction_data).unwrap();
+        let greeting_array1 = accounts[0].data.try_borrow().unwrap();
+        let greeting_data1: GreetingAccount = from_slice::<GreetingAccount>(&greeting_array1[..]).unwrap();
+        assert_eq!(greeting_data1.counter, 1);
+    }
+}