add steel example to close account (#208)

basics/close-account/steel/.gitignore

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+target
+test-ledger

basics/close-account/steel/Cargo.toml

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+[workspace]
+members = ["api", "program"]
+resolver = "2"
+
+[workspace.package]
+version = "0.1.0"
+edition = "2021"
+license = "Apache-2.0"
+homepage = "https://github.com/solana-developers/program-examples"
+documentation = "https://github.com/solana-developers/program-examples"
+respository = "https://github.com/solana-developers/program-examples"
+readme = "./README.md"
+keywords = ["solana"]
+
+[workspace.dependencies]
+close-account-api = { path = "./api", version = "0.1.0" }
+bytemuck = "1.14"
+num_enum = "0.7"
+solana-program = "1.18"
+steel = "2.1.0"
+thiserror = "1.0"

basics/close-account/steel/README.md

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+# CloseAccount
+
+**CloseAccount** is a ...
+
+## API
+- [`Consts`](api/src/consts.rs) – Program constants.
+- [`Error`](api/src/error.rs) – Custom program errors.
+- [`Event`](api/src/event.rs) – Custom program events.
+- [`Instruction`](api/src/instruction.rs) – Declared instructions.
+
+## Instructions
+- [`Hello`](program/src/hello.rs) – Hello ...
+
+## State
+- [`User`](api/src/state/user.rs) – User ...
+
+## Tests
+
+To run the test suit, use the Solana toolchain:
+```
+cargo test-sbf         
+```

basics/close-account/steel/api/Cargo.toml

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+[package]
+name = "close-account-api"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+bytemuck.workspace = true
+jzon = "0.12.5"
+num_enum.workspace = true
+solana-program.workspace = true
+steel.workspace = true
+thiserror.workspace = true

basics/close-account/steel/api/src/error.rs

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+use steel::*;
+
+/// A [Result] type representing `Result<T, CloseAccountError>`
+pub type CloseAccountResult<T> = Result<T, CloseAccountError>;
+
+/// Error handling enum for this create
+#[derive(Debug, Error, Clone, Copy, PartialEq, Eq, IntoPrimitive)]
+#[repr(u32)]
+pub enum CloseAccountError {
+    /// A name can only be 64 bytes in length when converted to bytes
+    #[error("Invalid Name Length. The maximum length of the string is 64 bytes.")]
+    MaxNameLengthExceeded = 0,
+    /// Only UTF-8 String types are supported
+    #[error("Only UTF-8 String encoding is supported")]
+    OnlyUtf8IsSupported = 1,
+}
+
+error!(CloseAccountError);

basics/close-account/steel/api/src/instruction.rs

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+use steel::*;
+
+/// Used in generating the discriminats for instructions
+#[repr(u8)]
+#[derive(Clone, Copy, Debug, Eq, PartialEq, TryFromPrimitive)]
+pub enum MyInstruction {
+    /// Create account discriminant represented by `0`
+    CreateAccount = 0,
+    /// Close account discriminant represented by `1`
+    CloseAccount = 1,
+}
+
+/// Create account struct with the name
+/// as an array of 64 bytes
+#[repr(C)]
+#[derive(Clone, Copy, Debug, Pod, Zeroable)]
+pub struct CreateAccount(pub [u8; 64]);
+
+/// UsedClose Account
+#[repr(C)]
+#[derive(Clone, Copy, Debug, Pod, Zeroable)]
+pub struct CloseAccount;
+
+instruction!(MyInstruction, CreateAccount);
+instruction!(MyInstruction, CloseAccount);

basics/close-account/steel/api/src/lib.rs

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+#![forbid(unsafe_code)]
+
+pub mod error;
+pub mod instruction;
+pub mod sdk;
+pub mod state;
+
+pub mod prelude {
+    pub use crate::error::*;
+    pub use crate::instruction::*;
+    pub use crate::sdk::*;
+    pub use crate::state::*;
+}
+
+use steel::*;
+
+// Set program id
+declare_id!("z7msBPQHDJjTvdQRoEcKyENgXDhSRYeHieN1ZMTqo35");

basics/close-account/steel/api/src/sdk.rs

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+use steel::*;
+
+use crate::prelude::*;
+
+/// Create an PDA and store a String in it
+pub fn create_account(signer: Pubkey, user: CreateAccount) -> Instruction {
+    Instruction {
+        program_id: crate::ID,
+        accounts: vec![
+            AccountMeta::new(signer, true),
+            AccountMeta::new(User::pda(signer).0, false),
+            AccountMeta::new_readonly(system_program::ID, false),
+        ],
+        data: user.to_bytes(),
+    }
+}
+
+/// Creates an instruction to close the account,
+/// in our case the PDA. The PDA address is derived from
+/// the `payer` public key
+pub fn close_account(signer: Pubkey) -> Instruction {
+    Instruction {
+        program_id: crate::ID,
+        accounts: vec![
+            AccountMeta::new(signer, true),
+            AccountMeta::new(User::pda(signer).0, false),
+            AccountMeta::new_readonly(system_program::ID, false),
+        ],
+        data: CloseAccount.to_bytes(),
+    }
+}

basics/close-account/steel/api/src/state/mod.rs

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+mod user;
+pub use user::*;

basics/close-account/steel/api/src/state/user.rs

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+use steel::*;
+
+use crate::error::{CloseAccountError, CloseAccountResult};
+
+/// An enum which is used to derive a discriminator for the user account.
+#[repr(u8)]
+#[derive(Clone, Copy, Debug, Eq, PartialEq, IntoPrimitive, TryFromPrimitive)]
+pub enum UserAccount {
+    /// The user is represented by a discriminator of `0`
+    User = 0,
+}
+
+/// The user Account structure which stores a
+/// `name` as bytes with max array length of u64 due to the
+/// requirement for memory alignment since 64 is a factor of 8.
+#[repr(C)]
+#[derive(Clone, Copy, Debug, PartialEq, Pod, Zeroable)]
+pub struct User {
+    /// The name string stored as bytes.
+    /// The `&str` is converted into bytes and copied upto
+    /// the length of the bytes, if the bytes are not 64, it
+    /// pads with zeroes upto 64, if it is more than 64 an error
+    /// is returned.
+    pub name: [u8; 64],
+}
+
+impl User {
+    /// Seed for the [User] used to in PDA generation
+    pub const SEED_PREFIX: &'static str = "USER";
+
+    /// Create a new user, convert the name into bytes
+    /// and add those bytes to a 64 byte array
+    pub fn new(name: &str) -> CloseAccountResult<Self> {
+        let name_bytes = name.as_bytes();
+
+        Self::check_length(name_bytes)?;
+
+        let mut name = [0u8; 64];
+        name[0..name_bytes.len()].copy_from_slice(name_bytes);
+
+        Ok(Self { name })
+    }
+
+    /// Converts the byte array into a UTF-8 [str]
+    /// using the `trim_end_matches("\0")` of [str] method
+    /// to remove padded zeroes if any. Padded zeroes are
+    /// represented by `\0`
+    pub fn to_string(&self) -> CloseAccountResult<String> {
+        let value =
+            core::str::from_utf8(&self.name).map_err(|_| CloseAccountError::OnlyUtf8IsSupported)?;
+
+        Ok(value.trim_end_matches("\0").to_string())
+    }
+
+    fn check_length(bytes: &[u8]) -> CloseAccountResult<()> {
+        if bytes.len() > 64 {
+            return Err(CloseAccountError::MaxNameLengthExceeded);
+        }
+
+        Ok(())
+    }
+
+    /// Generate a PDA from the [Self::SEED_PREFIX] constant
+    /// and the payer public key. This returns a tuple struct
+    /// ([Pubkey], [u8])
+    pub fn pda(payer: Pubkey) -> (Pubkey, u8) {
+        Pubkey::try_find_program_address(
+            &[Self::SEED_PREFIX.as_bytes(), payer.as_ref()],
+            &crate::id(),
+        )
+        .unwrap()
+    }
+}
+
+account!(UserAccount, User);

basics/close-account/steel/cicd.sh

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+#!/bin/bash
+
+# This script is for quick building & deploying of the program.
+# It also serves as a reference for the commands used for building & deploying Solana programs.
+# Run this bad boy with "bash cicd.sh" or "./cicd.sh"
+
+cargo build-sbf --manifest-path=./program/Cargo.toml --bpf-out-dir=./program/target/so
+solana program deploy ./program/target/so/program.so

basics/close-account/steel/package.json

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+{
+  "scripts": {
+    "test": "pnpm ts-mocha -p ./tests/tsconfig.test.json -t 1000000 ./tests/close-account.test.ts",
+    "build-and-test": "cargo build-sbf --manifest-path=./program/Cargo.toml --sbf-out-dir=./tests/fixtures && pnpm test",
+    "build": "cargo build-sbf --manifest-path=./program/Cargo.toml --sbf-out-dir=./target/so",
+    "deploy": "solana program deploy ./target/so/close_account_program.so"
+  },
+  "dependencies": {
+    "@coral-xyz/borsh": "^0.30.1",
+    "@solana/web3.js": "^1.35"
+  },
+  "devDependencies": {
+    "solana-bankrun": "^0.4.0",
+    "typescript": "^5.6.3",
+    "ts-mocha": "^10.0.0"
+  },
+  "packageManager": "[email protected]+sha512.60c18acd138bff695d339be6ad13f7e936eea6745660d4cc4a776d5247c540d0edee1a563695c183a66eb917ef88f2b4feb1fc25f32a7adcadc7aaf3438e99c1"
+}