Adds unwrap_bump macro (#36)

* Adds unwrap_bump macro

* changelog

CHANGELOG.md

@@ -5,6 +5,12 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## Unreleased Changes
+
+### Features
+
+- Adds the `unwrap_bump!` macro, which extracts the bump from the instruction `Context` ([#36](https://github.com/saber-hq/vipers/pull/36)).
+
 ## [2.0.0] - 2022-02-21
 
 ### Features

tests/vipers-tests/src/lib.rs

@@ -1,6 +1,8 @@
 //! Vipers tests.
 #![cfg(test)]
 
+use std::collections::BTreeMap;
+
 use anchor_lang::prelude::*;
 
 declare_id!("VipersTest111111111111111111111111111111111");
@@ -23,6 +25,11 @@ struct TestData {
     pub byte: u8,
 }
 
+#[derive(Accounts)]
+struct MyAccounts<'info> {
+    random: AccountInfo<'info>,
+}
+
 #[test]
 #[allow(deprecated)]
 pub fn test_compiles_deprecated() -> Result<()> {
@@ -244,3 +251,37 @@ fn test_anchor_errors_ne_result() {
         (err!(MyOtherError) as Result<()>).into_cmp_error(),
     );
 }
+
+#[test]
+fn test_unwrap_bump() {
+    let mut lamports = 0;
+    let random: AccountInfo = AccountInfo::new(
+        &crate::ID,
+        false,
+        false,
+        &mut lamports,
+        &mut [],
+        &crate::ID,
+        false,
+        0,
+    );
+    let accounts = &mut MyAccounts { random };
+    let mut bumps: BTreeMap<String, u8> = BTreeMap::new();
+    bumps.insert("test".to_string(), 1);
+    let ctx = Context {
+        program_id: &vipers::ID,
+        accounts,
+        remaining_accounts: &[],
+        bumps,
+    };
+    assert_does_not_throw!({
+        let bump = unwrap_bump!(ctx, "test");
+        assert_eq!(bump, 1);
+    });
+    assert_throws!(
+        {
+            let _bump2 = unwrap_bump!(ctx, "missing");
+        },
+        VipersError::UnknownBump
+    );
+}

vipers/src/assert.rs

@@ -499,6 +499,31 @@ macro_rules! unwrap_int {
     };
 }
 
+/// Unwraps a bump seed.
+///
+/// # Example
+///
+/// ```ignore
+/// # use anchor_lang::prelude::*;
+/// # #[macro_use] extern crate vipers; fn main() -> Result<()> {
+/// fn my_instruction(ctx: Context<MyAccounts>) -> Result<()> {
+///     let my_data = &mut ctx.accounts.my_data
+///     my_data.bump = unwrap_bump!(ctx, "my_data");
+///     Ok(())
+/// }
+/// # }
+/// ```
+#[macro_export]
+macro_rules! unwrap_bump {
+    ($ctx:expr, $bump:literal $(,)?) => {
+        *$crate::unwrap_opt!(
+            $ctx.bumps.get($bump),
+            $crate::VipersError::UnknownBump,
+            format!("Unknown bump: {}", $bump)
+        )
+    };
+}
+
 /// Tries to unwrap the [Result], otherwise returns the error
 ///
 /// # Example

vipers/src/error.rs

@@ -27,6 +27,8 @@ pub enum VipersError {
     KeysMustNotMatch,
     #[msg("The provided token account is non-zero: amount must be zero, it should not have a delegate, and it should not have a close authority.")]
     TokenAccountIsNonZero,
+    #[msg("Bump not found.")]
+    UnknownBump,
 }
 
 /// Conversions into a [CmpError].

vipers/src/lib.rs

@@ -51,7 +51,7 @@ pub mod prelude {
 
     pub use super::{
         assert_is_zero_token_account, assert_keys_eq, assert_keys_neq, invariant, try_or_err,
-        unwrap_checked, unwrap_int, unwrap_opt, unwrap_opt_block, unwrap_or_err, AsKeyRef,
-        CmpError, IntoCmpError, Validate, VipersError,
+        unwrap_bump, unwrap_checked, unwrap_int, unwrap_opt, unwrap_opt_block, unwrap_or_err,
+        AsKeyRef, CmpError, IntoCmpError, Validate, VipersError,
     };
 }