feature gate: add activate instruction

feature-gate/README.md

@@ -2,7 +2,8 @@
 
 This program serves to manage new features on Solana.
 
-It serves one purpose: revoking features that are pending activation.
+It serves two main purposes: activating new features and revoking features that
+are pending activation.
 
 More information & documentation will follow as this program matures, but you
 can follow the discussions

feature-gate/program/Cargo.toml

@@ -17,8 +17,8 @@ solana-program = "1.16.16"
 spl-program-error = { version = "0.3.0", path = "../../libraries/program-error" }
 
 [dev-dependencies]
-solana-program-test = "1.16.16"
 solana-sdk = "1.16.16"
+solana-program-test = "1.16.16"
 
 [lib]
 crate-type = ["cdylib", "lib"]

feature-gate/program/src/error.rs

@@ -11,4 +11,10 @@ pub enum FeatureGateError {
     /// Feature already activated
     #[error("Feature already activated")]
     FeatureAlreadyActivated,
+    /// Incorrect feature ID
+    #[error("Incorrect feature ID")]
+    IncorrectFeatureId,
+    /// Invalid feature account
+    #[error("Invalid feature account")]
+    InvalidFeatureAccount,
 }

feature-gate/program/src/feature_id.rs

@@ -0,0 +1,37 @@
+//! Module for managing feature IDs
+
+// use {
+//     crate::error::FeatureGateError,
+//     solana_program::{program_error::ProgramError, pubkey::Pubkey},
+//     solana_sdk::feature_set::FEATURE_NAMES,
+// };
+
+// /// Returns `true` if the feature ID exists in the current feature set.
+// fn feature_exists(feature_id: &Pubkey) -> bool {
+//     FEATURE_NAMES.iter().any(|(id, _)| id == feature_id)
+// }
+
+// /// Derives the feature ID from a authority's address.
+// pub fn derive_feature_id(authority: &Pubkey) -> Result<Pubkey, ProgramError> {
+//     let nonce = 0u16; // u16::MAX = 65_535 features!
+//     let mut feature_id = Pubkey::find_program_address(&[b"feature"], &crate::id()).0;
+//     while feature_exists(&feature_id) {
+//         nonce.checked_add(1).ok_or(FeatureGateError::Overflow)?;
+//         feature_id = Pubkey::find_program_address(
+//             &[b"feature", &nonce.to_le_bytes(), &authority.to_bytes()],
+//             &crate::id(),
+//         )
+//         .0;
+//     }
+//     Ok(feature_id)
+// }
+
+use solana_program::{program_error::ProgramError, pubkey::Pubkey};
+
+/// Derives the feature ID from a authority's address.
+pub fn derive_feature_id(authority: &Pubkey) -> Result<(Pubkey, u8), ProgramError> {
+    Ok(Pubkey::find_program_address(
+        &[b"feature", authority.as_ref()],
+        &crate::id(),
+    ))
+}

feature-gate/program/src/instruction.rs

@@ -3,16 +3,33 @@
 use {
     num_enum::{IntoPrimitive, TryFromPrimitive},
     solana_program::{
+        feature::Feature,
         instruction::{AccountMeta, Instruction},
         program_error::ProgramError,
         pubkey::Pubkey,
+        rent::Rent,
+        system_instruction, system_program,
     },
 };
 
 /// Feature Gate program instructions
 #[derive(Clone, Debug, PartialEq, IntoPrimitive, TryFromPrimitive)]
 #[repr(u8)]
 pub enum FeatureGateInstruction {
+    /// Submit a feature for activation.
+    ///
+    /// Note: This instruction expects the account to exist and be owned by the
+    /// system program. The account should also have enough rent-exempt lamports
+    /// to cover the cost of the account creation for a
+    /// `solana_program::feature::Feature` state prior to invoking this
+    /// instruction.
+    ///
+    /// Accounts expected by this instruction:
+    ///
+    ///   0. `[w]`  Feature account (must be a system account)
+    ///   1. `[s]`  Feature activation authority (can be multisig)
+    ///   2. `[]`   System program
+    ActivateFeature,
     /// Revoke a pending feature activation.
     ///
     /// A "pending" feature activation is a feature account that has been
@@ -23,8 +40,8 @@ pub enum FeatureGateInstruction {
     ///
     /// Accounts expected by this instruction:
     ///
-    ///   0. `[w+s]` Feature account
-    ///   1. `[w]` Destination (for rent lamports)
+    ///   0. `[w]`      Feature account
+    ///   1. `[w+s]`    Feature activation authority (can be multisig)
     RevokePendingActivation,
 }
 impl FeatureGateInstruction {
@@ -44,11 +61,42 @@ impl FeatureGateInstruction {
     }
 }
 
+/// Creates an 'ActivateFeature' instruction.
+pub fn activate_feature(feature_id: &Pubkey, authority: &Pubkey) -> Instruction {
+    let accounts = vec![
+        AccountMeta::new(*feature_id, false),
+        AccountMeta::new_readonly(*authority, true),
+        AccountMeta::new_readonly(system_program::id(), false),
+    ];
+
+    let data = FeatureGateInstruction::ActivateFeature.pack();
+
+    Instruction {
+        program_id: crate::id(),
+        accounts,
+        data,
+    }
+}
+
+/// Creates a set of two instructions:
+///   * One to fund the feature account with rent-exempt lamports
+///   * Another is the Feature Gate Program's 'ActivateFeature' instruction
+pub fn activate_feature_with_rent_transfer(
+    feature_id: &Pubkey,
+    authority: &Pubkey,
+) -> [Instruction; 2] {
+    let lamports = Rent::default().minimum_balance(Feature::size_of());
+    [
+        system_instruction::transfer(authority, feature_id, lamports),
+        activate_feature(feature_id, authority),
+    ]
+}
+
 /// Creates a 'RevokePendingActivation' instruction.
-pub fn revoke_pending_activation(feature: &Pubkey, destination: &Pubkey) -> Instruction {
+pub fn revoke_pending_activation(feature_id: &Pubkey, authority: &Pubkey) -> Instruction {
     let accounts = vec![
-        AccountMeta::new(*feature, true),
-        AccountMeta::new(*destination, false),
+        AccountMeta::new(*feature_id, false),
+        AccountMeta::new(*authority, true),
     ];
 
     let data = FeatureGateInstruction::RevokePendingActivation.pack();
@@ -70,6 +118,11 @@ mod test {
         assert_eq!(instruction, &unpacked);
     }
 
+    #[test]
+    fn test_pack_unpack_activate() {
+        test_pack_unpack(&FeatureGateInstruction::ActivateFeature);
+    }
+
     #[test]
     fn test_pack_unpack_revoke() {
         test_pack_unpack(&FeatureGateInstruction::RevokePendingActivation);

feature-gate/program/src/lib.rs

@@ -6,6 +6,7 @@
 #[cfg(not(feature = "no-entrypoint"))]
 mod entrypoint;
 pub mod error;
+pub mod feature_id;
 pub mod instruction;
 pub mod processor;
 

feature-gate/program/src/processor.rs

@@ -1,18 +1,58 @@
 //! Program state processor
 
 use {
-    crate::{error::FeatureGateError, instruction::FeatureGateInstruction},
+    crate::{
+        error::FeatureGateError, feature_id::derive_feature_id, instruction::FeatureGateInstruction,
+    },
     solana_program::{
         account_info::{next_account_info, AccountInfo},
         entrypoint::ProgramResult,
         feature::Feature,
         msg,
+        program::invoke_signed,
         program_error::ProgramError,
         pubkey::Pubkey,
-        system_program,
+        system_instruction, system_program,
     },
 };
 
+/// Processes an [ActivateFeature](enum.FeatureGateInstruction.html)
+/// instruction.
+pub fn process_activate_feature(program_id: &Pubkey, accounts: &[AccountInfo]) -> ProgramResult {
+    let account_info_iter = &mut accounts.iter();
+
+    let feature_info = next_account_info(account_info_iter)?;
+    let authority_info = next_account_info(account_info_iter)?;
+    let _system_program_info = next_account_info(account_info_iter)?;
+
+    if !authority_info.is_signer {
+        return Err(ProgramError::MissingRequiredSignature);
+    }
+
+    if feature_info.owner != &system_program::id() {
+        return Err(FeatureGateError::InvalidFeatureAccount.into());
+    }
+
+    let (feature_id, feature_id_bump) = derive_feature_id(authority_info.key)?;
+
+    if feature_info.key != &feature_id {
+        return Err(FeatureGateError::IncorrectFeatureId.into());
+    }
+
+    invoke_signed(
+        &system_instruction::allocate(feature_info.key, Feature::size_of() as u64),
+        &[feature_info.clone()],
+        &[&[b"feature", authority_info.key.as_ref(), &[feature_id_bump]]],
+    )?;
+    invoke_signed(
+        &system_instruction::assign(feature_info.key, program_id),
+        &[feature_info.clone()],
+        &[&[b"feature", authority_info.key.as_ref(), &[feature_id_bump]]],
+    )?;
+
+    Ok(())
+}
+
 /// Processes an [RevokePendingActivation](enum.FeatureGateInstruction.html)
 /// instruction.
 pub fn process_revoke_pending_activation(
@@ -22,9 +62,9 @@ pub fn process_revoke_pending_activation(
     let account_info_iter = &mut accounts.iter();
 
     let feature_info = next_account_info(account_info_iter)?;
-    let destination_info = next_account_info(account_info_iter)?;
+    let authority_info = next_account_info(account_info_iter)?;
 
-    if !feature_info.is_signer {
+    if !authority_info.is_signer {
         return Err(ProgramError::MissingRequiredSignature);
     }
 
@@ -39,13 +79,13 @@ pub fn process_revoke_pending_activation(
         return Err(FeatureGateError::FeatureAlreadyActivated.into());
     }
 
-    let new_destination_lamports = feature_info
+    let new_authority_lamports = feature_info
         .lamports()
-        .checked_add(destination_info.lamports())
+        .checked_add(authority_info.lamports())
         .ok_or::<ProgramError>(FeatureGateError::Overflow.into())?;
 
     **feature_info.try_borrow_mut_lamports()? = 0;
-    **destination_info.try_borrow_mut_lamports()? = new_destination_lamports;
+    **authority_info.try_borrow_mut_lamports()? = new_authority_lamports;
 
     feature_info.realloc(0, true)?;
     feature_info.assign(&system_program::id());
@@ -57,6 +97,10 @@ pub fn process_revoke_pending_activation(
 pub fn process(program_id: &Pubkey, accounts: &[AccountInfo], input: &[u8]) -> ProgramResult {
     let instruction = FeatureGateInstruction::unpack(input)?;
     match instruction {
+        FeatureGateInstruction::ActivateFeature => {
+            msg!("Instruction: ActivateFeature");
+            process_activate_feature(program_id, accounts)
+        }
         FeatureGateInstruction::RevokePendingActivation => {
             msg!("Instruction: RevokePendingActivation");
             process_revoke_pending_activation(program_id, accounts)