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Smart Contract Types Specification

Smart Contract Overview​

Savitri Network implements a custom smart contract platform with a sophisticated type system, upgrade mechanisms, and execution environment. The platform is designed for enterprise-grade applications with emphasis on security, performance, and upgradability.

Technology Choice Rationale​

Why Custom Smart Contract Platform​

Problem Statement: EVM compatibility imposes significant limitations on performance, security, and feature flexibility for enterprise applications requiring advanced capabilities.

Chosen Solution: Custom smart contract platform with optimized execution environment, enhanced security features, and enterprise-grade upgrade mechanisms.

Rationale:

  • Performance: Native execution without EVM overhead, SIMD optimization support
  • Security: Advanced security features beyond EVM capabilities
  • Flexibility: Custom features tailored for enterprise needs
  • Upgradability: Sophisticated upgrade mechanisms without breaking compatibility

Expected Results:

  • 5-10x performance improvement over EVM-based contracts
  • Enhanced security through custom validation and sandboxing
  • Enterprise-grade features like role-based access control
  • Seamless upgrade capabilities without contract migration

Why Base Contract Architecture​

Problem Statement: Traditional smart contracts lack standardized interfaces and upgrade mechanisms, leading to fragmentation and maintenance challenges.

Chosen Solution: Base Contract architecture with reserved storage slots, standard interfaces, and built-in upgrade capabilities.

Rationale:

  • Standardization: Consistent contract interfaces across the ecosystem
  • Upgradability: Built-in upgrade mechanisms with storage preservation
  • Security: Reserved slots prevent storage conflicts and attacks
  • Interoperability: Standard interfaces enable contract composition

Expected Results:

  • Reduced development complexity through standard interfaces
  • Seamless contract upgrades without breaking existing functionality
  • Enhanced security through standardized storage layout
  • Improved ecosystem interoperability

Contract Type System​

Base Contract​

#[derive(Debug, Clone)]
pub struct BaseContract {
    pub owner: [u8; 32],                     // Contract owner (32 bytes)
    pub version: u64,                        // Contract version (8 bytes)
    pub paused: bool,                        // Pause state (1 byte)
    pub upgrade_enabled: bool,               // Upgrade enabled flag (1 byte)
    pub access_control: AccessControl,       // Access control system
    pub metadata: ContractMetadata,         // Contract metadata
}

impl BaseContract {
    // Reserved storage slots 0-99 for BaseContract
    pub const OWNER_SLOT: u64 = 0;           // Owner address
    pub const VERSION_SLOT: u64 = 1;         // Version number
    pub const PAUSED_SLOT: u64 = 2;          // Pause state
    pub const UPGRADE_ENABLED_SLOT: u64 = 3; // Upgrade enabled
    pub const ACCESS_CONTROL_SLOT: u64 = 4;  // Access control
    pub const METADATA_SLOT: u64 = 5;        // Metadata
    
    pub const BASE_CONTRACT_SLOT_START: u64 = 0;
    pub const BASE_CONTRACT_SLOT_END: u64 = 99;
    
    pub fn new(owner: [u8; 32]) -> Self {
        Self {
            owner,
            version: 1,
            paused: false,
            upgrade_enabled: true,
            access_control: AccessControl::new(owner),
            metadata: ContractMetadata::default(),
        }
    }
    
    pub fn is_owner(&self, address: &[u8; 32]) -> bool {
        self.owner == *address
    }
    
    pub fn can_upgrade(&self, caller: &[u8; 32]) -> bool {
        self.upgrade_enabled && self.is_owner(caller)
    }
    
    pub fn is_paused(&self) -> bool {
        self.paused
    }
    
    pub fn set_paused(&mut self, paused: bool) -> Result<(), ContractError> {
        self.paused = paused;
        Ok(())
    }
}

Contract Types​

1. Token Contract​

#[derive(Debug, Clone)]
pub struct TokenContract {
    pub base: BaseContract,                   // Base contract functionality
    pub token_info: TokenInfo,                // Token information
    pub balances: HashMap<[u8; 32], u128>,    // Account balances
    pub allowances: HashMap<([u8; 32], [u8; 32]), u128>, // Allowances
    pub total_supply: u128,                  // Total supply
    pub minting_enabled: bool,               // Minting enabled
    pub burning_enabled: bool,                // Burning enabled
}

#[derive(Debug, Clone)]
pub struct TokenInfo {
    pub name: String,                         // Token name
    pub symbol: String,                       // Token symbol
    pub decimals: u8,                         // Decimal places
    pub total_supply: u128,                   // Total supply
    pub mint_cap: Option<u128>,               // Minting cap
}

impl TokenContract {
    pub fn new(owner: [u8; 32], token_info: TokenInfo) -> Self {
        Self {
            base: BaseContract::new(owner),
            token_info,
            balances: HashMap::new(),
            allowances: HashMap::new(),
            total_supply: 0,
            minting_enabled: true,
            burning_enabled: true,
        }
    }
    
    pub fn transfer(&mut self, from: [u8; 32], to: [u8; 32], amount: u128) -> Result<(), TokenError> {
        // 1. Validate transfer
        if from == to {
            return Err(TokenError::SelfTransfer);
        }
        
        if amount == 0 {
            return Err(TokenError::ZeroAmount);
        }
        
        // 2. Check balance
        let from_balance = self.balances.get(&from).unwrap_or(&0);
        if *from_balance < amount {
            return Err(TokenError::InsufficientBalance);
        }
        
        // 3. Update balances
        *self.balances.entry(from).or_insert(0) -= amount;
        *self.balances.entry(to).or_insert(0) += amount;
        
        Ok(())
    }
    
    pub fn approve(&mut self, owner: [u8; 32], spender: [u8; 32], amount: u128) -> Result<(), TokenError> {
        self.allowances.insert((owner, spender), amount);
        Ok(())
    }
    
    pub fn transfer_from(&mut self, spender: [u8; 32], from: [u8; 32], to: [u8; 32], amount: u128) -> Result<(), TokenError> {
        // 1. Check allowance
        let allowance = self.allowances.get(&(from, spender)).unwrap_or(&0);
        if *allowance < amount {
            return Err(TokenError::InsufficientAllowance);
        }
        
        // 2. Update allowance
        *self.allowances.entry((from, spender)).or_insert(0) -= amount;
        
        // 3. Perform transfer
        self.transfer(from, to, amount)?;
        
        Ok(())
    }
    
    pub fn mint(&mut self, to: [u8; 32], amount: u128) -> Result<(), TokenError> {
        if !self.minting_enabled {
            return Err(TokenError::MintingDisabled);
        }
        
        if let Some(cap) = self.token_info.mint_cap {
            if self.total_supply + amount > cap {
                return Err(TokenError::MintCapExceeded);
            }
        }
        
        self.total_supply += amount;
        *self.balances.entry(to).or_insert(0) += amount;
        
        Ok(())
    }
    
    pub fn burn(&mut self, from: [u8; 32], amount: u128) -> Result<(), TokenError> {
        if !self.burning_enabled {
            return Err(TokenError::BurningDisabled);
        }
        
        let balance = self.balances.get(&from).unwrap_or(&0);
        if *balance < amount {
            return Err(TokenError::InsufficientBalance);
        }
        
        self.total_supply -= amount;
        *self.balances.entry(from).or_insert(0) -= amount;
        
        Ok(())
    }
}

2. Governance Contract​

#[derive(Debug, Clone)]
pub struct GovernanceContract {
    pub base: BaseContract,                   // Base contract functionality
    pub proposals: HashMap<u64, Proposal>,    // Proposals by ID
    pub votes: HashMap<u64, Vec<Vote>>,       // Votes by proposal ID
    pub voting_power: HashMap<[u8; 32], u128>, // Voting power
    pub quorum: u128,                         // Quorum requirement
    pub voting_period: Duration,              // Voting period
    pub execution_delay: Duration,            // Execution delay
    pub proposal_count: u64,                  // Proposal counter
}

#[derive(Debug, Clone)]
pub struct Proposal {
    pub id: u64,                             // Proposal ID
    pub proposer: [u8; 32],                  // Proposer address
    pub title: String,                       // Proposal title
    pub description: String,                  // Proposal description
    pub actions: Vec<ProposalAction>,        // Proposal actions
    pub start_time: u64,                     // Voting start time
    pub end_time: u64,                       // Voting end time
    pub status: ProposalStatus,              // Proposal status
    pub for_votes: u128,                     // Votes for
    pub against_votes: u128,                 // Votes against
    pub abstain_votes: u128,                 // Abstain votes
}

#[derive(Debug, Clone)]
pub enum ProposalAction {
    TransferToken {
        token: [u8; 32],                     // Token contract address
        to: [u8; 32],                        // Recipient
        amount: u128,                        // Amount
    },
    CallContract {
        target: [u8; 32],                    // Target contract
        data: Vec<u8>,                       // Call data
        value: u128,                         // ETH value
    },
    UpdateParameter {
        parameter: String,                   // Parameter name
        value: Vec<u8>,                      // New value
    },
    UpgradeContract {
        target: [u8; 32],                    // Target contract
        new_bytecode: Vec<u8>,               // New bytecode
    },
}

#[derive(Debug, Clone, PartialEq, Eq)]
pub enum ProposalStatus {
    Pending,                                 // Pending voting
    Active,                                  // Active voting
    Passed,                                  // Proposal passed
    Rejected,                                // Proposal rejected
    Executed,                                // Proposal executed
    Cancelled,                               // Proposal cancelled
}

#[derive(Debug, Clone)]
pub struct Vote {
    pub voter: [u8; 32],                     // Voter address
    pub proposal_id: u64,                    // Proposal ID
    pub vote_type: VoteType,                 // Vote type
    pub voting_power: u128,                  // Voting power used
    pub timestamp: u64,                      // Vote timestamp
    pub reason: Option<String>,              // Vote reason
}

#[derive(Debug, Clone, PartialEq, Eq)]
pub enum VoteType {
    For,                                     // Vote for
    Against,                                 // Vote against
    Abstain,                                 // Abstain
}

impl GovernanceContract {
    pub fn new(owner: [u8; 32], quorum: u128, voting_period: Duration, execution_delay: Duration) -> Self {
        Self {
            base: BaseContract::new(owner),
            proposals: HashMap::new(),
            votes: HashMap::new(),
            voting_power: HashMap::new(),
            quorum,
            voting_period,
            execution_delay,
            proposal_count: 0,
        }
    }
    
    pub fn create_proposal(&mut self, proposer: [u8; 32], title: String, description: String, actions: Vec<ProposalAction>) -> Result<u64, GovernanceError> {
        let proposal_id = self.proposal_count;
        let current_time = current_timestamp();
        
        let proposal = Proposal {
            id: proposal_id,
            proposer,
            title,
            description,
            actions,
            start_time: current_time,
            end_time: current_time + self.voting_period.as_secs(),
            status: ProposalStatus::Pending,
            for_votes: 0,
            against_votes: 0,
            abstain_votes: 0,
        };
        
        self.proposals.insert(proposal_id, proposal);
        self.proposal_count += 1;
        
        Ok(proposal_id)
    }
    
    pub fn vote(&mut self, voter: [u8; 32], proposal_id: u64, vote_type: VoteType, voting_power: u128) -> Result<(), GovernanceError> {
        // 1. Validate proposal
        let proposal = self.proposals.get_mut(&proposal_id)
            .ok_or(GovernanceError::ProposalNotFound)?;
        
        // 2. Check voting period
        let current_time = current_timestamp();
        if current_time < proposal.start_time || current_time > proposal.end_time {
            return Err(GovernanceError::VotingPeriodEnded);
        }
        
        // 3. Check if already voted
        if self.has_voted(voter, proposal_id) {
            return Err(GovernanceError::AlreadyVoted);
        }
        
        // 4. Check voting power
        let available_power = self.voting_power.get(&voter).unwrap_or(&0);
        if *available_power < voting_power {
            return Err(GovernanceError::InsufficientVotingPower);
        }
        
        // 5. Record vote
        let vote = Vote {
            voter,
            proposal_id,
            vote_type,
            voting_power,
            timestamp: current_time,
            reason: None,
        };
        
        self.votes.entry(proposal_id).or_insert_with(Vec::new).push(vote);
        
        // 6. Update proposal vote counts
        match vote_type {
            VoteType::For => proposal.for_votes += voting_power,
            VoteType::Against => proposal.against_votes += voting_power,
            VoteType::Abstain => proposal.abstain_votes += voting_power,
        }
        
        Ok(())
    }
    
    pub fn execute_proposal(&mut self, executor: [u8; 32], proposal_id: u64) -> Result<(), GovernanceError> {
        let proposal = self.proposals.get(&proposal_id)
            .ok_or(GovernanceError::ProposalNotFound)?;
        
        // 1. Check if proposal passed
        if proposal.status != ProposalStatus::Passed {
            return Err(GovernanceError::ProposalNotPassed);
        }
        
        // 2. Check execution delay
        let current_time = current_timestamp();
        if current_time < proposal.end_time + self.execution_delay.as_secs() {
            return Err(GovernanceError::ExecutionDelayNotMet);
        }
        
        // 3. Execute proposal actions
        for action in &proposal.actions {
            self.execute_action(action, executor)?;
        }
        
        // 4. Update proposal status
        if let Some(p) = self.proposals.get_mut(&proposal_id) {
            p.status = ProposalStatus::Executed;
        }
        
        Ok(())
    }
    
    fn execute_action(&self, action: &ProposalAction, executor: [u8; 32]) -> Result<(), GovernanceError> {
        match action {
            ProposalAction::TransferToken { token, to, amount } => {
                // Execute token transfer
                self.call_contract(*token, &self.encode_transfer(*to, *amount))?;
            },
            ProposalAction::CallContract { target, data, value } => {
                // Execute contract call
                self.call_contract(*target, data)?;
            },
            ProposalAction::UpdateParameter { parameter, value } => {
                // Update parameter
                self.update_parameter(parameter, value)?;
            },
            ProposalAction::UpgradeContract { target, new_bytecode } => {
                // Upgrade contract
                self.upgrade_contract(*target, new_bytecode.clone())?;
            },
        }
        Ok(())
    }
}

3. DeFi Contract​

#[derive(Debug, Clone)]
pub struct DeFiContract {
    pub base: BaseContract,                   // Base contract functionality
    pub pools: HashMap<[u8; 32], LiquidityPool>, // Liquidity pools
    pub positions: HashMap<[u8; 32], Vec<Position>>, // User positions
    pub oracle: PriceOracle,                  // Price oracle
    pub fees: FeeConfig,                      // Fee configuration
    pub governance: [u8; 32],                 // Governance contract
}

#[derive(Debug, Clone)]
pub struct LiquidityPool {
    pub token_a: [u8; 32],                   // Token A address
    pub token_b: [u8; 32],                   // Token B address
    pub reserve_a: u128,                      // Reserve A
    pub reserve_b: u128,                      // Reserve B
    pub total_liquidity: u128,                // Total liquidity
    pub fee_rate: u64,                        // Fee rate (basis points)
    pub lp_token: [u8; 32],                  // LP token address
}

#[derive(Debug, Clone)]
pub struct Position {
    pub owner: [u8; 32],                     // Position owner
    pub pool: [u8; 32],                      // Pool address
    pub liquidity: u128,                     // Liquidity amount
    pub tick_lower: i32,                     // Lower tick
    pub tick_upper: i32,                     // Upper tick
    pub tokens_owed_a: u128,                 // Tokens A owed
    pub tokens_owed_b: u128,                 // Tokens B owed
}

impl DeFiContract {
    pub fn new(owner: [u8; 32], oracle: PriceOracle, fees: FeeConfig) -> Self {
        Self {
            base: BaseContract::new(owner),
            pools: HashMap::new(),
            positions: HashMap::new(),
            oracle,
            fees,
            governance: owner,
        }
    }
    
    pub fn create_pool(&mut self, token_a: [u8; 32], token_b: [u8; 32], fee_rate: u64) -> Result<[u8; 32], DeFiError> {
        // 1. Validate tokens
        if token_a == token_b {
            return Err(DeFiError::IdenticalTokens);
        }
        
        // 2. Create LP token
        let lp_token = self.create_lp_token(token_a, token_b)?;
        
        // 3. Create pool
        let pool = LiquidityPool {
            token_a,
            token_b,
            reserve_a: 0,
            reserve_b: 0,
            total_liquidity: 0,
            fee_rate,
            lp_token,
        };
        
        let pool_address = self.generate_pool_address(token_a, token_b, fee_rate);
        self.pools.insert(pool_address, pool);
        
        Ok(pool_address)
    }
    
    pub fn add_liquidity(&mut self, user: [u8; 32], pool_address: [u8; 32], amount_a: u128, amount_b: u128) -> Result<u128, DeFiError> {
        let pool = self.pools.get_mut(&pool_address)
            .ok_or(DeFiError::PoolNotFound)?;
        
        // 1. Calculate optimal amount
        let optimal_amount_b = self.calculate_optimal_amount(amount_a, pool.reserve_a, pool.reserve_b);
        
        // 2. Validate amounts
        if amount_b < optimal_amount_b * 99 / 100 { // 1% slippage tolerance
            return Err(DeFiError::InsufficientAmountB);
        }
        
        // 3. Calculate liquidity
        let liquidity = if pool.total_liquidity == 0 {
            amount_a * amount_b // Initial liquidity
        } else {
            std::cmp::min(
                amount_a * pool.total_liquidity / pool.reserve_a,
                amount_b * pool.total_liquidity / pool.reserve_b,
            )
        };
        
        // 4. Update pool reserves
        pool.reserve_a += amount_a;
        pool.reserve_b += amount_b;
        pool.total_liquidity += liquidity;
        
        // 5. Mint LP tokens
        self.mint_lp_tokens(user, pool.lp_token, liquidity)?;
        
        Ok(liquidity)
    }
    
    pub fn swap(&mut self, user: [u8; 32], pool_address: [u8; 32], token_in: [u8; 32], amount_in: u128, amount_out_min: u128) -> Result<u128, DeFiError> {
        let pool = self.pools.get_mut(&pool_address)
            .ok_or(DeFiError::PoolNotFound)?;
        
        // 1. Determine swap direction
        let (reserve_in, reserve_out, token_out) = if token_in == pool.token_a {
            (&mut pool.reserve_a, &mut pool.reserve_b, pool.token_b)
        } else if token_in == pool.token_b {
            (&mut pool.reserve_b, &mut pool.reserve_a, pool.token_a)
        } else {
            return Err(DeFiError::InvalidToken);
        };
        
        // 2. Calculate amount out (with fees)
        let amount_in_with_fee = amount_in * (10000 - pool.fee_rate) / 10000;
        let amount_out = self.calculate_amount_out(amount_in_with_fee, *reserve_in, *reserve_out);
        
        // 3. Validate minimum amount out
        if amount_out < amount_out_min {
            return Err(DeFiError::InsufficientOutput);
        }
        
        // 4. Update reserves
        *reserve_in += amount_in;
        *reserve_out -= amount_out;
        
        // 5. Transfer tokens
        self.transfer_token_from(user, pool_address, token_in, amount_in)?;
        self.transfer_token_to(pool_address, user, token_out, amount_out)?;
        
        Ok(amount_out)
    }
    
    fn calculate_amount_out(&self, amount_in: u128, reserve_in: u128, reserve_out: u128) -> u128 {
        // Constant product formula: x * y = k
        // amount_out = (reserve_out * amount_in) / (reserve_in + amount_in)
        reserve_out * amount_in / (reserve_in + amount_in)
    }
    
    fn calculate_optimal_amount(&self, amount_a: u128, reserve_a: u128, reserve_b: u128) -> u128 {
        if reserve_a == 0 {
            return 0;
        }
        amount_a * reserve_b / reserve_a
    }
}

4. NFT Contract​

#[derive(Debug, Clone)]
pub struct NFTContract {
    pub base: BaseContract,                   // Base contract functionality
    pub tokens: HashMap<u64, NFT>,            // Tokens by ID
    pub ownership: HashMap<u64, [u8; 32]>,   // Token ownership
    pub balances: HashMap<[u8; 32], u64>,     // Owner balances
    pub approvals: HashMap<u64, [u8; 32]>,   // Token approvals
    pub operator_approvals: HashMap<([u8; 32], [u8; 32]), bool>, // Operator approvals
    pub token_count: u64,                     // Total token count
    pub minting_enabled: bool,                // Minting enabled
    pub royalty_info: HashMap<u64, RoyaltyInfo>, // Royalty information
}

#[derive(Debug, Clone)]
pub struct NFT {
    pub id: u64,                             // Token ID
    pub creator: [u8; 32],                   // Creator address
    pub metadata: NFTMetadata,                // Token metadata
    pub created_at: u64,                     // Creation timestamp
    pub transfer_count: u64,                  // Transfer count
}

#[derive(Debug, Clone)]
pub struct NFTMetadata {
    pub name: String,                        // Token name
    pub description: String,                  // Token description
    pub image_url: String,                    // Image URL
    pub attributes: Vec<NFTAttribute>,        // Token attributes
    pub external_url: Option<String>,         // External URL
}

#[derive(Debug, Clone)]
pub struct NFTAttribute {
    pub trait_type: String,                   // Trait type
    pub value: String,                        // Trait value
    pub display_type: Option<String>,         // Display type
}

#[derive(Debug, Clone)]
pub struct RoyaltyInfo {
    pub recipient: [u8; 32],                  // Royalty recipient
    pub percentage: u64,                      // Royalty percentage (basis points)
}

impl NFTContract {
    pub fn new(owner: [u8; 32]) -> Self {
        Self {
            base: BaseContract::new(owner),
            tokens: HashMap::new(),
            ownership: HashMap::new(),
            balances: HashMap::new(),
            approvals: HashMap::new(),
            operator_approvals: HashMap::new(),
            token_count: 0,
            minting_enabled: true,
            royalty_info: HashMap::new(),
        }
    }
    
    pub fn mint(&mut self, to: [u8; 32], metadata: NFTMetadata, royalty: Option<RoyaltyInfo>) -> Result<u64, NFTError> {
        if !self.minting_enabled {
            return Err(NFTError::MintingDisabled);
        }
        
        let token_id = self.token_count;
        let current_time = current_timestamp();
        
        let nft = NFT {
            id: token_id,
            creator: to,
            metadata,
            created_at: current_time,
            transfer_count: 0,
        };
        
        // Store token
        self.tokens.insert(token_id, nft);
        self.ownership.insert(token_id, to);
        *self.balances.entry(to).or_insert(0) += 1;
        
        // Store royalty info if provided
        if let Some(royalty) = royalty {
            self.royalty_info.insert(token_id, royalty);
        }
        
        self.token_count += 1;
        
        Ok(token_id)
    }
    
    pub fn transfer(&mut self, from: [u8; 32], to: [u8; 32], token_id: u64) -> Result<(), NFTError> {
        // 1. Validate ownership
        let owner = self.ownership.get(&token_id)
            .ok_or(NFTError::TokenNotFound)?;
        
        if *owner != from {
            return Err(NFTError::NotOwner);
        }
        
        // 2. Check approval
        let approved = self.approvals.get(&token_id);
        if approved.is_some() && approved.unwrap() != to {
            // Check operator approval
            let operator_approved = self.operator_approvals.get(&(from, to)).unwrap_or(&false);
            if !operator_approved {
                return Err(NFTError::NotApproved);
            }
        }
        
        // 3. Update ownership
        self.ownership.insert(token_id, to);
        *self.balances.entry(from).or_insert(0) -= 1;
        *self.balances.entry(to).or_insert(0) += 1;
        
        // 4. Clear approval
        self.approvals.remove(&token_id);
        
        // 5. Update transfer count
        if let Some(nft) = self.tokens.get_mut(&token_id) {
            nft.transfer_count += 1;
        }
        
        Ok(())
    }
    
    pub fn approve(&mut self, owner: [u8; 32], approved: [u8; 32], token_id: u64) -> Result<(), NFTError> {
        // 1. Validate ownership
        let token_owner = self.ownership.get(&token_id)
            .ok_or(NFTError::TokenNotFound)?;
        
        if *token_owner != owner {
            return Err(NFTError::NotOwner);
        }
        
        // 2. Set approval
        self.approvals.insert(token_id, approved);
        
        Ok(())
    }
    
    pub fn set_approval_for_all(&mut self, owner: [u8; 32], operator: [u8; 32], approved: bool) -> Result<(), NFTError> {
        self.operator_approvals.insert((owner, operator), approved);
        Ok(())
    }
    
    pub fn get_royalty(&self, token_id: u64, sale_price: u128) -> Option<( [u8; 32], u128)> {
        let royalty = self.royalty_info.get(&token_id)?;
        let royalty_amount = sale_price * royalty.percentage as u128 / 10000;
        Some((royalty.recipient, royalty_amount))
    }
}

Contract Execution Environment​

Runtime Environment​

pub struct ContractRuntime {
    pub contracts: HashMap<[u8; 32], ContractInstance>, // Contract instances
    pub storage: ContractStorage,              // Contract storage
    pub gas_meter: GasMeter,                    // Gas metering
    pub call_stack: Vec<CallFrame>,             // Call stack
    pub event_emitter: EventEmitter,            // Event emission
    pub access_control: AccessController,       // Access control
}

#[derive(Debug, Clone)]
pub struct ContractInstance {
    pub bytecode: Vec<u8>,                    // Contract bytecode
    pub storage: HashMap<u64, Vec<u8>>,        // Contract storage
    pub balance: u128,                         // Contract balance
    pub owner: [u8; 32],                       // Contract owner
    pub version: u64,                          // Contract version
    pub paused: bool,                          // Pause state
    pub upgrade_enabled: bool,                 // Upgrade enabled
}

#[derive(Debug, Clone)]
pub struct CallFrame {
    pub contract: [u8; 32],                    // Contract address
    pub caller: [u8; 32],                      // Caller address
    pub value: u128,                           // Call value
    pub data: Vec<u8>,                         // Call data
    pub gas_limit: u64,                        // Gas limit
    pub gas_used: u64,                         // Gas used
    pub return_data: Vec<u8>,                  // Return data
    pub success: bool,                          // Call success
}

impl ContractRuntime {
    pub fn execute_contract(&mut self, contract_address: [u8; 32], caller: [u8; 32], value: u128, data: Vec<u8], gas_limit: u64) -> Result<Vec<u8>, ExecutionError> {
        // 1. Validate contract exists
        let contract = self.contracts.get_mut(&contract_address)
            .ok_or(ExecutionError::ContractNotFound)?;
        
        // 2. Check if contract is paused
        if contract.paused {
            return Err(ExecutionError::ContractPaused);
        }
        
        // 3. Create call frame
        let call_frame = CallFrame {
            contract: contract_address,
            caller,
            value,
            data: data.clone(),
            gas_limit,
            gas_used: 0,
            return_data: Vec::new(),
            success: false,
        };
        
        // 4. Push to call stack
        self.call_stack.push(call_frame);
        
        // 5. Execute contract
        let result = self.execute_bytecode(contract, &data, gas_limit);
        
        // 6. Pop call stack
        let mut call_frame = self.call_stack.pop().unwrap();
        call_frame.success = result.is_ok();
        
        if let Ok(ref return_data) = result {
            call_frame.return_data = return_data.clone();
        }
        
        // 7. Update gas usage
        contract.storage.insert(0, call_frame.gas_used.to_le_bytes().to_vec());
        
        result
    }
    
    fn execute_bytecode(&mut self, contract: &mut ContractInstance, data: &[u8], gas_limit: u64) -> Result<Vec<u8>, ExecutionError> {
        let mut pc = 0;
        let mut gas_used = 0;
        let mut stack = Vec::new();
        let mut memory = Vec::new();
        
        while pc < contract.bytecode.len() && gas_used < gas_limit {
            let opcode = contract.bytecode[pc];
            
            match opcode {
                0x01 => { // ADD
                    if stack.len() < 2 {
                        return Err(ExecutionError::StackUnderflow);
                    }
                    let a = stack.pop().unwrap();
                    let b = stack.pop().unwrap();
                    stack.push(a + b);
                    gas_used += 3;
                },
                0x02 => { // MUL
                    if stack.len() < 2 {
                        return Err(ExecutionError::StackUnderflow);
                    }
                    let a = stack.pop().unwrap();
                    let b = stack.pop().unwrap();
                    stack.push(a * b);
                    gas_used += 5;
                },
                0x03 => { // SUB
                    if stack.len() < 2 {
                        return Err(ExecutionError::StackUnderflow);
                    }
                    let a = stack.pop().unwrap();
                    let b = stack.pop().unwrap();
                    stack.push(a - b);
                    gas_used += 3;
                },
                0x04 => { // DIV
                    if stack.len() < 2 {
                        return Err(ExecutionError::StackUnderflow);
                    }
                    let a = stack.pop().unwrap();
                    let b = stack.pop().unwrap();
                    if b == 0 {
                        return Err(ExecutionError::DivisionByZero);
                    }
                    stack.push(a / b);
                    gas_used += 5;
                },
                0x10 => { // CALL
                    if stack.len() < 4 {
                        return Err(ExecutionError::StackUnderflow);
                    }
                    let gas = stack.pop().unwrap();
                    let addr_bytes = stack.pop().unwrap();
                    let value = stack.pop().unwrap();
                    let args_offset = stack.pop().unwrap();
                    
                    let mut addr = [0u8; 32];
                    addr.copy_from_slice(&addr_bytes.to_le_bytes());
                    
                    let call_data = self.extract_call_data(&memory, args_offset);
                    let result = self.execute_contract(addr, contract_address, value, call_data, gas);
                    
                    stack.push(if result.is_ok() { 1 } else { 0 });
                    gas_used += 40;
                },
                0x20 => { // SLOAD
                    if stack.len() < 1 {
                        return Err(ExecutionError::StackUnderflow);
                    }
                    let key = stack.pop().unwrap();
                    let value = contract.storage.get(&key).cloned().unwrap_or_default();
                    stack.push(u128::from_le_bytes([
                        value.get(0).copied().unwrap_or(0),
                        value.get(1).copied().unwrap_or(0),
                        value.get(2).copied().unwrap_or(0),
                        value.get(3).copied().unwrap_or(0),
                        value.get(4).copied().unwrap_or(0),
                        value.get(5).copied().unwrap_or(0),
                        value.get(6).copied().unwrap_or(0),
                        value.get(7).copied().unwrap_or(0),
                        value.get(8).copied().unwrap_or(0),
                        value.get(9).copied().unwrap_or(0),
                        value.get(10).copied().unwrap_or(0),
                        value.get(11).copied().unwrap_or(0),
                        value.get(12).copied().unwrap_or(0),
                        value.get(13).copied().unwrap_or(0),
                        value.get(14).copied().unwrap_or(0),
                        value.get(15).copied().unwrap_or(0),
                    ]));
                    gas_used += 200;
                },
                0x21 => { // SSTORE
                    if stack.len() < 2 {
                        return Err(ExecutionError::StackUnderflow);
                    }
                    let key = stack.pop().unwrap();
                    let value = stack.pop().unwrap();
                    contract.storage.insert(key, value.to_le_bytes().to_vec());
                    gas_used += 5000;
                },
                0x30 => { // RETURN
                    if stack.len() < 2 {
                        return Err(ExecutionError::StackUnderflow);
                    }
                    let offset = stack.pop().unwrap();
                    let size = stack.pop().unwrap();
                    let return_data = self.extract_memory_data(&memory, offset, size);
                    return Ok(return_data);
                },
                0x31 => { // REVERT
                    if stack.len() < 2 {
                        return Err(ExecutionError::StackUnderflow);
                    }
                    let offset = stack.pop().unwrap();
                    let size = stack.pop().unwrap();
                    let revert_data = self.extract_memory_data(&memory, offset, size);
                    return Err(ExecutionError::Revert(revert_data));
                },
                _ => {
                    return Err(ExecutionError::InvalidOpcode(opcode));
                }
            }
            
            pc += 1;
        }
        
        if gas_used >= gas_limit {
            return Err(ExecutionError::OutOfGas);
        }
        
        Ok(Vec::new())
    }
}

This smart contract types specification provides a comprehensive foundation for enterprise-grade blockchain applications with advanced features, security mechanisms, and performance optimizations.