feat: Implement investor participant counter and maximum investor cap (#105)

soroban-contracts/contracts/single_rwa_vault/src/errors.rs

@@ -56,6 +56,12 @@ pub enum Error {
     /// Burn requires pending yield to be claimed first (Option A).
     BurnRequiresYieldClaim = 32,
     InvalidDepositLimits = 33,
+    /// Shares are still within lock-up period and cannot be transferred
+    SharesLocked = 34,
+    /// Vault has insufficient balance to cover the requested transfer
+    InsufficientVaultBalance = 35,
+    /// Maximum number of investors has been reached
+    MaxInvestorsReached = 36,
     /// Timelock action not found or invalid.
     TimelockActionNotFound = 34,
     /// Timelock delay has not passed yet.

soroban-contracts/contracts/single_rwa_vault/src/storage.rs

@@ -59,13 +59,13 @@ pub enum Key {
     ExpApy,
 
     // --- Vault config ---
-    FundTgt,
-    MatDate,
-    MinDep,
-    MaxDepUsr,
-    ERedFee,
-    /// Yield vesting period in seconds (0 = instant claiming for backward compatibility)
-    YldVstPer,
+    FundingTarget,
+    MaturityDate,
+    MinDeposit,
+    MaxDepositPerUser,
+    MaxInvestors,
+    EarlyRedemptionFeeBps,
+    LockUpPeriod,
 
     // --- Vault state ---
     VaultSt,
@@ -106,11 +106,15 @@ pub enum Key {
     TotSup,
 
     // --- User deposit tracking ---
-    UsrDep(Address),
+    UserDeposited(Address),
+    DepositTimestamp(Address),
 
     // --- Total deposited principal ---
     TotDep,
 
+    // --- Investor tracking ---
+    InvestorCount,
+
     // --- Early redemption ---
     RedCnt,
     RedReq(u32),
@@ -469,18 +473,23 @@ pub fn put_funding_deadline(e: &Env, val: u64) {
     e.storage().instance().set(&Key::FundDeadl, &val);
 }
 
-instance_get!(get_min_deposit, MinDep, i128);
-instance_put!(put_min_deposit, MinDep, i128);
-instance_get!(get_max_deposit_per_user, MaxDepUsr, i128);
-instance_put!(put_max_deposit_per_user, MaxDepUsr, i128);
-instance_get!(get_early_redemption_fee_bps, ERedFee, u32);
-instance_put!(put_early_redemption_fee_bps, ERedFee, u32);
+instance_get!(get_min_deposit, MinDeposit, i128);
+instance_put!(put_min_deposit, MinDeposit, i128);
+instance_get!(get_max_deposit_per_user, MaxDepositPerUser, i128);
+instance_put!(put_max_deposit_per_user, MaxDepositPerUser, i128);
+instance_get!(get_max_investors, MaxInvestors, u32);
+instance_put!(put_max_investors, MaxInvestors, u32);
+instance_get!(get_early_redemption_fee_bps, EarlyRedemptionFeeBps, u32);
+instance_put!(put_early_redemption_fee_bps, EarlyRedemptionFeeBps, u32);
 
-pub fn get_yield_vesting_period(e: &Env) -> u64 {
-    e.storage().instance().get(&Key::YldVstPer).unwrap_or(0) // Default to 0 for backward compatibility (instant claiming)
+pub fn get_lock_up_period(e: &Env) -> u64 {
+    e.storage()
+        .instance()
+        .get(&DataKey::LockUpPeriod)
+        .unwrap_or(0)
 }
-pub fn put_yield_vesting_period(e: &Env, val: u64) {
-    e.storage().instance().set(&Key::YldVstPer, &val);
+pub fn put_lock_up_period(e: &Env, val: u64) {
+    e.storage().instance().set(&DataKey::LockUpPeriod, &val);
 }
 
 // State
@@ -514,6 +523,10 @@ instance_put!(put_total_supply, TotSup, i128);
 instance_get!(get_total_deposited, TotDep, i128);
 instance_put!(put_total_deposited, TotDep, i128);
 
+// InvestorCount (unique investor tracking)
+instance_get!(get_investor_count, InvestorCount, u32);
+instance_put!(put_investor_count, InvestorCount, u32);
+
 // RedemptionCounter
 instance_get!(get_redemption_counter, RedCnt, u32);
 instance_put!(put_redemption_counter, RedCnt, u32);
@@ -723,6 +736,23 @@ pub fn put_user_deposited(e: &Env, addr: &Address, val: i128) {
     );
 }
 
+pub fn get_deposit_timestamp(e: &Env, addr: &Address) -> u64 {
+    e.storage()
+        .persistent()
+        .get(&DataKey::DepositTimestamp(addr.clone()))
+        .unwrap_or(0)
+}
+pub fn put_deposit_timestamp(e: &Env, addr: &Address, val: u64) {
+    e.storage()
+        .persistent()
+        .set(&DataKey::DepositTimestamp(addr.clone()), &val);
+    e.storage().persistent().extend_ttl(
+        &DataKey::DepositTimestamp(addr.clone()),
+        BALANCE_LIFETIME_THRESHOLD,
+        BALANCE_BUMP_AMOUNT,
+    );
+}
+
 pub fn get_total_yield_claimed(e: &Env, addr: &Address) -> i128 {
     e.storage()
         .persistent()

soroban-contracts/contracts/single_rwa_vault/src/test_constructor_validation.rs

@@ -22,14 +22,14 @@ fn get_valid_params(e: &Env) -> InitParams {
         funding_deadline: 0,
         min_deposit: 10,
         max_deposit_per_user: 100,
+        max_investors: 100,
         early_redemption_fee_bps: 200,
         rwa_name: String::from_str(e, "RWA"),
         rwa_symbol: String::from_str(e, "R"),
         rwa_document_uri: String::from_str(e, "uri"),
         rwa_category: String::from_str(e, "cat"),
         expected_apy: 500,
-        timelock_delay: 172800u64, // 48 hours
-        yield_vesting_period: 0u64,
+        lock_up_period: 0u64,
     }
 }
 

soroban-contracts/contracts/single_rwa_vault/src/test_helpers.rs

@@ -264,13 +264,13 @@ fn default_params(
         funding_deadline: 9_999_999_999u64, // far future (no effective deadline by default)
         min_deposit: 1_000_000i128,         // 1 USDC
         max_deposit_per_user: 0i128,        // unlimited
+        max_investors: 100u32,              // reasonable default for tests
         early_redemption_fee_bps: 200u32,   // 2 %
         rwa_name: String::from_str(env, "US Treasury Bond 2026"),
         rwa_symbol: String::from_str(env, "USTB26"),
         rwa_document_uri: String::from_str(env, "https://example.com/ustb26"),
         rwa_category: String::from_str(env, "Government Bond"),
-        expected_apy: 500u32,       // 5 %
-        timelock_delay: 172800u64,  // 48 hours
-        yield_vesting_period: 0u64, // Default to 0 for instant claiming (backward compatibility)
+        expected_apy: 500u32, // 5 %
+        lock_up_period: 0u64, // no lock-up by default
     }
 }