xdr/Stellar-ledger.x in stellar-base-0.0.18 vs xdr/Stellar-ledger.x in stellar-base-0.0.19

@@ -5,37 +5,91 @@
 %#include "generated/Stellar-transaction.h"
 
 namespace stellar
 {
 
+typedef opaque UpgradeType<128>;
+
+/* StellarValue is the value used by SCP to reach consensus on a given ledger
+*/
+struct StellarValue
+{
+    Hash txSetHash;   // transaction set to apply to previous ledger
+    uint64 closeTime; // network close time
+
+    // upgrades to apply to the previous ledger (usually empty)
+    // this is a vector of encoded 'LedgerUpgrade' so that nodes can drop
+    // unknown steps during consensus if needed.
+    // see notes below on 'LedgerUpgrade' for more detail
+    UpgradeType upgrades<4>;
+
+    // reserved for future use
+    union switch (int v)
+    {
+    case 0:
+        void;
+    }
+    ext;
+};
+
 /* The LedgerHeader is the highest level structure representing the
  * state of a ledger, cryptographically linked to previous ledgers.
 */
 struct LedgerHeader
 {
+    uint32 ledgerVersion;    // the protocol version of the ledger
     Hash previousLedgerHash; // hash of the previous ledger header
-    Hash txSetHash;          // the tx set that was SCP confirmed
+    StellarValue scpValue;   // what consensus agreed to
     Hash txSetResultHash;    // the TransactionResultSet that led to this ledger
     Hash bucketListHash;     // hash of the ledger state
 
     uint32 ledgerSeq; // sequence number of this ledger
-    uint64 closeTime; // network close time
 
     int64 totalCoins; // total number of stroops in existence
 
     int64 feePool;       // fees burned since last inflation run
     uint32 inflationSeq; // inflation sequence number
 
     uint64 idPool; // last used global ID, used for generating objects
 
-    int32 baseFee;     // base fee per operation in stroops
-    int32 baseReserve; // account base reserve in stroops
+    uint32 baseFee;     // base fee per operation in stroops
+    uint32 baseReserve; // account base reserve in stroops
 
-    Hash skipList[4];  // hashes of ledgers in the past. allows you to jump back
-                       // in time without walking the chain back ledger by ledger
+    Hash skipList[4]; // hashes of ledgers in the past. allows you to jump back
+                      // in time without walking the chain back ledger by ledger
+                      // each slot contains the oldest ledger that is mod of
+                      // either 50  5000  50000 or 500000 depending on index
+                      // skipList[0] mod(50), skipList[1] mod(5000), etc
+
+    // reserved for future use
+    union switch (int v)
+    {
+    case 0:
+        void;
+    }
+    ext;
 };
 
+/* Ledger upgrades
+note that the `upgrades` field from StellarValue is normalized such that
+it only contains one entry per LedgerUpgradeType, and entries are sorted
+in ascending order
+*/
+enum LedgerUpgradeType
+{
+    LEDGER_UPGRADE_VERSION = 1,
+    LEDGER_UPGRADE_BASE_FEE = 2
+};
+
+union LedgerUpgrade switch (LedgerUpgradeType type)
+{
+case LEDGER_UPGRADE_VERSION:
+    uint32 newLedgerVersion; // update ledgerVersion
+case LEDGER_UPGRADE_BASE_FEE:
+    uint32 newBaseFee; // update baseFee
+};
+
 /* Entries used to define the bucket list */
 
 union LedgerKey switch (LedgerEntryType type)
 {
 case ACCOUNT:
@@ -74,14 +128,15 @@
     LedgerKey deadEntry;
 };
 
 // Transaction sets are the unit used by SCP to decide on transitions
 // between ledgers
+const MAX_TX_PER_LEDGER = 5000;
 struct TransactionSet
 {
     Hash previousLedgerHash;
-    TransactionEnvelope txs<5000>;
+    TransactionEnvelope txs<MAX_TX_PER_LEDGER>;
 };
 
 struct TransactionResultPair
 {
     Hash transactionHash;
@@ -89,30 +144,54 @@
 };
 
 // TransactionResultSet is used to recover results between ledgers
 struct TransactionResultSet
 {
-    TransactionResultPair results<5000>;
+    TransactionResultPair results<MAX_TX_PER_LEDGER>;
 };
 
 // Entries below are used in the historical subsystem
 
 struct TransactionHistoryEntry
 {
     uint32 ledgerSeq;
     TransactionSet txSet;
+
+    // reserved for future use
+    union switch (int v)
+    {
+    case 0:
+        void;
+    }
+    ext;
 };
 
 struct TransactionHistoryResultEntry
 {
     uint32 ledgerSeq;
     TransactionResultSet txResultSet;
+
+    // reserved for future use
+    union switch (int v)
+    {
+    case 0:
+        void;
+    }
+    ext;
 };
 
 struct LedgerHeaderHistoryEntry
 {
     Hash hash;
     LedgerHeader header;
+
+    // reserved for future use
+    union switch (int v)
+    {
+    case 0:
+        void;
+    }
+    ext;
 };
 
 // represents the meta in the transaction table history
 
 enum LedgerEntryChangeType