Archival proofs (#204) (#205)

* Added Archival proof types

* Moved Bucket types to remove circular dependency

Stellar-ledger-entries.x

@@ -679,3 +679,119 @@ enum EnvelopeType
     ENVELOPE_TYPE_SOROBAN_AUTHORIZATION = 9
 };
 }
+
+enum BucketListType
+{
+    LIVE = 0,
+    HOT_ARCHIVE = 1,
+    COLD_ARCHIVE = 2
+};
+
+/* Entries used to define the bucket list */
+enum BucketEntryType
+{
+    METAENTRY =
+        -1, // At-and-after protocol 11: bucket metadata, should come first.
+    LIVEENTRY = 0, // Before protocol 11: created-or-updated;
+                   // At-and-after protocol 11: only updated.
+    DEADENTRY = 1,
+    INITENTRY = 2 // At-and-after protocol 11: only created.
+};
+
+enum HotArchiveBucketEntryType
+{
+    HOT_ARCHIVE_METAENTRY = -1, // Bucket metadata, should come first.
+    HOT_ARCHIVE_ARCHIVED = 0,   // Entry is Archived
+    HOT_ARCHIVE_LIVE = 1,       // Entry was previously HOT_ARCHIVE_ARCHIVED, or HOT_ARCHIVE_DELETED, but
+                                // has been added back to the live BucketList.
+                                // Does not need to be persisted.
+    HOT_ARCHIVE_DELETED = 2     // Entry deleted (Note: must be persisted in archive)
+};
+
+enum ColdArchiveBucketEntryType
+{
+    COLD_ARCHIVE_METAENTRY     = -1,  // Bucket metadata, should come first.
+    COLD_ARCHIVE_ARCHIVED_LEAF = 0,   // Full LedgerEntry that was archived during the epoch
+    COLD_ARCHIVE_DELETED_LEAF  = 1,   // LedgerKey that was deleted during the epoch
+    COLD_ARCHIVE_BOUNDARY_LEAF = 2,   // Dummy leaf representing low/high bound
+    COLD_ARCHIVE_HASH          = 3    // Intermediary Merkle hash entry
+};
+
+struct BucketMetadata
+{
+    // Indicates the protocol version used to create / merge this bucket.
+    uint32 ledgerVersion;
+
+    // reserved for future use
+    union switch (int v)
+    {
+    case 0:
+        void;
+    case 1:
+        BucketListType bucketListType;
+    }
+    ext;
+};
+
+union BucketEntry switch (BucketEntryType type)
+{
+case LIVEENTRY:
+case INITENTRY:
+    LedgerEntry liveEntry;
+
+case DEADENTRY:
+    LedgerKey deadEntry;
+case METAENTRY:
+    BucketMetadata metaEntry;
+};
+
+union HotArchiveBucketEntry switch (HotArchiveBucketEntryType type)
+{
+case HOT_ARCHIVE_ARCHIVED:
+    LedgerEntry archivedEntry;
+
+case HOT_ARCHIVE_LIVE:
+case HOT_ARCHIVE_DELETED:
+    LedgerKey key;
+case HOT_ARCHIVE_METAENTRY:
+    BucketMetadata metaEntry;
+};
+
+struct ColdArchiveArchivedLeaf
+{
+    uint32 index;
+    LedgerEntry archivedEntry;
+};
+
+struct ColdArchiveDeletedLeaf
+{
+    uint32 index;
+    LedgerKey deletedKey;
+};
+
+struct ColdArchiveBoundaryLeaf
+{
+    uint32 index;
+    bool isLowerBound;
+};
+
+struct ColdArchiveHashEntry
+{
+    uint32 index;
+    uint32 level;
+    Hash hash;
+};
+
+union ColdArchiveBucketEntry switch (ColdArchiveBucketEntryType type)
+{
+case COLD_ARCHIVE_METAENTRY:
+    BucketMetadata metaEntry;
+case COLD_ARCHIVE_ARCHIVED_LEAF:
+    ColdArchiveArchivedLeaf archivedLeaf;
+case COLD_ARCHIVE_DELETED_LEAF:
+    ColdArchiveDeletedLeaf deletedLeaf;
+case COLD_ARCHIVE_BOUNDARY_LEAF:
+    ColdArchiveBoundaryLeaf boundaryLeaf;
+case COLD_ARCHIVE_HASH:
+    ColdArchiveHashEntry hashEntry;
+};

Stellar-ledger.x

@@ -157,74 +157,6 @@ struct ConfigUpgradeSet {
     ConfigSettingEntry updatedEntry<>;
 };
 
-enum BucketListType
-{
-    LIVE = 0,
-    HOT_ARCHIVE = 1,
-    COLD_ARCHIVE = 2
-};
-
-/* Entries used to define the bucket list */
-enum BucketEntryType
-{
-    METAENTRY =
-        -1, // At-and-after protocol 11: bucket metadata, should come first.
-    LIVEENTRY = 0, // Before protocol 11: created-or-updated;
-                   // At-and-after protocol 11: only updated.
-    DEADENTRY = 1,
-    INITENTRY = 2 // At-and-after protocol 11: only created.
-};
-
-enum HotArchiveBucketEntryType
-{
-    HOT_ARCHIVE_METAENTRY = -1, // Bucket metadata, should come first.
-    HOT_ARCHIVE_ARCHIVED = 0,   // Entry is Archived
-    HOT_ARCHIVE_LIVE = 1,       // Entry was previously HOT_ARCHIVE_ARCHIVED, or HOT_ARCHIVE_DELETED, but
-                                // has been added back to the live BucketList.
-                                // Does not need to be persisted.
-    HOT_ARCHIVE_DELETED = 2     // Entry deleted (Note: must be persisted in archive)
-};
-
-struct BucketMetadata
-{
-    // Indicates the protocol version used to create / merge this bucket.
-    uint32 ledgerVersion;
-
-    // reserved for future use
-    union switch (int v)
-    {
-    case 0:
-        void;
-    case 1:
-        BucketListType bucketListType;
-    }
-    ext;
-};
-
-union BucketEntry switch (BucketEntryType type)
-{
-case LIVEENTRY:
-case INITENTRY:
-    LedgerEntry liveEntry;
-
-case DEADENTRY:
-    LedgerKey deadEntry;
-case METAENTRY:
-    BucketMetadata metaEntry;
-};
-
-union HotArchiveBucketEntry switch (HotArchiveBucketEntryType type)
-{
-case HOT_ARCHIVE_ARCHIVED:
-    LedgerEntry archivedEntry;
-
-case HOT_ARCHIVE_LIVE:
-case HOT_ARCHIVE_DELETED:
-    LedgerKey key;
-case HOT_ARCHIVE_METAENTRY:
-    BucketMetadata metaEntry;
-};
-
 enum TxSetComponentType
 {
   // txs with effective fee <= bid derived from a base fee (if any).

Stellar-transaction.x

@@ -819,6 +819,52 @@ struct LedgerFootprint
     LedgerKey readWrite<>;
 };
 
+enum ArchivalProofType
+{
+    EXISTENCE = 0,
+    NONEXISTENCE = 1
+};
+
+struct ArchivalProofNode
+{
+    uint32 index;
+    Hash hash;
+};
+
+typedef ArchivalProofNode ProofLevel<>;
+
+struct ArchivalProof
+{
+    uint32 epoch; // AST Subtree for this proof
+
+    union switch (ArchivalProofType t)
+    {
+    case EXISTENCE:
+        struct
+        {
+            ColdArchiveBucketEntry entriesToProve<>;
+
+            // Vector of vectors, where proofLevels[level]
+            // contains all HashNodes that correspond with that level
+            ProofLevel proofLevels<>;
+        } existenceProof;
+    case NONEXISTENCE:
+        struct
+        {
+            LedgerKey keysToProve<>;
+
+            // Bounds for each key being proved, where bound[n]
+            // corresponds to keysToProve[n]
+            ColdArchiveBucketEntry lowBoundEntries<>;
+            ColdArchiveBucketEntry highBoundEntries<>;
+
+            // Vector of vectors, where proofLevels[level]
+            // contains all HashNodes that correspond with that level
+            ProofLevel proofLevels<>;
+        } nonexistenceProof;
+    } type;
+};
+
 // Resource limits for a Soroban transaction.
 // The transaction will fail if it exceeds any of these limits.
 struct SorobanResources
@@ -837,7 +883,13 @@ struct SorobanResources
 // The transaction extension for Soroban.
 struct SorobanTransactionData
 {
-    ExtensionPoint ext;
+    union switch (int v)
+    {
+    case 0:
+        void;
+    case 1:
+        ArchivalProof proofs<>;
+    } ext;
     SorobanResources resources;
     // Amount of the transaction `fee` allocated to the Soroban resource fees.
     // The fraction of `resourceFee` corresponding to `resources` specified