populate

Stellar-SCP.x

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+// Copyright 2015 Stellar Development Foundation and contributors. Licensed
+// under the Apache License, Version 2.0. See the COPYING file at the root
+// of this distribution or at http://www.apache.org/licenses/LICENSE-2.0
+
+%#include "xdr/Stellar-types.h"
+
+namespace stellar
+{
+
+typedef opaque Value<>;
+
+struct SCPBallot
+{
+    uint32 counter; // n
+    Value value;    // x
+};
+
+enum SCPStatementType
+{
+    SCP_ST_PREPARE = 0,
+    SCP_ST_CONFIRM = 1,
+    SCP_ST_EXTERNALIZE = 2,
+    SCP_ST_NOMINATE = 3
+};
+
+struct SCPNomination
+{
+    Hash quorumSetHash; // D
+    Value votes<>;      // X
+    Value accepted<>;   // Y
+};
+
+struct SCPStatement
+{
+    NodeID nodeID;    // v
+    uint64 slotIndex; // i
+
+    union switch (SCPStatementType type)
+    {
+    case SCP_ST_PREPARE:
+        struct
+        {
+            Hash quorumSetHash;       // D
+            SCPBallot ballot;         // b
+            SCPBallot* prepared;      // p
+            SCPBallot* preparedPrime; // p'
+            uint32 nC;                // c.n
+            uint32 nH;                // h.n
+        } prepare;
+    case SCP_ST_CONFIRM:
+        struct
+        {
+            SCPBallot ballot;   // b
+            uint32 nPrepared;   // p.n
+            uint32 nCommit;     // c.n
+            uint32 nH;          // h.n
+            Hash quorumSetHash; // D
+        } confirm;
+    case SCP_ST_EXTERNALIZE:
+        struct
+        {
+            SCPBallot commit;         // c
+            uint32 nH;                // h.n
+            Hash commitQuorumSetHash; // D used before EXTERNALIZE
+        } externalize;
+    case SCP_ST_NOMINATE:
+        SCPNomination nominate;
+    }
+    pledges;
+};
+
+struct SCPEnvelope
+{
+    SCPStatement statement;
+    Signature signature;
+};
+
+// supports things like: A,B,C,(D,E,F),(G,H,(I,J,K,L))
+// only allows 2 levels of nesting
+struct SCPQuorumSet
+{
+    uint32 threshold;
+    NodeID validators<>;
+    SCPQuorumSet innerSets<>;
+};
+}

Stellar-contract.x

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+// Copyright 2022 Stellar Development Foundation and contributors. Licensed
+// under the Apache License, Version 2.0. See the COPYING file at the root
+// of this distribution or at http://www.apache.org/licenses/LICENSE-2.0
+
+% #include "xdr/Stellar-types.h"
+namespace stellar
+{
+/*
+ * Smart Contracts deal in SCVals. These are a (dynamic) disjoint union
+ * between several possible variants, to allow storing generic SCVals in
+ * generic data structures and passing them in and out of languages that
+ * have simple or dynamic type systems.
+ *
+ * SCVals are (in WASM's case) stored in a tagged 64-bit word encoding. Most
+ * signed 64-bit values in Stellar are actually signed positive values
+ * (sequence numbers, timestamps, amounts), so we don't need the high bit
+ * and can get away with 1-bit tagging and store them as "unsigned 63bit",
+ * (u63) separate from everything else.
+ *
+ * We actually reserve the low _four_ bits, leaving 3 bits for 8 cases of
+ * "non-u63 values", some of which have substructure of their own.
+ *
+ *    0x_NNNN_NNNN_NNNN_NNNX  - u63, for any even X
+ *    0x_0000_000N_NNNN_NNN1  - u32
+ *    0x_0000_000N_NNNN_NNN3  - i32
+ *    0x_NNNN_NNNN_NNNN_NNN5  - static: void, true, false, ... (SCS_*)
+ *    0x_IIII_IIII_TTTT_TTT7  - object: 32-bit index I, 28-bit type code T
+ *    0x_NNNN_NNNN_NNNN_NNN9  - symbol: up to 10 6-bit identifier characters
+ *    0x_NNNN_NNNN_NNNN_NNNb  - bitset: up to 60 bits
+ *    0x_CCCC_CCCC_TTTT_TTTd  - status: 32-bit code C, 28-bit type code T
+ *    0x_NNNN_NNNN_NNNN_NNNf  - reserved
+ *
+ * Up here in XDR we have variable-length tagged disjoint unions but no
+ * bit-level packing, so we can be more explicit in their structure, at the
+ * cost of spending more than 64 bits to encode many cases, and also having
+ * to convert. It's a little non-obvious at the XDR level why there's a
+ * split between SCVal and SCObject given that they are both immutable types
+ * with value semantics; but the split reflects the split that happens in
+ * the implementation, and marks a place where different implementations of
+ * immutability (CoW, structural sharing, etc.) will likely occur.
+ */
+
+// A symbol is up to 10 chars drawn from [a-zA-Z0-9_], which can be packed
+// into 60 bits with a 6-bit-per-character code, usable as a small key type
+// to specify function, argument, tx-local environment and map entries
+// efficiently.
+typedef string SCSymbol<10>;
+
+enum SCValType
+{
+    SCV_U63 = 0,
+    SCV_U32 = 1,
+    SCV_I32 = 2,
+    SCV_STATIC = 3,
+    SCV_OBJECT = 4,
+    SCV_SYMBOL = 5,
+    SCV_BITSET = 6,
+    SCV_STATUS = 7
+};
+
+% struct SCObject;
+
+enum SCStatic
+{
+    SCS_VOID = 0,
+    SCS_TRUE = 1,
+    SCS_FALSE = 2,
+    SCS_LEDGER_KEY_CONTRACT_CODE_WASM = 3
+};
+
+enum SCStatusType
+{
+    SST_OK = 0,
+    SST_UNKNOWN_ERROR = 1
+    // TODO: add more
+};
+
+union SCStatus switch (SCStatusType type)
+{
+case SST_OK:
+    void;
+case SST_UNKNOWN_ERROR:
+    uint32 unknownCode;
+};
+
+union SCVal switch (SCValType type)
+{
+case SCV_U63:
+    int64 u63;
+case SCV_U32:
+    uint32 u32;
+case SCV_I32:
+    int32 i32;
+case SCV_STATIC:
+    SCStatic ic;
+case SCV_OBJECT:
+    SCObject* obj;
+case SCV_SYMBOL:
+    SCSymbol sym;
+case SCV_BITSET:
+    uint64 bits;
+case SCV_STATUS:
+    SCStatus status;
+};
+
+enum SCObjectType
+{
+    // We have a few objects that represent non-stellar-specific concepts
+    // like general-purpose maps, vectors, numbers, blobs.
+
+    SCO_VEC = 0,
+    SCO_MAP = 1,
+    SCO_U64 = 2,
+    SCO_I64 = 3,
+    SCO_BINARY = 4
+
+    // TODO: add more
+};
+
+struct SCMapEntry
+{
+    SCVal key;
+    SCVal val;
+};
+
+const SCVAL_LIMIT = 256000;
+
+typedef SCVal SCVec<SCVAL_LIMIT>;
+typedef SCMapEntry SCMap<SCVAL_LIMIT>;
+
+union SCObject switch (SCObjectType type)
+{
+case SCO_VEC:
+    SCVec vec;
+case SCO_MAP:
+    SCMap map;
+case SCO_U64:
+    uint64 u64;
+case SCO_I64:
+    int64 i64;
+case SCO_BINARY:
+    opaque bin<SCVAL_LIMIT>;
+};
+}