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zeekay
4dfb24878c
Adds SOLAssembler — companion to the EVM Assembler — that constructs
Solana transactions for the bridge's destination-release flow:
- PreSign: fetch a recent blockhash via JSON-RPC getLatestBlockhash,
build a v0 message (one signer = the MPC release wallet as fee
payer, one recipient, lamport amount), serialize the bytes to be
signed. SPL token mode (when SourceMint is set) derives source +
destination ATAs via solana.FindAssociatedTokenAddress and probes
the destination ATA via getAccountInfo — if absent, the assembler
prepends a CreateAssociatedTokenAccount instruction so the release
wallet pays the ~2_039_280 lamport rent + creates the account.
- Finalize: slot the 64-byte Ed25519 signature into Transaction
.Signatures[0], serialize the full wire tx with MarshalBinary, and
base64-encode for JSON-RPC sendTransaction (encoding:base64). The
signature itself doubles as the canonical Solana "tx hash" — return
it base58-encoded for SDK consumption.
Dependency: github.com/gagliardetto/solana-go v1.20.0 — the de facto
standard Go client. The assembler stays decoupled from the broader
*rpc.Client beyond GetLatestBlockhash + GetAccountInfo, so the
broadcast layer can use its own JSON-RPC endpoint.
Helpers:
- LamportsFromFloat(amount, decimals): safe float → uint64 conversion
with overflow protection. 9dp for native SOL; varies for SPL.
- ParseSOLSignatureHex(s): decodes a 128-char hex string to a fixed
[64]byte buffer — used by the signing driver when the dashboard
returns the Ed25519 sig in hex form.
- SOLDefaultBlockhashURL(network): canonical RPC URL per network.
Tests (sol_test.go) cover:
- Native transfer happy path: instruction is system.Transfer at
Account[0] = payer; round-trip of MessageBytes through
Message.Unmarshal yields an identical message.
- SPL transfer with destination ATA missing: 2 instructions
(ata.Create, then token.Transfer), destination ATA correctly
derived and probed.
- SPL transfer with destination ATA present: only 1 instruction.
- Finalize round-trip: rawTx parses back through solana-go's
Transaction decoder with matching signature + payer + blockhash.
- Error paths: unknown network, zero amount, malformed payer addr.
- ParseSOLSignatureHex + LamportsFromFloat: corner cases.
Total: 12 SOL tests, all green.