Add a partial support for vote program (#167)

* Add a partial support for vote program

* Add tests

* Add some comments

* Fix linting errors

src/solana/_layouts/vote_instructions.py

@@ -0,0 +1,26 @@
+"""Byte layouts for vote program instructions."""
+from enum import IntEnum
+
+from construct import Switch  # type: ignore
+from construct import Int32ul, Int64ul
+from construct import Struct as cStruct
+
+
+class InstructionType(IntEnum):
+    """Instruction types for vote program."""
+
+    WITHDRAW_FROM_VOTE_ACCOUNT = 3
+
+
+_WITHDRAW_FROM_VOTE_ACCOUNT_LAYOUT = cStruct("lamports" / Int64ul)
+
+VOTE_INSTRUCTIONS_LAYOUT = cStruct(
+    "instruction_type" / Int32ul,
+    "args"
+    / Switch(
+        lambda this: this.instruction_type,
+        {
+            InstructionType.WITHDRAW_FROM_VOTE_ACCOUNT: _WITHDRAW_FROM_VOTE_ACCOUNT_LAYOUT,
+        },
+    ),
+)

src/solana/vote_program.py

@@ -0,0 +1,58 @@
+"""Library to interface with the vote program."""
+from __future__ import annotations
+
+from typing import NamedTuple
+
+from solana._layouts.vote_instructions import VOTE_INSTRUCTIONS_LAYOUT, InstructionType
+from solana.publickey import PublicKey
+from solana.transaction import AccountMeta, TransactionInstruction
+
+VOTE_PROGRAM_ID: PublicKey = PublicKey("Vote111111111111111111111111111111111111111")
+"""Public key that identifies the Vote program."""
+
+
+# Instrection Params
+class WithdrawFromVoteAccountParams(NamedTuple):
+    """Transfer SOL from vote account to identity."""
+
+    vote_account_from_pubkey: PublicKey
+    """"""
+    to_pubkey: PublicKey
+    """"""
+    lamports: int
+    """"""
+    withdrawer: PublicKey
+    """"""
+
+
+def withdraw_from_vote_account(params: WithdrawFromVoteAccountParams) -> TransactionInstruction:
+    """Generate an instruction that transfers lamports from a vote account to any other.
+
+    >>> from solana.publickey import PublicKey
+    >>> from solana.keypair import Keypair
+    >>> vote = PublicKey(1)
+    >>> withdrawer = Keypair.from_seed(bytes([0]*32))
+    >>> instruction = withdraw_from_vote_account(
+    ...    WithdrawFromVoteAccountParams(
+    ...        vote_account_from_pubkey=vote,
+    ...        to_pubkey=withdrawer,
+    ...        withdrawer=withdrawer,
+    ...        lamports=3_000_000_000,
+    ...    )
+    ... )
+    >>> type(instruction)
+    <class 'solana.transaction.TransactionInstruction'>
+    """
+    data = VOTE_INSTRUCTIONS_LAYOUT.build(
+        dict(instruction_type=InstructionType.WITHDRAW_FROM_VOTE_ACCOUNT, args=dict(lamports=params.lamports))
+    )
+
+    return TransactionInstruction(
+        keys=[
+            AccountMeta(pubkey=params.vote_account_from_pubkey, is_signer=False, is_writable=True),
+            AccountMeta(pubkey=params.to_pubkey, is_signer=False, is_writable=True),
+            AccountMeta(pubkey=params.withdrawer, is_signer=True, is_writable=True),
+        ],
+        program_id=VOTE_PROGRAM_ID,
+        data=data,
+    )

tests/unit/test_vote_program.py

@@ -0,0 +1,109 @@
+"""Unit tests for solana.vote_program."""
+import base64
+
+import solana.vote_program as vp
+import solana.transaction as txlib
+from solana.keypair import Keypair
+from solana.publickey import PublicKey
+
+
+def test_withdraw_from_vote_account():
+    withdrawer_keypair = Keypair.from_secret_key(
+        bytes(
+            [
+                134,
+                123,
+                27,
+                208,
+                227,
+                175,
+                253,
+                99,
+                4,
+                81,
+                170,
+                231,
+                186,
+                141,
+                177,
+                142,
+                197,
+                139,
+                94,
+                6,
+                157,
+                2,
+                163,
+                89,
+                150,
+                121,
+                235,
+                86,
+                185,
+                22,
+                1,
+                233,
+                58,
+                133,
+                229,
+                39,
+                212,
+                71,
+                254,
+                72,
+                246,
+                45,
+                160,
+                156,
+                129,
+                199,
+                18,
+                189,
+                53,
+                143,
+                98,
+                72,
+                182,
+                106,
+                69,
+                29,
+                38,
+                145,
+                119,
+                190,
+                13,
+                105,
+                157,
+                112,
+            ]
+        )
+    )
+    vote_account_pubkey = PublicKey("CWqJy1JpmBcx7awpeANfrPk6AsQKkmego8ujjaYPGFEk")
+    receiver_account_pubkey = PublicKey("A1V5gsis39WY42djdTKUFsgE5oamk4nrtg16WnKTuzZK")
+
+    # solana withdraw-from-vote-account --dump-transaction-message \
+    #   CWqJy1JpmBcx7awpeANfrPk6AsQKkmego8ujjaYPGFEk A1V5gsis39WY42djdTKUFsgE5oamk4nrtg16WnKTuzZK \
+    # --authorized-withdrawer withdrawer.json \
+    # 2 \
+    # --blockhash Add1tV7kJgNHhTtx3Dgs6dhC7kyXrGJQZ2tJGW15tLDH \
+    # --sign-only -k withdrawer.json
+    wire_msg = base64.b64decode(
+        b"AQABBDqF5SfUR/5I9i2gnIHHEr01j2JItmpFHSaRd74NaZ1wqxUGDtH5ah3TqEKWjcTmfHkpZC1h57NJL8Sx7Q6Olm2F2O70oOvzt1HgIVu+nySaSrWtJiK1eDacPPDWRxCwFgdhSB01dHS7fE12JOvTvbPYNV5z0RBD/A2jU4AAAAAAjxrQaMS7FjmaR++mvFr3XE6XbzMUTMJUIpITrUWBzGwBAwMBAgAMAwAAAACUNXcAAAAA"  # noqa: E501 pylint: disable=line-too-long
+    )
+
+    txn = txlib.Transaction(fee_payer=withdrawer_keypair.public_key)
+    txn.recent_blockhash = "Add1tV7kJgNHhTtx3Dgs6dhC7kyXrGJQZ2tJGW15tLDH"
+
+    txn.add(
+        vp.withdraw_from_vote_account(
+            vp.WithdrawFromVoteAccountParams(
+                vote_account_from_pubkey=vote_account_pubkey,
+                to_pubkey=receiver_account_pubkey,
+                withdrawer=withdrawer_keypair.public_key,
+                lamports=2_000_000_000,
+            )
+        )
+    )
+
+    serialized_message = txn.serialize_message()
+    assert serialized_message == wire_msg