vaa-processor pyteal wip

teal/wormhole/pyteal/vaa-processor.py

@@ -0,0 +1,131 @@
+#!/usr/bin/python3
+"""
+================================================================================================
+
+The VAA Processor Program
+
+(c) 2021 Randlabs, Inc.
+
+------------------------------------------------------------------------------------------------
+
+This program is the core client to signed VAAs from Wormhole, working in tandem with the
+verify-vaa.teal stateless programs.
+
+The following application calls are available.
+
+prepare:   Load globals in scatchspace to be used by stateless programs. Must be TX#0.
+verify:  Verify guardian signature subset i..j, works in tandem with stateless program
+commit:  Commit verified VAA, processing it according to its payload. Must be last TX.
+
+------------------------------------------------------------------------------------------------
+
+Global state:
+
+"gsexp"    :  Guardian set expiration time
+"gscount"  :  Guardian set size
+key N      :  address of guardian N
+
+------------------------------------------------------------------------------------------------
+Stores in scratch: 
+
+SLOT 254:  uint64 with bit field of approved guardians (initial 0)
+SLOT 255:  number of guardians in set 
+SLOT 4*i:  key of guardian i  (as of Nov'21 there are 19 guardians)
+================================================================================================
+
+"""
+from pyteal import (compileTeal, Int, Mode, Txn, OnComplete,
+                    Return, Cond, Bytes, Global, Not, Seq, Approve, App, Assert, For, And)
+import pyteal
+from pyteal.ast.binaryexpr import ShiftRight
+from pyteal.ast.if_ import If
+from pyteal.ast.return_ import Reject
+from pyteal.ast.scratch import ScratchLoad, ScratchSlot
+from pyteal.ast.scratchvar import ScratchVar
+from pyteal.ast.subroutine import Subroutine
+from pyteal.ast.while_ import While
+from pyteal.types import TealType
+
+METHOD = Txn.application_args[0]
+
+# Bootstrap with the initial list of guardians as application argument
+
+
+@Subroutine(TealType.uint64)
+def bootstrap():
+    return Seq([
+        Approve()
+    ])
+
+
+@Subroutine(TealType.uint64)
+def is_creator():
+    return Txn.sender() == Global.creator_address()
+
+
+@Subroutine(TealType.uint64)
+def is_proper_group_size():
+    return Global.group_size() >= Int(3)
+
+
+def prepare():
+    # Sender must be owner
+    # This call must be index 0 in a group of minimum 3 (prepare->verify->commit)
+    Assert(And(is_creator(),
+               is_proper_group_size(), Txn.group_index() == Int(0)))
+
+    i = ScratchVar(TealType.uint64, 253)
+    gs_count = ScratchVar(TealType.uint64, 254)
+    num_guardians = App.globalGet(Bytes("gscount"))
+    If(num_guardians == Int(0), Reject(), Seq([
+        gs_count.store(num_guardians),
+        For(i.store(Int(0)), i.load() < num_guardians, i.store(i.load() + Int(1))).Do(
+            Seq([
+                
+                # (ScratchVar(TealType.uint64, i.load())).store(App.globalGet(Itob(i.load()))
+            ]))
+    ]))
+    return Approve()
+
+
+def verify():
+    # This call must be not the first or last in a group of minimum 3 (prepare->verify->commit)
+    return Seq([Assert(And(is_proper_group_size(),
+                       Txn.group_index() < Global.group_size(),
+                       Txn.group_index() > Int(0))),
+                Approve()])
+
+
+def commit():
+    # Sender must be owner
+    # This call must be last in a group of minimum 3 (prepare->verify->commit)
+    return Seq([
+        Assert(And(is_proper_group_size(), Txn.group_index()
+               == (Global.group_size() - Int(1)))),
+        Approve()
+    ])
+
+
+def vaa_processor_program():
+    handle_create = Return(bootstrap())
+    handle_update = Return(is_creator())
+    handle_delete = Return(is_creator())
+    handle_noop = Cond(
+        [METHOD == Bytes("prepare"), prepare()],
+        [METHOD == Bytes("verify"), verify()],
+        [METHOD == Bytes("commit"), commit()]
+    )
+    return Cond(
+        [Not(Txn.application_id()), handle_create],
+        [Txn.on_completion() == OnComplete.UpdateApplication, handle_update],
+        [Txn.on_completion() == OnComplete.DeleteApplication, handle_delete],
+        [Txn.on_completion() == OnComplete.NoOp, handle_noop]
+    )
+
+
+def clear_state_program():
+    Return(Int(1))
+
+
+if __name__ == "__main__":
+    print(compileTeal(vaa_processor_program(), mode=Mode.Application, version=5))