Auto merge of #4257 - oxarbitrage:issue4004, r=str4d

Delete SignatureHash from python script framework

Fixes https://github.com/zcash/zcash/issues/4004

Code is not used anywhere.

qa/rpc-tests/test_framework/script.py

@@ -11,8 +11,6 @@
 Functionality to build scripts, as well as SignatureHash().
 """
 
-from test_framework.mininode import CTransaction, CTxOut, hash256
-
 import sys
 bchr = chr
 bord = ord
@@ -816,77 +814,3 @@ class CScript(bytes):
                     n += 20
             lastOpcode = opcode
         return n
-
-
-SIGHASH_ALL = 1
-SIGHASH_NONE = 2
-SIGHASH_SINGLE = 3
-SIGHASH_ANYONECANPAY = 0x80
-
-def FindAndDelete(script, sig):
-    """Consensus critical, see FindAndDelete() in Satoshi codebase"""
-    r = b''
-    last_sop_idx = sop_idx = 0
-    skip = True
-    for (opcode, data, sop_idx) in script.raw_iter():
-        if not skip:
-            r += script[last_sop_idx:sop_idx]
-        last_sop_idx = sop_idx
-        if script[sop_idx:sop_idx + len(sig)] == sig:
-            skip = True
-        else:
-            skip = False
-    if not skip:
-        r += script[last_sop_idx:]
-    return CScript(r)
-
-
-def SignatureHash(script, txTo, inIdx, hashtype):
-    """Consensus-correct SignatureHash
-
-    Returns (hash, err) to precisely match the consensus-critical behavior of
-    the SIGHASH_SINGLE bug. (inIdx is *not* checked for validity)
-    """
-    HASH_ONE = b'\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'
-
-    if inIdx >= len(txTo.vin):
-        return (HASH_ONE, "inIdx %d out of range (%d)" % (inIdx, len(txTo.vin)))
-    txtmp = CTransaction(txTo)
-
-    for txin in txtmp.vin:
-        txin.scriptSig = b''
-    txtmp.vin[inIdx].scriptSig = FindAndDelete(script, CScript([OP_CODESEPARATOR]))
-
-    if (hashtype & 0x1f) == SIGHASH_NONE:
-        txtmp.vout = []
-
-        for i in range(len(txtmp.vin)):
-            if i != inIdx:
-                txtmp.vin[i].nSequence = 0
-
-    elif (hashtype & 0x1f) == SIGHASH_SINGLE:
-        outIdx = inIdx
-        if outIdx >= len(txtmp.vout):
-            return (HASH_ONE, "outIdx %d out of range (%d)" % (outIdx, len(txtmp.vout)))
-
-        tmp = txtmp.vout[outIdx]
-        txtmp.vout = []
-        for i in range(outIdx):
-            txtmp.vout.append(CTxOut())
-        txtmp.vout.append(tmp)
-
-        for i in range(len(txtmp.vin)):
-            if i != inIdx:
-                txtmp.vin[i].nSequence = 0
-
-    if hashtype & SIGHASH_ANYONECANPAY:
-        tmp = txtmp.vin[inIdx]
-        txtmp.vin = []
-        txtmp.vin.append(tmp)
-
-    s = txtmp.serialize()
-    s += struct.pack(b"<I", hashtype)
-
-    hash = hash256(s)
-
-    return (hash, None)