commit 9336d813ed573dda101e4bd2e0528ab34457f697
Author: nolash <dev@holbrook.no>
Date:   Fri Nov 13 18:33:39 2020 +0100

    Initial commit

diff --git a/registry.abi.json b/registry.abi.json
new file mode 100644
index 0000000..611f3db
--- /dev/null
+++ b/registry.abi.json
@@ -0,0 +1 @@
+[{"inputs":[],"stateMutability":"nonpayable","type":"constructor"},{"anonymous":false,"inputs":[{"indexed":true,"internalType":"address","name":"addedAccount","type":"address"},{"indexed":true,"internalType":"uint256","name":"accountIndex","type":"uint256"}],"name":"AccountAdded","type":"event"},{"inputs":[{"internalType":"uint256","name":"","type":"uint256"}],"name":"accounts","outputs":[{"internalType":"address","name":"","type":"address"}],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"address","name":"","type":"address"}],"name":"accountsIndex","outputs":[{"internalType":"uint256","name":"","type":"uint256"}],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"address","name":"_account","type":"address"}],"name":"add","outputs":[],"stateMutability":"nonpayable","type":"function"},{"inputs":[{"internalType":"address","name":"_writer","type":"address"}],"name":"addWriter","outputs":[],"stateMutability":"nonpayable","type":"function"},{"inputs":[],"name":"count","outputs":[{"internalType":"uint256","name":"","type":"uint256"}],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"address","name":"_writer","type":"address"}],"name":"deleteWriter","outputs":[],"stateMutability":"nonpayable","type":"function"}]
diff --git a/registry.bin b/registry.bin
new file mode 100644
index 0000000..82dbdf4
--- /dev/null
+++ b/registry.bin
@@ -0,0 +1 @@
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
\ No newline at end of file
diff --git a/registry.sol b/registry.sol
new file mode 100644
index 0000000..ebc84d3
--- /dev/null
+++ b/registry.sol
@@ -0,0 +1,36 @@
+pragma solidity ^0.7.3;
+
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+contract CustodialAccountIndex {
+
+	address[] public accounts;
+	mapping(address => uint256) public accountsIndex;
+	uint256 public count;
+	mapping(address => bool) writers;
+	address owner;
+
+	event AccountAdded(address indexed addedAccount, uint256 indexed accountIndex);
+
+	constructor() {
+		owner = msg.sender;
+	}
+
+	function addWriter(address _writer) public {
+		require(owner == msg.sender);
+		writers[_writer] = true;
+	}
+
+	function deleteWriter(address _writer) public {
+		require(owner == msg.sender);
+		delete writers[_writer];
+	}
+
+	function add(address _account) public {
+		require(writers[msg.sender]);
+		accounts.push(_account);
+		accountsIndex[_account] = count;
+		count++;
+		emit AccountAdded(_account, count-1);
+	}
+}
diff --git a/test.py b/test.py
new file mode 100644
index 0000000..57fce01
--- /dev/null
+++ b/test.py
@@ -0,0 +1,42 @@
+import web3
+import eth_tester
+import json
+
+
+eth_params = eth_tester.backends.pyevm.main.get_default_genesis_params({
+    'gas_limit': 9000000,
+    })
+backend = eth_tester.PyEVMBackend(eth_params)
+instance = eth_tester.EthereumTester(backend)
+provider = web3.Web3.EthereumTesterProvider(instance)
+w3 = web3.Web3(provider)
+
+
+f = open('registry.bin', 'r')
+bytecode = f.read()
+f.close()
+
+f = open('registry.abi.json', 'r')
+abi = json.load(f)
+f.close()
+
+c = w3.eth.contract(abi=abi, bytecode=bytecode)
+tx_hash = c.constructor().transact({'from': w3.eth.accounts[0]})
+
+r = w3.eth.getTransactionReceipt(tx_hash)
+
+c = w3.eth.contract(abi=abi, address=r.contractAddress)
+fail = False
+try:
+    c.functions.add(w3.eth.accounts[2]).transact({'from': w3.eth.accounts[1]})
+except:
+    fail = True
+assert fail
+
+c.functions.addWriter(w3.eth.accounts[1]).transact({'from': w3.eth.accounts[0]})
+c.functions.add(w3.eth.accounts[2]).transact({'from': w3.eth.accounts[1]})
+c.functions.add(w3.eth.accounts[3]).transact({'from': w3.eth.accounts[1]})
+
+assert c.functions.count().call() == 2
+assert c.functions.accountsIndex(w3.eth.accounts[3]).call() == 1
+assert c.functions.accounts(1).call() == w3.eth.accounts[3]