From 7f3b627aa4d9e55e25a445de47b5badd9ed5d304 Mon Sep 17 00:00:00 2001
From: SomberNight <somber.night@protonmail.com>
Date: Sat, 27 Jan 2018 17:33:26 +0100
Subject: [PATCH] make wallet.get_address_index faster by storing an
 addr->index dict

---
 gui/qt/main_window.py |  2 ++
 lib/wallet.py         | 22 +++++++++++++++++-----
 2 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/gui/qt/main_window.py b/gui/qt/main_window.py
index fb66005e..59367321 100644
--- a/gui/qt/main_window.py
+++ b/gui/qt/main_window.py
@@ -62,6 +62,7 @@ from .fee_slider import FeeSlider
 
 from .util import *
 
+from electrum.util import profiler
 
 class StatusBarButton(QPushButton):
     def __init__(self, icon, tooltip, func):
@@ -325,6 +326,7 @@ class ElectrumWindow(QMainWindow, MessageBoxMixin, PrintError):
             self.print_error('close_wallet', self.wallet.storage.path)
         run_hook('close_wallet', self.wallet)
 
+    @profiler
     def load_wallet(self, wallet):
         wallet.thread = TaskThread(self, self.on_error)
         self.wallet = wallet
diff --git a/lib/wallet.py b/lib/wallet.py
index a9dc646b..11337bc9 100644
--- a/lib/wallet.py
+++ b/lib/wallet.py
@@ -340,6 +340,8 @@ class Abstract_Wallet(PrintError):
         return address in self.change_addresses
 
     def get_address_index(self, address):
+        if hasattr(self, '_addr_to_addr_index'):
+            return self._addr_to_addr_index[address]
         if address in self.receiving_addresses:
             return False, self.receiving_addresses.index(address)
         if address in self.change_addresses:
@@ -1029,8 +1031,10 @@ class Abstract_Wallet(PrintError):
 
     def is_used(self, address):
         h = self.history.get(address,[])
+        if len(h) == 0:
+            return False
         c, u, x = self.get_addr_balance(address)
-        return len(h) > 0 and c + u + x == 0
+        return c + u + x == 0
 
     def is_empty(self, address):
         c, u, x = self.get_addr_balance(address)
@@ -1647,6 +1651,14 @@ class Deterministic_Wallet(Abstract_Wallet):
                 if n > nmax: nmax = n
         return nmax + 1
 
+    def load_addresses(self):
+        super().load_addresses()
+        self._addr_to_addr_index = {}  # key: address, value: (is_change, index)
+        for i, addr in enumerate(self.receiving_addresses):
+            self._addr_to_addr_index[addr] = (False, i)
+        for i, addr in enumerate(self.change_addresses):
+            self._addr_to_addr_index[addr] = (True, i)
+
     def create_new_address(self, for_change=False):
         assert type(for_change) is bool
         addr_list = self.change_addresses if for_change else self.receiving_addresses
@@ -1654,6 +1666,7 @@ class Deterministic_Wallet(Abstract_Wallet):
         x = self.derive_pubkeys(for_change, n)
         address = self.pubkeys_to_address(x)
         addr_list.append(address)
+        self._addr_to_addr_index[address] = (for_change, n)
         self.save_addresses()
         self.add_address(address)
         return address
@@ -1685,12 +1698,11 @@ class Deterministic_Wallet(Abstract_Wallet):
 
     def is_beyond_limit(self, address, is_change):
         addr_list = self.get_change_addresses() if is_change else self.get_receiving_addresses()
-        i = addr_list.index(address)
-        prev_addresses = addr_list[:max(0, i)]
+        i = self.get_address_index(address)[1]
         limit = self.gap_limit_for_change if is_change else self.gap_limit
-        if len(prev_addresses) < limit:
+        if i < limit:
             return False
-        prev_addresses = prev_addresses[max(0, i - limit):]
+        prev_addresses = addr_list[max(0, i - limit):max(0, i)]
         for addr in prev_addresses:
             if self.history.get(addr):
                 return False