Add a GC debugger

Add commented-out GC debugging step

gui/qt/__init__.py

@@ -34,6 +34,10 @@ from electrum.plugins import run_hook
 from electrum import SimpleConfig, Wallet, WalletStorage
 from electrum.paymentrequest import InvoiceStore
 from electrum.contacts import Contacts
+from electrum.synchronizer import Synchronizer
+from electrum.verifier import SPV
+from electrum.util import DebugMem
+from electrum.wallet import Abstract_Wallet
 from installwizard import InstallWizard
 
 
@@ -64,6 +68,10 @@ class ElectrumGui:
 
     def __init__(self, config, network, plugins):
         set_language(config.get('language'))
+        # Uncomment this call to verify objects are being properly
+        # GC-ed when windows are closed
+        #network.add_jobs([DebugMem([Abstract_Wallet, SPV, Synchronizer,
+        #                            ElectrumWindow], interval=5)])
         self.network = network
         self.config = config
         self.plugins = plugins

lib/util.py

@@ -1,6 +1,7 @@
 import os, sys, re, json
 import platform
 import shutil
+from collections import defaultdict
 from datetime import datetime
 from decimal import Decimal
 import traceback
@@ -45,6 +46,31 @@ class ThreadJob(PrintError):
         """Called periodically from the thread"""
         pass
 
+class DebugMem(ThreadJob):
+    '''A handy class for debugging GC memory leaks'''
+    def __init__(self, classes, interval=30):
+        self.next_time = 0
+        self.classes = classes
+        self.interval = interval
+
+    def mem_stats(self):
+        import gc
+        self.print_error("Start memscan")
+        gc.collect()
+        objmap = defaultdict(list)
+        for obj in gc.get_objects():
+            for class_ in self.classes:
+                if isinstance(obj, class_):
+                    objmap[class_].append(obj)
+        for class_, objs in objmap.items():
+            self.print_error("%s: %d" % (class_.__name__, len(objs)))
+        self.print_error("Finish memscan")
+
+    def run(self):
+        if time.time() > self.next_time:
+            self.mem_stats()
+            self.next_time = time.time() + self.interval
+
 class DaemonThread(threading.Thread, PrintError):
     """ daemon thread that terminates cleanly """
 
@@ -555,4 +581,3 @@ def check_www_dir(rdir):
         if not os.path.exists(path):
             print_error("downloading ", URL)
             urllib.urlretrieve(URL, path)
-