Genericize plugin handling of thread jobs

Move it to the Plugins class so all plugins get it for
free.

lib/plugins.py

@@ -26,6 +26,13 @@ from util import *
 from i18n import _
 from util import print_error, profiler
 
+hook_names = set()
+hooks = {}
+
+def hook(func):
+    hook_names.add(func.func_name)
+    return func
+
 class Plugins:
 
     @profiler
@@ -40,6 +47,7 @@ class Plugins:
 
         self.plugins = {}
         self.windows = []
+        self.network = None
         self.descriptions = plugins.descriptions
         for item in self.descriptions:
             name = item['name']
@@ -118,6 +126,17 @@ class Plugins:
         x += (lambda: self.wallet_plugin_loader(config, name),)
         wallet.wallet_types.append(x)
 
+    @hook
+    def set_network(self, network):
+        if network != self.network:
+            jobs = [job in plugin.thread_jobs()
+                    for plugin in self.plugins.values()]
+            if self.network:
+                self.network.remove_jobs(jobs)
+            self.network = network
+            if network:
+                network.add_jobs(jobs)
+
     def trigger(self, event, *args, **kwargs):
         for plugin in self.plugins.values():
             getattr(plugin, event)(*args, **kwargs)
@@ -130,13 +149,6 @@ class Plugins:
         self.windows.remove(window)
         self.trigger('on_close_window', window)
 
-hook_names = set()
-hooks = {}
-
-def hook(func):
-    hook_names.add(func.func_name)
-    return func
-
 def run_hook(name, *args):
     return _run_hook(name, False, *args)
 
@@ -194,6 +206,9 @@ class BasePlugin:
     def requires_settings(self):
         return False
 
+    def thread_jobs(self):
+        return []
+
     @hook
     def load_wallet(self, wallet, window): pass