From 122ef02605a9c8df23292fd76cc18b47bca949ea Mon Sep 17 00:00:00 2001
From: ZeroNet <git@zeronet.io>
Date: Wed, 10 Aug 2016 12:43:35 +0200
Subject: [PATCH] Hot-patch in memory plugin classes

---
 src/Plugin/PluginManager.py | 50 ++++++++++++++++++++++++++++++++++---
 1 file changed, 46 insertions(+), 4 deletions(-)

diff --git a/src/Plugin/PluginManager.py b/src/Plugin/PluginManager.py
index c1069da7..c9fc14e1 100644
--- a/src/Plugin/PluginManager.py
+++ b/src/Plugin/PluginManager.py
@@ -1,17 +1,18 @@
 import logging
 import os
 import sys
+from collections import defaultdict
 
 from Debug import Debug
 from Config import config
 
 
 class PluginManager:
-
     def __init__(self):
         self.log = logging.getLogger("PluginManager")
         self.plugin_path = "plugins"  # Plugin directory
-        self.plugins = {}  # Registered plugins (key: class name, value: list of plugins for class)
+        self.plugins = defaultdict(list)  # Registered plugins (key: class name, value: list of plugins for class)
+        self.pluggable = {}
         self.plugin_names = []  # Loaded plugin names
 
         sys.path.append(self.plugin_path)
@@ -42,10 +43,18 @@ class PluginManager:
 
     # Reload all plugins
     def reloadPlugins(self):
-        self.plugins = {}  # Reset registered plugins
+        self.plugins_before = self.plugins
+        self.plugins = defaultdict(list)  # Reset registered plugins
         for module_name, module in sys.modules.items():
             if module and "__file__" in dir(module) and self.plugin_path in module.__file__:  # Module file within plugin_path
-                if "allow_reload" not in dir(module) or module.allow_reload:  # Check if reload disabled
+                if "allow_reload" in dir(module) and not module.allow_reload:  # Reload disabled
+                    # Re-add non-reloadable plugins
+                    for class_name, classes in self.plugins_before.iteritems():
+                        for c in classes:
+                            if c.__module__ != module.__name__:
+                                continue
+                            self.plugins[class_name].append(c)
+                else:
                     try:
                         reload(module)
                     except Exception, err:
@@ -53,6 +62,38 @@ class PluginManager:
 
         self.loadPlugins()  # Load new plugins
 
+        # Change current classes in memory
+        import gc
+        patched = {}
+        for class_name, classes in self.plugins.iteritems():
+            classes = classes[:]  # Copy the current plugins
+            classes.reverse()
+            base_class = self.pluggable[class_name]  # Original class
+            classes.append(base_class)  # Add the class itself to end of inherience line
+            plugined_class = type(class_name, tuple(classes), dict())  # Create the plugined class
+            for obj in gc.get_objects():
+                if type(obj).__name__ == class_name:
+                    obj.__class__ = plugined_class
+                    patched[class_name] = patched.get(class_name, 0) + 1
+        self.log.debug("Patched objects: %s" % patched)
+
+        # Change classes in modules
+        patched = {}
+        for class_name, classes in self.plugins.iteritems():
+            for module_name, module in sys.modules.iteritems():
+                if class_name in dir(module):
+                    if "__class__" not in dir(getattr(module, class_name)):  # Not a class
+                        continue
+                    base_class = self.pluggable[class_name]
+                    classes = self.plugins[class_name][:]
+                    classes.reverse()
+                    classes.append(base_class)
+                    plugined_class = type(class_name, tuple(classes), dict())
+                    setattr(module, class_name, plugined_class)
+                    patched[class_name] = patched.get(class_name, 0) + 1
+
+        self.log.debug("Patched modules: %s" % patched)
+
 
 plugin_manager = PluginManager()  # Singletone
 
@@ -63,6 +104,7 @@ plugin_manager = PluginManager()  # Singletone
 
 def acceptPlugins(base_class):
     class_name = base_class.__name__
+    plugin_manager.pluggable[class_name] = base_class
     if class_name in plugin_manager.plugins:  # Has plugins
         classes = plugin_manager.plugins[class_name][:]  # Copy the current plugins
         classes.reverse()