From 0243e422e53823f9149ffa6a851113e2917c8ffe Mon Sep 17 00:00:00 2001
From: Ben Lubar <ben.lubar@gmail.com>
Date: Fri, 7 Feb 2020 16:00:14 -0600
Subject: [PATCH] Allow plugins to define subclasses of dfhack_viewscreen that
 have their own virtual_identity.

---
 library/DataDefs.cpp       | 29 ++++++++++++++++++++++-------
 library/include/DataDefs.h |  5 ++++-
 library/modules/Gui.cpp    | 12 ++++++------
 3 files changed, 32 insertions(+), 14 deletions(-)

diff --git a/library/DataDefs.cpp b/library/DataDefs.cpp
index 3d802638f..5952e3da1 100644
--- a/library/DataDefs.cpp
+++ b/library/DataDefs.cpp
@@ -226,12 +226,24 @@ std::string df::buffer_container_identity::getFullName(type_identity *item)
 
 virtual_identity::virtual_identity(size_t size, TAllocateFn alloc,
                                    const char *dfhack_name, const char *original_name,
-                                   virtual_identity *parent, const struct_field_info *fields)
+                                   virtual_identity *parent, const struct_field_info *fields,
+                                   bool is_plugin)
     : struct_identity(size, alloc, NULL, dfhack_name, parent, fields), original_name(original_name),
-      vtable_ptr(NULL)
+      vtable_ptr(NULL), is_plugin(is_plugin)
 {
+    // Plugins are initialized after Init was called, so they need to be added to the name table here
+    if (is_plugin)
+    {
+        doInit(&Core::getInstance());
+    }
 }
 
+/* Vtable name to identity lookup. */
+static std::map<std::string, virtual_identity*> name_lookup;
+
+/* Vtable pointer to identity lookup. */
+std::map<void*, virtual_identity*> virtual_identity::known;
+
 virtual_identity::~virtual_identity()
 {
     // Remove interpose entries, so that they don't try accessing this object later
@@ -239,13 +251,16 @@ virtual_identity::~virtual_identity()
         if (it->second)
             it->second->on_host_delete(this);
     interpose_list.clear();
-}
 
-/* Vtable name to identity lookup. */
-static std::map<std::string, virtual_identity*> name_lookup;
+    // Remove global lookup table entries if we're from a plugin
+    if (is_plugin)
+    {
+        name_lookup.erase(getOriginalName());
 
-/* Vtable pointer to identity lookup. */
-std::map<void*, virtual_identity*> virtual_identity::known;
+        if (vtable_ptr)
+            known.erase(vtable_ptr);
+    }
+}
 
 void virtual_identity::doInit(Core *core)
 {
diff --git a/library/include/DataDefs.h b/library/include/DataDefs.h
index 7c3b534b6..750c4d70a 100644
--- a/library/include/DataDefs.h
+++ b/library/include/DataDefs.h
@@ -321,6 +321,8 @@ namespace DFHack
 
         void *vtable_ptr;
 
+        bool is_plugin;
+
         friend class VMethodInterposeLinkBase;
         std::map<int,VMethodInterposeLinkBase*> interpose_list;
 
@@ -337,7 +339,8 @@ namespace DFHack
     public:
         virtual_identity(size_t size, TAllocateFn alloc,
                          const char *dfhack_name, const char *original_name,
-                         virtual_identity *parent, const struct_field_info *fields);
+                         virtual_identity *parent, const struct_field_info *fields,
+                         bool is_plugin = false);
         ~virtual_identity();
 
         virtual identity_type type() { return IDTYPE_CLASS; }
diff --git a/library/modules/Gui.cpp b/library/modules/Gui.cpp
index 758395f40..b4c4a7693 100644
--- a/library/modules/Gui.cpp
+++ b/library/modules/Gui.cpp
@@ -591,7 +591,12 @@ std::string Gui::getFocusString(df::viewscreen *top)
     if (!top)
         return "";
 
-    if (virtual_identity *id = virtual_identity::get(top))
+    if (dfhack_viewscreen::is_instance(top))
+    {
+        auto name = static_cast<dfhack_viewscreen*>(top)->getFocusString();
+        return name.empty() ? "dfhack" : "dfhack/"+name;
+    }
+    else if (virtual_identity *id = virtual_identity::get(top))
     {
         std::string name = getNameChunk(id, 11, 2);
 
@@ -601,11 +606,6 @@ std::string Gui::getFocusString(df::viewscreen *top)
 
         return name;
     }
-    else if (dfhack_viewscreen::is_instance(top))
-    {
-        auto name = static_cast<dfhack_viewscreen*>(top)->getFocusString();
-        return name.empty() ? "dfhack" : "dfhack/"+name;
-    }
     else
     {
         Core &core = Core::getInstance();