Change the creation/deletion of tangibles so that the tangible database is never really deleted.

luprex/cpp/core/luastack.cpp

@@ -376,6 +376,54 @@ void LuaStack::makeclass(LuaSlot tab, std::string_view name) const {
     lua_pop(L_, 1);
 }
 
+void LuaStack::maketan(LuaSlot tab, int64_t id) const {
+    LuaVar tangibles, metatab;
+    LuaStack LS(L_, tangibles, metatab);
+    
+    // Try to get the existing tangible.
+    LS.rawget(tangibles, LuaRegistry, "tangibles");
+    LS.rawget(tab, tangibles, id);
+
+    // If we succeeded, return it.
+    if (LS.istable(tab)) {
+        LS.result();
+        return;
+    }
+
+    // Create the tangible's database and metatable.
+    LS.set(tab, LuaNewTable);
+    LS.set(metatab, LuaNewTable);
+    LS.setmetatable(tab, metatab);
+
+    // Mark the tangible using the tabletype field.
+    LS.settabletype(tab, LUA_TT_TANGIBLE);
+    LS.settabletype(metatab, LUA_TT_TANGIBLEMETA);
+
+    // Store the tangible ID and lock the metatable.
+    LS.rawset(metatab, "id", id);
+    LS.rawset(metatab, "__metatable", false);
+
+    // Store the database into the tangibles table.
+    LS.rawset(tangibles, id, tab);
+
+    LS.result();
+}
+
+
+bool LuaStack::tanblank(LuaSlot tab) const {
+    bool result = true;
+    if (istable(tab) && gettabletype(tab) == LUA_TT_TANGIBLE) {
+        if (lua_getmetatable(L_, tab.index())) {
+            lua_pushstring(L_, "threads");
+            lua_rawget(L_, -2);
+            if (lua_type(L_, -1) == LUA_TTABLE) {
+                result = false;
+            }
+            lua_pop(L_, 2);
+        }
+    }
+    return result;
+}
 
 int64_t LuaStack::tanid(LuaSlot tab) const {
     int64_t result = 0;

luprex/cpp/core/luastack.hpp

@@ -222,9 +222,8 @@ int LuaTypeTagValue(lua_State *L) { return 0; }
 #define LUA_TT_GLOBALENV     18
 #define LUA_TT_TANGIBLE      19
 #define LUA_TT_TANGIBLEMETA  20
-#define LUA_TT_DEADTANGIBLE  21
+#define LUA_TT_GLOBALDB      21
-#define LUA_TT_GLOBALDB      22
+#define LUA_TT_CLASS         22
-#define LUA_TT_CLASS         23
 
 // World types enum.
 
@@ -458,8 +457,16 @@ public:
     void makeclass(LuaSlot tab, LuaSlot name) const;
     void makeclass(LuaSlot tab, std::string_view name) const;
 
-    // Get the ID of a tangible.  It's a little weird to put this in
+    // Create a tangible, or look up an existing tangible.
-    // this module.
+    // This doesn't do the entire process of tangible creation.  It
+    // just creates an empty table, marks it as a tangible, creates
+    // the metatable, stores the tangible ID, and stores it in the tangible table.
+    void maketan(LuaSlot tab, int64_t id) const;
+
+    // Return true if a tangible is empty (deleted or not yet created).
+    bool tanblank(LuaSlot tab) const;
+
+    // Get the ID of a tangible.
     int64_t tanid(LuaSlot tab) const;
 
     // Return true if the value is a sortable key (string, number, or boolean).

luprex/cpp/core/pprint.cpp

@@ -78,6 +78,10 @@ public:
             (*output_) << "<global-env>";
             return;
         }
+        case LUA_TT_TANGIBLEMETA: {
+            (*output_) << "<tangible-metatable>";
+            return;
+        }
         default: {
             (*output_) << "<unknown type #" << xtype << ">";
             return;
@@ -103,18 +107,16 @@ public:
 
         // Determine the extended type of the object. If the
         // expand flag is true, try to coerce it to a general table.
-        int type = LS.xtype(value);
+        int xtype = LS.xtype(value);
-        if (expand && (LS.istable(value))) {
-            type = LUA_TT_GENERAL;
-        }
 
-        // If it's anything but a general table, use 'atomic_print'
+        // Print the atomic portion.
-        // and return.
+        if (xtype != LUA_TT_GENERAL) {
-        if (type != LUA_TT_GENERAL) {
+            atomic_print(xtype, value, true);
-            atomic_print(type, value, true);
+            if ((xtype < LUA_TT_GENERAL) || (!expand)) {
                 LS.result();
                 return;
             }
+        }
 
         // Find out whether it has a table number.  If necessary,
         // assign one.
@@ -189,7 +191,7 @@ public:
 
         // Output the metatable.
         LS.getmetatable(val, value);
-        if (LS.istable(val)) {
+        if (LS.istable(val) && (LS.gettabletype(val) != LUA_TT_TANGIBLEMETA)) {
             multiline = true;
             if (needcomma) (*output_) << ",";
             needcomma = true;

luprex/cpp/core/world-accessor.cpp

@@ -26,7 +26,7 @@ LuaDefine(tangible_animstate, "tan",
     LuaRet graphic, plane, x, y, z, facing;
     LuaStack LS(L, tanobj, graphic, plane, x, y, z, facing);
     World *w = World::fetch_global_pointer(L);
-    Tangible *tan = w->tangible_get(LS, tanobj);
+    Tangible *tan = w->tangible_get(LS, tanobj, false);
     const AnimStep &aqback = tan->anim_queue_.back();
     LS.set(graphic, aqback.graphic());
     LS.set(plane, aqback.plane());
@@ -44,7 +44,7 @@ LuaDefine(tangible_xyz, "tan",
     LuaRet x, y, z;
     LuaStack LS(L, tanobj, x, y, z);
     World *w = World::fetch_global_pointer(L);
-    Tangible *tan = w->tangible_get(LS, tanobj);
+    Tangible *tan = w->tangible_get(LS, tanobj, false);
     const AnimStep &aqback = tan->anim_queue_.back();
     LS.set(x, aqback.xyz().x);
     LS.set(y, aqback.xyz().y);
@@ -60,7 +60,7 @@ LuaDefine(tangible_animate, "tan,configtable",
     LuaStack LS(L, tanobj, config);
     LuaKeywordParser kp(LS, config);
     World *w = World::fetch_global_pointer(L);
-    Tangible *tan = w->tangible_get(LS, tanobj);
+    Tangible *tan = w->tangible_get(LS, tanobj, false);
     int64_t id = w->alloc_id_predictable();
     AnimStep step;
     step.configure(kp, tan->anim_queue_.back());
@@ -82,7 +82,7 @@ LuaDefine(tangible_setclass, "tan,class",
     LuaVar classtab, mt;
     LuaStack LS(L, tanobj, classname, classtab, mt);
     World *w = World::fetch_global_pointer(L);
-    w->tangible_get(LS, tanobj);
+    w->tangible_get(LS, tanobj, false);
     eng::string err = LS.getclass(classtab, classname);
     if (err != "") {
         luaL_error(L, "%s", err.c_str());
@@ -101,7 +101,7 @@ LuaDefine(tangible_getclass, "tan",
     LuaRet classname;
     LuaStack LS(L, tanobj, mt, classtab, classname);
     World *w = World::fetch_global_pointer(L);
-    w->tangible_get(LS, tanobj);
+    w->tangible_get(LS, tanobj, false);
     LS.getmetatable(mt, tanobj);
     LS.rawget(classtab, mt, "__index");
     eng::string name = LS.classname(classtab);
@@ -120,8 +120,10 @@ LuaDefine(tangible_delete, "tan",
     LuaArg tanobj;
     LuaStack LS(L, tanobj);
     World *w = World::fetch_global_pointer(L);
-    Tangible *tan = w->tangible_get(LS, tanobj);
+    Tangible *tan = w->tangible_get(LS, tanobj, true);
-    assert(tan != nullptr); // this should be checked above.
+    if (tan == nullptr) {
+        return LS.result();
+    }
     if (tan->is_an_actor()) {
         luaL_error(L, "Cannot delete a player using tangible.delete, use tangible.redirect instead.");
         return 0;
@@ -205,14 +207,14 @@ LuaDefine(tangible_redirect, "tan1,tan2,bulldozetan1",
     LuaStack LS(L, actor1, actor2, bldz);
     World *w = World::fetch_global_pointer(L);
     bool bulldoze = LS.ckboolean(bldz);
-    Tangible *tan1 = w->tangible_get(LS, actor1);
+    Tangible *tan1 = w->tangible_get(LS, actor1, false);
     if (!tan1->is_an_actor()) {
         luaL_error(L, "redirect source is not an actor");
     }
     if (LS.isnil(actor2)) {
         w->redirects_[tan1->id()] = 0;
     } else {
-        Tangible *tan2 = w->tangible_get(LS, actor2);
+        Tangible *tan2 = w->tangible_get(LS, actor2, false);
         tan2->configure_id_pool_for_actor();
         w->redirects_[tan1->id()] = tan2->id();
     }
@@ -268,7 +270,7 @@ LuaDefine(tangible_near, "tan,radius,omit_nowhere,omit_self",
     LuaRet list;
     LuaStack LS(L, ltan, lradius, lomit_nowhere, lomit_self, list);
     World *w = World::fetch_global_pointer(L);
-    Tangible *tan = w->tangible_get(LS, ltan);
+    Tangible *tan = w->tangible_get(LS, ltan, false);
     const AnimStep &aqback = tan->anim_queue_.back();
 
     PlaneScan scan;
@@ -460,13 +462,20 @@ LuaDefine(tangible_start, "tangible,function,arg1,arg2...",
         }
     }
 
+    // Check the entire tangible list for validity.
+    for (int i = 1; ; i++) {
+        LS.rawget(place, tanlist, i);
+        if (LS.isnil(place)) break;
+        w->tangible_get(LS, place, false);
+    }
+
+    // Start threads on all the tangibles.
     for (int i = 1; ; i++) {
         LS.rawget(place, tanlist, i);
         if (LS.isnil(place)) break;
 
         // Confirm that the place is a valid tangible,
         // and get the tangible ID.
-        w->tangible_get(LS, place);
         place_id = LS.tanid(place);
 
         // Get place's metatable and threads table.

luprex/cpp/core/world-core.cpp

@@ -134,14 +134,16 @@ World::TanVector World::tangible_get_all(const IdVector &ids) const {
     return result;
 }
 
-Tangible *World::tangible_get(const LuaStack &LS, LuaSlot tab) {
+Tangible *World::tangible_get(const LuaStack &LS, LuaSlot tab, bool allowdel) {
     int64_t id = LS.tanid(tab);
     if (id == 0) {
         luaL_error(LS.state(), "parameter is not a tangible");
     }
     Tangible *result = tangible_get(id);
+    if (!allowdel) {
         if (result == nullptr) {
-        luaL_error(LS.state(), "parameter is not a tangible");
+            luaL_error(LS.state(), "argument is a deleted tangible, which is not allowed here");
+        }
     }
     return result;
 }
@@ -154,9 +156,9 @@ Tangible *World::tangible_make(lua_State *L, int64_t id, const eng::string &plan
     }
     assert(id != 0);
 
-    LuaVar tangibles, metatab;
+    LuaVar metatab;
     LuaRet database;
-    LuaStack LS(L, tangibles, database, metatab);
+    LuaStack LS(L, database, metatab);
 
     // Create the C++ part of the structure.
     UniqueTangible &t = tangibles_[id];
@@ -167,24 +169,13 @@ Tangible *World::tangible_make(lua_State *L, int64_t id, const eng::string &plan
     t->anim_queue_.clear(plane);
     t->update_plane_item();
     
-    // Create the tangible's database and metatable.
+    // Fetch the tangible's Lua database and metatable.
-    LS.set(database, LuaNewTable);
+    LS.maketan(database, id);
-    LS.set(metatab, LuaNewTable);
+    LS.getmetatable(metatab, database);
-    LS.setmetatable(database, metatab);
 
-    // Mark the tangible using the tabletype field.
+    // Set up the inventory and thread table.
-    LS.settabletype(database, LUA_TT_TANGIBLE);
-    LS.settabletype(metatab, LUA_TT_TANGIBLEMETA);
-
-    // Store the database into the tangibles table.
-    LS.rawget(tangibles, LuaRegistry, "tangibles");
-    LS.rawset(tangibles, id, database);
-
-    // Populate the database and metatable with initial stuff.
     LS.rawset(database, "inventory", LuaNewTable);
-    LS.rawset(metatab, "id", id);
     LS.rawset(metatab, "threads", LuaNewTable);
-    // LS.rawset(metatab, "__metatable", LuaNil);
     
     LS.result();
     if (!pushdb) lua_pop(L, 1);
@@ -193,8 +184,8 @@ Tangible *World::tangible_make(lua_State *L, int64_t id, const eng::string &plan
 
 void World::tangible_delete(int64_t id) {
     lua_State *L = state();
-    LuaVar tangibles, database;
+    LuaVar tangibles, database, metatab;
-    LuaStack LS(L, tangibles, database);
+    LuaStack LS(L, tangibles, database, metatab);
 
     // Fetch the C++ side of the tangible.
     auto iter = tangibles_.find(id);
@@ -204,16 +195,17 @@ void World::tangible_delete(int64_t id) {
     }
 
     // Fetch the lua side of the tangible.
-    LS.rawget(tangibles, LuaRegistry, "tangibles");
+    LS.maketan(database, id);
-    LS.rawget(database, tangibles, id);
     assert(LS.istable(database));
+    LS.getmetatable(metatab, database);
 
-    // Clear out the database.
+    // Clear out the database and the metatable.
-    LS.cleartable(database, true);
+    LS.cleartable(database, false);
-    LS.settabletype(database, LUA_TT_DEADTANGIBLE);
+    LS.cleartable(metatab, true);
 
-    // Remove the lua portion from the tangibles table.
+    // Now put the bare minimum info back into the metatable.
-    LS.rawset(tangibles, id, LuaNil);
+    LS.rawset(metatab, "id", id);
+    LS.rawset(metatab, "__metatable", false);
 
     // Remove the C++ portion from the tangibles table.
     tangibles_.erase(iter);

luprex/cpp/core/world-difftab.cpp

@@ -304,12 +304,7 @@ static void set_transmitted_value(LuaStack &LS, LuaSlot tangibles, LuaSlot ntmap
     case LUA_TT_TANGIBLE: {
         int64_t id = sb->read_int64();
         DebugLine(dbc) << dbinfo << "tan " << id;
-        LS.rawget(target, tangibles, id);
+        LS.maketan(target, id);
-        if (LS.isnil(target)) {
-            World *w = World::fetch_global_pointer(LS.state());
-            w->tangible_make(LS.state(), id, "nowhere", true);
-            lua_replace(LS.state(), target.index());
-        }
         return;
     }
     case LUA_TT_GLOBALENV: {

luprex/cpp/core/world-diffxmit.cpp

@@ -1,6 +1,7 @@
-#include "world.hpp"
 #include <iostream>
 
+#include "world.hpp"
+
 util::IdVector World::get_visible_union(int64_t actor_id, World *master) {
     return util::sort_union_id_vectors(
         master->get_near(actor_id, RadiusVisibility, true, false, false),
@@ -85,11 +86,13 @@ void World::patch_visible(StreamBuffer *sb, DebugCollector *dbc) {
     }
 }
 
-void World::diff_visible(const util::IdVector &visible, World *master, StreamBuffer *xsb) {
+void World::diff_visible(const util::IdVector &visible, World *master,
+                         StreamBuffer *xsb) {
     StreamBuffer tsb;
 
     // Get the specified tangibles in both models.
-    // Some tangibles may be missing in the master, some may be missing in the sync.
+    // Some tangibles may be missing in the master, some may be missing in the
+    // sync.
     TanVector mvis = master->tangible_get_all(visible);
     TanVector svis = tangible_get_all(visible);
     assert(mvis.size() == svis.size());
@@ -169,11 +172,13 @@ void World::patch_luatabs(StreamBuffer *sb, DebugCollector *dbc) {
     int64_t actor_id = sb->read_int64();
     util::HashValue closehash = sb->read_hashvalue();
     int ncreate = sb->read_int32();
-    util::IdVector closetans = get_near(actor_id, RadiusClose, true, false, true);
+    util::IdVector closetans =
+        get_near(actor_id, RadiusClose, true, false, true);
     assert(closehash == util::hash_id_vector(closetans));
     number_lua_tables(closetans);
     create_new_tables(ncreate);
-    // DebugLine(dbc) << "lua tables: " << nt << " existing " << ncreate << " new";
+    // DebugLine(dbc) << "lua tables: " << nt << " existing " << ncreate << "
+    // new";
     patch_tangible_databases(sb, dbc);
     patch_numbered_tables(sb, dbc);
     unnumber_lua_tables();
@@ -183,7 +188,8 @@ void World::diff_luatabs(int64_t actor_id, World *master, StreamBuffer *xsb) {
     StreamBuffer tsb;
 
     // Calculate the set of close tangibles.
-    util::IdVector closetans = master->get_near(actor_id, RadiusClose, true, false, true);
+    util::IdVector closetans =
+        master->get_near(actor_id, RadiusClose, true, false, true);
     assert(get_near(actor_id, RadiusClose, true, false, true) == closetans);
     util::HashValue closehash = util::hash_id_vector(closetans);
 
@@ -249,8 +255,10 @@ void World::diff_tanclass(int64_t actor_id, World *master, StreamBuffer *xsb) {
     MLS.rawget(mtangibles, LuaRegistry, "tangibles");
 
     // Calculate the set of close tangibles.
-    // TODO: we've already calculated this in an earlier function. This is wasteful.
+    // TODO: we've already calculated this in an earlier function. This is
-    util::IdVector closetans = master->get_near(actor_id, RadiusClose, true, false, true);
+    // wasteful.
+    util::IdVector closetans =
+        master->get_near(actor_id, RadiusClose, true, false, true);
 
     tsb.write_int32(0);
     int write_count_after = tsb.total_writes();

luprex/cpp/core/world-testing.cpp

@@ -55,14 +55,11 @@ eng::string World::tangible_pprint(int64_t id) const {
     LS.rawget(tan, tangibles, id);
     eng::ostringstream oss;
     if (LS.istable(tan)) {
-        LS.getmetatable(meta, tan);
-        LS.clearmetatable(tan);
         PrettyPrintOptions opts;
         opts.indent = false;
         pprint(LS, tan, opts, &oss);
-        LS.setmetatable(tan, meta);
     } else {
-        oss << "<no such tangible: " << id << ">";
+        oss << "<no such tangible " << id << ">{}";
     }
     LS.result();
     return oss.str();
@@ -384,7 +381,7 @@ LuaDefine(unittests_world3diffluatab, "", "some unit tests") {
 
     // The data in the master model should now look like this:
     const char *expect_123 =
-        "{ "
+        "<tangible 123>{ "
             "bacon='crispy', "
             "inventory={ gold='wealthy' }, "
             "skills={ "
@@ -393,7 +390,7 @@ LuaDefine(unittests_world3diffluatab, "", "some unit tests") {
             "} "
         "}";
     const char *expect_345 =
-        "{ "
+        "<tangible 345>{ "
             "inventory={ gold='poor' }, "
             "phone='867-5309' "
         "}";

luprex/cpp/core/world.hpp

@@ -137,17 +137,21 @@ public:
 
     // Get a pointer to the specified tangible.
     //
-    // If there's no such tangible, returns nullptr.
+    // If there's no such tangible, or if the tangible is deleted,
+    // returns nullptr.
     //
     Tangible *tangible_get(int64_t id);
     const Tangible *tangible_get(int64_t id) const;
 
     // Get a pointer to the specified tangible.
     //
-    // The value on the lua stack should be a valid lua tangible.  If not,
+    // The value on the lua stack should be a lua tangible.
-    // a lua error is generated.
     //
-    Tangible *tangible_get(const LuaStack &LS, LuaSlot slot);
+    // If the 'allowdel' flag is true, then it is valid to pass in
+    // a deleted tangible.  In that case, this function returns nullptr,
+    // but this is not a Lua error.
+    //
+    Tangible *tangible_get(const LuaStack &LS, LuaSlot slot, bool allowdel);
     
     // Get pointers to many tangibles.
     //