Remove ECSEmscripten as Emscripten version is now supported in LDC (+fix compile scripts)

Fix crash in commit() when all components were removed from entity

Closes #2

See merge request Mergul/bubel-ecs!27

.gitlab-ci.yml

@@ -56,7 +56,7 @@ coverage_test_dmd:
         - mkdir reports
         - binaries/dmd_unittest_cov
     after_script:
-        - bash <(curl -s https://codecov.io/bash) -s reports -t 1a0c0169-a721-4085-8252-fed4755dcd8c
+        - bash <(curl -s https://codecov.io/bash) -s reports -t df87b1d8-85f4-4584-96e3-1315d27ec2c5
 
 wasm:
     stage: build_wasm

README.md

@@ -10,6 +10,13 @@ Bubel ECS was tested on Linux, Windows, Android and WASM.
 
 **Currently library is in beta stage so some significant API changes can appear.**
 
+Package is available on [DUB package repository](https://code.dlang.org/packages/bubel-ecs). Usage:
+```
+    "dependencies": {
+        "bubel-ecs": "~>0.1.1"
+    }
+```
+
 ## Design
 
 For core information about Entity-Component-System architectural pattern please read definition described at [Wikipedia](https://en.wikipedia.org/wiki/Entity_component_system).

compile_wasm.py

@@ -13,7 +13,7 @@ def compile(sources, output):
                     if file_extension == '.d' and filename != 'package':
                         files.append(os.path.join(r, file))
 
-    ldc_cmd = 'ldc2 ' + shared_flags + ldc_flags + '-oq -mtriple=wasm32-unknown-unknown-wasm -betterC --output-bc --od=.bc --singleobj --checkaction=C --of=' + output + ' '
+    ldc_cmd = 'ldc2 ' + shared_flags + ldc_flags + '-oq -mtriple=wasm32-unknown-emscripten -betterC --output-bc --od=.bc --singleobj --checkaction=C --of=' + output + ' '
 
     for path in sources:
         ldc_cmd += '-I' + path + ' '
@@ -33,7 +33,7 @@ def compile(sources, output):
 shared_flags = ''
 clean = 0
 emc_flags = ''
-ldc_flags = '--d-version=ECSEmscripten '
+ldc_flags = ''
 import_paths = ['source','tests']
 build_tests = 0
 

demos/compile_wasm.py

@@ -1,7 +1,6 @@
 import os
 import ntpath
 import sys
-import imp
 
 def compile(sources, output):
     files = []
@@ -14,7 +13,7 @@ def compile(sources, output):
                     if file_extension == '.d' and filename != 'package':
                         files.append(os.path.join(r, file))
 
-    ldc_cmd = compiler + shared_flags + ldc_flags + '-oq -mtriple=wasm32-unknown-unknown-wasm -betterC --output-bc --od=.bc --singleobj --checkaction=C --of=' + output + ' '
+    ldc_cmd = compiler + shared_flags + ldc_flags + '-oq -mtriple=wasm32-unknown-emscripten -betterC --output-bc --od=.bc --singleobj --checkaction=C --of=' + output + ' '
 
     for path in sources:
         ldc_cmd += '-I' + path + ' '
@@ -41,7 +40,7 @@ only_bc = 0
 multi = 0
 sources = ['tests', 'source']
 emc_flags = '-s USE_SDL=2 -s USE_SDL_IMAGE=2 -s SDL2_IMAGE_FORMATS="[\'png\']" '
-ldc_flags = '--d-version=ECSEmscripten --d-version=SDL_209 --d-version=BindSDL_Static --d-version=BindSDL_Image --d-version=MM_USE_POSIX_THREADS '
+ldc_flags = '--d-version=SDL_209 --d-version=BindSDL_Static --d-version=BindSDL_Image --d-version=MM_USE_POSIX_THREADS '
 import_paths = ['external/sources', 'external/imports', 'external/wasm_imports', '../source', 'utils/source', 'simple/source']
 
 for arg in sys.argv[1:]:
@@ -121,8 +120,9 @@ emcc_cmd += 'demo.bc '
 
 os.system("mkdir build")
 
-emscripten = imp.load_source('', os.path.expanduser("~") + '/.emscripten')
+# emscripten = imp.load_source('', os.path.expanduser("~") + '/.emscripten')
-pack_cmd = emscripten.EMSCRIPTEN_ROOT + '/tools/file_packager.py build/assets.data --preload assets --js-output=build/assets.js'
+# pack_cmd = emscripten.EMSCRIPTEN_ROOT + '/tools/file_packager.py build/assets.data --preload assets --js-output=build/assets.js'
+pack_cmd = os.path.expandvars('$EMSDK/upstream/emscripten') + '/tools/file_packager.py build/assets.data --preload assets --js-output=build/assets.js'
 print('Packafing files: ' + pack_cmd)
 
 os.system(pack_cmd)

demos/meson.build

@@ -27,7 +27,7 @@ executable('BubelECSDemos', [demos_src, external_src],
 		bindbc_loader_dep,
 		bindbc_sdl_dep,
 		cimgui_dep,
-		decs_dep,
+		bubel_ecs_dep,
 		ecs_utils_dep,
 		sdl2_dep,
 		sdl2_image_dep,

demos/utils/meson.build

@@ -5,12 +5,12 @@ subdir('source/ecs_utils')
 utils_inc = include_directories('source/')
 
 # Dependencies
-ecs_utils_lib = library('ecs_utils', utils_src,
+ecs_utils_lib = library('ECSUtils', utils_src,
 	include_directories : [demos_inc, external_inc, utils_inc],
 	link_args : link_args, 
 	d_module_versions : versions,
 	dependencies : [
-		decs_dep,
+		bubel_ecs_dep,
 		bindbc_loader_dep,
 		bindbc_sdl_dep,
 	]

dub.json

@@ -5,7 +5,7 @@
 		"Michał Masiukiewicz", "Dawid Masiukiewicz"
 	],
 	"description": "Dynamic Entity Component System",
-	"copyright": "Copyright © 2018-2019, Michał Masiukiewicz, Dawid Masiukiewicz",
+	"copyright": "Copyright © 2018-2023, Michał Masiukiewicz, Dawid Masiukiewicz",
 	"license": "BSD 3-clause",
 	"sourcePaths" : ["source\/"],
 	"excludedSourceFiles":[
@@ -63,7 +63,7 @@
 			],
 			"dflags": [
 				"-unittest",
-				"-cov"
+				"-cov=ctfe"
 			]
 		},
 		{

meson.build

@@ -58,7 +58,7 @@ threads_dep = dependency('threads')
 d_versions = []
 deps = []
 if host_machine.cpu_family() == 'wasm32'
-	d_versions += 'ECSEmscripten'
+
 else
 	# meson incorectly adds "-s USE_PTHREADS=1" to ldc2 invocation whe pthreads is added as dependency
 	# add it for non wasm builds

source/bubel/ecs/atomic.d

@@ -4,129 +4,10 @@ It's internal code. Can be used for atomics if emscripten backend will be used.
 This module contain atomic operations which include support for emscripten atomics functions.
 Emscripten functions are contained in API similar to druntime.
 
-Copyright: Copyright © 2018-2019, Dawid Masiukiewicz, Michał Masiukiewicz
+Copyright: Copyright © 2018-2023, Dawid Masiukiewicz, Michał Masiukiewicz
 License: BSD 3-clause, see LICENSE file in project root folder.
 */
 module bubel.ecs.atomic;
 
-version (Emscripten) version = ECSEmscripten;
+public import core.atomic;
 
-version (ECSEmscripten)
-{
-    import std.traits;
-
-    enum MemoryOrder
-    {
-        acq,
-        acq_rel,
-        raw,
-        rel,
-        seq
-    }
-
-    extern (C) ubyte emscripten_atomic_cas_u8(void* addr, ubyte oldVal, ubyte newVal) @nogc nothrow pure;
-    extern (C) ushort emscripten_atomic_cas_u16(void* addr, ushort oldVal, ushort newVal) @nogc nothrow pure;
-    extern (C) uint emscripten_atomic_cas_u32(void* addr, uint oldVal, uint newVal) @nogc nothrow pure;
-
-    extern (C) ubyte emscripten_atomic_load_u8(const void* addr) @nogc nothrow pure;
-    extern (C) ushort emscripten_atomic_load_u16(const void* addr) @nogc nothrow pure;
-    extern (C) uint emscripten_atomic_load_u32(const void* addr) @nogc nothrow pure;
-
-    extern (C) ubyte emscripten_atomic_store_u8(void* addr, ubyte val) @nogc nothrow pure;
-    extern (C) ushort emscripten_atomic_store_u16(void* addr, ushort val) @nogc nothrow pure;
-    extern (C) uint emscripten_atomic_store_u32(void* addr, uint val) @nogc nothrow pure;
-
-    extern (C) ubyte emscripten_atomic_add_u8(void* addr, ubyte val) @nogc nothrow pure;
-    extern (C) ushort emscripten_atomic_add_u16(void* addr, ushort val) @nogc nothrow pure;
-    extern (C) uint emscripten_atomic_add_u32(void* addr, uint val) @nogc nothrow pure;
-
-    extern (C) ubyte emscripten_atomic_sub_u8(void* addr, ubyte val) @nogc nothrow pure;
-    extern (C) ushort emscripten_atomic_sub_u16(void* addr, ushort val) @nogc nothrow pure;
-    extern (C) uint emscripten_atomic_sub_u32(void* addr, uint val) @nogc nothrow pure;
-
-    public pure nothrow @nogc Unqual!T atomicOp(string op, T, V1)(ref shared T val, V1 mod)
-    {
-        static if (op == "+=")
-        {
-            static if (is(T == byte) || is(T == ubyte))
-                return cast(Unqual!T)(emscripten_atomic_add_u8(cast(void*)&val,
-                        cast(Unqual!T) mod) + 1);
-            else static if (is(T == short) || is(T == ushort))
-                return cast(Unqual!T)(emscripten_atomic_add_u16(cast(void*)&val,
-                        cast(Unqual!T) mod) + 1);
-            else static if (is(T == int) || is(T == uint))
-                return cast(Unqual!T)(emscripten_atomic_add_u32(cast(void*)&val,
-                        cast(Unqual!T) mod) + 1);
-            else
-                static assert(0);
-        }
-        else static if (op == "-=")
-        {
-            static if (is(T == byte) || is(T == ubyte))
-                return cast(Unqual!T)(emscripten_atomic_sub_u8(cast(void*)&val,
-                        cast(Unqual!T) mod) - 1);
-            else static if (is(T == short) || is(T == ushort))
-                return cast(Unqual!T)(emscripten_atomic_sub_u16(cast(void*)&val,
-                        cast(Unqual!T) mod) - 1);
-            else static if (is(T == int) || is(T == uint))
-                return cast(Unqual!T)(emscripten_atomic_sub_u32(cast(void*)&val,
-                        cast(Unqual!T) mod) - 1);
-            else
-                static assert(0);
-        }
-    }
-
-    public pure nothrow @nogc @trusted void atomicStore(MemoryOrder ms = MemoryOrder.seq, T, V)(ref T val,
-            V newval)
-    {
-        alias UT = Unqual!T;
-        static if (is(UT == bool) || is(UT == byte) || is(UT == ubyte))
-            emscripten_atomic_store_u8(cast(void*)&val, cast(UT) newval);
-        else static if (is(UT == short) || is(UT == ushort))
-            emscripten_atomic_store_u16(cast(void*)&val, cast(UT) newval);
-        else static if (is(UT == int) || is(UT == uint))
-            emscripten_atomic_store_u32(cast(void*)&val, cast(UT) newval);
-        else
-            static assert(0);
-    }
-
-    public pure nothrow @nogc @trusted T atomicLoad(MemoryOrder ms = MemoryOrder.seq, T)(
-            ref const T val)
-    {
-        alias UT = Unqual!T;
-        static if (is(UT == bool))
-            return emscripten_atomic_load_u8(cast(const void*)&val) != 0;
-        else static if (is(UT == byte) || is(UT == ubyte))
-            return emscripten_atomic_load_u8(cast(const void*)&val);
-        else static if (is(UT == short) || is(UT == ushort))
-            return emscripten_atomic_load_u16(cast(const void*)&val);
-        else static if (is(UT == int) || is(UT == uint))
-            return emscripten_atomic_load_u32(cast(const void*)&val);
-        else
-            static assert(0);
-    }
-
-    public pure nothrow @nogc @trusted bool cas(MemoryOrder succ = MemoryOrder.seq,
-            MemoryOrder fail = MemoryOrder.seq, T, V1, V2)(T* here, V1 ifThis, V2 writeThis)
-    {
-        alias UT = Unqual!T;
-        static if (is(UT == bool))
-            return emscripten_atomic_cas_u8(cast(void*) here,
-                    cast(Unqual!T) ifThis, cast(Unqual!T) writeThis) == ifThis;
-        else static if (is(UT == byte) || is(UT == ubyte))
-            return emscripten_atomic_cas_u8(cast(void*) here,
-                    cast(Unqual!T) ifThis, cast(Unqual!T) writeThis) == ifThis;
-        else static if (is(UT == short) || is(UT == ushort))
-            return emscripten_atomic_cas_u16(cast(void*) here,
-                    cast(Unqual!T) ifThis, cast(Unqual!T) writeThis) == ifThis;
-        else static if (is(UT == int) || is(UT == uint))
-            return emscripten_atomic_cas_u32(cast(void*) here,
-                    cast(Unqual!T) ifThis, cast(Unqual!T) writeThis) == ifThis;
-        else
-            static assert(0);
-    }
-}
-else
-{
-    public import core.atomic;
-}

source/bubel/ecs/attributes.d

@@ -17,7 +17,7 @@ Struct EntitiesData
 }
 ---
 
-Copyright: Copyright © 2018-2019, Dawid Masiukiewicz, Michał Masiukiewicz
+Copyright: Copyright © 2018-2023, Dawid Masiukiewicz, Michał Masiukiewicz
 License: BSD 3-clause, see LICENSE file in project root folder.
 */
 module bubel.ecs.attributes;

source/bubel/ecs/block_allocator.d

@@ -3,7 +3,7 @@ It's internal code.
 
 Module contain memory allocator.
 
-Copyright: Copyright © 2018-2019, Dawid Masiukiewicz, Michał Masiukiewicz
+Copyright: Copyright © 2018-2023, Dawid Masiukiewicz, Michał Masiukiewicz
 License: BSD 3-clause, see LICENSE file in project root folder.
 */
 module bubel.ecs.block_allocator;

source/bubel/ecs/core.d

@@ -67,7 +67,7 @@ Struct System1
 }
 ---
 
-Copyright: Copyright © 2018-2019, Dawid Masiukiewicz, Michał Masiukiewicz
+Copyright: Copyright © 2018-2023, Dawid Masiukiewicz, Michał Masiukiewicz
 License: BSD 3-clause, see LICENSE file in project root folder.
 */
 module bubel.ecs.core;

source/bubel/ecs/entity.d

@@ -1,7 +1,7 @@
 /************************************************************************************************************************
 Entity module.
 
-Copyright: Copyright © 2018-2019, Dawid Masiukiewicz, Michał Masiukiewicz
+Copyright: Copyright © 2018-2023, Dawid Masiukiewicz, Michał Masiukiewicz
 License: BSD 3-clause, see LICENSE file in project root folder.
 */
 module bubel.ecs.entity;
@@ -44,7 +44,7 @@ struct Entity
         return cast(T*)getComponent(becsID!T);
     }
 
-    void* getComponent(ushort component_id) const
+    export void* getComponent(ushort component_id) const
     {
         EntityManager.EntitiesBlock* block = gEntityManager.getMetaData(&this);
         EntityManager.EntityInfo* info = block.type_info;
@@ -54,7 +54,7 @@ struct Entity
         return (cast(void*)block + info.deltas[component_id] + block.entityIndex(&this) * gEntityManager.components[component_id].size);
     }
 
-    bool hasComponent(ushort component_id) const
+    export bool hasComponent(ushort component_id) const
     {
         EntityManager.EntitiesBlock* block = gEntityManager.getMetaData(&this);
         EntityManager.EntityInfo* info = block.type_info;
@@ -62,7 +62,7 @@ struct Entity
         return true;
     }
 
-    EntityMeta getMeta() const
+    export EntityMeta getMeta() const
     {
         EntityMeta meta;
         meta.block = gEntityManager.getMetaData(&this);
@@ -85,7 +85,7 @@ struct EntityMeta
         return cast(T*)getComponent(becsID!T);
     }
     
-    void* getComponent(ushort component_id) const
+    export void* getComponent(ushort component_id) const
     {
         const (EntityManager.EntityInfo)* info = block.type_info;
 
@@ -95,7 +95,7 @@ struct EntityMeta
         return (cast(void*)block + info.deltas[component_id] + index * gEntityManager.components[component_id].size);
     }
 
-    bool hasComponent(ushort component_id) const
+    export bool hasComponent(ushort component_id) const
     {
         const EntityManager.EntityInfo* info = block.type_info;
         if (component_id >= info.deltas.length || info.deltas[component_id] == 0)return false;
@@ -133,7 +133,7 @@ export struct EntityTemplate
     /************************************************************************************************************************
     Get specified component. If component doesn't exist function return null. Returned pointer is valid during EntityTemplate lifetime.
     */
-    void* getComponent(ushort component_id) const nothrow @nogc
+    export void* getComponent(ushort component_id) const nothrow @nogc
     {
         if(component_id >= info.tmpl_deltas.length || info.tmpl_deltas[component_id] == ushort.max)return null;
         return cast(void*)(entity_data.ptr + info.tmpl_deltas[component_id]);

source/bubel/ecs/events.d

@@ -1,5 +1,5 @@
 /************************************************************************************************************************
-Copyright: Copyright © 2018-2019, Dawid Masiukiewicz, Michał Masiukiewicz
+Copyright: Copyright © 2018-2023, Dawid Masiukiewicz, Michał Masiukiewicz
 License: BSD 3-clause, see LICENSE file in project root folder.
 */
 module bubel.ecs.events;

source/bubel/ecs/hash_map.d

@@ -1,5 +1,5 @@
 /************************************************************************************************************************
-Copyright: Copyright © 2018-2019, Dawid Masiukiewicz, Michał Masiukiewicz
+Copyright: Copyright © 2018-2023, Dawid Masiukiewicz, Michał Masiukiewicz
 License: BSD 3-clause, see LICENSE file in project root folder.
 */
 module bubel.ecs.hash_map;
@@ -28,7 +28,7 @@ export ulong defaultHashFunc(T)(auto ref T t) nothrow @nogc
 	}
 }
 
-ulong hash(byte[] array) nothrow @nogc
+export ulong hash(byte[] array) nothrow @nogc
 {
 	ulong hash = 0;
 
@@ -341,7 +341,7 @@ nothrow:
 		int result;
 		foreach (ref Key k; this)
 		{
-			result = (cast(int delegate(ref Key k) nothrow)dg)(k);
+			result = (cast(int delegate(ref Key k) nothrow @nogc)dg)(k);
 			if (result)
 				break;
 		}
@@ -353,7 +353,7 @@ nothrow:
 		int result;
 		foreach (ref Value v; this)
 		{
-			result = (cast(int delegate(ref Value v) nothrow)dg)(v);
+			result = (cast(int delegate(ref Value v) nothrow @nogc)dg)(v);
 			if (result)
 				break;
 		}
@@ -365,7 +365,7 @@ nothrow:
 		int result;
 		foreach (ref Key k, ref Value v; this)
 		{
-			result = (cast(int delegate(ref Key k, ref Value v) nothrow)dg)(k, v);
+			result = (cast(int delegate(ref Key k, ref Value v) nothrow @nogc)dg)(k, v);
 			if (result)
 				break;
 		}

source/bubel/ecs/id_manager.d

@@ -1,5 +1,5 @@
 /************************************************************************************************************************
-Copyright: Copyright © 2018-2019, Dawid Masiukiewicz, Michał Masiukiewicz
+Copyright: Copyright © 2018-2023, Dawid Masiukiewicz, Michał Masiukiewicz
 License: BSD 3-clause, see LICENSE file in project root folder.
 */
 module bubel.ecs.id_manager;

source/bubel/ecs/package.d

@@ -1,5 +1,5 @@
 /************************************************************************************************************************
-Copyright: Copyright © 2018-2019, Dawid Masiukiewicz, Michał Masiukiewicz
+Copyright: Copyright © 2018-2023, Dawid Masiukiewicz, Michał Masiukiewicz
 License: BSD 3-clause, see LICENSE file in project root folder.
 */
 module ecs;

source/bubel/ecs/simple_vector.d

@@ -1,5 +1,5 @@
 /************************************************************************************************************************
-Copyright: Copyright © 2018-2019, Dawid Masiukiewicz, Michał Masiukiewicz
+Copyright: Copyright © 2018-2023, Dawid Masiukiewicz, Michał Masiukiewicz
 License: BSD 3-clause, see LICENSE file in project root folder.
 */
 module bubel.ecs.simple_vector;

source/bubel/ecs/std.d

@@ -2,16 +2,14 @@
 It's internal code!
 This module contain implementation of standard functionality.
 
-Copyright: Copyright © 2018-2019, Dawid Masiukiewicz, Michał Masiukiewicz
+Copyright: Copyright © 2018-2023, Dawid Masiukiewicz, Michał Masiukiewicz
 License: BSD 3-clause, see LICENSE file in project root folder.
 */
 module bubel.ecs.std;
 
-version (Emscripten) version = ECSEmscripten;
-
 import std.traits;
 
-version (ECSEmscripten)
+version (Emscripten)
 {
     extern (C) struct pthread_mutex_t
     {
@@ -29,10 +27,6 @@ version (ECSEmscripten)
 
     extern (C) int memcmp(const void* s1, const void* s2, size_t size);
     extern (C) void exit(int status) nothrow @nogc;
-    extern (C) void __assert(const(char)* msg, const(char)* file, uint line)
-    {
-        exit(-20);
-    }
 
     extern (C) void free(void*) @nogc nothrow @system;
     extern (C) void* malloc(size_t size) @nogc nothrow @system;
@@ -60,7 +54,7 @@ else
     public import core.stdc.stdlib : qsort;
 }
 
-version (ECSEmscripten)
+version (Emscripten)
 {
 }
 else version (Windows)
@@ -89,7 +83,7 @@ else version (Posix)
     import core.sys.posix.stdlib : posix_memalign;
 }
 
-version (ECSEmscripten)
+version (Emscripten)
 {
     private const uint max_alloca = 10000;
     private __gshared byte[max_alloca] alloca_array;
@@ -294,7 +288,7 @@ static struct Mallocator
             posix_memalign(&ret, alignment, length); //ret = aligned_alloc(alignment, length);
         else version (Windows)
             ret = _aligned_malloc(length, alignment);
-        else version (ECSEmscripten)
+        else version (Emscripten)
             posix_memalign(&ret, alignment, length); //malloc(length);
         else
             static assert(0, "Unimplemented platform!");
@@ -341,7 +335,7 @@ static struct Mallocator
             free(cast(void*) object);
         else version (Windows)
             _aligned_free(cast(void*) object);
-        else version (ECSEmscripten)
+        else version (Emscripten)
             free(cast(void*) object);
         else
             static assert(0, "Unimplemented platform!");
@@ -351,7 +345,7 @@ static struct Mallocator
 struct Mutex
 {
 
-    version (ECSEmscripten)
+    version (Emscripten)
     {
         void initialize() nothrow @nogc
         {

source/bubel/ecs/system.d

@@ -1,7 +1,7 @@
 /************************************************************************************************************************
 System module.
 
-Copyright: Copyright © 2018-2019, Dawid Masiukiewicz, Michał Masiukiewicz
+Copyright: Copyright © 2018-2023, Dawid Masiukiewicz, Michał Masiukiewicz
 License: BSD 3-clause, see LICENSE file in project root folder.
 */
 module bubel.ecs.system;
@@ -13,14 +13,14 @@ import bubel.ecs.manager;
 System contain data required to proper glue EntityManager with Systems.
 System callbacks:
 $(LIST
-    * void onUpdate(EntitesData);
+    * void onUpdate(EntitiesData);
     * void onEnable() - called inside system.enable() function
     * void onDisable() - called inside system.disable() function
     * bool onBegin() - called inside manager.begin()
     * void onEnd() - called inside manager.end()
     * void onCreate() - called after registration inside registerSystem function
     * void onDestroy() - called during re-registration and inside manager destructor
-    * void onAddEntity(EntitesData) - called for every entity which are assigned to system (by adding new entity or changing its components)
+    * void onAddEntity(EntitiesData) - called for every entity which are assigned to system (by adding new entity or changing its components)
     * void onRemoveEntity(EntitiesData) - called for every entity removed from system update process
     * void onChangeEntity(EntitiesData) - called for every entity which components are changed but it was previously assigned to system
     * void handleEvent(Entity*, Event) - called for every event supported by system
@@ -89,38 +89,100 @@ struct System
         return cast(const(char)[]) m_name;
     }
 
+    /************************************************************************************************************************
+    Return false if system was unregistered, true otherwise.
+    */
+    export bool isAlive() nothrow @nogc
+    {
+        return m_system_pointer != null;
+    }
+
+    /************************************************************************************************************************
+    Return pointer to user side system object
+    */
+    export void* ptr() nothrow @nogc
+    {
+        return m_system_pointer;
+    }
+
 package:
 
-    void destroy()
+    ///destory system. Dispose all data
+    export void destroy() nothrow @nogc
+    {
+        import bubel.ecs.std : Mallocator;
+
+        destroySystemData();
+
+        if (m_name)
+        {
+            Mallocator.dispose(m_name);
+            m_name = null;
+        }
+    }
+
+    ///destroy all system data but keeps name which is used for case of system re-registration
+    void destroySystemData() nothrow @nogc
     {
         import bubel.ecs.std : Mallocator;
         disable();
         if (m_destroy)
-            (cast(void function(void*)) m_destroy)(m_system_pointer);
+        {
+            (cast(void function(void*) nothrow @nogc) m_destroy)(m_system_pointer);
+            m_destroy = null;
+        }
 
-        if (m_name)
-            Mallocator.dispose(m_name);
         if (m_components)
+        {
             Mallocator.dispose(m_components);
+            m_components = null;
+        }
         if (m_excluded_components)
+        {
             Mallocator.dispose(m_excluded_components);
+            m_excluded_components = null;
+        }
         if (m_optional_components)
+        {
             Mallocator.dispose(m_optional_components);
+            m_optional_components = null;
+        }
         if (jobs)
+        {
             Mallocator.dispose(jobs);
+            jobs = null;
+        }
         if (m_read_only_components)
+        {
             Mallocator.dispose(m_read_only_components);
+            m_read_only_components = null;
+        }
         if (m_writable_components)
+        {
             Mallocator.dispose(m_writable_components);
+            m_writable_components = null;
+        }
         if (m_readonly_dependencies)
+        {
             Mallocator.dispose(m_readonly_dependencies);
+            m_readonly_dependencies = null;
+        }
         if (m_writable_dependencies)
+        {
             Mallocator.dispose(m_writable_dependencies);
+            m_writable_dependencies = null;
+        }
         if (m_event_callers)
+        {
             Mallocator.dispose(m_event_callers);
+            m_event_callers = null;
+        }
 
         if (m_system_pointer)
+        {
             Mallocator.dispose(m_system_pointer);
+            m_system_pointer = null;
+        }
     }
 
     struct EventCaller

source/bubel/ecs/traits.d

@@ -1,5 +1,5 @@
 /************************************************************************************************************************
-Copyright: Copyright © 2018-2019, Dawid Masiukiewicz, Michał Masiukiewicz
+Copyright: Copyright © 2018-2023, Dawid Masiukiewicz, Michał Masiukiewicz
 License: BSD 3-clause, see LICENSE file in project root folder.
 */
 module bubel.ecs.traits;

source/bubel/ecs/vector.d

@@ -1,5 +1,5 @@
 /************************************************************************************************************************
-Copyright: Copyright © 2018-2019, Dawid Masiukiewicz, Michał Masiukiewicz
+Copyright: Copyright © 2018-2023, Dawid Masiukiewicz, Michał Masiukiewicz
 License: BSD 3-clause, see LICENSE file in project root folder.
 */
 module bubel.ecs.vector;

tests/basic.d

@@ -113,6 +113,31 @@ struct EmptySystem
     int count = 0;
 }
 
+struct EntityCounterSystem
+{
+    mixin ECS.System!1;
+
+    struct EntitiesData
+    {
+        int thread_id;
+        uint length;
+        Entity[] entity;
+    }
+
+    bool onBegin()
+    {
+        count = 0;
+        return true;
+    }
+
+    void onUpdate(EntitiesData data)
+    {
+        count += data.length;
+    }
+
+    int count = 0;
+}
+
 void beforeEveryTest()
 {
     becsID!CUnregistered = ushort.max;
@@ -243,7 +268,82 @@ unittest
     gEntityManager.commit();
     entity3 = gEntityManager.getEntity(id);
     assert(!entity3.getComponent!CUnregistered);
+}
 
+@("AddEmptyEntity")
+unittest
+{
+    struct OnAddRemoveChangeCounter
+    {
+        mixin ECS.System!1;
+
+        struct EntitiesData
+        {
+            int thread_id;
+            uint length;
+            Entity[] entity;
+        }
+
+        void onAddEntity(EntitiesData data)
+        {
+            add += data.length;
+        }
+        
+        void onRemoveEntity(EntitiesData data)
+        {
+            assert(0, "It's impossible to remove entity from being updated by system which accept empty entity");
+        }
+
+        int add = 0;
+    }
+
+    gEntityManager.beginRegister();
+
+    gEntityManager.registerSystem!EntityCounterSystem(0);
+    gEntityManager.registerSystem!OnAddRemoveChangeCounter(1);
+
+    gEntityManager.endRegister();
+
+    CLong long_component = CLong(3);
+
+    Entity* entity = null;
+    EntityID entity_id = gEntityManager.addEntity(null).id;
+
+    EntityCounterSystem* system = gEntityManager.getSystem!EntityCounterSystem;
+    assert(system !is null);
+    assert(system.count == 0);
+
+    OnAddRemoveChangeCounter* add_remove_change_system = gEntityManager.getSystem!OnAddRemoveChangeCounter;
+    assert(add_remove_change_system !is null);
+    assert(add_remove_change_system.add == 0);
+
+    gEntityManager.commit();
+    assert(add_remove_change_system.add == 1);
+
+    entity = gEntityManager.getEntity(entity_id);
+    assert(!entity.hasComponent(becsID!CLong));
+    assert(entity.getComponent(becsID!CLong) is null);
+    
+
+    gEntityManager.begin();
+    gEntityManager.update();
+    assert(system.count == 1);
+    gEntityManager.end();
+
+    gEntityManager.addEntityCopy(entity_id);
+    gEntityManager.addEntityCopy(entity_id);
+    gEntityManager.addComponents(entity_id, [ComponentRef(&long_component, becsID(long_component))].staticArray);
+    gEntityManager.commit();
+    assert(add_remove_change_system.add == 3, "onAddEntity missed");
+
+    entity = gEntityManager.getEntity(entity_id);
+    assert(entity.hasComponent(becsID!CLong));
+    assert(*entity.getComponent!CLong == 3);
+
+    gEntityManager.begin();
+    gEntityManager.update();
+    assert(system.count == 3);
+    gEntityManager.end();
 }
 
 //allocate templates

tests/bugs.d

@@ -142,5 +142,34 @@ unittest
     gEntityManager.update();
     gEntityManager.end();
 
+    gEntityManager.destroy();
+}
+
+@("2-empty-entity-crash")
+unittest
+{
+    
+    gEntityManager.initialize(0);
+
+    gEntityManager.beginRegister();
+
+    gEntityManager.registerComponent!CInt;
+    gEntityManager.registerComponent!CFloat;
+
+    gEntityManager.endRegister();
+
+
+    EntityTemplate* tmpl = gEntityManager.allocateTemplate([becsID!CInt, becsID!CFloat].staticArray);
+    scope(exit) gEntityManager.freeTemplate(tmpl);
+
+    EntityID id = gEntityManager.addEntity(tmpl).id;
+    // EntityID id2 = gEntityManager.addEntity().id;
+
+    gEntityManager.commit();
+
+    gEntityManager.removeComponents(id, [becsID!CInt, becsID!CFloat].staticArray);
+
+    gEntityManager.commit();
+
     gEntityManager.destroy();
 }