Add internal allocator functionality to prepare for refactoring in vi…

…be-core.

See vibe-d/vibe-core#383 and vibe-d/vibe.d#2777.

source/vibe/container/internal/utilallocator.d

@@ -15,6 +15,52 @@ public import stdx.allocator.building_blocks.affix_allocator;
 	return s_threadAllocator;
 }
 
+auto makeGCSafe(T, Allocator, A...)(Allocator allocator, A args)
+{
+	import core.memory : GC;
+	import std.traits : hasIndirections;
+
+	auto ret = allocator.make!T(args);
+	static if (is (T == class)) enum tsize = __traits(classInstanceSize, T);
+	else enum tsize = T.sizeof;
+	static if (hasIndirections!T)
+		() @trusted { GC.addRange(cast(void*)ret, tsize, typeid(T)); } ();
+	return ret;
+}
+
+void disposeGCSafe(T, Allocator)(Allocator allocator, T obj)
+{
+	import core.memory : GC;
+	import std.traits : hasIndirections;
+
+	static if (hasIndirections!T)
+		GC.removeRange(cast(void*)obj);
+	allocator.dispose(obj);
+}
+
+void ensureNotInGC(T)(string info = null) nothrow
+{
+	import core.exception : InvalidMemoryOperationError;
+	try
+	{
+		import core.memory : GC;
+		cast(void) GC.malloc(1);
+		return;
+	}
+	catch(InvalidMemoryOperationError e)
+	{
+		import core.stdc.stdio : fprintf, stderr;
+		import core.stdc.stdlib : exit;
+		fprintf(stderr,
+				"Error: clean-up of %s incorrectly depends on destructors called by the GC.\n",
+				T.stringof.ptr);
+		if (info)
+			fprintf(stderr, "Info: %s\n", info.ptr);
+		assert(false);
+	}
+}
+
+
 final class RegionListAllocator(Allocator, bool leak = false) : IAllocator {
 	import vibe.internal.memory_legacy : AllocSize, alignedSize;
 	import std.algorithm.comparison : min, max;
@@ -113,9 +159,9 @@ final class RegionListAllocator(Allocator, bool leak = false) : IAllocator {
 		override Ternary resolveInternalPointer(void* p, ref void[] result) { return Ternary.unknown; }
 	}
 	static if (is(Parameters!(IAllocator.owns)[0] == const(void[]))) {
-	    override Ternary owns(const void[] b) { return Ternary.unknown; }
+		override Ternary owns(const void[] b) { return Ternary.unknown; }
 	} else {
-	    override Ternary owns(void[] b) { return Ternary.unknown; }
+		override Ternary owns(void[] b) { return Ternary.unknown; }
 	}