Replace IAllocator with reference counted struct

changelog/std-experimental-allocator-rciallocator.dd

@@ -0,0 +1,19 @@
+Replace `std.experimental.allocator.IAllocator` with `std.experimental.allocator.RCIAllocator`
+
+$(B Motivation):
+
+Keep track of references to allocators so they don't escape, dangle,
+and cause undefined behavior.
+
+From now on, `RCIAllocator` will be used instead of the old `IAllocator`
+interface. $(REF allocatorObject, std, experimental, allocator) can be used to build
+a `RCIAllocator` out of a custom allocator.
+
+------
+import std.experimental.allocator.mallocator : Mallocator;
+
+RCIAllocator a = allocatorObject(Mallocator.instance);
+auto b = a.allocate(100);
+assert(b.length == 100);
+assert(a.deallocate(b));
+------

changelog/std-experimental-allocator-rcisharedallocator.dd

@@ -0,0 +1,23 @@
+Replace `std.experimental.allocator.ISharedAllocator` with `std.experimental.allocator.RCISharedAllocator`
+
+$(B Motivation):
+
+Keep track of references to allocators so they don't escape, dangle,
+and cause undefined behavior.
+
+From now on, `RCISharedAllocator` will be used instead of the old
+`ISharedAllocator` interface.
+$(REF sharedAllocatorObject, std, experimental, allocator)` can be used to build
+a `RCISharedAllocator` out of a custom allocator.
+
+------
+import std.experimental.allocator.building_blocks.free_list : SharedFreeList;
+import std.experimental.allocator.mallocator : Mallocator;
+
+shared SharedFreeList!(Mallocator, chooseAtRuntime, chooseAtRuntime) sharedFL;
+shared RCISharedAllocator sharedFLObj = sharedAllocatorObject(sharedFL);
+
+auto b = sharedFLObj.allocate(100);
+assert(b.length == 100);
+assert(sharedFLObj.deallocate(b));
+------

std/experimental/allocator/building_blocks/affix_allocator.d

@@ -24,7 +24,7 @@ struct AffixAllocator(Allocator, Prefix, Suffix = void)
 {
     import std.algorithm.comparison : min;
     import std.conv : emplace;
-    import std.experimental.allocator : IAllocator, theAllocator;
+    import std.experimental.allocator : RCIAllocator, theAllocator;
     import std.experimental.allocator.common : stateSize, forwardToMember,
         roundUpToMultipleOf, alignedAt, alignDownTo, roundUpToMultipleOf,
         hasStaticallyKnownAlignment;
@@ -69,11 +69,11 @@ struct AffixAllocator(Allocator, Prefix, Suffix = void)
     static if (stateSize!Allocator)
     {
         Allocator _parent;
-        static if (is(Allocator == IAllocator))
+        static if (is(Allocator == RCIAllocator))
         {
             Allocator parent()
             {
-                if (_parent is null) _parent = theAllocator;
+                if (_parent.isNull) _parent = theAllocator;
                 assert(alignment <= _parent.alignment);
                 return _parent;
             }
@@ -376,18 +376,18 @@ struct AffixAllocator(Allocator, Prefix, Suffix = void)
 @system unittest
 {
     import std.experimental.allocator.gc_allocator : GCAllocator;
-    import std.experimental.allocator : theAllocator, IAllocator;
+    import std.experimental.allocator : theAllocator, RCIAllocator;
 
     // One word before and after each allocation.
-    auto A = AffixAllocator!(IAllocator, size_t, size_t)(theAllocator);
+    auto A = AffixAllocator!(RCIAllocator, size_t, size_t)(theAllocator);
     auto a = A.allocate(11);
     A.prefix(a) = 0xCAFE_BABE;
     A.suffix(a) = 0xDEAD_BEEF;
     assert(A.prefix(a) == 0xCAFE_BABE
         && A.suffix(a) == 0xDEAD_BEEF);
 
     // One word before and after each allocation.
-    auto B = AffixAllocator!(IAllocator, size_t, size_t)();
+    auto B = AffixAllocator!(RCIAllocator, size_t, size_t)();
     auto b = B.allocate(11);
     B.prefix(b) = 0xCAFE_BABE;
     B.suffix(b) = 0xDEAD_BEEF;

std/experimental/allocator/common.d

@@ -481,7 +481,7 @@ Forwards each of the methods in `funs` (if defined) to `member`.
 
 version(unittest)
 {
-    import std.experimental.allocator : IAllocator, ISharedAllocator;
+    import std.experimental.allocator : RCIAllocator, RCISharedAllocator;
 
     package void testAllocator(alias make)()
     {
@@ -607,18 +607,18 @@ version(unittest)
          }}
     }
 
-    package void testAllocatorObject(AllocInterface)(AllocInterface a)
-        if (is(AllocInterface : IAllocator)
-            || is (AllocInterface : shared ISharedAllocator))
+    package void testAllocatorObject(RCAllocInterface)(RCAllocInterface a)
+        if (is(RCAllocInterface == RCIAllocator)
+            || is (RCAllocInterface == shared RCISharedAllocator))
     {
         import std.conv : text;
         import std.math : isPowerOf2;
         import std.stdio : writeln, stderr;
         import std.typecons : Ternary;
         scope(failure) stderr.writeln("testAllocatorObject failed for ",
-                AllocInterface.stringof);
+                RCAllocInterface.stringof);
 
-        assert(a);
+        assert(!a.isNull);
 
         // Test alignment
         assert(a.alignment.isPowerOf2);