1 files changed, 169 insertions, 0 deletions
diff --git a/Source/WTF/wtf/BlockPtr.h b/Source/WTF/wtf/BlockPtr.h
new file mode 100644
index 000000000..1b79d4178
--- /dev/null
+++ b/Source/WTF/wtf/BlockPtr.h
@@ -0,0 +1,169 @@
+/*
+ * Copyright (C) 2016 Apple Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
+ * THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#pragma once
+
+#include <Block.h>
+#include <wtf/Assertions.h>
+
+namespace WTF {
+
+extern "C" void* _NSConcreteMallocBlock[32];
+
+template<typename> class BlockPtr;
+
+template<typename R, typename... Args>
+class BlockPtr<R (Args...)> {
+public:
+    using BlockType = R (^)(Args...);
+
+    template<typename F>
+    static BlockPtr fromCallable(F function)
+    {
+        struct Descriptor {
+            uintptr_t reserved;
+            uintptr_t size;
+            void (*copy)(void *dst, const void *src);
+            void (*dispose)(const void *);
+        };
+
+        struct Block {
+            void* isa;
+            int32_t flags;
+            int32_t reserved;
+            R (*invoke)(void *, Args...);
+            const struct Descriptor* descriptor;
+            F f;
+        };
+
+        static const Descriptor descriptor {
+            0,
+            sizeof(Block),
+
+            // We keep the copy function null - the block is already on the heap
+            // so it should never be copied.
+            nullptr,
+
+            [](const void* ptr) {
+                static_cast<Block*>(const_cast<void*>(ptr))->f.~F();
+            }
+        };
+
+        Block* block = static_cast<Block*>(malloc(sizeof(Block)));
+        block->isa = _NSConcreteMallocBlock;
+
+        enum {
+            BLOCK_NEEDS_FREE = (1 << 24),
+            BLOCK_HAS_COPY_DISPOSE = (1 << 25),
+        };
+        const unsigned retainCount = 1;
+
+        block->flags = BLOCK_HAS_COPY_DISPOSE | BLOCK_NEEDS_FREE | (retainCount << 1);
+        block->reserved = 0;
+        block->invoke = [](void *ptr, Args... args) -> R {
+            return static_cast<Block*>(ptr)->f(std::forward<Args>(args)...);
+        };
+        block->descriptor = &descriptor;
+
+        new (&block->f) F { std::move(function) };
+
+        BlockPtr blockPtr;
+        blockPtr.m_block = reinterpret_cast<BlockType>(block);
+
+        return blockPtr;
+    }
+
+    BlockPtr()
+        : m_block(nullptr)
+    {
+    }
+
+    BlockPtr(BlockType block)
+        : m_block(Block_copy(block))
+    {
+    }
+
+    BlockPtr(const BlockPtr& other)
+        : m_block(Block_copy(other.m_block))
+    {
+    }
+    
+    BlockPtr(BlockPtr&& other)
+        : m_block(std::exchange(other.m_block, nullptr))
+    {
+    }
+    
+    ~BlockPtr()
+    {
+        Block_release(m_block);
+    }
+
+    BlockPtr& operator=(const BlockPtr& other)
+    {
+        if (this != &other) {
+            Block_release(m_block);
+            m_block = Block_copy(other.m_block);
+        }
+        
+        return *this;
+    }
+
+    BlockPtr& operator=(BlockPtr&& other)
+    {
+        ASSERT(this != &other);
+
+        Block_release(m_block);
+        m_block = std::exchange(other.m_block, nullptr);
+
+        return *this;
+    }
+
+    BlockType get() const { return m_block; }
+
+    explicit operator bool() const { return m_block; }
+    bool operator!() const { return !m_block; }
+
+    R operator()(Args... arguments) const
+    {
+        ASSERT(m_block);
+        
+        return m_block(std::forward<Args>(arguments)...);
+    }
+
+private:
+    BlockType m_block;
+};
+
+template<typename R, typename... Args>
+inline BlockPtr<R (Args...)> makeBlockPtr(R (^block)(Args...))
+{
+    return BlockPtr<R (Args...)>(block);
+}
+
+}
+
+using WTF::BlockPtr;
+using WTF::makeBlockPtr;
+