1 files changed, 125 insertions, 0 deletions
diff --git a/lib/asio/detail/call_stack.hpp b/lib/asio/detail/call_stack.hpp
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+++ b/lib/asio/detail/call_stack.hpp
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+//
+// detail/call_stack.hpp
+// ~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_CALL_STACK_HPP
+#define ASIO_DETAIL_CALL_STACK_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/noncopyable.hpp"
+#include "asio/detail/tss_ptr.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+// Helper class to determine whether or not the current thread is inside an
+// invocation of io_context::run() for a specified io_context object.
+template <typename Key, typename Value = unsigned char>
+class call_stack
+{
+public:
+  // Context class automatically pushes the key/value pair on to the stack.
+  class context
+    : private noncopyable
+  {
+  public:
+    // Push the key on to the stack.
+    explicit context(Key* k)
+      : key_(k),
+        next_(call_stack<Key, Value>::top_)
+    {
+      value_ = reinterpret_cast<unsigned char*>(this);
+      call_stack<Key, Value>::top_ = this;
+    }
+
+    // Push the key/value pair on to the stack.
+    context(Key* k, Value& v)
+      : key_(k),
+        value_(&v),
+        next_(call_stack<Key, Value>::top_)
+    {
+      call_stack<Key, Value>::top_ = this;
+    }
+
+    // Pop the key/value pair from the stack.
+    ~context()
+    {
+      call_stack<Key, Value>::top_ = next_;
+    }
+
+    // Find the next context with the same key.
+    Value* next_by_key() const
+    {
+      context* elem = next_;
+      while (elem)
+      {
+        if (elem->key_ == key_)
+          return elem->value_;
+        elem = elem->next_;
+      }
+      return 0;
+    }
+
+  private:
+    friend class call_stack<Key, Value>;
+
+    // The key associated with the context.
+    Key* key_;
+
+    // The value associated with the context.
+    Value* value_;
+
+    // The next element in the stack.
+    context* next_;
+  };
+
+  friend class context;
+
+  // Determine whether the specified owner is on the stack. Returns address of
+  // key if present, 0 otherwise.
+  static Value* contains(Key* k)
+  {
+    context* elem = top_;
+    while (elem)
+    {
+      if (elem->key_ == k)
+        return elem->value_;
+      elem = elem->next_;
+    }
+    return 0;
+  }
+
+  // Obtain the value at the top of the stack.
+  static Value* top()
+  {
+    context* elem = top_;
+    return elem ? elem->value_ : 0;
+  }
+
+private:
+  // The top of the stack of calls for the current thread.
+  static tss_ptr<context> top_;
+};
+
+template <typename Key, typename Value>
+tss_ptr<typename call_stack<Key, Value>::context>
+call_stack<Key, Value>::top_;
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_CALL_STACK_HPP