dolphin/Externals/wxWidgets3/include/wx/tls.h

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///////////////////////////////////////////////////////////////////////////////
// Name: wx/tls.h
// Purpose: Implementation of thread local storage
// Author: Vadim Zeitlin
// Created: 2008-08-08
// RCS-ID: $Id: tls.h 65747 2010-10-03 17:16:15Z VZ $
// Copyright: (c) 2008 Vadim Zeitlin <vadim@wxwidgets.org>
// Licence: wxWindows licence
///////////////////////////////////////////////////////////////////////////////
#ifndef _WX_TLS_H_
#define _WX_TLS_H_
#include "wx/defs.h"
// ----------------------------------------------------------------------------
// check for compiler support of thread-specific variables
// ----------------------------------------------------------------------------
// when not using threads at all, there is no need for thread-specific
// values to be really thread-specific
#if !wxUSE_THREADS
#define wxHAS_COMPILER_TLS
#define wxTHREAD_SPECIFIC_DECL
// __thread keyword is not supported correctly by MinGW, at least in some
// configurations, see http://sourceforge.net/support/tracker.php?aid=2837047
// and when in doubt we prefer to not use it at all.
#elif defined(HAVE___THREAD_KEYWORD) && !defined(__MINGW32__)
#define wxHAS_COMPILER_TLS
#define wxTHREAD_SPECIFIC_DECL __thread
// MSVC has its own version which might be supported by some other Windows
// compilers, to be tested
#elif wxCHECK_VISUALC_VERSION(7)
#define wxHAS_COMPILER_TLS
#define wxTHREAD_SPECIFIC_DECL __declspec(thread)
#endif
// ----------------------------------------------------------------------------
// define wxTLS_TYPE()
// ----------------------------------------------------------------------------
#ifdef wxHAS_COMPILER_TLS
#define wxTLS_TYPE(T) wxTHREAD_SPECIFIC_DECL T
#define wxTLS_PTR(var) (&(var))
#define wxTLS_VALUE(var) (var)
#else // !wxHAS_COMPILER_TLS
extern "C"
{
typedef void (*wxTlsDestructorFunction)(void*);
}
#if defined(__WXMSW__)
#include "wx/msw/tls.h"
#elif defined(__OS2__)
#include "wx/os2/tls.h"
#elif defined(__UNIX__)
#include "wx/unix/tls.h"
#else
// TODO: we could emulate TLS for such platforms...
#error Neither compiler nor OS support thread-specific variables.
#endif
#include <stdlib.h> // for calloc()
// wxTlsValue<T> represents a thread-specific value of type T but, unlike
// with native compiler thread-specific variables, it behaves like a
// (never NULL) pointer to T and so needs to be dereferenced before use
//
// Note: T must be a POD!
//
// Note: On Unix, thread-specific T value is freed when the thread exits.
// On Windows, thread-specific values are freed later, when given
// wxTlsValue<T> is destroyed. The only exception to this is the
// value for the main thread, which is always freed when
// wxTlsValue<T> is destroyed.
template <typename T>
class wxTlsValue
{
public:
typedef T ValueType;
// ctor doesn't do anything, the object is created on first access
wxTlsValue() : m_key(free) {}
// dtor is only called in the main thread context and so is not enough
// to free memory allocated by us for the other threads, we use
// destructor function when using Pthreads for this (which is not
// called for the main thread as it doesn't call pthread_exit() but
// just to be safe we also reset the key anyhow)
~wxTlsValue()
{
if ( m_key.Get() )
m_key.Set(NULL); // this deletes the value
}
// access the object creating it on demand
ValueType *Get()
{
void *value = m_key.Get();
if ( !value )
{
// ValueType must be POD to be used in wxHAS_COMPILER_TLS case
// anyhow (at least gcc doesn't accept non-POD values being
// declared with __thread) so initialize it as a POD too
value = calloc(1, sizeof(ValueType));
if ( !m_key.Set(value) )
{
free(value);
// this will probably result in a crash in the caller but
// it's arguably better to crash immediately instead of
// slowly dying from out-of-memory errors which would
// happen as the next access to this object would allocate
// another ValueType instance and so on forever
value = NULL;
}
}
return static_cast<ValueType *>(value);
}
// pointer-like accessors
ValueType *operator->() { return Get(); }
ValueType& operator*() { return *Get(); }
private:
wxTlsKey m_key;
DECLARE_NO_COPY_TEMPLATE_CLASS(wxTlsValue, T)
};
#define wxTLS_TYPE(T) wxTlsValue<T>
#define wxTLS_PTR(var) (var)
#define wxTLS_VALUE(var) (*(var))
#endif // wxHAS_COMPILER_TLS/!wxHAS_COMPILER_TLS
#endif // _WX_TLS_H_