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Fix wxTlsValue<> memory leaks.

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Win32 API doesn't provide pthreads-like destructors, so we need to
emulate them to free per-thread allocated memory.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@63653 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
This commit is contained in:
Václav Slavík
2010-03-08 12:21:58 +00:00
parent a765eef35f
commit 49e714e127
4 changed files with 150 additions and 30 deletions
Download Patch File Download Diff File Expand all files Collapse all files

67
include/wx/msw/tls.h
View File

@@ -12,6 +12,8 @@
#define _WX_MSW_TLS_H_
#include "wx/msw/wrapwin.h"
#include "wx/thread.h"
#include "wx/vector.h"
// ----------------------------------------------------------------------------
// wxTlsKey is a helper class encapsulating a TLS slot
@@ -21,8 +23,9 @@ class wxTlsKey
{
public:
// ctor allocates a new key
wxTlsKey()
wxTlsKey(wxTlsDestructorFunction destructor)
{
m_destructor = destructor;
m_slot = ::TlsAlloc();
}
@@ -38,19 +41,75 @@ public:
// change the key value, return true if ok
bool Set(void *value)
{
return ::TlsSetValue(m_slot, value) != 0;
void *old = Get();
if ( ::TlsSetValue(m_slot, value) == 0 )
return false;
if ( old )
m_destructor(old);
// update m_allValues list of all values - remove old, add new
wxCriticalSectionLocker lock(m_csAllValues);
if ( old )
{
for ( wxVector<void*>::iterator i = m_allValues.begin();
i != m_allValues.end();
++i )
{
if ( *i == old )
{
if ( value )
*i = value;
else
m_allValues.erase(i);
return true;
}
}
wxFAIL_MSG( "previous wxTlsKey value not recorded in m_allValues" );
}
if ( value )
m_allValues.push_back(value);
return true;
}
// free the key
~wxTlsKey()
{
if ( IsOk() )
::TlsFree(m_slot);
if ( !IsOk() )
return;
// Win32 API doesn't have the equivalent of pthread's destructor, so we
// have to keep track of all allocated values and destroy them manually;
// ideally we'd do that at thread exit time, but since we could only
// do that with wxThread and not otherwise created threads, we do it
// here.
//
// TODO: We should still call destructors for wxTlsKey used in the
// thread from wxThread's thread shutdown code, *in addition*
// to doing it in ~wxTlsKey.
//
// NB: No need to lock m_csAllValues, by the time this code is called,
// no other thread can be using this key.
for ( wxVector<void*>::iterator i = m_allValues.begin();
i != m_allValues.end();
++i )
{
m_destructor(*i);
}
::TlsFree(m_slot);
}
private:
wxTlsDestructorFunction m_destructor;
DWORD m_slot;
wxVector<void*> m_allValues;
wxCriticalSection m_csAllValues;
wxDECLARE_NO_COPY_CLASS(wxTlsKey);
};

63
include/wx/os2/tls.h
View File

@@ -12,6 +12,8 @@
#define _WX_OS2_TLS_H_
#include "wx/os2/private.h"
#include "wx/thread.h"
#include "wx/vector.h"
// ----------------------------------------------------------------------------
// wxTlsKey is a helper class encapsulating a TLS slot
@@ -21,8 +23,9 @@ class wxTlsKey
{
public:
// ctor allocates a new key
wxTlsKey()
wxTlsKey(wxTlsDestructorFunction destructor)
{
m_destructor = destructor;
APIRET rc = ::DosAllocThreadLocalMemory(1, &m_slot);
if (rc != NO_ERROR)
m_slot = NULL;
@@ -40,20 +43,74 @@ public:
// change the key value, return true if ok
bool Set(void *value)
{
void *old = Get();
m_slot = (ULONG*)value;
if ( old )
m_destructor(old);
// update m_allValues list of all values - remove old, add new
wxCriticalSectionLocker lock(m_csAllValues);
if ( old )
{
for ( wxVector<void*>::iterator i = m_allValues.begin();
i != m_allValues.end();
++i )
{
if ( *i == old )
{
if ( value )
*i = value;
else
m_allValues.erase(i);
return true;
}
}
wxFAIL_MSG( "previous wxTlsKey value not recorded in m_allValues" );
}
if ( value )
m_allValues.push_back(value);
return true;
}
// free the key
~wxTlsKey()
{
if ( IsOk() )
::DosFreeThreadLocalMemory(m_slot);
if ( !IsOk() )
return;
// Win32 and OS/2 API doesn't have the equivalent of pthread's
// destructor, so we have to keep track of all allocated values and
// destroy them manually; ideally we'd do that at thread exit time, but
// since we could only do that with wxThread and not otherwise created
// threads, we do it here.
//
// TODO: We should still call destructors for wxTlsKey used in the
// thread from wxThread's thread shutdown code, *in addition*
// to doing it in ~wxTlsKey.
//
// NB: No need to lock m_csAllValues, by the time this code is called,
// no other thread can be using this key.
for ( wxVector<void*>::iterator i = m_allValues.begin();
i != m_allValues.end();
++i )
{
m_destructor(*i);
}
::DosFreeThreadLocalMemory(m_slot);
}
private:
wxTlsDestructorFunction m_destructor;
ULONG* m_slot;
wxVector<void*> m_allValues;
wxCriticalSection m_csAllValues;
wxDECLARE_NO_COPY_CLASS(wxTlsKey);
};

39
include/wx/tls.h
View File

@@ -44,7 +44,13 @@
#define wxTLS_PTR(var) (&(var))
#define wxTLS_VALUE(var) (var)
#else // !wxHAS_COMPILER_TLS
#ifdef __WXMSW__
extern "C"
{
typedef void (*wxTlsDestructorFunction)(void*);
}
#if defined(__WXMSW__)
#include "wx/msw/tls.h"
#elif defined(__OS2__)
#include "wx/os2/tls.h"
@@ -60,6 +66,14 @@
// 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
{
@@ -67,32 +81,17 @@
typedef T ValueType;
// ctor doesn't do anything, the object is created on first access
//
// FIXME: the thread-specific values are currently not freed under
// Windows, resulting in memory leaks, this must be implemented
// there somehow (probably by keeping a list of all TLS objects
// and cleaning them up in wxThread cleanup)
wxTlsValue()
#if !defined(__OS2__) && defined(__UNIX__)
: m_key(free)
#endif
{
}
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) and simply leak the
// memory under Windows (see the FIXME above)
// just to be safe we also reset the key anyhow)
~wxTlsValue()
{
void * const value = m_key.Get();
if ( value)
{
free(value);
m_key.Set(NULL);
}
if ( m_key.Get() )
m_key.Set(NULL); // this deletes the value
}
// access the object creating it on demand

11
include/wx/unix/tls.h
View File

@@ -21,10 +21,10 @@ class wxTlsKey
{
public:
// ctor allocates a new key and possibly registering a destructor function
// for it (notice that using destructor function is Pthreads-specific and
// not supported in Win32 implementation)
wxTlsKey(void (*destructor)(void *) = NULL)
// for it
wxTlsKey(wxTlsDestructorFunction destructor)
{
m_destructor = destructor;
if ( pthread_key_create(&m_key, destructor) != 0 )
m_key = 0;
}
@@ -41,6 +41,10 @@ public:
// change the key value, return true if ok
bool Set(void *value)
{
void *old = Get();
if ( old )
m_destructor(old);
return pthread_setspecific(m_key, value) == 0;
}
@@ -52,6 +56,7 @@ public:
}
private:
wxTlsDestructorFunction m_destructor;
pthread_key_t m_key;
wxDECLARE_NO_COPY_CLASS(wxTlsKey);