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[glib: 1/3] gthread-win32: Remove WinXP compat code

commit cce29579389e892eb263d8507a71b3b3ca7433bb
Author: Christoph Reiter <reiter christoph gmail com>
Date:   Tue May 29 17:10:05 2018 +0200

    gthread-win32: Remove WinXP compat code

 glib/gthread-win32.c | 564 ++-------------------------------------------------
 1 file changed, 16 insertions(+), 548 deletions(-)
---
diff --git a/glib/gthread-win32.c b/glib/gthread-win32.c
index a81f00a5c..1ad5ece80 100644
--- a/glib/gthread-win32.c
+++ b/glib/gthread-win32.c
@@ -73,81 +73,36 @@ g_thread_abort (gint         status,
  * of these new types is that they can be statically initialised to
  * zero.  That means that they are completely ABI compatible with our
  * GMutex and GCond APIs.
- *
- * Unfortunately, Windows XP lacks these facilities and GLib still
- * needs to support Windows XP.  Our approach here is as follows:
- *
- *   - avoid depending on structure declarations at compile-time by
- *     declaring our own GMutex and GCond strutures to be
- *     ABI-compatible with SRWLock and CONDITION_VARIABLE and using
- *     those instead
- *
- *   - avoid a hard dependency on the symbols used to manipulate these
- *     structures by doing a dynamic lookup of those symbols at
- *     runtime
- *
- *   - if the symbols are not available, emulate them using other
- *     primatives
- *
- * Using this approach also allows us to easily build a GLib that lacks
- * support for Windows XP or to remove this code entirely when XP is no
- * longer supported (end of line is currently April 8, 2014).
  */
-typedef struct
-{
-  void     (__stdcall * CallThisOnThreadExit)        (void);              /* fake */
-
-  void     (__stdcall * InitializeSRWLock)           (gpointer lock);
-  void     (__stdcall * DeleteSRWLock)               (gpointer lock);     /* fake */
-  void     (__stdcall * AcquireSRWLockExclusive)     (gpointer lock);
-  BOOLEAN  (__stdcall * TryAcquireSRWLockExclusive)  (gpointer lock);
-  void     (__stdcall * ReleaseSRWLockExclusive)     (gpointer lock);
-  void     (__stdcall * AcquireSRWLockShared)        (gpointer lock);
-  BOOLEAN  (__stdcall * TryAcquireSRWLockShared)     (gpointer lock);
-  void     (__stdcall * ReleaseSRWLockShared)        (gpointer lock);
-
-  void     (__stdcall * InitializeConditionVariable) (gpointer cond);
-  void     (__stdcall * DeleteConditionVariable)     (gpointer cond);     /* fake */
-  BOOL     (__stdcall * SleepConditionVariableSRW)   (gpointer cond,
-                                                      gpointer lock,
-                                                      DWORD    timeout,
-                                                      ULONG    flags);
-  void     (__stdcall * WakeAllConditionVariable)    (gpointer cond);
-  void     (__stdcall * WakeConditionVariable)       (gpointer cond);
-} GThreadImplVtable;
-
-static GThreadImplVtable g_thread_impl_vtable;
 
 /* {{{1 GMutex */
 void
 g_mutex_init (GMutex *mutex)
 {
-  g_thread_impl_vtable.InitializeSRWLock (mutex);
+  InitializeSRWLock ((gpointer) mutex);
 }
 
 void
 g_mutex_clear (GMutex *mutex)
 {
-  if (g_thread_impl_vtable.DeleteSRWLock != NULL)
-    g_thread_impl_vtable.DeleteSRWLock (mutex);
 }
 
 void
 g_mutex_lock (GMutex *mutex)
 {
-  g_thread_impl_vtable.AcquireSRWLockExclusive (mutex);
+  AcquireSRWLockExclusive ((gpointer) mutex);
 }
 
 gboolean
 g_mutex_trylock (GMutex *mutex)
 {
-  return g_thread_impl_vtable.TryAcquireSRWLockExclusive (mutex);
+  return TryAcquireSRWLockExclusive ((gpointer) mutex);
 }
 
 void
 g_mutex_unlock (GMutex *mutex)
 {
-  g_thread_impl_vtable.ReleaseSRWLockExclusive (mutex);
+  ReleaseSRWLockExclusive ((gpointer) mutex);
 }
 
 /* {{{1 GRecMutex */
@@ -221,83 +176,79 @@ g_rec_mutex_trylock (GRecMutex *mutex)
 void
 g_rw_lock_init (GRWLock *lock)
 {
-  g_thread_impl_vtable.InitializeSRWLock (lock);
+  InitializeSRWLock ((gpointer) lock);
 }
 
 void
 g_rw_lock_clear (GRWLock *lock)
 {
-  if (g_thread_impl_vtable.DeleteSRWLock != NULL)
-    g_thread_impl_vtable.DeleteSRWLock (lock);
 }
 
 void
 g_rw_lock_writer_lock (GRWLock *lock)
 {
-  g_thread_impl_vtable.AcquireSRWLockExclusive (lock);
+  AcquireSRWLockExclusive ((gpointer) lock);
 }
 
 gboolean
 g_rw_lock_writer_trylock (GRWLock *lock)
 {
-  return g_thread_impl_vtable.TryAcquireSRWLockExclusive (lock);
+  return TryAcquireSRWLockExclusive ((gpointer) lock);
 }
 
 void
 g_rw_lock_writer_unlock (GRWLock *lock)
 {
-  g_thread_impl_vtable.ReleaseSRWLockExclusive (lock);
+  ReleaseSRWLockExclusive ((gpointer) lock);
 }
 
 void
 g_rw_lock_reader_lock (GRWLock *lock)
 {
-  g_thread_impl_vtable.AcquireSRWLockShared (lock);
+  AcquireSRWLockShared ((gpointer) lock);
 }
 
 gboolean
 g_rw_lock_reader_trylock (GRWLock *lock)
 {
-  return g_thread_impl_vtable.TryAcquireSRWLockShared (lock);
+  return TryAcquireSRWLockShared ((gpointer) lock);
 }
 
 void
 g_rw_lock_reader_unlock (GRWLock *lock)
 {
-  g_thread_impl_vtable.ReleaseSRWLockShared (lock);
+  ReleaseSRWLockShared ((gpointer) lock);
 }
 
 /* {{{1 GCond */
 void
 g_cond_init (GCond *cond)
 {
-  g_thread_impl_vtable.InitializeConditionVariable (cond);
+  InitializeConditionVariable ((gpointer) cond);
 }
 
 void
 g_cond_clear (GCond *cond)
 {
-  if (g_thread_impl_vtable.DeleteConditionVariable)
-    g_thread_impl_vtable.DeleteConditionVariable (cond);
 }
 
 void
 g_cond_signal (GCond *cond)
 {
-  g_thread_impl_vtable.WakeConditionVariable (cond);
+  WakeConditionVariable ((gpointer) cond);
 }
 
 void
 g_cond_broadcast (GCond *cond)
 {
-  g_thread_impl_vtable.WakeAllConditionVariable (cond);
+  WakeAllConditionVariable ((gpointer) cond);
 }
 
 void
 g_cond_wait (GCond  *cond,
              GMutex *entered_mutex)
 {
-  g_thread_impl_vtable.SleepConditionVariableSRW (cond, entered_mutex, INFINITE, 0);
+  SleepConditionVariableSRW ((gpointer) cond, (gpointer) entered_mutex, INFINITE, 0);
 }
 
 gboolean
@@ -326,7 +277,7 @@ g_cond_wait_until (GCond  *cond,
       if (span_millis >= INFINITE)
         span_millis = INFINITE - 1;
 
-      signalled = g_thread_impl_vtable.SleepConditionVariableSRW (cond, entered_mutex, span_millis, 0);
+      signalled = SleepConditionVariableSRW ((gpointer) cond, (gpointer) entered_mutex, span_millis, 0);
       if (signalled)
         break;
 
@@ -580,491 +531,11 @@ g_system_thread_set_name (const gchar *name)
   SetThreadName ((DWORD) -1, name);
 }
 
-/* {{{1 SRWLock and CONDITION_VARIABLE emulation (for Windows XP) */
-
-static CRITICAL_SECTION g_thread_xp_lock;
-static DWORD            g_thread_xp_waiter_tls;
-
-/* {{{2 GThreadWaiter utility class for CONDITION_VARIABLE emulation */
-typedef struct _GThreadXpWaiter GThreadXpWaiter;
-struct _GThreadXpWaiter
-{
-  HANDLE                     event;
-  volatile GThreadXpWaiter  *next;
-  volatile GThreadXpWaiter **my_owner;
-};
-
-static GThreadXpWaiter *
-g_thread_xp_waiter_get (void)
-{
-  GThreadXpWaiter *waiter;
-
-  waiter = TlsGetValue (g_thread_xp_waiter_tls);
-
-  if G_UNLIKELY (waiter == NULL)
-    {
-      waiter = malloc (sizeof (GThreadXpWaiter));
-      if (waiter == NULL)
-        g_thread_abort (GetLastError (), "malloc");
-      waiter->event = CreateEvent (0, FALSE, FALSE, NULL);
-      if (waiter->event == NULL)
-        g_thread_abort (GetLastError (), "CreateEvent");
-      waiter->my_owner = NULL;
-
-      TlsSetValue (g_thread_xp_waiter_tls, waiter);
-    }
-
-  return waiter;
-}
-
-static void __stdcall
-g_thread_xp_CallThisOnThreadExit (void)
-{
-  GThreadXpWaiter *waiter;
-
-  waiter = TlsGetValue (g_thread_xp_waiter_tls);
-
-  if (waiter != NULL)
-    {
-      TlsSetValue (g_thread_xp_waiter_tls, NULL);
-      CloseHandle (waiter->event);
-      free (waiter);
-    }
-}
-
-/* {{{2 SRWLock emulation */
-typedef struct
-{
-  CRITICAL_SECTION  writer_lock;
-  gboolean          ever_shared;    /* protected by writer_lock */
-  gboolean          writer_locked;  /* protected by writer_lock */
-
-  /* below is only ever touched if ever_shared becomes true */
-  CRITICAL_SECTION  atomicity;
-  GThreadXpWaiter  *queued_writer; /* protected by atomicity lock */
-  gint              num_readers;   /* protected by atomicity lock */
-} GThreadSRWLock;
-
-static void __stdcall
-g_thread_xp_InitializeSRWLock (gpointer mutex)
-{
-  *(GThreadSRWLock * volatile *) mutex = NULL;
-}
-
-static void __stdcall
-g_thread_xp_DeleteSRWLock (gpointer mutex)
-{
-  GThreadSRWLock *lock = *(GThreadSRWLock * volatile *) mutex;
-
-  if (lock)
-    {
-      if (lock->ever_shared)
-        DeleteCriticalSection (&lock->atomicity);
-
-      DeleteCriticalSection (&lock->writer_lock);
-      free (lock);
-    }
-}
-
-static GThreadSRWLock * __stdcall
-g_thread_xp_get_srwlock (GThreadSRWLock * volatile *lock)
-{
-  GThreadSRWLock *result;
-
-  /* It looks like we're missing some barriers here, but this code only
-   * ever runs on Windows XP, which in turn only ever runs on hardware
-   * with a relatively rigid memory model.  The 'volatile' will take
-   * care of the compiler.
-   */
-  result = *lock;
-
-  if G_UNLIKELY (result == NULL)
-    {
-      EnterCriticalSection (&g_thread_xp_lock);
-
-      /* Check again */
-      result = *lock;
-      if (result == NULL)
-        {
-          result = malloc (sizeof (GThreadSRWLock));
-
-          if (result == NULL)
-            g_thread_abort (errno, "malloc");
-
-          InitializeCriticalSection (&result->writer_lock);
-          result->writer_locked = FALSE;
-          result->ever_shared = FALSE;
-          *lock = result;
-        }
-
-      LeaveCriticalSection (&g_thread_xp_lock);
-    }
-
-  return result;
-}
-
-static void __stdcall
-g_thread_xp_AcquireSRWLockExclusive (gpointer mutex)
-{
-  GThreadSRWLock *lock = g_thread_xp_get_srwlock (mutex);
-
-  EnterCriticalSection (&lock->writer_lock);
-
-  /* CRITICAL_SECTION is reentrant, but SRWLock is not.
-   * Detect the deadlock that would occur on later Windows version.
-   */
-  g_assert (!lock->writer_locked);
-  lock->writer_locked = TRUE;
-
-  if (lock->ever_shared)
-    {
-      GThreadXpWaiter *waiter = NULL;
-
-      EnterCriticalSection (&lock->atomicity);
-      if (lock->num_readers > 0)
-        lock->queued_writer = waiter = g_thread_xp_waiter_get ();
-      LeaveCriticalSection (&lock->atomicity);
-
-      if (waiter != NULL)
-        WaitForSingleObject (waiter->event, INFINITE);
-
-      lock->queued_writer = NULL;
-    }
-}
-
-static BOOLEAN __stdcall
-g_thread_xp_TryAcquireSRWLockExclusive (gpointer mutex)
-{
-  GThreadSRWLock *lock = g_thread_xp_get_srwlock (mutex);
-
-  if (!TryEnterCriticalSection (&lock->writer_lock))
-    return FALSE;
-
-  /* CRITICAL_SECTION is reentrant, but SRWLock is not.
-   * Ensure that this properly returns FALSE (as SRWLock would).
-   */
-  if G_UNLIKELY (lock->writer_locked)
-    {
-      LeaveCriticalSection (&lock->writer_lock);
-      return FALSE;
-    }
-
-  lock->writer_locked = TRUE;
-
-  if (lock->ever_shared)
-    {
-      gboolean available;
-
-      EnterCriticalSection (&lock->atomicity);
-      available = lock->num_readers == 0;
-      LeaveCriticalSection (&lock->atomicity);
-
-      if (!available)
-        {
-          LeaveCriticalSection (&lock->writer_lock);
-          return FALSE;
-        }
-    }
-
-  return TRUE;
-}
-
-static void __stdcall
-g_thread_xp_ReleaseSRWLockExclusive (gpointer mutex)
-{
-  GThreadSRWLock *lock = *(GThreadSRWLock * volatile *) mutex;
-
-  lock->writer_locked = FALSE;
-
-  /* We need this until we fix some weird parts of GLib that try to
-   * unlock freshly-allocated mutexes.
-   */
-  if (lock != NULL)
-    LeaveCriticalSection (&lock->writer_lock);
-}
-
-static void
-g_thread_xp_srwlock_become_reader (GThreadSRWLock *lock)
-{
-  if G_UNLIKELY (!lock->ever_shared)
-    {
-      InitializeCriticalSection (&lock->atomicity);
-      lock->queued_writer = NULL;
-      lock->num_readers = 0;
-
-      lock->ever_shared = TRUE;
-    }
-
-  EnterCriticalSection (&lock->atomicity);
-  lock->num_readers++;
-  LeaveCriticalSection (&lock->atomicity);
-}
-
-static void __stdcall
-g_thread_xp_AcquireSRWLockShared (gpointer mutex)
-{
-  GThreadSRWLock *lock = g_thread_xp_get_srwlock (mutex);
-
-  EnterCriticalSection (&lock->writer_lock);
-
-  /* See g_thread_xp_AcquireSRWLockExclusive */
-  g_assert (!lock->writer_locked);
-
-  g_thread_xp_srwlock_become_reader (lock);
-
-  LeaveCriticalSection (&lock->writer_lock);
-}
-
-static BOOLEAN __stdcall
-g_thread_xp_TryAcquireSRWLockShared (gpointer mutex)
-{
-  GThreadSRWLock *lock = g_thread_xp_get_srwlock (mutex);
-
-  if (!TryEnterCriticalSection (&lock->writer_lock))
-    return FALSE;
-
-  /* See g_thread_xp_AcquireSRWLockExclusive */
-  if G_UNLIKELY (lock->writer_locked)
-    {
-      LeaveCriticalSection (&lock->writer_lock);
-      return FALSE;
-    }
-
-  g_thread_xp_srwlock_become_reader (lock);
-
-  LeaveCriticalSection (&lock->writer_lock);
-
-  return TRUE;
-}
-
-static void __stdcall
-g_thread_xp_ReleaseSRWLockShared (gpointer mutex)
-{
-  GThreadSRWLock *lock = g_thread_xp_get_srwlock (mutex);
-
-  EnterCriticalSection (&lock->atomicity);
-
-  lock->num_readers--;
-
-  if (lock->num_readers == 0 && lock->queued_writer)
-    SetEvent (lock->queued_writer->event);
-
-  LeaveCriticalSection (&lock->atomicity);
-}
-
-/* {{{2 CONDITION_VARIABLE emulation */
-typedef struct
-{
-  volatile GThreadXpWaiter  *first;
-  volatile GThreadXpWaiter **last_ptr;
-} GThreadXpCONDITION_VARIABLE;
-
-static void __stdcall
-g_thread_xp_InitializeConditionVariable (gpointer cond)
-{
-  *(GThreadXpCONDITION_VARIABLE * volatile *) cond = NULL;
-}
-
-static void __stdcall
-g_thread_xp_DeleteConditionVariable (gpointer cond)
-{
-  GThreadXpCONDITION_VARIABLE *cv = *(GThreadXpCONDITION_VARIABLE * volatile *) cond;
-
-  if (cv)
-    free (cv);
-}
-
-static GThreadXpCONDITION_VARIABLE * __stdcall
-g_thread_xp_get_condition_variable (GThreadXpCONDITION_VARIABLE * volatile *cond)
-{
-  GThreadXpCONDITION_VARIABLE *result;
-
-  /* It looks like we're missing some barriers here, but this code only
-   * ever runs on Windows XP, which in turn only ever runs on hardware
-   * with a relatively rigid memory model.  The 'volatile' will take
-   * care of the compiler.
-   */
-  result = *cond;
-
-  if G_UNLIKELY (result == NULL)
-    {
-      result = malloc (sizeof (GThreadXpCONDITION_VARIABLE));
-
-      if (result == NULL)
-        g_thread_abort (errno, "malloc");
-
-      result->first = NULL;
-      result->last_ptr = &result->first;
-
-      if (InterlockedCompareExchangePointer (cond, result, NULL) != NULL)
-        {
-          free (result);
-          result = *cond;
-        }
-    }
-
-  return result;
-}
-
-static BOOL __stdcall
-g_thread_xp_SleepConditionVariableSRW (gpointer cond,
-                                       gpointer mutex,
-                                       DWORD    timeout,
-                                       ULONG    flags)
-{
-  GThreadXpCONDITION_VARIABLE *cv = g_thread_xp_get_condition_variable (cond);
-  GThreadXpWaiter *waiter = g_thread_xp_waiter_get ();
-  DWORD status;
-
-  waiter->next = NULL;
-
-  EnterCriticalSection (&g_thread_xp_lock);
-  waiter->my_owner = cv->last_ptr;
-  *cv->last_ptr = waiter;
-  cv->last_ptr = &waiter->next;
-  LeaveCriticalSection (&g_thread_xp_lock);
-
-  g_mutex_unlock (mutex);
-  status = WaitForSingleObject (waiter->event, timeout);
-
-  if (status != WAIT_TIMEOUT && status != WAIT_OBJECT_0)
-    g_thread_abort (GetLastError (), "WaitForSingleObject");
-  g_mutex_lock (mutex);
-
-  if (status == WAIT_TIMEOUT)
-    {
-      EnterCriticalSection (&g_thread_xp_lock);
-      if (waiter->my_owner)
-        {
-          if (waiter->next)
-            waiter->next->my_owner = waiter->my_owner;
-          else
-            cv->last_ptr = waiter->my_owner;
-          *waiter->my_owner = waiter->next;
-          waiter->my_owner = NULL;
-        }
-      LeaveCriticalSection (&g_thread_xp_lock);
-    }
-
-  return status == WAIT_OBJECT_0;
-}
-
-static void __stdcall
-g_thread_xp_WakeConditionVariable (gpointer cond)
-{
-  GThreadXpCONDITION_VARIABLE *cv = g_thread_xp_get_condition_variable (cond);
-  volatile GThreadXpWaiter *waiter;
-
-  EnterCriticalSection (&g_thread_xp_lock);
-
-  waiter = cv->first;
-  if (waiter != NULL)
-    {
-      waiter->my_owner = NULL;
-      cv->first = waiter->next;
-      if (cv->first != NULL)
-        cv->first->my_owner = &cv->first;
-      else
-        cv->last_ptr = &cv->first;
-    }
-
-  if (waiter != NULL)
-    SetEvent (waiter->event);
-
-  LeaveCriticalSection (&g_thread_xp_lock);
-}
-
-static void __stdcall
-g_thread_xp_WakeAllConditionVariable (gpointer cond)
-{
-  GThreadXpCONDITION_VARIABLE *cv = g_thread_xp_get_condition_variable (cond);
-  volatile GThreadXpWaiter *waiter;
-
-  EnterCriticalSection (&g_thread_xp_lock);
-
-  waiter = cv->first;
-  cv->first = NULL;
-  cv->last_ptr = &cv->first;
-
-  while (waiter != NULL)
-    {
-      volatile GThreadXpWaiter *next;
-
-      next = waiter->next;
-      SetEvent (waiter->event);
-      waiter->my_owner = NULL;
-      waiter = next;
-    }
-
-  LeaveCriticalSection (&g_thread_xp_lock);
-}
-
-/* {{{2 XP Setup */
-static void
-g_thread_xp_init (void)
-{
-  static const GThreadImplVtable g_thread_xp_impl_vtable = {
-    g_thread_xp_CallThisOnThreadExit,
-    g_thread_xp_InitializeSRWLock,
-    g_thread_xp_DeleteSRWLock,
-    g_thread_xp_AcquireSRWLockExclusive,
-    g_thread_xp_TryAcquireSRWLockExclusive,
-    g_thread_xp_ReleaseSRWLockExclusive,
-    g_thread_xp_AcquireSRWLockShared,
-    g_thread_xp_TryAcquireSRWLockShared,
-    g_thread_xp_ReleaseSRWLockShared,
-    g_thread_xp_InitializeConditionVariable,
-    g_thread_xp_DeleteConditionVariable,
-    g_thread_xp_SleepConditionVariableSRW,
-    g_thread_xp_WakeAllConditionVariable,
-    g_thread_xp_WakeConditionVariable
-  };
-
-  InitializeCriticalSection (&g_thread_xp_lock);
-  g_thread_xp_waiter_tls = TlsAlloc ();
-
-  g_thread_impl_vtable = g_thread_xp_impl_vtable;
-}
-
 /* {{{1 Epilogue */
 
-static gboolean
-g_thread_lookup_native_funcs (void)
-{
-  GThreadImplVtable native_vtable = { 0, };
-  HMODULE kernel32;
-
-  kernel32 = GetModuleHandle ("KERNEL32.DLL");
-
-  if (kernel32 == NULL)
-    return FALSE;
-
-#define GET_FUNC(name) if ((native_vtable.name = (void *) GetProcAddress (kernel32, #name)) == NULL) return 
FALSE
-  GET_FUNC(InitializeSRWLock);
-  GET_FUNC(AcquireSRWLockExclusive);
-  GET_FUNC(TryAcquireSRWLockExclusive);
-  GET_FUNC(ReleaseSRWLockExclusive);
-  GET_FUNC(AcquireSRWLockShared);
-  GET_FUNC(TryAcquireSRWLockShared);
-  GET_FUNC(ReleaseSRWLockShared);
-
-  GET_FUNC(InitializeConditionVariable);
-  GET_FUNC(SleepConditionVariableSRW);
-  GET_FUNC(WakeAllConditionVariable);
-  GET_FUNC(WakeConditionVariable);
-#undef GET_FUNC
-
-  g_thread_impl_vtable = native_vtable;
-
-  return TRUE;
-}
-
 void
 g_thread_win32_init (void)
 {
-  if (!g_thread_lookup_native_funcs ())
-    g_thread_xp_init ();
-
   InitializeCriticalSection (&g_private_lock);
 
 #ifndef _MSC_VER
@@ -1109,9 +580,6 @@ g_thread_win32_thread_detach (void)
         }
     }
   while (dtors_called);
-
-  if (g_thread_impl_vtable.CallThisOnThreadExit)
-    g_thread_impl_vtable.CallThisOnThreadExit ();
 }
 
 void
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