Adding upstream version 1:10.11.6.upstream/1%10.11.6upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 242 insertions, 0 deletions

diff --git a/mysys/wqueue.c b/mysys/wqueue.c
new file mode 100644
index 00000000..84fac01f
--- /dev/null
+++ b/mysys/wqueue.c
@@ -0,0 +1,242 @@
+/*
+   Copyright (c) 2007, 2008, Sun Microsystems, Inc,
+   Copyright (c) 2011, 2012, Monty Program Ab
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; version 2 of the License.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335 USA */
+
+#include <my_global.h>
+#include <wqueue.h>
+
+#define STRUCT_PTR(TYPE, MEMBER, a)                                           \
+          (TYPE *) ((char *) (a) - offsetof(TYPE, MEMBER))
+/*
+  Link a thread into double-linked queue of waiting threads.
+
+  SYNOPSIS
+    wqueue_link_into_queue()
+      wqueue              pointer to the queue structure
+      thread              pointer to the thread to be added to the queue
+
+  RETURN VALUE
+    none
+
+  NOTES.
+    Queue is represented by a circular list of the thread structures
+    The list is double-linked of the type (**prev,*next), accessed by
+    a pointer to the last element.
+*/
+
+void wqueue_link_into_queue(WQUEUE *wqueue, struct st_my_thread_var *thread)
+{
+  struct st_my_thread_var *last;
+  if (!(last= wqueue->last_thread))
+  {
+    /* Queue is empty */
+    thread->next= thread;
+    thread->prev= &thread->next;
+  }
+  else
+  {
+    thread->prev= last->next->prev;
+    last->next->prev= &thread->next;
+    thread->next= last->next;
+    last->next= thread;
+  }
+  wqueue->last_thread= thread;
+}
+
+
+/*
+  Add a thread to single-linked queue of waiting threads
+
+  SYNOPSIS
+    wqueue_add_to_queue()
+      wqueue              pointer to the queue structure
+      thread              pointer to the thread to be added to the queue
+
+  RETURN VALUE
+    none
+
+  NOTES.
+    Queue is represented by a circular list of the thread structures
+    The list is single-linked of the type (*next), accessed by a pointer
+    to the last element.
+*/
+
+void wqueue_add_to_queue(WQUEUE *wqueue, struct st_my_thread_var *thread)
+{
+  struct st_my_thread_var *last;
+  if (!(last= wqueue->last_thread))
+    thread->next= thread;
+  else
+  {
+    thread->next= last->next;
+    last->next= thread;
+  }
+#ifndef DBUG_OFF
+  thread->prev= NULL; /* force segfault if used */
+#endif
+  wqueue->last_thread= thread;
+}
+
+/*
+  Unlink a thread from double-linked queue of waiting threads
+
+  SYNOPSIS
+    wqueue_unlink_from_queue()
+      wqueue              pointer to the queue structure
+      thread              pointer to the thread to be removed from the queue
+
+  RETURN VALUE
+    none
+
+  NOTES.
+    See NOTES for link_into_queue
+*/
+
+void wqueue_unlink_from_queue(WQUEUE *wqueue, struct st_my_thread_var *thread)
+{
+  if (thread->next == thread)
+    /* The queue contains only one member */
+    wqueue->last_thread= NULL;
+  else
+  {
+    thread->next->prev= thread->prev;
+    *thread->prev= thread->next;
+    if (wqueue->last_thread == thread)
+      wqueue->last_thread= STRUCT_PTR(struct st_my_thread_var, next,
+                                      thread->prev);
+  }
+  thread->next= NULL;
+}
+
+
+/*
+  Remove all threads from queue signaling them to proceed
+
+  SYNOPSIS
+    wqueue_realease_queue()
+      wqueue              pointer to the queue structure
+      thread              pointer to the thread to be added to the queue
+
+  RETURN VALUE
+    none
+
+  NOTES.
+    See notes for add_to_queue
+    When removed from the queue each thread is signaled via condition
+    variable thread->suspend.
+*/
+
+void wqueue_release_queue(WQUEUE *wqueue)
+{
+  struct st_my_thread_var *last= wqueue->last_thread;
+  struct st_my_thread_var *next= last->next;
+  struct st_my_thread_var *thread;
+  do
+  {
+    thread= next;
+    mysql_cond_signal(&thread->suspend);
+    next= thread->next;
+    thread->next= NULL;
+  }
+  while (thread != last);
+  wqueue->last_thread= NULL;
+}
+
+
+/**
+  @brief Removes all threads waiting for read or first one waiting for write.
+
+  @param wqueue          pointer to the queue structure
+  @param thread          pointer to the thread to be added to the queue
+
+  @note This function is applicable only to single linked lists.
+*/
+
+void wqueue_release_one_locktype_from_queue(WQUEUE *wqueue)
+{
+  struct st_my_thread_var *last= wqueue->last_thread;
+  struct st_my_thread_var *next= last->next;
+  struct st_my_thread_var *thread;
+  struct st_my_thread_var *new_list= NULL;
+  uint first_type= next->lock_type;
+  if (first_type == MY_PTHREAD_LOCK_WRITE)
+  {
+    /* release first waiting for write lock */
+    mysql_cond_signal(&next->suspend);
+    if (next == last)
+      wqueue->last_thread= NULL;
+    else
+      last->next= next->next;
+    next->next= NULL;
+    return;
+  }
+  do
+  {
+    thread= next;
+    next= thread->next;
+    if (thread->lock_type == MY_PTHREAD_LOCK_WRITE)
+    {
+      /* skip waiting for write lock */
+      if (new_list)
+      {
+        thread->next= new_list->next;
+        new_list= new_list->next= thread;
+      }
+      else
+        new_list= thread->next= thread;
+    }
+    else
+    {
+      /* release waiting for read lock */
+      mysql_cond_signal(&thread->suspend);
+      thread->next= NULL;
+    }
+  } while (thread != last);
+  wqueue->last_thread= new_list;
+}
+
+
+/*
+  Add thread and wait
+
+  SYNOPSIS
+    wqueue_add_and_wait()
+    wqueue               queue to add to
+    thread               thread which is waiting
+    lock                 mutex need for the operation
+*/
+
+void wqueue_add_and_wait(WQUEUE *wqueue,
+                         struct st_my_thread_var *thread,
+                         mysql_mutex_t *lock)
+{
+  DBUG_ENTER("wqueue_add_and_wait");
+  DBUG_PRINT("enter",
+             ("thread: %p cond: %p mutex: %p",
+              thread, &thread->suspend, lock));
+  wqueue_add_to_queue(wqueue, thread);
+  do
+  {
+    DBUG_PRINT("info", ("wait... cond:  %p  mutex:  %p",
+                        &thread->suspend, lock));
+    mysql_cond_wait(&thread->suspend, lock);
+    DBUG_PRINT("info", ("wait done cond: %p mutex: %p next: %p",
+                        &thread->suspend, lock,
+                        thread->next));
+  }
+  while (thread->next);
+  DBUG_VOID_RETURN;
+}