1 files changed, 167 insertions, 0 deletions
diff --git a/mysys/wqueue.c b/mysys/wqueue.c
new file mode 100644
index 00000000000..28e044ff606
--- /dev/null
+++ b/mysys/wqueue.c
@@ -0,0 +1,167 @@
+
+#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;
+  }
+  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;
+    pthread_cond_signal(&thread->suspend);
+    next= thread->next;
+    thread->next= NULL;
+  }
+  while (thread != last);
+  wqueue->last_thread= NULL;
+}
+
+
+/*
+  Add thread and wait
+
+  SYNOPSYS
+    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, pthread_mutex_t *lock)
+{
+  DBUG_ENTER("wqueue_add_and_wait");
+  DBUG_PRINT("enter", ("thread ox%lxcond 0x%lx, mutex 0x%lx",
+                       (ulong) thread, (ulong) &thread->suspend, (ulong) lock));
+  wqueue_add_to_queue(wqueue, thread);
+  do
+  {
+    DBUG_PRINT("info", ("wait... cond 0x%lx, mutex 0x%lx",
+                        (ulong) &thread->suspend, (ulong) lock));
+    pthread_cond_wait(&thread->suspend, lock);
+    DBUG_PRINT("info", ("wait done cond 0x%lx, mutex 0x%lx, next 0x%lx",
+                        (ulong) &thread->suspend, (ulong) lock,
+                        (ulong) thread->next));
+  }
+  while (thread->next);
+  DBUG_VOID_RETURN;
+}