1 files changed, 112 insertions, 0 deletions
diff --git a/libgo/runtime/go-send-nb-small.c b/libgo/runtime/go-send-nb-small.c
new file mode 100644
index 000000000..f23ae0164
--- /dev/null
+++ b/libgo/runtime/go-send-nb-small.c
@@ -0,0 +1,112 @@
+/* go-send-nb-small.c -- nonblocking send of something small on a channel.
+
+   Copyright 2009 The Go Authors. All rights reserved.
+   Use of this source code is governed by a BSD-style
+   license that can be found in the LICENSE file.  */
+
+#include <stdint.h>
+
+#include "go-assert.h"
+#include "go-panic.h"
+#include "channel.h"
+
+/* Prepare to send something on a nonblocking channel.  */
+
+int
+__go_send_nonblocking_acquire (struct __go_channel *channel)
+{
+  int i;
+  _Bool has_space;
+
+  i = pthread_mutex_lock (&channel->lock);
+  __go_assert (i == 0);
+
+  while (channel->selected_for_send)
+    {
+      i = pthread_cond_wait (&channel->cond, &channel->lock);
+      __go_assert (i == 0);
+    }
+
+  if (channel->is_closed)
+    {
+      ++channel->closed_op_count;
+      if (channel->closed_op_count >= MAX_CLOSED_OPERATIONS)
+	{
+	  i = pthread_mutex_unlock (&channel->lock);
+	  __go_assert (i == 0);
+	  __go_panic_msg ("too many operations on closed channel");
+	}
+      i = pthread_mutex_unlock (&channel->lock);
+      __go_assert (i == 0);
+      return SEND_NONBLOCKING_ACQUIRE_CLOSED;
+    }
+
+  if (channel->num_entries > 0)
+      has_space = ((channel->next_store + 1) % channel->num_entries
+		   != channel->next_fetch);
+  else
+    {
+      /* This is a synchronous channel.  If somebody is current
+	 sending, then we can't send.  Otherwise, see if somebody is
+	 waiting to receive, or see if we can synch with a select.  */
+      if (channel->waiting_to_send)
+	{
+	  /* Some other goroutine is currently sending on this
+	     channel, which means that we can't.  */
+	  has_space = 0;
+	}
+      else if (channel->waiting_to_receive)
+	{
+	  /* Some other goroutine is waiting to receive a value, so we
+	     can send directly to them.  */
+	  has_space = 1;
+	}
+      else if (__go_synch_with_select (channel, 1))
+	{
+	  /* We found a select waiting to receive data, so we can send
+	     to that.  */
+	  __go_broadcast_to_select (channel);
+	  has_space = 1;
+	}
+      else
+	{
+	  /* Otherwise, we can't send, because nobody is waiting to
+	     receive.  */
+	  has_space = 0;
+	}
+
+      if (has_space)
+	{
+	  channel->waiting_to_send = 1;
+	  __go_assert (channel->next_store == 0);
+	}
+    }
+
+  if (!has_space)
+    {
+      i = pthread_mutex_unlock (&channel->lock);
+      __go_assert (i == 0);
+
+      return SEND_NONBLOCKING_ACQUIRE_NOSPACE;
+    }
+
+  return SEND_NONBLOCKING_ACQUIRE_SPACE;
+}
+
+/* Send something 64 bits or smaller on a channel.  */
+
+_Bool
+__go_send_nonblocking_small (struct __go_channel *channel, uint64_t val)
+{
+  __go_assert (channel->element_size <= sizeof (uint64_t));
+
+  int data = __go_send_nonblocking_acquire (channel);
+  if (data != SEND_NONBLOCKING_ACQUIRE_SPACE)
+    return data == SEND_NONBLOCKING_ACQUIRE_CLOSED;
+
+  channel->data[channel->next_store] = val;
+
+  __go_send_release (channel);
+
+  return 1;
+}