1 files changed, 92 insertions, 0 deletions
diff --git a/include/grpc/support/atm.h b/include/grpc/support/atm.h
new file mode 100644
index 0000000000..d9fd383209
--- /dev/null
+++ b/include/grpc/support/atm.h
@@ -0,0 +1,92 @@
+/*
+ *
+ * Copyright 2014, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef __GRPC_SUPPORT_ATM_H__
+#define __GRPC_SUPPORT_ATM_H__
+
+/* This interface provides atomic operations and barriers.
+   It is internal to gpr support code and should not be used outside it.
+
+   If an operation with acquire semantics precedes another memory access by the
+   same thread, the operation will precede that other access as seen by other
+   threads.
+
+   If an operation with release semantics follows another memory access by the
+   same thread, the operation will follow that other access as seen by other
+   threads.
+
+   Routines with "acq" or "full" in the name have acquire semantics.  Routines
+   with "rel" or "full" in the name have release semantics.  Routines with
+   "no_barrier" in the name have neither acquire not release semantics.
+
+   The routines may be implemented as macros.
+
+   // Atomic operations acton an intergral_type gpr_atm that is guaranteed to
+   // be the same size as a pointer.
+   typedef gpr_intptr gpr_atm;
+
+   // A memory barrier, providing both acquire and release semantics, but not
+   // otherwise acting no memory.
+   void gpr_atm_full_barrier(void);
+
+   // Atomically return *p, with acquire semantics.
+   gpr_atm gpr_atm_acq_load(gpr_atm *p);
+
+   // Atomically set *p = value, with release semantics.
+   void gpr_atm_rel_store(gpr_atm *p, gpr_atm value);
+
+   // Atomically add delta to *p, and return the old value of *p, with
+   // the barriers specified.
+   gpr_atm gpr_atm_no_barrier_fetch_add(gpr_atm *p, gpr_atm delta);
+   gpr_atm gpr_atm_full_fetch_add(gpr_atm *p, gpr_atm delta);
+
+   // Atomically, if *p==o, set *p=n and return non-zero otherwise return 0,
+   // with the barriers specified if the operation succeeds.
+   int gpr_atm_no_barrier_cas(gpr_atm *p, gpr_atm o, gpr_atm n);
+   int gpr_atm_acq_cas(gpr_atm *p, gpr_atm o, gpr_atm n);
+   int gpr_atm_rel_cas(gpr_atm *p, gpr_atm o, gpr_atm n);
+*/
+
+#include <grpc/support/port_platform.h>
+
+#if defined(GPR_GCC_ATOMIC)
+#include <grpc/support/atm_gcc_atomic.h>
+#elif defined(GPR_GCC_SYNC)
+#include <grpc/support/atm_gcc_sync.h>
+#elif defined(GPR_WIN32)
+#include <grpc/support/atm_win32.h>
+#else
+#error could not determine platform for atm
+#endif
+
+#endif  /* __GRPC_SUPPORT_ATM_H__ */