Mojo: Move common/basic functions declarations from mojo/public/c/system/core.h to .../functions.h.

mojo/public/c/system/functions.h

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// This file contains basic functions common to different Mojo system APIs.
+//
+// Note: This header should be compilable as C.
+
+#ifndef MOJO_PUBLIC_C_SYSTEM_FUNCTIONS_H_
+#define MOJO_PUBLIC_C_SYSTEM_FUNCTIONS_H_
+
+// Note: This header should be compilable as C.
+
+#include "mojo/public/c/system/system_export.h"
+#include "mojo/public/c/system/types.h"
+
+// Note: Pointer parameters that are labelled "optional" may be null (at least
+// under some circumstances). Non-const pointer parameters are also labeled
+// "in", "out", or "in/out", to indicate how they are used. (Note that how/if
+// such a parameter is used may depend on other parameters or the requested
+// operation's success/failure. E.g., a separate |flags| parameter may control
+// whether a given "in/out" parameter is used for input, output, or both.)
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+// Platform-dependent monotonically increasing tick count representing "right
+// now." The resolution of this clock is ~1-15ms.  Resolution varies depending
+// on hardware/operating system configuration.
+MOJO_SYSTEM_EXPORT MojoTimeTicks MojoGetTimeTicksNow();
+
+// Closes the given |handle|.
+//
+// Returns:
+//   |MOJO_RESULT_OK| on success.
+//   |MOJO_RESULT_INVALID_ARGUMENT| if |handle| is not a valid handle.
+//
+// Concurrent operations on |handle| may succeed (or fail as usual) if they
+// happen before the close, be cancelled with result |MOJO_RESULT_CANCELLED| if
+// they properly overlap (this is likely the case with |MojoWait()|, etc.), or
+// fail with |MOJO_RESULT_INVALID_ARGUMENT| if they happen after.
+MOJO_SYSTEM_EXPORT MojoResult MojoClose(MojoHandle handle);
+
+// Waits on the given handle until the state indicated by |flags| is satisfied
+// or until |deadline| has passed.
+//
+// Returns:
+//   |MOJO_RESULT_OK| if some flag in |flags| was satisfied (or is already
+//        satisfied).
+//   |MOJO_RESULT_INVALID_ARGUMENT| if |handle| is not a valid handle (e.g., if
+//       it has already been closed).
+//   |MOJO_RESULT_DEADLINE_EXCEEDED| if the deadline has passed without any of
+//       the flags being satisfied.
+//   |MOJO_RESULT_FAILED_PRECONDITION| if it is or becomes impossible that any
+//       flag in |flags| will ever be satisfied.
+//
+// If there are multiple waiters (on different threads, obviously) waiting on
+// the same handle and flag and that flag becomes set, all waiters will be
+// awoken.
+MOJO_SYSTEM_EXPORT MojoResult MojoWait(MojoHandle handle,
+                                       MojoWaitFlags flags,
+                                       MojoDeadline deadline);
+
+// Waits on |handles[0]|, ..., |handles[num_handles-1]| for at least one of them
+// to satisfy the state indicated by |flags[0]|, ..., |flags[num_handles-1]|,
+// respectively, or until |deadline| has passed.
+//
+// Returns:
+//   The index |i| (from 0 to |num_handles-1|) if |handle[i]| satisfies
+//       |flags[i]|.
+//   |MOJO_RESULT_INVALID_ARGUMENT| if some |handle[i]| is not a valid handle
+//       (e.g., if it has already been closed).
+//   |MOJO_RESULT_DEADLINE_EXCEEDED| if the deadline has passed without any of
+//       handles satisfying any of its flags.
+//   |MOJO_RESULT_FAILED_PRECONDITION| if it is or becomes impossible that SOME
+//       |handle[i]| will ever satisfy any of its flags |flags[i]|.
+MOJO_SYSTEM_EXPORT MojoResult MojoWaitMany(const MojoHandle* handles,
+                                           const MojoWaitFlags* flags,
+                                           uint32_t num_handles,
+                                           MojoDeadline deadline);
+
+#ifdef __cplusplus
+}  // extern "C"
+#endif
+
+#endif  // MOJO_PUBLIC_C_SYSTEM_FUNCTIONS_H_