| /* |
| * |
| * Copyright 2015, 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 |
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| * (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_INTERNAL_CORE_IOMGR_ALARM_H |
| #define GRPC_INTERNAL_CORE_IOMGR_ALARM_H |
| |
| #include "src/core/iomgr/iomgr.h" |
| #include <grpc/support/port_platform.h> |
| #include <grpc/support/time.h> |
| |
| typedef struct grpc_alarm { |
| gpr_timespec deadline; |
| gpr_uint32 heap_index; /* INVALID_HEAP_INDEX if not in heap */ |
| struct grpc_alarm *next; |
| struct grpc_alarm *prev; |
| int triggered; |
| grpc_iomgr_cb_func cb; |
| void *cb_arg; |
| } grpc_alarm; |
| |
| /* Initialize *alarm. When expired or canceled, alarm_cb will be called with |
| *alarm_cb_arg and status to indicate if it expired (SUCCESS) or was |
| canceled (CANCELLED). alarm_cb is guaranteed to be called exactly once, |
| and application code should check the status to determine how it was |
| invoked. The application callback is also responsible for maintaining |
| information about when to free up any user-level state. */ |
| void grpc_alarm_init(grpc_alarm *alarm, gpr_timespec deadline, |
| grpc_iomgr_cb_func alarm_cb, void *alarm_cb_arg, |
| gpr_timespec now); |
| |
| /* Note that there is no alarm destroy function. This is because the |
| alarm is a one-time occurrence with a guarantee that the callback will |
| be called exactly once, either at expiration or cancellation. Thus, all |
| the internal alarm event management state is destroyed just before |
| that callback is invoked. If the user has additional state associated with |
| the alarm, the user is responsible for determining when it is safe to |
| destroy that state. */ |
| |
| /* Cancel an *alarm. |
| There are three cases: |
| 1. We normally cancel the alarm |
| 2. The alarm has already run |
| 3. We can't cancel the alarm because it is "in flight". |
| |
| In all of these cases, the cancellation is still considered successful. |
| They are essentially distinguished in that the alarm_cb will be run |
| exactly once from either the cancellation (with status CANCELLED) |
| or from the activation (with status SUCCESS) |
| |
| Note carefully that the callback function MAY occur in the same callstack |
| as grpc_alarm_cancel. It's expected that most alarms will be cancelled (their |
| primary use is to implement deadlines), and so this code is optimized such |
| that cancellation costs as little as possible. Making callbacks run inline |
| matches this aim. |
| |
| Requires: cancel() must happen after add() on a given alarm */ |
| void grpc_alarm_cancel(grpc_alarm *alarm); |
| |
| #endif /* GRPC_INTERNAL_CORE_IOMGR_ALARM_H */ |