102 lines
3.8 KiB
C
102 lines
3.8 KiB
C
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/****************************************************************************
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* libs/libnx/nxtk/nxtk_synch.c
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*
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* Copyright (C) 2019 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <nuttx/nx/nx.h>
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#include <nuttx/nx/nxtk.h>
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#include <nuttx/nx/nxmu.h>
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: nxtk_synch
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*
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* Description:
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* This interface can be used to syncrhonize the window client with the
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* NX server. It really just implements an 'echo': A synch message is
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* sent from the window client to the server which then responds
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* immediately by sending the NXEVENT_SYNCHED back to the windows client.
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*
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* Due to the highly asynchronous nature of client-server communications,
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* nxtk_synch() is sometimes necessary to assure that the client and server
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* are fully synchronized in time.
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*
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* Usage by the window client might be something like this:
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*
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* extern bool g_synched;
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* extern sem_t g_synch_sem;
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*
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* g_synched = false;
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* ret = nxtk_synch(hwnd, handle);
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* if (ret < 0)
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* {
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* -- Handle the error --
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* }
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*
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* while (!g_synched)
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* {
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* ret = sem_wait(&g_sync_sem);
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* if (ret < 0)
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* {
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* -- Handle the error --
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* }
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* }
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*
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* When the windwo listener thread receives the NXEVENT_SYNCHED event, it
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* would set g_synched to true and post g_synch_sem, waking up the above
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* loop.
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*
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* Input Parameters:
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* hfwnd - The window to be synched
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* arg - An argument that will accompany the block messages (This is arg2
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* in the event callback).
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*
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* Returned Value:
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* OK on success; ERROR on failure with errno set appropriately
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*
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****************************************************************************/
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int nxtk_synch(NXTKWINDOW hfwnd, FAR void *arg)
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{
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return nx_synch((NXWINDOW)hfwnd, arg);
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}
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