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|
/*===========================================================================
FILE:
Event.cpp
DESCRIPTION:
Implementation of cEvent class
PUBLIC CLASSES AND METHODS:
WaitOnMultipleEvents
cEvent
Functionality to mimic Windows events using UNIX pipes (enhanced
somewhat to allow one to specify a DWORD value to pass through
when signalling the event)
WARNING:
This class is not designed to be thread safe
Copyright (c) 2011, Code Aurora Forum. 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 Code Aurora Forum 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.
===========================================================================*/
//---------------------------------------------------------------------------
// Include Files
//---------------------------------------------------------------------------
#include "StdAfx.h"
#include "Event.h"
/*===========================================================================
METHOD:
WaitOnMultipleEvents (Free Method)
DESCRIPTION:
Wait for any of the events to be set and return the value
Note: If multiple events are set, only the event specified by
eventIndex will be read from. Run this function again
to get the next event.
PARAMETERS:
events [ I ] - Vector of events which may be signaled
timeoutMS [ I ] - Relative timeout length (in milliseconds)
val [ O ] - Associated value upon success
eventIndex [ O ] - Index of event which was signaled
RETURN VALUE:
Return code
positive for number of events set
-ETIME on timeout
negative errno value on failure
===========================================================================*/
int WaitOnMultipleEvents(
std::vector <cEvent *> events,
DWORD timeoutMS,
DWORD & val,
DWORD & eventIndex )
{
// Check internal pipes' status
for (int index = 0; index < events.size(); index++)
{
int error = events[index]->mError;
if (error != 0)
{
TRACE( "cEvent %d has error %d\n", index, error );
return -error;
}
}
// Initialize the FD set
fd_set fds;
FD_ZERO( &fds );
// Add each item to the FD set, keeping track of the largest,
// which is used for select()
int largestFD = 0;
for (int index = 0; index < events.size(); index++)
{
int pipe = events[index]->mPipes[READING];
FD_SET( pipe, &fds );
largestFD = std::max( pipe, largestFD );
}
struct timeval timeOut;
// Add avoiding an overflow on (long)usec
timeOut.tv_sec = timeoutMS / 1000l;
timeOut.tv_usec = ( timeoutMS % 1000l ) * 1000l;
// Wait for activity on the pipes for the specified amount of time
int rc = select( largestFD + 1, &fds, 0, 0, &timeOut );
if (rc == -1)
{
TRACE( "WaitOnMultipleEvents error %d\n", errno );
return -errno;
}
else if (rc == 0)
{
// No activity on the pipes
return -ETIME;
}
int numSignaled = rc;
// Only read from first pipe which was signaled
int signaled = -1;
for (int index = 0; index < events.size(); index++)
{
int pipe = events[index]->mPipes[READING];
if (FD_ISSET( pipe, &fds ) != 0)
{
signaled = index;
break;
}
}
if (signaled == -1)
{
// Odd, no one was signaled
return -ENODATA;
}
DWORD tempVal = 0;
rc = events[signaled]->Read( tempVal );
if (rc == 0)
{
// Success
val = tempVal;
eventIndex = signaled;
return numSignaled;
}
else
{
// failure
return rc;
}
}
/*=========================================================================*/
// cEvent Methods
/*=========================================================================*/
/*===========================================================================
METHOD:
cEvent (Public Method)
DESCRIPTION:
Constructor
RETURN VALUE:
None
===========================================================================*/
cEvent::cEvent()
: mError( 0 )
{
int rc = pipe( mPipes );
if (rc != 0)
{
mError = errno;
TRACE( "cEvent - Error %d creating pipe, %s\n",
mError,
strerror( mError ) );
}
}
/*===========================================================================
METHOD:
~cEvent (Public Method)
DESCRIPTION:
Destructor
RETURN VALUE:
None
===========================================================================*/
cEvent::~cEvent()
{
// Check internal pipe status
if (mError == 0)
{
Close();
mError = EBADF;
}
}
/*===========================================================================
METHOD:
Close (Internal Method)
DESCRIPTION:
Close pipe
RETURN VALUE:
Return code
0 on success
errno value on failure
===========================================================================*/
int cEvent::Close()
{
int retCode = 0;
int rc = close( mPipes[READING] );
mPipes[READING] = -1;
if (rc != 0)
{
retCode = errno;
TRACE( "cEvent - Error %d deleting pipe[READING], %s\n",
retCode,
strerror( retCode ) );
}
rc = close( mPipes[WRITING] );
mPipes[WRITING] = -1;
if (rc != 0)
{
retCode = errno;
TRACE( "cEvent - Error %d deleting pipe[WRITING], %s\n",
retCode,
strerror( retCode ) );
}
return retCode;
}
/*===========================================================================
METHOD:
Set (Public Method)
DESCRIPTION:
Set/signal the event with the specified value
PARAMETERS:
val [ I ] - Value to pass through with signal
RETURN VALUE:
Return code
0 on success
errno value on failure
===========================================================================*/
int cEvent::Set( DWORD val )
{
// Check internal pipe status
if (mError != 0)
{
return mError;
}
PBYTE pWrite = (PBYTE)&val;
int writeSize = sizeof( DWORD );
while (writeSize > 0)
{
int bytesWritten = write( mPipes[WRITING], pWrite, writeSize );
if (bytesWritten == -1)
{
// Store error from write
int writeErr = errno;
// First error?
if (mError == 0)
{
// Yes, save the error
mError = writeErr;
}
// We cannot recover from this error
Close();
return writeErr;
}
pWrite += bytesWritten;
writeSize -= bytesWritten;
}
// Success
return 0;
}
/*===========================================================================
METHOD:
Wait (Free Method)
DESCRIPTION:
Wait for the event to be signalled and return the read in value
PARAMETERS:
timeoutMS [ I ] - Relative timeout length (in milliseconds)
val [ O ] - Associated value upon success
RETURN VALUE:
Return code
0 on success
ETIME on timeout
errno value on failure
===========================================================================*/
int cEvent::Wait(
DWORD timeoutMS,
DWORD & val )
{
// Check internal pipe status
if (mError != 0)
{
return mError;
}
fd_set fds;
FD_ZERO( &fds );
FD_SET( mPipes[READING], &fds );
struct timeval timeOut;
// Add avoiding an overflow on (long)usec
timeOut.tv_sec = timeoutMS / 1000l;
timeOut.tv_usec = ( timeoutMS % 1000l ) * 1000l;
// Wait for activity on the pipe for the specified amount of time
int rc = select( mPipes[READING] + 1, &fds, 0, 0, &timeOut );
if (rc == -1)
{
// Store error from select
int selectErr = errno;
// First error?
if (mError == 0)
{
// Yes, save the error
mError = selectErr;
}
// We cannot recover from this error
Close();
return selectErr;
}
else if (rc == 0)
{
// No activity on the pipe
return ETIME;
}
return Read( val );
}
/*===========================================================================
METHOD:
Clear (Free Method)
DESCRIPTION:
Read and discard all values currently in the pipe
===========================================================================*/
void cEvent::Clear()
{
DWORD unusedVal;
int rc = 0;
while (rc == 0)
{
rc = Wait( (DWORD)0, unusedVal );
}
}
/*===========================================================================
METHOD:
Read (Internal Method)
DESCRIPTION:
Read a DWORD from the pipe
RETURN VALUE:
Return code
0 on success
errno value on failure
===========================================================================*/
int cEvent::Read( DWORD & val )
{
DWORD tempVal;
PBYTE pRead = (PBYTE)&tempVal;
int readSize = sizeof( DWORD );
while (readSize > 0)
{
int bytesRead = read( mPipes[READING], pRead, readSize );
if (bytesRead <= 0)
{
// Store error from read
int readErr = errno;
if (readErr == 0)
{
// Hard error! This should NEVER happen for a pipe
ASSERT( 0 );
readErr = EBADF;
}
// First error?
if (mError == 0)
{
// Yes, store the error
mError = readErr;
}
// We cannot recover from this error
Close();
return readErr;
}
pRead += bytesRead;
readSize -= bytesRead;
}
val = tempVal;
return 0;
}
|