271 lines
10 KiB
C++
271 lines
10 KiB
C++
/**
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* @file lleventcoro.cpp
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* @author Nat Goodspeed
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* @date 2009-04-29
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* @brief Implementation for lleventcoro.
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*
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* $LicenseInfo:firstyear=2009&license=viewerlgpl$
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* Second Life Viewer Source Code
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* Copyright (C) 2010, Linden Research, Inc.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation;
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* version 2.1 of the License only.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*
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* Linden Research, Inc., 945 Battery Street, San Francisco, CA 94111 USA
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* $/LicenseInfo$
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*/
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// Precompiled header
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#include "linden_common.h"
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// associated header
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#include "lleventcoro.h"
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// STL headers
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#include <chrono>
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// std headers
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// external library headers
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#include <boost/fiber/operations.hpp>
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// other Linden headers
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#include "llsdserialize.h"
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#include "llerror.h"
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#include "llcoros.h"
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namespace
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{
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/**
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* suspendUntilEventOn() permits a coroutine to temporarily listen on an
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* LLEventPump any number of times. We don't really want to have to ask
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* the caller to label each such call with a distinct string; the whole
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* point of suspendUntilEventOn() is to present a nice sequential interface to
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* the underlying LLEventPump-with-named-listeners machinery. So we'll use
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* LLEventPump::inventName() to generate a distinct name for each
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* temporary listener. On the other hand, because a given coroutine might
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* call suspendUntilEventOn() any number of times, we don't really want to
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* consume an arbitrary number of generated inventName()s: that namespace,
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* though large, is nonetheless finite. So we memoize an invented name for
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* each distinct coroutine instance.
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*/
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std::string listenerNameForCoro()
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{
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// If this coroutine was launched by LLCoros::launch(), find that name.
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std::string name(LLCoros::instance().getName());
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if (! name.empty())
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{
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return name;
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}
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// this is the first time we've been called for this coroutine instance
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name = LLEventPump::inventName("coro");
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LL_INFOS("LLEventCoro") << "listenerNameForCoro(): inventing coro name '"
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<< name << "'" << LL_ENDL;
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return name;
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}
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/**
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* Implement behavior described for postAndSuspend()'s @a replyPumpNamePath
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* parameter:
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*
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* * If <tt>path.isUndefined()</tt>, do nothing.
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* * If <tt>path.isString()</tt>, @a dest is an LLSD map: store @a value
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* into <tt>dest[path.asString()]</tt>.
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* * If <tt>path.isInteger()</tt>, @a dest is an LLSD array: store @a
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* value into <tt>dest[path.asInteger()]</tt>.
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* * If <tt>path.isArray()</tt>, iteratively apply the rules above to step
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* down through the structure of @a dest. The last array entry in @a
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* path specifies the entry in the lowest-level structure in @a dest
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* into which to store @a value.
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*
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* @note
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* In the degenerate case in which @a path is an empty array, @a dest will
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* @em become @a value rather than @em containing it.
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*/
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void storeToLLSDPath(LLSD& dest, const LLSD& rawPath, const LLSD& value)
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{
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if (rawPath.isUndefined())
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{
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// no-op case
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return;
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}
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// Arrange to treat rawPath uniformly as an array. If it's not already an
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// array, store it as the only entry in one.
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LLSD path;
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if (rawPath.isArray())
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{
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path = rawPath;
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}
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else
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{
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path.append(rawPath);
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}
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// Need to indicate a current destination -- but that current destination
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// needs to change as we step through the path array. Where normally we'd
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// use an LLSD& to capture a subscripted LLSD lvalue, this time we must
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// instead use a pointer -- since it must be reassigned.
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LLSD* pdest = &dest;
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// Now loop through that array
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for (LLSD::Integer i = 0; i < path.size(); ++i)
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{
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if (path[i].isString())
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{
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// *pdest is an LLSD map
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pdest = &((*pdest)[path[i].asString()]);
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}
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else if (path[i].isInteger())
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{
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// *pdest is an LLSD array
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pdest = &((*pdest)[path[i].asInteger()]);
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}
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else
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{
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// What do we do with Real or Array or Map or ...?
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// As it's a coder error -- not a user error -- rub the coder's
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// face in it so it gets fixed.
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LL_ERRS("lleventcoro") << "storeToLLSDPath(" << dest << ", " << rawPath << ", " << value
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<< "): path[" << i << "] bad type " << path[i].type() << LL_ENDL;
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}
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}
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// Here *pdest is where we should store value.
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*pdest = value;
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}
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} // anonymous
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void llcoro::suspend()
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{
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boost::this_fiber::yield();
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}
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void llcoro::suspendUntilTimeout(float seconds)
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{
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// The fact that we accept non-integer seconds means we should probably
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// use granularity finer than one second. However, given the overhead of
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// the rest of our processing, it seems silly to use granularity finer
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// than a millisecond.
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boost::this_fiber::sleep_for(std::chrono::milliseconds(long(seconds * 1000)));
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}
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namespace
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{
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LLBoundListener postAndSuspendSetup(const std::string& callerName,
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const std::string& listenerName,
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LLCoros::Promise<LLSD>& promise,
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const LLSD& event,
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const LLEventPumpOrPumpName& requestPump,
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const LLEventPumpOrPumpName& replyPump,
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const LLSD& replyPumpNamePath)
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{
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// Get the consuming attribute for THIS coroutine, the one that's about to
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// suspend. Don't call get_consuming() in the lambda body: that would
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// return the consuming attribute for some other coroutine, most likely
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// the main routine.
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bool consuming(LLCoros::get_consuming());
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// make a callback that will assign a value to the future, and listen on
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// the specified LLEventPump with that callback
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LLBoundListener connection(
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replyPump.getPump().listen(listenerName,
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[&promise, consuming](const LLSD& result)
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{
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promise.set_value(result);
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return consuming;
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}));
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// skip the "post" part if requestPump is default-constructed
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if (requestPump)
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{
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// If replyPumpNamePath is non-empty, store the replyPump name in the
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// request event.
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LLSD modevent(event);
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storeToLLSDPath(modevent, replyPumpNamePath, replyPump.getPump().getName());
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LL_DEBUGS("lleventcoro") << callerName << ": coroutine " << listenerName
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<< " posting to " << requestPump.getPump().getName()
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<< LL_ENDL;
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// *NOTE:Mani - Removed because modevent could contain user's hashed passwd.
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// << ": " << modevent << LL_ENDL;
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requestPump.getPump().post(modevent);
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}
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LL_DEBUGS("lleventcoro") << callerName << ": coroutine " << listenerName
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<< " about to wait on LLEventPump " << replyPump.getPump().getName()
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<< LL_ENDL;
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return connection;
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}
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} // anonymous
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LLSD llcoro::postAndSuspend(const LLSD& event, const LLEventPumpOrPumpName& requestPump,
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const LLEventPumpOrPumpName& replyPump, const LLSD& replyPumpNamePath)
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{
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LLCoros::Promise<LLSD> promise;
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std::string listenerName(listenerNameForCoro());
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// Store connection into an LLTempBoundListener so we implicitly
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// disconnect on return from this function.
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LLTempBoundListener connection =
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postAndSuspendSetup("postAndSuspend()", listenerName, promise,
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event, requestPump, replyPump, replyPumpNamePath);
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// declare the future
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LLCoros::Future<LLSD> future = LLCoros::getFuture(promise);
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// calling get() on the future makes us wait for it
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LLSD value(future.get());
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LL_DEBUGS("lleventcoro") << "postAndSuspend(): coroutine " << listenerName
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<< " resuming with " << value << LL_ENDL;
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// returning should disconnect the connection
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return value;
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}
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LLSD llcoro::postAndSuspendWithTimeout(const LLSD& event,
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const LLEventPumpOrPumpName& requestPump,
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const LLEventPumpOrPumpName& replyPump,
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const LLSD& replyPumpNamePath,
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F32 timeout, const LLSD& timeoutResult)
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{
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LLCoros::Promise<LLSD> promise;
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std::string listenerName(listenerNameForCoro());
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// Store connection into an LLTempBoundListener so we implicitly
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// disconnect on return from this function.
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LLTempBoundListener connection =
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postAndSuspendSetup("postAndSuspendWithTimeout()", listenerName, promise,
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event, requestPump, replyPump, replyPumpNamePath);
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// declare the future
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LLCoros::Future<LLSD> future = LLCoros::getFuture(promise);
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// wait for specified timeout
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boost::fibers::future_status status =
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future.wait_for(std::chrono::milliseconds(long(timeout * 1000)));
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// if the future is NOT yet ready, return timeoutResult instead
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if (status == boost::fibers::future_status::timeout)
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{
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LL_DEBUGS("lleventcoro") << "postAndSuspendWithTimeout(): coroutine " << listenerName
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<< " timed out after " << timeout << " seconds,"
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<< " resuming with " << timeoutResult << LL_ENDL;
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return timeoutResult;
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}
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else
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{
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llassert_always(status == boost::fibers::future_status::ready);
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// future is now ready, no more waiting
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LLSD value(future.get());
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LL_DEBUGS("lleventcoro") << "postAndSuspendWithTimeout(): coroutine " << listenerName
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<< " resuming with " << value << LL_ENDL;
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// returning should disconnect the connection
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return value;
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}
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}
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