333 lines
12 KiB
C++
Executable File
333 lines
12 KiB
C++
Executable File
/**
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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 <map>
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// std headers
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// external library headers
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#include <boost/dcoroutine/coroutine.hpp>
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#include <boost/dcoroutine/future.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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#include "lleventfilter.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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// By viewer convention, we post an event on the "mainloop" LLEventPump
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// each iteration of the main event-handling loop. So waiting for a single
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// event on "mainloop" gives us a one-frame suspend.
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suspendUntilEventOn("mainloop");
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}
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void llcoro::suspendUntilTimeout(float seconds)
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{
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LLEventTimeout timeout;
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timeout.eventAfter(seconds, LLSD());
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llcoro::suspendUntilEventOn(timeout);
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}
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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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// declare the future
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boost::dcoroutines::future<LLSD> future(LLCoros::get_self());
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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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std::string listenerName(listenerNameForCoro());
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LLTempBoundListener connection(
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replyPump.getPump().listen(listenerName,
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voidlistener(boost::dcoroutines::make_callback(future))));
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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") << "postAndSuspend(): 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") << "postAndSuspend(): coroutine " << listenerName
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<< " about to wait on LLEventPump " << replyPump.getPump().getName()
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<< LL_ENDL;
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// trying to dereference ("resolve") the future makes us wait for it
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LLSD value;
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{
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// instantiate Suspending to manage the "current" coroutine
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llcoro::Suspending suspended;
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value = *future;
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} // destroy Suspending as soon as we're back
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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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namespace
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{
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/**
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* This helper is specifically for the two-pump version of suspendUntilEventOn().
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* We use a single future object, but we want to listen on two pumps with it.
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* Since we must still adapt from (the callable constructed by)
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* boost::dcoroutines::make_callback() (void return) to provide an event
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* listener (bool return), we've adapted VoidListener for the purpose. The
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* basic idea is that we construct a distinct instance of WaitForEventOnHelper
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* -- binding different instance data -- for each of the pumps. Then, when a
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* pump delivers an LLSD value to either WaitForEventOnHelper, it can combine
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* that LLSD with its discriminator to feed the future object.
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*/
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template <typename LISTENER>
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class WaitForEventOnHelper
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{
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public:
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WaitForEventOnHelper(const LISTENER& listener, int discriminator):
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mListener(listener),
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mDiscrim(discriminator)
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{}
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// this signature is required for an LLEventPump listener
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bool operator()(const LLSD& event)
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{
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// our future object is defined to accept LLEventWithID
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mListener(LLEventWithID(event, mDiscrim));
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// don't swallow the event, let other listeners see it
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return false;
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}
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private:
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LISTENER mListener;
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const int mDiscrim;
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};
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/// WaitForEventOnHelper type-inference helper
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template <typename LISTENER>
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WaitForEventOnHelper<LISTENER> wfeoh(const LISTENER& listener, int discriminator)
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{
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return WaitForEventOnHelper<LISTENER>(listener, discriminator);
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}
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} // anonymous
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namespace llcoro
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{
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LLEventWithID postAndSuspend2(const LLSD& event,
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const LLEventPumpOrPumpName& requestPump,
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const LLEventPumpOrPumpName& replyPump0,
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const LLEventPumpOrPumpName& replyPump1,
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const LLSD& replyPump0NamePath,
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const LLSD& replyPump1NamePath)
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{
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// declare the future
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boost::dcoroutines::future<LLEventWithID> future(LLCoros::get_self());
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// either callback will assign a value to this future; listen on
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// each specified LLEventPump with a callback
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std::string name(listenerNameForCoro());
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LLTempBoundListener connection0(
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replyPump0.getPump().listen(name + "a",
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wfeoh(boost::dcoroutines::make_callback(future), 0)));
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LLTempBoundListener connection1(
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replyPump1.getPump().listen(name + "b",
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wfeoh(boost::dcoroutines::make_callback(future), 1)));
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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 either replyPumpNamePath is non-empty, store the corresponding
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// replyPump name in the request event.
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LLSD modevent(event);
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storeToLLSDPath(modevent, replyPump0NamePath,
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replyPump0.getPump().getName());
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storeToLLSDPath(modevent, replyPump1NamePath,
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replyPump1.getPump().getName());
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LL_DEBUGS("lleventcoro") << "postAndSuspend2(): coroutine " << name
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<< " posting to " << requestPump.getPump().getName()
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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") << "postAndSuspend2(): coroutine " << name
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<< " about to wait on LLEventPumps " << replyPump0.getPump().getName()
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<< ", " << replyPump1.getPump().getName() << LL_ENDL;
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// trying to dereference ("resolve") the future makes us wait for it
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LLEventWithID value;
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{
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// instantiate Suspending to manage "current" coroutine
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llcoro::Suspending suspended;
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value = *future;
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} // destroy Suspending as soon as we're back
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LL_DEBUGS("lleventcoro") << "postAndSuspend(): coroutine " << name
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<< " resuming with (" << value.first << ", " << value.second << ")"
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<< LL_ENDL;
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// returning should disconnect both connections
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return value;
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}
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LLSD errorException(const LLEventWithID& result, const std::string& desc)
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{
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// If the result arrived on the error pump (pump 1), instead of
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// returning it, deliver it via exception.
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if (result.second)
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{
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throw LLErrorEvent(desc, result.first);
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}
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// That way, our caller knows a simple return must be from the reply
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// pump (pump 0).
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return result.first;
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}
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LLSD errorLog(const LLEventWithID& result, const std::string& desc)
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{
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// If the result arrived on the error pump (pump 1), log it as a fatal
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// error.
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if (result.second)
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{
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LL_ERRS("errorLog") << desc << ":" << std::endl;
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LLSDSerialize::toPrettyXML(result.first, LL_CONT);
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LL_CONT << LL_ENDL;
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}
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// A simple return must therefore be from the reply pump (pump 0).
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return result.first;
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}
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} // namespace llcoro
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