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SingularityViewer/indra/llcommon/llevents.cpp
2012-02-23 18:50:28 +01:00

629 lines
24 KiB
C++

/**
* @file llevents.cpp
* @author Nat Goodspeed
* @date 2008-09-12
* @brief Implementation for llevents.
*
* $LicenseInfo:firstyear=2008&license=viewerlgpl$
* Second Life Viewer Source Code
* Copyright (C) 2010, Linden Research, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation;
* version 2.1 of the License only.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*
* Linden Research, Inc., 945 Battery Street, San Francisco, CA 94111 USA
* $/LicenseInfo$
*/
// Precompiled header
#include "linden_common.h"
#if LL_WINDOWS
#pragma warning (disable : 4675) // "resolved by ADL" -- just as I want!
#endif
// associated header
#include "llevents.h"
// STL headers
#include <set>
#include <sstream>
#include <algorithm>
// std headers
#include <typeinfo>
#include <cassert>
#include <cmath>
#include <cctype>
// external library headers
#include <boost/range/iterator_range.hpp>
#if LL_WINDOWS
#pragma warning (push)
#pragma warning (disable : 4701) // compiler thinks might use uninitialized var, but no
#endif
#include <boost/lexical_cast.hpp>
#if LL_WINDOWS
#pragma warning (pop)
#endif
// other Linden headers
#include "stringize.h"
#include "llerror.h"
#include "llsdutil.h"
#if LL_MSVC
#pragma warning (disable : 4702)
#endif
/*****************************************************************************
* queue_names: specify LLEventPump names that should be instantiated as
* LLEventQueue
*****************************************************************************/
/**
* At present, we recognize particular requested LLEventPump names as needing
* LLEventQueues. Later on we'll migrate this information to an external
* configuration file.
*/
const char* queue_names[] =
{
"placeholder - replace with first real name string"
};
/*****************************************************************************
* If there's a "mainloop" pump, listen on that to flush all LLEventQueues
*****************************************************************************/
struct RegisterFlush : public LLEventTrackable
{
RegisterFlush():
pumps(LLEventPumps::instance())
{
pumps.obtain("mainloop").listen("flushLLEventQueues", boost::bind(&RegisterFlush::flush, this, _1));
}
bool flush(const LLSD&)
{
pumps.flush();
return false;
}
~RegisterFlush()
{
// LLEventTrackable handles stopListening for us.
}
LLEventPumps& pumps;
};
static RegisterFlush registerFlush;
/*****************************************************************************
* LLEventPumps
*****************************************************************************/
LLEventPumps::LLEventPumps():
// Until we migrate this information to an external config file,
// initialize mQueueNames from the static queue_names array.
mQueueNames(boost::begin(queue_names), boost::end(queue_names))
{
}
LLEventPump& LLEventPumps::obtain(const std::string& name)
{
PumpMap::iterator found = mPumpMap.find(name);
if (found != mPumpMap.end())
{
// Here we already have an LLEventPump instance with the requested
// name.
return *found->second;
}
// Here we must instantiate an LLEventPump subclass.
LLEventPump* newInstance;
// Should this name be an LLEventQueue?
PumpNames::const_iterator nfound = mQueueNames.find(name);
if (nfound != mQueueNames.end())
newInstance = new LLEventQueue(name);
else
newInstance = new LLEventStream(name);
// LLEventPump's constructor implicitly registers each new instance in
// mPumpMap. But remember that we instantiated it (in mOurPumps) so we'll
// delete it later.
mOurPumps.insert(newInstance);
return *newInstance;
}
void LLEventPumps::flush()
{
// Flush every known LLEventPump instance. Leave it up to each instance to
// decide what to do with the flush() call.
for (PumpMap::iterator pmi = mPumpMap.begin(), pmend = mPumpMap.end(); pmi != pmend; ++pmi)
{
pmi->second->flush();
}
}
void LLEventPumps::reset()
{
// Reset every known LLEventPump instance. Leave it up to each instance to
// decide what to do with the reset() call.
for (PumpMap::iterator pmi = mPumpMap.begin(), pmend = mPumpMap.end(); pmi != pmend; ++pmi)
{
pmi->second->reset();
}
}
std::string LLEventPumps::registerNew(const LLEventPump& pump, const std::string& name, bool tweak)
{
std::pair<PumpMap::iterator, bool> inserted =
mPumpMap.insert(PumpMap::value_type(name, const_cast<LLEventPump*>(&pump)));
// If the insert worked, then the name is unique; return that.
if (inserted.second)
return name;
// Here the new entry was NOT inserted, and therefore name isn't unique.
// Unless we're permitted to tweak it, that's Bad.
if (! tweak)
{
throw LLEventPump::DupPumpName(std::string("Duplicate LLEventPump name '") + name + "'");
}
// The passed name isn't unique, but we're permitted to tweak it. Find the
// first decimal-integer suffix not already taken. The insert() attempt
// above will have set inserted.first to the iterator of the existing
// entry by that name. Starting there, walk forward until we reach an
// entry that doesn't start with 'name'. For each entry consisting of name
// + integer suffix, capture the integer suffix in a set. Use a set
// because we're going to encounter string suffixes in the order: name1,
// name10, name11, name2, ... Walking those possibilities in that order
// isn't convenient to detect the first available "hole."
std::set<int> suffixes;
PumpMap::iterator pmi(inserted.first), pmend(mPumpMap.end());
// We already know inserted.first references the existing entry with
// 'name' as the key; skip that one and start with the next.
while (++pmi != pmend)
{
if (pmi->first.substr(0, name.length()) != name)
{
// Found the first entry beyond the entries starting with 'name':
// stop looping.
break;
}
// Here we're looking at an entry that starts with 'name'. Is the rest
// of it an integer?
// Dubious (?) assumption: in the local character set, decimal digits
// are in increasing order such that '9' is the last of them. This
// test deals with 'name' values such as 'a', where there might be a
// very large number of entries starting with 'a' whose suffixes
// aren't integers. A secondary assumption is that digit characters
// precede most common name characters (true in ASCII, false in
// EBCDIC). The test below is correct either way, but it's worth more
// if the assumption holds.
if (pmi->first[name.length()] > '9')
break;
// It should be cheaper to detect that we're not looking at a digit
// character -- and therefore the suffix can't possibly be an integer
// -- than to attempt the lexical_cast and catch the exception.
if (! std::isdigit(pmi->first[name.length()]))
continue;
// Okay, the first character of the suffix is a digit, it's worth at
// least attempting to convert to int.
try
{
suffixes.insert(boost::lexical_cast<int>(pmi->first.substr(name.length())));
}
catch (const boost::bad_lexical_cast&)
{
// If the rest of pmi->first isn't an int, just ignore it.
}
}
// Here we've accumulated in 'suffixes' all existing int suffixes of the
// entries starting with 'name'. Find the first unused one.
int suffix = 1;
for ( ; suffixes.find(suffix) != suffixes.end(); ++suffix)
;
// Here 'suffix' is not in 'suffixes'. Construct a new name based on that
// suffix, insert it and return it.
std::ostringstream out;
out << name << suffix;
return registerNew(pump, out.str(), tweak);
}
void LLEventPumps::unregister(const LLEventPump& pump)
{
// Remove this instance from mPumpMap
PumpMap::iterator found = mPumpMap.find(pump.getName());
if (found != mPumpMap.end())
{
mPumpMap.erase(found);
}
// If this instance is one we created, also remove it from mOurPumps so we
// won't try again to delete it later!
PumpSet::iterator psfound = mOurPumps.find(const_cast<LLEventPump*>(&pump));
if (psfound != mOurPumps.end())
{
mOurPumps.erase(psfound);
}
}
//static
bool LLEventPumps::sDeleted;
//static
void LLEventPumps::maybe_unregister(const LLEventPump& pump)
{
if (!sDeleted)
{
LLEventPumps::instance().unregister(pump);
}
}
LLEventPumps::~LLEventPumps()
{
// Deleting an LLEventPump calls its destructor, which calls maybe_unregister(),
// which would try to remove that LLEventPump instance from a NEWLY created LLEventPumps
// singleton (as we're already being destructed). Therefore, mark that we're not
// home anymore... --Aleric
sDeleted = true;
// Subsequently we can delete every LLEventPump we instantiated (via obtain()).
// We're not clearing mPumpMap or mOurPumps here... their destructors will.
for (LLEventPumps::PumpSet::iterator pump = mOurPumps.begin(); pump != mOurPumps.end(); ++pump)
{
delete *pump;
}
}
/*****************************************************************************
* LLEventPump
*****************************************************************************/
#if LL_WINDOWS
#pragma warning (push)
#pragma warning (disable : 4355) // 'this' used in initializer list: yes, intentionally
#endif
LLEventPump::LLEventPump(const std::string& name, bool tweak):
// Register every new instance with LLEventPumps
mName(LLEventPumps::instance().registerNew(*this, name, tweak)),
mSignal(new LLStandardSignal()),
mEnabled(true)
{}
#if LL_WINDOWS
#pragma warning (pop)
#endif
LLEventPump::~LLEventPump()
{
// Unregister this doomed instance from LLEventPumps
LLEventPumps::maybe_unregister(*this);
}
// static data member
const LLEventPump::NameList LLEventPump::empty;
std::string LLEventPump::inventName(const std::string& pfx)
{
static long suffix = 0;
return STRINGIZE(pfx << suffix++);
}
void LLEventPump::reset()
{
mSignal.reset();
mConnections.clear();
//mDeps.clear();
}
LLBoundListener LLEventPump::listen_impl(const std::string& name, const LLEventListener& listener,
const NameList& after,
const NameList& before)
{
// Check for duplicate name before connecting listener to mSignal
ConnectionMap::const_iterator found = mConnections.find(name);
// In some cases the user might disconnect a connection explicitly -- or
// might use LLEventTrackable to disconnect implicitly. Either way, we can
// end up retaining in mConnections a zombie connection object that's
// already been disconnected. Such a connection object can't be
// reconnected -- nor, in the case of LLEventTrackable, would we want to
// try, since disconnection happens with the destruction of the listener
// object. That means it's safe to overwrite a disconnected connection
// object with the new one we're attempting. The case we want to prevent
// is only when the existing connection object is still connected.
if (found != mConnections.end() && found->second.connected())
{
throw DupListenerName(std::string("Attempt to register duplicate listener name '") + name +
"' on " + typeid(*this).name() + " '" + getName() + "'");
}
// Okay, name is unique, try to reconcile its dependencies. Specify a new
// "node" value that we never use for an mSignal placement; we'll fix it
// later.
DependencyMap::node_type& newNode = mDeps.add(name, -1.0, after, before);
// What if this listener has been added, removed and re-added? In that
// case newNode already has a non-negative value because we never remove a
// listener from mDeps. But keep processing uniformly anyway in case the
// listener was added back with different dependencies. Then mDeps.sort()
// would put it in a different position, and the old newNode placement
// value would be wrong, so we'd have to reassign it anyway. Trust that
// re-adding a listener with the same dependencies is the trivial case for
// mDeps.sort(): it can just replay its cache.
DependencyMap::sorted_range sorted_range;
try
{
// Can we pick an order that works including this new entry?
sorted_range = mDeps.sort();
}
catch (const DependencyMap::Cycle& e)
{
// No: the new node's after/before dependencies have made mDeps
// unsortable. If we leave the new node in mDeps, it will continue
// to screw up all future attempts to sort()! Pull it out.
mDeps.remove(name);
throw Cycle(std::string("New listener '") + name + "' on " + typeid(*this).name() +
" '" + getName() + "' would cause cycle: " + e.what());
}
// Walk the list to verify that we haven't changed the order.
float previous = 0.0, myprev = 0.0;
DependencyMap::sorted_iterator mydmi = sorted_range.end(); // need this visible after loop
for (DependencyMap::sorted_iterator dmi = sorted_range.begin();
dmi != sorted_range.end(); ++dmi)
{
// Since we've added the new entry with an invalid placement,
// recognize it and skip it.
if (dmi->first == name)
{
// Remember the iterator belonging to our new node, and which
// placement value was 'previous' at that point.
mydmi = dmi;
myprev = previous;
continue;
}
// If the new node has rearranged the existing nodes, we'll find
// that their placement values are no longer in increasing order.
if (dmi->second < previous)
{
// This is another scenario in which we'd better back out the
// newly-added node from mDeps -- but don't do it yet, we want to
// traverse the existing mDeps to report on it!
// Describe the change to the order of our listeners. Copy
// everything but the newest listener to a vector we can sort to
// obtain the old order.
typedef std::vector< std::pair<float, std::string> > SortNameList;
SortNameList sortnames;
for (DependencyMap::sorted_iterator cdmi(sorted_range.begin()), cdmend(sorted_range.end());
cdmi != cdmend; ++cdmi)
{
if (cdmi->first != name)
{
sortnames.push_back(SortNameList::value_type(cdmi->second, cdmi->first));
}
}
std::sort(sortnames.begin(), sortnames.end());
std::ostringstream out;
out << "New listener '" << name << "' on " << typeid(*this).name() << " '" << getName()
<< "' would move previous listener '" << dmi->first << "'\nwas: ";
SortNameList::const_iterator sni(sortnames.begin()), snend(sortnames.end());
if (sni != snend)
{
out << sni->second;
while (++sni != snend)
{
out << ", " << sni->second;
}
}
out << "\nnow: ";
DependencyMap::sorted_iterator ddmi(sorted_range.begin()), ddmend(sorted_range.end());
if (ddmi != ddmend)
{
out << ddmi->first;
while (++ddmi != ddmend)
{
out << ", " << ddmi->first;
}
}
// NOW remove the offending listener node.
mDeps.remove(name);
// Having constructed a description of the order change, inform caller.
throw OrderChange(out.str());
}
// This node becomes the previous one.
previous = dmi->second;
}
// We just got done with a successful mDeps.add(name, ...) call. We'd
// better have found 'name' somewhere in that sorted list!
assert(mydmi != sorted_range.end());
// Four cases:
// 0. name is the only entry: placement 1.0
// 1. name is the first of several entries: placement (next placement)/2
// 2. name is between two other entries: placement (myprev + (next placement))/2
// 3. name is the last entry: placement ceil(myprev) + 1.0
// Since we've cleverly arranged for myprev to be 0.0 if name is the
// first entry, this folds down to two cases. Case 1 is subsumed by
// case 2, and case 0 is subsumed by case 3. So we need only handle
// cases 2 and 3, which means we need only detect whether name is the
// last entry. Increment mydmi to see if there's anything beyond.
if (++mydmi != sorted_range.end())
{
// The new node isn't last. Place it between the previous node and
// the successor.
newNode = (myprev + mydmi->second)/2.0;
}
else
{
// The new node is last. Bump myprev up to the next integer, add
// 1.0 and use that.
newNode = std::ceil(myprev) + 1.0;
}
// Now that newNode has a value that places it appropriately in mSignal,
// connect it.
LLBoundListener bound = mSignal->connect(newNode, listener);
mConnections[name] = bound;
return bound;
}
LLBoundListener LLEventPump::getListener(const std::string& name) const
{
ConnectionMap::const_iterator found = mConnections.find(name);
if (found != mConnections.end())
{
return found->second;
}
// not found, return dummy LLBoundListener
return LLBoundListener();
}
void LLEventPump::stopListening(const std::string& name)
{
ConnectionMap::iterator found = mConnections.find(name);
if (found != mConnections.end())
{
found->second.disconnect();
mConnections.erase(found);
}
// We intentionally do NOT remove this name from mDeps. It may happen that
// the same listener with the same name and dependencies will jump on and
// off this LLEventPump repeatedly. Keeping a cache of dependencies will
// avoid a new dependency sort in such cases.
}
/*****************************************************************************
* LLEventStream
*****************************************************************************/
bool LLEventStream::post(const LLSD& event)
{
if (! mEnabled || !mSignal)
{
return false;
}
// NOTE NOTE NOTE: Any new access to member data beyond this point should
// cause us to move our LLStandardSignal object to a pimpl class along
// with said member data. Then the local shared_ptr will preserve both.
// DEV-43463: capture a local copy of mSignal. We've turned up a
// cross-coroutine scenario (described in the Jira) in which this post()
// call could end up destroying 'this', the LLEventPump subclass instance
// containing mSignal, during the call through *mSignal. So -- capture a
// *stack* instance of the shared_ptr, ensuring that our heap
// LLStandardSignal object will live at least until post() returns, even
// if 'this' gets destroyed during the call.
boost::shared_ptr<LLStandardSignal> signal(mSignal);
// Let caller know if any one listener handled the event. This is mostly
// useful when using LLEventStream as a listener for an upstream
// LLEventPump.
return (*signal)(event);
}
/*****************************************************************************
* LLEventQueue
*****************************************************************************/
bool LLEventQueue::post(const LLSD& event)
{
if (mEnabled)
{
// Defer sending this event by queueing it until flush()
mEventQueue.push_back(event);
}
// Unconditionally return false. We won't know until flush() whether a
// listener claims to have handled the event -- meanwhile, don't block
// other listeners.
return false;
}
void LLEventQueue::flush()
{
if(!mSignal) return;
// Consider the case when a given listener on this LLEventQueue posts yet
// another event on the same queue. If we loop over mEventQueue directly,
// we'll end up processing all those events during the same flush() call
// -- rather like an EventStream. Instead, copy mEventQueue and clear it,
// so that any new events posted to this LLEventQueue during flush() will
// be processed in the *next* flush() call.
EventQueue queue(mEventQueue);
mEventQueue.clear();
// NOTE NOTE NOTE: Any new access to member data beyond this point should
// cause us to move our LLStandardSignal object to a pimpl class along
// with said member data. Then the local shared_ptr will preserve both.
// DEV-43463: capture a local copy of mSignal. See LLEventStream::post()
// for detailed comments.
boost::shared_ptr<LLStandardSignal> signal(mSignal);
for ( ; ! queue.empty(); queue.pop_front())
{
(*signal)(queue.front());
}
}
/*****************************************************************************
* LLListenerOrPumpName
*****************************************************************************/
LLListenerOrPumpName::LLListenerOrPumpName(const std::string& pumpname):
// Look up the specified pumpname, and bind its post() method as our listener
mListener(boost::bind(&LLEventPump::post,
boost::ref(LLEventPumps::instance().obtain(pumpname)),
_1))
{
}
LLListenerOrPumpName::LLListenerOrPumpName(const char* pumpname):
// Look up the specified pumpname, and bind its post() method as our listener
mListener(boost::bind(&LLEventPump::post,
boost::ref(LLEventPumps::instance().obtain(pumpname)),
_1))
{
}
bool LLListenerOrPumpName::operator()(const LLSD& event) const
{
if (! mListener)
{
throw Empty("attempting to call uninitialized");
}
return (*mListener)(event);
}
void LLReqID::stamp(LLSD& response) const
{
if (! (response.isUndefined() || response.isMap()))
{
// If 'response' was previously completely empty, it's okay to
// turn it into a map. If it was already a map, then it should be
// okay to add a key. But if it was anything else (e.g. a scalar),
// assigning a ["reqid"] key will DISCARD the previous value,
// replacing it with a map. That would be Bad.
LL_INFOS("LLReqID") << "stamp(" << mReqid << ") leaving non-map response unmodified: "
<< response << LL_ENDL;
return;
}
LLSD oldReqid(response["reqid"]);
if (! (oldReqid.isUndefined() || llsd_equals(oldReqid, mReqid)))
{
LL_INFOS("LLReqID") << "stamp(" << mReqid << ") preserving existing [\"reqid\"] value "
<< oldReqid << " in response: " << response << LL_ENDL;
return;
}
response["reqid"] = mReqid;
}
bool sendReply(const LLSD& reply, const LLSD& request, const std::string& replyKey)
{
// If the original request has no value for replyKey, it's pointless to
// construct or send a reply event: on which LLEventPump should we send
// it? Allow that to be optional: if the caller wants to require replyKey,
// it can so specify when registering the operation method.
if (! request.has(replyKey))
{
return false;
}
// Here the request definitely contains replyKey; reasonable to proceed.
// Copy 'reply' to modify it.
LLSD newreply(reply);
// Get the ["reqid"] element from request
LLReqID reqID(request);
// and copy it to 'newreply'.
reqID.stamp(newreply);
// Send reply on LLEventPump named in request[replyKey]. Don't forget to
// send the modified 'newreply' instead of the original 'reply'.
return LLEventPumps::instance().obtain(request[replyKey]).post(newreply);
}