llcachename.cpp

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#include "linden_common.h"

#include "llcachename.h"

// linden library includes
#include "message.h"
#include "llrand.h"
#include "lldbstrings.h"
#include "llframetimer.h"
#include "llhost.h"
#include "lluuid.h"

// Constants
const char* CN_WAITING = "(waiting)";
const char* CN_NOBODY = "(nobody)";
const char* CN_NONE = "(none)";
const char* CN_HIPPOS = "(hippos)";
const F32 HIPPO_PROBABILITY = 0.01f;

// We track name requests in flight for up to this long.
// We won't re-request a name during this time
const U32 PENDING_TIMEOUT_SECS = 5 * 60;

// File version number
const S32 CN_FILE_VERSION = 2;

// Globals
LLCacheName* gCacheName = NULL;


class LLCacheNameEntry
{
public:
        LLCacheNameEntry();

public:
        bool mIsGroup;
        U32 mCreateTime;        // unix time_t
        char mFirstName[DB_FIRST_NAME_BUF_SIZE]; /*Flawfinder: ignore*/
        char mLastName[DB_LAST_NAME_BUF_SIZE]; /*Flawfinder: ignore*/
        char mGroupName[DB_GROUP_NAME_BUF_SIZE]; /*Flawfinder: ignore*/
};

LLCacheNameEntry::LLCacheNameEntry()
{
        mFirstName[0] = '\0';
        mLastName[0]  = '\0';
        mGroupName[0] = '\0';
}


class PendingReply
{
public:
        LLUUID                          mID;
        LLCacheNameCallback mCallback;
        LLHost                          mHost;
        void*                           mData;
        PendingReply(const LLUUID& id, LLCacheNameCallback callback, void* data = NULL)
                : mID(id), mCallback(callback), mData(data)
        { }

        PendingReply(const LLUUID& id, const LLHost& host)
                : mID(id), mCallback(0), mHost(host)
        { }

        void done()                     { mID.setNull(); }
        bool isDone() const     { return mID.isNull() != FALSE; }
};

class ReplySender
{
public:
        ReplySender(LLMessageSystem* msg);
        ~ReplySender();

        void send(const LLUUID& id,
                const LLCacheNameEntry& entry, const LLHost& host);

private:
        void flush();

        LLMessageSystem*        mMsg;
        bool                            mPending;
        bool                            mCurrIsGroup;
        LLHost                          mCurrHost;
};

ReplySender::ReplySender(LLMessageSystem* msg)
        : mMsg(msg), mPending(false)
{ }

ReplySender::~ReplySender()
{
        flush();
}

void ReplySender::send(const LLUUID& id,
        const LLCacheNameEntry& entry, const LLHost& host)
{
        if (mPending)
        {
                if (mCurrIsGroup != entry.mIsGroup
                ||  mCurrHost != host)
                {
                        flush();
                }
        }

        if (!mPending)
        {
                mPending = true;
                mCurrIsGroup = entry.mIsGroup;
                mCurrHost = host;

                if(mCurrIsGroup)
                        mMsg->newMessageFast(_PREHASH_UUIDGroupNameReply);
                else
                        mMsg->newMessageFast(_PREHASH_UUIDNameReply);
        }

        mMsg->nextBlockFast(_PREHASH_UUIDNameBlock);
        mMsg->addUUIDFast(_PREHASH_ID, id);
        if(mCurrIsGroup)
        {
                mMsg->addStringFast(_PREHASH_GroupName, entry.mGroupName);
        }
        else
        {
                mMsg->addStringFast(_PREHASH_FirstName, entry.mFirstName);
                mMsg->addStringFast(_PREHASH_LastName, entry.mLastName);
        }

        if(mMsg->isSendFullFast(_PREHASH_UUIDNameBlock))
        {
                flush();
        }
}

void ReplySender::flush()
{
        if (mPending)
        {
                mMsg->sendReliable(mCurrHost);
                mPending = false;
        }
}


typedef std::set<LLUUID>                                        AskQueue;
typedef std::vector<PendingReply>                       ReplyQueue;
typedef std::map<LLUUID,U32>                            PendingQueue;
typedef std::map<LLUUID, LLCacheNameEntry*> Cache;
typedef std::vector<LLCacheNameCallback>        Observers;

class LLCacheName::Impl
{
public:
        LLMessageSystem*        mMsg;
        LLHost                          mUpstreamHost;

        Cache                           mCache;
                // the map of UUIDs to names

        AskQueue                        mAskNameQueue;
        AskQueue                        mAskGroupQueue;
                // UUIDs to ask our upstream host about
        
        PendingQueue            mPendingQueue;
                // UUIDs that have been requested but are not in cache yet.

        ReplyQueue                      mReplyQueue;
                // requests awaiting replies from us

        Observers                       mObservers;

        LLFrameTimer            mProcessTimer;

        Impl(LLMessageSystem* msg);
        ~Impl();

        void processPendingAsks();
        void processPendingReplies();
        void sendRequest(const char* msg_name, const AskQueue& queue);
        bool isRequestPending(const LLUUID& id);

        // Message system callbacks.
        void processUUIDRequest(LLMessageSystem* msg, bool isGroup);
        void processUUIDReply(LLMessageSystem* msg, bool isGroup);

        static void handleUUIDNameRequest(LLMessageSystem* msg, void** userdata);
        static void handleUUIDNameReply(LLMessageSystem* msg, void** userdata);
        static void handleUUIDGroupNameRequest(LLMessageSystem* msg, void** userdata);
        static void handleUUIDGroupNameReply(LLMessageSystem* msg, void** userdata);

        void notifyObservers(const LLUUID& id, const char* first, const char* last, BOOL group);
};



LLCacheName::LLCacheName(LLMessageSystem* msg)
        : impl(* new Impl(msg))
        { }

LLCacheName::LLCacheName(LLMessageSystem* msg, const LLHost& upstream_host)
        : impl(* new Impl(msg))
{
        setUpstream(upstream_host);
}

LLCacheName::~LLCacheName()
{
        delete &impl;
}

LLCacheName::Impl::Impl(LLMessageSystem* msg)
        : mMsg(msg), mUpstreamHost(LLHost::invalid)
{
        mMsg->setHandlerFuncFast(
                _PREHASH_UUIDNameRequest, handleUUIDNameRequest, (void**)this);
        mMsg->setHandlerFuncFast(
                _PREHASH_UUIDNameReply, handleUUIDNameReply, (void**)this);
        mMsg->setHandlerFuncFast(
                _PREHASH_UUIDGroupNameRequest, handleUUIDGroupNameRequest, (void**)this);
        mMsg->setHandlerFuncFast(
                _PREHASH_UUIDGroupNameReply, handleUUIDGroupNameReply, (void**)this);
}


LLCacheName::Impl::~Impl()
{
        for_each(mCache.begin(), mCache.end(), DeletePairedPointer());
}


void LLCacheName::setUpstream(const LLHost& upstream_host)
{
        impl.mUpstreamHost = upstream_host;
}

void LLCacheName::addObserver(LLCacheNameCallback callback)
{
        impl.mObservers.push_back(callback);
}

void LLCacheName::removeObserver(LLCacheNameCallback callback)
{
        Observers::iterator it = impl.mObservers.begin();
        Observers::iterator end = impl.mObservers.end();

        for ( ; it != end; ++it)
        {
                const LLCacheNameCallback& cb = (*it);
                if (cb == callback)
                {
                        impl.mObservers.erase(it);
                        return;
                }
        }
}

void LLCacheName::cancelCallback(const LLUUID& id, LLCacheNameCallback callback, void* user_data)
{
        ReplyQueue::iterator it = impl.mReplyQueue.begin();
        ReplyQueue::iterator end = impl.mReplyQueue.end();
        
        for(; it != end; ++it)
        {
                const PendingReply& reply = (*it);

                if ((callback == reply.mCallback)
                        && (id == reply.mID)
                        && (user_data == reply.mData) )
                {
                        impl.mReplyQueue.erase(it);
                        return;
                }
        }
}

void LLCacheName::importFile(FILE* fp)
{
        S32 count = 0;

        const S32 BUFFER_SIZE = 1024;
        char buffer[BUFFER_SIZE];       /*Flawfinder: ignore*/

        // *NOTE: These buffer sizes are hardcoded into sscanf() below
        char id_string[MAX_STRING]; /*Flawfinder: ignore*/
        char firstname[MAX_STRING]; /*Flawfinder: ignore*/
        char lastname[MAX_STRING]; /*Flawfinder: ignore*/
        U32 create_time;

        // This is OK if the first line is actually a name.  We just don't load it.
        char* valid = fgets(buffer, BUFFER_SIZE, fp);
        if (!valid) return;

        // *NOTE: This buffer size is hardcoded into sscanf() below
        char version_string[BUFFER_SIZE]; /*Flawfinder: ignore*/
        S32 version = 0;
        S32 match = sscanf(     /* Flawfinder: ignore */
                buffer,
                "%1023s %d",
                version_string, &version);
        if (   match != 2
                || strcmp(version_string, "version")
                || version != CN_FILE_VERSION)
        {
                llwarns << "Ignoring old cache name file format" << llendl;
                return;
        }

        // We'll expire entries more than a week old
        U32 now = (U32)time(NULL);
        const U32 SECS_PER_DAY = 60 * 60 * 24;
        U32 delete_before_time = now - (7 * SECS_PER_DAY);

        while(!feof(fp))
        {
                valid = fgets(buffer, BUFFER_SIZE, fp);
                if (!valid) break;

                match = sscanf( /* Flawfinder: ignore */
                        buffer,
                        "%254s %u %254s %254s",
                        id_string, 
                        &create_time,
                        firstname, 
                        lastname);
                if (4 != match) continue;

                LLUUID id(id_string);
                if (id.isNull()) continue;

                // undo trivial XOR
                S32 i;
                for (i = 0; i < UUID_BYTES; i++)
                {
                        id.mData[i] ^= 0x33;
                }

                // Don't load entries that are more than a week old
                if (create_time < delete_before_time) continue;

                LLCacheNameEntry* entry = new LLCacheNameEntry();
                entry->mIsGroup = false;
                entry->mCreateTime = create_time;
                LLString::copy(entry->mFirstName, firstname, DB_FIRST_NAME_BUF_SIZE);
                LLString::copy(entry->mLastName, lastname, DB_LAST_NAME_BUF_SIZE);
                impl.mCache[id] = entry;

                count++;
        }

        llinfos << "LLCacheName loaded " << count << " names" << llendl;
}


void LLCacheName::exportFile(FILE* fp)
{
        fprintf(fp, "version\t%d\n", CN_FILE_VERSION);

        for (Cache::iterator iter = impl.mCache.begin(),
                         end = impl.mCache.end();
                 iter != end; iter++)
        {
                LLCacheNameEntry* entry = iter->second;
                // Only write entries for which we have valid data.
                // HACK: Only write agent names.  This makes the reader easier.
                if (   entry->mFirstName[0]
                        && entry->mLastName[0])
                {
                        LLUUID id = iter->first;

                        // Trivial XOR encoding
                        S32 i;
                        for (i = 0; i < UUID_BYTES; i++)
                        {
                                id.mData[i] ^= 0x33;
                        }

                        char id_string[UUID_STR_SIZE]; /*Flawfinder:ignore*/
                        id.toString(id_string);

                        // ...not a group name
                        fprintf(fp, "%s\t%u\t%s\t%s\n", 
                                        id_string, 
                                        entry->mCreateTime,
                                        entry->mFirstName, 
                                        entry->mLastName);
                }
        }
}


BOOL LLCacheName::getName(const LLUUID& id, char* first, char* last)
{
        if(id.isNull())
        {
                // The function signature needs to change to pass in the
                // length of first and last.
                strcpy(first, CN_NOBODY);       /*Flawfinder: ignore*/
                last[0] = '\0';
                return FALSE;
        }

        LLCacheNameEntry* entry = get_ptr_in_map(impl.mCache, id );
        if (entry)
        {
                // The function signature needs to change to pass in the
                // length of first and last.
                strcpy(first, entry->mFirstName);       /*Flawfinder: ignore*/
                strcpy(last,  entry->mLastName);        /*Flawfinder: ignore*/
                return TRUE;
        }
        else
        {
                //The function signature needs to change to pass in the
                //length of first and last.
                strcpy(first,(ll_frand() < HIPPO_PROBABILITY)
                                                ? CN_HIPPOS 
                                                : CN_WAITING);
                strcpy(last, "");       /*Flawfinder: ignore*/

                if (!impl.isRequestPending(id))
                {
                        impl.mAskNameQueue.insert(id);
                }       
                return FALSE;
        }

}



BOOL LLCacheName::getGroupName(const LLUUID& id, char* group)
{
        if(id.isNull())
        {
                // The function signature needs to change to pass in the
                // length of first and last.
                strcpy(group, CN_NONE); /*Flawfinder: ignore*/
                return FALSE;
        }

        LLCacheNameEntry* entry = get_ptr_in_map(impl.mCache,id);
        if (entry && !entry->mGroupName[0])
        {
                // COUNTER-HACK to combat James' HACK in exportFile()...
                // this group name was loaded from a name cache that did not
                // bother to save the group name ==> we must ask for it
                lldebugs << "LLCacheName queuing HACK group request: " << id << llendl;
                entry = NULL;
        }

        if (entry)
        {
                // The function signature needs to change to pass in the length
                // of group.
                strcpy(group, entry->mGroupName);       /*Flawfinder: ignore*/
                return TRUE;
        }
        else 
        {
                // The function signature needs to change to pass in the length
                // of first and last.
                strcpy(group, CN_WAITING);      /*Flawfinder: ignore*/
                if (!impl.isRequestPending(id))
                {
                        impl.mAskGroupQueue.insert(id);
                }
                return FALSE;
        }
}

// TODO: Make the cache name callback take a SINGLE std::string,
// not a separate first and last name.
void LLCacheName::get(const LLUUID& id, BOOL is_group, LLCacheNameCallback callback, void* user_data)
{
        if(id.isNull())
        {
                callback(id, CN_NOBODY, "", is_group, user_data);
        }

        LLCacheNameEntry* entry = get_ptr_in_map(impl.mCache, id );
        if (entry)
        {
                // id found in map therefore we can call the callback immediately.
                if (entry->mIsGroup)
                {
                        callback(id, entry->mGroupName, "", entry->mIsGroup, user_data);
                }
                else
                {
                        callback(id, entry->mFirstName, entry->mLastName, entry->mIsGroup, user_data);
                }
        }
        else
        {
                // id not found in map so we must queue the callback call until available.
                if (!impl.isRequestPending(id))
                {
                        if (is_group)
                        {
                                impl.mAskGroupQueue.insert(id);
                        }
                        else
                        {
                                impl.mAskNameQueue.insert(id);
                        }
                }
                impl.mReplyQueue.push_back(PendingReply(id, callback, user_data));
        }
}

void LLCacheName::processPending()
{
        const F32 SECS_BETWEEN_PROCESS = 0.1f;
        if(!impl.mProcessTimer.checkExpirationAndReset(SECS_BETWEEN_PROCESS))
        {
                return;
        }

        if(!impl.mUpstreamHost.isOk())
        {
                lldebugs << "LLCacheName::processPending() - bad upstream host."
                                 << llendl;
                return;
        }

        impl.processPendingAsks();
        impl.processPendingReplies();
}

void LLCacheName::deleteEntriesOlderThan(S32 secs)
{
        U32 now = (U32)time(NULL);
        U32 expire_time = now - secs;
        for(Cache::iterator iter = impl.mCache.begin(); iter != impl.mCache.end(); )
        {
                Cache::iterator curiter = iter++;
                LLCacheNameEntry* entry = curiter->second;
                if (entry->mCreateTime < expire_time)
                {
                        delete entry;
                        impl.mCache.erase(curiter);
                }
        }

        // These are pending requests that we never heard back from.
        U32 pending_expire_time = now - PENDING_TIMEOUT_SECS;
        for(PendingQueue::iterator p_iter = impl.mPendingQueue.begin();
                p_iter != impl.mPendingQueue.end(); )
        {
                PendingQueue::iterator p_curitor = p_iter++;
 
                if (p_curitor->second < pending_expire_time)
                {
                        impl.mPendingQueue.erase(p_curitor);
                }
        }
}


void LLCacheName::dump()
{
        for (Cache::iterator iter = impl.mCache.begin(),
                         end = impl.mCache.end();
                 iter != end; iter++)
        {
                LLCacheNameEntry* entry = iter->second;
                if (entry->mIsGroup)
                {
                        llinfos
                                << iter->first << " = (group) "
                                << entry->mGroupName
                                << " @ " << entry->mCreateTime
                                << llendl;
                }
                else
                {
                        llinfos
                                << iter->first << " = "
                                << entry->mFirstName << " " << entry->mLastName
                                << " @ " << entry->mCreateTime
                                << llendl;
                }
        }
}

void LLCacheName::dumpStats()
{
        llinfos << "Queue sizes: "
                        << " Cache=" << impl.mCache.size()
                        << " AskName=" << impl.mAskNameQueue.size()
                        << " AskGroup=" << impl.mAskGroupQueue.size()
                        << " Pending=" << impl.mPendingQueue.size()
                        << " Reply=" << impl.mReplyQueue.size()
                        << " Observers=" << impl.mObservers.size()
                        << llendl;
}

//static 
LLString LLCacheName::getDefaultName()
{
        return LLString(CN_WAITING);
}

void LLCacheName::Impl::processPendingAsks()
{
        sendRequest(_PREHASH_UUIDNameRequest, mAskNameQueue);
        sendRequest(_PREHASH_UUIDGroupNameRequest, mAskGroupQueue);
        mAskNameQueue.clear();
        mAskGroupQueue.clear();
}

void LLCacheName::Impl::processPendingReplies()
{
        ReplyQueue::iterator it = mReplyQueue.begin();
        ReplyQueue::iterator end = mReplyQueue.end();
        
        // First call all the callbacks, because they might send messages.
        for(; it != end; ++it)
        {
                LLCacheNameEntry* entry = get_ptr_in_map(mCache, it->mID);
                if(!entry) continue;

                if (it->mCallback)
                {
                        if (!entry->mIsGroup)
                        {
                                (it->mCallback)(it->mID,
                                        entry->mFirstName, entry->mLastName,
                                        FALSE, it->mData);
                        }
                        else {
                                (it->mCallback)(it->mID,
                                        entry->mGroupName, "",
                                        TRUE, it->mData);
                        }
                }
        }

        // Forward on all replies, if needed.
        ReplySender sender(mMsg);
        for (it = mReplyQueue.begin(); it != end; ++it)
        {
                LLCacheNameEntry* entry = get_ptr_in_map(mCache, it->mID);
                if(!entry) continue;

                if (it->mHost.isOk())
                {
                        sender.send(it->mID, *entry, it->mHost);
                }

                it->done();
        }

        mReplyQueue.erase(
                remove_if(mReplyQueue.begin(), mReplyQueue.end(),
                        std::mem_fun_ref(&PendingReply::isDone)),
                mReplyQueue.end());
}


void LLCacheName::Impl::sendRequest(
        const char* msg_name,
        const AskQueue& queue)
{
        if(queue.empty())
        {
                return;         
        }

        bool start_new_message = true;
        AskQueue::const_iterator it = queue.begin();
        AskQueue::const_iterator end = queue.end();
        for(; it != end; ++it)
        {
                if(start_new_message)
                {
                        start_new_message = false;
                        mMsg->newMessageFast(msg_name);
                }
                mMsg->nextBlockFast(_PREHASH_UUIDNameBlock);
                mMsg->addUUIDFast(_PREHASH_ID, (*it));

                if(mMsg->isSendFullFast(_PREHASH_UUIDNameBlock))
                {
                        start_new_message = true;
                        mMsg->sendReliable(mUpstreamHost);
                }
        }
        if(!start_new_message)
        {
                mMsg->sendReliable(mUpstreamHost);
        }
}

void LLCacheName::Impl::notifyObservers(const LLUUID& id,
        const char* first, const char* last, BOOL is_group)
{
        for (Observers::const_iterator i = mObservers.begin(),
                                                                   end = mObservers.end();
                i != end;
                ++i)
        {
                (**i)(id, first, last, is_group, NULL);
        }
}

bool LLCacheName::Impl::isRequestPending(const LLUUID& id)
{
        U32 now = (U32)time(NULL);
        U32 expire_time = now - PENDING_TIMEOUT_SECS;

        PendingQueue::iterator iter = mPendingQueue.find(id);

        if (iter == mPendingQueue.end()
                || (iter->second < expire_time) )
        {
                mPendingQueue[id] = now;
                return false;
        }

        return true;
}
        
void LLCacheName::Impl::processUUIDRequest(LLMessageSystem* msg, bool isGroup)
{
        // You should only get this message if the cache is at the simulator
        // level, hence having an upstream provider.
        if (!mUpstreamHost.isOk())
        {
                llwarns << "LLCacheName - got UUID name/group request, but no upstream provider!" << llendl;
                return;
        }

        LLHost fromHost = msg->getSender();
        ReplySender sender(msg);

        S32 count = msg->getNumberOfBlocksFast(_PREHASH_UUIDNameBlock);
        for(S32 i = 0; i < count; ++i)
        {
                LLUUID id;
                msg->getUUIDFast(_PREHASH_UUIDNameBlock, _PREHASH_ID, id, i);
                LLCacheNameEntry* entry = get_ptr_in_map(mCache, id);
                if(entry)
                {
                        if (isGroup != entry->mIsGroup)
                        {
                                llwarns << "LLCacheName - Asked for "
                                                << (isGroup ? "group" : "user") << " name, "
                                                << "but found "
                                                << (entry->mIsGroup ? "group" : "user")
                                                << ": " << id << llendl;
                        }
                        else
                        {
                                // ...it's in the cache, so send it as the reply
                                sender.send(id, *entry, fromHost);
                        }
                }
                else
                {
                        if (!isRequestPending(id))
                        {
                                if (isGroup)
                                {
                                        mAskGroupQueue.insert(id);
                                }
                                else
                                {
                                        mAskNameQueue.insert(id);
                                }
                        }
                        
                        mReplyQueue.push_back(PendingReply(id, fromHost));
                }
        }
}



void LLCacheName::Impl::processUUIDReply(LLMessageSystem* msg, bool isGroup)
{
        S32 count = msg->getNumberOfBlocksFast(_PREHASH_UUIDNameBlock);
        for(S32 i = 0; i < count; ++i)
        {
                LLUUID id;
                msg->getUUIDFast(_PREHASH_UUIDNameBlock, _PREHASH_ID, id, i);
                LLCacheNameEntry* entry = get_ptr_in_map(mCache, id);
                if (!entry)
                {
                        entry = new LLCacheNameEntry;
                        mCache[id] = entry;
                }

                mPendingQueue.erase(id);

                entry->mIsGroup = isGroup;
                entry->mCreateTime = (U32)time(NULL);
                if (!isGroup)
                {
                        msg->getStringFast(_PREHASH_UUIDNameBlock, _PREHASH_FirstName, DB_FIRST_NAME_BUF_SIZE, entry->mFirstName, i);
                        msg->getStringFast(_PREHASH_UUIDNameBlock, _PREHASH_LastName,  DB_LAST_NAME_BUF_SIZE, entry->mLastName, i);
                }
                else
                {
                        msg->getStringFast(_PREHASH_UUIDNameBlock, _PREHASH_GroupName, DB_GROUP_NAME_BUF_SIZE, entry->mGroupName, i);
                }

                if (!isGroup)
                {
                        notifyObservers(id,
                                                        entry->mFirstName, entry->mLastName,
                                                        FALSE);
                }
                else
                {
                        notifyObservers(id, entry->mGroupName, "", TRUE);
                }
        }
}



// static call back functions

void LLCacheName::Impl::handleUUIDNameReply(LLMessageSystem* msg, void** userData)
{
        ((LLCacheName::Impl*)userData)->processUUIDReply(msg, false);
}

void LLCacheName::Impl::handleUUIDNameRequest(LLMessageSystem* msg, void** userData)
{
        ((LLCacheName::Impl*)userData)->processUUIDRequest(msg, false);
}

void LLCacheName::Impl::handleUUIDGroupNameRequest(LLMessageSystem* msg, void** userData)
{
        ((LLCacheName::Impl*)userData)->processUUIDRequest(msg, true);
}

void LLCacheName::Impl::handleUUIDGroupNameReply(LLMessageSystem* msg, void** userData)
{
        ((LLCacheName::Impl*)userData)->processUUIDReply(msg, true);
}

---