Extend LLEventAPI to directly call other functions & methods.

Until now, LLEventAPI has only been able to register functions specifically
accepting(const LLSD&). Typically you add a wrapper method to your LLEventAPI
subclass, register that, have it extract desired params from the incoming LLSD
and then call the actual function of interest.
With help from Alain, added new LLEventAPI::add() methods capable of
registering functions/methods with arbitrary parameter signatures. The code
uses boost::fusion magic to implicitly match incoming LLSD arguments to the
function's formal parameter list, bypassing the need for an explicit helper
method.
New add() methods caused an ambiguity with a previous convenience overload.
Removed that overload and fixed the one existing usage.
Replaced LLEventDispatcher::get() with try_call() -- it's no longer easy to
return a Callable for caller to call directly. But the one known use of that
feature simply used it to avoid fatal LL_ERRS on unknown function-name string,
hence the try_call() approach actually addresses that case more directly.
Added indra/common/lleventdispatcher_test.cpp to exercise new functionality.

5 files changed, 1296 insertions, 66 deletions

diff --git a/indra/llcommon/CMakeLists.txt b/indra/llcommon/CMakeLists.txt
index 9342a22d46..dc9f93df3b 100644
--- a/indra/llcommon/CMakeLists.txt
+++ b/indra/llcommon/CMakeLists.txt
@@ -313,6 +313,7 @@ if (LL_TESTS)
   LL_ADD_INTEGRATION_TEST(lluri "" "${test_libs}")
   LL_ADD_INTEGRATION_TEST(reflection "" "${test_libs}")
   LL_ADD_INTEGRATION_TEST(stringize "" "${test_libs}")
+  LL_ADD_INTEGRATION_TEST(lleventdispatcher "" "${test_libs}")
 
   # *TODO - reenable these once tcmalloc libs no longer break the build.
   #ADD_BUILD_TEST(llallocator llcommon)
diff --git a/indra/llcommon/lleventdispatcher.cpp b/indra/llcommon/lleventdispatcher.cpp
index d6e820d793..2ab006a173 100644
--- a/indra/llcommon/lleventdispatcher.cpp
+++ b/indra/llcommon/lleventdispatcher.cpp
@@ -41,6 +41,326 @@
 #include "llevents.h"
 #include "llerror.h"
 #include "llsdutil.h"
+#include "stringize.h"
+#include <memory>                   // std::auto_ptr
+
+/*****************************************************************************
+*   LLSDArgsSource
+*****************************************************************************/
+/**
+ * Store an LLSD array, producing its elements one at a time. Die with LL_ERRS
+ * if the consumer requests more elements than the array contains.
+ */
+class LL_COMMON_API LLSDArgsSource
+{
+public:
+    LLSDArgsSource(const std::string function, const LLSD& args);
+    ~LLSDArgsSource();
+
+    LLSD next();
+
+    void done() const;
+
+private:
+    std::string _function;
+    LLSD _args;
+    LLSD::Integer _index;
+};
+
+LLSDArgsSource::LLSDArgsSource(const std::string function, const LLSD& args):
+    _function(function),
+    _args(args),
+    _index(0)
+{
+    if (! (_args.isUndefined() || _args.isArray()))
+    {
+        LL_ERRS("LLSDArgsSource") << _function << " needs an args array instead of "
+                                  << _args << LL_ENDL;
+    }
+}
+
+LLSDArgsSource::~LLSDArgsSource()
+{
+    done();
+}
+
+LLSD LLSDArgsSource::next()
+{
+    if (_index >= _args.size())
+    {
+        LL_ERRS("LLSDArgsSource") << _function << " requires more arguments than the "
+                                  << _args.size() << " provided: " << _args << LL_ENDL;
+    }
+    return _args[_index++];
+}
+
+void LLSDArgsSource::done() const
+{
+    if (_index < _args.size())
+    {
+        LL_WARNS("LLSDArgsSource") << _function << " only consumed " << _index
+                                   << " of the " << _args.size() << " arguments provided: "
+                                   << _args << LL_ENDL;
+    }
+}
+
+/*****************************************************************************
+*   LLSDArgsMapper
+*****************************************************************************/
+/**
+ * From a formal parameters description and a map of arguments, construct an
+ * arguments array.
+ *
+ * That is, given:
+ * - an LLSD array of length n containing parameter-name strings,
+ *   corresponding to the arguments of a function of interest
+ * - an LLSD collection specifying default parameter values, either:
+ *   - an LLSD array of length m <= n, matching the rightmost m params, or
+ *   - an LLSD map explicitly stating default name=value pairs
+ * - an LLSD map of parameter names and actual values for a particular
+ *   function call
+ * construct an LLSD array of actual argument values for this function call.
+ *
+ * The parameter-names array and the defaults collection describe the function
+ * being called. The map might vary with every call, providing argument values
+ * for the described parameters.
+ *
+ * The array of parameter names must match the number of parameters expected
+ * by the function of interest.
+ *
+ * If you pass a map of default parameter values, it provides default values
+ * as you might expect. It is an error to specify a default value for a name
+ * not listed in the parameters array.
+ *
+ * If you pass an array of default parameter values, it is mapped to the
+ * rightmost m of the n parameter names. It is an error if the default-values
+ * array is longer than the parameter-names array. Consider the following
+ * parameter names: ["a", "b", "c", "d"].
+ *
+ * - An empty array of default values (or an isUndefined() value) asserts that
+ *   every one of the above parameter names is required.
+ * - An array of four default values [1, 2, 3, 4] asserts that every one of
+ *   the above parameters is optional. If the current parameter map is empty,
+ *   they will be passed to the function as [1, 2, 3, 4].
+ * - An array of two default values [11, 12] asserts that parameters "a" and
+ *   "b" are required, while "c" and "d" are optional, having default values
+ *   "c"=11 and "d"=12.
+ *
+ * The arguments array is constructed as follows:
+ *
+ * - Arguments-map keys not found in the parameter-names array are ignored.
+ * - Entries from the map provide values for an improper subset of the
+ *   parameters named in the parameter-names array. This results in a
+ *   tentative values array with "holes." (size of map) + (number of holes) =
+ *   (size of names array)
+ * - Holes are filled with the default values.
+ * - Any remaining holes constitute an error.
+ */
+class LL_COMMON_API LLSDArgsMapper
+{
+public:
+    /// Accept description of function: function name, param names, param
+    /// default values
+    LLSDArgsMapper(const std::string& function, const LLSD& names, const LLSD& defaults);
+
+    /// Given arguments map, return LLSD::Array of parameter values, or LL_ERRS.
+    LLSD map(const LLSD& argsmap) const;
+
+private:
+    static std::string formatlist(const LLSD&);
+
+    // The function-name string is purely descriptive. We want error messages
+    // to be able to indicate which function's LLSDArgsMapper has the problem.
+    std::string _function;
+    // Store the names array pretty much as given.
+    LLSD _names;
+    // Though we're handed an array of name strings, it's more useful to us to
+    // store it as a map from name string to position index. Of course that's
+    // easy to generate from the incoming names array, but why do it more than
+    // once?
+    typedef std::map<LLSD::String, LLSD::Integer> IndexMap;
+    IndexMap _indexes;
+    // Generated array of default values, aligned with the array of param names.
+    LLSD _defaults;
+    // Indicate whether we have a default value for each param.
+    typedef std::vector<char> FilledVector;
+    FilledVector _has_dft;
+};
+
+LLSDArgsMapper::LLSDArgsMapper(const std::string& function,
+                               const LLSD& names, const LLSD& defaults):
+    _function(function),
+    _names(names),
+    _has_dft(names.size())
+{
+    if (! (_names.isUndefined() || _names.isArray()))
+    {
+        LL_ERRS("LLSDArgsMapper") << function << " names must be an array, not " << names << LL_ENDL;
+    }
+    LLSD::Integer nparams(_names.size());
+    // From _names generate _indexes.
+    for (LLSD::Integer ni = 0, nend = _names.size(); ni < nend; ++ni)
+    {
+        _indexes[_names[ni]] = ni;
+    }
+
+    // Presize _defaults() array so we don't have to resize it more than once.
+    // All entries are initialized to LLSD(); but since _has_dft is still all
+    // 0, they're all "holes" for now.
+    if (nparams)
+    {
+        _defaults[nparams - 1] = LLSD();
+    }
+
+    if (defaults.isUndefined() || defaults.isArray())
+    {
+        LLSD::Integer ndefaults = defaults.size();
+        // defaults is a (possibly empty) array. Right-align it with names.
+        if (ndefaults > nparams)
+        {
+            LL_ERRS("LLSDArgsMapper") << function << " names array " << names
+                                      << " shorter than defaults array " << defaults << LL_ENDL;
+        }
+
+        // Offset by which we slide defaults array right to right-align with
+        // _names array
+        LLSD::Integer offset = nparams - ndefaults;
+        // Fill rightmost _defaults entries from defaults, and mark them as
+        // filled
+        for (LLSD::Integer i = 0, iend = ndefaults; i < iend; ++i)
+        {
+            _defaults[i + offset] = defaults[i];
+            _has_dft[i + offset] = 1;
+        }
+    }
+    else if (defaults.isMap())
+    {
+        // defaults is a map. Use it to populate the _defaults array.
+        LLSD bogus;
+        for (LLSD::map_const_iterator mi(defaults.beginMap()), mend(defaults.endMap());
+             mi != mend; ++mi)
+        {
+            IndexMap::const_iterator ixit(_indexes.find(mi->first));
+            if (ixit == _indexes.end())
+            {
+                bogus.append(mi->first);
+                continue;
+            }
+
+            LLSD::Integer pos = ixit->second;
+            // Store default value at that position in the _defaults array.
+            _defaults[pos] = mi->second;
+            // Don't forget to record the fact that we've filled this
+            // position.
+            _has_dft[pos] = 1;
+        }
+        if (bogus.size())
+        {
+            LL_ERRS("LLSDArgsMapper") << function << " defaults specified for nonexistent params "
+                                      << formatlist(bogus) << LL_ENDL;
+        }
+    }
+    else
+    {
+        LL_ERRS("LLSDArgsMapper") << function << " defaults must be a map or an array, not "
+                                  << defaults << LL_ENDL;
+    }
+}
+
+LLSD LLSDArgsMapper::map(const LLSD& argsmap) const
+{
+    if (! (argsmap.isUndefined() || argsmap.isMap()))
+    {
+        LL_ERRS("LLSDArgsMapper") << _function << " map() needs a map, not " << argsmap << LL_ENDL;
+    }
+    // Initialize the args array. Indexing a non-const LLSD array grows it
+    // to appropriate size, but we don't want to resize this one on each
+    // new operation. Just make it as big as we need before we start
+    // stuffing values into it.
+    LLSD args(LLSD::emptyArray());
+    if (_defaults.size() == 0)
+    {
+        // If this function requires no arguments, fast exit. (Don't try to
+        // assign to args[-1].)
+        return args;
+    }
+    args[_defaults.size() - 1] = LLSD();
+
+    // Get a vector of chars to indicate holes. It's tempting to just scan
+    // for LLSD::isUndefined() values after filling the args array from
+    // the map, but it's plausible for caller to explicitly pass
+    // isUndefined() as the value of some parameter name. That's legal
+    // since isUndefined() has well-defined conversions (default value)
+    // for LLSD data types. So use a whole separate array for detecting
+    // holes. (Avoid std::vector<bool> which is known to be odd -- can we
+    // iterate?)
+    FilledVector filled(args.size());
+    // Walk the map.
+    for (LLSD::map_const_iterator mi(argsmap.beginMap()), mend(argsmap.endMap());
+         mi != mend; ++mi)
+    {
+        // mi->first is a parameter-name string, with mi->second its
+        // value. Look up the name's position index in _indexes.
+        IndexMap::const_iterator ixit(_indexes.find(mi->first));
+        if (ixit == _indexes.end())
+        {
+            // Allow for a map containing more params than were passed in
+            // our names array. Caller typically receives a map containing
+            // the function name, cruft such as reqid, etc. Ignore keys
+            // not defined in _indexes.
+            LL_DEBUGS("LLSDArgsMapper") << _function << " ignoring "
+                                        << mi->first << "=" << mi->second << LL_ENDL;
+            continue;
+        }
+        LLSD::Integer pos = ixit->second;
+        // Store the value at that position in the args array.
+        args[pos] = mi->second;
+        // Don't forget to record the fact that we've filled this
+        // position.
+        filled[pos] = 1;
+    }
+    // Fill any remaining holes from _defaults.
+    LLSD unfilled(LLSD::emptyArray());
+    for (LLSD::Integer i = 0, iend = args.size(); i < iend; ++i)
+    {
+        if (! filled[i])
+        {
+            // If there's no default value for this parameter, that's an
+            // error.
+            if (! _has_dft[i])
+            {
+                unfilled.append(_names[i]);
+            }
+            else
+            {
+                args[i] = _defaults[i];
+            }
+        }
+    }
+    // If any required args -- args without defaults -- were left unfilled
+    // by argsmap, that's a problem.
+    if (unfilled.size())
+    {
+        LL_ERRS("LLSDArgsMapper") << _function << " missing required arguments "
+                                  << formatlist(unfilled) << " from " << argsmap << LL_ENDL;
+    }
+
+    // done
+    return args;
+}
+
+std::string LLSDArgsMapper::formatlist(const LLSD& list)
+{
+    std::ostringstream out;
+    const char* delim = "";
+    for (LLSD::array_const_iterator li(list.beginArray()), lend(list.endArray());
+         li != lend; ++li)
+    {
+        out << delim << li->asString();
+        delim = ", ";
+    }
+    return out.str();
+}
 
 LLEventDispatcher::LLEventDispatcher(const std::string& desc, const std::string& key):
     mDesc(desc),
@@ -52,12 +372,178 @@ LLEventDispatcher::~LLEventDispatcher()
 {
 }
 
+/**
+ * DispatchEntry subclass used for callables accepting(const LLSD&)
+ */
+struct LLEventDispatcher::LLSDDispatchEntry: public LLEventDispatcher::DispatchEntry
+{
+    LLSDDispatchEntry(const std::string& desc, const Callable& func, const LLSD& required):
+        DispatchEntry(desc),
+        mFunc(func),
+        mRequired(required)
+    {}
+
+    Callable mFunc;
+    LLSD mRequired;
+
+    virtual void call(const std::string& desc, const LLSD& event) const
+    {
+        // Validate the syntax of the event itself.
+        std::string mismatch(llsd_matches(mRequired, event));
+        if (! mismatch.empty())
+        {
+            LL_ERRS("LLEventDispatcher") << desc << ": bad request: " << mismatch << LL_ENDL;
+        }
+        // Event syntax looks good, go for it!
+        mFunc(event);
+    }
+
+    virtual LLSD addMetadata(LLSD meta) const
+    {
+        meta["required"] = mRequired;
+        return meta;
+    }
+};
+
+/**
+ * DispatchEntry subclass for passing LLSD to functions accepting
+ * arbitrary argument types (convertible via LLSDParam)
+ */
+struct LLEventDispatcher::ParamsDispatchEntry: public LLEventDispatcher::DispatchEntry
+{
+    ParamsDispatchEntry(const std::string& desc, const invoker_function& func):
+        DispatchEntry(desc),
+        mInvoker(func)
+    {}
+
+    invoker_function mInvoker;
+
+    virtual void call(const std::string& desc, const LLSD& event) const
+    {
+        LLSDArgsSource src(desc, event);
+        mInvoker(boost::bind(&LLSDArgsSource::next, boost::ref(src)));
+    }
+};
+
+/**
+ * DispatchEntry subclass for dispatching LLSD::Array to functions accepting
+ * arbitrary argument types (convertible via LLSDParam)
+ */
+struct LLEventDispatcher::ArrayParamsDispatchEntry: public LLEventDispatcher::ParamsDispatchEntry
+{
+    ArrayParamsDispatchEntry(const std::string& desc, const invoker_function& func,
+                             LLSD::Integer arity):
+        ParamsDispatchEntry(desc, func),
+        mArity(arity)
+    {}
+
+    LLSD::Integer mArity;
+
+    virtual LLSD addMetadata(LLSD meta) const
+    {
+        LLSD array(LLSD::emptyArray());
+        // Resize to number of arguments required
+        array[mArity - 1] = LLSD();
+        llassert_always(array.size() == mArity);
+        meta["required"] = array;
+        return meta;
+    }
+};
+
+/**
+ * DispatchEntry subclass for dispatching LLSD::Map to functions accepting
+ * arbitrary argument types (convertible via LLSDParam)
+ */
+struct LLEventDispatcher::MapParamsDispatchEntry: public LLEventDispatcher::ParamsDispatchEntry
+{
+    MapParamsDispatchEntry(const std::string& name, const std::string& desc,
+                           const invoker_function& func,
+                           const LLSD& params, const LLSD& defaults):
+        ParamsDispatchEntry(desc, func),
+        mMapper(name, params, defaults),
+        mRequired(LLSD::emptyMap())
+    {
+        // Build the set of all param keys, then delete the ones that are
+        // optional. What's left are the ones that are required.
+        for (LLSD::array_const_iterator pi(params.beginArray()), pend(params.endArray());
+             pi != pend; ++pi)
+        {
+            mRequired[pi->asString()] = LLSD();
+        }
+
+        if (defaults.isArray() || defaults.isUndefined())
+        {
+            // Right-align the params and defaults arrays.
+            LLSD::Integer offset = params.size() - defaults.size();
+            // Now the name of every defaults[i] is at params[i + offset].
+            for (LLSD::Integer i(0), iend(defaults.size()); i < iend; ++i)
+            {
+                // Erase this optional param from mRequired.
+                mRequired.erase(params[i + offset].asString());
+                // Instead, make an entry in mOptional with the default
+                // param's name and value.
+                mOptional[params[i + offset].asString()] = defaults[i];
+            }
+        }
+        else if (defaults.isMap())
+        {
+            // if defaults is already a map, then it's already in the form we
+            // intend to deliver in metadata
+            mOptional = defaults;
+            // Just delete from mRequired every key appearing in mOptional.
+            for (LLSD::map_const_iterator mi(mOptional.beginMap()), mend(mOptional.endMap());
+                 mi != mend; ++mi)
+            {
+                mRequired.erase(mi->first);
+            }
+        }
+    }
+
+    LLSDArgsMapper mMapper;
+    LLSD mRequired;
+    LLSD mOptional;
+
+    virtual void call(const std::string& desc, const LLSD& event) const
+    {
+        // Just convert from LLSD::Map to LLSD::Array using mMapper, then pass
+        // to base-class call() method.
+        ParamsDispatchEntry::call(desc, mMapper.map(event));
+    }
+
+    virtual LLSD addMetadata(LLSD meta) const
+    {
+        meta["required"] = mRequired;
+        meta["optional"] = mOptional;
+        return meta;
+    }
+};
+
+void LLEventDispatcher::addArrayParamsDispatchEntry(const std::string& name,
+                                                    const std::string& desc,
+                                                    const invoker_function& invoker,
+                                                    LLSD::Integer arity)
+{
+    // Peculiar to me that boost::ptr_map() accepts std::auto_ptr but not dumb ptr
+    mDispatch.insert(name, std::auto_ptr<DispatchEntry>(
+                         new ArrayParamsDispatchEntry(desc, invoker, arity)));
+}
+
+void LLEventDispatcher::addMapParamsDispatchEntry(const std::string& name,
+                                                  const std::string& desc,
+                                                  const invoker_function& invoker,
+                                                  const LLSD& params,
+                                                  const LLSD& defaults)
+{
+    mDispatch.insert(name, std::auto_ptr<DispatchEntry>(
+                         new MapParamsDispatchEntry(name, desc, invoker, params, defaults)));
+}
+
 /// Register a callable by name
 void LLEventDispatcher::add(const std::string& name, const std::string& desc,
                             const Callable& callable, const LLSD& required)
 {
-    mDispatch.insert(DispatchMap::value_type(name,
-                                             DispatchMap::mapped_type(callable, desc, required)));
+    mDispatch.insert(name, std::auto_ptr<DispatchEntry>(
+                         new LLSDDispatchEntry(desc, callable, required)));
 }
 
 void LLEventDispatcher::addFail(const std::string& name, const std::string& classname) const
@@ -83,7 +569,7 @@ bool LLEventDispatcher::remove(const std::string& name)
 /// such callable exists, die with LL_ERRS.
 void LLEventDispatcher::operator()(const std::string& name, const LLSD& event) const
 {
-    if (! attemptCall(name, event))
+    if (! try_call(name, event))
     {
         LL_ERRS("LLEventDispatcher") << "LLEventDispatcher(" << mDesc << "): '" << name
                                      << "' not found" << LL_ENDL;
@@ -98,44 +584,29 @@ void LLEventDispatcher::operator()(const LLSD& event) const
     // This could/should be implemented in terms of the two-arg overload.
     // However -- we can produce a more informative error message.
     std::string name(event[mKey]);
-    if (! attemptCall(name, event))
+    if (! try_call(name, event))
     {
         LL_ERRS("LLEventDispatcher") << "LLEventDispatcher(" << mDesc << "): bad " << mKey
                                      << " value '" << name << "'" << LL_ENDL;
     }
 }
 
-bool LLEventDispatcher::attemptCall(const std::string& name, const LLSD& event) const
+bool LLEventDispatcher::try_call(const LLSD& event) const
 {
-    DispatchMap::const_iterator found = mDispatch.find(name);
-    if (found == mDispatch.end())
-    {
-        // The reason we only return false, leaving it up to our caller to die
-        // with LL_ERRS, is that different callers have different amounts of
-        // available information.
-        return false;
-    }
-    // Found the name, so it's plausible to even attempt the call. But first,
-    // validate the syntax of the event itself.
-    std::string mismatch(llsd_matches(found->second.mRequired, event));
-    if (! mismatch.empty())
-    {
-        LL_ERRS("LLEventDispatcher") << "LLEventDispatcher(" << mDesc << ") calling '" << name
-                                     << "': bad request: " << mismatch << LL_ENDL;
-    }
-    // Event syntax looks good, go for it!
-    (found->second.mFunc)(event);
-    return true;                    // tell caller we were able to call
+    return try_call(event[mKey], event);
 }
 
-LLEventDispatcher::Callable LLEventDispatcher::get(const std::string& name) const
+bool LLEventDispatcher::try_call(const std::string& name, const LLSD& event) const
 {
     DispatchMap::const_iterator found = mDispatch.find(name);
     if (found == mDispatch.end())
     {
-        return Callable();
+        return false;
     }
-    return found->second.mFunc;
+    // Found the name, so it's plausible to even attempt the call.
+    found->second->call(STRINGIZE("LLEventDispatcher(" << mDesc << ") calling '" << name << "'"),
+                        event);
+    return true;                    // tell caller we were able to call
 }
 
 LLSD LLEventDispatcher::getMetadata(const std::string& name) const
@@ -147,9 +618,8 @@ LLSD LLEventDispatcher::getMetadata(const std::string& name) const
     }
     LLSD meta;
     meta["name"] = name;
-    meta["desc"] = found->second.mDesc;
-    meta["required"] = found->second.mRequired;
-    return meta;
+    meta["desc"] = found->second->mDesc;
+    return found->second->addMetadata(meta);
 }
 
 LLDispatchListener::LLDispatchListener(const std::string& pumpname, const std::string& key):
@@ -164,3 +634,8 @@ bool LLDispatchListener::process(const LLSD& event)
     (*this)(event);
     return false;
 }
+
+LLEventDispatcher::DispatchEntry::DispatchEntry(const std::string& desc):
+    mDesc(desc)
+{}
+
diff --git a/indra/llcommon/lleventdispatcher.h b/indra/llcommon/lleventdispatcher.h
index dfffd59eb6..ce0fc7b585 100644
--- a/indra/llcommon/lleventdispatcher.h
+++ b/indra/llcommon/lleventdispatcher.h
@@ -27,18 +27,56 @@
  * 
  * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
  * $/LicenseInfo$
+ *
+ * The invoker machinery that constructs a boost::fusion argument list for use
+ * with boost::fusion::invoke() is derived from
+ * http://www.boost.org/doc/libs/1_45_0/libs/function_types/example/interpreter.hpp
+ * whose license information is copied below:
+ *
+ * "(C) Copyright Tobias Schwinger
+ *
+ * Use modification and distribution are subject to the boost Software License,
+ * Version 1.0. (See http://www.boost.org/LICENSE_1_0.txt)."
  */
 
 #if ! defined(LL_LLEVENTDISPATCHER_H)
 #define LL_LLEVENTDISPATCHER_H
 
+// nil is too generic a term to be allowed to be a global macro. In
+// particular, boost::fusion defines a 'class nil' (properly encapsulated in a
+// namespace) that a global 'nil' macro breaks badly.
+#if defined(nil)
+// Capture the value of the macro 'nil', hoping int is an appropriate type.
+static const int nil_(nil);
+// Now forget the macro.
+#undef nil
+// Finally, reintroduce 'nil' as a properly-scoped alias for the previously-
+// defined const 'nil_'. Make it static since otherwise it produces duplicate-
+// symbol link errors later.
+static const int& nil(nil_);
+#endif
+
 #include <string>
-#include <map>
+#include <boost/ptr_container/ptr_map.hpp>
 #include <boost/function.hpp>
 #include <boost/bind.hpp>
 #include <boost/iterator/transform_iterator.hpp>
+#include <boost/utility/enable_if.hpp>
+#include <boost/function_types/is_nonmember_callable_builtin.hpp>
+#include <boost/function_types/parameter_types.hpp>
+#include <boost/function_types/function_arity.hpp>
+#include <boost/type_traits/remove_cv.hpp>
+#include <boost/type_traits/remove_reference.hpp>
+#include <boost/fusion/include/push_back.hpp>
+#include <boost/fusion/include/cons.hpp>
+#include <boost/fusion/include/invoke.hpp>
+#include <boost/mpl/begin.hpp>
+#include <boost/mpl/end.hpp>
+#include <boost/mpl/next.hpp>
+#include <boost/mpl/deref.hpp>
 #include <typeinfo>
 #include "llevents.h"
+#include "llsdutil.h"
 
 class LLSD;
 
@@ -54,12 +92,18 @@ public:
     LLEventDispatcher(const std::string& desc, const std::string& key);
     virtual ~LLEventDispatcher();
 
-    /// Accept any C++ callable, typically a boost::bind() expression
+    /// @name Register functions accepting(const LLSD&)
+    //@{
+
+    /// Accept any C++ callable with the right signature, typically a
+    /// boost::bind() expression
     typedef boost::function<void(const LLSD&)> Callable;
 
     /**
-     * Register a @a callable by @a name. The optional @a required parameter
-     * is used to validate the structure of each incoming event (see
+     * Register a @a callable by @a name. The passed @a callable accepts a
+     * single LLSD value and uses it in any way desired, e.g. extract
+     * parameters and call some other function. The optional @a required
+     * parameter is used to validate the structure of each incoming event (see
      * llsd_matches()).
      */
     void add(const std::string& name,
@@ -69,8 +113,9 @@ public:
 
     /**
      * Special case: a subclass of this class can pass an unbound member
-     * function pointer without explicitly specifying the
-     * <tt>boost::bind()</tt> expression.
+     * function pointer (of an LLEventDispatcher subclass) without explicitly
+     * specifying the <tt>boost::bind()</tt> expression. The passed @a method
+     * accepts a single LLSD value, presumably containing other parameters.
      */
     template <class CLASS>
     void add(const std::string& name,
@@ -81,7 +126,8 @@ public:
         addMethod<CLASS>(name, desc, method, required);
     }
 
-    /// Overload for both const and non-const methods
+    /// Overload for both const and non-const methods. The passed @a method
+    /// accepts a single LLSD value, presumably containing other parameters.
     template <class CLASS>
     void add(const std::string& name,
              const std::string& desc,
@@ -91,8 +137,10 @@ public:
         addMethod<CLASS>(name, desc, method, required);
     }
 
+/*==========================================================================*|
     /// Convenience: for LLEventDispatcher, not every callable needs a
-    /// documentation string.
+    /// documentation string. The passed @a callable accepts a single LLSD
+    /// value, presumably containing other parameters.
     template <typename CALLABLE>
     void add(const std::string& name,
              CALLABLE callable,
@@ -100,6 +148,92 @@ public:
     {
         add(name, "", callable, required);
     }
+|*==========================================================================*/
+
+    //@}
+
+    /// @name Register functions with arbitrary param lists
+    //@{
+
+    /**
+     * Register a free function with arbitrary parameters. (This also works
+     * for static class methods.)
+     *
+     * When calling this name, pass an LLSD::Array. Each entry in turn will be
+     * converted to the corresponding parameter type using LLSDParam.
+     */
+    template<typename Function>
+    typename boost::enable_if< boost::function_types::is_nonmember_callable_builtin<Function>
+                               >::type add(const std::string& name,
+                                           const std::string& desc,
+                                           Function f);
+
+    /**
+     * Register a nonstatic class method with arbitrary parameters.
+     *
+     * To cover cases such as a method on an LLSingleton we don't yet want to
+     * instantiate, instead of directly storing an instance pointer, accept a
+     * nullary callable returning a pointer/reference to the desired class
+     * instance. If you already have an instance in hand,
+     * boost::lambda::var(instance) or boost::lambda::constant(instance_ptr)
+     * produce suitable callables.
+     *
+     * When calling this name, pass an LLSD::Array. Each entry in turn will be
+     * converted to the corresponding parameter type using LLSDParam.
+     */
+    template<typename Method, typename InstanceGetter>
+    typename boost::enable_if< boost::function_types::is_member_function_pointer<Method>
+                               >::type add(const std::string& name,
+                                           const std::string& desc,
+                                           Method f,
+                                           const InstanceGetter& getter);
+
+    /**
+     * Register a free function with arbitrary parameters. (This also works
+     * for static class methods.)
+     *
+     * Pass an LLSD::Array of parameter names, and optionally another
+     * LLSD::Array of default parameter values, a la LLSDArgsMapper.
+     *
+     * When calling this name, pass an LLSD::Map. We will internally generate
+     * an LLSD::Array using LLSDArgsMapper and then convert each entry in turn
+     * to the corresponding parameter type using LLSDParam.
+     */
+    template<typename Function>
+    typename boost::enable_if< boost::function_types::is_nonmember_callable_builtin<Function>
+                               >::type add(const std::string& name,
+                                           const std::string& desc,
+                                           Function f,
+                                           const LLSD& params,
+                                           const LLSD& defaults=LLSD());
+
+    /**
+     * Register a nonstatic class method with arbitrary parameters.
+     *
+     * To cover cases such as a method on an LLSingleton we don't yet want to
+     * instantiate, instead of directly storing an instance pointer, accept a
+     * nullary callable returning a pointer/reference to the desired class
+     * instance. If you already have an instance in hand,
+     * boost::lambda::var(instance) or boost::lambda::constant(instance_ptr)
+     * produce suitable callables.
+     *
+     * Pass an LLSD::Array of parameter names, and optionally another
+     * LLSD::Array of default parameter values, a la LLSDArgsMapper.
+     *
+     * When calling this name, pass an LLSD::Map. We will internally generate
+     * an LLSD::Array using LLSDArgsMapper and then convert each entry in turn
+     * to the corresponding parameter type using LLSDParam.
+     */
+    template<typename Method, typename InstanceGetter>
+    typename boost::enable_if< boost::function_types::is_member_function_pointer<Method>
+                               >::type add(const std::string& name,
+                                           const std::string& desc,
+                                           Method f,
+                                           const InstanceGetter& getter,
+                                           const LLSD& params,
+                                           const LLSD& defaults=LLSD());
+
+    //@}    
 
     /// Unregister a callable
     bool remove(const std::string& name);
@@ -109,12 +243,25 @@ public:
     /// the @a required prototype specified at add() time, die with LL_ERRS.
     void operator()(const std::string& name, const LLSD& event) const;
 
+    /// Call a registered callable with an explicitly-specified name and
+    /// return <tt>true</tt>. If no such callable exists, return
+    /// <tt>false</tt>. If the @a event fails to match the @a required
+    /// prototype specified at add() time, die with LL_ERRS.
+    bool try_call(const std::string& name, const LLSD& event) const;
+
     /// Extract the @a key value from the incoming @a event, and call the
     /// callable whose name is specified by that map @a key. If no such
     /// callable exists, die with LL_ERRS. If the @a event fails to match the
     /// @a required prototype specified at add() time, die with LL_ERRS.
     void operator()(const LLSD& event) const;
 
+    /// Extract the @a key value from the incoming @a event, call the callable
+    /// whose name is specified by that map @a key and return <tt>true</tt>.
+    /// If no such callable exists, return <tt>false</tt>. If the @a event
+    /// fails to match the @a required prototype specified at add() time, die
+    /// with LL_ERRS.
+    bool try_call(const LLSD& event) const;
+
     /// @name Iterate over defined names
     //@{
     typedef std::pair<std::string, std::string> NameDesc;
@@ -122,37 +269,44 @@ public:
 private:
     struct DispatchEntry
     {
-        DispatchEntry(const Callable& func, const std::string& desc, const LLSD& required):
-            mFunc(func),
-            mDesc(desc),
-            mRequired(required)
-        {}
-        Callable mFunc;
+        DispatchEntry(const std::string& desc);
+
         std::string mDesc;
-        LLSD mRequired;
+
+        virtual void call(const std::string& desc, const LLSD& event) const = 0;
+        virtual LLSD addMetadata(LLSD) const = 0;
     };
-    typedef std::map<std::string, DispatchEntry> DispatchMap;
+    typedef boost::ptr_map<std::string, DispatchEntry> DispatchMap;
 
 public:
     /// We want the flexibility to redefine what data we store per name,
     /// therefore our public interface doesn't expose DispatchMap iterators,
     /// or DispatchMap itself, or DispatchEntry. Instead we explicitly
     /// transform each DispatchMap item to NameDesc on dereferencing.
-    typedef boost::transform_iterator<NameDesc(*)(const DispatchMap::value_type&), DispatchMap::const_iterator> const_iterator;
+    typedef boost::transform_iterator<NameDesc(*)(DispatchMap::value_type), DispatchMap::iterator> const_iterator;
     const_iterator begin() const
     {
-        return boost::make_transform_iterator(mDispatch.begin(), makeNameDesc);
+        // Originally we used DispatchMap::const_iterator, which Just Worked
+        // when DispatchMap was a std::map. Now that it's a boost::ptr_map,
+        // using DispatchMap::const_iterator doesn't work so well: it
+        // dereferences to a pair<string, const T*>, whereas
+        // DispatchMap::value_type is just pair<string, T*>. Trying to pass a
+        // dereferenced iterator to the value_type didn't work because the
+        // compiler won't let you convert from const T* to plain T*. Changing
+        // our const_iterator definition above to be based on non-const
+        // DispatchMap::iterator works better, but of course we have to cast
+        // away the constness of mDispatch to use non-const iterator. (Sigh.)
+        return boost::make_transform_iterator(const_cast<DispatchMap&>(mDispatch).begin(),
+                                              makeNameDesc);
     }
     const_iterator end() const
     {
-        return boost::make_transform_iterator(mDispatch.end(), makeNameDesc);
+        // see begin() comments
+        return boost::make_transform_iterator(const_cast<DispatchMap&>(mDispatch).end(),
+                                              makeNameDesc);
     }
     //@}
 
-    /// Fetch the Callable for the specified name. If no such name was
-    /// registered, return an empty() Callable.
-    Callable get(const std::string& name) const;
-
     /// Get information about a specific Callable
     LLSD getMetadata(const std::string& name) const;
 
@@ -175,18 +329,184 @@ private:
         }
     }
     void addFail(const std::string& name, const std::string& classname) const;
-    /// try to dispatch, return @c true if success
-    bool attemptCall(const std::string& name, const LLSD& event) const;
 
     std::string mDesc, mKey;
     DispatchMap mDispatch;
 
-    static NameDesc makeNameDesc(const DispatchMap::value_type& item)
+    static NameDesc makeNameDesc(DispatchMap::value_type item)
     {
-        return NameDesc(item.first, item.second.mDesc);
+        return NameDesc(item.first, item.second->mDesc);
     }
+
+    struct LLSDDispatchEntry;
+    struct ParamsDispatchEntry;
+    struct ArrayParamsDispatchEntry;
+    struct MapParamsDispatchEntry;
+
+    // Step 2 of parameter analysis. Instantiating invoker<some_function_type>
+    // implicitly sets its From and To parameters to the (compile time) begin
+    // and end iterators over that function's parameter types.
+    template< typename Function
+              , class From = typename boost::mpl::begin< boost::function_types::parameter_types<Function> >::type
+              , class To   = typename boost::mpl::end< boost::function_types::parameter_types<Function> >::type
+              >
+    struct invoker;
+
+    // deliver LLSD arguments one at a time
+    typedef boost::function<LLSD()> args_source;
+    // obtain args from an args_source to build param list and call target
+    // function
+    typedef boost::function<void(const args_source&)> invoker_function;
+
+    template <typename Function>
+    invoker_function make_invoker(Function f);
+    template <typename Method, typename InstanceGetter>
+    invoker_function make_invoker(Method f, const InstanceGetter& getter);
+    void addArrayParamsDispatchEntry(const std::string& name,
+                                     const std::string& desc,
+                                     const invoker_function& invoker,
+                                     LLSD::Integer arity);
+    void addMapParamsDispatchEntry(const std::string& name,
+                                   const std::string& desc,
+                                   const invoker_function& invoker,
+                                   const LLSD& params,
+                                   const LLSD& defaults);
 };
 
+/*****************************************************************************
+*   LLEventDispatcher template implementation details
+*****************************************************************************/
+// Step 3 of parameter analysis, the recursive case.
+template<typename Function, class From, class To>
+struct LLEventDispatcher::invoker
+{
+    template<typename T>
+    struct remove_cv_ref
+        : boost::remove_cv< typename boost::remove_reference<T>::type >
+    { };
+
+    // apply() accepts an arbitrary boost::fusion sequence as args. It
+    // examines the next parameter type in the parameter-types sequence
+    // bounded by From and To, obtains the next LLSD object from the passed
+    // args_source and constructs an LLSDParam of appropriate type to try
+    // to convert the value. It then recurs with the next parameter-types
+    // iterator, passing the args sequence thus far.
+    template<typename Args>
+    static inline
+    void apply(Function func, const args_source& argsrc, Args const & args)
+    {
+        typedef typename boost::mpl::deref<From>::type arg_type;
+        typedef typename boost::mpl::next<From>::type next_iter_type;
+        typedef typename remove_cv_ref<arg_type>::type plain_arg_type;
+
+        invoker<Function, next_iter_type, To>::apply
+        ( func, argsrc, boost::fusion::push_back(args, LLSDParam<plain_arg_type>(argsrc())));
+    }
+
+    // Special treatment for instance (first) parameter of a non-static member
+    // function. Accept the instance-getter callable, calling that to produce
+    // the first args value. Since we know we're at the top of the recursion
+    // chain, we need not also require a partial args sequence from our caller.
+    template <typename InstanceGetter>
+    static inline
+    void method_apply(Function func, const args_source& argsrc, const InstanceGetter& getter)
+    {
+        typedef typename boost::mpl::next<From>::type next_iter_type;
+
+        // Instead of grabbing the first item from argsrc and making an
+        // LLSDParam of it, call getter() and pass that as the instance param.
+        invoker<Function, next_iter_type, To>::apply
+        ( func, argsrc, boost::fusion::push_back(boost::fusion::nil(), boost::ref(getter())));
+    }
+};
+
+// Step 4 of parameter analysis, the leaf case. When the general
+// invoker<Function, From, To> logic has advanced From until it matches To,
+// the compiler will pick this template specialization.
+template<typename Function, class To>
+struct LLEventDispatcher::invoker<Function,To,To>
+{
+    // the argument list is complete, now call the function
+    template<typename Args>
+    static inline
+    void apply(Function func, const args_source&, Args const & args)
+    {
+        boost::fusion::invoke(func, args);
+    }
+};
+
+template<typename Function>
+typename boost::enable_if< boost::function_types::is_nonmember_callable_builtin<Function> >::type
+LLEventDispatcher::add(const std::string& name, const std::string& desc, Function f)
+{
+    // Construct an invoker_function, a callable accepting const args_source&.
+    // Add to DispatchMap an ArrayParamsDispatchEntry that will handle the
+    // caller's LLSD::Array.
+    addArrayParamsDispatchEntry(name, desc, make_invoker(f),
+                                boost::function_types::function_arity<Function>::value);
+}
+
+template<typename Method, typename InstanceGetter>
+typename boost::enable_if< boost::function_types::is_member_function_pointer<Method> >::type
+LLEventDispatcher::add(const std::string& name, const std::string& desc, Method f,
+                       const InstanceGetter& getter)
+{
+    // Subtract 1 from the compile-time arity because the getter takes care of
+    // the first parameter. We only need (arity - 1) additional arguments.
+    addArrayParamsDispatchEntry(name, desc, make_invoker(f, getter),
+                                boost::function_types::function_arity<Method>::value - 1);
+}
+
+template<typename Function>
+typename boost::enable_if< boost::function_types::is_nonmember_callable_builtin<Function> >::type
+LLEventDispatcher::add(const std::string& name, const std::string& desc, Function f,
+                       const LLSD& params, const LLSD& defaults)
+{
+    // See comments for previous is_nonmember_callable_builtin add().
+    addMapParamsDispatchEntry(name, desc, make_invoker(f), params, defaults);
+}
+
+template<typename Method, typename InstanceGetter>
+typename boost::enable_if< boost::function_types::is_member_function_pointer<Method> >::type
+LLEventDispatcher::add(const std::string& name, const std::string& desc, Method f,
+                       const InstanceGetter& getter,
+                       const LLSD& params, const LLSD& defaults)
+{
+    addMapParamsDispatchEntry(name, desc, make_invoker(f, getter), params, defaults);
+}
+
+template <typename Function>
+LLEventDispatcher::invoker_function
+LLEventDispatcher::make_invoker(Function f)
+{
+    // Step 1 of parameter analysis, the top of the recursion. Passing a
+    // suitable f (see add()'s enable_if condition) to this method causes it
+    // to infer the function type; specifying that function type to invoker<>
+    // causes it to fill in the begin/end MPL iterators over the function's
+    // list of parameter types.
+    // While normally invoker::apply() could infer its template type from the
+    // boost::fusion::nil parameter value, here we must be explicit since
+    // we're boost::bind()ing it rather than calling it directly.
+    return boost::bind(&invoker<Function>::template apply<boost::fusion::nil>,
+                       f,
+                       _1,
+                       boost::fusion::nil());
+}
+
+template <typename Method, typename InstanceGetter>
+LLEventDispatcher::invoker_function
+LLEventDispatcher::make_invoker(Method f, const InstanceGetter& getter)
+{
+    // Use invoker::method_apply() to treat the instance (first) arg specially.
+    return boost::bind(&invoker<Method>::template method_apply<InstanceGetter>,
+                       f,
+                       _1,
+                       getter);
+}
+
+/*****************************************************************************
+*   LLDispatchListener
+*****************************************************************************/
 /**
  * Bundle an LLEventPump and a listener with an LLEventDispatcher. A class
  * that contains (or derives from) LLDispatchListener need only specify the
diff --git a/indra/llcommon/tests/lleventdispatcher_test.cpp b/indra/llcommon/tests/lleventdispatcher_test.cpp
new file mode 100644
index 0000000000..a1d7cf9ead
--- /dev/null
+++ b/indra/llcommon/tests/lleventdispatcher_test.cpp
@@ -0,0 +1,436 @@
+/**
+ * @file   lleventdispatcher_test.cpp
+ * @author Nat Goodspeed
+ * @date   2011-01-20
+ * @brief  Test for lleventdispatcher.
+ * 
+ * $LicenseInfo:firstyear=2011&license=viewerlgpl$
+ * Copyright (c) 2011, Linden Research, Inc.
+ * $/LicenseInfo$
+ */
+
+// Precompiled header
+#include "linden_common.h"
+// associated header
+#include "lleventdispatcher.h"
+// STL headers
+// std headers
+// external library headers
+// other Linden headers
+#include "../test/lltut.h"
+#include "llsd.h"
+#include "llsdutil.h"
+#include "stringize.h"
+#include "tests/wrapllerrs.h"
+
+// http://www.boost.org/doc/libs/1_45_0/libs/function_types/example/interpreter.hpp
+// downloaded 2011-01-20 by NRG and adapted with example usage
+// (C) Copyright Tobias Schwinger
+//
+// Use modification and distribution are subject to the boost Software License,
+// Version 1.0. (See http://www.boost.org/LICENSE_1_0.txt).
+
+//------------------------------------------------------------------------------
+//
+// This example implements a simple batch-style dispatcher that is capable of
+// calling functions previously registered with it. The parameter types of the
+// functions are used to control the parsing of the input.
+//
+// Implementation description
+// ==========================
+//
+// When a function is registered, an 'invoker' template is instantiated with
+// the function's type. The 'invoker' fetches a value from the 'arg_source'
+// for each parameter of the function into a tuple and finally invokes the the
+// function with these values as arguments. The invoker's entrypoint, which
+// is a function of the callable builtin that describes the function to call and
+// a reference to the 'arg_source', is partially bound to the registered
+// function and put into a map so it can be found by name during parsing.
+
+#include <map>
+#include <string>
+#include <stdexcept>
+
+#include <boost/bind.hpp>
+#include <boost/function.hpp>
+#include <boost/range.hpp>
+
+#include <boost/lambda/lambda.hpp>
+
+#include <iostream>
+
+using boost::lambda::constant;
+using boost::lambda::constant_ref;
+using boost::lambda::var;
+
+/*****************************************************************************
+*   Output control
+*****************************************************************************/
+#ifdef DEBUG_ON
+using std::cout;
+#else
+static std::ostringstream cout;
+#endif
+
+/*****************************************************************************
+*   Example data, functions, classes
+*****************************************************************************/
+// sensing globals
+static std::string gs;
+static float gf;
+static int gi;
+static LLSD gl;
+
+void clear()
+{
+    gs.clear();
+    gf = 0;
+    gi = 0;
+    gl = LLSD();
+}
+
+void abc(const std::string& message)
+{
+    cout << "abc('" << message << "')\n";
+    gs = message;
+}
+
+void def(float value, std::string desc)
+{
+    cout << "def(" << value << ", '" << desc << "')\n";
+    gf = value;
+    gs = desc;
+}
+
+void ghi(const std::string& foo, int bar)
+{
+    cout << "ghi('" << foo << "', " << bar << ")\n";
+    gs = foo;
+    gi = bar;
+}
+
+void jkl(const char* message)
+{
+    cout << "jkl('" << message << "')\n";
+    gs = message;
+}
+
+void somefunc(const LLSD& value)
+{
+    cout << "somefunc(" << value << ")\n";
+    gl = value;
+}
+
+class Dummy
+{
+public:
+    Dummy(): _id("Dummy") {}
+
+    void mno(const std::string& message)
+    {
+        cout << _id << "::mno('" << message << "')\n";
+        s = message;
+    }
+
+    void pqr(float value, std::string desc)
+    {
+        cout << _id << "::pqr(" << value << ", '" << desc << "')\n";
+        f = value;
+        s = desc;
+    }
+
+    void stu(const std::string& foo, int bar)
+    {
+        cout << _id << "::stu('" << foo << "', " << bar << ")\n";
+        s = foo;
+        i = bar;
+    }
+
+    void vwx(const char* message)
+    {
+        cout << _id << "::vwx('" << message << "')\n";
+        s = message;
+    }
+
+    static void yz1(const std::string& message)
+    {
+        cout << "Dummy::yz1('" << message << "')\n";
+        // can't access sensing members...
+        gs = message;
+    }
+
+    // sensing members
+    std::string s;
+    float f;
+    int i;
+
+private:
+    std::string _id;
+};
+
+/*****************************************************************************
+*   TUT
+*****************************************************************************/
+namespace tut
+{
+    struct lleventdispatcher_data
+    {
+        WrapLL_ERRS redirect;
+        LLEventDispatcher work;
+        Dummy dummy;
+
+        lleventdispatcher_data():
+            work("test dispatcher", "op")
+        {
+            // This object is reconstructed for every test<n> method. But
+            // clear global variables every time too.
+            ::clear();
+
+            work.add("abc", "abc", abc, LLSDArray("message"));
+            work.add("def", "def", def);
+            work.add("ghi", "ghi", ghi);
+            work.add("jkl", "jkl", jkl);
+            work.add("yz1", "yz1", &Dummy::yz1);
+            work.add("mno", "mno", &Dummy::mno, var(dummy),
+                     LLSDArray("message"), LLSDArray("default message"));
+            work.add("mnoptr", "mno", &Dummy::mno, constant(&dummy));
+            work.add("pqr", "pqr", &Dummy::pqr, var(dummy),
+                     LLSDArray("value")("desc"));
+            work.add("stu", "stu", &Dummy::stu, var(dummy),
+                     LLSDArray("foo")("bar"), LLSDArray(-1));
+            work.add("vwx", "vwx", &Dummy::vwx, var(dummy),
+                     LLSDArray("message"));
+        }
+
+        void ensure_has(const std::string& outer, const std::string& inner)
+        {
+            ensure(STRINGIZE("'" << outer << "' does not contain '" << inner << "'").c_str(),
+                   outer.find(inner) != std::string::npos);
+        }
+
+        void call_exc(const std::string& func, const LLSD& args, const std::string& exc_frag)
+        {
+            std::string threw;
+            try
+            {
+                work(func, args);
+            }
+            catch (const std::runtime_error& e)
+            {
+                cout << "*** " << e.what() << '\n';
+                threw = e.what();
+            }
+            ensure_has(threw, exc_frag);
+        }
+    };
+    typedef test_group<lleventdispatcher_data> lleventdispatcher_group;
+    typedef lleventdispatcher_group::object object;
+    lleventdispatcher_group lleventdispatchergrp("lleventdispatcher");
+
+    template<> template<>
+    void object::test<1>()
+    {
+        LLSD hello("Hello test!");
+//        cout << std::string(hello) << "\n";
+        clear();
+        jkl(LLSDParam<const char*>(hello));
+        ensure_equals(gs, hello.asString());
+    }
+
+    template<> template<>
+    void object::test<2>()
+    {
+        somefunc("abc");
+        ensure_equals(gl.asString(), "abc");
+
+        somefunc(17);
+        ensure_equals(gl.asInteger(), 17);
+
+        somefunc(3.14);
+        // 7 bits is 128, just enough to express two decimal places.
+        ensure_approximately_equals(gl.asReal(), 3.14, 7);
+
+        somefunc(LLSD().with(0, "abc").with(1, 17).with(2, 3.14));
+        ensure(gl.isArray());
+        ensure_equals(gl.size(), 4); // !!! bug in LLSD::with(Integer, const LLSD&) !!!
+        ensure_equals(gl[1].asInteger(), 17);
+
+        somefunc(LLSD().with("alpha", "abc").with("random", 17).with("pi", 3.14));
+        ensure(gl.isMap());
+        ensure_equals(gl.size(), 3);
+        ensure_equals(gl["random"].asInteger(), 17);
+
+        somefunc(LLSDArray("abc")(17)(3.14));
+        ensure(gl.isArray());
+        ensure_equals(gl.size(), 3);
+        ensure_equals(gl[0].asString(), "abc");
+
+        somefunc(LLSDMap("alpha", "abc")("random", 17)("pi", 3.14));
+        ensure(gl.isMap());
+        ensure_equals(gl.size(), 3);
+        ensure_equals(gl["alpha"].asString(), "abc");
+    }
+
+    template<> template<>
+    void object::test<3>()
+    {
+        call_exc("gofish", LLSDArray(1), "not found");
+    }
+
+    template<> template<>
+    void object::test<4>()
+    {
+        call_exc("abc", LLSD(), "missing required");
+    }
+
+    template<> template<>
+    void object::test<5>()
+    {
+        work("abc", LLSDMap("message", "something"));
+        ensure_equals(gs, "something");
+    }
+
+    template<> template<>
+    void object::test<6>()
+    {
+        work("abc", LLSDMap("message", "something")("plus", "more"));
+        ensure_equals(gs, "something");
+    }
+
+    template<> template<>
+    void object::test<7>()
+    {
+        call_exc("def", LLSDMap("value", 20)("desc", "questions"), "needs an args array");
+    }
+
+    template<> template<>
+    void object::test<8>()
+    {
+        work("def", LLSDArray(20)("questions"));
+        ensure_equals(gf, 20);
+        ensure_equals(gs, "questions");
+    }
+
+    template<> template<>
+    void object::test<9>()
+    {
+        work("def", LLSDArray(3.14)("pies"));
+        ensure_approximately_equals(gf, 3.14, 7);
+        ensure_equals(gs, "pies");
+    }
+
+    template<> template<>
+    void object::test<10>()
+    {
+        work("ghi", LLSDArray("answer")(17));
+        ensure_equals(gs, "answer");
+        ensure_equals(gi, 17);
+    }
+
+    template<> template<>
+    void object::test<11>()
+    {
+        work("ghi", LLSDArray("answer")(3.14));
+        ensure_equals(gs, "answer");
+        ensure_equals(gi, 3);
+    }
+
+    template<> template<>
+    void object::test<12>()
+    {
+        work("jkl", LLSDArray("sample message"));
+        ensure_equals(gs, "sample message");
+    }
+
+    template<> template<>
+    void object::test<13>()
+    {
+        work("yz1", LLSDArray("w00t"));
+        ensure_equals(gs, "w00t");
+    }
+
+    template<> template<>
+    void object::test<14>()
+    {
+        std::string msg("nonstatic member function");
+        work("mno", LLSDMap("message", msg));
+        ensure_equals(dummy.s, msg);
+    }
+
+    template<> template<>
+    void object::test<15>()
+    {
+        std::string msg("nonstatic member function reached by ptr");
+        work("mnoptr", LLSDArray(msg));
+        ensure_equals(dummy.s, msg);
+    }
+
+    template<> template<>
+    void object::test<16>()
+    {
+        work("mno", LLSD());
+        ensure_equals(dummy.s, "default message");
+    }
+
+    template<> template<>
+    void object::test<17>()
+    {
+        work("pqr", LLSDMap("value", 3.14)("desc", "pies"));
+        ensure_approximately_equals(dummy.f, 3.14, 7);
+        ensure_equals(dummy.s, "pies");
+    }
+
+    template<> template<>
+    void object::test<18>()
+    {
+        call_exc("pqr", LLSD(), "missing required");
+    }
+
+    template<> template<>
+    void object::test<19>()
+    {
+        call_exc("pqr", LLSDMap("value", 3.14), "missing required");
+    }
+
+    template<> template<>
+    void object::test<20>()
+    {
+        call_exc("pqr", LLSDMap("desc", "pies"), "missing required");
+    }
+
+    template<> template<>
+    void object::test<21>()
+    {
+        work("stu", LLSDMap("bar", 3.14)("foo", "pies"));
+        ensure_equals(dummy.s, "pies");
+        ensure_equals(dummy.i, 3);
+    }
+
+    template<> template<>
+    void object::test<22>()
+    {
+        call_exc("stu", LLSD(), "missing required");
+    }
+
+    template<> template<>
+    void object::test<23>()
+    {
+        call_exc("stu", LLSDMap("bar", 3.14), "missing required");
+    }
+
+    template<> template<>
+    void object::test<24>()
+    {
+        work("stu", LLSDMap("foo", "pies"));
+        ensure_equals(dummy.s, "pies");
+        ensure_equals(dummy.i, -1);
+    }
+
+    template<> template<>
+    void object::test<25>()
+    {
+        std::string msg("nonstatic method(const char*)");
+        work("vwx", LLSDMap("message", msg));
+        ensure_equals(dummy.s, msg);
+    }
+} // namespace tut
diff --git a/indra/newview/lllogininstance.cpp b/indra/newview/lllogininstance.cpp
index 33e051bfab..abcd8588dc 100644
--- a/indra/newview/lllogininstance.cpp
+++ b/indra/newview/lllogininstance.cpp
@@ -480,10 +480,12 @@ LLLoginInstance::LLLoginInstance() :
 {
 	mLoginModule->getEventPump().listen("lllogininstance", 
 		boost::bind(&LLLoginInstance::handleLoginEvent, this, _1));
-	mDispatcher.add("fail.login", boost::bind(&LLLoginInstance::handleLoginFailure, this, _1));
-	mDispatcher.add("connect",    boost::bind(&LLLoginInstance::handleLoginSuccess, this, _1));
-	mDispatcher.add("disconnect", boost::bind(&LLLoginInstance::handleDisconnect, this, _1));
-	mDispatcher.add("indeterminate", boost::bind(&LLLoginInstance::handleIndeterminate, this, _1));
+	// This internal use of LLEventDispatcher doesn't really need
+	// per-function descriptions.
+	mDispatcher.add("fail.login", "", boost::bind(&LLLoginInstance::handleLoginFailure, this, _1));
+	mDispatcher.add("connect",    "", boost::bind(&LLLoginInstance::handleLoginSuccess, this, _1));
+	mDispatcher.add("disconnect", "", boost::bind(&LLLoginInstance::handleDisconnect, this, _1));
+	mDispatcher.add("indeterminate", "", boost::bind(&LLLoginInstance::handleIndeterminate, this, _1));
 }
 
 LLLoginInstance::~LLLoginInstance()
@@ -625,11 +627,7 @@ bool LLLoginInstance::handleLoginEvent(const LLSD& event)
 
 	// Call the method registered in constructor, if any, for more specific
 	// handling
-	LLEventDispatcher::Callable method(mDispatcher.get(event["change"]));
-	if (! method.empty())
-	{
-		method(event);
-	}
+	mDispatcher.try_call(event);
 	return false;
 }