diff options
Diffstat (limited to 'indra/llcommon/lua_function.cpp')
| -rw-r--r-- | indra/llcommon/lua_function.cpp | 572 |
1 files changed, 558 insertions, 14 deletions
diff --git a/indra/llcommon/lua_function.cpp b/indra/llcommon/lua_function.cpp index 880bc209f6..c3d336bfcb 100644 --- a/indra/llcommon/lua_function.cpp +++ b/indra/llcommon/lua_function.cpp @@ -26,6 +26,7 @@ // other Linden headers #include "fsyspath.h" #include "hexdump.h" +#include "llcoros.h" #include "lleventcoro.h" #include "llsd.h" #include "llsdutil.h" @@ -64,10 +65,26 @@ int dostring(lua_State* L, const std::string& desc, const std::string& text) if (r != LUA_OK) return r; + // Push debug.traceback() onto the stack as lua_pcall()'s error + // handler function. On error, lua_pcall() calls the specified error + // handler function with the original error message; the message + // returned by the error handler is then returned by lua_pcall(). + // Luau's debug.traceback() is called with a message to prepend to the + // returned traceback string. Almost as if they'd been designed to + // work together... + lua_getglobal(L, "debug"); + lua_getfield(L, -1, "traceback"); + // ditch "debug" + lua_remove(L, -2); + // stack: compiled chunk, debug.traceback() + lua_insert(L, -2); + // stack: debug.traceback(), compiled chunk + LuaRemover cleanup(L, -2); + // It's important to pass LUA_MULTRET as the expected number of return // values: if we pass any fixed number, we discard any returned values // beyond that number. - return lua_pcall(L, 0, LUA_MULTRET, 0); + return lua_pcall(L, 0, LUA_MULTRET, -2); } int loadstring(lua_State *L, const std::string &desc, const std::string &text) @@ -100,6 +117,34 @@ fsyspath source_path(lua_State* L) } // namespace lluau /***************************************************************************** +* lua_destroyuserdata(), lua_destroybounduserdata() (see lua_emplace<T>()) +*****************************************************************************/ +int lua_destroyuserdata(lua_State* L) +{ + // stack: lua_emplace() userdata to be destroyed + if (int tag; + lua_isuserdata(L, -1) && + (tag = lua_userdatatag(L, -1)) != 0) + { + auto dtor = lua_getuserdatadtor(L, tag); + // detach this userdata from the destructor with tag 'tag' + lua_setuserdatatag(L, -1, 0); + // now run the real destructor + dtor(L, lua_touserdata(L, -1)); + } + lua_settop(L, 0); + return 0; +} + +int lua_destroybounduserdata(lua_State *L) +{ + // called with no arguments -- push bound upvalue + lluau_checkstack(L, 1); + lua_pushvalue(L, lua_upvalueindex(1)); + return lua_destroyuserdata(L); +} + +/***************************************************************************** * Lua <=> C++ conversions *****************************************************************************/ std::string lua_tostdstring(lua_State* L, int index) @@ -467,6 +512,20 @@ namespace using LuaStateMap = std::unordered_map<lua_State*, LuaState*>; static LuaStateMap sLuaStateMap; +// replace table-at-index[name] with passed func, +// binding the original table-at-index[name] as func's upvalue +void replace_entry(lua_State* L, int index, + const std::string& name, lua_CFunction func); + +// replacement next() function that understands setdtor() proxy args +int lua_proxydrill(lua_State* L); +// replacement pairs() function that supports __iter() metamethod +int lua_metapairs(lua_State* L); +// replacement ipairs() function that supports __index() metamethod +int lua_metaipairs(lua_State* L); +// helper for lua_metaipairs() (actual generator function) +int lua_metaipair(lua_State* L); + } // anonymous namespace LuaState::LuaState(script_finished_fn cb): @@ -484,8 +543,143 @@ LuaState::LuaState(script_finished_fn cb): lua_register(mState, "print", LuaFunction::get("print_info")); // We don't want to have to prefix require(). lua_register(mState, "require", LuaFunction::get("require")); + + // Replace certain key global functions so they understand our + // LL.setdtor() proxy objects. + // (We could also do this for selected library functions as well, + // e.g. the table, string, math libraries... let's see if needed.) + replace_entry(mState, LUA_GLOBALSINDEX, "next", lua_proxydrill); + // Replacing pairs() with lua_metapairs() makes global pairs() honor + // objects with __iter() metamethods. + replace_entry(mState, LUA_GLOBALSINDEX, "pairs", lua_metapairs); + // Replacing ipairs() with lua_metaipairs() makes global ipairs() honor + // objects with __index() metamethods -- as long as the object in question + // has no array entries (int keys) of its own. (If it does, object[i] will + // retrieve table[i] instead of calling __index(table, i).) + replace_entry(mState, LUA_GLOBALSINDEX, "ipairs", lua_metaipairs); +} + +namespace +{ + +void replace_entry(lua_State* L, int index, + const std::string& name, lua_CFunction func) +{ + index = lua_absindex(L, index); + lua_checkdelta(L); + // push the function's name string twice + lua_pushlstring(L, name.data(), name.length()); + lua_pushvalue(L, -1); + // stack: name, name + // look up the existing table entry + lua_rawget(L, index); + // stack: name, original function + // bind original function as the upvalue for func() + lua_pushcclosure(L, func, (name + "()").c_str(), 1); + // stack: name, func-with-bound-original + // table[name] = func-with-bound-original + lua_rawset(L, index); +} + +int lua_metapairs(lua_State* L) +{ +// LuaLog debug(L, "lua_metapairs()"); + // pairs(obj): object is at index 1 + // How many args were we passed? + int args = lua_gettop(L); + // stack: obj, ... + if (luaL_getmetafield(L, 1, "__iter")) + { + // stack: obj, ..., getmetatable(obj).__iter + } + else + { + // Push the original pairs() function, captured as our upvalue. + lua_pushvalue(L, lua_upvalueindex(1)); + // stack: obj, ..., original pairs() + } + lua_insert(L, 1); + // stack: (__iter() or pairs()), obj, ... + // call whichever function(obj, ...) (args args, up to 3 return values) + lua_call(L, args, LUA_MULTRET); + // return as many values as the selected function returned + return lua_gettop(L); +} + +int lua_metaipairs(lua_State* L) +{ +// LuaLog debug(L, "lua_metaipairs()"); + // ipairs(obj): object is at index 1 + // How many args were we passed? + int args = lua_gettop(L); + // stack: obj, ... + if (luaL_getmetafield(L, 1, "__index")) + { + // stack: obj, ..., getmetatable(obj).__index + // discard __index and everything but obj: + // we don't want to call __index(), just check its presence + lua_settop(L, 1); + // stack: obj + lua_pushcfunction(L, lua_metaipair, "lua_metaipair"); + // stack: obj, lua_metaipair + lua_insert(L, 1); + // stack: lua_metaipair, obj + // push explicit 0 so lua_metaipair need not special-case nil + lua_pushinteger(L, 0); + // stack: lua_metaipair, obj, 0 + return 3; + } + else // no __index() metamethod + { + // Although our lua_metaipair() function demonstrably works whether or + // not our object has an __index() metamethod, the code below assumes + // that the Lua engine may have a more efficient implementation for + // built-in ipairs() than our lua_metaipair(). + // Push the original ipairs() function, captured as our upvalue. + lua_pushvalue(L, lua_upvalueindex(1)); + // stack: obj, ..., original ipairs() + // Shift the stack so the original function is first. + lua_insert(L, 1); + // stack: original ipairs(), obj, ... + // Call original ipairs() with all original args, no error checking. + // Don't truncate however many values that function returns. + lua_call(L, args, LUA_MULTRET); + // Return as many values as the original function returned. + return lua_gettop(L); + } +} + +int lua_metaipair(lua_State* L) +{ +// LuaLog debug(L, "lua_metaipair()"); + // called with (obj, previous-index) + // increment previous-index for this call + lua_Integer i = luaL_optinteger(L, 2, 0) + 1; + lua_pop(L, 1); + // stack: obj + lua_pushinteger(L, i); + // stack: obj, i + lua_pushvalue(L, -1); + // stack: obj, i, i + lua_insert(L, 1); + // stack: i, obj, i + lua_gettable(L, -2); + // stack: i, obj, obj[i] (honoring __index()) + lua_remove(L, -2); + // stack: i, obj[i] + if (! lua_isnil(L, -1)) + { + // great, obj[i] isn't nil: return (i, obj[i]) + return 2; + } + // obj[i] is nil. ipairs() is documented to stop at the first hole, + // regardless of #obj. Clear the stack, i.e. return nil. + lua_settop(L, 0); + return 0; } +} // anonymous namespace + LuaState::~LuaState() { // We're just about to destroy this lua_State mState. Did this Lua chunk @@ -502,7 +696,8 @@ LuaState::~LuaState() // That's important because we walk the atexit table backwards, to // destroy last the things we created (passed to LL.atexit()) first. int len(lua_objlen(mState, -1)); - LL_DEBUGS("Lua") << "Registry.atexit is a table with " << len << " entries" << LL_ENDL; + LL_DEBUGS("Lua") << LLCoros::getName() << ": Registry.atexit is a table with " + << len << " entries" << LL_ENDL; // Push debug.traceback() onto the stack as lua_pcall()'s error // handler function. On error, lua_pcall() calls the specified error @@ -527,15 +722,17 @@ LuaState::~LuaState() // Use lua_pcall() because errors in any one atexit() function // shouldn't cancel the rest of them. Pass debug.traceback() as // the error handler function. - LL_DEBUGS("Lua") << "Calling atexit(" << i << ")" << LL_ENDL; + LL_DEBUGS("Lua") << LLCoros::getName() + << ": calling atexit(" << i << ")" << LL_ENDL; if (lua_pcall(mState, 0, 0, -2) != LUA_OK) { auto error{ lua_tostdstring(mState, -1) }; - LL_WARNS("Lua") << "atexit(" << i << ") error: " << error << LL_ENDL; + LL_WARNS("Lua") << LLCoros::getName() + << ": atexit(" << i << ") error: " << error << LL_ENDL; // pop error message lua_pop(mState, 1); } - LL_DEBUGS("Lua") << "atexit(" << i << ") done" << LL_ENDL; + LL_DEBUGS("Lua") << LLCoros::getName() << ": atexit(" << i << ") done" << LL_ENDL; // lua_pcall() has already popped atexit[i]: // stack contains atexit, debug.traceback() } @@ -664,10 +861,10 @@ LuaListener& LuaState::obtainListener(lua_State* L) // At this point, one way or the other, the stack top should be (a Lua // userdata containing) our LuaListener. LuaListener* listener{ lua_toclass<LuaListener>(L, -1) }; - // userdata objects created by lua_emplace<T>() are bound on the atexit() - // queue, and are thus never garbage collected: they're destroyed only - // when ~LuaState() walks that queue. That's why we dare pop the userdata - // value off the stack while still depending on a pointer into its data. + // Since our LuaListener instance is stored in the Registry, it won't be + // garbage collected: it will be destroyed only when lua_close() clears + // out the Registry. That's why we dare pop the userdata value off the + // stack while still depending on a pointer into its data. lua_pop(L, 1); return *listener; } @@ -851,8 +1048,8 @@ lua_function(check_stop, "check_stop(): ensure that a Lua script responds to vie * help() *****************************************************************************/ lua_function(help, - "help(): list viewer's Lua functions\n" - "help(function): show help string for specific function") + "LL.help(): list viewer's Lua functions\n" + "LL.help(function): show help string for specific function") { auto& luapump{ LLEventPumps::instance().obtain("lua output") }; const auto& [registry, lookup]{ LuaFunction::getRState() }; @@ -911,8 +1108,8 @@ lua_function(help, *****************************************************************************/ lua_function( leaphelp, - "leaphelp(): list viewer's LEAP APIs\n" - "leaphelp(api): show help for specific api string name") + "LL.leaphelp(): list viewer's LEAP APIs\n" + "LL.leaphelp(api): show help for specific api string name") { LLSD request; int top{ lua_gettop(L) }; @@ -975,6 +1172,327 @@ lua_function( } /***************************************************************************** +* setdtor +*****************************************************************************/ +namespace { + +// proxy userdata object returned by setdtor() +struct setdtor_refs +{ + lua_State* L; + std::string desc; + // You can't directly store a Lua object in a C++ object, but you can + // create a Lua "reference" by storing the object in the Lua Registry and + // capturing its Registry index. + int objref; + int dtorref; + + setdtor_refs(lua_State* L, const std::string& desc, int objref, int dtorref): + L(L), + desc(desc), + objref(objref), + dtorref(dtorref) + {} + setdtor_refs(const setdtor_refs&) = delete; + setdtor_refs& operator=(const setdtor_refs&) = delete; + ~setdtor_refs(); + + static void push_metatable(lua_State* L); + static std::string binop(const std::string& name, const std::string& op); + static int meta__index(lua_State* L); +}; + +} // anonymous namespace + +lua_function( + setdtor, + "setdtor(desc, obj, dtorfunc) => proxy object referencing obj and dtorfunc.\n" + "When the returned proxy object is garbage-collected, or when the script\n" + "ends, call dtorfunc(obj). String desc is logged in the error message, if any.\n" + "Use the returned proxy object (or proxy._target) like obj.\n" + "obj won't be destroyed as long as the proxy exists; it's the proxy object's\n" + "lifespan that determines when dtorfunc(obj) will be called.") +{ + if (lua_gettop(L) != 3) + { + return lluau::error(L, "setdtor(desc, obj, dtor) requires exactly 3 arguments"); + } + // called with (desc, obj, dtor), returns proxy object + lua_checkdelta(L, -2); +// lluau_checkstack(L, 0); // might get up to 3 stack entries + auto desc{ lua_tostdstring(L, 1) }; + // Get Lua "references" for each of the object and the dtor function. + int objref = lua_ref(L, 2); + int dtorref = lua_ref(L, 3); + // Having captured each of our parameters, discard them. + lua_settop(L, 0); + // Push our setdtor_refs userdata. Not only do we want to push it on L's + // stack, but setdtor_refs's constructor itself requires L. + lua_emplace<setdtor_refs>(L, L, desc, objref, dtorref); + // stack: proxy (i.e. setdtor_refs userdata) + // have to set its metatable + lua_getfield(L, LUA_REGISTRYINDEX, "setdtor_meta"); + // stack: proxy, setdtor_meta (which might be nil) + if (lua_isnil(L, -1)) + { + // discard nil + lua_pop(L, 1); + // compile and push our forwarding metatable + setdtor_refs::push_metatable(L); + // stack: proxy, metatable + // duplicate metatable to save it + lua_pushvalue(L, -1); + // stack: proxy, metatable, metable + // save metatable for future calls + lua_setfield(L, LUA_REGISTRYINDEX, "setdtor_meta"); + // stack: proxy, metatable + } + // stack: proxy, metatable + lua_setmetatable(L, -2); + // stack: proxy + // Because ~setdtor_refs() necessarily uses the Lua stack, the Registry et + // al., we can't let a setdtor_refs instance be destroyed by lua_close(): + // the Lua environment will already be partially shut down. To destroy + // this new setdtor_refs instance BEFORE lua_close(), bind it with + // lua_destroybounduserdata() and register it with LL.atexit(). + // push (the entry point for) LL.atexit() + lua_pushcfunction(L, atexit_luasub::call, "LL.atexit()"); + // stack: proxy, atexit() + lua_pushvalue(L, -2); + // stack: proxy, atexit(), proxy + int tag = lua_userdatatag(L, -1); + // We don't have a lookup table to get from an int Lua userdata tag to the + // corresponding C++ typeinfo name string. We'll introduce one if we need + // it for debugging. But for this particular call, we happen to know it's + // always a setdtor_refs object. + lua_pushcclosure(L, lua_destroybounduserdata, + stringize("lua_destroybounduserdata<", tag, ">()").c_str(), + 1); + // stack: proxy, atexit(), lua_destroybounduserdata + // call atexit(): one argument, no results, let error propagate + lua_call(L, 1, 0); + // stack: proxy + return 1; +} + +namespace { + +void setdtor_refs::push_metatable(lua_State* L) +{ + lua_checkdelta(L, 1); + lluau_checkstack(L, 1); + // Ideally we want a metatable that forwards every operation on our + // setdtor_refs userdata proxy object to the original object. But the + // published C API doesn't include (e.g.) arithmetic operations on Lua + // objects, so in fact it's easier to express the desired metatable in Lua + // than in C++. We could make setdtor() depend on an external Lua module, + // but it seems less fragile to embed the Lua source code right here. + static const std::string setdtor_meta = stringize(R"-( + -- This metatable literal doesn't define __index() because that's + -- implemented in C++. We cannot, in Lua, peek into the setdtor_refs + -- userdata object to obtain objref, nor can we fetch Registry[objref]. + -- So our C++ __index() metamethod recognizes access to '_target' as a + -- reference to Registry[objref]. + -- The rest are defined per https://www.lua.org/manual/5.1/manual.html#2.8. + -- Luau supports destructors instead of __gc metamethod -- we rely on that! + -- We don't set __mode because our proxy is not a table. Real references + -- are stored in the wrapped table, so ITS __mode is what counts. + -- Initial definition of meta omits binary metamethods so they can bind the + -- metatable itself, as explained for binop() below. + local meta = { + __unm = function(arg) + return -arg._target + end, + __len = function(arg) + return #arg._target + end, + -- Comparison metamethods __eq(), __lt() and __le() are only called + -- when both operands have the same metamethod. For our purposes, that + -- means both operands are setdtor_refs userdata objects. + __eq = function(lhs, rhs) + return (lhs._target == rhs._target) + end, + __lt = function(lhs, rhs) + return (lhs._target < rhs._target) + end, + __le = function(lhs, rhs) + return (lhs._target <= rhs._target) + end, + __newindex = function(t, key, value) + assert(key ~= '_target', + "Don't try to replace a setdtor() proxy's _target") + t._target[key] = value + end, + __call = function(func, ...) + return func._target(...) + end, + __tostring = function(arg) + -- don't fret about arg._target's __tostring metamethod, + -- if any, because built-in tostring() deals with that + return tostring(arg._target) + end, + __iter = function(arg) + local iter = (getmetatable(arg._target) or {}).__iter + if iter then + return iter(arg._target) + else + return next, arg._target + end + end + } +)-", + binop("add", "+"), + binop("sub", "-"), + binop("mul", "*"), + binop("div", "/"), + binop("idiv", "//"), + binop("mod", "%"), + binop("pow", "^"), + binop("concat", ".."), +R"-( + return meta +)-"); + // only needed for debugging binop() +// LL_DEBUGS("Lua") << setdtor_meta << LL_ENDL; + + if (lluau::dostring(L, LL_PRETTY_FUNCTION, setdtor_meta) != LUA_OK) + { + // stack: error message string + lua_error(L); + } + llassert(lua_gettop(L) > 0); + llassert(lua_type(L, -1) == LUA_TTABLE); + // stack: Lua metatable compiled from setdtor_meta source + // Inject our C++ __index metamethod. + lua_rawsetfield(L, -1, "__index"sv, &setdtor_refs::meta__index); +} + +// In the definition of setdtor_meta above, binary arithmethic and +// concatenation metamethods are a little funny in that we don't know a +// priori which operand is the userdata with our metatable: the metamethod +// can be invoked either way. So every such metamethod must check, which +// leads to lots of redundancy. Hence this helper function. Call it a Lua +// macro. +std::string setdtor_refs::binop(const std::string& name, const std::string& op) +{ + return stringize( + " meta.__", name, " = function(lhs, rhs)\n" + " if getmetatable(lhs) == meta then\n" + " return lhs._target ", op, " rhs\n" + " else\n" + " return lhs ", op, " rhs._target\n" + " end\n" + " end\n"); +} + +// setdtor_refs __index() metamethod +int setdtor_refs::meta__index(lua_State* L) +{ + // called with (setdtor_refs userdata, key), returns retrieved object + lua_checkdelta(L, -1); + lluau_checkstack(L, 2); + // stack: proxy, key + // get ptr to the C++ struct data + auto ptr = lua_toclass<setdtor_refs>(L, -2); + // meta__index() should NEVER be called with anything but setdtor_refs! + llassert(ptr); + // push the wrapped object + lua_getref(L, ptr->objref); + // stack: proxy, key, _target + // replace userdata with _target + lua_replace(L, -3); + // stack: _target, key + // Duplicate key because lua_tostring() converts number to string: + // if the key is (e.g.) 1, don't try to retrieve _target["1"]! + lua_pushvalue(L, -1); + // stack: _target, key, key + // recognize the special _target field + if (lua_tostdstring(L, -1) == "_target") + { + // okay, ditch both copies of "_target" string key + lua_pop(L, 2); + // stack: _target + } + else // any key but _target + { + // ditch stringized key + lua_pop(L, 1); + // stack: _target, key + // replace key with _target[key], invoking metamethod if any + lua_gettable(L, -2); + // stack: _target, _target[key] + // discard _target + lua_remove(L, -2); + // stack: _target[key] + } + return 1; +} + +// replacement for global next(): +// its lua_upvalueindex(1) is the original function it's replacing +int lua_proxydrill(lua_State* L) +{ + // Accept however many arguments the original function normally accepts. + // If our first arg is a userdata, check if it's a setdtor_refs proxy. + // Drill through as many levels of proxy wrapper as needed. + while (const setdtor_refs* ptr = lua_toclass<setdtor_refs>(L, 1)) + { + // push original object + lua_getref(L, ptr->objref); + // replace first argument with that + lua_replace(L, 1); + } + // We've reached a first argument that's not a setdtor() proxy. + // How many arguments were we passed, anyway? + int args = lua_gettop(L); + // Push the original function, captured as our upvalue. + lua_pushvalue(L, lua_upvalueindex(1)); + // Shift the stack so the original function is first. + lua_insert(L, 1); + // Call the original function with all original args, no error checking. + // Don't truncate however many values that function returns. + lua_call(L, args, LUA_MULTRET); + // Return as many values as the original function returned. + return lua_gettop(L); +} + +// When Lua destroys a setdtor_refs userdata object, either from garbage +// collection or from LL.atexit(lua_destroybounduserdata), it's time to keep +// its promise to call the specified Lua destructor function with the +// specified Lua object. Of course we must also delete the captured +// "references" to both objects. +setdtor_refs::~setdtor_refs() +{ + lua_checkdelta(L); + lluau_checkstack(L, 2); + // push Registry[dtorref] + lua_getref(L, dtorref); + // push Registry[objref] + lua_getref(L, objref); + // free Registry[dtorref] + lua_unref(L, dtorref); + // free Registry[objref] + lua_unref(L, objref); + // call dtor(obj): one arg, no result, no error function + int rc = lua_pcall(L, 1, 0, 0); + if (rc != LUA_OK) + { + // TODO: we don't really want to propagate the error here. + // If this setdtor_refs instance is being destroyed by + // LL.atexit(), we want to continue cleanup. If it's being + // garbage-collected, the call is completely unpredictable from + // the consuming script's point of view. But what to do about this + // error?? For now, just log it. + LL_WARNS("Lua") << LLCoros::getName() + << ": setdtor(" << std::quoted(desc) << ") error: " + << lua_tostring(L, -1) << LL_ENDL; + lua_pop(L, 1); + } +} + +} // anonymous namespace + +/***************************************************************************** * lua_what *****************************************************************************/ std::ostream& operator<<(std::ostream& out, const lua_what& self) @@ -1024,6 +1542,31 @@ std::ostream& operator<<(std::ostream& out, const lua_what& self) out << lua_touserdata(self.L, self.index); break; + case LUA_TFUNCTION: + { + // Try for the function's name, at the cost of a few more stack + // entries. + lua_checkdelta(self.L); + lluau_checkstack(self.L, 3); + lua_getglobal(self.L, "debug"); + // stack: ..., debug + lua_getfield(self.L, -1, "info"); + // stack: ..., debug, debug.info + lua_remove(self.L, -2); + // stack: ..., debug.info + lua_pushvalue(self.L, self.index); + // stack: ..., debug.info, this function + lua_pushstring(self.L, "n"); + // stack: ..., debug.info, this function, "n" + // 2 arguments, 1 return value (or error message), no error handler + lua_pcall(self.L, 2, 1, 0); + // stack: ..., function name (or error) from debug.info() + out << "function " << lua_tostdstring(self.L, -1); + lua_pop(self.L, 1); + // stack: ... + break; + } + default: // anything else, don't bother trying to report value, just type out << lua_typename(self.L, lua_type(self.L, self.index)); @@ -1066,7 +1609,8 @@ LuaStackDelta::~LuaStackDelta() // instance to keep its contract wrt the Lua data stack. if (std::uncaught_exceptions() == 0 && mDepth + mDelta != depth) { - LL_ERRS("Lua") << mWhere << ": Lua stack went from " << mDepth << " to " << depth; + LL_ERRS("Lua") << LLCoros::getName() << ": " << mWhere + << ": Lua stack went from " << mDepth << " to " << depth; if (mDelta) { LL_CONT << ", rather than expected " << (mDepth + mDelta) << " (" << mDelta << ")"; |