The observed crash was due to sharing a stateful global resource (the global
LLMessageSystem instance) between different tasks. Specifically, a coroutine
sets its mMessageReader one way, expecting that value to persist until it's
done with message parsing, but another coroutine sneaks in at a suspension
point and sets it differently.
Introduce LockMessageReader and LockMessageChecker classes, which must be
instantiated by a consumer of the resource. The constructor of each locks a
coroutine-aware mutex, so that for the lifetime of the lock object no other
coroutine can instantiate another.
Refactor the code so that LLMessageSystem::mMessageReader can only be modified
by LockMessageReader, not by direct assignment. mMessageReader is now an
instance of LLMessageReaderPointer, which supports dereferencing and
comparison but not assignment. Only LockMessageReader can change its value.
LockMessageReader addresses the use case in which the specific mMessageReader
value need only persist for the duration of a single method call. Add an
instance in LLMessageHandlerBridge::post().
LockMessageChecker is a subclass of LockMessageReader: both lock the same
mutex. LockMessageChecker addresses the use case in which the specific
mMessageReader value must persist across multiple method calls. Modify the
methods in question to require a LockMessageChecker instance. Provide
LockMessageChecker forwarding methods to facilitate calling the underlying
LLMessageSystem methods via the LockMessageChecker instance.
Add LockMessageChecker instances to LLAppViewer::idleNetwork(), a couple cases
in idle_startup() and LLMessageSystem::establishBidirectionalTrust().
The problem was that class-static LLUrlEntryParcel::sRegionHost was being
initialized by copying class-static LLHost::invalid. Naturally, these two
statics are initialized in different source files. Since C++ makes no promises
about the relative order in which objects in different object files are
initialized, it seems we hit a case in which we were trying to initialize
sRegionHost by copying a completely uninitialized LLHost::invalid.
In general we might attempt to address such cross-translation-unit issues by
introducing an LLSingleton. But in this particular case, the punch line is
that LLHost::invalid is explicitly constructed identically to a
default-constructed LLHost! In other words, LLHost::invalid provides nothing
we couldn't get from LLHost(). All it gives us is an opportunity for glitches
such as the above.
Remove LLHost::invalid and all references, replacing with LLHost().
continued conversion to units system
made units perform type promotion correctly and preserve type in arithmetic
e.g. can now do LLVector3 in units
added typedefs for remaining common unit types, including implicits
consolidated most indra-specific constants in llcommon under indra_constants.h
fixed issues with operations on mixed unit types (implicit and explicit)
made LL_INFOS() style macros variadic in order to subsume other logging methods
such as ll_infos
added optional tag output to error recorders
* Additional error checking in http handlers.
* Uniform log spam for http errors.
* Switch to using constants for http heads and status codes.
* Fixed bugs in incorrectly checking if parsing LLSD xml resulted in an error.
* Reduced spam regarding LLSD parsing errors in the default completedRaw http handler. It should not longer be necessary to short-circuit completedRaw to avoid spam.
* Ported over a few bug fixes from the server code.
* Switch mode http status codes to use S32 instead of U32.
* Ported LLSD::asStringRef from server code; avoids copying strings all over the place.
* Ported server change to LLSD::asBinary; this always returns a reference now instead of copying the entire binary blob.
* Ported server pretty notation format (and pretty binary format) to llsd serialization.
* The new LLCurl::Responder API no longer has two error handlers to choose from. Overriding the following methods have been deprecated:
** error - use httpFailure
** errorWithContent - use httpFailure
** result - use httpSuccess
** completed - use httpCompleted
** completedHeader - no longer necessary; call getResponseHeaders() from a completion method to obtain these headers.
* In order to 'catch' a completed http request, override one of these methods:
** httpSuccess - Called for any 2xx status code.
** httpFailure - Called for any non-2xx status code.
** httpComplete - Called for all status codes. Default implementation is to call either httpSuccess or httpFailure.
* It is recommended to keep these methods protected/private in order to avoid triggering of these methods without using a 'push' method (see below).
* Uniform error handling should followed whenever possible by calling a variant of this during httpFailure:
** llwarns << dumpResponse() << llendl;
* Be sure to include LOG_CLASS(your_class_name) in your class in order for the log entry to give more context.
* In order to 'push' a result into the responder, you should no longer call error, errorWithContent, result, or completed.
* Nor should you directly call httpSuccess/Failure/Completed (unless passing a message up to a parent class).
* Instead, you can set the internal content of a responder and trigger a corresponding method using the following methods:
** successResult - Sets results and calls httpSuccess
** failureResult - Sets results and calls httpFailure
** completedResult - Sets results and calls httpCompleted
* To obtain information about a the response from a reponder method, use the following getters:
** getStatus - HTTP status code
** getReason - Reason string
** getContent - Content (Parsed body LLSD)
** getResponseHeaders - Response Headers (LLSD map)
** getHTTPMethod - HTTP method of the request
** getURL - URL of the request
* It is still possible to override completeRaw if you want to manipulate data directly out of LLPumpIO.
* See indra/llmessage/llcurl.h for more information.
Nicky Dasmijn