Integrate llcorehttp library into lltexturefetch design.

This is the first functional viewer pass with the HTTP work of the texture fetch
code performed by the llcorehttp library.  Not exactly a 'drop-in' replacement
but a work-alike with some changes (e.g. handler notification in consumer
thread versus responder notification in worker thread).

This also includes some temporary changes in the priority scheme to prevent
the kind of priority inversion found in VWR-28996.  Scheme used here does
provide liveness if not optimal responsiveness or order-of-operation.

The llcorehttp library at this point is far from optimally performing.
Its worker thread is making relatively poor use of cycles it gets and
it doesn't idle or sleep intelligently yet.  This early integration step
helps shake out the interfaces, implementation niceties will be covered
soon.

1 files changed, 52 insertions, 7 deletions

diff --git a/indra/llcorehttp/httpcommon.h b/indra/llcorehttp/httpcommon.h
index 9de5769d57..f81be7103e 100644
--- a/indra/llcorehttp/httpcommon.h
+++ b/indra/llcorehttp/httpcommon.h
@@ -122,23 +122,38 @@ enum HttpError
 	// Successful value compatible with the libcurl codes.
 	HE_SUCCESS = 0,
 
+	// Intended for HTTP reply codes 100-999, indicates that
+	// the reply should be considered an error by the application.
+	HE_REPLY_ERROR = 1,
+	
 	// Service is shutting down and requested operation will
 	// not be queued or performed.
-	HE_SHUTTING_DOWN = 1,
+	HE_SHUTTING_DOWN = 2,
 	
 	// Operation was canceled by request.
-	HE_OP_CANCELED = 2,
+	HE_OP_CANCELED = 3,
 	
 	// Invalid content range header received.
-	HE_INV_CONTENT_RANGE_HDR = 3
+	HE_INV_CONTENT_RANGE_HDR = 4
 	
 }; // end enum HttpError
 
 
-/// HttpStatus encapsulates errors from libcurl (easy, multi) as well as
-/// internal errors.  The encapsulation isn't expected to completely
-/// isolate the caller from libcurl but basic operational tests (success
-/// or failure) are provided.
+/// HttpStatus encapsulates errors from libcurl (easy, multi), HTTP
+/// reply status codes and internal errors as well.  The encapsulation
+/// isn't expected to completely isolate the caller from libcurl but
+/// basic operational tests (success or failure) are provided.
+///
+/// Non-HTTP status are encoded as (type, status) with type being
+/// one of:  EXT_CURL_EASY, EXT_CURL_MULTI or LLCORE and status
+/// being the success/error code from that domain.  HTTP status
+/// is encoded as (status, error_flag).  Status should be in the
+/// range [100, 999] and error_flag is either HE_SUCCESS or
+/// HE_REPLY_ERROR to indicate whether this should be treated as
+/// a successful status or an error.  The application is responsible
+/// for making that determination and a range like [200, 299] isn't
+/// automatically assumed to be definitive.
+
 struct HttpStatus
 {
 	typedef unsigned short type_enum_t;
@@ -192,12 +207,42 @@ struct HttpStatus
 		return 0 != mStatus;
 	}
 
+	/// Equality and inequality tests to bypass bool conversion
+	/// which will do the wrong thing in conditional expressions.
+	bool operator==(const HttpStatus & rhs) const
+	{
+		return mType == rhs.mType && mStatus == rhs.mStatus;
+	}
+
+	bool operator!=(const HttpStatus & rhs) const
+	{
+		return ! operator==(rhs);
+	}
+
+	/// Convert to single numeric representation.  Mainly
+	/// for logging or other informal purposes.  Also
+	/// creates an ambiguous second path to integer conversion
+	/// which tends to find programming errors such as formatting
+	/// the status to a stream (operator<<).
+	operator unsigned long() const;
+	unsigned long toULong() const
+	{
+		return operator unsigned long();
+	}
+	
 	/// Convert status to a string representation.  For
 	/// success, returns an empty string.  For failure
 	/// statuses, a string as appropriate for the source of
 	/// the error code (libcurl easy, libcurl multi, or
 	/// LLCore itself).
 	std::string toString() const;
+
+	/// Returns true if the status value represents an
+	/// HTTP response status (100 - 999).
+	bool isHttpStatus() const
+	{
+		return 	mType >= type_enum_t(100) && mType <= type_enum_t(999);
+	}
 	
 }; // end struct HttpStatus