MAINT-6584: Streamline static LLImageJ2C implementation API.

Specifically, remove unused function pointer types CreateLLImageJ2CFunction,
DestroyLLImageJ2CFunction and EngineInfoLLImageJ2CFunction.

Also eliminate static fallbackDestroyLLImageJ2CImpl() and
fallbackEngineInfoLLImageJ2CImpl(), leaving only static
fallbackCreateLLImageJ2CImpl().

We do need a factory function to instantiate the appropriate LLImageJ2CImpl
subclass, so leave the fallbackCreateLLImageJ2CImpl() link seam in place.

However, given that every known LLImageJ2CImpl subclass is cheap to
instantiate, make getEngineInfo() a pure virtual method on that subclass: the
static LLImageJ2C::getEngineInfo() method can temporarily construct an
instance to query. While we're at it, make getEngineInfo() return std::string
like LLImageJ2C::getEngineInfo(). It's ridiculous that
fallbackEngineInfoLLImageJ2CImpl() implementations constructed a static
std::string and returned its c_str(), only to have LLImageJ2C::getEngineInfo()
construct ANOTHER std::string from the returned const char*.

fallbackDestroyLLImageJ2CImpl() never did anything useful: it merely deleted
the passed LLImageJ2CImpl subclass pointer as the specific subclass type. But
since LLImageJ2CImpl's destructor is virtual, LLImageJ2C's destructor could
simply delete the stored LLImageJ2CImpl*. In fact, make mImpl a
boost::scoped_ptr<LLImageJ2CImpl> so we don't even have to delete it manually.

1 files changed, 3 insertions, 9 deletions

diff --git a/indra/llkdu/llimagej2ckdu.cpp b/indra/llkdu/llimagej2ckdu.cpp
index 90b8d10ecc..0906fc894e 100644
--- a/indra/llkdu/llimagej2ckdu.cpp
+++ b/indra/llkdu/llimagej2ckdu.cpp
@@ -72,21 +72,15 @@ private:
 //
 void set_default_colour_weights(kdu_params *siz);
 
+// Factory function: see declaration in llimagej2c.cpp
 LLImageJ2CImpl* fallbackCreateLLImageJ2CImpl()
 {
 	return new LLImageJ2CKDU();
 }
 
-void fallbackDestroyLLImageJ2CImpl(LLImageJ2CImpl* impl)
+std::string LLImageJ2CKDU::getEngineInfo() const
 {
-	delete impl;
-	impl = NULL;
-}
-
-const char* fallbackEngineInfoLLImageJ2CImpl()
-{
-	static std::string version = llformat("KDU %s", KDU_CORE_VERSION);
-	return version.c_str();
+	return llformat("KDU %s", KDU_CORE_VERSION);
 }
 
 class LLKDUDecodeState