IECoreImage : Adapt to OIIO 3 ImageCache changes

There are two changes that affect us :

- `ImageCache::create()` returns a `shared_ptr`.
- `ImageCache::imagespec()` completely ignores the `miplevel` parameter, and we have to use `get_cache_dimensions()` instead.

Author: johnhaddon

src/IECoreGL/TextureLoader.cpp

@@ -56,13 +56,17 @@
 
 using namespace IECoreGL;
 
+#if OIIO_VERSION < 30000
+
 namespace{
 	void destroyImageCache( OIIO::ImageCache *cache )
 	{
 		OIIO::ImageCache::destroy( cache, /* teardown */ true );
 	}
 }
 
+#endif
+
 TextureLoader::TextureLoader( const IECore::SearchPath &searchPaths )
 	:	m_searchPaths( searchPaths )
 {
@@ -92,7 +96,12 @@ TexturePtr TextureLoader::load( const std::string &name, int maximumResolution )
 	// doesn't have mipmaps on disk ... but I'm keeping this consistent for now.
 	// To set automip, we need to create an ImageCache - currently I just destroy it when this function exits:
 	// we cache the GL texture ourselves, so dropping the OIIO cache should be OK.
+#if OIIO_VERSION >= 30000
+	std::shared_ptr<OIIO::ImageCache> imageCache = OIIO::ImageCache::create( /* shared */ false );
+#else
 	std::unique_ptr<OIIO::ImageCache, decltype(&destroyImageCache) > imageCache( OIIO::ImageCache::create( /* shared */ false ), &destroyImageCache );
+#endif
+
 	imageCache->attribute( "automip", 1 );
 
 	OIIO::ImageSpec mipSpec;
@@ -116,7 +125,14 @@ TexturePtr TextureLoader::load( const std::string &name, int maximumResolution )
 		}
 	}
 
-	OIIO::ImageBuf imageBuf( oiioPath, 0, miplevel, imageCache.get() );
+	OIIO::ImageBuf imageBuf(
+		oiioPath, 0, miplevel,
+#if OIIO_VERSION >= 30000
+		imageCache
+#else
+		imageCache.get()
+#endif
+	);
 	if( imageBuf.spec().full_x != 0 || imageBuf.spec().full_y != 0 )
 	{
 		IECore::msg( IECore::Msg::Error, "IECoreGL::TextureLoader::load", boost::format( "Texture display window must start at origin for \"%s\"." ) % path.string() );

src/IECoreImage/ImageReader.cpp

@@ -118,7 +118,7 @@ class ImageReader::Implementation
 
 	public :
 
-		Implementation( const ImageReader *reader ) : m_reader( reader ), m_cache( nullptr, &destroyImageCache )
+		Implementation( const ImageReader *reader ) : m_reader( reader )
 		{
 		}
 
@@ -251,23 +251,33 @@ class ImageReader::Implementation
 		Imath::Box2i dataWindow()
 		{
 			open( /* throwOnFailure */ true );
-			const ImageSpec *spec = m_cache->imagespec( m_inputFileName, /* subimage = */ 0, miplevel() );
+
+			ImageSpec spec;
+#if OIIO_VERSION >= 30000
+				m_cache->get_cache_dimensions( m_inputFileName, spec, /* subimage = */ 0, miplevel() );
+#else
+				spec = *m_cache->imagespec( m_inputFileName, /* subimage = */ 0, miplevel() );
+#endif
 
 			return Imath::Box2i(
-				Imath::V2i( spec->x, spec->y ),
-				Imath::V2i( spec->width + spec->x - 1, spec->height + spec->y - 1 )
+				Imath::V2i( spec.x, spec.y ),
+				Imath::V2i( spec.width + spec.x - 1, spec.height + spec.y - 1 )
 			);
 		}
 
 		Imath::Box2i displayWindow()
 		{
 			open( /* throwOnFailure */ true );
 
-			const ImageSpec *spec = m_cache->imagespec( m_inputFileName, /* subimage = */ 0, miplevel() );
-
+			ImageSpec spec;
+#if OIIO_VERSION >= 30000
+			m_cache->get_cache_dimensions( m_inputFileName, spec, /* subimage = */ 0, miplevel() );
+#else
+			spec = *m_cache->imagespec( m_inputFileName, /* subimage = */ 0, miplevel() );
+#endif
 			return Imath::Box2i(
-				Imath::V2i( spec->full_x, spec->full_y ),
-				Imath::V2i( spec->full_x + spec->full_width - 1, spec->full_y + spec->full_height - 1 )
+				Imath::V2i( spec.full_x, spec.full_y ),
+				Imath::V2i( spec.full_x + spec.full_width - 1, spec.full_y + spec.full_height - 1 )
 			);
 		}
 
@@ -441,8 +451,11 @@ class ImageReader::Implementation
 			}
 
 			m_inputFileName = "";
-			m_cache.reset( ImageCache::create( /* shared */ false ) );
-
+#if OIIO_VERSION >= 30000
+			m_cache = ImageCache::create( /* shared */ false );
+#else
+			m_cache.reset( ImageCache::create( /* shared */ false ), destroyImageCache );
+#endif
 			// Autompip ensures that if a miplevel is requested that the file
 			// doesn't contain, OIIO creates the respective level on the fly.
 			m_cache->attribute( "automip", 1 );
@@ -502,13 +515,15 @@ class ImageReader::Implementation
 			return p->getNumericValue();
 		}
 
+#if OIIO_VERSION < 30000
 		static void destroyImageCache( ImageCache *cache )
 		{
 			ImageCache::destroy( cache, /* teardown */ true );
 		}
+#endif
 
 		const ImageReader *m_reader;
-		std::unique_ptr<ImageCache, decltype(&destroyImageCache) > m_cache;
+		std::shared_ptr<ImageCache> m_cache;
 		ustring m_inputFileName;
 		std::string m_currentColorSpace;
 		std::string m_linearColorSpace;