Support cmake config and shared library for libdeflate

When not using the internal deflate, the only option was pkgconfig which
is not well supported on Windows. This adds support for using the
libdeflate cmake config files when available.

This change also affects the generated OpenEXR cmake config files. For
a static OpenEXR library, INTERFACE_LINK_LIBRARIES now appropriately
includes libdeflate along with the existing dependencies like Imath.

It also turns the internal libdeflate into a target for consistency.

Resolves #1588

cmake/LibraryDefine.cmake

@@ -27,9 +27,6 @@ function(OPENEXR_DEFINE_LIBRARY libname)
                           PRIVATE cxx_std_${OPENEXR_CXX_STANDARD}
                           INTERFACE cxx_std_11 )
 
-  # we are embedding libdeflate
-  target_include_directories(${objlib} PRIVATE ${EXR_DEFLATE_INCLUDE_DIR})
-
   if(OPENEXR_CURLIB_PRIV_EXPORT AND BUILD_SHARED_LIBS)
     target_compile_definitions(${objlib} PRIVATE ${OPENEXR_CURLIB_PRIV_EXPORT})
     if(WIN32)

cmake/OpenEXRSetup.cmake

@@ -160,15 +160,45 @@ set(OPENEXR_DEFLATE_TAG "v1.18" CACHE STRING "Tag to use for libdeflate source r
 if(NOT OPENEXR_FORCE_INTERNAL_DEFLATE)
   #TODO: ^^ Release should not clone from main, this is a place holder
   set(CMAKE_IGNORE_PATH "${CMAKE_CURRENT_BINARY_DIR}/_deps/deflate-src/config;${CMAKE_CURRENT_BINARY_DIR}/_deps/deflate-build/config")
-  include(FindPkgConfig)
-  pkg_check_modules(deflate IMPORTED_TARGET GLOBAL libdeflate)
-  set(CMAKE_IGNORE_PATH)
-  if (deflate_FOUND)
-    message(STATUS "Using libdeflate from ${deflate_LINK_LIBRARIES}")
+  # First try cmake config
+  find_package(libdeflate CONFIG)
+  if(libdeflate_FOUND)
+    if(TARGET libdeflate::libdeflate_shared)
+      set(EXR_DEFLATE_TARGET libdeflate::libdeflate_shared)
+    else()
+      set(EXR_DEFLATE_TARGET libdeflate::libdeflate_static)
+    endif()
+    set(EXR_DEFLATE_SOURCES)
+    set(EXR_DEFLATE_LDFLAGS)
+    # Set EXR_DEFATE_LDFLAGS for OpenEXR.pc.in for static build
+    if(NOT BUILD_SHARED_LIBS)
+      get_target_property(deflate_LIBRARIES ${EXR_DEFLATE_TARGET} LOCATION)
+      set(EXR_DEFLATE_LDFLAGS "-l${deflate_LIBRARIES}")
+    endif()
+    message(STATUS "Using libdeflate from ${libdeflate_DIR}")
+  else()
+    # If not found, try pkgconfig
+    find_package(PkgConfig)
+    if(PKG_CONFIG_FOUND)
+      include(FindPkgConfig)
+      pkg_check_modules(deflate IMPORTED_TARGET GLOBAL libdeflate)
+      if(deflate_FOUND)
+        set(EXR_DEFLATE_TARGET PkgConfig::deflate)
+        set(EXR_DEFLATE_SOURCES)
+        set(EXR_DEFLATE_LDFLAGS)
+        # Set EXR_DEFATE_LDFLAGS for OpenEXR.pc.in for static build
+        if(NOT BUILD_SHARED_LIBS)
+          set(EXR_DEFLATE_LDFLAGS "-l${deflate_LIBRARIES}")
+        endif()
+        message(STATUS "Using libdeflate from ${deflate_LINK_LIBRARIES}")
+      endif()
+    endif()
   endif()
+  set(CMAKE_IGNORE_PATH)
 endif()
 
-if(NOT TARGET PkgConfig::deflate AND NOT deflate_FOUND)
+if(NOT EXR_DEFLATE_TARGET)
+  # Using internal deflate.
   if(OPENEXR_FORCE_INTERNAL_DEFLATE)
     message(STATUS "libdeflate forced internal, installing from ${OPENEXR_DEFLATE_REPO} (${OPENEXR_DEFLATE_TAG})")
   else()
@@ -211,18 +241,10 @@ if(NOT TARGET PkgConfig::deflate AND NOT deflate_FOUND)
 
   # cmake makes fetch content name lowercase for the properties (to deflate)
   list(TRANSFORM EXR_DEFLATE_SOURCES PREPEND ${deflate_SOURCE_DIR}/)
-  set(EXR_DEFLATE_INCLUDE_DIR ${deflate_SOURCE_DIR})
-  set(EXR_DEFLATE_LIB)
-else()
-  set(EXR_DEFLATE_INCLUDE_DIR)
-  set(EXR_DEFLATE_LIB ${deflate_LIBRARIES})
-  # set EXR_DEFATE_LDFLAGS for OpenEXR.pc.in for static build
-  if (BUILD_SHARED_LIBS)
-    set(EXR_DEFLATE_LDFLAGS "")
-  else()
-    set(EXR_DEFLATE_LDFLAGS "-l${deflate_LIBRARIES}")
-  endif()
-  set(EXR_DEFLATE_SOURCES)
+
+  add_library(libdeflate_internal_static STATIC IMPORTED)
+  set_target_properties(libdeflate_internal_static PROPERTIES INTERFACE_INCLUDE_DIRECTORIES "${deflate_SOURCE_DIR}")
+  set(EXR_DEFLATE_TARGET libdeflate_internal_static)
 endif()
 
 #######################################

src/lib/OpenEXRCore/CMakeLists.txt

@@ -104,10 +104,10 @@ openexr_define_library(OpenEXRCore
     Imath::Imath
   )
 
-if (DEFINED EXR_DEFLATE_LIB)
+if (DEFINED EXR_DEFLATE_TARGET)
   if (BUILD_SHARED_LIBS)
-    target_link_libraries(OpenEXRCore PRIVATE ${EXR_DEFLATE_LIB})
+    target_link_libraries(OpenEXRCore PRIVATE ${EXR_DEFLATE_TARGET})
   else()
-    target_link_libraries(OpenEXRCore PUBLIC ${EXR_DEFLATE_LIB})
+    target_link_libraries(OpenEXRCore PUBLIC ${EXR_DEFLATE_TARGET})
   endif()
 endif()