Add option to compile c++ libraries with an embedded core library (#2216)

* Add option to compile c++ libraries with an embedded core library

Can configure with cmake -DOPENEXR_FORCE_EMBEDDED_CORE=ON

This will force symbols to be hidden in the Core library such that when
linked into the c++ shared library or other binary, they will be hidden
(as if there is no core library). This should not be the default config
but is supported for creating custom versions of exr.

Signed-off-by: Kimball Thurston <kdt3rd@gmail.com>

* Fix bazel build

Signed-off-by: Kimball Thurston <kdt3rd@gmail.com>

---------

Signed-off-by: Kimball Thurston <kdt3rd@gmail.com>

Author: kdt3rd

BUILD.bazel

@@ -62,6 +62,7 @@ expand_template(
         "@OPENEXR_VERSION_MINOR@": "4",
         "@OPENEXR_VERSION_PATCH@": "0",
         "#cmakedefine OPENEXR_ENABLE_API_VISIBILITY": "#define OPENEXR_ENABLE_API_VISIBILITY",
+        "#cmakedefine OPENEXR_CORE_FUNCTIONS_EMBEDDED": "/* #undef OPENEXR_CORE_FUNCTIONS_EMBEDDED */",
         "#cmakedefine OPENEXR_HAVE_LARGE_STACK 1": "/* #undef OPENEXR_HAVE_LARGE_STACK */",
     },
     template = "cmake/OpenEXRConfig.h.in",

cmake/CMakeLists.txt

@@ -63,6 +63,11 @@ if (OPENEXR_USE_DEFAULT_VISIBILITY)
 else()
   set(OPENEXR_ENABLE_API_VISIBILITY ON)
 endif()
+if (OPENEXR_FORCE_EMBEDDED_CORE)
+  set(OPENEXR_CORE_FUNCTIONS_EMBEDDED ON)
+else()
+  set(OPENEXR_CORE_FUNCTIONS_EMBEDDED OFF)
+endif()
 
 if (UNIX AND NOT APPLE AND NOT BEOS)
   find_library(OPENEXR_EXTRA_MATH_LIB m)

cmake/LibraryDefine.cmake

@@ -4,7 +4,7 @@
 # NB: This function has a number of Imath-specific names/variables
 # in it, so be careful copying...
 function(OPENEXR_DEFINE_LIBRARY libname)
-  set(options)
+  set(options EMBEDDED)
   set(oneValueArgs PRIV_EXPORT CURDIR CURBINDIR)
   set(multiValueArgs SOURCES HEADERS DEPENDENCIES PRIVATE_DEPS)
   cmake_parse_arguments(OPENEXR_CURLIB "${options}" "${oneValueArgs}" "${multiValueArgs}" ${ARGN})
@@ -13,7 +13,12 @@ function(OPENEXR_DEFINE_LIBRARY libname)
     set(_openexr_extra_flags "$<$<COMPILE_LANGUAGE:CXX>:/EHsc>" "$<$<COMPILE_LANGUAGE:CXX>:/MP>")
   endif()
   set(objlib ${libname})
-  add_library(${objlib}
+  if(OPENEXR_CURLIB_EMBEDDED)
+    set(libopts STATIC)
+  else()
+    set(libopts)
+  endif()
+  add_library(${objlib} ${libopts}
     ${OPENEXR_CURLIB_HEADERS}
     ${OPENEXR_CURLIB_SOURCES})
 
@@ -24,7 +29,9 @@ function(OPENEXR_DEFINE_LIBRARY libname)
                           PRIVATE cxx_std_${OPENEXR_CXX_STANDARD}
                           INTERFACE cxx_std_17 )
 
-  if(OPENEXR_CURLIB_PRIV_EXPORT AND BUILD_SHARED_LIBS)
+  if(OPENEXR_CURLIB_EMBEDDED)
+    set(libopts)
+  elseif(OPENEXR_CURLIB_PRIV_EXPORT AND BUILD_SHARED_LIBS)
     target_compile_definitions(${objlib} PRIVATE ${OPENEXR_CURLIB_PRIV_EXPORT})
     if(WIN32)
       target_compile_definitions(${objlib} PUBLIC OPENEXR_DLL)
@@ -46,7 +53,7 @@ function(OPENEXR_DEFINE_LIBRARY libname)
     CXX_EXTENSIONS OFF
     POSITION_INDEPENDENT_CODE ON
   )
-  if (NOT OPENEXR_USE_DEFAULT_VISIBILITY)
+  if (OPENEXR_CURLIB_EMBEDDED OR NOT OPENEXR_USE_DEFAULT_VISIBILITY)
     set_target_properties(${objlib} PROPERTIES
       C_VISIBILITY_PRESET hidden
       CXX_VISIBILITY_PRESET hidden
@@ -60,7 +67,7 @@ function(OPENEXR_DEFINE_LIBRARY libname)
   endif()
   set_property(TARGET ${objlib} PROPERTY PUBLIC_HEADER ${OPENEXR_CURLIB_HEADERS})
 
-  if(BUILD_SHARED_LIBS)
+  if(BUILD_SHARED_LIBS AND NOT OPENEXR_CURLIB_EMBEDDED)
     set_target_properties(${libname} PROPERTIES
       SOVERSION ${OPENEXR_LIB_SOVERSION}
       VERSION ${OPENEXR_LIB_VERSION}
@@ -70,7 +77,6 @@ function(OPENEXR_DEFINE_LIBRARY libname)
       OUTPUT_NAME "${libname}${OPENEXR_LIB_SUFFIX}"
       RUNTIME_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/bin"
   )
-  add_library(${PROJECT_NAME}::${libname} ALIAS ${libname})
 
   if(OPENEXR_INSTALL)
     install(TARGETS ${libname}
@@ -83,7 +89,9 @@ function(OPENEXR_DEFINE_LIBRARY libname)
         DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/${OPENEXR_OUTPUT_SUBDIR}
     )
   endif()
-  if(BUILD_SHARED_LIBS AND (NOT "${OPENEXR_LIB_SUFFIX}" STREQUAL "") AND NOT WIN32)
+  if(OPENEXR_CURLIB_EMBEDDED)
+    set(libopts)
+  elseif(BUILD_SHARED_LIBS AND (NOT "${OPENEXR_LIB_SUFFIX}" STREQUAL "") AND NOT WIN32)
     string(TOUPPER "${CMAKE_BUILD_TYPE}" uppercase_CMAKE_BUILD_TYPE)
     set(verlibname ${CMAKE_SHARED_LIBRARY_PREFIX}${libname}${OPENEXR_LIB_SUFFIX}${CMAKE_${uppercase_CMAKE_BUILD_TYPE}_POSTFIX}${CMAKE_SHARED_LIBRARY_SUFFIX})
     set(baselibname ${CMAKE_SHARED_LIBRARY_PREFIX}${libname}${CMAKE_${uppercase_CMAKE_BUILD_TYPE}_POSTFIX}${CMAKE_SHARED_LIBRARY_SUFFIX})
@@ -93,4 +101,6 @@ function(OPENEXR_DEFINE_LIBRARY libname)
     set(verlibname)
     set(baselibname)
   endif()
+
+  add_library(${PROJECT_NAME}::${libname} ALIAS ${libname})
 endfunction()

cmake/OpenEXRConfig.h.in

@@ -93,6 +93,8 @@
 // tagged
 #cmakedefine OPENEXR_ENABLE_API_VISIBILITY
 
+#cmakedefine OPENEXR_CORE_FUNCTIONS_EMBEDDED
+
 /// \defgroup ExportMacros Macros to manage symbol visibility
 ///
 /// See website/SymbolVisibility.rst for more discussion about the

src/lib/OpenEXRCore/CMakeLists.txt

@@ -1,7 +1,13 @@
 # SPDX-License-Identifier: BSD-3-Clause
 # Copyright Contributors to the OpenEXR Project.
 
+if (OPENEXR_FORCE_EMBEDDED_CORE)
+  message(STATUS "Building Core library as an embedded library")
+  set(coreopts EMBEDDED)
+endif()
+
 openexr_define_library(OpenEXRCore
+  ${coreopts}
   PRIV_EXPORT OPENEXRCORE_EXPORTS
   CURDIR ${CMAKE_CURRENT_SOURCE_DIR}
   SOURCES

src/lib/OpenEXRCore/openexr_config.h

@@ -14,6 +14,10 @@
 /// \addtogroup ExportMacros
 /// @{
 
+#if defined(OPENEXR_CORE_FUNCTIONS_EMBEDDED)
+#    define EXR_EXPORT OPENEXR_HIDDEN
+#else
+
 // are we making a DLL under windows (might be msvc or mingw or others)
 #if defined(OPENEXR_DLL)
 
@@ -32,6 +36,8 @@
 
 #endif
 
+#endif
+
 /*
  * MSVC does have printf format checks, but it is not in the form of a
  * function attribute, so just skip for non-GCC/clang builds