CMake: Fixes for yaml-cpp and generated config (#1823)

* Use `TARGET` for the config if-statements.

The check would always evaluate to true otherwise.

Signed-off-by: Pierre Wendling <pierre.wendling.4@gmail.com>

* Use PACKAGE_PREFIX_DIR from PACKAGE_INIT.

This avoids guessing the path to the prefix.

Signed-off-by: Pierre Wendling <pierre.wendling.4@gmail.com>

* Add compatibility with yaml-cpp 0.8.0 target.

The target was renamed to `yaml-cpp::yaml-cpp`, which breaks when using
the upstream CMake package over the Find module.

Signed-off-by: Pierre Wendling <pierre.wendling.4@gmail.com>

---------

Signed-off-by: Pierre Wendling <pierre.wendling.4@gmail.com>
Co-authored-by: Rémi Achard <remiachard@gmail.com>
Co-authored-by: Doug Walker <doug.walker@autodesk.com>

Author: 3 people

share/cmake/modules/Findyaml-cpp.cmake

@@ -12,6 +12,11 @@
 # Global targets defined by this module:
 #   yaml-cpp
 #
+# For compatibility with the upstream CMake package, the following variables and targets are defined:
+#   yaml-cpp::yaml-cpp      - Alias of the yaml-cpp target
+#   YAML_CPP_LIBRARIES      - Libraries to link against yaml-cpp
+#   YAML_CPP_INCLUDE_DIR    - Include directory
+#
 # Usually CMake will use the dynamic library rather than static, if both are present. 
 # In this case, you may set yaml-cpp_STATIC_LIBRARY to ON to request use of the static one. 
 # If only the static library is present (such as when OCIO builds the dependency), then the option 
@@ -147,4 +152,17 @@ if(_yaml-cpp_TARGET_CREATE)
     )
 
     mark_as_advanced(yaml-cpp_INCLUDE_DIR yaml-cpp_LIBRARY yaml-cpp_VERSION)
-endif()
+endif()
+
+###############################################################################
+### Set variables for compatibility ###
+
+if(TARGET yaml-cpp AND NOT TARGET yaml-cpp::yaml-cpp)
+    add_library(yaml-cpp::yaml-cpp ALIAS yaml-cpp)
+endif()
+
+if(yaml-cpp_INCLUDE_DIR)
+    set(YAML_CPP_INCLUDE_DIR "${yaml-cpp_INCLUDE_DIR}")
+endif()
+
+set(YAML_CPP_LIBRARIES yaml-cpp::yaml-cpp)

share/cmake/modules/install/Installyaml-cpp.cmake

@@ -12,6 +12,11 @@
 # Global targets defined by this module:
 #   yaml-cpp::yaml-cpp         
 #
+# For compatibility with the upstream CMake package, the following variables and targets are defined:
+#   yaml-cpp::yaml-cpp      - Alias of the yaml-cpp target
+#   YAML_CPP_LIBRARIES      - Libraries to link against yaml-cpp
+#   YAML_CPP_INCLUDE_DIR    - Include directory
+#
 
 ###############################################################################
 ### Create target (if previous 'find_package' call hasn't) ###
@@ -151,3 +156,16 @@ if(_yaml-cpp_TARGET_CREATE)
 
     mark_as_advanced(yaml-cpp_INCLUDE_DIR yaml-cpp_LIBRARY yaml-cpp_VERSION)
 endif()
+
+###############################################################################
+### Set variables for compatibility ###
+
+if(TARGET yaml-cpp AND NOT TARGET yaml-cpp::yaml-cpp)
+    add_library(yaml-cpp::yaml-cpp ALIAS yaml-cpp)
+endif()
+
+if(yaml-cpp_INCLUDE_DIR)
+    set(YAML_CPP_INCLUDE_DIR "${yaml-cpp_INCLUDE_DIR}")
+endif()
+
+set(YAML_CPP_LIBRARIES yaml-cpp::yaml-cpp)

src/OpenColorIO/CMakeLists.txt

@@ -307,7 +307,7 @@ target_link_libraries(OpenColorIO
         "$<BUILD_INTERFACE:utils::from_chars>"
         "$<BUILD_INTERFACE:utils::strings>"
         "$<BUILD_INTERFACE:xxHash>"
-        yaml-cpp
+        ${YAML_CPP_LIBRARIES}
         MINIZIP::minizip-ng
 )
 

src/cmake/Config.cmake.in

@@ -14,43 +14,31 @@ if (NOT @BUILD_SHARED_LIBS@) # NOT @BUILD_SHARED_LIBS@
         set(CMAKE_FIND_APPBUNDLE LAST)
     endif()
 
-    # Get the install directory.
-    set(_IMPORT_PREFIX "${CMAKE_CURRENT_LIST_DIR}")
-    # Get the install directory. Since the current file is under 
-    # <install directory>/lib/cmake/OpenColorIO going back three directory.
-    foreach(i RANGE 1 3)
-        get_filename_component(_IMPORT_PREFIX "${_IMPORT_PREFIX}" PATH)
-        if(_IMPORT_PREFIX STREQUAL "/")
-        set(_IMPORT_PREFIX "")
-        break()
-        endif()
-    endforeach()
-
     # Append OCIO custom find module path.
-    list(APPEND CMAKE_MODULE_PATH "${_IMPORT_PREFIX}/share/OpenColorIO/cmake/modules")
-    list(APPEND CMAKE_MODULE_PATH "${_IMPORT_PREFIX}/share/OpenColorIO/cmake/macros")
+    list(APPEND CMAKE_MODULE_PATH "${PACKAGE_PREFIX_DIR}/share/OpenColorIO/cmake/modules")
+    list(APPEND CMAKE_MODULE_PATH "${PACKAGE_PREFIX_DIR}/share/OpenColorIO/cmake/macros")
 
     ########################
     # Required dependencies 
     ########################
 
-    if (NOT expat::expat)
+    if (NOT TARGET expat::expat)
         find_dependency(expat @expat_VERSION@)
     endif()
 
-    if (NOT Imath::Imath)
+    if (NOT TARGET Imath::Imath)
         find_dependency(Imath @Imath_VERSION@)
     endif()
 
-    if (NOT pystring::pystring)
+    if (NOT TARGET pystring::pystring)
         find_dependency(pystring @pystring_VERSION@)
     endif()
 
-    if (NOT yaml-cpp)
+    if (NOT TARGET yaml-cpp AND NOT TARGET yaml-cpp::yaml-cpp)
         find_dependency(yaml-cpp @yaml-cpp_VERSION@)
     endif()
 
-    if (NOT ZLIB::ZLIB)
+    if (NOT TARGET ZLIB::ZLIB)
         # ZLIB_VERSION is available starting CMake 3.26+.
         # ZLIB_VERSION_STRING is still available for backward compatibility.
         # See https://cmake.org/cmake/help/git-stage/module/FindZLIB.html
@@ -62,7 +50,7 @@ if (NOT @BUILD_SHARED_LIBS@) # NOT @BUILD_SHARED_LIBS@
         endif()
     endif()
 
-    if (NOT MINIZIP::minizip-ng)
+    if (NOT TARGET MINIZIP::minizip-ng)
         find_dependency(minizip-ng @minizip-ng_VERSION@)
     endif()
 

tests/cpu/CMakeLists.txt

@@ -35,7 +35,7 @@ function(add_ocio_test NAME SOURCES PRIVATE_INCLUDES)
             sampleicc::sampleicc
             unittest_data
             utils::strings
-            yaml-cpp
+            ${YAML_CPP_LIBRARIES}
             testutils
             MINIZIP::minizip-ng
             xxHash