Use zlib target instead of ZLIB_INCLUDE_DIRS and ZLIB_LIBRARIES

Currently, when one target needs zlib as a dependency, it needs to use both ocv_include_directories and target_link_libraries. However in modern CMake, only target_link_libraries is needed if zlib has a target_include_directories. In this patch, if zlib is found by find_package, an ALIAS target zlib will be created. CMake >= 3.1 ensures a target ZLIB::ZLIB. https://cmake.org/cmake/help/latest/module/FindZLIB.html If zlib is built, an library target zlib will be created.
opencv · May 11, 2024 · bb70678 · bb70678
1 parent 5bd64e0
commit bb70678
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Showing 11 changed files with 45 additions and 76 deletions.
diff --git a/3rdparty/libpng/CMakeLists.txt b/3rdparty/libpng/CMakeLists.txt
@@ -22,7 +22,7 @@ else()
   set(M_LIBRARY "")
 endif()
 
-ocv_include_directories("${CMAKE_CURRENT_SOURCE_DIR}" ${ZLIB_INCLUDE_DIRS})
+ocv_include_directories("${CMAKE_CURRENT_SOURCE_DIR}")
 
 file(GLOB lib_srcs *.c)
 file(GLOB lib_hdrs *.h)
@@ -75,7 +75,7 @@ if(MSVC)
 endif(MSVC)
 
 add_library(${PNG_LIBRARY} STATIC ${OPENCV_3RDPARTY_EXCLUDE_FROM_ALL} ${lib_srcs} ${lib_hdrs})
-target_link_libraries(${PNG_LIBRARY} ${ZLIB_LIBRARIES})
+target_link_libraries(${PNG_LIBRARY} zlib)
 
 ocv_warnings_disable(CMAKE_C_FLAGS -Wundef -Wcast-align -Wimplicit-fallthrough -Wunused-parameter -Wsign-compare
     -Wmaybe-uninitialized

diff --git a/3rdparty/libspng/CMakeLists.txt b/3rdparty/libspng/CMakeLists.txt
@@ -7,7 +7,6 @@ project(${SPNG_LIBRARY})
 
 set(CURR_INCLUDE_DIR "${CMAKE_CURRENT_LIST_DIR}")
 set_property(GLOBAL PROPERTY SPNG_INCLUDE_DIR ${CURR_INCLUDE_DIR})
-ocv_include_directories(${ZLIB_INCLUDE_DIRS})
 
 file(GLOB_RECURSE spng_headers RELATIVE "${CMAKE_CURRENT_LIST_DIR}" "*.h")
 file(GLOB_RECURSE spng_sources RELATIVE "${CMAKE_CURRENT_LIST_DIR}" "*.c")
@@ -23,7 +22,7 @@ if(MSVC)
 endif(MSVC)
 
 add_library(${SPNG_LIBRARY} STATIC ${OPENCV_3RDPARTY_EXCLUDE_FROM_ALL} ${spng_headers} ${spng_sources})
-target_link_libraries(${SPNG_LIBRARY} ${ZLIB_LIBRARIES})
+target_link_libraries(${SPNG_LIBRARY} zlib)
 
 set_target_properties(${SPNG_LIBRARY}
         PROPERTIES OUTPUT_NAME ${SPNG_LIBRARY}

diff --git a/3rdparty/libtiff/CMakeLists.txt b/3rdparty/libtiff/CMakeLists.txt
@@ -272,13 +272,6 @@ set(LOGLUV_SUPPORT ${logluv})
 option(mdi "support for Microsoft Document Imaging" ON)
 set(MDI_SUPPORT ${mdi})
 
-# ZLIB
-set(ZLIB_SUPPORT 0)
-if(ZLIB_LIBRARY)
-  set(ZLIB_SUPPORT 1)
-endif()
-set(ZIP_SUPPORT ${ZLIB_SUPPORT})
-
 set(PIXARLOG_SUPPORT FALSE)
 
 # JPEG
@@ -341,9 +334,6 @@ set(TIFF_LIBRARY_DEPS)
 if(M_LIBRARY)
   list(APPEND TIFF_LIBRARY_DEPS ${M_LIBRARY})
 endif()
-if(ZLIB_LIBRARIES)
-  list(APPEND TIFF_LIBRARY_DEPS ${ZLIB_LIBRARIES})
-endif()
 if(JPEG_LIBRARIES)
   list(APPEND TIFF_LIBRARY_DEPS ${JPEG_LIBRARIES})
 endif()
@@ -375,7 +365,7 @@ configure_file("${CMAKE_CURRENT_SOURCE_DIR}/tiffvers.h.cmake.in"
                "${CMAKE_CURRENT_BINARY_DIR}/tiffvers.h"
                @ONLY)
 
-ocv_include_directories("${CMAKE_CURRENT_SOURCE_DIR}" "${CMAKE_CURRENT_BINARY_DIR}" ${ZLIB_INCLUDE_DIRS})
+ocv_include_directories("${CMAKE_CURRENT_SOURCE_DIR}" "${CMAKE_CURRENT_BINARY_DIR}")
 
 set(lib_srcs
     tif_aux.c

diff --git a/3rdparty/openexr/CMakeLists.txt b/3rdparty/openexr/CMakeLists.txt
@@ -86,7 +86,7 @@ set(OPENEXR_INCLUDE_PATHS "${CMAKE_CURRENT_SOURCE_DIR}/Half"
                           "${CMAKE_CURRENT_SOURCE_DIR}/IlmImf"
                           "${CMAKE_CURRENT_BINARY_DIR}")
 
-ocv_include_directories("${CMAKE_CURRENT_BINARY_DIR}" ${ZLIB_INCLUDE_DIRS} ${OPENEXR_INCLUDE_PATHS})
+ocv_include_directories("${CMAKE_CURRENT_BINARY_DIR}" ${OPENEXR_INCLUDE_PATHS})
 
 file(GLOB lib_srcs Half/half.cpp Iex/*.cpp IlmThread/*.cpp Imath/*.cpp IlmImf/*.cpp)
 file(GLOB lib_hdrs Half/*.h Iex/Iex*.h IlmThread/IlmThread*.h Imath/Imath*.h IlmImf/*.h)
@@ -128,7 +128,7 @@ if(MSVC AND CV_ICC)
 endif()
 
 add_library(IlmImf STATIC ${OPENCV_3RDPARTY_EXCLUDE_FROM_ALL} ${lib_hdrs} ${lib_srcs})
-target_link_libraries(IlmImf ${ZLIB_LIBRARIES})
+target_link_libraries(IlmImf zlib)
 
 set_target_properties(IlmImf
     PROPERTIES

diff --git a/3rdparty/zlib-ng/CMakeLists.txt b/3rdparty/zlib-ng/CMakeLists.txt
@@ -1,4 +1,4 @@
-project(${ZLIB_LIBRARY} LANGUAGES C)
+project(zlib LANGUAGES C)
 
 if("c_std_11" IN_LIST CMAKE_C_COMPILE_FEATURES)
   set(CMAKE_C_STANDARD 11)          # The C standard whose features are requested to build this target
@@ -123,10 +123,10 @@ elseif(CMAKE_C_COMPILER_ID MATCHES "GNU" OR CMAKE_C_COMPILER_ID MATCHES "Clang")
         set(CMAKE_REQUIRED_FLAGS)
       endif()
       if(FLOATABI)
-        message(STATUS "${ZLIB_LIBRARY} ARM floating point arch: ${FLOATABI}")
+        message(STATUS "zlib ARM floating point arch: ${FLOATABI}")
         add_compile_options(${FLOATABI})
       else()
-        message(STATUS "${ZLIB_LIBRARY} ARM floating point arch not auto-detected")
+        message(STATUS "zlib ARM floating point arch not auto-detected")
       endif()
     endif()
   endif()
@@ -777,20 +777,20 @@ ocv_warnings_disable(CMAKE_C_FLAGS -Wmissing-prototypes
   -Wmissing-declarations
 )
 
-set_target_properties(${ZLIB_LIBRARY} PROPERTIES
-  OUTPUT_NAME ${ZLIB_LIBRARY}
+set_target_properties(zlib PROPERTIES
+  OUTPUT_NAME "zlib"
   DEBUG_POSTFIX "${OPENCV_DEBUG_POSTFIX}"
-  COMPILE_PDB_NAME ${ZLIB_LIBRARY}
-  COMPILE_PDB_NAME_DEBUG "${ZLIB_LIBRARY}${OPENCV_DEBUG_POSTFIX}"
+  COMPILE_PDB_NAME "zlib"
+  COMPILE_PDB_NAME_DEBUG "zlib${OPENCV_DEBUG_POSTFIX}"
   ARCHIVE_OUTPUT_DIRECTORY ${3P_LIBRARY_OUTPUT_PATH}
 )
 
 if(ENABLE_SOLUTION_FOLDERS)
-  set_target_properties(${ZLIB_LIBRARY} PROPERTIES FOLDER "3rdparty")
+  set_target_properties(zlib PROPERTIES FOLDER "3rdparty")
 endif()
 
 if(NOT BUILD_SHARED_LIBS)
-  ocv_install_target(${ZLIB_LIBRARY} EXPORT OpenCVModules ARCHIVE DESTINATION ${OPENCV_3P_LIB_INSTALL_PATH} COMPONENT dev)
+  ocv_install_target(zlib EXPORT OpenCVModules ARCHIVE DESTINATION ${OPENCV_3P_LIB_INSTALL_PATH} COMPONENT dev)
 endif()
 
-ocv_install_3rdparty_licenses(${ZLIB_LIBRARY} LICENSE.md)
+ocv_install_3rdparty_licenses(zlib LICENSE.md)
diff --git a/3rdparty/zlib/CMakeLists.txt b/3rdparty/zlib/CMakeLists.txt
@@ -3,7 +3,7 @@
 #
 # ----------------------------------------------------------------------------
 
-project(${ZLIB_LIBRARY} C)
+project(zlib C)
 
 include(CheckFunctionExists)
 include(CheckIncludeFile)
@@ -41,8 +41,6 @@ endif()
 configure_file(	${CMAKE_CURRENT_SOURCE_DIR}/zconf.h.cmakein
                 ${CMAKE_CURRENT_BINARY_DIR}/zconf.h @ONLY)
 
-ocv_include_directories("${CMAKE_CURRENT_SOURCE_DIR}" "${CMAKE_CURRENT_BINARY_DIR}")
-
 set(ZLIB_PUBLIC_HDRS
     ${CMAKE_CURRENT_BINARY_DIR}/zconf.h
     zlib.h
@@ -76,8 +74,9 @@ set(ZLIB_SRCS
     zutil.c
 )
 
-add_library(${ZLIB_LIBRARY} STATIC ${OPENCV_3RDPARTY_EXCLUDE_FROM_ALL} ${ZLIB_SRCS} ${ZLIB_PUBLIC_HDRS} ${ZLIB_PRIVATE_HDRS})
-set_target_properties(${ZLIB_LIBRARY} PROPERTIES DEFINE_SYMBOL ZLIB_DLL)
+add_library(zlib STATIC ${OPENCV_3RDPARTY_EXCLUDE_FROM_ALL} ${ZLIB_SRCS} ${ZLIB_PUBLIC_HDRS} ${ZLIB_PRIVATE_HDRS})
+target_include_directories(zlib PUBLIC ${CMAKE_CURRENT_BINARY_DIR} ${CMAKE_CURRENT_SOURCE_DIR})
+set_target_properties(zlib PROPERTIES DEFINE_SYMBOL ZLIB_DLL)
 
 ocv_warnings_disable(CMAKE_C_FLAGS -Wshorten-64-to-32 -Wattributes -Wstrict-prototypes -Wmissing-prototypes -Wmissing-declarations -Wshift-negative-value
     -Wundef  # _LFS64_LARGEFILE is not defined
@@ -86,20 +85,20 @@ ocv_warnings_disable(CMAKE_C_FLAGS -Wshorten-64-to-32 -Wattributes -Wstrict-prot
     /wd4244  # MSVS + zlib 1.2.12: warning C4244: '=': conversion from 'ush' to 'uchf', possible loss of data
 )
 
-set_target_properties(${ZLIB_LIBRARY} PROPERTIES
-    OUTPUT_NAME ${ZLIB_LIBRARY}
+set_target_properties(zlib PROPERTIES
+    OUTPUT_NAME "zlib"
     DEBUG_POSTFIX "${OPENCV_DEBUG_POSTFIX}"
-    COMPILE_PDB_NAME ${ZLIB_LIBRARY}
-    COMPILE_PDB_NAME_DEBUG "${ZLIB_LIBRARY}${OPENCV_DEBUG_POSTFIX}"
+    COMPILE_PDB_NAME "zlib"
+    COMPILE_PDB_NAME_DEBUG "zlib${OPENCV_DEBUG_POSTFIX}"
     ARCHIVE_OUTPUT_DIRECTORY ${3P_LIBRARY_OUTPUT_PATH}
 )
 
 if(ENABLE_SOLUTION_FOLDERS)
-  set_target_properties(${ZLIB_LIBRARY} PROPERTIES FOLDER "3rdparty")
+  set_target_properties(zlib PROPERTIES FOLDER "3rdparty")
 endif()
 
 if(NOT BUILD_SHARED_LIBS)
-  ocv_install_target(${ZLIB_LIBRARY} EXPORT OpenCVModules ARCHIVE DESTINATION ${OPENCV_3P_LIB_INSTALL_PATH} COMPONENT dev)
+  ocv_install_target(zlib EXPORT OpenCVModules ARCHIVE DESTINATION ${OPENCV_3P_LIB_INSTALL_PATH} COMPONENT dev)
 endif()
 
 ocv_install_3rdparty_licenses(zlib LICENSE)
diff --git a/CMakeLists.txt b/CMakeLists.txt
@@ -1430,7 +1430,7 @@ status("  Media I/O: ")
 if(WITH_ZLIB_NG OR HAVE_ZLIB_NG)
   status("    ZLib-Ng:" "build (zlib ver ${ZLIB_VERSION_STRING}, zlib-ng ver ${ZLIBNG_VERSION_STRING})")
 else()
-  status("    ZLib:"   ZLIB_FOUND THEN "${ZLIB_LIBRARIES} (ver ${ZLIB_VERSION_STRING})" ELSE "build (ver ${ZLIB_VERSION_STRING})")
+  status("    ZLib:"   ZLIB_FOUND THEN "zlib (ver ${ZLIB_VERSION_STRING})" ELSE "build (ver ${ZLIB_VERSION_STRING})")
 endif()
 
 if(WITH_JPEG OR HAVE_JPEG)

diff --git a/cmake/OpenCVFindLibsGrfmt.cmake b/cmake/OpenCVFindLibsGrfmt.cmake
@@ -4,50 +4,33 @@
 
 # --- zlib (required) ---
 if(WITH_ZLIB_NG)
-  ocv_clear_vars(ZLIB_LIBRARY ZLIB_LIBRARIES ZLIB_INCLUDE_DIR)
-  set(ZLIB_LIBRARY zlib CACHE INTERNAL "")
   add_subdirectory("${OpenCV_SOURCE_DIR}/3rdparty/zlib-ng")
-  set(ZLIB_INCLUDE_DIR "${${ZLIB_LIBRARY}_BINARY_DIR}" CACHE INTERNAL "")
-  set(ZLIB_INCLUDE_DIRS ${ZLIB_INCLUDE_DIR})
-  set(ZLIB_LIBRARIES ${ZLIB_LIBRARY})
 
-  ocv_parse_header_version(ZLIB "${${ZLIB_LIBRARY}_SOURCE_DIR}/zlib.h.in" ZLIB_VERSION)
-  ocv_parse_header_version(ZLIBNG "${${ZLIB_LIBRARY}_SOURCE_DIR}/zlib.h.in" ZLIBNG_VERSION)
+  ocv_parse_header_version(ZLIB "${zlib_SOURCE_DIR}/zlib.h.in" ZLIB_VERSION)
+  ocv_parse_header_version(ZLIBNG "${zlib_SOURCE_DIR}/zlib.h.in" ZLIBNG_VERSION)
 
   set(HAVE_ZLIB_NG YES)
 else()
   if(BUILD_ZLIB)
     ocv_clear_vars(ZLIB_FOUND)
   else()
-    ocv_clear_internal_cache_vars(ZLIB_LIBRARY ZLIB_INCLUDE_DIR)
-  if(ANDROID)
-    set(_zlib_ORIG_CMAKE_FIND_LIBRARY_SUFFIXES ${CMAKE_FIND_LIBRARY_SUFFIXES})
-    set(CMAKE_FIND_LIBRARY_SUFFIXES .so)
-  endif()
-  find_package(ZLIB "${MIN_VER_ZLIB}")
-  if(ANDROID)
-    set(CMAKE_FIND_LIBRARY_SUFFIXES ${_zlib_ORIG_CMAKE_FIND_LIBRARY_SUFFIXES})
-    unset(_zlib_ORIG_CMAKE_FIND_LIBRARY_SUFFIXES)
-  endif()
-  if(ZLIB_FOUND AND ANDROID)
-    if(ZLIB_LIBRARY MATCHES "/usr/lib.*/libz.so$")
-      set(ZLIB_LIBRARY z)
-      set(ZLIB_LIBRARIES z)
-      set(ZLIB_LIBRARY_RELEASE z)
+    if(ANDROID)
+      set(_zlib_ORIG_CMAKE_FIND_LIBRARY_SUFFIXES ${CMAKE_FIND_LIBRARY_SUFFIXES})
+      set(CMAKE_FIND_LIBRARY_SUFFIXES .so)
+    endif()
+    find_package(ZLIB "${MIN_VER_ZLIB}")
+    if(ANDROID)
+      set(CMAKE_FIND_LIBRARY_SUFFIXES ${_zlib_ORIG_CMAKE_FIND_LIBRARY_SUFFIXES})
+      unset(_zlib_ORIG_CMAKE_FIND_LIBRARY_SUFFIXES)
     endif()
   endif()
-  endif()
-
-  if(NOT ZLIB_FOUND)
-    ocv_clear_vars(ZLIB_LIBRARY ZLIB_LIBRARIES ZLIB_INCLUDE_DIR)
 
-    set(ZLIB_LIBRARY zlib CACHE INTERNAL "")
+  if(ZLIB_FOUND)
+    add_library(zlib ALIAS ZLIB::ZLIB)
+  else()
     add_subdirectory("${OpenCV_SOURCE_DIR}/3rdparty/zlib")
-    set(ZLIB_INCLUDE_DIR "${${ZLIB_LIBRARY}_SOURCE_DIR}" "${${ZLIB_LIBRARY}_BINARY_DIR}" CACHE INTERNAL "")
-    set(ZLIB_INCLUDE_DIRS ${ZLIB_INCLUDE_DIR})
-    set(ZLIB_LIBRARIES ${ZLIB_LIBRARY})
 
-    ocv_parse_header_version(ZLIB "${${ZLIB_LIBRARY}_SOURCE_DIR}/zlib.h" ZLIB_VERSION)
+    ocv_parse_header_version(ZLIB "${zlib_SOURCE_DIR}/zlib.h" ZLIB_VERSION)
   endif()
 endif()
 

diff --git a/modules/core/CMakeLists.txt b/modules/core/CMakeLists.txt
@@ -95,7 +95,7 @@ source_group("Src" FILES "${OPENCV_MODULE_opencv_core_BINARY_DIR}/version_string
 ocv_glob_module_sources(SOURCES "${OPENCV_MODULE_opencv_core_BINARY_DIR}/version_string.inc"
                         HEADERS ${core_parallel_hdrs} ${module_opencl_hdrs} ${lib_cuda_hdrs} ${lib_cuda_hdrs_detail})
 
-ocv_module_include_directories(${the_module} ${ZLIB_INCLUDE_DIRS} ${OPENCL_INCLUDE_DIRS})
+ocv_module_include_directories(${the_module} ${OPENCL_INCLUDE_DIRS})
 if(ANDROID AND HAVE_CPUFEATURES)
   ocv_append_source_file_compile_definitions(${CMAKE_CURRENT_SOURCE_DIR}/src/system.cpp "HAVE_CPUFEATURES=1")
   ocv_module_include_directories(${CPUFEATURES_INCLUDE_DIRS})
@@ -166,7 +166,7 @@ endif()
 ocv_create_module(${extra_libs})
 
 ocv_target_link_libraries(${the_module} PRIVATE
-    "${ZLIB_LIBRARIES}" "${OPENCL_LIBRARIES}" "${VA_LIBRARIES}"
+    "zlib" "${OPENCL_LIBRARIES}" "${VA_LIBRARIES}"
     "${OPENGL_LIBRARIES}"
     "${GLX_LIBRARIES}"
     "${LAPACK_LIBRARIES}" "${CPUFEATURES_LIBRARIES}" "${HALIDE_LIBRARIES}"

diff --git a/modules/highgui/CMakeLists.txt b/modules/highgui/CMakeLists.txt
@@ -31,8 +31,7 @@ if(DEFINED WINRT AND NOT DEFINED ENABLE_WINRT_MODE_NATIVE)
 endif()
 
 if(APPLE)
-  ocv_include_directories(${ZLIB_INCLUDE_DIRS})
-  list(APPEND HIGHGUI_LIBRARIES ${ZLIB_LIBRARIES})
+  list(APPEND HIGHGUI_LIBRARIES zlib)
 endif()
 
 if(HAVE_WEBP)

diff --git a/modules/imgcodecs/CMakeLists.txt b/modules/imgcodecs/CMakeLists.txt
@@ -79,8 +79,7 @@ if(HAVE_OPENEXR)
 endif()
 
 if(HAVE_PNG OR HAVE_TIFF OR HAVE_OPENEXR OR HAVE_SPNG)
-  ocv_include_directories(${ZLIB_INCLUDE_DIRS})
-  list(APPEND GRFMT_LIBS ${ZLIB_LIBRARIES})
+  list(APPEND GRFMT_LIBS zlib)
 endif()
 
 if(HAVE_GDAL)