FindDevIL: Add DevIL_VERSION

This module now provides a DevIL_VERSION result variable and supports
the `<version>` argument in the find_package() call. Version range can
be also specified.

Fixes: #26858

Help/release/dev/FindDevIL.rst

@@ -0,0 +1,6 @@
+FindDevIL
+---------
+
+* The :module:`FindDevIL` module now provides a ``DevIL_VERSION`` result
+  variable and version argument and version range can be specified by
+  :command:`find_package`, when finding the DevIL package.

Modules/FindDevIL.cmake

@@ -9,7 +9,11 @@ Finds the Developer's Image Library, `DevIL <https://openil.sourceforge.net/>`_:
 
 .. code-block:: cmake
 
-  find_package(DevIL [...])
+  find_package(DevIL [<version>] [...])
+
+.. versionadded:: 4.2
+  Support for the ``<version>`` argument in the :command:`find_package`
+  call.  Version can be also specified as a range.
 
 The DevIL package internally consists of the following libraries, all
 distributed as part of the same release:
@@ -62,8 +66,13 @@ Result Variables
 This module defines the following variables:
 
 ``DevIL_FOUND``
-  Boolean indicating whether the DevIL package is found, including the IL and
-  ILU libraries.
+  Boolean indicating whether the (requested version of) DevIL package is
+  found, including the IL and ILU libraries.
+
+``DevIL_VERSION``
+  .. versionadded:: 4.2
+
+  The version of the DevIL found.
 
 ``DevIL_ILUT_FOUND``
   .. versionadded:: 3.21
@@ -113,8 +122,8 @@ Linking against the Image Library Utility Toolkit (ILUT):
   target_link_libraries(app PRIVATE DevIL::ILUT)
 #]=======================================================================]
 
-# TODO: Add version support.
-# Tested under Linux and Windows (MSVC)
+cmake_policy(PUSH)
+cmake_policy(SET CMP0159 NEW) # file(STRINGS) with REGEX updates CMAKE_MATCH_<n>
 
 include(FindPackageHandleStandardArgs)
 
@@ -123,35 +132,62 @@ find_path(IL_INCLUDE_DIR il.h
   DOC "The path to the directory that contains il.h"
 )
 
-#message("IL_INCLUDE_DIR is ${IL_INCLUDE_DIR}")
-
 find_library(IL_LIBRARIES
   NAMES IL DEVIL
   PATH_SUFFIXES libx32 lib64 lib lib32
   DOC "The file that corresponds to the base il library."
 )
 
-#message("IL_LIBRARIES is ${IL_LIBRARIES}")
-
 find_library(ILUT_LIBRARIES
   NAMES ILUT
   PATH_SUFFIXES libx32 lib64 lib lib32
   DOC "The file that corresponds to the il (system?) utility library."
 )
 
-#message("ILUT_LIBRARIES is ${ILUT_LIBRARIES}")
-
 find_library(ILU_LIBRARIES
   NAMES ILU
   PATH_SUFFIXES libx32 lib64 lib lib32
   DOC "The file that corresponds to the il utility library."
 )
 
-#message("ILU_LIBRARIES is ${ILU_LIBRARIES}")
+# Get version.
+block(PROPAGATE DevIL_VERSION)
+  if(IL_INCLUDE_DIR AND EXISTS "${IL_INCLUDE_DIR}/il.h")
+    set(regex "^[ \t]*#[ \t]*define[ \t]+IL_VERSION[ \t]+([0-9]+)[ \t]*$")
+
+    file(STRINGS ${IL_INCLUDE_DIR}/il.h result REGEX "${regex}")
+
+    if(result MATCHES "${regex}")
+      set(DevIL_VERSION "${CMAKE_MATCH_1}")
+
+      math(EXPR DevIL_VERSION_MAJOR "${DevIL_VERSION} / 100")
+      math(EXPR DevIL_VERSION_MINOR "${DevIL_VERSION} / 10 % 10")
+      math(EXPR DevIL_VERSION_PATCH "${DevIL_VERSION} % 10")
+
+      set(DevIL_VERSION "")
+      foreach(part MAJOR MINOR PATCH)
+        if(DevIL_VERSION)
+          string(APPEND ".${DevIL_VERSION_${part}}")
+        else()
+          set(DevIL_VERSION "${DevIL_VERSION_${part}}")
+        endif()
+
+        set(
+          DevIL_VERSION
+          "${DevIL_VERSION_MAJOR}.${DevIL_VERSION_MINOR}.${DevIL_VERSION_PATCH}"
+        )
+      endforeach()
+    endif()
+  endif()
+endblock()
+
+find_package_handle_standard_args(
+  DevIL
+  REQUIRED_VARS IL_LIBRARIES ILU_LIBRARIES IL_INCLUDE_DIR
+  VERSION_VAR DevIL_VERSION
+  HANDLE_VERSION_RANGE
+)
 
-find_package_handle_standard_args(DevIL DEFAULT_MSG
-                                  IL_LIBRARIES ILU_LIBRARIES
-                                  IL_INCLUDE_DIR)
 # provide legacy variable for compatibility
 set(IL_FOUND ${DevIL_FOUND})
 
@@ -187,3 +223,5 @@ if(DevIL_FOUND)
     target_link_libraries(DevIL::ILUT INTERFACE DevIL::ILU)
   endif()
 endif()
+
+cmake_policy(POP)

Tests/CMakeOnly/AllFindModules/CMakeLists.txt

@@ -115,7 +115,7 @@ foreach(
     ALSA Armadillo
     BISON Boost BZip2 BZIP2
     CUDA Cups
-    Doxygen DOXYGEN
+    DevIL Doxygen DOXYGEN
     EXPAT
     FLEX Freetype
     Gettext GIF GTK2

Tests/FindDevIL/Test/CMakeLists.txt

@@ -4,19 +4,21 @@ include(CTest)
 
 find_package(DevIL)
 
-#FIXME: check version too.
-# add_definitions(
-#  -DCMAKE_EXPECTED_SDL_VERSION_MAJOR=${SDL_VERSION_MAJOR}
-#  -DCMAKE_EXPECTED_SDL_VERSION_MINOR=${SDL_VERSION_MINOR}
-#  -DCMAKE_EXPECTED_SDL_VERSION_PATCH=${SDL_VERSION_PATCH})
-
 add_executable(test_devil_var main.c)
 target_include_directories(test_devil_var PRIVATE ${IL_INCLUDE_DIRS})
 target_link_libraries(test_devil_var PRIVATE ${IL_LIBRARIES})
+target_compile_definitions(
+  test_devil_var
+  PRIVATE CMAKE_EXPECTED_DEVIL_VERSION="${DevIL_VERSION}"
+)
 add_test(NAME test_devil_var COMMAND test_devil_var)
 
 add_executable(test_devil_il_tgt main.c)
 target_link_libraries(test_devil_il_tgt DevIL::IL)
+target_compile_definitions(
+  test_devil_il_tgt
+  PRIVATE CMAKE_EXPECTED_DEVIL_VERSION="${DevIL_VERSION}"
+)
 add_test(NAME test_devil_il_tgt COMMAND test_devil_il_tgt)
 
 add_executable(test_devil_ilu_tgt main_ilu.c)

Tests/FindDevIL/Test/main.c

@@ -1,4 +1,6 @@
 #include <IL/il.h>
+#include <stdio.h>
+#include <string.h>
 
 int main(void)
 {
@@ -6,5 +8,16 @@ int main(void)
   ilInit();
 
   ilShutDown();
-  return 0;
+
+  int version = IL_VERSION;
+  int major = version / 100;
+  int minor = version / 10 % 10;
+  int patch = version % 10;
+  char version_string[100];
+  snprintf(version_string, sizeof(version_string), "%d.%d.%d", major, minor,
+           patch);
+
+  printf("Found DevIL version %s, expected version %s\n", version_string,
+         CMAKE_EXPECTED_DEVIL_VERSION);
+  return strcmp(version_string, CMAKE_EXPECTED_DEVIL_VERSION);
 }