From 414f953d8195b3dc72341d9394211284871a63e5 Mon Sep 17 00:00:00 2001
From: Larry Gritz <lg@larrygritz.com>
Date: Mon, 19 Feb 2024 16:49:18 -0800
Subject: [PATCH] build: Fixes for DCMTK (#4147)

It somehow escaped our notice, but not only does DCMTK have an exported
config, but also CMake itself has a FindDCMTK.cmake module. So get rid
of ours, and prefer the config if available. This is hoped to solve some
edge cases for finding and using this library properly.

Fixes #4146
(I hope?)

Signed-off-by: Larry Gritz <lg@larrygritz.com>
---
 src/cmake/Config.cmake.in         |  3 ++
 src/cmake/externalpackages.cmake  |  5 ++-
 src/cmake/modules/FindDCMTK.cmake | 72 -------------------------------
 src/dicom.imageio/CMakeLists.txt  |  3 +-
 4 files changed, 8 insertions(+), 75 deletions(-)
 delete mode 100644 src/cmake/modules/FindDCMTK.cmake

diff --git a/src/cmake/Config.cmake.in b/src/cmake/Config.cmake.in
index 5fd155728f..0ee290b4d4 100644
--- a/src/cmake/Config.cmake.in
+++ b/src/cmake/Config.cmake.in
@@ -36,6 +36,9 @@ if (NOT @BUILD_SHARED_LIBS@)
     if (@PNG_FOUND@)
         find_dependency(PNG)
     endif()
+    if (@DCMTK_FOUND@)
+        find_dependency(DCMTK)
+    endif()
     # The following have the same problem except that INTERFACE_LINK_LIBRARIES use
     # TARGET_NAME_IF_EXISTS, so the error only happens on link time.
     if (@OIIO_TBB@)
diff --git a/src/cmake/externalpackages.cmake b/src/cmake/externalpackages.cmake
index 241456725d..4068330fb2 100644
--- a/src/cmake/externalpackages.cmake
+++ b/src/cmake/externalpackages.cmake
@@ -200,7 +200,10 @@ checked_find_package (TBB 2017
                       SETVARIABLES OIIO_TBB
                       PREFER_CONFIG)
 
-checked_find_package (DCMTK VERSION_MIN 3.6.1)  # For DICOM images
+# DCMTK is used to read DICOM images
+checked_find_package (DCMTK VERSION_MIN 3.6.1
+                      PREFER_CONFIG)
+
 checked_find_package (FFmpeg VERSION_MIN 3.0)
 checked_find_package (GIF
                       VERSION_MIN 4
diff --git a/src/cmake/modules/FindDCMTK.cmake b/src/cmake/modules/FindDCMTK.cmake
deleted file mode 100644
index 8f9e434066..0000000000
--- a/src/cmake/modules/FindDCMTK.cmake
+++ /dev/null
@@ -1,72 +0,0 @@
-# Module to find DCMTK
-#
-# Copyright Contributors to the OpenImageIO project.
-# SPDX-License-Identifier: Apache-2.0
-# https://github.com/AcademySoftwareFoundation/OpenImageIO
-#
-# This module will first look into the directories defined by the variables:
-#   - DCMTK_ROOT, DCMTK_INCLUDE_PATH, DCMTK_LIBRARY_PATH
-#
-# This module defines the following variables:
-#
-# DCMTK_FOUND            True if DCMTK was found.
-# DCMTK_INCLUDES         Where to find DCMTK headers
-# DCMTK_LIBRARIES        List of libraries to link against when using DCMTK
-# DCMTK_VERSION          Version of DCMTK (e.g., 3.6.2)
-# DCMTK_VERSION_NUMBER   Int version of DCMTK (e.g., 362 for 3.6.2)
-
-include (FindPackageHandleStandardArgs)
-include (FindPackageMessage)
-
-if (NOT DCMTK_FIND_QUIETLY)
-    if (DCMTK_ROOT)
-        message(STATUS "DCMTK path explicitly specified: ${DCMTK_ROOT}")
-    endif()
-    if (DCMTK_INCLUDE_PATH)
-        message(STATUS "DCMTK INCLUDE_PATH explicitly specified: ${DCMTK_INCLUDE_PATH}")
-    endif()
-    if (DCMTK_LIBRARY_PATH)
-        message(STATUS "DCMTK LIBRARY_PATH explicitly specified: ${DCMTK_LIBRARY_PATH}")
-    endif()
-endif ()
-
-find_path (DCMTK_INCLUDE_DIR
-    dcmtk/dcmdata/dcuid.h
-    HINTS
-      ${DCMTK_INCLUDE_PATH}  ENV DCMTK_INCLUDE_PATH
-    DOC "The directory where DCMTK headers reside")
-
-foreach (COMPONENT dcmimage dcmimgle dcmdata oflog ofstd iconv)
-    find_library (DCMTK_${COMPONENT}_LIB ${COMPONENT}
-                  HINTS
-                    ${DCMTK_LIBRARY_PATH}  ENV DCMTK_LIBRARY_PATH
-                  PATH_SUFFIXES lib lib64
-                  )
-    if (DCMTK_${COMPONENT}_LIB)
-        set (DCMTK_LIBRARIES ${DCMTK_LIBRARIES} ${DCMTK_${COMPONENT}_LIB})
-    endif ()
-endforeach()
-
-if (DCMTK_INCLUDE_DIR AND EXISTS "${DCMTK_INCLUDE_DIR}/dcmtk/config/osconfig.h")
-    file(STRINGS "${DCMTK_INCLUDE_DIR}/dcmtk/config/osconfig.h" TMP REGEX "^#define PACKAGE_VERSION[ \t].*$")
-    string(REGEX MATCHALL "[0-9.]+" DCMTK_VERSION ${TMP})
-    file(STRINGS "${DCMTK_INCLUDE_DIR}/dcmtk/config/osconfig.h" TMP REGEX "^#define PACKAGE_VERSION_NUMBER[ \t].*$")
-    string(REGEX MATCHALL "[0-9.]+" DCMTK_VERSION_NUMBER ${TMP})
-endif ()
-
-include (FindPackageHandleStandardArgs)
-find_package_handle_standard_args (DCMTK
-    REQUIRED_VARS   DCMTK_INCLUDE_DIR DCMTK_LIBRARIES
-    VERSION_VAR     DCMTK_VERSION
-    )
-
-if (DCMTK_FOUND)
-    set(DCMTK_INCLUDES "${DCMTK_INCLUDE_DIR}")
-endif()
-
-mark_as_advanced (
-    DCMTK_INCLUDE_DIR
-    DCMTK_LIBRARIES
-    DCMTK_VERSION
-    DCMTK_VERSION_NUMBER
-    )
diff --git a/src/dicom.imageio/CMakeLists.txt b/src/dicom.imageio/CMakeLists.txt
index 6631a4d1bf..e8a2fbbb7a 100644
--- a/src/dicom.imageio/CMakeLists.txt
+++ b/src/dicom.imageio/CMakeLists.txt
@@ -4,8 +4,7 @@
 
 if (DCMTK_FOUND)
     add_oiio_plugin (dicominput.cpp
-                     INCLUDE_DIRS ${DCMTK_INCLUDE_DIR}
-                     LINK_LIBRARIES ${DCMTK_LIBRARIES}
+                     LINK_LIBRARIES DCMTK::DCMTK
                      DEFINITIONS "-DUSE_DCMTK=1")
 else ()
     message (WARNING "DICOM plugin will not be built, no DCMTK")