build: Remove Findfmt.cmake (AcademySoftwareFoundation#4069)

fmt provides cmake config files since at least version 7.0.0, which is
the minimum version supported.
Fixed some variable names, so the provided config can be used.
The previous variable names were missing, if the library was installed
in a custom location,
like in case of manual build or provided by conan.

---------

Signed-off-by: Dominik Wójt <[email protected]>
Signed-off-by: Peter Kovář <[email protected]>

Author: domin144

src/cmake/externalpackages.cmake

@@ -338,7 +338,7 @@ macro (find_or_download_fmt)
     # If an external copy wasn't found and we requested that missing
     # packages be built, or we we are forcing a local copy to be built, then
     # download and build it.
-    if ((BUILD_MISSING_FMT AND NOT FMT_FOUND) OR BUILD_FMT_FORCE)
+    if ((BUILD_MISSING_FMT AND NOT fmt_FOUND) OR BUILD_FMT_FORCE)
         message (STATUS "Downloading local fmtlib/fmt")
         set (FMT_INSTALL_DIR "${PROJECT_SOURCE_DIR}/ext/fmt")
         set (FMT_GIT_REPOSITORY "https://github.com/fmtlib/fmt")
@@ -356,16 +356,23 @@ macro (find_or_download_fmt)
         endif ()
         set (FMT_INCLUDE_DIR "${FMT_INSTALL_DIR}/include")
         set (OIIO_USING_FMT_LOCAL TRUE)
+        file (STRINGS "${FMT_INCLUDE_DIR}/fmt/core.h" TMP REGEX "^#define FMT_VERSION .*$")
+        string (REGEX MATCHALL "[0-9]+" FMT_VERSION_NUMERIC ${TMP})
+        math(EXPR FMT_VERSION_PATCH "${FMT_VERSION_NUMERIC} % 100")
+        math(EXPR FMT_VERSION_MINOR "(${FMT_VERSION_NUMERIC} / 100) % 100")
+        math(EXPR FMT_VERSION_MAJOR "${FMT_VERSION_NUMERIC} / 10000")
+        set (fmt_VERSION "${FMT_VERSION_MAJOR}.${FMT_VERSION_MINOR}.${FMT_VERSION_PATCH}")
     else ()
+        get_target_property(FMT_INCLUDE_DIR fmt::fmt-header-only INTERFACE_INCLUDE_DIRECTORIES)
         set (OIIO_USING_FMT_LOCAL FALSE)
+        checked_find_package (fmt REQUIRED
+                              VERSION_MIN 7.0)
     endif ()
-    checked_find_package (fmt REQUIRED
-                          VERSION_MIN 7.0)
 endmacro()
 
 find_or_download_fmt()
 
-if (FMT_VERSION VERSION_EQUAL 90100
+if (fmt_VERSION VERSION_EQUAL 9.1.0
         AND GCC_VERSION VERSION_GREATER 0.0 AND NOT GCC_VERSION VERSION_GREATER 7.2)
     message (WARNING "${ColorRed}fmt 9.1 is known to not work with gcc <= 7.2${ColorReset}")
 endif ()

src/cmake/modules/Findfmt.cmake

@@ -65,17 +65,28 @@ install (FILES ${detail_headers}
          COMPONENT developer)
 
 if (INTERNALIZE_FMT OR OIIO_USING_FMT_LOCAL)
-    set (fmt_headers
-         ${FMT_INCLUDES}/fmt/core.h
-         ${FMT_INCLUDES}/fmt/format-inl.h
-         ${FMT_INCLUDES}/fmt/format.h
-         ${FMT_INCLUDES}/fmt/ostream.h
-         ${FMT_INCLUDES}/fmt/printf.h )
-    if (fmt_VERSION VERSION_GREATER_EQUAL 90000)
-        list (APPEND fmt_headers ${FMT_INCLUDES}/fmt/std.h)
+    set (fmt_headers_base_names core.h format-inl.h format.h ostream.h printf.h)
+    if (fmt_VERSION VERSION_GREATER_EQUAL 9)
+        list (APPEND fmt_headers_base_names std.h)
     endif ()
-    file (COPY ${fmt_headers}
-          DESTINATION ${CMAKE_BINARY_DIR}/include/OpenImageIO/detail/fmt)
+    set (fmt_internal_directory ${CMAKE_BINARY_DIR}/include/OpenImageIO/detail/fmt)
+    list (TRANSFORM fmt_headers_base_names
+          PREPEND ${FMT_INCLUDE_DIR}/fmt/
+          OUTPUT_VARIABLE fmt_headers)
+    list (TRANSFORM fmt_headers_base_names
+          PREPEND ${fmt_internal_directory}/
+          OUTPUT_VARIABLE fmt_headers_internal)
+    add_custom_command (OUTPUT ${fmt_internal_directory}
+                        COMMAND
+                            ${CMAKE_COMMAND} -E make_directory
+                            ${fmt_internal_directory})
+    add_custom_command (OUTPUT ${fmt_headers_internal}
+                        DEPENDS ${fmt_headers} ${fmt_internal_directory}
+                        COMMAND
+                            ${CMAKE_COMMAND} -E copy
+                            ${fmt_headers}
+                            ${fmt_internal_directory})
+    add_custom_target (fmt_internal_target DEPENDS ${fmt_headers_internal})
 else ()
     set (fmt_headers
          ${CMAKE_BINARY_DIR}/include/OpenImageIO/detail/fmt/format.h
@@ -85,7 +96,7 @@ else ()
         file (WRITE "${CMAKE_BINARY_DIR}/include/OpenImageIO/detail/fmt/${f}"
                     "#include <fmt/${f}>")
     endforeach ()
-    if (fmt_VERSION VERSION_GREATER_EQUAL 90000)
+    if (fmt_VERSION VERSION_GREATER_EQUAL 9)
         list (APPEND fmt_headers ${CMAKE_BINARY_DIR}/include/OpenImageIO/detail/fmt/std.h)
         file (WRITE "${CMAKE_BINARY_DIR}/include/OpenImageIO/detail/fmt/std.h"
                     "#include <fmt/std.h>")

src/include/CMakeLists.txt

@@ -169,7 +169,12 @@ if (MINGW)
     target_link_libraries (OpenImageIO PRIVATE ws2_32)
 endif()
 
-
+if (INTERNALIZE_FMT OR OIIO_USING_FMT_LOCAL)
+    add_dependencies(OpenImageIO_Util fmt_internal_target)
+else ()
+    target_link_libraries (OpenImageIO_Util
+                           PUBLIC fmt::fmt-header-only)
+endif ()
 
 file (GLOB iba_sources "imagebufalgo_*.cpp")
 if (MSVC)

src/libOpenImageIO/CMakeLists.txt

@@ -27,11 +27,11 @@ target_link_libraries (OpenImageIO_Util
             ${CMAKE_DL_LIBS}
         )
 
-if (NOT OIIO_USING_FMT_LOCAL)
-    target_include_directories (OpenImageIO_Util
-                                PUBLIC ${FMT_INCLUDES} )
+if (INTERNALIZE_FMT OR OIIO_USING_FMT_LOCAL)
+    add_dependencies(OpenImageIO_Util fmt_internal_target)
+else ()
     target_link_libraries (OpenImageIO_Util
-                           PUBLIC $<TARGET_NAME_IF_EXISTS:fmt::fmt> )
+                           PUBLIC fmt::fmt-header-only)
 endif ()
 
 if (WIN32)