major improvement of FindRuby.cmake

-now supports specifying minimum required version
-now supports ruby 1.8 and 1.9
-uses find_package_handle_standard_args() now
-fix #6212 and using a lot of ideas from the file attached there

Alex

Modules/FindRuby.cmake

@@ -1,11 +1,16 @@
 # - Find Ruby
 # This module finds if Ruby is installed and determines where the include files
-# and libraries are. It also determines what the name of the library is. This
+# and libraries are. Ruby 1.8 and 1.9 are supported. The minimum required version 
+# specified in the find_package() command is honored.
+# It also determines what the name of the library is. This
 # code sets the following variables:
 #
-#  RUBY_INCLUDE_PATH = path to where ruby.h can be found
 #  RUBY_EXECUTABLE   = full path to the ruby binary
+#  RUBY_INCLUDE_DIRS = include dirs to be used when using the ruby library
 #  RUBY_LIBRARY      = full path to the ruby library
+#  RUBY_FOUND        = set to true if ruby ws found successfully
+#
+#  RUBY_INCLUDE_PATH = same as RUBY_INCLUDE_DIRS, only provided for compatibility reasons, don't use it
 
 # Copyright (c) 2002 Kitware, Inc., Insight Consortium.  All rights reserved.
 # See Copyright.txt or http://www.cmake.org/HTML/Copyright.html for details.
@@ -17,13 +22,51 @@
 #   RUBY_LIBDIR=`$RUBY -r rbconfig -e 'printf("%s",Config::CONFIG@<:@"libdir"@:>@)'`
 #   RUBY_LIBRUBYARG=`$RUBY -r rbconfig -e 'printf("%s",Config::CONFIG@<:@"LIBRUBYARG_SHARED"@:>@)'`
 
-FIND_PROGRAM(RUBY_EXECUTABLE NAMES ruby ruby1.8 ruby18 ruby1.9 ruby19)
+# uncomment the following line to get debug output for this file
+# SET(_RUBY_DEBUG_OUTPUT TRUE)
+
+# Determine the list of possible names of the ruby executable depending
+# on which version of ruby is required
+SET(_RUBY_POSSIBLE_EXECUTABLE_NAMES ruby)
+
+# if 1.9 is required, don't look for ruby18 and ruby1.8, default to version 1.8
+IF(Ruby_FIND_VERSION_MAJOR  AND  Ruby_FIND_VERSION_MINOR)
+   SET(Ruby_FIND_VERSION_SHORT_NODOT "${Ruby_FIND_VERSION_MAJOR}${RUBY_FIND_VERSION_MINOR}")
+ELSE(Ruby_FIND_VERSION_MAJOR  AND  Ruby_FIND_VERSION_MINOR)
+   SET(Ruby_FIND_VERSION_SHORT_NODOT "18")
+ENDIF(Ruby_FIND_VERSION_MAJOR  AND  Ruby_FIND_VERSION_MINOR)
+
+SET(_RUBY_POSSIBLE_EXECUTABLE_NAMES ${_RUBY_POSSIBLE_EXECUTABLE_NAMES} ruby1.9 ruby19)
+
+# if we want a version below 1.9, also look for ruby 1.8
+IF("${Ruby_FIND_VERSION_SHORT_NODOT}" VERSION_LESS "19")
+   SET(_RUBY_POSSIBLE_EXECUTABLE_NAMES ${_RUBY_POSSIBLE_EXECUTABLE_NAMES} ruby1.8 ruby18)
+ENDIF("${Ruby_FIND_VERSION_SHORT_NODOT}" VERSION_LESS "19")
 
+FIND_PROGRAM(RUBY_EXECUTABLE NAMES ${_RUBY_POSSIBLE_EXECUTABLE_NAMES})
 
-IF(RUBY_EXECUTABLE  AND NOT  RUBY_ARCH_DIR)
+
+IF(RUBY_EXECUTABLE  AND NOT  RUBY_MAJOR_VERSION)
+  # query the ruby version
+   EXECUTE_PROCESS(COMMAND ${RUBY_EXECUTABLE} -r rbconfig -e "print Config::CONFIG['MAJOR']"
+      OUTPUT_VARIABLE RUBY_VERSION_MAJOR)
+
+   EXECUTE_PROCESS(COMMAND ${RUBY_EXECUTABLE} -r rbconfig -e "print Config::CONFIG['MINOR']"
+      OUTPUT_VARIABLE RUBY_VERSION_MINOR)
+
+   EXECUTE_PROCESS(COMMAND ${RUBY_EXECUTABLE} -r rbconfig -e "print Config::CONFIG['TEENY']"
+      OUTPUT_VARIABLE RUBY_VERSION_PATCH)
+
+   # query the different directories
    EXECUTE_PROCESS(COMMAND ${RUBY_EXECUTABLE} -r rbconfig -e "print Config::CONFIG['archdir']"
       OUTPUT_VARIABLE RUBY_ARCH_DIR)
 
+   EXECUTE_PROCESS(COMMAND ${RUBY_EXECUTABLE} -r rbconfig -e "print Config::CONFIG['arch']"
+      OUTPUT_VARIABLE RUBY_ARCH)
+
+   EXECUTE_PROCESS(COMMAND ${RUBY_EXECUTABLE} -r rbconfig -e "print Config::CONFIG['rubyhdrdir']"
+      OUTPUT_VARIABLE RUBY_HDR_DIR)
+
    EXECUTE_PROCESS(COMMAND ${RUBY_EXECUTABLE} -r rbconfig -e "print Config::CONFIG['libdir']"
       OUTPUT_VARIABLE RUBY_POSSIBLE_LIB_DIR)
 
@@ -50,45 +93,152 @@ IF(RUBY_EXECUTABLE  AND NOT  RUBY_ARCH_DIR)
    ENDIF(RUBY_HAS_VENDOR_RUBY)
 
    # save the results in the cache so we don't have to run ruby the next time again
-   SET(RUBY_ARCH_DIR         ${RUBY_ARCH_DIR}         CACHE PATH "The Ruby arch dir")
-   SET(RUBY_POSSIBLE_LIB_DIR ${RUBY_POSSIBLE_LIB_DIR} CACHE PATH "The Ruby lib dir")
-   SET(RUBY_RUBY_LIB_DIR     ${RUBY_RUBY_LIB_DIR}     CACHE PATH "The Ruby ruby-lib dir")
-   SET(RUBY_SITEARCH_DIR     ${RUBY_SITEARCH_DIR}     CACHE PATH "The Ruby site arch dir")
-   SET(RUBY_SITELIB_DIR      ${RUBY_SITELIB_DIR}      CACHE PATH "The Ruby site lib dir")
-   SET(RUBY_HAS_VENDOR_RUBY  ${RUBY_HAS_VENDOR_RUBY}  CACHE BOOL "Vendor Ruby is available")
-   SET(RUBY_VENDORARCH_DIR   ${RUBY_VENDORARCH_DIR}   CACHE PATH "The Ruby vendor arch dir")
-   SET(RUBY_VENDORLIB_DIR    ${RUBY_VENDORLIB_DIR}    CACHE PATH "The Ruby vendor lib dir")
-
-ENDIF(RUBY_EXECUTABLE  AND NOT  RUBY_ARCH_DIR)
-
-# for compatibility
-SET(RUBY_POSSIBLE_LIB_PATH ${RUBY_POSSIBLE_LIB_DIR})
-SET(RUBY_RUBY_LIB_PATH ${RUBY_RUBY_LIB_DIR})
-
-
-FIND_PATH(RUBY_INCLUDE_PATH
+   SET(RUBY_VERSION_MAJOR    ${RUBY_VERSION_MAJOR}    CACHE PATH "The Ruby major version" FORCE)
+   SET(RUBY_VERSION_MINOR    ${RUBY_VERSION_MINOR}    CACHE PATH "The Ruby minor version" FORCE)
+   SET(RUBY_VERSION_PATCH    ${RUBY_VERSION_PATCH}    CACHE PATH "The Ruby patch version" FORCE)
+   SET(RUBY_ARCH_DIR         ${RUBY_ARCH_DIR}         CACHE PATH "The Ruby arch dir" FORCE)
+   SET(RUBY_HDR_DIR          ${RUBY_HDR_DIR}          CACHE PATH "The Ruby header dir (1.9)" FORCE)
+   SET(RUBY_POSSIBLE_LIB_DIR ${RUBY_POSSIBLE_LIB_DIR} CACHE PATH "The Ruby lib dir" FORCE)
+   SET(RUBY_RUBY_LIB_DIR     ${RUBY_RUBY_LIB_DIR}     CACHE PATH "The Ruby ruby-lib dir" FORCE)
+   SET(RUBY_SITEARCH_DIR     ${RUBY_SITEARCH_DIR}     CACHE PATH "The Ruby site arch dir" FORCE)
+   SET(RUBY_SITELIB_DIR      ${RUBY_SITELIB_DIR}      CACHE PATH "The Ruby site lib dir" FORCE)
+   SET(RUBY_HAS_VENDOR_RUBY  ${RUBY_HAS_VENDOR_RUBY}  CACHE BOOL "Vendor Ruby is available" FORCE)
+   SET(RUBY_VENDORARCH_DIR   ${RUBY_VENDORARCH_DIR}   CACHE PATH "The Ruby vendor arch dir" FORCE)
+   SET(RUBY_VENDORLIB_DIR    ${RUBY_VENDORLIB_DIR}    CACHE PATH "The Ruby vendor lib dir" FORCE)
+
+   MARK_AS_ADVANCED(
+     RUBY_ARCH_DIR
+     RUBY_ARCH
+     RUBY_HDR_DIR
+     RUBY_POSSIBLE_LIB_DIR
+     RUBY_RUBY_LIB_DIR
+     RUBY_SITEARCH_DIR
+     RUBY_SITELIB_DIR
+     RUBY_HAS_VENDOR_RUBY
+     RUBY_VENDORARCH_DIR
+     RUBY_VENDORLIB_DIR
+     RUBY_VERSION_MAJOR
+     RUBY_VERSION_MINOR
+     RUBY_VERSION_PATCH
+     )
+ENDIF(RUBY_EXECUTABLE  AND NOT  RUBY_MAJOR_VERSION)
+
+# In case RUBY_EXECUTABLE could not be executed (e.g. cross compiling) 
+# try to detect which version we found. This is not too good.
+IF(NOT RUBY_VERSION_MAJOR)
+   # by default assume 1.8.0
+   SET(RUBY_VERSION_MAJOR 1)
+   SET(RUBY_VERSION_MINOR 8)
+   SET(RUBY_VERSION_PATCH 0)
+   # check whether we found 1.9.x
+   IF(${RUBY_EXECUTABLE} MATCHES "ruby1.?9"  OR  RUBY_HDR_DIR)
+      SET(RUBY_VERSION_MAJOR 1)
+      SET(RUBY_VERSION_MINOR 9)
+   ENDIF(${RUBY_EXECUTABLE} MATCHES "ruby1.?9"  OR  RUBY_HDR_DIR)
+ENDIF(NOT RUBY_VERSION_MAJOR)
+
+
+SET(RUBY_VERSION "${RUBY_VERSION_MAJOR}.${RUBY_VERSION_MINOR}.${RUBY_VERSION_PATCH}")
+SET(_RUBY_VERSION_SHORT "${RUBY_VERSION_MAJOR}.${RUBY_VERSION_MINOR}")
+SET(_RUBY_VERSION_SHORT_NODOT "${RUBY_VERSION_MAJOR}${RUBY_VERSION_MINOR}")
+
+# Now we know which version we found
+IF(Ruby_FIND_VERSION)
+   IF(${RUBY_VERSION}  VERSION_LESS  ${Ruby_FIND_VERSION})
+      # force running ruby the next time again
+      SET(RUBY_VERSION_MAJOR    ""    CACHE PATH "The Ruby major version" FORCE)
+      IF(Ruby_FIND_REQUIRED)
+         MESSAGE(FATAL_ERROR "Ruby version ${Ruby_FIND_VERSION} required, but only version ${RUBY_VERSION} found.")
+      ELSE(Ruby_FIND_REQUIRED)
+         IF(NOT Ruby_FIND_QUIETLY)
+            MESSAGE(STATUS "Ruby version ${Ruby_FIND_VERSION} required, but only version ${RUBY_VERSION} found.")
+         ENDIF(NOT Ruby_FIND_QUIETLY)
+         RETURN()
+      ENDIF(Ruby_FIND_REQUIRED)
+   ENDIF(${RUBY_VERSION}  VERSION_LESS  ${Ruby_FIND_VERSION})
+ENDIF(Ruby_FIND_VERSION)
+
+FIND_PATH(RUBY_INCLUDE_DIR
    NAMES ruby.h
    HINTS
+   ${RUBY_HDR_DIR}
    ${RUBY_ARCH_DIR}
-  /usr/lib/ruby/1.8/i586-linux-gnu/ )
-
-# search the ruby library, the version for MSVC can have the "msvc" prefix and the "static" suffix
-FIND_LIBRARY(RUBY_LIBRARY
-  NAMES ruby ruby-static ruby1.8 ruby1.9
-        msvcrt-ruby18 msvcrt-ruby19 msvcrt-ruby18-static msvcrt-ruby19-static
-  HINTS ${RUBY_POSSIBLE_LIB_DIR}
-  )
+   /usr/lib/ruby/${_RUBY_VERSION_SHORT}/i586-linux-gnu/ )
+
+SET(RUBY_INCLUDE_DIRS ${RUBY_INCLUDE_DIR} )
+
+# if ruby > 1.8 is required or if ruby > 1.8 was found, search for the config.h dir
+IF( ${Ruby_FIND_VERSION_SHORT_NODOT} GREATER 18  OR  ${_RUBY_VERSION_SHORT_NODOT} GREATER 18  OR  RUBY_HDR_DIR)
+   message(STATUS "lookign for config.h")
+   FIND_PATH(RUBY_CONFIG_INCLUDE_DIR
+     NAMES ruby/config.h  config.h
+     HINTS 
+     ${RUBY_HDR_DIR}/${RUBY_ARCH}
+     ${RUBY_ARCH_DIR} 
+     )
+
+   SET(RUBY_INCLUDE_DIRS ${RUBY_INCLUDE_DIRS} ${RUBY_CONFIG_INCLUDE_DIR} )
+ENDIF( ${Ruby_FIND_VERSION_SHORT_NODOT} GREATER 18  OR  ${_RUBY_VERSION_SHORT_NODOT} GREATER 18  OR  RUBY_HDR_DIR)
+
+
+# Determine the list of possible names for the ruby library
+SET(_RUBY_POSSIBLE_LIB_NAMES ruby ruby-static ruby${_RUBY_VERSION_SHORT})
+
+IF(WIN32)
+   SET( _RUBY_MSVC_RUNTIME "" )
+   IF( MSVC60 )
+     SET( _RUBY_MSVC_RUNTIME "60" )
+   ENDIF( MSVC60 )
+   IF( MSVC70 )
+     SET( _RUBY_MSVC_RUNTIME "70" )
+   ENDIF( MSVC70 )
+   IF( MSVC71 )
+     SET( _RUBY_MSVC_RUNTIME "71" )
+   ENDIF( MSVC71 )
+   IF( MSVC80 )
+     SET( _RUBY_MSVC_RUNTIME "80" )
+   ENDIF( MSVC80 )
+   IF( MSVC90 )
+     SET( _RUBY_MSVC_RUNTIME "90" )
+   ENDIF( MSVC90 )
+
+   LIST(APPEND _RUBY_POSSIBLE_LIB_NAMES
+               "msvcr${_RUBY_MSVC_RUNTIME}-ruby${RUBY_NODOT_VERSION}"
+               "msvcr${_RUBY_MSVC_RUNTIME}-ruby${RUBY_NODOT_VERSION}-static" 
+               "msvcrt-ruby${RUBY_NODOT_VERSION}"
+               "msvcrt-ruby${RUBY_NODOT_VERSION}-static" )
+ENDIF(WIN32)
+
+FIND_LIBRARY(RUBY_LIBRARY NAMES ${_RUBY_POSSIBLE_LIB_NAMES} HINTS ${RUBY_POSSIBLE_LIB_DIR} )
+
+INCLUDE(FindPackageHandleStandardArgs)
+SET(_RUBY_REQUIRED_VARS RUBY_EXECUTABLE RUBY_INCLUDE_DIR RUBY_LIBRARY)
+IF(_RUBY_VERSION_SHORT_NODOT GREATER 18)
+   LIST(APPEND _RUBY_REQUIRED_VARS RUBY_CONFIG_INCLUDE_DIR)
+ENDIF(_RUBY_VERSION_SHORT_NODOT GREATER 18)
+
+IF(_RUBY_DEBUG_OUTPUT)
+   MESSAGE(STATUS "--------FindRuby.cmake debug------------")
+   MESSAGE(STATUS "_RUBY_POSSIBLE_EXECUTABLE_NAMES: ${_RUBY_POSSIBLE_EXECUTABLE_NAMES}")
+   MESSAGE(STATUS "_RUBY_POSSIBLE_LIB_NAMES: ${_RUBY_POSSIBLE_LIB_NAMES}")
+   MESSAGE(STATUS "RUBY_ARCH_DIR: ${RUBY_ARCH_DIR}")
+   MESSAGE(STATUS "RUBY_HDR_DIR: ${RUBY_HDR_DIR}")
+   MESSAGE(STATUS "RUBY_POSSIBLE_LIB_DIR: ${RUBY_POSSIBLE_LIB_DIR}")
+   MESSAGE(STATUS "Found RUBY_VERSION: \"${RUBY_VERSION}\" , short: \"${_RUBY_VERSION_SHORT}\", nodot: \"${_RUBY_VERSION_SHORT_NODOT}\"")
+   MESSAGE(STATUS "_RUBY_REQUIRED_VARS: ${_RUBY_REQUIRED_VARS}")
+   MESSAGE(STATUS "--------------------")
+ENDIF(_RUBY_DEBUG_OUTPUT)
+
+FIND_PACKAGE_HANDLE_STANDARD_ARGS(Ruby  DEFAULT_MSG  ${_RUBY_REQUIRED_VARS})
 
 MARK_AS_ADVANCED(
   RUBY_EXECUTABLE
   RUBY_LIBRARY
-  RUBY_INCLUDE_PATH
-  RUBY_ARCH_DIR
-  RUBY_POSSIBLE_LIB_DIR
-  RUBY_RUBY_LIB_DIR
-  RUBY_SITEARCH_DIR
-  RUBY_SITELIB_DIR
-  RUBY_HAS_VENDOR_RUBY
-  RUBY_VENDORARCH_DIR
-  RUBY_VENDORLIB_DIR
+  RUBY_INCLUDE_DIR
+  RUBY_CONFIG_INCLUDE_DIR
   )
+
+# Set some variables for compatibility with previous version of this file
+SET(RUBY_POSSIBLE_LIB_PATH ${RUBY_POSSIBLE_LIB_DIR})
+SET(RUBY_RUBY_LIB_PATH ${RUBY_RUBY_LIB_DIR})
+SET(RUBY_INCLUDE_PATH ${RUBY_INCLUDE_DIRS})