From ca95ad9618076fb0f054544ac5eda9abf9049d7f Mon Sep 17 00:00:00 2001
From: Jon Siwek <jsiwek@ncsa.illinois.edu>
Date: Fri, 29 Jul 2011 17:29:17 -0500
Subject: [PATCH] Install example config files dynamically.

They'll only get installed when the distribution version differs
from existing version on disk.
---
 cmake/InstallClobberImmune.cmake     |  6 ++++++
 cmake/InstallPackageConfigFile.cmake | 13 ++++++++-----
 cmake/package_postupgrade.sh.in      |  3 ++-
 3 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/cmake/InstallClobberImmune.cmake b/cmake/InstallClobberImmune.cmake
index 77da312ef2..f3da8b88bb 100644
--- a/cmake/InstallClobberImmune.cmake
+++ b/cmake/InstallClobberImmune.cmake
@@ -9,6 +9,12 @@ macro(InstallClobberImmune _srcfile _dstfile)
     install(CODE "
         if (EXISTS ${_dstfile})
             message(STATUS \"Skipping: ${_dstfile} (already exists)\")
+            execute_process(COMMAND \"${CMAKE_COMMAND}\" -E compare_files
+                ${_srcfile} ${_dstfile} RESULT_VARIABLE _diff)
+            if (NOT \"\${_diff}\" STREQUAL \"0\")
+                message(STATUS \"Installing: ${_dstfile}.example\")
+                configure_file(${_srcfile} ${_dstfile}.example COPY_ONLY)
+            endif ()
         else ()
             message(STATUS \"Installing: ${_dstfile}\")
             # install() is not scriptable within install(), and
diff --git a/cmake/InstallPackageConfigFile.cmake b/cmake/InstallPackageConfigFile.cmake
index 65a1724ea4..5850bb3783 100644
--- a/cmake/InstallPackageConfigFile.cmake
+++ b/cmake/InstallPackageConfigFile.cmake
@@ -3,7 +3,6 @@ include(InstallClobberImmune)
 # This macro can be used to install configuration files which
 # users are expected to modify after installation.  It will:
 #
-#   - Always install one version of the file with a .example suffix
 #   - If binary packaging is enabled:
 #     Install the file in the typical CMake fashion, but append to the
 #     INSTALLED_CONFIG_FILES cache variable for use with the Mac package's
@@ -19,10 +18,6 @@ include(InstallClobberImmune)
 macro(InstallPackageConfigFile _srcfile _dstdir _dstfilename)
     set(_dstfile ${_dstdir}/${_dstfilename})
 
-    # Always install the latest version of the file renamed as an example
-    install(FILES ${_srcfile} DESTINATION ${_dstdir}
-            RENAME ${_dstfilename}.example)
-
     if (BINARY_PACKAGING_MODE)
         # If packaging mode is enabled, always install the distribution's
         # version of the file.  The Mac package's pre/post install scripts
@@ -32,6 +27,14 @@ macro(InstallPackageConfigFile _srcfile _dstdir _dstfilename)
         # use to avoid clobbering user-modified config files
         set(INSTALLED_CONFIG_FILES
             "${INSTALLED_CONFIG_FILES} ${_dstfile}" CACHE STRING "" FORCE)
+
+        # Additionally, the Mac PackageMaker packages don't have any automatic
+        # handling of configuration file conflicts so install an example file
+        # that the post install script will cleanup in the case it's extraneous
+        if (APPLE)
+            install(FILES ${_srcfile} DESTINATION ${_dstdir}
+                    RENAME ${_dstfilename}.example)
+        endif ()
     else ()
         # Have `make install` check at run time whether the file does not exist
         InstallClobberImmune(${_srcfile} ${_dstfile})
diff --git a/cmake/package_postupgrade.sh.in b/cmake/package_postupgrade.sh.in
index 4e199d005c..7d40950fc1 100755
--- a/cmake/package_postupgrade.sh.in
+++ b/cmake/package_postupgrade.sh.in
@@ -20,8 +20,9 @@ if [ -e ${backupNamesFile} ]; then
 
         if [ $? -eq 0 ]; then
             # if the installed version and the backup version don't differ
-            # then we can remove the backup version
+            # then we can remove the backup version and the example file
             rm ${backupFile}
+            rm ${origFileName}.example
         else
             # The backup file differs from the newly installed version,
             # since we can't tell if the backup version has been modified