From 9e8e4574285cc52caaba1b5ad595fad3c4e89cb8 Mon Sep 17 00:00:00 2001
From: =?utf8?q?Peter=20K=C3=BCmmel?= <syntheticpp@gmx.net>
Date: Wed, 2 May 2007 20:47:47 +0000
Subject: [PATCH] cmake: don't rebuild merges files on each cmake run, force
 rebuild by -Dmerge_rebuild=1

git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@18175 a592a061-630c-0410-9148-cb99ea01b6c8
---
 development/cmake/modules/LyXMacros.cmake | 63 ++++++++++++++++++-----
 1 file changed, 50 insertions(+), 13 deletions(-)

diff --git a/development/cmake/modules/LyXMacros.cmake b/development/cmake/modules/LyXMacros.cmake
index 8af9eca67d..0749961f1c 100644
--- a/development/cmake/modules/LyXMacros.cmake
+++ b/development/cmake/modules/LyXMacros.cmake
@@ -131,13 +131,46 @@ macro(lyx_const_touched_files _allinone_name _list)
    set(_file_const ${CMAKE_CURRENT_BINARY_DIR}/${_allinone_name}_const.C)
    set(_file_touched ${CMAKE_CURRENT_BINARY_DIR}/${_allinone_name}_touched.C)
    
-   file(WRITE ${_file_const} "//autogenerated file\n")
-   file(WRITE ${_file_touched} "//autogenerated file\n")
    
-   file(APPEND ${_file_touched} "// touched files\n\n")
-   file(APPEND ${_file_touched} "// look for non-const files\n")
-   file(APPEND ${_file_touched} "#define DONT_INCLUDE_CONST_FILES\n")
-   file(APPEND ${_file_touched} "#include \"${_file_const}\"\n\n\n")
+   # don't touch exisiting or non-empty file,
+   # so a cmake re-run doesn't touch all created files
+   set(_rebuild_file_const 0)
+   if (NOT EXISTS ${_file_const})
+      set(_rebuild_file_const 1)
+   else (NOT EXISTS ${_file_const})
+      FILE(READ ${_file_const} _file_content)
+      if (NOT _file_content)
+         set(_rebuild_file_const 1)
+      endif (NOT _file_content)
+   endif (NOT EXISTS ${_file_const})
+   
+   set(_rebuild_file_touched 0)
+   if (NOT EXISTS ${_file_touched})
+      set(_rebuild_file_touched 1)
+   else (NOT EXISTS ${_file_touched})
+      FILE(READ ${_file_touched} _file_content)
+      if (NOT _file_content)
+         set(_rebuild_file_touched 1)
+      endif (NOT _file_content)   
+   endif (NOT EXISTS ${_file_touched})
+   
+   if (merge_rebuild)
+      set(_rebuild_file_const 1)
+      set(_rebuild_file_touched 1)
+   endif (merge_rebuild)
+   
+   if (_rebuild_file_const)
+      file(WRITE  ${_file_const} "// autogenerated file \n//\n")
+      file(APPEND ${_file_const} "//    * clear or delete this file to build it again by cmake \n//\n\n")
+   endif (_rebuild_file_const)
+
+   if (_rebuild_file_touched)
+      file(WRITE  ${_file_touched} "// autogenerated file \n//\n")
+      file(APPEND ${_file_touched} "//    * clear or delete this file to build it again by cmake \n//\n")
+      file(APPEND ${_file_touched} "//    * don't touch this file \n//\n\n")
+      file(APPEND ${_file_touched} "#define DONT_INCLUDE_CONST_FILES\n")
+      file(APPEND ${_file_touched} "#include \"${_file_const}\"\n\n\n")
+   endif (_rebuild_file_touched)
    
    set(${_file_list} ${_file_const} ${_file_touched})
    
@@ -153,14 +186,18 @@ macro(lyx_const_touched_files _allinone_name _list)
         STRING(REGEX REPLACE "-" "_" _file_name "${_file_name}" )
         set(__macro_name ${_file_name}___ASSUME_CONST)
         
-        file(APPEND ${_file_const}  "#define ${__macro_name}\n")
-        file(APPEND ${_file_const}  "#if defined(${__macro_name}) && !defined(DONT_INCLUDE_CONST_FILES)\n")
-        file(APPEND ${_file_const}  "#include \"${_abs_FILE}\"\n")
-        file(APPEND ${_file_const}  "#endif\n\n")
+        if (_rebuild_file_const)
+           file(APPEND ${_file_const}  "#define ${__macro_name}\n")
+           file(APPEND ${_file_const}  "#if defined(${__macro_name}) && !defined(DONT_INCLUDE_CONST_FILES)\n")
+           file(APPEND ${_file_const}  "#include \"${_abs_FILE}\"\n")
+           file(APPEND ${_file_const}  "#endif\n\n")
+        endif (_rebuild_file_const)
         
-        file(APPEND ${_file_touched}  "#ifndef ${__macro_name}\n")
-        file(APPEND ${_file_touched}  "#include \"${_abs_FILE}\"\n")
-        file(APPEND ${_file_touched}  "#endif\n\n")
+        if (_rebuild_file_touched)
+           file(APPEND ${_file_touched}  "#ifndef ${__macro_name}\n")
+           file(APPEND ${_file_touched}  "#include \"${_abs_FILE}\"\n")
+           file(APPEND ${_file_touched}  "#endif\n\n")
+        endif (_rebuild_file_touched)
       endif (_isGenerated)
    endforeach (_current_FILE)
 endmacro(lyx_const_touched_files)
-- 
2.39.5