Ensure Out of Source builds

In source builds creates a lot of noise on the source tree,
creating tons of temporaries that makes git status cry, and it also
creates dangerous files that have names similar to actual source
and could make a developer use them by mistake.

Make out of source buiild mandatory to remove that, it also makes
CMake code easier to read.

Signed-off-by: Tomaz Canabrava <tomaz.canabrava@intel.com>

2 files changed, 38 insertions, 13 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index cb174b1fc..c9c429608 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -3,10 +3,13 @@
 project(Subsurface)
 cmake_minimum_required(VERSION 2.8.11)
 
-
 # global settings
 
 set(CMAKE_AUTOMOC ON)
+include(cmake/Modules/MacroOutOfSourceBuild.cmake)
+MACRO_ENSURE_OUT_OF_SOURCE_BUILD(
+    "We don't support building in source, please create a build folder elsewhere and remember to run git clean -xdf to remoev temporary files created by CMake."
+)
 
 option(LIBGIT2_FROM_PKGCONFIG "use pkg-config to retrieve libgit2" OFF)
 option(LIBDC_FROM_PKGCONFIG "use pkg-config to retrieve libdivecomputer" OFF)
@@ -153,18 +156,7 @@ endif()
 
 set(SUBSURFACE_LINK_LIBRARIES ${SUBSURFACE_LINK_LIBRARIES} ${LIBDIVECOMPUTER_LIBRARIES} ${LIBGIT2_LIBRARIES} ${LIBUSB_LIBRARIES})
 
-# handle out of tree build correctly
-string(COMPARE EQUAL "${${PROJECT_NAME}_SOURCE_DIR}" "${${PROJECT_NAME}_BINARY_DIR}" insource)
-if (insource)
-	message(STATUS "building in Subsurface source tree - we recommend out of tree builds")
-else()
-	message(STATUS "out of source build from source in ${${PROJECT_NAME}_SOURCE_DIR}")
-endif()
-get_filename_component(PARENTDIR ${${PROJECT_NAME}_SOURCE_DIR} PATH)
-string(COMPARE EQUAL "${${PROJECT_NAME}_SOURCE_DIR}" "${PARENTDIR}" insourcesubdir)
-if(NOT (insource OR insourcedir))
-	add_custom_target(link_marble_data ALL COMMAND rm -rf ./marbledata && ln -s ${CMAKE_SOURCE_DIR}/marbledata ${CMAKE_BINARY_DIR}/marbledata)
-endif()
+add_custom_target(link_marble_data ALL COMMAND rm -rf ./marbledata && ln -s ${CMAKE_SOURCE_DIR}/marbledata ${CMAKE_BINARY_DIR}/marbledata)
 
 # configure Qt.
 if(SUBSURFACE_MOBILE)
diff --git a/cmake/Modules/MacroOutOfSourceBuild.cmake b/cmake/Modules/MacroOutOfSourceBuild.cmake
new file mode 100644
index 000000000..dedeef352
--- /dev/null
+++ b/cmake/Modules/MacroOutOfSourceBuild.cmake
@@ -0,0 +1,33 @@
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+# 
+# 1. Redistributions of source code must retain the copyright
+#    notice, this list of conditions and the following disclaimer.
+# 2. Redistributions in binary form must reproduce the copyright
+#    notice, this list of conditions and the following disclaimer in the
+#    documentation and/or other materials provided with the distribution.
+# 3. The name of the author may not be used to endorse or promote products
+#    derived from this software without specific prior written permission.
+# 
+# THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+# IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+# OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+# IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+# NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+# # Ensures that we do an out of source build
+MACRO(MACRO_ENSURE_OUT_OF_SOURCE_BUILD MSG)
+    STRING(COMPARE EQUAL "${CMAKE_SOURCE_DIR}" "${CMAKE_BINARY_DIR}" insource)
+    GET_FILENAME_COMPONENT(PARENTDIR ${CMAKE_SOURCE_DIR} PATH)
+    STRING(COMPARE EQUAL "${CMAKE_SOURCE_DIR}" "${PARENTDIR}" insourcesubdir)
+    MESSAGE( "${CMAKE_SOURCE_DIR} , ${CMAKE_BINARY_DIR}, ${PARENTDIR}")
+    IF(insource OR insourcesubdir)
+        MESSAGE(FATAL_ERROR "${MSG}")
+    ENDIF(insource OR insourcesubdir)
+ENDMACRO(MACRO_ENSURE_OUT_OF_SOURCE_BUILD)
\ No newline at end of file