From e94969000a4498296833feda04f3ef21898bf281 Mon Sep 17 00:00:00 2001
From: Teon Banek <teon.banek@memgraph.io>
Date: Mon, 6 Mar 2017 16:15:20 +0100
Subject: [PATCH] Block in-source builds and add clean_all target

Summary:
Add detecting and blocking in-source builds

A simple cmake function, which detects if the source and build dir are
one and the same. This unfortunately does not catch the case when the
build dir is inside the source dir, since we actually want to support
that. For example, creating a 'build' directory inside the project
source directory should be allowed.

Add a clean_all custom target in cmake

This target will clean all the files inside the build directory. It
should be used with care!

A new cmake module is created, since invoking cmake -E remove_directory
will delete the directory and we want to keep it. This way, we also
avoid using platform specific shell command, i.e `rm -rf` and we can
make clean_all smarter in the future.

Untrack build/.gitignore from git

Reviewers: buda

Reviewed By: buda

Subscribers: pullbot

Differential Revision: https://phabricator.memgraph.io/D92
---
 .gitignore            |  2 +-
 CMakeLists.txt        |  7 +++++++
 build/.gitignore      |  2 --
 cmake/clean_all.cmake |  2 ++
 cmake/functions.cmake | 16 ++++++++++++++++
 init.sh               |  3 +++
 6 files changed, 29 insertions(+), 3 deletions(-)
 delete mode 100644 build/.gitignore
 create mode 100644 cmake/clean_all.cmake

diff --git a/.gitignore b/.gitignore
index c5d77708b..3a852fd9b 100644
--- a/.gitignore
+++ b/.gitignore
@@ -20,7 +20,7 @@ release/memgraph_*
 release/libs/
 release/barrier/
 release/barrier_*
-build/compiled/
+build/
 cmake-build-*
 .idea
 cmake/DownloadProject/
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 0de821407..6ec979ca4 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -40,6 +40,13 @@ set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} ${PROJECT_SOURCE_DIR}/cmake)
 include(functions)
 # -----------------------------------------------------------------------------
 
+# We want out of source builds, so that cmake generated files don't get mixed
+# with source files. This allows for easier clean up.
+disallow_in_source_build()
+add_custom_target(clean_all
+                  COMMAND ${CMAKE_COMMAND} -P ${PROJECT_SOURCE_DIR}/cmake/clean_all.cmake
+                  COMMENT "Removing all files in ${CMAKE_BINARY_DIR}")
+
 # threading
 find_package(Threads REQUIRED)
 # -----------------------------------------------------------------------------
diff --git a/build/.gitignore b/build/.gitignore
deleted file mode 100644
index 78d910160..000000000
--- a/build/.gitignore
+++ /dev/null
@@ -1,2 +0,0 @@
-/*
-!.gitignore
diff --git a/cmake/clean_all.cmake b/cmake/clean_all.cmake
new file mode 100644
index 000000000..13c932f80
--- /dev/null
+++ b/cmake/clean_all.cmake
@@ -0,0 +1,2 @@
+file(GLOB build_contents "${CMAKE_BINARY_DIR}/*")
+file(REMOVE_RECURSE ${build_contents})
diff --git a/cmake/functions.cmake b/cmake/functions.cmake
index 109db7944..ac2ab1834 100644
--- a/cmake/functions.cmake
+++ b/cmake/functions.cmake
@@ -27,3 +27,19 @@ MACRO(SUBDIRLIST result curdir)
     ENDFOREACH()
     SET(${result} ${dirlist})
 ENDMACRO()
+
+function(disallow_in_source_build)
+    get_filename_component(src_dir ${CMAKE_SOURCE_DIR} REALPATH)
+    get_filename_component(bin_dir ${CMAKE_BINARY_DIR} REALPATH)
+    message(STATUS "SOURCE_DIR" ${src_dir})
+    message(STATUS "BINARY_DIR" ${bin_dir})
+    # Do we maybe want to limit out-of-source builds to be only inside a
+    # directory which contains 'build' in name?
+    if("${src_dir}" STREQUAL "${bin_dir}")
+        # Unfortunately, we cannot remove CMakeCache.txt and CMakeFiles here
+        # because they are written after cmake is done.
+        message(FATAL_ERROR "In source build is not supported! "
+                "Remove CMakeCache.txt and CMakeFiles and then create a separate "
+                "directory, e.g. 'build' and run cmake there.")
+    endif()
+endfunction()
diff --git a/init.sh b/init.sh
index 8a3ac285f..e7d6f2626 100755
--- a/init.sh
+++ b/init.sh
@@ -5,6 +5,9 @@ for pkg in wget git cmake uuid-dev clang-3.8; do
     dpkg -s $pkg 2>/dev/null >/dev/null || sudo apt-get -y install $pkg
 done
 
+# create a default build directory
+mkdir -p ./build
+
 # setup libs (download)
 cd libs
 ./setup.sh