Always use latest build2 version (Ericsson#655)

* feat: add script to install latest build2 version

* ci: always use latest build2 in gitlab CI

* docs: update build2 install instructions

.gitlab/build-deps.sh

@@ -138,8 +138,7 @@ if [ ! -f $DEPS_INSTALL_RUNTIME_DIR/odb-install/bin/odb ]; then
   if [[ $ODB_VERSION == "2.5.0" ]]; then
     # build2
     cd $PACKAGES_DIR
-    wget --no-verbose --no-clobber https://download.build2.org/0.16.0/build2-install-0.16.0.sh
-    sh build2-install-0.16.0.sh --yes --trust yes --jobs $(nproc) $PACKAGES_DIR/build2-install
+    sh $CI_PROJECT_DIR/scripts/install_latest_build2.sh $PACKAGES_DIR/build2-install
     export PATH=$PACKAGES_DIR/build2-install/bin:$PATH
 
     # odb, libodb
@@ -160,9 +159,6 @@ if [ ! -f $DEPS_INSTALL_RUNTIME_DIR/odb-install/bin/odb ]; then
     bpkg build libodb-sqlite --yes --quiet --jobs $(nproc)
     bpkg build libodb-pgsql --yes --quiet --jobs $(nproc)
     bpkg install --all --recursive --quiet --jobs $(nproc)
-
-    rm -f $PACKAGES_DIR/build2-toolchain-0.16.0.tar.xz
-    rm -f $PACKAGES_DIR/build2-install-0.16.0.sh
   elif [[ $ODB_VERSION == "2.4.0" ]]; then
     # odb
     cd $PACKAGES_DIR

doc/deps.md

@@ -120,8 +120,8 @@ The ODB installation uses the build2 build system. (Build2 is not needed for
 CodeCompass so you may delete it right after the installation of ODB.)
 
 ```bash
-wget https://download.build2.org/0.16.0/build2-install-0.16.0.sh
-sh build2-install-0.16.0.sh --yes --trust yes "<build2_install_dir>"
+wget https://github.com/Ericsson/CodeCompass/blob/master/scripts/install_latest_build2.sh
+sh install_latest_build2.sh "<build2_install_dir>"
 ```
 
 Now, utilizing the *Build2* toolchain, we can build the *ODB* compiler and

scripts/install_latest_build2.sh

@@ -0,0 +1,44 @@
+#!/bin/bash
+
+if [ $# -lt 1 ]; then
+    echo "No installation directory was provided for build2!" 1>&2
+    exit 1
+fi
+
+## download phase
+
+install_dir=$1
+toolchain_file="toolchain.sha256"
+wget --no-verbose --no-clobber https://download.build2.org/toolchain.sha256 -O "${toolchain_file}"
+
+version_line=$(grep -m 1 '' "$toolchain_file")
+version_number=$(echo "$version_line" | awk '{print $2}')
+version_to_install=build2-install-${version_number}.sh
+download_url=https://download.build2.org/${version_number}/${version_to_install}
+wget --no-verbose --no-clobber "${download_url}" -O "${version_to_install}"
+
+## sha256 check phase
+
+line_with_version=$(grep "$version_to_install" "$toolchain_file")
+checksum_for_version=$(echo "$line_with_version" | awk '{print $1}')
+
+if echo "${checksum_for_version} ${version_to_install}" | sha256sum -c; then
+    echo "Build2 installer for version ${version_number} has been downloaded!"
+else
+    echo "Expected checksum for build2 installer version ${version_number} doesn't match! Probably the file has been corrupted! Please install it manually!" 1>&2
+    echo "Expected: ${checksum_for_version}" 1>&2
+    rm "$version_to_install" "$toolchain_file"
+    exit 1
+fi
+
+## install phase
+
+sh ${version_to_install} --yes --trust yes --jobs $(nproc) "${install_dir}"
+
+## cleanup phase
+
+compressed_toolchain="build2-toolchain-${version_number}.tar.xz"
+
+rm -f "${toolchain_file}" "${version_to_install}" "${compressed_toolchain}"
+
+echo "Build2 version ${version_number} has been successfully installed!"