Add build_test.sh, split common parts of soong_ui.bash

Move common microfactory functions to cmd/microfactory/microfactory.bash
so that they can be used to build both soong_ui for normal build and
multiproduct_kati for build system tests.

Test: m -j
Test: build/soong/build_test.bash
Change-Id: I9512642d846ce54d05a027b6d33a2b3029b3f90b

cmd/microfactory/microfactory.bash

@@ -0,0 +1,88 @@
+# Copyright 2017 Google Inc. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# Set of utility functions to build and run go code with microfactory
+#
+# Inputs:
+#  ${TOP}: The top of the android source tree
+#  ${OUT_DIR}: The output directory location (defaults to ${TOP}/out)
+#  ${OUT_DIR_COMMON_BASE}: Change the default out directory to
+#    ${OUT_DIR_COMMON_BASE}/$(basename ${TOP})
+
+# Ensure GOROOT is set to the in-tree version.
+case $(uname) in
+    Linux)
+        export GOROOT="${TOP}/prebuilts/go/linux-x86/"
+        ;;
+    Darwin)
+        export GOROOT="${TOP}/prebuilts/go/darwin-x86/"
+        ;;
+    *) echo "unknown OS:" $(uname) >&2 && exit 1;;
+esac
+
+# Find the output directory
+function getoutdir
+{
+    local out_dir="${OUT_DIR-}"
+    if [ -z "${out_dir}" ]; then
+        if [ "${OUT_DIR_COMMON_BASE-}" ]; then
+            out_dir="${OUT_DIR_COMMON_BASE}/$(basename ${TOP})"
+        else
+            out_dir="${TOP}/out"
+        fi
+    fi
+    echo "${out_dir}"
+}
+
+# Bootstrap microfactory from source if necessary and use it to build the
+# requested binary.
+#
+# Arguments:
+#  $1: name of the requested binary
+#  $2: package name
+function build_go
+{
+    # Increment when microfactory changes enough that it cannot rebuild itself.
+    # For example, if we use a new command line argument that doesn't work on older versions.
+    local mf_version=2
+
+    local mf_src="${TOP}/build/soong/cmd/microfactory"
+
+    local out_dir=$(getoutdir)
+    local mf_bin="${out_dir}/microfactory_$(uname)"
+    local mf_version_file="${out_dir}/.microfactory_$(uname)_version"
+    local built_bin="${out_dir}/$1"
+    local from_src=1
+
+    if [ -f "${mf_bin}" ] && [ -f "${mf_version_file}" ]; then
+        if [ "${mf_version}" -eq "$(cat "${mf_version_file}")" ]; then
+            from_src=0
+        fi
+    fi
+
+    local mf_cmd
+    if [ $from_src -eq 1 ]; then
+        mf_cmd="${GOROOT}/bin/go run ${mf_src}/microfactory.go"
+    else
+        mf_cmd="${mf_bin}"
+    fi
+
+    ${mf_cmd} -s "${mf_src}" -b "${mf_bin}" \
+            -pkg-path "android/soong=${TOP}/build/soong" -trimpath "${TOP}/build/soong" \
+            -o "${built_bin}" $2
+
+    if [ $from_src -eq 1 ]; then
+        echo "${mf_version}" >"${mf_version_file}"
+    fi
+}