[Buildroot] [PATCH 1/9 v4] core: do not hard-code inclusion of br2-external in Kconfig

[Yann E. MORIN <yann.morin.1998@free.fr>]

Move the inclusion of br2-external's Config.in to the generated kconfig
snippet.

This will ultimately allow us to use more than one br2-external tree.

Offload the "User-provided options" menu to the generated Kconfig
snippet. We can also move the definition of the Kconfig-version of
BR2_EXTERNAL into this snippet.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: Arnout Vandecappelle <arnout@mind.be>
Cc: Romain Naour <romain.naour@openwide.fr>
---
 Config.in                    | 11 ------
 Makefile                     |  2 +-
 support/scripts/br2-external | 85 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 86 insertions(+), 12 deletions(-)
 create mode 100755 support/scripts/br2-external

diff --git a/Config.in b/Config.in
index 3f53f25..65d8832 100644
--- a/Config.in
+++ b/Config.in
@@ -14,10 +14,6 @@ config BR2_HOSTARCH
 	string
 	option env="HOSTARCH"
 
-config BR2_EXTERNAL
-	string
-	option env="BR2_EXTERNAL"
-
 config BR2_BUILD_DIR
 	string
 	option env="BUILD_DIR"
@@ -761,11 +757,4 @@ source "package/Config.in.host"
 
 source "Config.in.legacy"
 
-menu "User-provided options"
-	depends on BR2_EXTERNAL != "support/dummy-external"
-
-source "$BR2_EXTERNAL/Config.in"
-
-endmenu
-
 source "$BR2_BUILD_DIR/.br2-external.in"
diff --git a/Makefile b/Makefile
index dfef021..513a989 100644
--- a/Makefile
+++ b/Makefile
@@ -886,7 +886,7 @@ endif
 # value of BR2_EXTERNAL is changed.
 .PHONY: $(BUILD_DIR)/.br2-external.in
 $(BUILD_DIR)/.br2-external.in: $(BUILD_DIR)
-	@touch $@
+	$(Q)support/scripts/br2-external -o "$(@)" $(BR2_EXTERNAL)
 
 # printvars prints all the variables currently defined in our
 # Makefiles. Alternatively, if a non-empty VARS variable is passed,
diff --git a/support/scripts/br2-external b/support/scripts/br2-external
new file mode 100755
index 0000000..c15c21c
--- /dev/null
+++ b/support/scripts/br2-external
@@ -0,0 +1,85 @@
+#!/bin/bash
+set -e
+
+# The location of the br2-external tree, once validated.
+declare BR2_EXT
+
+main() {
+    local OPT OPTARG
+    local br2_ext ofile
+
+    while getopts :ho: OPT; do
+        case "${OPT}" in
+        h)  help; exit 0;;
+        o)  ofile="${OPTARG}";;
+        :)  error "option '%s' expects a mandatory argument\n" "${OPTARG}";;
+        \?) error "unknown option '%s'\n" "${OPTARG}";;
+        esac
+    done
+    # Forget options; keep only positional args
+    shift $((OPTIND-1))
+
+    if [ ${#} -ne 1 ]; then
+        error "need exactly one br2-external tree to be specified\n"
+    fi
+    br2_ext="${1}"
+
+    if [ -z "${ofile}" ]; then
+        error "no output file specified (-o)\n"
+    fi
+
+    do_validate "${br2_ext}"
+
+    do_kconfig >"${ofile}"
+}
+
+# Validates the br2-external tree passed as argument. Makes it cannonical
+# and store it in global variable BR2_EXT.
+do_validate() {
+    local br2_ext="${1}"
+
+    if [ ! -d "${br2_ext}" ]; then
+        error "'%s': no such file or directory\n" "${br2_ext}"
+    fi
+
+    BR2_EXT="$(cd "${br2_ext}"; pwd -P )"
+}
+
+# Generate the kconfig snippet for the br2-external tree.
+do_kconfig() {
+    printf '#\n# Automatically generated file; DO NOT EDIT.\n#\n'
+    printf '\n'
+    printf 'config BR2_EXTERNAL\n'
+    printf '\tstring\n'
+    printf '\tdefault "%s"\n' "${BR2_EXT}"
+    printf '\n'
+    printf 'menu "User-provided options"\n'
+    printf '\tdepends on BR2_EXTERNAL != "support/dummy-external"\n'
+    printf '\n'
+    printf 'source "%s/Config.in"\n' "${BR2_EXT}"
+    printf '\n'
+    printf "endmenu # User-provided options\n"
+}
+
+help() {
+    cat <<-_EOF_
+	Usage:
+	    ${my_name} -o FILE PATH
+
+	${my_name} generates the kconfig snippet to include the configuration
+	options specified in the br2-external tree passed as positional argument.
+
+	Options:
+	    -o FILE
+	        FILE in which to generate the kconfig snippet.
+
+	Returns:
+	    0   If no error
+	    !0  If any error
+	_EOF_
+}
+
+error()  { local fmt="${1}"; shift; printf "%s: ${fmt}" "${my_name}" "${@}" >&2; exit 1; }
+
+my_name="${0##*/}"
+main "${@}"
-- 
2.7.4