From c419c549b9a1db32d307ae5a6ad62f6b41540e78 Mon Sep 17 00:00:00 2001
From: BtbN <btbn@btbn.de>
Date: Tue, 6 Apr 2021 03:41:36 +0200
Subject: [PATCH] Add fully layered build

---
 generate.sh                                | 72 ++++++++++++++++++----
 scripts.d/10-mingw.sh                      |  8 +++
 scripts.d/{21-libxml2.sh => 20-libxml2.sh} |  0
 util/vars.sh                               |  8 +++
 4 files changed, 77 insertions(+), 11 deletions(-)
 rename scripts.d/{21-libxml2.sh => 20-libxml2.sh} (100%)

diff --git a/generate.sh b/generate.sh
index fbfe5ed..b5ceb93 100755
--- a/generate.sh
+++ b/generate.sh
@@ -5,19 +5,69 @@ source util/vars.sh
 
 rm -f Dockerfile
 
-to_df() {
-    printf "$@" >> Dockerfile
-    echo >> Dockerfile
+layername() {
+    printf "layer-"
+    basename "$1" | sed 's/.sh$//'
 }
 
-to_df "FROM ${REGISTRY}/${REPO}/base-${TARGET}:latest"
+exec_dockerstage() {
+    SCRIPT="$1"
+    (
+        SELF="$SCRIPT"
+        source "$SCRIPT"
+        ffbuild_enabled || exit 0
+        ffbuild_dockerstage || exit $?
+    )
+}
+
+to_df() {
+    _of="${TODF:-Dockerfile}"
+    printf "$@" >> "$_of"
+    echo >> "$_of"
+}
+
+to_df "FROM ${REGISTRY}/${REPO}/base-${TARGET}:latest AS base"
 to_df "ENV TARGET=$TARGET VARIANT=$VARIANT REPO=$REPO ADDINS_STR=$ADDINS_STR"
 
-for script in scripts.d/*.sh; do
-(
-    SELF="$script"
-    source $script
-    ffbuild_enabled || exit 0
-    ffbuild_dockerstage || exit $?
-)
+PREVLAYER="base"
+for ID in $(ls -1d scripts.d/??-* | sed -s 's|^.*/\(..\).*|\1|' | sort -u); do
+    LAYER="layer-$ID"
+
+    for STAGE in scripts.d/$ID-*; do
+        to_df "FROM $PREVLAYER AS $(layername "$STAGE")"
+
+        if [[ -f "$STAGE" ]]; then
+            exec_dockerstage "$STAGE"
+        else
+            for STAGE in "${STAGE}"/??-*; do
+                exec_dockerstage "$STAGE"
+            done
+        fi
+    done
+
+    to_df "FROM $PREVLAYER AS $LAYER"
+    for STAGE in scripts.d/$ID-*; do
+        if [[ -f "$STAGE" ]]; then
+            SCRIPT="$STAGE"
+        else
+            SCRIPTS=( "$STAGE"/??-* )
+            SCRIPT="${SCRIPTS[-1]}"
+        fi
+
+        (
+            SELF="$SCRIPT"
+            SELFLAYER="$(layername "$STAGE")"
+            source "$SCRIPT"
+            ffbuild_enabled || exit 0
+            ffbuild_dockerlayer || exit $?
+            TODF="Dockerfile.final" PREVLAYER="__PREVLAYER__" \
+                ffbuild_dockerfinal || exit $?
+        )
+    done
+
+    PREVLAYER="$LAYER"
 done
+
+to_df "FROM base"
+sed "s/__PREVLAYER__/$PREVLAYER/g" Dockerfile.final | sort -u >> Dockerfile
+rm Dockerfile.final
diff --git a/scripts.d/10-mingw.sh b/scripts.d/10-mingw.sh
index 4a7c198..aba0743 100755
--- a/scripts.d/10-mingw.sh
+++ b/scripts.d/10-mingw.sh
@@ -8,6 +8,14 @@ ffbuild_enabled() {
     return 0
 }
 
+ffbuild_dockerlayer() {
+    to_df "COPY --from=${SELFLAYER} /usr/\$FFBUILD_TOOLCHAIN/. /usr/\$FFBUILD_TOOLCHAIN"
+}
+
+ffbuild_dockerfinal() {
+    to_df "COPY --from=${PREVLAYER} /usr/\$FFBUILD_TOOLCHAIN/. /usr/\$FFBUILD_TOOLCHAIN"
+}
+
 ffbuild_dockerbuild() {
     git-mini-clone "$MINGW_REPO" "$MINGW_COMMIT" mingw
     cd mingw/mingw-w64-headers
diff --git a/scripts.d/21-libxml2.sh b/scripts.d/20-libxml2.sh
similarity index 100%
rename from scripts.d/21-libxml2.sh
rename to scripts.d/20-libxml2.sh
diff --git a/util/vars.sh b/util/vars.sh
index 1be3bb1..f8643e3 100644
--- a/util/vars.sh
+++ b/util/vars.sh
@@ -39,6 +39,14 @@ ffbuild_dockerstage() {
     to_df "RUN --mount=src=${SELF},dst=/stage.sh run_stage /stage.sh"
 }
 
+ffbuild_dockerlayer() {
+    to_df "COPY --from=${SELFLAYER} \$FFBUILD_PREFIX/. \$FFBUILD_PREFIX"
+}
+
+ffbuild_dockerfinal() {
+    to_df "COPY --from=${PREVLAYER} \$FFBUILD_PREFIX/. \$FFBUILD_PREFIX"
+}
+
 ffbuild_configure() {
     return 0
 }