Reduce cache size further by not adding build dir to it

generate.sh

@@ -39,8 +39,7 @@ exec_dockerstage() {
         STG="$(ffbuild_dockerdl)"
         if [[ -n "$STG" ]]; then
             HASH="$(sha256sum <<<"$STG" | cut -d" " -f1)"
-            to_df "ADD .cache/downloads/${STAGENAME}_${HASH}.tar.xz /${STAGENAME}"
-            to_df "WORKDIR /${STAGENAME}"
+            export SELFCACHE=".cache/downloads/${STAGENAME}_${HASH}.tar.xz"
         fi
 
         ffbuild_dockerstage || exit $?

scripts.d/50-aom.sh

@@ -8,7 +8,7 @@ ffbuild_enabled() {
 }
 
 ffbuild_dockerstage() {
-    to_df "RUN --mount=src=${SELF},dst=/stage.sh --mount=src=patches/aom,dst=/patches run_stage /stage.sh"
+    to_df "RUN --mount=src=${SELF},dst=/stage.sh --mount=src=${SELFCACHE},dst=/cache.tar.xz --mount=src=patches/aom,dst=/patches run_stage /stage.sh"
 }
 
 ffbuild_dockerbuild() {

scripts.d/50-aribb24/50-libaribb24.sh

@@ -8,7 +8,7 @@ ffbuild_enabled() {
 }
 
 ffbuild_dockerstage() {
-    to_df "RUN --mount=src=${SELF},dst=/stage.sh --mount=src=patches/aribb24,dst=/patches run_stage /stage.sh"
+    to_df "RUN --mount=src=${SELF},dst=/stage.sh --mount=src=${SELFCACHE},dst=/cache.tar.xz --mount=src=patches/aribb24,dst=/patches run_stage /stage.sh"
 }
 
 ffbuild_dockerbuild() {

scripts.d/50-zvbi.sh

@@ -8,7 +8,7 @@ ffbuild_enabled() {
 }
 
 ffbuild_dockerstage() {
-    to_df "RUN --mount=src=${SELF},dst=/stage.sh --mount=src=patches/zvbi,dst=/patches run_stage /stage.sh"
+    to_df "RUN --mount=src=${SELF},dst=/stage.sh --mount=src=${SELFCACHE},dst=/cache.tar.xz --mount=src=patches/zvbi,dst=/patches run_stage /stage.sh"
 }
 
 ffbuild_dockerdl() {

util/run_stage.sh

@@ -8,6 +8,15 @@ export RAW_LDFLAGS="$LDFLAGS"
 [[ -n "$STAGE_CXXFLAGS" ]] && export CXXFLAGS="$CXXFLAGS $STAGE_CXXFLAGS"
 [[ -n "$STAGE_LDFLAGS" ]] && export LDFLAGS="$LDFLAGS $STAGE_LDFLAGS"
 
+if [[ -n "$STAGENAME" && -f /cache.tar.xz ]]; then
+    mkdir -p "/$STAGENAME"
+    tar xaf /cache.tar.xz -C "/$STAGENAME"
+    cd "/$STAGENAME"
+elif [[ -n "$STAGENAME" ]]; then
+    mkdir -p "/$STAGENAME"
+    cd "/$STAGENAME"
+fi
+
 git config --global --add safe.directory "$PWD"
 
 source "$1"

util/vars.sh

@@ -38,7 +38,11 @@ TARGET_IMAGE="${REGISTRY}/${REPO}/base-${TARGET}:latest"
 IMAGE="${REGISTRY}/${REPO}/${TARGET}-${VARIANT}${ADDINS_STR:+-}${ADDINS_STR}:latest"
 
 ffbuild_dockerstage() {
-    to_df "RUN --mount=src=${SELF},dst=/stage.sh run_stage /stage.sh"
+    if [[ -n "$SELFCACHE" ]]; then
+        to_df "RUN --mount=src=${SELF},dst=/stage.sh --mount=src=${SELFCACHE},dst=/cache.tar.xz run_stage /stage.sh"
+    else
+        to_df "RUN --mount=src=${SELF},dst=/stage.sh run_stage /stage.sh"
+    fi
 }
 
 ffbuild_dockerlayer() {