1 files changed, 137 insertions, 0 deletions
diff --git a/src/lib/job-pool.source.sh b/src/lib/job-pool.source.sh
new file mode 100644
index 0000000..5c629aa
--- /dev/null
+++ b/src/lib/job-pool.source.sh
@@ -0,0 +1,137 @@
+wait_for_parallel_job_pid() {
+    local -r pid="$1"; shift
+    local -i status=0
+
+    set +e
+    wait "$pid"
+    status=$?
+    set -e
+
+    return "$status"
+}
+
+parallel_job_pid_is_running() {
+    local -r pid="$1"; shift
+    local running_pid
+
+    for running_pid in "$@"; do
+        if [ "$running_pid" = "$pid" ]; then
+            return 0
+        fi
+    done
+
+    return 1
+}
+
+reap_finished_parallel_jobs() {
+    local -r job_pids_name="$1"; shift
+    # shellcheck disable=SC2178
+    local -n job_pids_ref="$job_pids_name"
+    local -n failed_ref="$1"; shift
+    local -i reaped_status="$1"; shift
+    local -i has_reaped_status=1
+    local -i status=0
+    local -a remaining_pids=()
+    local -a running_pids=()
+    local pid
+
+    mapfile -t running_pids < <(jobs -rp)
+
+    for pid in "${job_pids_ref[@]}"; do
+        if parallel_job_pid_is_running "$pid" "${running_pids[@]}"; then
+            remaining_pids+=("$pid")
+            continue
+        fi
+
+        if wait_for_parallel_job_pid "$pid"; then
+            status=0
+        else
+            status=$?
+        fi
+        if (( status == 127 && has_reaped_status != 0 )); then
+            status=$reaped_status
+            has_reaped_status=0
+        fi
+
+        if (( status != 0 )); then
+            failed_ref=1
+        fi
+    done
+
+    job_pids_ref=("${remaining_pids[@]}")
+}
+
+wait_for_next_parallel_job() {
+    local -r job_pids_name="$1"; shift
+    local -r failed_name="$1"; shift
+    # shellcheck disable=SC2178
+    local -n job_pids_ref="$job_pids_name"
+    local -i status=0
+
+    set +e
+    wait -n "${job_pids_ref[@]}"
+    status=$?
+    set -e
+
+    reap_finished_parallel_jobs "$job_pids_name" "$failed_name" "$status"
+}
+
+wait_for_parallel_job_slot() {
+    local -r job_pids_name="$1"; shift
+    local -r failed_name="$1"; shift
+    local -r max_jobs="$1"; shift
+    # shellcheck disable=SC2178
+    local -n job_pids_ref="$job_pids_name"
+
+    while (( ${#job_pids_ref[@]} >= max_jobs )); do
+        wait_for_next_parallel_job "$job_pids_name" "$failed_name"
+    done
+}
+
+wait_for_parallel_jobs() {
+    # shellcheck disable=SC2178
+    local -n job_pids_ref="$1"; shift
+    local -n failed_ref="$1"; shift
+
+    : "$failed_ref"
+    while (( ${#job_pids_ref[@]} > 0 )); do
+        if ! wait_for_parallel_job_pid "${job_pids_ref[0]}"; then
+            failed_ref=1
+        fi
+        job_pids_ref=("${job_pids_ref[@]:1}")
+    done
+}
+
+wait_for_image_job_slot() {
+    local -r image_job_pids_name="$1"; shift
+    local -r failed_name="$1"; shift
+
+    wait_for_parallel_job_slot \
+        "$image_job_pids_name" \
+        "$failed_name" \
+        "$IMAGE_JOBS"
+}
+
+wait_for_image_jobs() {
+    local -r image_job_pids_name="$1"; shift
+    local -r failed_name="$1"; shift
+
+    wait_for_parallel_jobs "$image_job_pids_name" "$failed_name"
+}
+
+wait_for_template_render_job_slot() {
+    local -r render_job_pids_name="$1"; shift
+    local -r failed_name="$1"; shift
+
+    wait_for_parallel_job_slot \
+        "$render_job_pids_name" \
+        "$failed_name" \
+        "$IMAGE_JOBS"
+}
+
+wait_for_template_render_jobs() {
+    local -r render_job_pids_name="$1"; shift
+    local -r failed_name="$1"; shift
+
+    wait_for_parallel_jobs "$render_job_pids_name" "$failed_name"
+}