#!/usr/bin/env bash
# Use sccache for rustc when it is installed. It is a developer convenience, never a requirement:
# without it nothing is exported and a clone needs only stable Rust and a C compiler.
#
# Sourced, it exports RUSTC_WRAPPER into the current shell for later cargo commands; run with a
# command, it wraps just that command. The verify, land and smoke scripts source it themselves.
#
#   . scripts/sccache.sh && cargo play
#   scripts/sccache.sh cargo play
#
# An existing RUSTC_WRAPPER wins, BENILLA_NO_SCCACHE=1 skips this, and SCCACHE_DISABLE=1 turns
# sccache itself off. Only rustc is wrapped: the vendored Lua build wants its own `CC="sccache cc"`.
# Sourced, it must not change the caller's shell options.
enable() {
    [ -n "${RUSTC_WRAPPER:-}" ] && return 0
    [ -n "${BENILLA_NO_SCCACHE:-}" ] && return 0
    command -v sccache >/dev/null 2>&1 || return 0
    export RUSTC_WRAPPER=sccache
}

enable
# Executed with a command: run it wrapped. Sourced: leave the caller's positionals alone.
if [ "${BASH_SOURCE[0]}" = "$0" ] && [ "$#" -gt 0 ]; then
    exec "$@"
fi