-#!/bin/bash
+#!/usr/bin/env bash
# Set up the appropriate rustc toolchain
-cd $(dirname $0)
+set -e
-cargo install rustup-toolchain-install-master --debug || echo "rustup-toolchain-install-master already installed"
-RUSTC_HASH=$(git ls-remote https://github.com/rust-lang/rust.git master | awk '{print $1}')
-rustup-toolchain-install-master -f -n master $RUSTC_HASH
+cd "$(dirname "$0")"
+
+RTIM_PATH=$(command -v rustup-toolchain-install-master) || INSTALLED=false
+CARGO_HOME=${CARGO_HOME:-$HOME/.cargo}
+
+# Check if RTIM is not installed or installed in other locations not in ~/.cargo/bin
+if [[ "$INSTALLED" == false || "$RTIM_PATH" == $CARGO_HOME/bin/rustup-toolchain-install-master ]]; then
+ cargo +nightly install rustup-toolchain-install-master
+else
+ VERSION=$(rustup-toolchain-install-master -V | grep -o "[0-9.]*")
+ REMOTE=$(cargo +nightly search rustup-toolchain-install-master | grep -o "[0-9.]*")
+ echo "info: skipping updating rustup-toolchain-install-master at $RTIM_PATH"
+ echo " current version : $VERSION"
+ echo " remote version : $REMOTE"
+fi
+
+RUST_COMMIT=$(git ls-remote https://github.com/rust-lang/rust master | awk '{print $1}')
+
+if rustc +master -Vv 2>/dev/null | grep -q "$RUST_COMMIT"; then
+ echo "info: master toolchain is up-to-date"
+ exit 0
+fi
+
+if [[ -n "$HOST_TOOLCHAIN" ]]; then
+ TOOLCHAIN=('--host' "$HOST_TOOLCHAIN")
+else
+ TOOLCHAIN=()
+fi
+
+rustup-toolchain-install-master -f -n master "${TOOLCHAIN[@]}" -c rustc-dev -c llvm-tools -- "$RUST_COMMIT"
rustup override set master