feat: add cargo installer script

Signed-off-by: Patrick Kollitsch <patrick@davids-neighbour.com>

bin/helpers/cargo-install

@@ -0,0 +1,161 @@
+#!/bin/sh
+
+set -e
+
+help() {
+  cat <<'EOF'
+Install a binary release of a Rust crate hosted on GitHub
+
+Usage:
+    install.sh [options]
+
+Options:
+    -h, --help      Display this message
+    --git SLUG      Get the crate from "https://github/$SLUG"
+    -f, --force     Force overwriting an existing binary
+    --crate NAME    Name of the crate to install (default <repository name>)
+    --tag TAG       Tag (version) of the crate to install (default <latest release>)
+    --target TARGET Install the release compiled for $TARGET (default <`rustc` host>)
+    --to LOCATION   Where to install the binary (default ~/.cargo/bin)
+EOF
+}
+
+say() {
+  echo "install.sh: $1"
+}
+
+say_err() {
+  say "$1" >&2
+}
+
+err() {
+  if [ -n "$td" ]; then
+    rm -rf "$td"
+  fi
+
+  say_err "ERROR $1"
+  exit 1
+}
+
+need() {
+  if ! command -v "$1" >/dev/null 2>&1; then
+    err "need $1 (command not found)"
+  fi
+}
+
+force=false
+while test $# -gt 0; do
+  case $1 in
+  --crate)
+    crate=$2
+    shift
+    ;;
+  --force | -f)
+    force=true
+    ;;
+  --git)
+    git=$2
+    shift
+    ;;
+  --help | -h)
+    help
+    exit 0
+    ;;
+  --tag)
+    tag=$2
+    shift
+    ;;
+  --target)
+    target=$2
+    shift
+    ;;
+  --to)
+    dest=$2
+    shift
+    ;;
+  *) ;;
+  esac
+  shift
+done
+
+# Dependencies
+need basename
+need curl
+need install
+need mkdir
+need mktemp
+need tar
+
+# Optional dependencies
+if [ -z "$crate" ] || [ -z "$tag" ] || [ -z "$target" ]; then
+  need cut
+fi
+
+if [ -z "$tag" ]; then
+  need rev
+fi
+
+if [ -z "$target" ]; then
+  need grep
+  need rustc
+fi
+
+if [ -z "$git" ]; then
+  # Markdown-style backticks
+  # shellcheck disable=SC2016
+  err 'must specify a git repository using `--git`. Example: `install.sh --git japaric/cross`'
+fi
+
+url="https://github.com/$git"
+say_err "GitHub repository: $url"
+
+if [ -z "$crate" ]; then
+  crate=$(echo "$git" | cut -d'/' -f2)
+fi
+
+say_err "Crate: $crate"
+
+url="$url/releases"
+
+if [ -z "$tag" ]; then
+  latest_url=$url/latest
+  tag_url=$(curl -Ls -o /dev/null -w "%{url_effective}" "$latest_url")
+  tag=$(echo "$tag_url" | rev | cut -d'/' -f1 | rev)
+  if [ -z "$tag" ]; then
+    err "Failed to get tag from $latest_url"
+  fi
+  say_err "Tag: latest ($tag)"
+else
+  say_err "Tag: $tag"
+fi
+
+if [ -z "$target" ]; then
+  target=$(rustc -Vv | grep host | cut -d' ' -f2)
+fi
+
+say_err "Target: $target"
+
+if [ -z "$dest" ]; then
+  dest="$HOME/.cargo/bin"
+fi
+
+say_err "Installing to: $dest"
+
+url="$url/download/$tag/$crate-$tag-$target.tar.gz"
+
+td=$(mktemp -d || mktemp -d -t tmp)
+curl -sL "$url" | tar xz -f - -C "$td"
+
+for f in "$td"/*; do
+  test -x "$f" || continue
+  test -f "$f" || continue
+
+  if [ -e "$dest/$(basename "$f")" ] && [ "$force" = false ]; then
+    err "$f already exists in $dest"
+  else
+    mkdir -p "$dest"
+    install -m 755 "$f" "$dest"
+  fi
+done
+
+rm -rf "$td"