javascript.sh

#!/bin/bash

# Keeps the shipped JS bundles in sync with their CoffeeScript sources.
#
# The committed files BirchOutline/BirchOutline.swift/Dependencies/birchoutline.js and
# BirchEditor/BirchEditor.swift/Dependencies/bircheditor.js are the canonical build
# inputs — a fresh clone builds the app from them with no JS toolchain installed.
# Next to each bundle lives a committed .sha256 manifest recording (a) a hash of the
# bundle's inputs (src/**, gulp/webpack config, package.json, package-lock.json) and
# (b) a hash of the bundle itself.
#
# When manifests match, this script is a no-op (no Node required). When sources have
# changed, it rebuilds with gulp (Node v11.15.0 — the gulp 3 toolchain does not run on
# newer Node), refreshes the bundles and manifests, and tells you to commit them
# together with the source changes. If a rebuild is needed but impossible or fails,
# the Xcode build fails loudly instead of silently shipping stale bundles.

set -euo pipefail

# Hashes depend on `sort` order, which is locale-dependent — pin it.
export LC_ALL=C

ROOT="$(cd "$(dirname "$0")" && pwd)"

OUTLINE_PKG="$ROOT/BirchOutline/birch-outline.js"
EDITOR_PKG="$ROOT/BirchEditor/birch-editor.js"
OUTLINE_DEP="$ROOT/BirchOutline/BirchOutline.swift/Dependencies/birchoutline.js"
EDITOR_DEP="$ROOT/BirchEditor/BirchEditor.swift/Dependencies/bircheditor.js"
OUTLINE_MANIFEST="$OUTLINE_DEP.sha256"
EDITOR_MANIFEST="$EDITOR_DEP.sha256"

REBUILD_HINT="rebuild with: nvm use v11.15.0 && ./javascript.sh, then commit the updated Dependencies/*.js and *.sha256 files"

fail() {
    echo "error: $1" >&2
    exit 1
}

file_hash() {
    shasum -a 256 "$1" | cut -d' ' -f1
}

# Hash of everything that determines a package's bundle bytes.
inputs_hash() {
    (
        cd "$1"
        {
            find src -type f ! -name .DS_Store | sort
            echo gulpfile.coffee
            echo webpack.config.coffee
            echo package.json
            echo package-lock.json
        } | xargs shasum -a 256 | shasum -a 256 | cut -d' ' -f1
    )
}

manifest_matches() {
    local manifest="$1" inputs="$2" bundle="$3"
    [ -f "$manifest" ] && [ -f "$bundle" ] || return 1
    [ "$(sed -n 's/^inputs //p' "$manifest")" = "$inputs" ] || return 1
    [ "$(sed -n 's/^bundle //p' "$manifest")" = "$(file_hash "$bundle")" ] || return 1
}

write_manifest() {
    local manifest="$1" inputs="$2" bundle="$3"
    printf 'inputs %s\nbundle %s\n' "$inputs" "$(file_hash "$bundle")" > "$manifest"
}

# True when min/<bundle> exists and no input is newer (e.g. `npm run start` gulp-watch
# already rebuilt it) — then we can skip gulp and just copy.
min_is_fresh() {
    local pkg="$1" out="$2"
    shift 2
    [ -f "$pkg/min/$out" ] || return 1
    [ -z "$(cd "$pkg" && find src gulpfile.coffee webpack.config.coffee package.json package-lock.json "$@" -newer "min/$out" -print -quit)" ]
}

ensure_toolchain() {
    local nvm_bin="$HOME/.nvm/versions/node/v11.15.0/bin"
    if [ -x "$nvm_bin/node" ]; then
        export PATH="$nvm_bin:$PATH"
    fi
    case "$(node -v 2>/dev/null || true)" in
        v11.*) ;;
        *) fail "JS sources changed but Node v11.15.0 was not found (the gulp 3 toolchain requires it). Install with: nvm install v11.15.0 — then $REBUILD_HINT" ;;
    esac
    for pkg in "$OUTLINE_PKG" "$EDITOR_PKG"; do
        [ -f "$pkg/node_modules/gulp/bin/gulp.js" ] || fail "JS sources changed but $pkg/node_modules is missing. Run: cd $pkg && npm install (with Node v11.15.0), then $REBUILD_HINT"
    done
}

STAMP="$(mktemp)"
trap 'rm -f "$STAMP"' EXIT

gulp_prepublish() {
    echo "Rebuilding JS bundle in $1 ..."
    ensure_toolchain
    (cd "$1" && ./node_modules/gulp/bin/gulp.js prepublish) || fail "gulp prepublish failed in $1 — fix the JS build, then $REBUILD_HINT"
}

# gulp 3 swallows CoffeeScript compile errors and doesn't await webpack, so verify the
# output actually got (re)written rather than trusting gulp's exit status.
verify_min() {
    local f="$1"
    [ -f "$f" ] || fail "$f was not produced by gulp prepublish — fix the JS build, then $REBUILD_HINT"
    [ "$(stat -f %z "$f")" -gt 100000 ] || fail "$f is suspiciously small — the JS build likely failed; fix it, then $REBUILD_HINT"
    [ "$f" -nt "$STAMP" ] || fail "$f was not regenerated by gulp prepublish (a CoffeeScript error may have been swallowed) — fix the JS build, then $REBUILD_HINT"
}

update_bundle() {
    local min="$1" dep="$2" manifest="$3" inputs="$4"
    cp "$min" "$dep"
    write_manifest "$manifest" "$inputs" "$dep"
    echo "Updated $dep — commit it (and its .sha256 manifest) together with the JS source changes."
}

OUTLINE_INPUTS="$(inputs_hash "$OUTLINE_PKG")"
# The editor bundle embeds birch-outline (npm file: link), so its inputs include the outline's.
EDITOR_INPUTS="$(printf '%s\n%s\n' "$(inputs_hash "$EDITOR_PKG")" "$OUTLINE_INPUTS" | shasum -a 256 | cut -d' ' -f1)"

outline_ok=0; manifest_matches "$OUTLINE_MANIFEST" "$OUTLINE_INPUTS" "$OUTLINE_DEP" || outline_ok=1
editor_ok=0; manifest_matches "$EDITOR_MANIFEST" "$EDITOR_INPUTS" "$EDITOR_DEP" || editor_ok=1

if [ "$outline_ok" -eq 0 ] && [ "$editor_ok" -eq 0 ]; then
    exit 0
fi

if [ "$outline_ok" -ne 0 ]; then
    if ! min_is_fresh "$OUTLINE_PKG" birchoutline.js; then
        gulp_prepublish "$OUTLINE_PKG"
        verify_min "$OUTLINE_PKG/min/birchoutline.js"
    fi
    update_bundle "$OUTLINE_PKG/min/birchoutline.js" "$OUTLINE_DEP" "$OUTLINE_MANIFEST" "$OUTLINE_INPUTS"
fi

if [ "$editor_ok" -ne 0 ]; then
    # The editor's webpack resolves birch-outline through its gitignored lib/ output,
    # which must exist and be current before the editor bundle can build.
    if [ ! -f "$OUTLINE_PKG/lib/index.js" ] || ! min_is_fresh "$OUTLINE_PKG" birchoutline.js; then
        gulp_prepublish "$OUTLINE_PKG"
    fi
    if ! min_is_fresh "$EDITOR_PKG" bircheditor.js "$OUTLINE_PKG/src"; then
        gulp_prepublish "$EDITOR_PKG"
        verify_min "$EDITOR_PKG/min/bircheditor.js"
    fi
    update_bundle "$EDITOR_PKG/min/bircheditor.js" "$EDITOR_DEP" "$EDITOR_MANIFEST" "$EDITOR_INPUTS"
fi