Use a custom script to copy resources (#2893)

All of those cpx invocations were getting unwieldy, and I suspect the exotic
quoting needed to run them under parallelshell was breaking things on windows.

Replace the unwieldy cpx invocations with an unwieldy custom script.

scripts/copy-res.js

@@ -0,0 +1,81 @@
+#!/usr/bin/env node
+
+// copies the resources into the webapp directory.
+//
+
+// cpx includes globbed parts of the filename in the destination, but excludes
+// common parents. Hence, "res/{a,b}/**": the output will be "dest/a/..." and
+// "dest/b/...".
+const COPY_LIST = [
+    ["res/{media,vector-icons}/**", "webapp"],
+    ["src/skins/vector/{fonts,img}/**", "webapp"],
+    ["node_modules/emojione/assets/svg/*", "webapp/emojione/svg/"],
+    ["./config.json", "webapp", {directwatch: 1}],
+];
+
+const parseArgs = require('minimist');
+const Cpx = require('cpx');
+const chokidar = require('chokidar');
+
+const argv = parseArgs(
+    process.argv.slice(2), {}
+);
+
+var watch = argv.w;
+var verbose = argv.v;
+
+function errCheck(err) {
+    if (err) {
+        console.error(err.message);
+        process.exit(1);
+    }
+}
+
+function next(i, err) {
+    errCheck(err);
+
+    if (i >= COPY_LIST.length) {
+        return;
+    }
+
+    const ent = COPY_LIST[i];
+    const source = ent[0];
+    const dest = ent[1];
+    const opts = ent[2] || {};
+
+    const cpx = new Cpx.Cpx(source, dest);
+
+    if (verbose) {
+        cpx.on("copy", (event) => {
+            console.log(`Copied: ${event.srcPath} --> ${event.dstPath}`);
+        });
+        cpx.on("remove", (event) => {
+            console.log(`Removed: ${event.path}`);
+        });
+    }
+
+    const cb = (err) => {next(i+1, err)};
+
+    if (watch) {
+        if (opts.directwatch) {
+            // cpx -w creates a watcher for the parent of any files specified,
+            // which in the case of config.json is '.', which inevitably takes
+            // ages to crawl. So we create our own watcher on the files
+            // instead.
+            const copy = () => {cpx.copy(errCheck)};
+            chokidar.watch(source)
+                .on('add', copy)
+                .on('change', copy)
+                .on('ready', cb)
+                .on('error', errCheck);
+        } else {
+            cpx.on('watch-ready', cb);
+            cpx.on("watch-error", cb);
+            cpx.watch();
+        }
+    } else {
+        cpx.copy(cb);
+    }
+}
+
+next(0);