benchmark: refactor to use process.send

This removes the need for parsing stdout from the benchmarks. If the
process wasn't executed by fork, it will just print like it used to.

This also fixes the parsing of CLI arguments, by inferring the type
from the options object instead of the value content.

Only two benchmarks had to be changed:

* http/http_server_for_chunky_client.js this previously used a spawn
now it uses a fork and relays the messages using common.sendResult.

* misc/v8-bench.js this utilized that v8/benchmark/run.js called
global.print and reformatted the input. It now interfaces directly
with the benchmark runner global.BenchmarkSuite.

PR-URL: #7094
Reviewed-By: Trevor Norris <trev.norris@gmail.com>
Reviewed-By: Jeremiah Senkpiel <fishrock123@rocketmail.com>
Reviewed-By: Brian White <mscdex@mscdex.net>
Reviewed-By: Anna Henningsen <anna@addaleax.net>

benchmark/_cli.js

@@ -0,0 +1,99 @@
+'use strict';
+
+const fs = require('fs');
+const path = require('path');
+
+// Create an object of all benchmark scripts
+const benchmarks = {};
+fs.readdirSync(__dirname)
+  .filter(function(name) {
+    return fs.statSync(path.resolve(__dirname, name)).isDirectory();
+  })
+  .forEach(function(category) {
+    benchmarks[category] = fs.readdirSync(path.resolve(__dirname, category))
+      .filter((filename) => filename[0] !== '.' && filename[0] !== '_');
+  });
+
+function CLI(usage, settings) {
+  if (!(this instanceof CLI)) return new CLI(usage, settings);
+
+  if (process.argv.length < 3) {
+    this.abort(usage); // abort will exit the process
+  }
+
+  this.usage = usage;
+  this.optional = {};
+  this.items = [];
+
+  for (const argName of settings.arrayArgs) {
+    this.optional[argName] = [];
+  }
+
+  let currentOptional = null;
+  let mode = 'both'; // possible states are: [both, option, item]
+
+  for (const arg of process.argv.slice(2)) {
+    if (arg === '--') {
+      // Only items can follow --
+      mode = 'item';
+    } else if (['both', 'option'].includes(mode) && arg[0] === '-') {
+      // Optional arguments declaration
+
+      if (arg[1] === '-') {
+        currentOptional = arg.slice(2);
+      } else {
+        currentOptional = arg.slice(1);
+      }
+
+      // Default the value to true
+      if (!settings.arrayArgs.includes(currentOptional)) {
+        this.optional[currentOptional] = true;
+      }
+
+      // expect the next value to be option related (either -- or the value)
+      mode = 'option';
+    } else if (mode === 'option') {
+      // Optional arguments value
+
+      if (settings.arrayArgs.includes(currentOptional)) {
+        this.optional[currentOptional].push(arg);
+      } else {
+        this.optional[currentOptional] = arg;
+      }
+
+      // the next value can be either an option or an item
+      mode = 'both';
+    } else if (['both', 'item'].includes(mode)) {
+      // item arguments
+      this.items.push(arg);
+
+      // the next value must be an item
+      mode = 'item';
+    } else {
+      // Bad case, abort
+      this.abort(usage);
+      return;
+    }
+  }
+}
+module.exports = CLI;
+
+CLI.prototype.abort = function(msg) {
+  console.error(msg);
+  process.exit(1);
+};
+
+CLI.prototype.benchmarks = function() {
+  const paths = [];
+  const filter = this.optional.filter || false;
+
+  for (const category of this.items) {
+    for (const scripts of benchmarks[category]) {
+      if (filter && scripts.lastIndexOf(filter) === -1) continue;
+
+      paths.push(path.join(category, scripts));
+    }
+  }
+
+  return paths;
+};