1 files changed, 111 insertions, 0 deletions
diff --git a/lib/utils/timers.js b/lib/utils/timers.js
new file mode 100644
index 000000000..acff29eb0
--- /dev/null
+++ b/lib/utils/timers.js
@@ -0,0 +1,111 @@
+const EE = require('events')
+const path = require('path')
+const fs = require('graceful-fs')
+const log = require('./log-shim')
+const withChownSync = require('./with-chown-sync.js')
+
+const _timeListener = Symbol('timeListener')
+const _timeEndListener = Symbol('timeEndListener')
+const _init = Symbol('init')
+
+// This is an event emiiter but on/off
+// only listen on a single internal event that gets
+// emitted whenever a timer ends
+class Timers extends EE {
+  #unfinished = new Map()
+  #finished = {}
+  #onTimeEnd = Symbol('onTimeEnd')
+  #dir = null
+  #initialListener = null
+  #initialTimer = null
+
+  constructor ({ listener = null, start = 'npm' } = {}) {
+    super()
+    this.#initialListener = listener
+    this.#initialTimer = start
+    this[_init]()
+  }
+
+  get unfinished () {
+    return this.#unfinished
+  }
+
+  get finished () {
+    return this.#finished
+  }
+
+  [_init] () {
+    this.on()
+    if (this.#initialListener) {
+      this.on(this.#initialListener)
+    }
+    process.emit('time', this.#initialTimer)
+    this.started = this.#unfinished.get(this.#initialTimer)
+  }
+
+  on (listener) {
+    if (listener) {
+      super.on(this.#onTimeEnd, listener)
+    } else {
+      process.on('time', this[_timeListener])
+      process.on('timeEnd', this[_timeEndListener])
+    }
+  }
+
+  off (listener) {
+    if (listener) {
+      super.off(this.#onTimeEnd, listener)
+    } else {
+      this.removeAllListeners(this.#onTimeEnd)
+      process.off('time', this[_timeListener])
+      process.off('timeEnd', this[_timeEndListener])
+    }
+  }
+
+  load ({ dir }) {
+    this.#dir = dir
+  }
+
+  writeFile (fileData) {
+    try {
+      const globalStart = this.started
+      const globalEnd = this.#finished.npm || Date.now()
+      const content = {
+        ...fileData,
+        ...this.#finished,
+        // add any unfinished timers with their relative start/end
+        unfinished: [...this.#unfinished.entries()].reduce((acc, [name, start]) => {
+          acc[name] = [start - globalStart, globalEnd - globalStart]
+          return acc
+        }, {}),
+      }
+      withChownSync(
+        path.resolve(this.#dir, '_timing.json'),
+        (f) =>
+          // we append line delimited json to this file...forever
+          // XXX: should we also write a process specific timing file?
+          // with similar rules to the debug log (max files, etc)
+          fs.appendFileSync(f, JSON.stringify(content) + '\n')
+      )
+    } catch (e) {
+      log.warn('timing', 'could not write timing file', e)
+    }
+  }
+
+  [_timeListener] = (name) => {
+    this.#unfinished.set(name, Date.now())
+  }
+
+  [_timeEndListener] = (name) => {
+    if (this.#unfinished.has(name)) {
+      const ms = Date.now() - this.#unfinished.get(name)
+      this.#finished[name] = ms
+      this.#unfinished.delete(name)
+      this.emit(this.#onTimeEnd, name, ms)
+    } else {
+      log.silly('timing', "Tried to end timer that doesn't exist:", name)
+    }
+  }
+}
+
+module.exports = Timers