首次提交

2026-07-13 12:06:16 +08:00
commit e3c810b1a6
1690 changed files with 228324 additions and 0 deletions
@@ -0,0 +1,56 @@
+'use strict'
+
+const { Transform, Writable } = require('stream')
+
+function validateTopic (topic, message) {
+  if (!topic || topic.length === 0) { // [MQTT-3.8.3-3]
+    return new Error('impossible to ' + message + ' to an empty topic')
+  }
+
+  const end = topic.length - 1
+  const endMinus = end - 1
+  const slashInPreEnd = endMinus > 0 && topic.charCodeAt(endMinus) !== 47
+
+  for (let i = 0; i < topic.length; i++) {
+    switch (topic.charCodeAt(i)) {
+      case 35: { // #
+        const notAtTheEnd = i !== end
+        if (notAtTheEnd || slashInPreEnd) {
+          return new Error('# is only allowed in ' + message + ' in the last position')
+        }
+        break
+      }
+      case 43: { // +
+        const pastChar = i < end - 1 && topic.charCodeAt(i + 1) !== 47
+        const preChar = i > 1 && topic.charCodeAt(i - 1) !== 47
+        if (pastChar || preChar) {
+          return new Error('+ is only allowed in ' + message + ' between /')
+        }
+        break
+      }
+    }
+  }
+}
+
+function through (transform) {
+  return new Transform({
+    objectMode: true,
+    transform
+  })
+}
+
+function bulk (fn) {
+  return new Writable({
+    objectMode: true,
+    writev: function (chunks, cb) {
+      fn(chunks.map(chunk => chunk.chunk), cb)
+    }
+  })
+}
+
+module.exports = {
+  validateTopic,
+  through,
+  bulk,
+  $SYS_PREFIX: '$SYS/'
+}