1 files changed, 192 insertions, 0 deletions
diff --git a/lib/dispatcher-base.js b/lib/dispatcher-base.js
new file mode 100644
index 0000000..5c0220b
--- /dev/null
+++ b/lib/dispatcher-base.js
@@ -0,0 +1,192 @@
+'use strict'
+
+const Dispatcher = require('./dispatcher')
+const {
+  ClientDestroyedError,
+  ClientClosedError,
+  InvalidArgumentError
+} = require('./core/errors')
+const { kDestroy, kClose, kDispatch, kInterceptors } = require('./core/symbols')
+
+const kDestroyed = Symbol('destroyed')
+const kClosed = Symbol('closed')
+const kOnDestroyed = Symbol('onDestroyed')
+const kOnClosed = Symbol('onClosed')
+const kInterceptedDispatch = Symbol('Intercepted Dispatch')
+
+class DispatcherBase extends Dispatcher {
+  constructor () {
+    super()
+
+    this[kDestroyed] = false
+    this[kOnDestroyed] = null
+    this[kClosed] = false
+    this[kOnClosed] = []
+  }
+
+  get destroyed () {
+    return this[kDestroyed]
+  }
+
+  get closed () {
+    return this[kClosed]
+  }
+
+  get interceptors () {
+    return this[kInterceptors]
+  }
+
+  set interceptors (newInterceptors) {
+    if (newInterceptors) {
+      for (let i = newInterceptors.length - 1; i >= 0; i--) {
+        const interceptor = this[kInterceptors][i]
+        if (typeof interceptor !== 'function') {
+          throw new InvalidArgumentError('interceptor must be an function')
+        }
+      }
+    }
+
+    this[kInterceptors] = newInterceptors
+  }
+
+  close (callback) {
+    if (callback === undefined) {
+      return new Promise((resolve, reject) => {
+        this.close((err, data) => {
+          return err ? reject(err) : resolve(data)
+        })
+      })
+    }
+
+    if (typeof callback !== 'function') {
+      throw new InvalidArgumentError('invalid callback')
+    }
+
+    if (this[kDestroyed]) {
+      queueMicrotask(() => callback(new ClientDestroyedError(), null))
+      return
+    }
+
+    if (this[kClosed]) {
+      if (this[kOnClosed]) {
+        this[kOnClosed].push(callback)
+      } else {
+        queueMicrotask(() => callback(null, null))
+      }
+      return
+    }
+
+    this[kClosed] = true
+    this[kOnClosed].push(callback)
+
+    const onClosed = () => {
+      const callbacks = this[kOnClosed]
+      this[kOnClosed] = null
+      for (let i = 0; i < callbacks.length; i++) {
+        callbacks[i](null, null)
+      }
+    }
+
+    // Should not error.
+    this[kClose]()
+      .then(() => this.destroy())
+      .then(() => {
+        queueMicrotask(onClosed)
+      })
+  }
+
+  destroy (err, callback) {
+    if (typeof err === 'function') {
+      callback = err
+      err = null
+    }
+
+    if (callback === undefined) {
+      return new Promise((resolve, reject) => {
+        this.destroy(err, (err, data) => {
+          return err ? /* istanbul ignore next: should never error */ reject(err) : resolve(data)
+        })
+      })
+    }
+
+    if (typeof callback !== 'function') {
+      throw new InvalidArgumentError('invalid callback')
+    }
+
+    if (this[kDestroyed]) {
+      if (this[kOnDestroyed]) {
+        this[kOnDestroyed].push(callback)
+      } else {
+        queueMicrotask(() => callback(null, null))
+      }
+      return
+    }
+
+    if (!err) {
+      err = new ClientDestroyedError()
+    }
+
+    this[kDestroyed] = true
+    this[kOnDestroyed] = this[kOnDestroyed] || []
+    this[kOnDestroyed].push(callback)
+
+    const onDestroyed = () => {
+      const callbacks = this[kOnDestroyed]
+      this[kOnDestroyed] = null
+      for (let i = 0; i < callbacks.length; i++) {
+        callbacks[i](null, null)
+      }
+    }
+
+    // Should not error.
+    this[kDestroy](err).then(() => {
+      queueMicrotask(onDestroyed)
+    })
+  }
+
+  [kInterceptedDispatch] (opts, handler) {
+    if (!this[kInterceptors] || this[kInterceptors].length === 0) {
+      this[kInterceptedDispatch] = this[kDispatch]
+      return this[kDispatch](opts, handler)
+    }
+
+    let dispatch = this[kDispatch].bind(this)
+    for (let i = this[kInterceptors].length - 1; i >= 0; i--) {
+      dispatch = this[kInterceptors][i](dispatch)
+    }
+    this[kInterceptedDispatch] = dispatch
+    return dispatch(opts, handler)
+  }
+
+  dispatch (opts, handler) {
+    if (!handler || typeof handler !== 'object') {
+      throw new InvalidArgumentError('handler must be an object')
+    }
+
+    try {
+      if (!opts || typeof opts !== 'object') {
+        throw new InvalidArgumentError('opts must be an object.')
+      }
+
+      if (this[kDestroyed] || this[kOnDestroyed]) {
+        throw new ClientDestroyedError()
+      }
+
+      if (this[kClosed]) {
+        throw new ClientClosedError()
+      }
+
+      return this[kInterceptedDispatch](opts, handler)
+    } catch (err) {
+      if (typeof handler.onError !== 'function') {
+        throw new InvalidArgumentError('invalid onError method')
+      }
+
+      handler.onError(err)
+
+      return false
+    }
+  }
+}
+
+module.exports = DispatcherBase