1 files changed, 112 insertions, 0 deletions
diff --git a/devtools/client/fronts/descriptors/process.js b/devtools/client/fronts/descriptors/process.js
new file mode 100644
index 0000000000..0d0602920b
--- /dev/null
+++ b/devtools/client/fronts/descriptors/process.js
@@ -0,0 +1,112 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+"use strict";
+
+const {
+  processDescriptorSpec,
+} = require("devtools/shared/specs/descriptors/process");
+const {
+  BrowsingContextTargetFront,
+} = require("devtools/client/fronts/targets/browsing-context");
+const {
+  ContentProcessTargetFront,
+} = require("devtools/client/fronts/targets/content-process");
+const {
+  FrontClassWithSpec,
+  registerFront,
+} = require("devtools/shared/protocol");
+
+class ProcessDescriptorFront extends FrontClassWithSpec(processDescriptorSpec) {
+  constructor(client, targetFront, parentFront) {
+    super(client, targetFront, parentFront);
+    this.isParent = false;
+    this._processTargetFront = null;
+    this._targetFrontPromise = null;
+    this._client = client;
+  }
+
+  form(json) {
+    this.id = json.id;
+    this.isParent = json.isParent;
+    this.traits = json.traits || {};
+  }
+
+  async _createProcessTargetFront(form) {
+    let front = null;
+    // the request to getTarget may return a ContentProcessTargetActor or a
+    // ParentProcessTargetActor. In most cases getProcess(0) will return the
+    // main process target actor, which is a ParentProcessTargetActor, but
+    // not in xpcshell, which uses a ContentProcessTargetActor. So select
+    // the right front based on the actor ID.
+    if (form.actor.includes("parentProcessTarget")) {
+      // ParentProcessTargetActor doesn't have a specific front, instead it uses
+      // BrowsingContextTargetFront on the client side.
+      front = new BrowsingContextTargetFront(this._client, null, this);
+    } else {
+      front = new ContentProcessTargetFront(this._client, null, this);
+    }
+    // As these fronts aren't instantiated by protocol.js, we have to set their actor ID
+    // manually like that:
+    front.actorID = form.actor;
+    front.form(form);
+
+    // @backward-compat { version 84 } Older server don't send the processID in the form
+    if (!front.processID) {
+      front.processID = this.id;
+    }
+
+    this.manage(front);
+    return front;
+  }
+
+  getCachedTarget() {
+    return this._processTargetFront;
+  }
+
+  async getTarget() {
+    // Only return the cached Target if it is still alive.
+    if (this._processTargetFront && !this._processTargetFront.isDestroyed()) {
+      return this._processTargetFront;
+    }
+    // Otherwise, ensure that we don't try to spawn more than one Target by
+    // returning the pending promise
+    if (this._targetFrontPromise) {
+      return this._targetFrontPromise;
+    }
+    this._targetFrontPromise = (async () => {
+      let targetFront = null;
+      try {
+        const targetForm = await super.getTarget();
+        targetFront = await this._createProcessTargetFront(targetForm);
+        await targetFront.attach();
+      } catch (e) {
+        // This is likely to happen if we get a lot of events which drop previous
+        // processes.
+        console.log(
+          `Request to connect to ProcessDescriptor "${this.id}" failed: ${e}`
+        );
+      }
+      // Save the reference to the target only after the call to attach
+      // so that getTarget always returns the attached target in case of concurrent calls
+      this._processTargetFront = targetFront;
+      // clear the promise if we are finished so that we can re-connect if
+      // necessary
+      this._targetFrontPromise = null;
+      return targetFront;
+    })();
+    return this._targetFrontPromise;
+  }
+
+  destroy() {
+    if (this._processTargetFront) {
+      this._processTargetFront.destroy();
+      this._processTargetFront = null;
+    }
+    this._targetFrontPromise = null;
+    super.destroy();
+  }
+}
+
+exports.ProcessDescriptorFront = ProcessDescriptorFront;
+registerFront(ProcessDescriptorFront);