EmbeddedWorker, browser side code

content/browser/service_worker/embedded_worker_instance.cc

+// Copyright 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "content/browser/service_worker/embedded_worker_instance.h"
+
+#include "content/browser/service_worker/embedded_worker_registry.h"
+#include "url/gurl.h"
+
+namespace content {
+
+EmbeddedWorkerInstance::EmbeddedWorkerInstance(
+    EmbeddedWorkerRegistry* registry,
+    int embedded_worker_id)
+    : registry_(registry),
+      embedded_worker_id_(embedded_worker_id),
+      status_(STOPPED),
+      process_id_(-1),
+      thread_id_(-1) {
+}
+
+EmbeddedWorkerInstance::~EmbeddedWorkerInstance() {
+  DCHECK(status_ == STOPPED);
+  registry_->RemoveWorker(embedded_worker_id_);
+}
+
+void EmbeddedWorkerInstance::Start(
+    int64 service_worker_version_id,
+    const GURL& script_url) {
+  DCHECK(status_ == STOPPED);
+  process_id_ = ChooseProcess();
+  status_ = STARTING;
+  bool success = registry_->StartWorker(
+      process_id_,
+      embedded_worker_id_,
+      service_worker_version_id,
+      script_url);
+  if (!success)
+    OnStopped();
+}
+
+void EmbeddedWorkerInstance::Stop() {
+  DCHECK(status_ == STARTING || status_ == RUNNING);
+  registry_->StopWorker(process_id_, embedded_worker_id_);

[alecflett, 2013/12/05 05:18:42]

set status to STOPPING?

[kinuko, 2013/12/09 14:07:42]

Yup, done.

+}
+
+void EmbeddedWorkerInstance::OnStarted(int thread_id) {
+  DCHECK(status_ == STARTING);
+  status_ = RUNNING;
+  thread_id_ = thread_id;
+}
+
+void EmbeddedWorkerInstance::OnStopped() {
+  status_ = STOPPED;

[alecflett, 2013/12/05 05:18:42]

DCHECK(status_ == STOPPING)?

[kinuko, 2013/12/09 14:07:42]

This could also happen in STARTING or RUNNING (i.e. not only by Stop()), when
the worker script has failed to load or the worker closed itself (the latter
sounds weird in service worker context but it looks it's possible as far as it
derives from WorkerGlobalScope)

+  process_id_ = -1;
+  thread_id_ = -1;
+}
+
+void EmbeddedWorkerInstance::AddProcessReference(int process_id) {
+  ProcessRefMap::iterator found = process_refs_.find(process_id);
+  if (found == process_refs_.end())
+    found = process_refs_.insert(std::make_pair(process_id, 0)).first;
+  ++found->second;
+}
+
+void EmbeddedWorkerInstance::ReleaseProcessReference(int process_id) {
+  ProcessRefMap::iterator found = process_refs_.find(process_id);
+  if (found == process_refs_.end()) {
+    NOTREACHED() << "Releasing unknown process ref " << process_id;
+    return;
+  }
+  if (--found->second == 0)
+    process_refs_.erase(found);
+}
+
+int EmbeddedWorkerInstance::ChooseProcess() {
+  // Naive implementation; chooses a process which has the biggest number of
+  // associated providers (so that hopefully likely live longer).
+  ProcessRefMap::iterator max_ref_iter = process_refs_.end();
+  for (ProcessRefMap::iterator iter = process_refs_.begin();
+       iter != process_refs_.end(); ++iter) {
+    if (max_ref_iter == process_refs_.end() ||
+        max_ref_iter->second < iter->second)
+      max_ref_iter = iter;
+  }
+  DCHECK(max_ref_iter != process_refs_.end());

[alecflett, 2013/12/05 05:18:42]

Won't this be true if there are no entries in process_refs_ ? i.e. if the map is
empty, then max_ref_iter never gets reset to a valid process?

(Or is is guaranteed that AddProcessReference is called first? if so, perhaps
also DCHECK(ProcessRefMap.size() > 0) at the start of the function?

[kinuko, 2013/12/09 14:07:42]

Currently this instance code has some assumptions like: the caller (likely the
ServiceWorkerVersion) doesn't call Start() or Stop() in a wrong state, or
doesn't call Start() when no corresponding ProviderHost's around.

The latter assumption might not be obvious though, so I've made this method and
Start() fail when no process's available.

+  return max_ref_iter->first;
+}
+
+}  // namespace content