ServiceWorker: Move worker candidate process knowledge to ServiceWorkerProcessManager.

content/browser/service_worker/service_worker_process_manager.h

 // Copyright 2014 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.
 
 #ifndef CONTENT_BROWSER_SERVICE_WORKER_SERVICE_WORKER_PROCESS_MANAGER_H_
 #define CONTENT_BROWSER_SERVICE_WORKER_SERVICE_WORKER_PROCESS_MANAGER_H_
 
 #include <map>
 #include <vector>
 
 #include "base/callback.h"
+#include "base/gtest_prod_util.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
 #include "content/common/service_worker/service_worker_status_code.h"
+#include "content/public/browser/render_process_host_observer.h"
 
 class GURL;
 
 namespace content {
 
 class BrowserContext;
 class SiteInstance;
 
 // Interacts with the UI thread to keep RenderProcessHosts alive while the
-// ServiceWorker system is using them. Each instance of
-// ServiceWorkerProcessManager is destroyed on the UI thread shortly after its
-// ServiceWorkerContextWrapper is destroyed.
-class CONTENT_EXPORT ServiceWorkerProcessManager {
+// ServiceWorker system is using them. It also tracks candidate processes
+// for each scope. Each instance of ServiceWorkerProcessManager is destroyed
+// on the UI thread shortly after its ServiceWorkerContextWrapper is destroyed.
+class CONTENT_EXPORT ServiceWorkerProcessManager
+    : public RenderProcessHostObserver {
  public:
   // |*this| must be owned by a ServiceWorkerContextWrapper in a
   // StoragePartition within |browser_context|.
   explicit ServiceWorkerProcessManager(BrowserContext* browser_context);
 
   // Shutdown must be called before the ProcessManager is destroyed.
-  ~ServiceWorkerProcessManager();
+  virtual ~ServiceWorkerProcessManager();
 
   // Synchronously prevents new processes from being allocated.
   // TODO(jyasskin): Drop references to RenderProcessHosts too.
   void Shutdown();
 
   // Returns a reference to a running process suitable for starting the Service
-  // Worker at |script_url|. Processes in |process_ids| will be checked in order
-  // for existence, and if none exist, then a new process will be created. Posts
-  // |callback| to the IO thread to indicate whether creation succeeded and the
-  // process ID that has a new reference.
+  // Worker at |script_url|. Posts |callback| to the IO thread to indicate
+  // whether creation succeeded and the process ID that has a new reference.
   //
   // Allocation can fail with SERVICE_WORKER_ERROR_START_WORKER_FAILED if
   // RenderProcessHost::Init fails.
   void AllocateWorkerProcess(
       int embedded_worker_id,
-      const std::vector<int>& process_ids,
+      const GURL& scope,
       const GURL& script_url,
       const base::Callback<void(ServiceWorkerStatusCode, int process_id)>&
           callback);
 
   // Drops a reference to a process that was running a Service Worker, and its
   // SiteInstance.  This must match a call to AllocateWorkerProcess.
   void ReleaseWorkerProcess(int embedded_worker_id);
 
   // Sets a single process ID that will be used for all embedded workers.  This
   // bypasses the work of creating a process and managing its worker refcount so
   // that unittests can run without a BrowserContext.  The test is in charge of
   // making sure this is only called on the same thread as runs the UI message
   // loop.
   void SetProcessIdForTest(int process_id) {
     process_id_for_test_ = process_id;
   }
 
+  // Adds/removes process reference for the |scope|, the process with highest
+  // score will be chosen to start worker. The pending processes will be added

[Jeffrey Yasskin, 2014/08/19 23:42:24]

It's not clear what a "score" or "priority" is here.

[xiang, 2014/08/29 07:49:40]

Done.

+  // with lowest priority(0).
+  void AddScopePendingProcesses(const GURL& scope,
+                                const std::vector<int>& pending_processes);

[kinuko, 2014/08/12 15:27:07]

This method and where we call it feels a bit sketchy to me (not your fault,
original design around pending_process_ids_ was also a bit awkward).  It looks
like when/where we want to call these methods are not necessarily in the
SWVersion code, but similar to when we associate SWPH to SW registrations (i.e.
1. when an in-scope document is loaded in SWControlleeRequestHandler, and 2.
when a new registration is about to be installed in SWRegisterJob)?  If so we
might be able to simply call these methods in SWPH::{Un,}assocRegistration and
remove Pending version of method, to simplify the model?

[Jeffrey Yasskin, 2014/08/19 23:42:24]

+1 to removing "pending" processes, if possible. 

[xiang, 2014/08/29 07:49:40]

Done.

+  void AddScopeProcessReference(const GURL& scope, int process_id);
+  void RemoveScopeProcessReference(const GURL& scope, int process_id);
+
+  // Returns true if the |scope| has at least one process to run.
+  bool ScopeHasProcessToRun(const GURL& scope) const;
+
+  // RenderProcessHostObserver overrides:
+  virtual void RenderProcessHostDestroyed(RenderProcessHost* host) OVERRIDE;
+
  private:
+  FRIEND_TEST_ALL_PREFIXES(ServiceWorkerProcessManagerTest, SortProcess);
+
   // Information about the process for an EmbeddedWorkerInstance.
   struct ProcessInfo {
     explicit ProcessInfo(const scoped_refptr<SiteInstance>& site_instance);
     explicit ProcessInfo(int process_id);
     ~ProcessInfo();
 
     // Stores the SiteInstance the Worker lives inside. This needs to outlive
     // the instance's use of its RPH to uphold assumptions in the
     // ContentBrowserClient interface.
     scoped_refptr<SiteInstance> site_instance;
 
     // In case the process was allocated without using a SiteInstance, we need
     // to store a process ID to decrement a worker reference on shutdown.
     // TODO(jyasskin): Implement http://crbug.com/372045 or thread a frame_id in
     // so all processes can be allocated with a SiteInstance.
     int process_id;
   };
 
+  typedef std::map<int, int> ProcessRefMap;

[Jeffrey Yasskin, 2014/08/19 23:42:24]

Always document what an "int" means.

[xiang, 2014/08/29 07:49:39]

Done.

+  typedef std::map<const GURL, ProcessRefMap> ScopeProcessRefMap;
+
+  // Returns a process vector sorted by the reference count for the |scope|.
+  std::vector<int> SortProcessesForScope(const GURL& scope) const;
+
   // These fields are only accessed on the UI thread.
   BrowserContext* browser_context_;
 
   // Maps the ID of a running EmbeddedWorkerInstance to information about the
   // process it's running inside. Since the Instances themselves live on the IO
   // thread, this can be slightly out of date:
   //  * instance_info_ is populated while an Instance is STARTING and before
   //    it's RUNNING.
   //  * instance_info_ is depopulated in a message sent as the Instance becomes
   //    STOPPED.
   std::map<int, ProcessInfo> instance_info_;
 
   // In unit tests, this will be returned as the process for all
   // EmbeddedWorkerInstances.
   int process_id_for_test_;
 
+  // Candidate process info for each scope, should be accessed on the UI thread.
+  ScopeProcessRefMap scope_processes_;
+
   // Used to double-check that we don't access *this after it's destroyed.
   base::WeakPtrFactory<ServiceWorkerProcessManager> weak_this_factory_;
   const base::WeakPtr<ServiceWorkerProcessManager> weak_this_;
 };
 
 }  // namespace content
 
 namespace base {
 // Specialized to post the deletion to the UI thread.
 template <>
 struct CONTENT_EXPORT DefaultDeleter<content::ServiceWorkerProcessManager> {
   void operator()(content::ServiceWorkerProcessManager* ptr) const;
 };
 }  // namespace base
 
 #endif  // CONTENT_BROWSER_SERVICE_WORKER_SERVICE_WORKER_PROCESS_MANAGER_H_