Create base::WorkerPoolJob. Use it for HostResolverImpl and DirectoryLister.

net/base/host_resolver_impl.cc

Index: net/base/host_resolver_impl.cc
diff --git a/net/base/host_resolver_impl.cc b/net/base/host_resolver_impl.cc
index b53ec6d3ccd5caeba55953ec6c195d117a396b07..b28cb23a00e279958ab69a02c569ea868014fa2d 100644
--- a/net/base/host_resolver_impl.cc
+++ b/net/base/host_resolver_impl.cc
@@ -27,7 +27,7 @@
 #include "base/time.h"
 #include "base/utf_string_conversions.h"
 #include "base/values.h"
-#include "base/worker_pool.h"
+#include "base/worker_pool_job.h"
 #include "net/base/address_list.h"
 #include "net/base/address_list_net_log_param.h"
 #include "net/base/host_port_pair.h"
@@ -338,8 +338,7 @@ class HostResolverImpl::Request {
 
 // This class represents a request to the worker pool for a "getaddrinfo()"
 // call.
-class HostResolverImpl::Job
-    : public base::RefCountedThreadSafe<HostResolverImpl::Job> {
+class HostResolverImpl::Job : public base::WorkerPoolJob {
  public:
   Job(int id,
       HostResolverImpl* resolver,
@@ -349,7 +348,6 @@ class HostResolverImpl::Job
      : id_(id),
        key_(key),
        resolver_(resolver),
-       origin_loop_(MessageLoop::current()),
        resolver_proc_(resolver->effective_resolver_proc()),
        error_(OK),
        os_error_(0),
@@ -381,33 +379,17 @@ class HostResolverImpl::Job
   void Start() {
     start_time_ = base::TimeTicks::Now();
 
-    // Dispatch the job to a worker thread.
-    if (!WorkerPool::PostTask(FROM_HERE,
-            NewRunnableMethod(this, &Job::DoLookup), true)) {
-      NOTREACHED();
-
-      // Since we could be running within Resolve() right now, we can't just
-      // call OnLookupComplete().  Instead we must wait until Resolve() has
-      // returned (IO_PENDING).
-      error_ = ERR_UNEXPECTED;
-      MessageLoop::current()->PostTask(
-          FROM_HERE, NewRunnableMethod(this, &Job::OnLookupComplete));
-    }
+    StartJob();
   }
 
   // Cancels the current job. Callable from origin thread.
   void Cancel() {
-    net_log_.AddEvent(NetLog::TYPE_CANCELLED, NULL);
+    if (canceled())
+      return;
 
-    HostResolver* resolver = resolver_;
-    resolver_ = NULL;
+    CancelJob();
 
-    // Mark the job as cancelled, so when worker thread completes it will
-    // not try to post completion to origin loop.
-    {
-      AutoLock locked(origin_loop_lock_);
-      origin_loop_ = NULL;
-    }
+    net_log_.AddEvent(NetLog::TYPE_CANCELLED, NULL);
 
     // End here to prevent issues when a Job outlives the HostResolver that
     // spawned it.
@@ -419,16 +401,11 @@ class HostResolverImpl::Job
          it != requests_.end(); ++it) {
       HostResolverImpl::Request* req = *it;
       if (!req->was_cancelled())
-        resolver->CancelRequest(req);
+        resolver_->CancelRequest(req);
     }
   }
 
   // Called from origin thread.
-  bool was_cancelled() const {
-    return resolver_ == NULL;
-  }
-
-  // Called from origin thread.
   const Key& key() const {
     return key_;
   }
@@ -448,7 +425,6 @@ class HostResolverImpl::Job
 
   // Returns the first request attached to the job.
   const Request* initial_request() const {
-    DCHECK_EQ(origin_loop_, MessageLoop::current());
     DCHECK(!requests_.empty());
     return requests_[0];
   }
@@ -458,6 +434,9 @@ class HostResolverImpl::Job
     return key_ == resolver_->GetEffectiveKeyForRequest(req_info);
   }
 
+  // TODO(willchan): Eliminate the need for this.
+  using WorkerPoolJob::canceled;
+
  private:
   friend class base::RefCountedThreadSafe<HostResolverImpl::Job>;
 
@@ -470,7 +449,7 @@ class HostResolverImpl::Job
   // wait for it to finish, so we must be very careful here about using other
   // objects (like MessageLoops, Singletons, etc). During shutdown these objects
   // may no longer exist.
-  void DoLookup() {
+  virtual void RunJob() {
     // Running on the worker thread
     error_ = ResolveAddrInfo(resolver_proc_,
                              key_.hostname,
@@ -478,24 +457,10 @@ class HostResolverImpl::Job
                              key_.host_resolver_flags,
                              &results_,
                              &os_error_);
-
-    // The origin loop could go away while we are trying to post to it, so we
-    // need to call its PostTask method inside a lock.  See ~HostResolver.
-    {
-      AutoLock locked(origin_loop_lock_);
-      if (origin_loop_) {
-        origin_loop_->PostTask(FROM_HERE,
-                               NewRunnableMethod(this, &Job::OnLookupComplete));
-      }
-    }
   }
 
-  // Callback for when DoLookup() completes (runs on origin thread).
-  void OnLookupComplete() {
-    // Should be running on origin loop.
-    // TODO(eroman): this is being hit by URLRequestTest.CancelTest*,
-    // because MessageLoop::current() == NULL.
-    //DCHECK_EQ(origin_loop_, MessageLoop::current());
+  // Callback for when RunJob() completes (runs on origin thread).
+  virtual void CompleteJob() {
     DCHECK(error_ || results_.head());
 
     // Ideally the following code would be part of host_resolver_proc.cc,
@@ -506,9 +471,6 @@ class HostResolverImpl::Job
 
     RecordPerformanceHistograms();
 
-    if (was_cancelled())
-      return;
-
     scoped_refptr<NetLog::EventParameters> params;
     if (error_ != OK) {
       params = new HostResolveFailedParams(error_, os_error_);
@@ -590,8 +552,6 @@ class HostResolverImpl::Job
     }
   }
 
-
-
   // Immutable. Can be read from either thread,
   const int id_;
 
@@ -602,10 +562,6 @@ class HostResolverImpl::Job
   HostResolverImpl* resolver_;
   RequestsList requests_;  // The requests waiting on this job.
 
-  // Used to post ourselves onto the origin thread.
-  Lock origin_loop_lock_;
-  MessageLoop* origin_loop_;
-
   // Hold an owning reference to the HostResolverProc that we are going to use.
   // This may not be the current resolver procedure by the time we call
   // ResolveAddrInfo, but that's OK... we'll use it anyways, and the owning
@@ -636,36 +592,16 @@ class HostResolverImpl::Job
 
 // This class represents a request to the worker pool for a "probe for IPv6
 // support" call.
-class HostResolverImpl::IPv6ProbeJob
-    : public base::RefCountedThreadSafe<HostResolverImpl::IPv6ProbeJob> {
+class HostResolverImpl::IPv6ProbeJob : public base::WorkerPoolJob {
  public:
   explicit IPv6ProbeJob(HostResolverImpl* resolver)
       : resolver_(resolver),
-        origin_loop_(MessageLoop::current()) {
-    DCHECK(!was_cancelled());
+        address_family_(ADDRESS_FAMILY_UNSPECIFIED) {
+    DCHECK(resolver_);
   }
 
-  void Start() {
-    if (was_cancelled())
-      return;
-    DCHECK(IsOnOriginThread());
-    const bool kIsSlow = true;
-    WorkerPool::PostTask(
-        FROM_HERE, NewRunnableMethod(this, &IPv6ProbeJob::DoProbe), kIsSlow);
-  }
-
-  // Cancels the current job.
-  void Cancel() {
-    if (was_cancelled())
-      return;
-    DCHECK(IsOnOriginThread());
-    resolver_ = NULL;  // Read/write ONLY on origin thread.
-    {
-      AutoLock locked(origin_loop_lock_);
-      // Origin loop may be destroyed before we can use it!
-      origin_loop_ = NULL;  // Write ONLY on origin thread.
-    }
-  }
+  void Start() { StartJob(); }
+  void Cancel() { CancelJob(); }
 
  private:
   friend class base::RefCountedThreadSafe<HostResolverImpl::IPv6ProbeJob>;
@@ -673,57 +609,22 @@ class HostResolverImpl::IPv6ProbeJob
   ~IPv6ProbeJob() {
   }
 
-  // Should be run on |orgin_thread_|, but that may not be well defined now.
-  bool was_cancelled() const {
-    if (!resolver_ || !origin_loop_) {
-      DCHECK(!resolver_);
-      DCHECK(!origin_loop_);
-      return true;
-    }
-    return false;
-  }
-
   // Run on worker thread.
-  void DoProbe() {
+  virtual void RunJob() {
     // Do actual testing on this thread, as it takes 40-100ms.
-    AddressFamily family = IPv6Supported() ? ADDRESS_FAMILY_UNSPECIFIED
-                                           : ADDRESS_FAMILY_IPV4;
-
-    Task* reply = NewRunnableMethod(this, &IPv6ProbeJob::OnProbeComplete,
-                                    family);
-
-    // The origin loop could go away while we are trying to post to it, so we
-    // need to call its PostTask method inside a lock.  See ~HostResolver.
-    {
-      AutoLock locked(origin_loop_lock_);
-      if (origin_loop_) {
-        origin_loop_->PostTask(FROM_HERE, reply);
-        return;
-      }
-    }
-
-    // We didn't post, so delete the reply.
-    delete reply;
+    address_family_ = IPv6Supported() ? ADDRESS_FAMILY_UNSPECIFIED
+                                      : ADDRESS_FAMILY_IPV4;
   }
 
   // Callback for when DoProbe() completes (runs on origin thread).
-  void OnProbeComplete(AddressFamily address_family) {
-    if (was_cancelled())
-      return;
-    DCHECK(IsOnOriginThread());
-    resolver_->IPv6ProbeSetDefaultAddressFamily(address_family);
-  }
-
-  bool IsOnOriginThread() const {
-    return !MessageLoop::current() || origin_loop_ == MessageLoop::current();
+  virtual void CompleteJob() {
+    resolver_->IPv6ProbeSetDefaultAddressFamily(address_family_);
   }
 
   // Used/set only on origin thread.
-  HostResolverImpl* resolver_;
+  HostResolverImpl* const resolver_;
 
-  // Used to post ourselves onto the origin thread.
-  Lock origin_loop_lock_;
-  MessageLoop* origin_loop_;
+  AddressFamily address_family_;
 
   DISALLOW_COPY_AND_ASSIGN(IPv6ProbeJob);
 };
@@ -1230,7 +1131,7 @@ void HostResolverImpl::OnJobCompleteInternal(
 
       // Check if the job was cancelled as a result of running the callback.
       // (Meaning that |this| was deleted).
-      if (job->was_cancelled())
+      if (job->canceled())
         return;
     }
   }