Update from https://crrev.com/307330

net/base/directory_lister.cc

 // Copyright (c) 2012 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 "net/base/directory_lister.h"
 
 #include <algorithm>
-#include <vector>
 
 #include "base/bind.h"
 #include "base/files/file_enumerator.h"
 #include "base/files/file_util.h"
 #include "base/i18n/file_util_icu.h"
+#include "base/logging.h"
 #include "base/message_loop/message_loop.h"
 #include "base/threading/thread_restrictions.h"
 #include "base/threading/worker_pool.h"
 #include "net/base/net_errors.h"
 
 namespace net {
 
 namespace {
 
 bool IsDotDot(const base::FilePath& path) {
@@ skipping 42 matching lines @@
 // Static.
 bool CompareFullPath(const DirectoryLister::DirectoryListerData& a,
                      const DirectoryLister::DirectoryListerData& b) {
   return base::i18n::LocaleAwareCompareFilenames(a.path, b.path);
 }
 
 void SortData(std::vector<DirectoryLister::DirectoryListerData>* data,
               DirectoryLister::SortType sort_type) {
   // Sort the results. See the TODO below (this sort should be removed and we
   // should do it from JS).
-  if (sort_type == DirectoryLister::DATE)
+  if (sort_type == DirectoryLister::DATE) {
     std::sort(data->begin(), data->end(), CompareDate);
-  else if (sort_type == DirectoryLister::FULL_PATH)
+  } else if (sort_type == DirectoryLister::FULL_PATH) {
     std::sort(data->begin(), data->end(), CompareFullPath);
-  else if (sort_type == DirectoryLister::ALPHA_DIRS_FIRST)
+  } else if (sort_type == DirectoryLister::ALPHA_DIRS_FIRST) {
     std::sort(data->begin(), data->end(), CompareAlphaDirsFirst);
-  else
+  } else {
     DCHECK_EQ(DirectoryLister::NO_SORT, sort_type);
+  }
 }
 
 }  // namespace
 
 DirectoryLister::DirectoryLister(const base::FilePath& dir,
                                  DirectoryListerDelegate* delegate)
-    : core_(new Core(dir, false, ALPHA_DIRS_FIRST, this)),
-      delegate_(delegate) {
+    : delegate_(delegate) {
+  core_ = new Core(dir, false, ALPHA_DIRS_FIRST, this);
   DCHECK(delegate_);
   DCHECK(!dir.value().empty());
 }
 
 DirectoryLister::DirectoryLister(const base::FilePath& dir,
                                  bool recursive,
                                  SortType sort,
                                  DirectoryListerDelegate* delegate)
-    : core_(new Core(dir, recursive, sort, this)),
-      delegate_(delegate) {
+    : delegate_(delegate) {
+  core_ = new Core(dir, recursive, sort, this);
   DCHECK(delegate_);
   DCHECK(!dir.value().empty());
 }
 
 DirectoryLister::~DirectoryLister() {
   Cancel();
 }
 
 bool DirectoryLister::Start() {
-  return core_->Start();
+  return base::WorkerPool::PostTask(
+      FROM_HERE,
+      base::Bind(&Core::Start, core_),
+      true);
 }
 
 void DirectoryLister::Cancel() {
-  return core_->Cancel();
+  core_->CancelOnOriginThread();
 }
 
 DirectoryLister::Core::Core(const base::FilePath& dir,
                             bool recursive,
                             SortType sort,
                             DirectoryLister* lister)
     : dir_(dir),
       recursive_(recursive),
       sort_(sort),
-      lister_(lister) {
+      origin_loop_(base::MessageLoopProxy::current()),
+      lister_(lister),
+      cancelled_(0) {
   DCHECK(lister_);
 }
 
 DirectoryLister::Core::~Core() {}
 
-bool DirectoryLister::Core::Start() {
-  origin_loop_ = base::MessageLoopProxy::current();
+void DirectoryLister::Core::CancelOnOriginThread() {
+  DCHECK(origin_loop_->BelongsToCurrentThread());
 
-  return base::WorkerPool::PostTask(
-      FROM_HERE, base::Bind(&Core::StartInternal, this), true);
+  base::subtle::NoBarrier_Store(&cancelled_, 1);
+  // Core must not call into |lister_| after cancellation, as the |lister_| may
+  // have been destroyed. Setting |lister_| to NULL ensures any such access will
+  // cause a crash.
+  lister_ = nullptr;
 }
 
-void DirectoryLister::Core::Cancel() {
-  lister_ = NULL;
-}
-
-void DirectoryLister::Core::StartInternal() {
+void DirectoryLister::Core::Start() {
+  scoped_ptr<DirectoryList> directory_list(new DirectoryList());
 
   if (!base::DirectoryExists(dir_)) {
     origin_loop_->PostTask(
         FROM_HERE,
-        base::Bind(&DirectoryLister::Core::OnDone, this, ERR_FILE_NOT_FOUND));
+        base::Bind(&Core::DoneOnOriginThread, this,
+                   base::Passed(directory_list.Pass()), ERR_FILE_NOT_FOUND));
     return;
   }
 
   int types = base::FileEnumerator::FILES | base::FileEnumerator::DIRECTORIES;
   if (!recursive_)
     types |= base::FileEnumerator::INCLUDE_DOT_DOT;
 
   base::FileEnumerator file_enum(dir_, recursive_, types);
 
   base::FilePath path;
-  std::vector<DirectoryListerData> file_data;
-  while (lister_ && !(path = file_enum.Next()).empty()) {
+  while (!(path = file_enum.Next()).empty()) {
+    // Abort on cancellation. This is purely for performance reasons.
+    // Correctness guarantees are made by checks in DoneOnOriginThread.
+    if (IsCancelled())
+      return;
+
     DirectoryListerData data;
     data.info = file_enum.GetInfo();
     data.path = path;
-    file_data.push_back(data);
+    directory_list->push_back(data);
 
     /* TODO(brettw) bug 24107: It would be nice to send incremental updates.
        We gather them all so they can be sorted, but eventually the sorting
        should be done from JS to give more flexibility in the page. When we do
        that, we can uncomment this to send incremental updates to the page.
 
     const int kFilesPerEvent = 8;
     if (file_data.size() < kFilesPerEvent)
       continue;
 
     origin_loop_->PostTask(
         FROM_HERE,
         base::Bind(&DirectoryLister::Core::SendData, file_data));
     file_data.clear();
     */
   }
 
-  SortData(&file_data, sort_);
-  origin_loop_->PostTask(
-      FROM_HERE,
-      base::Bind(&DirectoryLister::Core::SendData, this, file_data));
+  SortData(directory_list.get(), sort_);
 
   origin_loop_->PostTask(
       FROM_HERE,
-      base::Bind(&DirectoryLister::Core::OnDone, this, OK));
+      base::Bind(&Core::DoneOnOriginThread, this,
+                 base::Passed(directory_list.Pass()), OK));
 }
 
-void DirectoryLister::Core::SendData(
-    const std::vector<DirectoryLister::DirectoryListerData>& data) {
-  DCHECK(origin_loop_->BelongsToCurrentThread());
-  // We need to check for cancellation (indicated by NULL'ing of |lister_|)
-  // which can happen during each callback.
-  for (size_t i = 0; lister_ && i < data.size(); ++i)
-    lister_->OnReceivedData(data[i]);
+bool DirectoryLister::Core::IsCancelled() const {
+  return !!base::subtle::NoBarrier_Load(&cancelled_);
 }
 
-void DirectoryLister::Core::OnDone(int error) {
+void DirectoryLister::Core::DoneOnOriginThread(
+    scoped_ptr<DirectoryList> directory_list, int error) const {
   DCHECK(origin_loop_->BelongsToCurrentThread());
-  if (lister_)
-    lister_->OnDone(error);
+
+  // Need to check if the operation was before first callback.
+  if (IsCancelled())
+    return;
+
+  for (const auto& lister_data : *directory_list) {
+    lister_->OnListFile(lister_data);
+    // Need to check if the operation was cancelled during the callback.
+    if (IsCancelled())
+      return;
+  }
+  lister_->OnListDone(error);
 }
 
-void DirectoryLister::OnReceivedData(const DirectoryListerData& data) {
+void DirectoryLister::OnListFile(const DirectoryListerData& data) {
   delegate_->OnListFile(data);
 }
 
-void DirectoryLister::OnDone(int error) {
+void DirectoryLister::OnListDone(int error) {
   delegate_->OnListDone(error);
 }
 
 }  // namespace net