src/components/dom_distiller/core/task_tracker.cc

   1 // Copyright 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "components/dom_distiller/core/task_tracker.h"
   6
   7 #include "base/message_loop/message_loop.h"
   8 #include "components/dom_distiller/core/proto/distilled_article.pb.h"
   9 #include "components/dom_distiller/core/proto/distilled_page.pb.h"
  10
  11 namespace dom_distiller {
  12
  13 ViewerHandle::ViewerHandle(CancelCallback callback)
  14     : cancel_callback_(callback) {}
  15
  16 ViewerHandle::~ViewerHandle() {
  17   if (!cancel_callback_.is_null()) {
  18     cancel_callback_.Run();
  19   }
  20 }
  21
  22 TaskTracker::TaskTracker(const ArticleEntry& entry, CancelCallback callback)
  23     : cancel_callback_(callback),
  24       entry_(entry),
  25       distilled_article_(),
  26       distillation_complete_(false),
  27       weak_ptr_factory_(this) {}
  28
  29 TaskTracker::~TaskTracker() { DCHECK(viewers_.empty()); }
  30
  31 void TaskTracker::StartDistiller(DistillerFactory* factory) {
  32   if (distiller_) {
  33     return;
  34   }
  35   if (entry_.pages_size() == 0) {
  36     return;
  37   }
  38
  39   GURL url(entry_.pages(0).url());
  40   DCHECK(url.is_valid());
  41
  42   distiller_ = factory->CreateDistiller();
  43   distiller_->DistillPage(url,
  44                           base::Bind(&TaskTracker::OnDistilledDataReady,
  45                                      weak_ptr_factory_.GetWeakPtr()));
  46 }
  47
  48 void TaskTracker::StartBlobFetcher() {
  49   // TODO(cjhopman): There needs to be some local storage for the distilled
  50   // blob. When that happens, this should start some task to fetch the blob for
  51   // |entry_| and asynchronously notify |this| when it is done.
  52 }
  53
  54 void TaskTracker::AddSaveCallback(const SaveCallback& callback) {
  55   DCHECK(!callback.is_null());
  56   save_callbacks_.push_back(callback);
  57   if (distillation_complete_) {
  58     // Distillation for this task has already completed, and so it can be
  59     // immediately saved.
  60     ScheduleSaveCallbacks(true);
  61   }
  62 }
  63
  64 scoped_ptr<ViewerHandle> TaskTracker::AddViewer(ViewRequestDelegate* delegate) {
  65   viewers_.push_back(delegate);
  66   if (distillation_complete_) {
  67     // Distillation for this task has already completed, and so the delegate can
  68     // be immediately told of the result.
  69     base::MessageLoop::current()->PostTask(
  70         FROM_HERE,
  71         base::Bind(&TaskTracker::NotifyViewer,
  72                    weak_ptr_factory_.GetWeakPtr(),
  73                    delegate));
  74   }
  75   return scoped_ptr<ViewerHandle>(new ViewerHandle(base::Bind(
  76       &TaskTracker::RemoveViewer, weak_ptr_factory_.GetWeakPtr(), delegate)));
  77 }
  78
  79 const std::string& TaskTracker::GetEntryId() const { return entry_.entry_id(); }
  80
  81 bool TaskTracker::HasEntryId(const std::string& entry_id) const {
  82   return entry_.entry_id() == entry_id;
  83 }
  84
  85 bool TaskTracker::HasUrl(const GURL& url) const {
  86   for (int i = 0; i < entry_.pages_size(); ++i) {
  87     if (entry_.pages(i).url() == url.spec()) {
  88       return true;
  89     }
  90   }
  91   return false;
  92 }
  93
  94 void TaskTracker::RemoveViewer(ViewRequestDelegate* delegate) {
  95   viewers_.erase(std::remove(viewers_.begin(), viewers_.end(), delegate));
  96   if (viewers_.empty()) {
  97     MaybeCancel();
  98   }
  99 }
 100
 101 void TaskTracker::MaybeCancel() {
 102   if (!save_callbacks_.empty() || !viewers_.empty()) {
 103     // There's still work to be done.
 104     return;
 105   }
 106
 107   // The cancel callback should not delete this. To ensure that it doesn't, grab
 108   // a weak pointer and check that it has not been invalidated.
 109   base::WeakPtr<TaskTracker> self(weak_ptr_factory_.GetWeakPtr());
 110   cancel_callback_.Run(this);
 111   DCHECK(self);
 112 }
 113
 114 void TaskTracker::CancelSaveCallbacks() { ScheduleSaveCallbacks(false); }
 115
 116 void TaskTracker::ScheduleSaveCallbacks(bool distillation_succeeded) {
 117   base::MessageLoop::current()->PostTask(
 118       FROM_HERE,
 119       base::Bind(&TaskTracker::DoSaveCallbacks,
 120                  weak_ptr_factory_.GetWeakPtr(),
 121                  distillation_succeeded));
 122 }
 123
 124 void TaskTracker::DoSaveCallbacks(bool distillation_succeeded) {
 125   if (!save_callbacks_.empty()) {
 126     for (size_t i = 0; i < save_callbacks_.size(); ++i) {
 127       DCHECK(!save_callbacks_[i].is_null());
 128       save_callbacks_[i].Run(
 129           entry_, distilled_article_.get(), distillation_succeeded);
 130     }
 131
 132     save_callbacks_.clear();
 133     MaybeCancel();
 134   }
 135 }
 136
 137 void TaskTracker::NotifyViewer(ViewRequestDelegate* delegate) {
 138   DCHECK(distillation_complete_);
 139   delegate->OnArticleReady(distilled_article_.get());
 140 }
 141
 142 void TaskTracker::OnDistilledDataReady(
 143     scoped_ptr<DistilledArticleProto> distilled_article) {
 144   distilled_article_ = distilled_article.Pass();
 145   bool distillation_successful = false;
 146   if (distilled_article_->pages_size() > 0) {
 147     distillation_successful = true;
 148     entry_.set_title(distilled_article_->title());
 149     // Reset the pages.
 150     entry_.clear_pages();
 151     for (int i = 0; i < distilled_article_->pages_size(); ++i) {
 152       sync_pb::ArticlePage* page = entry_.add_pages();
 153       page->set_url(distilled_article_->pages(i).url());
 154     }
 155   }
 156
 157   distillation_complete_ = true;
 158
 159   for (size_t i = 0; i < viewers_.size(); ++i) {
 160     NotifyViewer(viewers_[i]);
 161   }
 162
 163   // Already inside a callback run SaveCallbacks directly.
 164   DoSaveCallbacks(distillation_successful);
 165 }
 166
 167 }  // namespace dom_distiller