Save favicon during reading list distillation

ios/chrome/browser/dom_distiller/web_state_pool_impl.mm

+// Copyright 2016 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 "ios/chrome/browser/dom_distiller/web_state_pool_impl.h"
+
+#include "components/favicon/ios/web_favicon_driver.h"
+#include "components/keyed_service/core/service_access_type.h"
+#include "ios/chrome/browser/bookmarks/bookmark_model_factory.h"
+#include "ios/chrome/browser/browser_state/chrome_browser_state.h"
+#include "ios/chrome/browser/favicon/favicon_service_factory.h"
+#include "ios/chrome/browser/history/history_service_factory.h"
+
+namespace {
+// Number of WebState in the pool.
+const int kMaxNumberOfWebState = 10;
+// Maximum delay before timeout.
+const int kMaxDelayFavicon = 10;
+// Number of second before the WebState is returned to the pool after the
+// reception of the favicon.
+const int kDelayFavicon = 1;
+}
+
+namespace dom_distiller {
+
+WebStatePoolImpl::WebStatePoolImpl(web::BrowserState* browser_state)
+    : browser_state_(browser_state),
+      unique_web_states_(kMaxNumberOfWebState),
+      web_states_(kMaxNumberOfWebState),
+      weak_ptr_factory_(this) {}
+WebStatePoolImpl::~WebStatePoolImpl() {}
+
+void WebStatePoolImpl::OnFaviconUpdated(
+    favicon::FaviconDriver* favicon_driver,
+    favicon::FaviconDriverObserver::NotificationIconType notification_icon_type,
+    const GURL& icon_url,
+    bool icon_url_changed,
+    const gfx::Image& image) {
+  dispatch_after(
+      dispatch_time(DISPATCH_TIME_NOW, (int64_t)(kDelayFavicon * NSEC_PER_SEC)),
+      dispatch_get_main_queue(), ^{
+        OnFaviconDownloaded(favicon_driver);
+      });
+}
+
+void WebStatePoolImpl::RequestWebState(WebStatePoolDelegate* delegate) {
+  int available_web_state = GetFirstWebStateAvailable();
+  if (available_web_state == -1) {
+    pending_delegates_.push_back(delegate);
+    return;
+  }
+
+  if (!web_states_[available_web_state]) {
+    // Lazily initialize WebState.
+    CreateWebState(available_web_state);
+  }
+  web::WebState* web_state = web_states_[available_web_state];
+  favicon::WebFaviconDriver* favicon_driver =
+      favicon::WebFaviconDriver::FromWebState(web_state);
+  favicon_web_state_.insert(
+      std::make_pair(favicon_driver, available_web_state));
+  registered_web_state_.insert(std::make_pair(web_state, available_web_state));
+
+  delegate->OnWebStateAvailable(web_state);
+}
+
+void WebStatePoolImpl::CreateWebState(int web_state_index) {
+  const web::WebState::CreateParams web_state_create_params(browser_state_);
+  std::unique_ptr<web::WebState> web_state_unique =
+      web::WebState::Create(web_state_create_params);
+  web::WebState* web_state = web_state_unique.get();
+  unique_web_states_[web_state_index] = std::move(web_state_unique);
+  web_states_[web_state_index] = web_state;
+
+  ios::ChromeBrowserState* original_browser_state =
+      ios::ChromeBrowserState::FromBrowserState(browser_state_);
+
+  favicon::WebFaviconDriver::CreateForWebState(
+      web_state,
+      ios::FaviconServiceFactory::GetForBrowserState(
+          original_browser_state, ServiceAccessType::EXPLICIT_ACCESS),
+      ios::HistoryServiceFactory::GetForBrowserState(
+          original_browser_state, ServiceAccessType::EXPLICIT_ACCESS),
+      ios::BookmarkModelFactory::GetForBrowserState(original_browser_state));
+  favicon::WebFaviconDriver* favicon_driver =
+      favicon::WebFaviconDriver::FromWebState(web_state);
+  favicon_driver->AddObserver(this);
+}
+
+void WebStatePoolImpl::ReturnWebState(web::WebState* web_state) {
+  favicon::WebFaviconDriver* favicon_driver =
+      favicon::WebFaviconDriver::FromWebState(web_state);
+
+  base::WeakPtr<WebStatePoolImpl> weak_this = weak_ptr_factory_.GetWeakPtr();
+  dispatch_after(dispatch_time(DISPATCH_TIME_NOW,
+                               (int64_t)(kMaxDelayFavicon * NSEC_PER_SEC)),
+                 dispatch_get_main_queue(), ^{
+                   WebStatePoolImpl* web_state_pool = weak_this.get();
+                   if (web_state_pool)
+                     web_state_pool->OnFaviconDownloaded(favicon_driver);
+                 });
+  registered_web_state_.erase(web_state);
+
+  // The favicon might have been downloaded before the WebState is returned.
+  while (GetFirstWebStateAvailable() != -1) {
+    RequestWebState(pending_delegates_.front());
+    pending_delegates_.pop_front();
+  }
+}
+
+void WebStatePoolImpl::OnFaviconDownloaded(favicon::FaviconDriver* driver) {
+  favicon_web_state_.erase(driver);
+
+  while (GetFirstWebStateAvailable() != -1) {
+    RequestWebState(pending_delegates_.front());
+    pending_delegates_.pop_front();
+  }
+}
+
+int WebStatePoolImpl::GetFirstWebStateAvailable() {
+  bool used_web_state[kMaxNumberOfWebState] = {false};
+
+  for (auto it = favicon_web_state_.begin(); it != favicon_web_state_.end();
+       it++) {
+    // Check the WebState used to download favicon.
+    used_web_state[it->second] = true;
+  }
+  for (auto it = registered_web_state_.begin();
+       it != registered_web_state_.end(); it++) {
+    // Check the WebState used by delegates.
+    used_web_state[it->second] = true;
+  }
+
+  for (int index = 0; index < kMaxNumberOfWebState; index++) {
+    if (!used_web_state[index]) {
+      return index;
+    }
+  }
+  return -1;
+}
+
+}  // namespace dom_distiller