Handle interface to prerenders.

chrome/browser/prerender/prerender_link_manager.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 "chrome/browser/prerender/prerender_link_manager.h"
 
 #include <limits>
 #include <queue>
 #include <utility>
 
 #include "chrome/browser/prerender/prerender_contents.h"
+#include "chrome/browser/prerender/prerender_handle.h"
 #include "chrome/browser/prerender/prerender_manager.h"
 #include "chrome/browser/prerender/prerender_manager_factory.h"
 #include "chrome/browser/profiles/profile.h"
 #include "content/public/browser/render_view_host.h"
 #include "content/public/browser/session_storage_namespace.h"
 #include "content/public/common/referrer.h"
 #include "googleurl/src/gurl.h"
 #include "googleurl/src/url_canon.h"
 #include "ui/gfx/size.h"
 
@@ skipping 21 matching lines @@
   DVLOG(3) << "... referrer url = " << referrer.url.spec()
            << ", size = (" << size.width() << ", " << size.height() << ")"
            << ", render_view_route_id = " << render_view_route_id;
 
   // TODO(gavinp): Add tests to ensure fragments work, then remove this fragment
   // clearing code.
   url_canon::Replacements<char> replacements;
   replacements.ClearRef();
   const GURL url = orig_url.ReplaceComponents(replacements);
 
-  if (!manager_->AddPrerenderFromLinkRelPrerender(
-          child_id, render_view_route_id, url, referrer, size)) {
+  base::WeakPtr<PrerenderHandle> prerender_handle =

[dominich, 2012/06/22 15:36:16]

and yet another smart pointer type required for the handle.

I think I'm repeating myself, and I'm sorry if I am, but I really feel that this
should be:

PrerenderHandle prerender_handle = manager_->AddPrerender...

and it should just work.

Maybe this means that somewhere there's a 

typedef scoped_refptr<PrerenderHandleImpl> PrerenderHandle;

or something, I'm not sure.

+      manager_->AddPrerenderFromLinkRelPrerender(child_id, render_view_route_id,
+                                                 url, referrer, size);
+  if (!prerender_handle)
     return false;
-  }
+
   const ChildAndPrerenderIdPair child_and_prerender_id(child_id, prerender_id);
-  DCHECK_EQ(0U, ids_to_url_map_.count(child_and_prerender_id));
-  ids_to_url_map_.insert(std::make_pair(child_and_prerender_id, url));
+  DCHECK_EQ(0U, ids_to_handle_map_.count(child_and_prerender_id));
+  ids_to_handle_map_.insert(std::make_pair(child_and_prerender_id,
+                                           prerender_handle));
   return true;
 }
 
 // TODO(gavinp): Once an observer interface is provided down to the WebKit
 // layer, we should add DCHECK_NE(0L, ids_to_url_map_.count(...)) to both
 // OnCancelPrerender and OnAbandonPrerender. We can't do this now, since
 // the WebKit layer isn't even aware if we didn't add the prerender to the map
 // in OnAddPrerender above.
 void PrerenderLinkManager::OnCancelPrerender(int child_id, int prerender_id) {
   DVLOG(2) << "OnCancelPrerender, child_id = " << child_id
            << ", prerender_id = " << prerender_id;
   const ChildAndPrerenderIdPair child_and_prerender_id(child_id, prerender_id);
-  IdPairToUrlMap::iterator id_url_iter =
-      ids_to_url_map_.find(child_and_prerender_id);
-  if (id_url_iter == ids_to_url_map_.end()) {
+  IdPairToPrerenderHandleMap::iterator id_handle_iter =
+      ids_to_handle_map_.find(child_and_prerender_id);
+  if (id_handle_iter == ids_to_handle_map_.end()) {
     DVLOG(5) << "... canceling a prerender that doesn't exist.";
     return;
   }
-  const GURL url = id_url_iter->second;
-  ids_to_url_map_.erase(id_url_iter);
-  manager_->MaybeCancelPrerender(url);
+  base::WeakPtr<PrerenderHandle>& prerender_handle = id_handle_iter->second;
+  if (prerender_handle)
+    prerender_handle->DecrementClientCount();
+  ids_to_handle_map_.erase(id_handle_iter);
 }
 
 void PrerenderLinkManager::OnAbandonPrerender(int child_id, int prerender_id) {
   DVLOG(2) << "OnAbandonPrerender, child_id = " << child_id
            << ", prerender_id = " << prerender_id;
   // TODO(gavinp,cbentzel): Implement reasonable behaviour for
   // navigation away from launcher.
   const ChildAndPrerenderIdPair child_and_prerender_id(child_id, prerender_id);
-  ids_to_url_map_.erase(child_and_prerender_id);
+  ids_to_handle_map_.erase(child_and_prerender_id);
 }
 
 void PrerenderLinkManager::OnChannelClosing(int child_id) {
   DVLOG(2) << "OnChannelClosing, child id = " << child_id;
   const ChildAndPrerenderIdPair child_and_minimum_prerender_id(
       child_id, std::numeric_limits<int>::min());
   const ChildAndPrerenderIdPair child_and_maximum_prerender_id(
       child_id, std::numeric_limits<int>::max());
   std::queue<int> prerender_ids_to_abandon;
-  for (IdPairToUrlMap::iterator
-           i = ids_to_url_map_.lower_bound(child_and_minimum_prerender_id),
-           e = ids_to_url_map_.upper_bound(child_and_maximum_prerender_id);
+  for (IdPairToPrerenderHandleMap::iterator
+           i = ids_to_handle_map_.lower_bound(child_and_minimum_prerender_id),
+           e = ids_to_handle_map_.upper_bound(child_and_maximum_prerender_id);
        i != e; ++i) {
     prerender_ids_to_abandon.push(i->first.second);
   }
   while (!prerender_ids_to_abandon.empty()) {
     DVLOG(4) << "---> abandon prerender_id = "
              << prerender_ids_to_abandon.front();
     OnAbandonPrerender(child_id, prerender_ids_to_abandon.front());
     prerender_ids_to_abandon.pop();
   }
 }
 
 bool PrerenderLinkManager::IsEmpty() const {
-  return ids_to_url_map_.empty();
+  return ids_to_handle_map_.empty();
 }
 
 }  // namespace prerender