Make PrerenderHandle an observer of PrerenderContents.

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 "base/memory/scoped_ptr.h"
 #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 "chrome/common/prerender_messages.h"
+#include "content/public/browser/render_process_host.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 "ui/gfx/size.h"
 
 using content::RenderViewHost;
 using content::SessionStorageNamespace;
 
+namespace {
+
+void Send(int child_id, IPC::Message* raw_message) {
+  scoped_ptr<IPC::Message> own_message(raw_message);
+  using content::RenderProcessHost;
+
+  RenderProcessHost* render_process_host = RenderProcessHost::FromID(child_id);
+  if (!render_process_host)
+    return;
+  render_process_host->Send(own_message.release());
+}
+
+}  // namespace
+
 namespace prerender {
 
 PrerenderLinkManager::PrerenderLinkManager(PrerenderManager* manager)
     : manager_(manager) {
 }
 
 PrerenderLinkManager::~PrerenderLinkManager() {
   for (IdPairToPrerenderHandleMap::iterator it = ids_to_handle_map_.begin();
        it != ids_to_handle_map_.end();
        ++it) {
     PrerenderHandle* prerender_handle = it->second;
-    prerender_handle->OnCancel();
+    DCHECK(!prerender_handle->IsPrerendering())
+        << "All running prerenders should stop at the same time as the "
+        << "PrerenderManager.";
     delete prerender_handle;
   }
 }
 
 bool PrerenderLinkManager::OnAddPrerender(int child_id,
                                           int prerender_id,
                                           const GURL& url,
                                           const content::Referrer& referrer,
                                           const gfx::Size& size,
                                           int render_view_route_id) {
   DVLOG(2) << "OnAddPrerender, child_id = " << child_id
            << ", prerender_id = " << prerender_id
            << ", url = " << url.spec();
   DVLOG(3) << "... referrer url = " << referrer.url.spec()
            << ", size = (" << size.width() << ", " << size.height() << ")"
            << ", render_view_route_id = " << render_view_route_id;
 
+
+  PrerenderHandle* prerender_handle =
+      manager_-> AddPrerenderFromLinkRelPrerender(

[mmenke, 2012/12/12 16:54:12]

nit:  Remove space

[gavinp, 2012/12/13 13:38:03]

Done.

+          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_handle_map_.count(child_and_prerender_id));
+  DCHECK_EQ(0u, ids_to_handle_map_.count(child_and_prerender_id));
+  ids_to_handle_map_[child_and_prerender_id] = prerender_handle;
 
-  scoped_ptr<PrerenderHandle> prerender_handle(
-      manager_->AddPrerenderFromLinkRelPrerender(
-          child_id, render_view_route_id, url, referrer, size));
-  if (prerender_handle.get()) {
-    std::pair<IdPairToPrerenderHandleMap::iterator, bool> insert_result =
-        ids_to_handle_map_.insert(std::make_pair(
-            child_and_prerender_id, static_cast<PrerenderHandle*>(NULL)));
-    DCHECK(insert_result.second);
-    delete insert_result.first->second;
-    insert_result.first->second = prerender_handle.release();
-    return true;
-  }
-  return false;
+  // If we are given a prerender that is already prerendering, we have missed
+  // the start event.
+  if (prerender_handle->IsPrerendering())
+    OnPrerenderStart(prerender_handle);
+  prerender_handle->AddObserver(this);
+  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);
   IdPairToPrerenderHandleMap::iterator id_to_handle_iter =
       ids_to_handle_map_.find(child_and_prerender_id);
   if (id_to_handle_iter == ids_to_handle_map_.end()) {
     DVLOG(5) << "... canceling a prerender that doesn't exist.";
     return;
   }
   PrerenderHandle* prerender_handle = id_to_handle_iter->second;
   prerender_handle->OnCancel();
-  RemovePrerender(id_to_handle_iter);
+
+  // OnCancel may end up calling back into OnPrerenderStop, and so
+  // |id_to_handle_iter| must be treated as invalidated.
+  id_to_handle_iter = ids_to_handle_map_.find(child_and_prerender_id);
+  if (id_to_handle_iter != ids_to_handle_map_.end())
+    RemovePrerender(id_to_handle_iter);
 }
 
 void PrerenderLinkManager::OnAbandonPrerender(int child_id, int prerender_id) {
   DVLOG(2) << "OnAbandonPrerender, child_id = " << child_id
            << ", prerender_id = " << prerender_id;
   const ChildAndPrerenderIdPair child_and_prerender_id(child_id, prerender_id);
   IdPairToPrerenderHandleMap::iterator id_to_handle_iter =
       ids_to_handle_map_.find(child_and_prerender_id);
   if (id_to_handle_iter == ids_to_handle_map_.end())
     return;
   PrerenderHandle* prerender_handle = id_to_handle_iter->second;
   prerender_handle->OnNavigateAway();
-  RemovePrerender(id_to_handle_iter);
+
+  // OnCancel may end up calling back into OnPrerenderStop, and so

[mmenke, 2012/12/11 19:53:45]

nit:  OnNavigateAway.

[mmenke, 2012/12/11 19:53:45]

Actually...Is there any way that OnNavigateAway would end up calling into
OnPrerenderStop?

[gavinp, 2012/12/13 13:38:03]

No. But we also need to leave the prerender in the map, since if the prerender
continues discovering new aliases, we want those to make it down to the
prerender dispatcher. So I've just tossed this whole code block out.

+  // |id_to_handle_iter| must be treated as invalidated.
+  id_to_handle_iter = ids_to_handle_map_.find(child_and_prerender_id);
+  if (id_to_handle_iter != ids_to_handle_map_.end())
+    RemovePrerender(id_to_handle_iter);
 }
 
 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 (IdPairToPrerenderHandleMap::iterator
@@ skipping 14 matching lines @@
   return ids_to_handle_map_.empty();
 }
 
 void PrerenderLinkManager::RemovePrerender(
     const IdPairToPrerenderHandleMap::iterator& id_to_handle_iter) {
   PrerenderHandle* prerender_handle = id_to_handle_iter->second;
   delete prerender_handle;
   ids_to_handle_map_.erase(id_to_handle_iter);
 }
 
+PrerenderLinkManager::IdPairToPrerenderHandleMap::iterator
+PrerenderLinkManager::FindPrerenderHandle(
+    PrerenderHandle* prerender_handle) {
+  for (IdPairToPrerenderHandleMap::iterator it = ids_to_handle_map_.begin();
+       it != ids_to_handle_map_.end(); ++it) {
+    if (it->second == prerender_handle)
+      return it;
+  }
+  return ids_to_handle_map_.end();
+}
+
+// In practice, this is always called from either
+// PrerenderLinkManager::OnAddPrerender in the regular case, or in the pending
+// prerender case, from PrerenderHandle::AdoptPrerenderDataFrom.
+void PrerenderLinkManager::OnPrerenderStart(
+    PrerenderHandle* prerender_handle) {
+  IdPairToPrerenderHandleMap::iterator it =
+      FindPrerenderHandle(prerender_handle);
+  if (it == ids_to_handle_map_.end())

[mmenke, 2012/12/11 19:53:45]

Does this ever happen?  Same goes for the next two functions.

We add a handle to the map at the same point we start listening to it.

RemovePrerender both removes the handle from the map and deletes it.

[gavinp, 2012/12/13 13:38:03]

Good point. Now a DCHECK.

+    return;
+  const int child_id = it->first.first;
+  const int prerender_id = it->first.second;
+
+  Send(child_id, new PrerenderMsg_OnPrerenderStart(prerender_id));
+}
+
+void PrerenderLinkManager::OnPrerenderAddAlias(
+    PrerenderHandle* prerender_handle,
+    const GURL& alias_url) {
+  IdPairToPrerenderHandleMap::iterator it =
+      FindPrerenderHandle(prerender_handle);
+  if (it == ids_to_handle_map_.end())
+    return;
+  const int child_id = it->first.first;
+  const int prerender_id = it->first.second;
+
+  Send(child_id, new PrerenderMsg_OnPrerenderAddAlias(prerender_id, alias_url));
+}
+
+void PrerenderLinkManager::OnPrerenderStop(
+    PrerenderHandle* prerender_handle) {
+  IdPairToPrerenderHandleMap::iterator it =
+      FindPrerenderHandle(prerender_handle);
+  if (it == ids_to_handle_map_.end())
+    return;
+  const int child_id = it->first.first;
+  const int prerender_id = it->first.second;
+
+  Send(child_id, new PrerenderMsg_OnPrerenderStop(prerender_id));
+  RemovePrerender(it);
+}
+
 }  // namespace prerender