Allow renderer to create pepper ResourceHosts in the browser

ppapi/host/ppapi_host.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 "ppapi/host/ppapi_host.h"
 
 #include "base/logging.h"
 #include "ppapi/c/pp_errors.h"
 #include "ppapi/host/host_factory.h"
 #include "ppapi/host/host_message_context.h"
@@ skipping 81 matching lines @@
 void PpapiHost::SendUnsolicitedReply(PP_Resource resource,
                                      const IPC::Message& msg) {
   TRACE_EVENT2("ppapi proxy", "PpapiHost::SendUnsolicitedReply",
                "Class", IPC_MESSAGE_ID_CLASS(msg.type()),
                "Line", IPC_MESSAGE_ID_LINE(msg.type()));
   DCHECK(resource);  // If this fails, host is probably pending.
   proxy::ResourceMessageReplyParams params(resource, 0);
   Send(new PpapiPluginMsg_ResourceReply(params, msg));
 }
 
+scoped_ptr<ResourceHost> PpapiHost::CreateResourceHost(
+    const proxy::ResourceMessageCallParams& params,
+    PP_Instance instance,
+    const IPC::Message& nested_msg) {
+  scoped_ptr<ResourceHost> resource_host;
+  DCHECK(!host_factory_filters_.empty());  // Caller forgot to add a factory.
+  for (size_t i = 0; i < host_factory_filters_.size(); i++) {
+    resource_host = host_factory_filters_[i]->CreateResourceHost(
+        this, params, instance, nested_msg).Pass();
+    if (resource_host.get())
+      break;
+  }
+  return resource_host.Pass();
+}
+
 int PpapiHost::AddPendingResourceHost(scoped_ptr<ResourceHost> resource_host) {
   // The resource ID should not be assigned.
-  DCHECK(resource_host->pp_resource() == 0);
+  if (!resource_host.get() || resource_host->pp_resource() != 0) {
+    NOTREACHED();
+    return 0;
+  }
+
+  if (pending_resource_hosts_.size() + resources_.size()
+      >= kMaxResourcesPerPlugin) {
+    return 0;
+  }
 
   int pending_id = next_pending_resource_host_id_++;
   pending_resource_hosts_[pending_id] =
       linked_ptr<ResourceHost>(resource_host.release());
   return pending_id;
 }
 
 void PpapiHost::AddHostFactoryFilter(scoped_ptr<HostFactory> filter) {
   host_factory_filters_.push_back(filter.release());
 }
@@ skipping 46 matching lines @@
   }
 }
 
 void PpapiHost::OnHostMsgResourceCreated(
     const proxy::ResourceMessageCallParams& params,
     PP_Instance instance,
     const IPC::Message& nested_msg) {
   TRACE_EVENT2("ppapi proxy", "PpapiHost::OnHostMsgResourceCreated",
                "Class", IPC_MESSAGE_ID_CLASS(nested_msg.type()),
                "Line", IPC_MESSAGE_ID_LINE(nested_msg.type()));
-  if (resources_.size() >= kMaxResourcesPerPlugin)
+
+  if (pending_resource_hosts_.size() + resources_.size()
+      >= kMaxResourcesPerPlugin) {
     return;
+  }
 
   // Run through all filters until one grabs this message.
-  scoped_ptr<ResourceHost> resource_host;
-  DCHECK(!host_factory_filters_.empty());  // Caller forgot to add a factory.
-  for (size_t i = 0; i < host_factory_filters_.size(); i++) {
-    resource_host = host_factory_filters_[i]->CreateResourceHost(
-        this, params, instance, nested_msg).Pass();
-    if (resource_host.get())
-      break;
-  }
+  scoped_ptr<ResourceHost> resource_host = CreateResourceHost(params, instance,
+                                                              nested_msg);
+
   if (!resource_host.get()) {
     NOTREACHED();
     return;
   }
 
   // Resource should have been assigned a nonzero PP_Resource.
   DCHECK(resource_host->pp_resource());
 
   resources_[params.pp_resource()] =
       linked_ptr<ResourceHost>(resource_host.release());
 }
 
 void PpapiHost::OnHostMsgAttachToPendingHost(PP_Resource pp_resource,
                                              int pending_host_id) {
   PendingHostResourceMap::iterator found =
       pending_resource_hosts_.find(pending_host_id);
   if (found == pending_resource_hosts_.end()) {
     // Plugin sent a bad ID.
     NOTREACHED();
     return;
   }
   found->second->SetPPResourceForPendingHost(pp_resource);
+  if (resources_.size() >= kMaxResourcesPerPlugin)
+    return;

[teravest, 2013/05/29 15:19:36]

What should callers of AttachToPendingHost() do to detect this case? Since the
information remains in pending_resource_hosts_, it looks like you're allowing
the caller to retry on failure, but I don't know how it would be detected.

[raymes, 2013/05/29 15:53:03]

Oops this shouldn't be here. I already added the checks in the 2 places where we
add things to the map.

   resources_[pp_resource] = found->second;
   pending_resource_hosts_.erase(found);
 }
 
 void PpapiHost::OnHostMsgResourceDestroyed(PP_Resource resource) {
   ResourceMap::iterator found = resources_.find(resource);
   if (found == resources_.end()) {
     NOTREACHED();
     return;
   }
   // Invoking the HostResource destructor might result in looking up the
   // PP_Resource in resources_. std::map is not well specified as to whether the
   // element will be there or not. Therefore, we delay destruction of the
   // HostResource until after we've made sure the map no longer contains
   // |resource|.
   linked_ptr<ResourceHost> delete_at_end_of_scope(found->second);
   resources_.erase(found);
 }
 
 ResourceHost* PpapiHost::GetResourceHost(PP_Resource resource) const {
   ResourceMap::const_iterator found = resources_.find(resource);
   return found == resources_.end() ? NULL : found->second.get();
 }
 
 }  // namespace host
 }  // namespace ppapi