Add ability to create pending resource hosts.

Allows the host side to register a ResourceHost as pending and send an ID to the plugin, to be connected to a PluginResource at a future time.

BUG=


Review URL: https://chromiumcodereview.appspot.com/11414147

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@171099 0039d316-1c4b-4281-b951-d872f2087c98

ppapi/host/ppapi_host.cc

@@ -28,7 +28,8 @@ const size_t kMaxResourcesPerPlugin = 1 << 14;
 PpapiHost::PpapiHost(IPC::Sender* sender,
                      const PpapiPermissions& perms)
     : sender_(sender),
-      permissions_(perms) {
+      permissions_(perms),
+      next_pending_resource_host_id_(1) {
 }
 
 PpapiHost::~PpapiHost() {
@@ -51,6 +52,8 @@ bool PpapiHost::OnMessageReceived(const IPC::Message& msg) {
                                     OnHostMsgResourceSyncCall)
     IPC_MESSAGE_HANDLER(PpapiHostMsg_ResourceCreated,
                         OnHostMsgResourceCreated)
+    IPC_MESSAGE_HANDLER(PpapiHostMsg_AttachToPendingHost,
+                        OnHostMsgAttachToPendingHost)
     IPC_MESSAGE_HANDLER(PpapiHostMsg_ResourceDestroyed,
                         OnHostMsgResourceDestroyed)
     IPC_MESSAGE_UNHANDLED(handled = false)
@@ -81,10 +84,21 @@ void PpapiHost::SendReply(const ReplyMessageContext& context,
 
 void PpapiHost::SendUnsolicitedReply(PP_Resource resource,
                                      const IPC::Message& msg) {
+  DCHECK(resource);  // If this fails, host is probably pending.
   proxy::ResourceMessageReplyParams params(resource, 0);
   Send(new PpapiPluginMsg_ResourceReply(params, msg));
 }
 
+int PpapiHost::AddPendingResourceHost(scoped_ptr<ResourceHost> resource_host) {
+  // The resource ID should not be assigned.
+  DCHECK(resource_host->pp_resource() == 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());
 }
@@ -151,10 +165,27 @@ void PpapiHost::OnHostMsgResourceCreated(
     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);
+  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()) {

ppapi/host/ppapi_host.h

@@ -61,6 +61,11 @@ class PPAPI_HOST_EXPORT PpapiHost : public IPC::Sender, public IPC::Listener {
   // Sends the given unsolicited reply message to the plugin.
   void SendUnsolicitedReply(PP_Resource resource, const IPC::Message& msg);
 
+  // Adds the given host resource as a pending one (with no corresponding
+  // PluginResource object and no PP_Resource ID yet). The pending resource ID
+  // is returned. See PpapiHostMsg_AttachToPendingHost.
+  int AddPendingResourceHost(scoped_ptr<ResourceHost> resource_host);
+
   // Adds the given host factory filter to the host. The PpapiHost will take
   // ownership of the pointer.
   void AddHostFactoryFilter(scoped_ptr<HostFactory> filter);
@@ -90,6 +95,7 @@ class PPAPI_HOST_EXPORT PpapiHost : public IPC::Sender, public IPC::Listener {
   void OnHostMsgResourceCreated(const proxy::ResourceMessageCallParams& param,
                                 PP_Instance instance,
                                 const IPC::Message& nested_msg);
+  void OnHostMsgAttachToPendingHost(PP_Resource resource, int pending_host_id);
   void OnHostMsgResourceDestroyed(PP_Resource resource);
 
   // Non-owning pointer.
@@ -112,6 +118,13 @@ class PPAPI_HOST_EXPORT PpapiHost : public IPC::Sender, public IPC::Listener {
   typedef std::map<PP_Resource, linked_ptr<ResourceHost> > ResourceMap;
   ResourceMap resources_;
 
+  // Resources that have been created in the host and have not yet had the
+  // corresponding PluginResource associated with them.
+  // See PpapiHostMsg_AttachToPendingHost.
+  typedef std::map<int, linked_ptr<ResourceHost> > PendingHostResourceMap;
+  PendingHostResourceMap pending_resource_hosts_;
+  int next_pending_resource_host_id_;
+
   DISALLOW_COPY_AND_ASSIGN(PpapiHost);
 };
 

ppapi/host/resource_host.cc

@@ -4,6 +4,7 @@
 
 #include "ppapi/host/resource_host.h"
 
+#include "base/logging.h"
 #include "ppapi/c/pp_errors.h"
 #include "ppapi/host/ppapi_host.h"
 #include "ppapi/host/resource_message_filter.h"
@@ -36,6 +37,12 @@ bool ResourceHost::HandleMessage(const IPC::Message& msg,
   return true;
 }
 
+void ResourceHost::SetPPResourceForPendingHost(PP_Resource pp_resource) {
+  DCHECK(!pp_resource_);
+  pp_resource_ = pp_resource;
+  DidConnectPendingHostToResource();
+}
+
 void ResourceHost::SendReply(const ReplyMessageContext& context,
                              const IPC::Message& msg) {
   host_->SendReply(context, msg);

ppapi/host/resource_host.h

@@ -43,6 +43,14 @@ class PPAPI_HOST_EXPORT ResourceHost : public ResourceMessageHandler {
   virtual bool HandleMessage(const IPC::Message& msg,
                              HostMessageContext* context) OVERRIDE;
 
+  // Sets the PP_Resource ID when the plugin attaches to a pending resource
+  // host. This will notify subclasses by calling
+  // DidConnectPendingHostToResource.
+  //
+  // The current PP_Resource for all pending hosts should be 0.  See
+  // PpapiHostMsg_AttachToPendingHost.
+  void SetPPResourceForPendingHost(PP_Resource pp_resource);
+
   virtual void SendReply(const ReplyMessageContext& context,
                          const IPC::Message& msg) OVERRIDE;
 
@@ -55,6 +63,13 @@ class PPAPI_HOST_EXPORT ResourceHost : public ResourceMessageHandler {
   // ResourceHosts to easily handle messages on other threads.
   void AddFilter(scoped_refptr<ResourceMessageFilter> filter);
 
+  // Called when this resource host is pending and the corresponding plugin has
+  // just connected to it. The host resource subclass can implement this
+  // function if it wants to do processing (typically sending queued data).
+  //
+  // The PP_Resource will be valid for this call but not before.
+  virtual void DidConnectPendingHostToResource() {}
+
  private:
   // The host that owns this object.
   PpapiHost* host_;

ppapi/proxy/plugin_resource.cc

@@ -81,6 +81,20 @@ void PluginResource::SendCreate(Destination dest, const IPC::Message& msg) {
       new PpapiHostMsg_ResourceCreated(params, pp_instance(), msg));
 }
 
+void PluginResource::AttachToPendingHost(Destination dest,
+                                         int pending_host_id) {
+  // Connecting to a pending host is a replacement for "create".
+  if (dest == RENDERER) {
+    DCHECK(!sent_create_to_renderer_);
+    sent_create_to_renderer_ = true;
+  } else {
+    DCHECK(!sent_create_to_browser_);
+    sent_create_to_browser_ = true;
+  }
+  GetSender(dest)->Send(
+      new PpapiHostMsg_AttachToPendingHost(pp_resource(), pending_host_id));
+}
+
 void PluginResource::Post(Destination dest, const IPC::Message& msg) {
   ResourceMessageCallParams params(pp_resource(), GetNextSequence());
   SendResourceCall(dest, params, msg);

ppapi/proxy/plugin_resource.h

@@ -62,6 +62,13 @@ class PPAPI_PROXY_EXPORT PluginResource : public Resource {
   // Sends a create message to the browser or renderer for the current resource.
   void SendCreate(Destination dest, const IPC::Message& msg);
 
+  // When the host returnes a resource to the plugin, it will create a pending
+  // ResourceHost and send an ID back to the plugin that identifies the pending
+  // object. The plugin uses this function to connect the plugin resource with
+  // the pending host resource. See also PpapiHostMsg_AttachToPendingHost. This
+  // is in lieu of sending a create message.
+  void AttachToPendingHost(Destination dest, int pending_host_id);
+
   // Sends the given IPC message as a resource request to the host
   // corresponding to this resource object and does not expect a reply.
   void Post(Destination dest, const IPC::Message& msg);

ppapi/proxy/ppapi_messages.h

@@ -1405,6 +1405,20 @@ IPC_MESSAGE_CONTROL3(PpapiHostMsg_ResourceCreated,
 IPC_MESSAGE_CONTROL1(PpapiHostMsg_ResourceDestroyed,
                      PP_Resource /* resource */)
 
+// Most resources are created by the plugin, which then sends a ResourceCreated
+// message to create a corresponding ResourceHost in the renderer or browser
+// host process. However, some resources are first created in the host and
+// "pushed" or returned to the plugin.
+//
+// In this case, the host will create a "pending" ResourceHost object which
+// is identified by an ID. The ID is sent to the plugin process and the
+// PluginResource object is created. This message is sent from the plugin to
+// the host process to connect the PluginResource and the pending ResourceHost
+// (at which point, it's no longer pending).
+IPC_MESSAGE_CONTROL2(PpapiHostMsg_AttachToPendingHost,
+                     PP_Resource /* resource */,
+                     int /* pending_host_id */)
+
 // A resource call is a request from the plugin to the host. It may or may not
 // require a reply, depending on the params. The nested message will be
 // resource-type-specific.