Add a unified resource tracker shared between the proxy and the impl.

ppapi/shared_impl/resource_tracker.cc

+// Copyright (c) 2011 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/shared_impl/resource_tracker.h"
+
+#include "ppapi/shared_impl/id_assignment.h"
+#include "ppapi/shared_impl/resource.h"
+
+namespace ppapi {
+
+ResourceTracker::ResourceTracker() : last_resource_value_(0) {
+}
+
+ResourceTracker::~ResourceTracker() {
+}
+
+Resource* ResourceTracker::GetResource(PP_Resource res) const {
+  ResourceMap::const_iterator i = live_resources_.find(res);
+  if (i == live_resources_.end())
+    return NULL;
+  return i->second.first;
+}
+
+bool ResourceTracker::AddRefResource(PP_Resource res) {
+  DLOG_IF(ERROR, !CheckIdType(res, PP_ID_TYPE_RESOURCE))
+      << res << " is not a PP_Resource.";
+  ResourceMap::iterator i = live_resources_.find(res);
+  if (i == live_resources_.end())
+    return false;
+
+  // Prevent overflow of refcount.
+  if (i->second.second ==
+      std::numeric_limits<ResourceAndRefCount::second_type>::max())
+    return false;
+
+  // When we go from 0 to 1 plugin ref count, keep an additional "real" ref
+  // on its behalf.
+  if (i->second.second == 0)
+    i->second.first->AddRef();
+
+  i->second.second++;
+  return true;
+}
+
+bool ResourceTracker::ReleaseResource(PP_Resource res) {
+  DLOG_IF(ERROR, !CheckIdType(res, PP_ID_TYPE_RESOURCE))
+      << res << " is not a PP_Resource.";
+  ResourceMap::iterator i = live_resources_.find(res);
+  if (i == live_resources_.end())
+    return false;
+
+  // Prevent underflow of refcount.
+  if (i->second.second == 0)
+    return false;
+
+  i->second.second--;
+  if (i->second.second == 0) {
+    i->second.first->LastPluginRefWasDeleted();
+
+    // When we go from 0 to 1 plugin ref count, free the additional "real" ref

[dmichael (off chromium), 2011/08/17 19:02:54]

1 to 0

+    // on its behalf. THIS WILL MOST LIKELY RELEASE THE OBJECT AND REMOVE IT
+    // FROM OUR LIST.
+    i->second.first->Release();
+  }
+  return true;

[dmichael (off chromium), 2011/08/17 19:02:54]

The return value seems to be true if the resource existed and the ref-count was
successfully decremented. It could easily be interpreted to mean 'the last
refcount was removed and the resource was deleted'. If the return is never used,
maybe just make it return void? If this behavior is required, then please
document it in the header.

+}
+
+void ResourceTracker::DidCreateInstance(PP_Instance instance) {
+  // Due to the infrastructure of some tests, the instance is registered
+  // twice in a few cases. It would be nice not to do that and assert here
+  // instead.
+  if (instance_map_.find(instance) != instance_map_.end())
+    return;
+  instance_map_[instance] = linked_ptr<InstanceData>(new InstanceData);
+}
+
+void ResourceTracker::DidDeleteInstance(PP_Instance instance) {
+  InstanceMap::iterator found_instance = instance_map_.find(instance);
+
+  // Due to the infrastructure of some tests, the instance is uyregistered

[dmichael (off chromium), 2011/08/17 19:02:54]

uyregistered->unregistered

+  // twice in a few cases. It would be nice not to do that and assert here
+  // instead.
+  if (found_instance == instance_map_.end())
+    return;
+
+  InstanceData& data = *found_instance->second;
+
+  // Force release all plugin references to resources associated with the
+  // deleted instance. Make a copy since as we iterate through them, each one
+  // will remove itself from the tracking info individually.
+  ResourceSet to_delete = data.resources;
+  ResourceSet::iterator cur = to_delete.begin();
+  while (cur != to_delete.end()) {
+    // Note that it's remotely possible for the object to already be deleted
+    // from the live resources. One case is if a resource object is holding
+    // the last ref to another. When we release the first one, it will release
+    // the second one. So the second one will be gone when we eventually get
+    // to it.
+    ResourceMap::iterator found_resource = live_resources_.find(*cur);
+    if (found_resource != live_resources_.end()) {
+      Resource* resource = found_resource->second.first;
+      if (found_resource->second.second > 0) {
+        resource->LastPluginRefWasDeleted();
+        found_resource->second.second = 0;
+
+        // This will most likely delete the resource object and remove it
+        // from the live_resources_ list.
+        resource->Release();
+      }
+    }
+
+    cur++;
+  }
+
+  // In general the above pass will delete all the resources and there won't
+  // be any left in the map. However, if parts of the implementation are still
+  // holding on to internal refs, we need to tell them that the instance is
+  // gone.
+  to_delete = data.resources;
+  cur = to_delete.begin();
+  while (cur != to_delete.end()) {
+    ResourceMap::iterator found_resource = live_resources_.find(*cur);
+    if (found_resource != live_resources_.end())
+      found_resource->second.first->InstanceWasDeleted();
+    cur++;
+  }
+
+  instance_map_.erase(instance);
+}
+
+int ResourceTracker::GetLiveObjectsForInstance(PP_Instance instance) const {
+  InstanceMap::const_iterator found = instance_map_.find(instance);
+  if (found == instance_map_.end())
+    return 0;
+  return static_cast<int>(found->second->resources.size());
+}
+
+PP_Resource ResourceTracker::AddResource(Resource* object) {
+  // If the plugin manages to create too many resources, don't do crazy stuff.

[dmichael (off chromium), 2011/08/17 19:02:54]

Now that we're generating a resource for each input event (including, e.g.,
mouse move), and since we only have 29 bits to work with, it's getting almost
plausible that a long-running plugin would exhaust resources. Back of the
envelope says that at 1000/sec (I know, probably unlikely) it would take just
over 6 days.

Not for this CL...  but I think we might want to consider a more careful ID
assignment soon.

+  if (last_resource_value_ == kMaxPPId)
+    return 0;
+
+  // If you hit this somebody forgot to call DidCreateInstance or the resource
+  // was created with an invalid PP_Instance.
+  DCHECK(instance_map_.find(object->pp_instance()) != instance_map_.end());
+
+  PP_Resource new_id = MakeTypedId(++last_resource_value_, PP_ID_TYPE_RESOURCE);
+  instance_map_[object->pp_instance()]->resources.insert(new_id);
+
+  live_resources_[new_id] = ResourceAndRefCount(object, 0);
+  return new_id;
+}
+
+void ResourceTracker::RemoveResource(Resource* object) {
+  PP_Resource pp_resource = object->pp_resource();
+  if (object->pp_instance())
+    instance_map_[object->pp_instance()]->resources.erase(pp_resource);
+  live_resources_.erase(pp_resource);
+}
+
+
+}  // namespace ppapi