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// 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/proxy/plugin_var_tracker.h"
#include "base/memory/ref_counted.h"
#include "base/memory/singleton.h"
#include "ppapi/c/ppb_var.h"
#include "ppapi/proxy/plugin_dispatcher.h"
#include "ppapi/proxy/ppapi_messages.h"
#include "ppapi/proxy/interface_id.h"
namespace pp {
namespace proxy {
namespace {
// When non-NULL, this object overrides the VarTrackerSingleton.
PluginVarTracker* var_tracker_override = NULL;
} // namespace
PluginVarTracker::HostVar::HostVar(PluginDispatcher* d, VarID i)
: dispatcher(d),
host_object_id(i) {
}
bool PluginVarTracker::HostVar::operator<(const HostVar& other) const {
if (dispatcher < other.dispatcher)
return true;
if (other.dispatcher < dispatcher)
return false;
return host_object_id < other.host_object_id;
}
PluginVarTracker::PluginVarInfo::PluginVarInfo(const HostVar& host_var)
: host_var(host_var),
ref_count(0),
track_with_no_reference_count(0) {
}
PluginVarTracker::PluginVarTracker() : last_plugin_var_id_(0) {
}
PluginVarTracker::~PluginVarTracker() {
}
// static
void PluginVarTracker::SetInstanceForTest(PluginVarTracker* tracker) {
var_tracker_override = tracker;
}
// static
PluginVarTracker* PluginVarTracker::GetInstance() {
if (var_tracker_override)
return var_tracker_override;
return Singleton<PluginVarTracker>::get();
}
PluginVarTracker::VarID PluginVarTracker::MakeString(const std::string& str) {
return MakeString(str.c_str(), str.length());
}
PluginVarTracker::VarID PluginVarTracker::MakeString(const char* str,
uint32_t len) {
std::pair<VarIDStringMap::iterator, bool>
iter_success_pair(var_id_to_string_.end(), false);
VarID new_id(0);
RefCountedStringPtr str_ptr(new RefCountedString(str, len));
// Pick new IDs until one is successfully inserted. This loop is very unlikely
// to ever run a 2nd time, since we have ~2^63 possible IDs to exhaust.
while (!iter_success_pair.second) {
new_id = GetNewVarID();
iter_success_pair =
var_id_to_string_.insert(VarIDStringMap::value_type(new_id, str_ptr));
}
iter_success_pair.first->second->AddRef();
return new_id;
}
const std::string* PluginVarTracker::GetExistingString(
const PP_Var& var) const {
if (var.type != PP_VARTYPE_STRING)
return NULL;
VarIDStringMap::const_iterator found =
var_id_to_string_.find(var.value.as_id);
if (found != var_id_to_string_.end())
return &found->second->value();
return NULL;
}
void PluginVarTracker::AddRef(const PP_Var& var) {
if (var.type == PP_VARTYPE_STRING) {
VarIDStringMap::iterator found = var_id_to_string_.find(var.value.as_id);
if (found == var_id_to_string_.end()) {
NOTREACHED() << "Requesting to addref an unknown string.";
return;
}
found->second->AddRef();
} else if (var.type == PP_VARTYPE_OBJECT && var.value.as_id != 0) {
PluginVarInfoMap::iterator found = plugin_var_info_.find(var.value.as_id);
if (found == plugin_var_info_.end()) {
NOTREACHED() << "Requesting to addref an unknown object.";
return;
}
PluginVarInfo& info = found->second;
if (info.ref_count == 0) {
// Got an AddRef for an object we have no existing reference for.
// We need to tell the browser we've taken a ref. This comes up when the
// browser passes an object as an input param and holds a ref for us.
// This must be a sync message since otherwise the "addref" will actually
// occur after the return to the browser of the sync function that
// presumably sent the object.
SendAddRefObjectMsg(info.host_var);
}
info.ref_count++;
}
}
void PluginVarTracker::Release(const PP_Var& var) {
if (var.type == PP_VARTYPE_STRING) {
VarIDStringMap::iterator found = var_id_to_string_.find(var.value.as_id);
if (found == var_id_to_string_.end()) {
NOTREACHED() << "Requesting to release an unknown string.";
return;
}
found->second->Release();
// If there is only 1 reference left, it's the map's reference. Erase it
// from the map, which will delete the string.
if (found->second->HasOneRef())
var_id_to_string_.erase(found);
} else if (var.type == PP_VARTYPE_OBJECT) {
PluginVarInfoMap::iterator found = plugin_var_info_.find(var.value.as_id);
if (found == plugin_var_info_.end()) {
NOTREACHED() << "Requesting to release an unknown object.";
return;
}
PluginVarInfo& info = found->second;
if (info.ref_count == 0) {
NOTREACHED() << "Releasing an object with zero ref.";
return;
}
info.ref_count--;
if (info.ref_count == 0)
SendReleaseObjectMsg(info.host_var);
DeletePluginVarInfoIfNecessary(found);
}
}
PP_Var PluginVarTracker::ReceiveObjectPassRef(const PP_Var& var,
PluginDispatcher* dispatcher) {
DCHECK(var.type == PP_VARTYPE_OBJECT);
// Find the plugin info.
PluginVarInfoMap::iterator found =
FindOrMakePluginVarFromHostVar(var, dispatcher);
if (found == plugin_var_info_.end()) {
// The above code should have always made an entry in the map.
NOTREACHED();
return PP_MakeUndefined();
}
// Fix up the references. The host (renderer) just sent us a ref. The
// renderer has addrefed the var in its tracker for us since it's returning
// it.
PluginVarInfo& info = found->second;
if (info.ref_count == 0) {
// We don't have a reference to this already, then we just add it to our
// tracker and use that one ref.
info.ref_count = 1;
} else {
// We already have a reference to it, that means the renderer now has two
// references on our behalf. We want to transfer that extra reference to
// our list. This means we addref in the plugin, and release the extra one
// in the renderer.
SendReleaseObjectMsg(info.host_var);
info.ref_count++;
}
PP_Var ret;
ret.type = PP_VARTYPE_OBJECT;
ret.value.as_id = found->first;
return ret;
}
PP_Var PluginVarTracker::TrackObjectWithNoReference(
const PP_Var& host_var,
PluginDispatcher* dispatcher) {
DCHECK(host_var.type == PP_VARTYPE_OBJECT);
PluginVarInfoMap::iterator found =
FindOrMakePluginVarFromHostVar(host_var, dispatcher);
if (found == plugin_var_info_.end()) {
// The above code should have always made an entry in the map.
NOTREACHED();
return PP_MakeUndefined();
}
found->second.track_with_no_reference_count++;
PP_Var ret;
ret.type = PP_VARTYPE_OBJECT;
ret.value.as_id = found->first;
return ret;
}
void PluginVarTracker::StopTrackingObjectWithNoReference(
const PP_Var& plugin_var) {
DCHECK(plugin_var.type == PP_VARTYPE_OBJECT);
PluginVarInfoMap::iterator found = plugin_var_info_.find(
plugin_var.value.as_id);
if (found == plugin_var_info_.end()) {
NOTREACHED();
return;
}
found->second.track_with_no_reference_count--;
DeletePluginVarInfoIfNecessary(found);
}
PP_Var PluginVarTracker::GetHostObject(const PP_Var& plugin_object) const {
DCHECK(plugin_object.type == PP_VARTYPE_OBJECT);
PluginVarInfoMap::const_iterator found = plugin_var_info_.find(
plugin_object.value.as_id);
if (found == plugin_var_info_.end()) {
NOTREACHED();
return PP_MakeUndefined();
}
PP_Var ret;
ret.type = PP_VARTYPE_OBJECT;
ret.value.as_id = found->second.host_var.host_object_id;
return ret;
}
PluginDispatcher* PluginVarTracker::DispatcherForPluginObject(
const PP_Var& plugin_object) const {
DCHECK(plugin_object.type == PP_VARTYPE_OBJECT);
PluginVarInfoMap::const_iterator found = plugin_var_info_.find(
plugin_object.value.as_id);
if (found != plugin_var_info_.end())
return found->second.host_var.dispatcher;
return NULL;
}
void PluginVarTracker::ReleaseHostObject(PluginDispatcher* dispatcher,
const PP_Var& host_object) {
// Convert the host object to a normal var valid in the plugin.
DCHECK(host_object.type == PP_VARTYPE_OBJECT);
HostVarToPluginVarMap::iterator found = host_var_to_plugin_var_.find(
HostVar(dispatcher, host_object.value.as_id));
if (found == host_var_to_plugin_var_.end()) {
NOTREACHED();
return;
}
// Now just release the object like normal.
PP_Var plugin_object;
plugin_object.type = PP_VARTYPE_OBJECT;
plugin_object.value.as_id = found->second;
Release(plugin_object);
}
int PluginVarTracker::GetRefCountForObject(const PP_Var& plugin_object) {
PluginVarInfoMap::iterator found = plugin_var_info_.find(
plugin_object.value.as_id);
if (found == plugin_var_info_.end())
return -1;
return found->second.ref_count;
}
int PluginVarTracker::GetTrackedWithNoReferenceCountForObject(
const PP_Var& plugin_object) {
PluginVarInfoMap::iterator found = plugin_var_info_.find(
plugin_object.value.as_id);
if (found == plugin_var_info_.end())
return -1;
return found->second.track_with_no_reference_count;
}
void PluginVarTracker::SendAddRefObjectMsg(const HostVar& host_var) {
int unused;
host_var.dispatcher->Send(new PpapiHostMsg_PPBVar_AddRefObject(
INTERFACE_ID_PPB_VAR_DEPRECATED, host_var.host_object_id, &unused));
}
void PluginVarTracker::SendReleaseObjectMsg(const HostVar& host_var) {
host_var.dispatcher->Send(new PpapiHostMsg_PPBVar_ReleaseObject(
INTERFACE_ID_PPB_VAR_DEPRECATED, host_var.host_object_id));
}
PluginVarTracker::PluginVarInfoMap::iterator
PluginVarTracker::FindOrMakePluginVarFromHostVar(const PP_Var& var,
PluginDispatcher* dispatcher) {
DCHECK(var.type == PP_VARTYPE_OBJECT);
HostVar host_var(dispatcher, var.value.as_id);
HostVarToPluginVarMap::iterator found =
host_var_to_plugin_var_.find(host_var);
if (found != host_var_to_plugin_var_.end()) {
PluginVarInfoMap::iterator ret = plugin_var_info_.find(found->second);
DCHECK(ret != plugin_var_info_.end());
return ret; // Already know about this var return the ID.
}
// Make a new var, adding references to both maps.
VarID new_plugin_var_id = GetNewVarID();
host_var_to_plugin_var_[host_var] = new_plugin_var_id;
return plugin_var_info_.insert(
std::make_pair(new_plugin_var_id, PluginVarInfo(host_var))).first;
}
void PluginVarTracker::DeletePluginVarInfoIfNecessary(
PluginVarInfoMap::iterator iter) {
if (iter->second.ref_count != 0 ||
iter->second.track_with_no_reference_count != 0)
return; // Object still alive.
// Object ref counts are all zero, delete from both maps.
DCHECK(host_var_to_plugin_var_.find(iter->second.host_var) !=
host_var_to_plugin_var_.end());
host_var_to_plugin_var_.erase(iter->second.host_var);
plugin_var_info_.erase(iter);
}
PluginVarTracker::VarID PluginVarTracker::GetNewVarID() {
if (last_plugin_var_id_ == std::numeric_limits<VarID>::max())
last_plugin_var_id_ = 0;
return ++last_plugin_var_id_;
}
} // namesace proxy
} // namespace pp
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