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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/shared_impl/var_tracker.h"
#include <limits>
#include "base/logging.h"
#include "ppapi/shared_impl/id_assignment.h"
#include "ppapi/shared_impl/var.h"
namespace ppapi {
VarTracker::VarInfo::VarInfo()
: var(),
ref_count(0),
track_with_no_reference_count(0) {
}
VarTracker::VarInfo::VarInfo(Var* v, int input_ref_count)
: var(v),
ref_count(input_ref_count),
track_with_no_reference_count(0) {
}
VarTracker::VarTracker() : last_var_id_(0) {
}
VarTracker::~VarTracker() {
}
int32 VarTracker::AddVar(Var* var) {
return AddVarInternal(var, ADD_VAR_TAKE_ONE_REFERENCE);
}
Var* VarTracker::GetVar(int32 var_id) const {
VarMap::const_iterator result = live_vars_.find(var_id);
if (result == live_vars_.end())
return NULL;
return result->second.var.get();
}
Var* VarTracker::GetVar(const PP_Var& var) const {
if (!IsVarTypeRefcounted(var.type))
return NULL;
return GetVar(static_cast<int32>(var.value.as_id));
}
bool VarTracker::AddRefVar(int32 var_id) {
DLOG_IF(ERROR, !CheckIdType(var_id, PP_ID_TYPE_VAR))
<< var_id << " is not a PP_Var ID.";
VarMap::iterator found = live_vars_.find(var_id);
if (found == live_vars_.end()) {
NOTREACHED(); // Invalid var.
return false;
}
VarInfo& info = found->second;
if (info.ref_count == 0) {
// All live vars with no refcount should be tracked objects.
DCHECK(info.track_with_no_reference_count > 0);
DCHECK(info.var->GetType() == PP_VARTYPE_OBJECT);
TrackedObjectGettingOneRef(found);
}
// Basic refcount increment.
info.ref_count++;
return true;
}
bool VarTracker::AddRefVar(const PP_Var& var) {
if (!IsVarTypeRefcounted(var.type))
return false;
return AddRefVar(static_cast<int32>(var.value.as_id));
}
bool VarTracker::ReleaseVar(int32 var_id) {
DLOG_IF(ERROR, !CheckIdType(var_id, PP_ID_TYPE_VAR))
<< var_id << " is not a PP_Var ID.";
VarMap::iterator found = live_vars_.find(var_id);
if (found == live_vars_.end()) {
NOTREACHED() << "Unref-ing an invalid var";
return false;
}
VarInfo& info = found->second;
if (info.ref_count == 0) {
NOTREACHED() << "Releasing an object with zero ref";
return false;
}
info.ref_count--;
if (info.ref_count == 0) {
if (info.var->GetType() == PP_VARTYPE_OBJECT) {
// Objects have special requirements and may not necessarily be released
// when the refcount goes to 0.
ObjectGettingZeroRef(found);
} else {
// All other var types can just be released.
DCHECK(info.track_with_no_reference_count == 0);
live_vars_.erase(found);
}
}
return true;
}
bool VarTracker::ReleaseVar(const PP_Var& var) {
if (!IsVarTypeRefcounted(var.type))
return false;
return ReleaseVar(static_cast<int32>(var.value.as_id));
}
int32 VarTracker::AddVarInternal(Var* var, AddVarRefMode mode) {
// If the plugin manages to create millions of strings.
if (last_var_id_ == std::numeric_limits<int32>::max() >> kPPIdTypeBits)
return 0;
int32 new_id = MakeTypedId(++last_var_id_, PP_ID_TYPE_VAR);
live_vars_.insert(std::make_pair(new_id,
VarInfo(var, mode == ADD_VAR_TAKE_ONE_REFERENCE ? 1 : 0)));
return new_id;
}
VarTracker::VarMap::iterator VarTracker::GetLiveVar(int32 id) {
return live_vars_.find(id);
}
VarTracker::VarMap::iterator VarTracker::GetLiveVar(const PP_Var& var) {
return live_vars_.find(static_cast<int32>(var.value.as_id));
}
VarTracker::VarMap::const_iterator VarTracker::GetLiveVar(
const PP_Var& var) const {
return live_vars_.find(static_cast<int32>(var.value.as_id));
}
bool VarTracker::IsVarTypeRefcounted(PP_VarType type) const {
return type == PP_VARTYPE_STRING || type == PP_VARTYPE_OBJECT;
}
void VarTracker::TrackedObjectGettingOneRef(VarMap::const_iterator obj) {
// Anybody using tracked objects should override this.
NOTREACHED();
}
void VarTracker::ObjectGettingZeroRef(VarMap::iterator iter) {
DeleteObjectInfoIfNecessary(iter);
}
bool VarTracker::DeleteObjectInfoIfNecessary(VarMap::iterator iter) {
if (iter->second.ref_count != 0 ||
iter->second.track_with_no_reference_count != 0)
return false; // Object still alive.
live_vars_.erase(iter);
return true;
}
} // namespace ppapi
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