// Copyright 2012 The Chromium Authors
// 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 <algorithm>
#include <limits>
#include <memory>
#include "base/logging.h"
#include "base/memory/unsafe_shared_memory_region.h"
#include "ppapi/shared_impl/host_resource.h"
#include "ppapi/shared_impl/id_assignment.h"
#include "ppapi/shared_impl/proxy_lock.h"
#include "ppapi/shared_impl/resource_var.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(ThreadMode thread_mode) : last_var_id_(0) {
if (thread_mode == SINGLE_THREADED)
thread_checker_ = std::make_unique<base::ThreadChecker>();
}
VarTracker::~VarTracker() {}
void VarTracker::CheckThreadingPreconditions() const {
DCHECK(!thread_checker_ || thread_checker_->CalledOnValidThread());
#ifndef NDEBUG
ProxyLock::AssertAcquired();
#endif
}
int32_t VarTracker::AddVar(Var* var) {
CheckThreadingPreconditions();
return AddVarInternal(var, ADD_VAR_TAKE_ONE_REFERENCE);
}
Var* VarTracker::GetVar(int32_t var_id) const {
CheckThreadingPreconditions();
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 {
CheckThreadingPreconditions();
if (!IsVarTypeRefcounted(var.type))
return NULL;
return GetVar(static_cast<int32_t>(var.value.as_id));
}
bool VarTracker::AddRefVar(int32_t var_id) {
CheckThreadingPreconditions();
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.
}
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++;
CHECK(info.ref_count != std::numeric_limits<decltype(info.ref_count)>::max());
return true;
}
bool VarTracker::AddRefVar(const PP_Var& var) {
CheckThreadingPreconditions();
if (!IsVarTypeRefcounted(var.type))
return true;
return AddRefVar(static_cast<int32_t>(var.value.as_id));
}
bool VarTracker::ReleaseVar(int32_t var_id) {
CheckThreadingPreconditions();
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())
return false;
VarInfo& info = found->second;
if (info.ref_count == 0) {
NOTREACHED() << "Releasing an object with zero ref";
}
info.ref_count--;
if (info.ref_count == 0) {
// Hold a reference to the Var until it is erased so that we don't re-enter
// live_vars_.erase() during deletion.
// TODO(raymes): Make deletion of Vars iterative instead of recursive.
scoped_refptr<Var> var(info.var);
if (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);
var->ResetVarID();
live_vars_.erase(found);
}
}
return true;
}
bool VarTracker::ReleaseVar(const PP_Var& var) {
CheckThreadingPreconditions();
if (!IsVarTypeRefcounted(var.type))
return false;
return ReleaseVar(static_cast<int32_t>(var.value.as_id));
}
int32_t VarTracker::AddVarInternal(Var* var, AddVarRefMode mode) {
// If the plugin manages to create millions of strings.
if (last_var_id_ == std::numeric_limits<int32_t>::max() >> kPPIdTypeBits)
return 0;
int32_t new_id = MakeTypedId(++last_var_id_, PP_ID_TYPE_VAR);
std::pair<VarMap::iterator, bool> was_inserted =
live_vars_.insert(std::make_pair(
new_id, VarInfo(var, mode == ADD_VAR_TAKE_ONE_REFERENCE ? 1 : 0)));
// We should never insert an ID that already exists.
DCHECK(was_inserted.second);
return new_id;
}
VarTracker::VarMap::iterator VarTracker::GetLiveVar(int32_t id) {
return live_vars_.find(id);
}
int VarTracker::GetRefCountForObject(const PP_Var& plugin_object) {
CheckThreadingPreconditions();
VarMap::iterator found = GetLiveVar(plugin_object);
if (found == live_vars_.end())
return -1;
return found->second.ref_count;
}
int VarTracker::GetTrackedWithNoReferenceCountForObject(
const PP_Var& plugin_object) {
CheckThreadingPreconditions();
VarMap::iterator found = GetLiveVar(plugin_object);
if (found == live_vars_.end())
return -1;
return found->second.track_with_no_reference_count;
}
// static
bool VarTracker::IsVarTypeRefcounted(PP_VarType type) {
return type >= PP_VARTYPE_STRING;
}
VarTracker::VarMap::iterator VarTracker::GetLiveVar(const PP_Var& var) {
return live_vars_.find(static_cast<int32_t>(var.value.as_id));
}
VarTracker::VarMap::const_iterator VarTracker::GetLiveVar(const PP_Var& var)
const {
return live_vars_.find(static_cast<int32_t>(var.value.as_id));
}
PP_Var VarTracker::MakeArrayBufferPPVar(uint32_t size_in_bytes) {
CheckThreadingPreconditions();
scoped_refptr<ArrayBufferVar> array_buffer(CreateArrayBuffer(size_in_bytes));
if (!array_buffer.get())
return PP_MakeNull();
return array_buffer->GetPPVar();
}
PP_Var VarTracker::MakeArrayBufferPPVar(uint32_t size_in_bytes,
const void* data) {
CheckThreadingPreconditions();
ArrayBufferVar* array_buffer = MakeArrayBufferVar(size_in_bytes, data);
return array_buffer ? array_buffer->GetPPVar() : PP_MakeNull();
}
ArrayBufferVar* VarTracker::MakeArrayBufferVar(uint32_t size_in_bytes,
const void* data) {
CheckThreadingPreconditions();
ArrayBufferVar* array_buffer(CreateArrayBuffer(size_in_bytes));
if (!array_buffer)
return nullptr;
std::copy_n(static_cast<const uint8_t*>(data), size_in_bytes,
static_cast<uint8_t*>(array_buffer->Map()));
return array_buffer;
}
PP_Var VarTracker::MakeArrayBufferPPVar(uint32_t size_in_bytes,
base::UnsafeSharedMemoryRegion region) {
CheckThreadingPreconditions();
scoped_refptr<ArrayBufferVar> array_buffer(
CreateShmArrayBuffer(size_in_bytes, std::move(region)));
if (!array_buffer.get())
return PP_MakeNull();
return array_buffer->GetPPVar();
}
PP_Var VarTracker::MakeResourcePPVar(PP_Resource pp_resource) {
CheckThreadingPreconditions();
ResourceVar* resource_var = MakeResourceVar(pp_resource);
return resource_var ? resource_var->GetPPVar() : PP_MakeNull();
}
std::vector<PP_Var> VarTracker::GetLiveVars() {
CheckThreadingPreconditions();
std::vector<PP_Var> var_vector;
var_vector.reserve(live_vars_.size());
for (VarMap::const_iterator iter = live_vars_.begin();
iter != live_vars_.end();
++iter) {
var_vector.push_back(iter->second.var->GetPPVar());
}
return var_vector;
}
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.
iter->second.var->ResetVarID();
live_vars_.erase(iter);
return true;
}
} // namespace ppapi
Codebase Browser
chromium