Edwin Smith
90 linhas
3.1 KiB
C++
90 linhas
3.1 KiB
C++
/*
|
|
+----------------------------------------------------------------------+
|
|
| HipHop for PHP |
|
|
+----------------------------------------------------------------------+
|
|
| Copyright (c) 2010-2013 Facebook, Inc. (http://www.facebook.com) |
|
|
+----------------------------------------------------------------------+
|
|
| This source file is subject to version 3.01 of the PHP license, |
|
|
| that is bundled with this package in the file LICENSE, and is |
|
|
| available through the world-wide-web at the following url: |
|
|
| http://www.php.net/license/3_01.txt |
|
|
| If you did not receive a copy of the PHP license and are unable to |
|
|
| obtain it through the world-wide-web, please send a note to |
|
|
| license@php.net so we can mail you a copy immediately. |
|
|
+----------------------------------------------------------------------+
|
|
*/
|
|
|
|
#include "hphp/runtime/base/shared_string.h"
|
|
|
|
namespace HPHP {
|
|
///////////////////////////////////////////////////////////////////////////////
|
|
|
|
SharedStringData::InternMap SharedStringData::s_intern;
|
|
|
|
SharedStringData::SharedStringData(const std::string &data) : m_data(data) {
|
|
m_count = 1;
|
|
}
|
|
|
|
int SharedStringData::decRefCount() const {
|
|
assert(m_count > 0);
|
|
int cur = m_count.fetch_and_decrement() - 1;
|
|
if (cur == 0) {
|
|
// Only left in intern map. While this data is still in the
|
|
// the map we consider this data dying. All new Creates will
|
|
// overwrite the SharedStringData* in the slot and not use this one.
|
|
InternMap::accessor acc;
|
|
bool found = s_intern.find(acc, m_data);
|
|
assert(m_count == 0);
|
|
// May not be found or may not be acc->second if other thread overwrote.
|
|
// Safe to just delete self.
|
|
if (found && acc->second == this) {
|
|
s_intern.erase(acc);
|
|
}
|
|
return 0;
|
|
}
|
|
return 1;
|
|
}
|
|
|
|
void SharedStringData::release() {
|
|
delete this;
|
|
}
|
|
|
|
const std::string &SharedStringData::getString() const {
|
|
return m_data;
|
|
}
|
|
|
|
void SharedStringData::Create(InternMap::accessor &acc,
|
|
const std::string &data) {
|
|
if (s_intern.insert(acc, data)) {
|
|
acc->second = new SharedStringData(acc->first);
|
|
return;
|
|
}
|
|
// Danger is now that the data is dying. We must not acquire a reference
|
|
// if it in that state.
|
|
while (true) {
|
|
int cur = acc->second->m_count;
|
|
if (cur == 0) {
|
|
acc->second = new SharedStringData(acc->first);
|
|
break;
|
|
}
|
|
// Never change refcount of 0 to refcount of 1, impossible
|
|
// to revive a dying SharedStringData.
|
|
if (acc->second->m_count.compare_and_swap(cur + 1, cur) == cur) {
|
|
break;
|
|
}
|
|
// Other thread must have inc/dec ref'd since we got cur
|
|
}
|
|
}
|
|
|
|
SharedString &SharedString::operator=(const std::string &data) {
|
|
reset();
|
|
SharedStringData::InternMap::accessor acc;
|
|
SharedStringData::Create(acc, data);
|
|
// Ref count already incremented in Create
|
|
m_px = acc->second;
|
|
return *this;
|
|
}
|
|
|
|
///////////////////////////////////////////////////////////////////////////////
|
|
}
|