hphp/runtime/base/root-map.h

   1 /*
   2    +----------------------------------------------------------------------+
   3    | HipHop for PHP                                                       |
   4    +----------------------------------------------------------------------+
   5    | Copyright (c) 2010-present Facebook, Inc. (http://www.facebook.com)  |
   6    +----------------------------------------------------------------------+
   7    | This source file is subject to version 3.01 of the PHP license,      |
   8    | that is bundled with this package in the file LICENSE, and is        |
   9    | available through the world-wide-web at the following url:           |
  10    | http://www.php.net/license/3_01.txt                                  |
  11    | If you did not receive a copy of the PHP license and are unable to   |
  12    | obtain it through the world-wide-web, please send a note to          |
  13    | license@php.net so we can mail you a copy immediately.               |
  14    +----------------------------------------------------------------------+
  15 */
  16
  17 #ifndef incl_HPHP_ROOT_MAP_H_
  18 #define incl_HPHP_ROOT_MAP_H_
  19
  20 #include "hphp/runtime/base/req-containers.h"
  21 #include "hphp/runtime/base/req-ptr.h"
  22
  23 namespace HPHP {
  24
  25 /*
  26  * RootMap wraps a simple id->object hashtable, useful for extensions
  27  * that need pass 'handles' to objects or resources into 3rd party apis
  28  * masked as integers or void* pointers. The map is intended to be a
  29  * field of a thread local, where it will be automatically scanned by
  30  * the gc, and must be reset() between requests.
  31  */
  32 template<class T> struct RootMap {
  33   using RootId = uintptr_t;
  34   using Map = req::hash_map<RootId,req::ptr<T>>;
  35
  36   RootId addRoot(req::ptr<T>&& ptr) {
  37     assertx(ptr);
  38     const RootId tok = ptr->getId();
  39     getMap().emplace(tok, std::move(ptr));
  40     return tok;
  41   }
  42
  43   RootId addRoot(const req::ptr<T>& ptr) {
  44     assertx(ptr);
  45     auto tok = ptr->getId();
  46     getMap()[tok] = ptr;
  47     return tok;
  48     static_assert(sizeof(tok) <= sizeof(RootId), "");
  49   }
  50
  51   req::ptr<T> lookupRoot(const void* vp) const {
  52     return lookupRoot(reinterpret_cast<RootId>(vp));
  53   }
  54
  55   req::ptr<T> lookupRoot(RootId tok) const {
  56     if (!m_map) return nullptr;
  57     auto& map = *m_map;
  58     auto it = map.find(tok);
  59     return it != map.end() ? unsafe_cast_or_null<T>(it->second) : nullptr;
  60   }
  61
  62   req::ptr<T> removeRoot(RootId tok) {
  63     if (m_map) {
  64       auto it = m_map->find(tok);
  65       if (it != m_map->end()) {
  66         auto ptr = std::move(it->second);
  67         m_map->erase(it);
  68         return unsafe_cast_or_null<T>(ptr);
  69       }
  70     }
  71     return nullptr;
  72   }
  73
  74   req::ptr<T> removeRoot(const void* vp) {
  75     return removeRoot(reinterpret_cast<RootId>(vp));
  76   }
  77
  78   bool removeRoot(const req::ptr<T>& ptr) {
  79     return removeRoot(ptr->getId()) != nullptr;
  80   }
  81
  82   bool removeRoot(const T* ptr) {
  83     return removeRoot(ptr->getId()) != nullptr;
  84   }
  85
  86   void reset() {
  87     m_map = nullptr;
  88   }
  89
  90 private:
  91   Map& getMap() {
  92     if (UNLIKELY(!m_map)) {
  93       m_map = req::make_raw<Map>();
  94     }
  95     return *m_map;
  96   }
  97   Map* m_map{nullptr};
  98 };
  99
 100 }
 101 #endif