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      1 // Copyright 2012 the V8 project authors. All rights reserved.
      2 // Redistribution and use in source and binary forms, with or without
      3 // modification, are permitted provided that the following conditions are
      4 // met:
      5 //
      6 //     * Redistributions of source code must retain the above copyright
      7 //       notice, this list of conditions and the following disclaimer.
      8 //     * Redistributions in binary form must reproduce the above
      9 //       copyright notice, this list of conditions and the following
     10 //       disclaimer in the documentation and/or other materials provided
     11 //       with the distribution.
     12 //     * Neither the name of Google Inc. nor the names of its
     13 //       contributors may be used to endorse or promote products derived
     14 //       from this software without specific prior written permission.
     15 //
     16 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     17 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     18 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     19 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     20 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     21 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     22 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     23 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     24 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     25 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     26 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     27 
     28 #ifndef V8_V8THREADS_H_
     29 #define V8_V8THREADS_H_
     30 
     31 namespace v8 {
     32 namespace internal {
     33 
     34 
     35 class ThreadState {
     36  public:
     37   // Returns NULL after the last one.
     38   ThreadState* Next();
     39 
     40   enum List {FREE_LIST, IN_USE_LIST};
     41 
     42   void LinkInto(List list);
     43   void Unlink();
     44 
     45   // Id of thread.
     46   void set_id(ThreadId id) { id_ = id; }
     47   ThreadId id() { return id_; }
     48 
     49   // Should the thread be terminated when it is restored?
     50   bool terminate_on_restore() { return terminate_on_restore_; }
     51   void set_terminate_on_restore(bool terminate_on_restore) {
     52     terminate_on_restore_ = terminate_on_restore;
     53   }
     54 
     55   // Get data area for archiving a thread.
     56   char* data() { return data_; }
     57 
     58  private:
     59   explicit ThreadState(ThreadManager* thread_manager);
     60   ~ThreadState();
     61 
     62   void AllocateSpace();
     63 
     64   ThreadId id_;
     65   bool terminate_on_restore_;
     66   char* data_;
     67   ThreadState* next_;
     68   ThreadState* previous_;
     69 
     70   ThreadManager* thread_manager_;
     71 
     72   friend class ThreadManager;
     73 };
     74 
     75 
     76 // Defined in isolate.h.
     77 class ThreadLocalTop;
     78 
     79 
     80 class ThreadVisitor {
     81  public:
     82   // ThreadLocalTop may be only available during this call.
     83   virtual void VisitThread(Isolate* isolate, ThreadLocalTop* top) = 0;
     84 
     85  protected:
     86   virtual ~ThreadVisitor() {}
     87 };
     88 
     89 
     90 class ThreadManager {
     91  public:
     92   void Lock();
     93   void Unlock();
     94 
     95   void ArchiveThread();
     96   bool RestoreThread();
     97   void FreeThreadResources();
     98   bool IsArchived();
     99 
    100   void Iterate(ObjectVisitor* v);
    101   void IterateArchivedThreads(ThreadVisitor* v);
    102   bool IsLockedByCurrentThread() {
    103     return mutex_owner_.Equals(ThreadId::Current());
    104   }
    105 
    106   ThreadId CurrentId();
    107 
    108   void TerminateExecution(ThreadId thread_id);
    109 
    110   // Iterate over in-use states.
    111   ThreadState* FirstThreadStateInUse();
    112   ThreadState* GetFreeThreadState();
    113 
    114  private:
    115   ThreadManager();
    116   ~ThreadManager();
    117 
    118   void DeleteThreadStateList(ThreadState* anchor);
    119 
    120   void EagerlyArchiveThread();
    121 
    122   Mutex mutex_;
    123   ThreadId mutex_owner_;
    124   ThreadId lazily_archived_thread_;
    125   ThreadState* lazily_archived_thread_state_;
    126 
    127   // In the following two lists there is always at least one object on the list.
    128   // The first object is a flying anchor that is only there to simplify linking
    129   // and unlinking.
    130   // Head of linked list of free states.
    131   ThreadState* free_anchor_;
    132   // Head of linked list of states in use.
    133   ThreadState* in_use_anchor_;
    134 
    135   Isolate* isolate_;
    136 
    137   friend class Isolate;
    138   friend class ThreadState;
    139 };
    140 
    141 
    142 } }  // namespace v8::internal
    143 
    144 #endif  // V8_V8THREADS_H_
    145