LCOV - code coverage report
Current view: directory - objdir/dist/include/mozilla/ipc - SharedMemory.h (source / functions) Found Hit Coverage
Test: app.info Lines: 17 0 0.0 %
Date: 2012-06-02 Functions: 6 0 0.0 %

       1                 : /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
       2                 :  * vim: sw=2 ts=8 et :
       3                 :  */
       4                 : /* ***** BEGIN LICENSE BLOCK *****
       5                 :  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
       6                 :  *
       7                 :  * The contents of this file are subject to the Mozilla Public License Version
       8                 :  * 1.1 (the "License"); you may not use this file except in compliance with
       9                 :  * the License. You may obtain a copy of the License at
      10                 :  * http://www.mozilla.org/MPL/
      11                 :  *
      12                 :  * Software distributed under the License is distributed on an "AS IS" basis,
      13                 :  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
      14                 :  * for the specific language governing rights and limitations under the
      15                 :  * License.
      16                 :  *
      17                 :  * The Original Code is Mozilla IPC.
      18                 :  *
      19                 :  * The Initial Developer of the Original Code is
      20                 :  *   The Mozilla Foundation
      21                 :  * Portions created by the Initial Developer are Copyright (C) 2009-2010
      22                 :  * the Initial Developer. All Rights Reserved.
      23                 :  *
      24                 :  * Contributor(s):
      25                 :  *
      26                 :  * Alternatively, the contents of this file may be used under the terms of
      27                 :  * either the GNU General Public License Version 2 or later (the "GPL"), or
      28                 :  * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
      29                 :  * in which case the provisions of the GPL or the LGPL are applicable instead
      30                 :  * of those above. If you wish to allow use of your version of this file only
      31                 :  * under the terms of either the GPL or the LGPL, and not to allow others to
      32                 :  * use your version of this file under the terms of the MPL, indicate your
      33                 :  * decision by deleting the provisions above and replace them with the notice
      34                 :  * and other provisions required by the GPL or the LGPL. If you do not delete
      35                 :  * the provisions above, a recipient may use your version of this file under
      36                 :  * the terms of any one of the MPL, the GPL or the LGPL.
      37                 :  *
      38                 :  * ***** END LICENSE BLOCK ***** */
      39                 : 
      40                 : #ifndef mozilla_ipc_SharedMemory_h
      41                 : #define mozilla_ipc_SharedMemory_h
      42                 : 
      43                 : #include "nsDebug.h"
      44                 : #include "nsISupportsImpl.h"    // NS_INLINE_DECL_REFCOUNTING
      45                 : 
      46                 : //
      47                 : // This is a low-level wrapper around platform shared memory.  Don't
      48                 : // use it directly; use Shmem allocated through IPDL interfaces.
      49                 : //
      50                 : namespace {
      51                 : enum Rights {
      52                 :   RightsNone = 0,
      53                 :   RightsRead = 1 << 0,
      54                 :   RightsWrite = 1 << 1
      55                 : };
      56                 : }
      57                 : 
      58                 : namespace mozilla {
      59                 : namespace ipc {
      60                 : 
      61                 : class SharedMemory
      62                 : {
      63                 : public:
      64                 :   enum SharedMemoryType {
      65                 :     TYPE_BASIC,
      66                 :     TYPE_SYSV,
      67                 :     TYPE_UNKNOWN
      68                 :   };
      69                 : 
      70               0 :   virtual ~SharedMemory() { Unmapped(); Destroyed(); }
      71                 : 
      72               0 :   size_t Size() const { return mMappedSize; }
      73                 : 
      74                 :   virtual void* memory() const = 0;
      75                 : 
      76                 :   virtual bool Create(size_t size) = 0;
      77                 :   virtual bool Map(size_t nBytes) = 0;
      78                 : 
      79                 :   virtual SharedMemoryType Type() const = 0;
      80                 : 
      81                 :   void
      82               0 :   Protect(char* aAddr, size_t aSize, int aRights)
      83                 :   {
      84               0 :     char* memStart = reinterpret_cast<char*>(memory());
      85               0 :     if (!memStart)
      86               0 :       NS_RUNTIMEABORT("SharedMemory region points at NULL!");
      87               0 :     char* memEnd = memStart + Size();
      88                 : 
      89               0 :     char* protStart = aAddr;
      90               0 :     if (!protStart)
      91               0 :       NS_RUNTIMEABORT("trying to Protect() a NULL region!");
      92               0 :     char* protEnd = protStart + aSize;
      93                 : 
      94               0 :     if (!(memStart <= protStart
      95               0 :           && protEnd <= memEnd))
      96               0 :       NS_RUNTIMEABORT("attempt to Protect() a region outside this SharedMemory");
      97                 : 
      98                 :     // checks alignment etc.
      99               0 :     SystemProtect(aAddr, aSize, aRights);
     100               0 :   }
     101                 : 
     102               0 :   NS_INLINE_DECL_REFCOUNTING(SharedMemory)
     103                 : 
     104                 :   static void SystemProtect(char* aAddr, size_t aSize, int aRights);
     105                 :   static size_t SystemPageSize();
     106                 :   static size_t PageAlignedSize(size_t aSize);
     107                 : 
     108                 : protected:
     109                 :   SharedMemory();
     110                 : 
     111                 :   // Implementations should call these methods on shmem usage changes,
     112                 :   // but *only if* the OS-specific calls are known to have succeeded.
     113                 :   // The methods are expected to be called in the pattern
     114                 :   //
     115                 :   //   Created (Mapped Unmapped)* Destroy
     116                 :   //
     117                 :   // but this isn't checked.
     118                 :   void Created(size_t aNBytes);
     119                 :   void Mapped(size_t aNBytes);
     120                 :   void Unmapped();
     121                 :   void Destroyed();
     122                 : 
     123                 :   // The size of the shmem region requested in Create(), if
     124                 :   // successful.  SharedMemory instances that are opened from a
     125                 :   // foreign handle have an alloc size of 0, even though they have
     126                 :   // access to the alloc-size information.
     127                 :   size_t mAllocSize;
     128                 :   // The size of the region mapped in Map(), if successful.  All
     129                 :   // SharedMemorys that are mapped have a non-zero mapped size.
     130                 :   size_t mMappedSize;
     131                 : };
     132                 : 
     133                 : } // namespace ipc
     134                 : } // namespace mozilla
     135                 : 
     136                 : 
     137                 : #endif // ifndef mozilla_ipc_SharedMemory_h

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