1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/ipc/glue/SharedMemory.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,111 @@
1.4 +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
1.5 + * vim: sw=2 ts=8 et :
1.6 + */
1.7 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.8 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.9 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.10 +
1.11 +#ifndef mozilla_ipc_SharedMemory_h
1.12 +#define mozilla_ipc_SharedMemory_h
1.13 +
1.14 +#include "nsDebug.h"
1.15 +#include "nsISupportsImpl.h" // NS_INLINE_DECL_REFCOUNTING
1.16 +#include "mozilla/Attributes.h"
1.17 +
1.18 +//
1.19 +// This is a low-level wrapper around platform shared memory. Don't
1.20 +// use it directly; use Shmem allocated through IPDL interfaces.
1.21 +//
1.22 +namespace {
1.23 +enum Rights {
1.24 + RightsNone = 0,
1.25 + RightsRead = 1 << 0,
1.26 + RightsWrite = 1 << 1
1.27 +};
1.28 +}
1.29 +
1.30 +namespace mozilla {
1.31 +namespace ipc {
1.32 +
1.33 +class SharedMemory
1.34 +{
1.35 +public:
1.36 + virtual ~SharedMemory()
1.37 + {
1.38 + MOZ_COUNT_DTOR(SharedMemory);
1.39 + Unmapped();
1.40 + Destroyed();
1.41 + }
1.42 +
1.43 + enum SharedMemoryType {
1.44 + TYPE_BASIC,
1.45 + TYPE_SYSV,
1.46 + TYPE_UNKNOWN
1.47 + };
1.48 +
1.49 + size_t Size() const { return mMappedSize; }
1.50 +
1.51 + virtual void* memory() const = 0;
1.52 +
1.53 + virtual bool Create(size_t size) = 0;
1.54 + virtual bool Map(size_t nBytes) = 0;
1.55 +
1.56 + virtual SharedMemoryType Type() const = 0;
1.57 +
1.58 + void
1.59 + Protect(char* aAddr, size_t aSize, int aRights)
1.60 + {
1.61 + char* memStart = reinterpret_cast<char*>(memory());
1.62 + if (!memStart)
1.63 + NS_RUNTIMEABORT("SharedMemory region points at NULL!");
1.64 + char* memEnd = memStart + Size();
1.65 +
1.66 + char* protStart = aAddr;
1.67 + if (!protStart)
1.68 + NS_RUNTIMEABORT("trying to Protect() a NULL region!");
1.69 + char* protEnd = protStart + aSize;
1.70 +
1.71 + if (!(memStart <= protStart
1.72 + && protEnd <= memEnd))
1.73 + NS_RUNTIMEABORT("attempt to Protect() a region outside this SharedMemory");
1.74 +
1.75 + // checks alignment etc.
1.76 + SystemProtect(aAddr, aSize, aRights);
1.77 + }
1.78 +
1.79 + NS_INLINE_DECL_REFCOUNTING(SharedMemory)
1.80 +
1.81 + static void SystemProtect(char* aAddr, size_t aSize, int aRights);
1.82 + static size_t SystemPageSize();
1.83 + static size_t PageAlignedSize(size_t aSize);
1.84 +
1.85 +protected:
1.86 + SharedMemory();
1.87 +
1.88 + // Implementations should call these methods on shmem usage changes,
1.89 + // but *only if* the OS-specific calls are known to have succeeded.
1.90 + // The methods are expected to be called in the pattern
1.91 + //
1.92 + // Created (Mapped Unmapped)* Destroy
1.93 + //
1.94 + // but this isn't checked.
1.95 + void Created(size_t aNBytes);
1.96 + void Mapped(size_t aNBytes);
1.97 + void Unmapped();
1.98 + void Destroyed();
1.99 +
1.100 + // The size of the shmem region requested in Create(), if
1.101 + // successful. SharedMemory instances that are opened from a
1.102 + // foreign handle have an alloc size of 0, even though they have
1.103 + // access to the alloc-size information.
1.104 + size_t mAllocSize;
1.105 + // The size of the region mapped in Map(), if successful. All
1.106 + // SharedMemorys that are mapped have a non-zero mapped size.
1.107 + size_t mMappedSize;
1.108 +};
1.109 +
1.110 +} // namespace ipc
1.111 +} // namespace mozilla
1.112 +
1.113 +
1.114 +#endif // ifndef mozilla_ipc_SharedMemory_h
