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 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

 /* vim: set ts=8 sts=2 et sw=2 tw=80: */

 /* This Source Code Form is subject to the terms of the Mozilla Public

  * License, v. 2.0. If a copy of the MPL was not distributed with this

  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

 #ifndef AutoObjectMapper_h

 #define AutoObjectMapper_h

 #include <string>

 #include "mozilla/Attributes.h"

 #include "PlatformMacros.h"

 // A (nearly-) RAII class that maps an object in and then unmaps it on

 // destruction.  This base class version uses the "normal" POSIX

 // functions: open, fstat, close, mmap, munmap.

 class MOZ_STACK_CLASS AutoObjectMapperPOSIX {

 public:

   // The constructor does not attempt to map the file, because that

   // might fail.  Instead, once the object has been constructed,

   // call Map() to attempt the mapping.  There is no corresponding

   // Unmap() since the unmapping is done in the destructor.  Failure

   // messages are sent to |aLog|.

   AutoObjectMapperPOSIX(void(*aLog)(const char*));

   // Unmap the file on destruction of this object.

   ~AutoObjectMapperPOSIX();

   // Map |fileName| into the address space and return the mapping

   // extents.  If the file is zero sized this will fail.  The file is

   // mapped read-only and private.  Returns true iff the mapping

   // succeeded, in which case *start and *length hold its extent.

   // Once a call to Map succeeds, all subsequent calls to it will

   // fail.

   bool Map(/*OUT*/void** start, /*OUT*/size_t* length, std::string fileName);

 protected:

   // If we are currently holding a mapped object, these record the

   // mapped address range.

   void*  mImage;

   size_t mSize;

   // A logging sink, for complaining about mapping failures.

   void (*mLog)(const char*);

 private:

   // Are we currently holding a mapped object?  This is private to

   // the base class.  Derived classes need to have their own way to

   // track whether they are holding a mapped object.

   bool mIsMapped;

   // Disable copying and assignment.

   AutoObjectMapperPOSIX(const AutoObjectMapperPOSIX&);

   AutoObjectMapperPOSIX& operator=(const AutoObjectMapperPOSIX&);

   // Disable heap allocation of this class.

   void* operator new(size_t);

   void* operator new[](size_t);

   void  operator delete(void*);

   void  operator delete[](void*);

 };

 #if defined(SPS_OS_android) && !defined(MOZ_WIDGET_GONK)

 // This is a variant of AutoObjectMapperPOSIX suitable for use in

 // conjunction with faulty.lib on Android.  How it behaves depends on

 // the name of the file to be mapped.  There are three possible cases:

 //

 // (1) /foo/bar/xyzzy/blah.apk!/libwurble.so

 //     We hand it as-is to faulty.lib and let it fish the relevant

 //     bits out of the APK.

 //

 // (2) libmozglue.so

 //     This is part of the Fennec installation, but is not in the

 //     APK.  Instead we have to figure out the installation path

 //     and look for it there.  Because of faulty.lib limitations,

 //     we have to use regular open/mmap instead of faulty.lib.

 //

 // (3) libanythingelse.so

 //     faulty.lib assumes this is a system library, and prepends

 //     "/system/lib/" to the path.  So as in (1), we can give it

 //     as-is to faulty.lib.

 //

 // Hence (1) and (3) require special-casing here.  Case (2) simply

 // hands the problem to the parent class.

 class MOZ_STACK_CLASS AutoObjectMapperFaultyLib : public AutoObjectMapperPOSIX {

 public:

   AutoObjectMapperFaultyLib(void(*aLog)(const char*));

   ~AutoObjectMapperFaultyLib();

   bool Map(/*OUT*/void** start, /*OUT*/size_t* length, std::string fileName);

 private:

   // faulty.lib requires us to maintain an abstract handle that can be

   // used later to unmap the area.  If this is non-NULL, it is assumed

   // that unmapping is to be done by faulty.lib.  Otherwise it goes

   // via the normal mechanism.

   void* mHdl;

   // Disable copying and assignment.

   AutoObjectMapperFaultyLib(const AutoObjectMapperFaultyLib&);

   AutoObjectMapperFaultyLib& operator=(const AutoObjectMapperFaultyLib&);

   // Disable heap allocation of this class.

   void* operator new(size_t);

   void* operator new[](size_t);

   void  operator delete(void*);

   void  operator delete[](void*);

 };

 #endif // defined(SPS_OS_android) && !defined(MOZ_WIDGET_GONK)

 #endif // AutoObjectMapper_h