michael@0: /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
michael@0: /* vim: set ts=8 sts=2 et sw=2 tw=80: */
michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #ifndef AutoObjectMapper_h
michael@0: #define AutoObjectMapper_h
michael@0: 
michael@0: #include <string>
michael@0: 
michael@0: #include "mozilla/Attributes.h"
michael@0: #include "PlatformMacros.h"
michael@0: 
michael@0: // A (nearly-) RAII class that maps an object in and then unmaps it on
michael@0: // destruction.  This base class version uses the "normal" POSIX
michael@0: // functions: open, fstat, close, mmap, munmap.
michael@0: 
michael@0: class MOZ_STACK_CLASS AutoObjectMapperPOSIX {
michael@0: public:
michael@0:   // The constructor does not attempt to map the file, because that
michael@0:   // might fail.  Instead, once the object has been constructed,
michael@0:   // call Map() to attempt the mapping.  There is no corresponding
michael@0:   // Unmap() since the unmapping is done in the destructor.  Failure
michael@0:   // messages are sent to |aLog|.
michael@0:   AutoObjectMapperPOSIX(void(*aLog)(const char*));
michael@0: 
michael@0:   // Unmap the file on destruction of this object.
michael@0:   ~AutoObjectMapperPOSIX();
michael@0: 
michael@0:   // Map |fileName| into the address space and return the mapping
michael@0:   // extents.  If the file is zero sized this will fail.  The file is
michael@0:   // mapped read-only and private.  Returns true iff the mapping
michael@0:   // succeeded, in which case *start and *length hold its extent.
michael@0:   // Once a call to Map succeeds, all subsequent calls to it will
michael@0:   // fail.
michael@0:   bool Map(/*OUT*/void** start, /*OUT*/size_t* length, std::string fileName);
michael@0: 
michael@0: protected:
michael@0:   // If we are currently holding a mapped object, these record the
michael@0:   // mapped address range.
michael@0:   void*  mImage;
michael@0:   size_t mSize;
michael@0: 
michael@0:   // A logging sink, for complaining about mapping failures.
michael@0:   void (*mLog)(const char*);
michael@0: 
michael@0: private:
michael@0:   // Are we currently holding a mapped object?  This is private to
michael@0:   // the base class.  Derived classes need to have their own way to
michael@0:   // track whether they are holding a mapped object.
michael@0:   bool mIsMapped;
michael@0: 
michael@0:   // Disable copying and assignment.
michael@0:   AutoObjectMapperPOSIX(const AutoObjectMapperPOSIX&);
michael@0:   AutoObjectMapperPOSIX& operator=(const AutoObjectMapperPOSIX&);
michael@0:   // Disable heap allocation of this class.
michael@0:   void* operator new(size_t);
michael@0:   void* operator new[](size_t);
michael@0:   void  operator delete(void*);
michael@0:   void  operator delete[](void*);
michael@0: };
michael@0: 
michael@0: 
michael@0: #if defined(SPS_OS_android) && !defined(MOZ_WIDGET_GONK)
michael@0: // This is a variant of AutoObjectMapperPOSIX suitable for use in
michael@0: // conjunction with faulty.lib on Android.  How it behaves depends on
michael@0: // the name of the file to be mapped.  There are three possible cases:
michael@0: //
michael@0: // (1) /foo/bar/xyzzy/blah.apk!/libwurble.so
michael@0: //     We hand it as-is to faulty.lib and let it fish the relevant
michael@0: //     bits out of the APK.
michael@0: //
michael@0: // (2) libmozglue.so
michael@0: //     This is part of the Fennec installation, but is not in the
michael@0: //     APK.  Instead we have to figure out the installation path
michael@0: //     and look for it there.  Because of faulty.lib limitations,
michael@0: //     we have to use regular open/mmap instead of faulty.lib.
michael@0: //
michael@0: // (3) libanythingelse.so
michael@0: //     faulty.lib assumes this is a system library, and prepends
michael@0: //     "/system/lib/" to the path.  So as in (1), we can give it
michael@0: //     as-is to faulty.lib.
michael@0: //
michael@0: // Hence (1) and (3) require special-casing here.  Case (2) simply
michael@0: // hands the problem to the parent class.
michael@0: 
michael@0: class MOZ_STACK_CLASS AutoObjectMapperFaultyLib : public AutoObjectMapperPOSIX {
michael@0: public:
michael@0:   AutoObjectMapperFaultyLib(void(*aLog)(const char*));
michael@0: 
michael@0:   ~AutoObjectMapperFaultyLib();
michael@0: 
michael@0:   bool Map(/*OUT*/void** start, /*OUT*/size_t* length, std::string fileName);
michael@0: 
michael@0: private:
michael@0:   // faulty.lib requires us to maintain an abstract handle that can be
michael@0:   // used later to unmap the area.  If this is non-NULL, it is assumed
michael@0:   // that unmapping is to be done by faulty.lib.  Otherwise it goes
michael@0:   // via the normal mechanism.
michael@0:   void* mHdl;
michael@0: 
michael@0:   // Disable copying and assignment.
michael@0:   AutoObjectMapperFaultyLib(const AutoObjectMapperFaultyLib&);
michael@0:   AutoObjectMapperFaultyLib& operator=(const AutoObjectMapperFaultyLib&);
michael@0:   // Disable heap allocation of this class.
michael@0:   void* operator new(size_t);
michael@0:   void* operator new[](size_t);
michael@0:   void  operator delete(void*);
michael@0:   void  operator delete[](void*);
michael@0: };
michael@0: 
michael@0: #endif // defined(SPS_OS_android) && !defined(MOZ_WIDGET_GONK)
michael@0: 
michael@0: #endif // AutoObjectMapper_h