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// Copyright (C) 2006-2007 David Sugar, Tycho Softworks.
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
/**
* Support for memory mapped objects.
* Memory mapped objects can be used to publish information so that it may be
* accessible directly by external programs. The mapped memory objects will
* usually be built as a vector vector or reusable type factory, in the latter
* case using the allocated shared memory block itself as a local heap. A
* simple template can be used to view the mapped contents that have been
* published by another process.
* @file sipwitch/mapped.h
*/
#ifndef _SIPWITCH_MAPPED_H_
#define _SIPWITCH_MAPPED_H_
#ifndef _UCOMMON_LINKED_H_
#include <ucommon/linked.h>
#endif
#ifndef _UCOMMON_THREAD_H_
#include <ucommon/thread.h>
#endif
#ifndef _UCOMMON_STRING_H_
#include <ucommon/string.h>
#endif
#ifndef _MSWINDOWS_
#include <signal.h>
#endif
#ifndef _SIPWITCH_NAMESPACE_H_
#include <sipwitch/namespace.h>
#endif
NAMESPACE_SIPWITCH
using namespace UCOMMON_NAMESPACE;
/**
* Construct or access a named section of memory. A logical name is used
* which might map to something that is invoked from a call like shm_open
* or a named w32 mapped swap segment. This is meant to support mapping a
* vector onto shared memory and is often used as a supporting class for our
* shared memory access templates.
* @author David Sugar <dyfet@gnutelephony.org>
*/
class __EXPORT MappedMemory
{
private:
size_t mapsize;
caddr_t map;
fd_t fd;
protected:
size_t size, used;
MappedMemory();
/**
* Supporting function to construct a new or access an existing
* shared memory segment. Used by primary constructors.
* @param name of segment to create or access.
* @param size of segment if creating new. Use 0 for read-only access.
*/
void create(const char *name, size_t size = (size_t)0);
/**
* Handler to invoke in derived class when accessing outside the
* shared memory segment boundry.
*/
virtual void fault(void);
public:
/**
* Construct a read/write access mapped shared segment of memory of a
* known size. This constructs a new memory segment.
* @param name of segment.
* @param size of segment.
*/
MappedMemory(const char *name, size_t size);
/**
* Provide read-only mapped access to an existing named shared memory
* segment. The size of the map is found by the size of the already
* existing segment.
* @param name of existing segment.
*/
MappedMemory(const char *name);
/**
* Unmap memory segment.
*/
virtual ~MappedMemory();
/**
* Unmap memory segment.
*/
void release(void);
/**
* Destroy a previously existing memory segment under the specified name.
* This is used both before creating a new one, and after a publishing
* process unmaps the segment it created.
* @param name of segment to remove.
*/
static void remove(const char *name);
/**
* Test if map active.
* @return true if active map.
*/
inline operator bool() const
{return (size != 0);};
/**
* Test if map is inactive.
* @return true if map inactive.
*/
inline bool operator!() const
{return (size == 0);};
/**
* Extend size of managed heap on shared memory segment. This does not
* change the size of the mapped segment in any way, only that of any
* heap space that is being allocated and used from the mapped segment.
* @return start of space from map.
* @param size of space requested. Will fault if past end of segment.
*/
void *sbrk(size_t size);
/**
* Get memory from a specific offset within the mapped memory segment.
* @param offset from start of segment. Will fault if past end.
* @return address of offset.
*/
void *offset(size_t offset);
/**
* Get size of mapped segment.
* @return size of mapped segment.
*/
inline size_t len(void)
{return size;};
/**
* Get starting address of mapped segment.
* @return starting address of mapped segment.
*/
inline caddr_t getStart(void)
{return map;};
};
/**
* Map a reusable allocator over a named shared memory segment. This may be
* used to form a resource bound fixed size managed heap in shared memory.
* The request can either be fullfilled from the object reuse pool or from a
* new section of memory, and if all memory in the segment has been exhausted,
* it can wait until more objects are returned by another thread to the reuse
* pool.
* @author David Sugar <dyfet@gnutelephony.org>
*/
class __EXPORT MappedReuse : protected ReusableAllocator, protected MappedMemory
{
private:
unsigned objsize;
unsigned reading;
mutex_t mutex;
protected:
MappedReuse(size_t osize);
inline void create(const char *fname, unsigned count)
{MappedMemory::create(fname, count * objsize);};
public:
/**
* Construct a named memory segment for use with managed fixed size
* reusable objects. The segment is created as writable. There is no
* read-only version of mapped reuse since the mapped segment can be read
* by another process directly as a mapped read-only vector. The actual
* mapped type will be derived from ReusableObject to meet the needs of
* the reusable allocator. The templated version should be used to
* assure type correctness rather than using this class directly.
* @param name of shared memory segment.
* @param size of the object type being mapped.
* @param count of the maximum number of active mapped objects.
*/
MappedReuse(const char *name, size_t size, unsigned count);
/**
* Check whether there are objects available to be allocated.
* @return true if objects are available.
*/
bool avail(void);
/**
* Request a reusable object from the free list or mapped space.
* @return free object or NULL if pool is exhausted.
*/
ReusableObject *request(void);
/**
* Request a reusable object from the free list or mapped space.
* This method blocks until an object becomes available.
* @return free object.
*/
ReusableObject *get(void);
/**
* Request a reusable object from the free list or mapped space.
* This method blocks until an object becomes available or the
* timeout has expired.
* @param timeout to wait in milliseconds.
* @return free object or NULL if timeout.
*/
ReusableObject *getTimed(timeout_t timeout);
/**
* Used to get an object from the reuse pool when the mutex lock is
* already held.
* @return object from pool or NULL if exhausted.
*/
ReusableObject *getLocked(void);
/**
* Used to return an object to the reuse pool when the mutex lock is
* already held.
* @param object being returned.
*/
void removeLocked(ReusableObject *object);
};
/**
* Template class to map typed vector into shared memory. This is used to
* construct a typed read/write vector of objects that are held in a named
* shared memory segment.
* @author David Sugar <dyfet@gnutelephony.org>
*/
template <class T>
class mapped_array : public MappedMemory
{
protected:
inline mapped_array() : MappedMemory() {};
inline void create(const char *fn, unsigned members)
{MappedMemory::create(fn, members * sizeof(T));};
public:
/**
* Construct mapped vector array of typed objects. This is constructed
* for read/write access. mapped_view is used in all cases for read-only
* access to mapped data. Member objects are linearly allocated from
* the shared memory segment, or may simply be directly accessed by offset.
* @param name of mapped segment to construct.
* @param number of objects in the mapped vector.
*/
inline mapped_array(const char *name, unsigned number) :
MappedMemory(name, number * sizeof(T)) {};
/**
* Initialize typed data in mapped array. Assumes default constructor
* for type.
*/
inline void initialize(void)
{new((caddr_t)offset(0)) T[size / sizeof(T)];};
/**
* Add mapped space while holding lock for one object.
* @return address of object.
*/
inline void *addLock(void)
{return sbrk(sizeof(T));};
/**
* Get typed pointer to member object of vector in mapped segment.
* @param member to access.
* @return typed pointer or NULL if past end of array.
*/
inline T *operator()(unsigned member)
{return static_cast<T*>(offset(member * sizeof(T)));}
/**
* Allocate mapped space for one object.
* @return address of object.
*/
inline T *operator()(void)
{return static_cast<T*>(sbrk(sizeof(T)));};
/**
* Reference typed object of vector in mapped segment.
* @param member to access.
* @return typed reference.
*/
inline T &operator[](unsigned member)
{return *(operator()(member));};
/**
* Get member size of typed objects that can be held in mapped vector.
* @return members mapped in segment.
*/
inline unsigned getSize(void)
{return (unsigned)(size / sizeof(T));};
};
/**
* Template class to map typed resusble objects into shared memory heap.
* This is used to construct a read/write heap of objects that are held in a
* named shared memory segment. Member objects are allocated from a reusable
* heap but are stored in the shared memory segment as a vector.
* @author David Sugar <dyfet@gnutelephony.org>
*/
template <class T>
class mapped_reuse : public MappedReuse
{
protected:
inline mapped_reuse() :
MappedReuse(sizeof(T)) {};
public:
/**
* Construct mapped reuse array of typed objects. This is constructed
* for read/write access. mapped_view is used in all cases for read-only
* access to mapped data.
* @param name of mapped segment to construct.
* @param number of objects in the mapped vector.
*/
inline mapped_reuse(const char *name, unsigned number) :
MappedReuse(name, sizeof(T), number) {};
/**
* Initialize typed data in mapped array. Assumes default constructor
* for type.
*/
inline void initialize(void)
{new((caddr_t)pos(0)) T[size / sizeof(T)];};
/**
* Check whether there are typed objects available to be allocated.
* @return true if objects are available.
*/
inline operator bool()
{return MappedReuse::avail();};
/**
* Check whether there are typed objects available to be allocated.
* @return true if no more typed objects are available.
*/
inline bool operator!()
{return !MappedReuse::avail();};
/**
* Request a typed reusable object from the free list or mapped space.
* This method blocks until an object becomes available.
* @return free object.
*/
inline operator T*()
{return mapped_reuse::get();};
/**
* Request a typed reusable object from the free list or mapped space by
* pointer reference. This method blocks until an object becomes available.
* @return free object.
*/
inline T* operator*()
{return mapped_reuse::get();};
/**
* Get typed object from a specific member offset within the mapped segment.
* @param member offset from start of segment. Will fault if past end.
* @return typed object pointer.
*/
inline T *pos(size_t member)
{return static_cast<T*>(MappedReuse::offset(member * sizeof(T)));};
/**
* Request a typed reusable object from the free list or mapped space.
* This method blocks until an object becomes available.
* @return free typed object.
*/
inline T *get(void)
{return static_cast<T*>(MappedReuse::get());};
/**
* Request a typed reusable object from the free list or mapped space.
* This method blocks until an object becomes available from another
* thread or the timeout expires.
* @param timeout in milliseconds.
* @return free typed object.
*/
inline T *getTimed(timeout_t timeout)
{return static_cast<T*>(MappedReuse::getTimed(timeout));};
/**
* Request a typed reusable object from the free list or mapped space.
* This method does not block or wait.
* @return free typed object if available or NULL.
*/
inline T *request(void)
{return static_cast<T*>(MappedReuse::request());};
/**
* Used to return a typed object to the reuse pool when the mutex lock is
* already held.
* @param object being returned.
*/
inline void removeLocked(T *object)
{MappedReuse::removeLocked(object);};
/**
* Used to get a typed object from the reuse pool when the mutex lock is
* already held.
* @return typed object from pool or NULL if exhausted.
*/
inline T *getLocked(void)
{return static_cast<T*>(MappedReuse::getLocked());};
/**
* Used to release a typed object back to the reuse typed object pool.
* @param object being released.
*/
inline void release(T *object)
{ReusableAllocator::release(object);};
};
/**
* Class to access a named mapped segment published from another process.
* This offers a simple typed vector interface to access the shared memory
* segment in read-only mode.
* @author David Sugar <dyfet@gnutelephony.org>
*/
template <class T>
class mapped_view : protected MappedMemory
{
public:
/**
* Map existing named memory segment. The size of the map is derived
* from the existing map alone.
* @param name of memory segment to map.
*/
inline mapped_view(const char *name) :
MappedMemory(name) {};
/**
* Access typed member object in the mapped segment.
* @param member to access.
* @return typed object pointer.
*/
inline volatile const T *operator()(unsigned member)
{return static_cast<const T*>(offset(member * sizeof(T)));}
/**
* Reference typed member object in the mapped segment.
* @param member to access.
* @return typed object reference.
*/
inline volatile const T &operator[](unsigned member)
{return *(operator()(member));};
/**
* Get count of typed member objects held in this map.
* @return count of typed member objects.
*/
inline unsigned getCount(void)
{return (unsigned)(size / sizeof(T));};
};
END_NAMESPACE
#endif