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// file : odb/vector-impl.hxx
// copyright : Copyright (c) 2009-2013 Code Synthesis Tools CC
// license : GNU GPL v2; see accompanying LICENSE file
#ifndef ODB_VECTOR_IMPL_HXX
#define ODB_VECTOR_IMPL_HXX
#include <odb/pre.hxx>
#include <odb/details/config.hxx> // ODB_CXX11
#include <new>
#include <cstddef> // std::size_t
#include <odb/transaction.hxx>
#include <odb/details/export.hxx>
namespace odb
{
// Change tracking vector implementation details.
//
class LIBODB_EXPORT vector_impl
{
public:
enum element_state_type
{
state_unchanged,
state_inserted,
state_updated,
state_erased
};
enum container_state_type
{
state_tracking,
state_not_tracking,
state_changed // Container has changed but individual changes
// were not tracked.
};
vector_impl ();
~vector_impl ();
// The copy constructor will copy the state. The idea is that the
// copy keeps tracking changes, just like the original.
//
vector_impl (const vector_impl&);
#ifdef ODB_CXX11
vector_impl (vector_impl&&);
#endif
void
swap (vector_impl& x);
// Allocate enough memory to store the specified number of
// elements.
//
void
reserve (std::size_t);
// Reduce capacity to size.
//
void
shrink_to_fit ();
// Capacity (each entry takes 2 bits).
//
std::size_t
capacity () const;
// (Re)start tracking changes for a vector with n elements.
//
void
start (std::size_t);
// Stop tracking changes.
//
void
stop ();
// Mark the container as changed without tracking the changes.
// This state is useful as a fallback mechnism for situations
// where the change information has been discarded (e.g., after
// its state has been updated in the database) but the container
// should remain changed (e.g., after the transaction is rolled
// back).
//
void
change ();
// Get the state of the container.
//
container_state_type
state () const;
// Shortcut for state() == state_tracking.
//
bool
tracking () const;
// Note that the returned size can be greater than the actual,
// parallel vector size. In this case the difference is the
// erased elements at the back.
//
std::size_t
size () const;
// Get the change state of the specified element.
//
element_state_type
state (std::size_t) const;
// Change notifications.
//
void
push_back (std::size_t n = 1);
void
pop_back (std::size_t n = 1);
void
insert (std::size_t, std::size_t n = 1);
void
erase (std::size_t, std::size_t n = 1);
void
modify (std::size_t, std::size_t n = 1);
void
clear ();
void
assign (std::size_t n);
void
resize (std::size_t n);
private:
// Assignment does not make sense (it is changing of the content).
//
vector_impl& operator= (const vector_impl&);
private:
void
realloc (std::size_t);
void
set (std::size_t, element_state_type);
static const unsigned char mask_[4];
static const unsigned char shift_[4];
container_state_type state_;
// Size, tail, and capacity are in 2-bit blocks. Size is the number
// of elements we have in data. Tail is the position of the first
// erased element at the back. If there are no erased elements, then
// tail is equal size. Capacity is the number of elements we can
// store in data.
//
std::size_t size_;
std::size_t tail_;
std::size_t capacity_;
unsigned char* data_;
};
// Base class that provides a change tracking interface and
// handles the rollback callback. The only function that's
// missing is _start() which needs to know the number of
// elements currently in the vector.
//
class LIBODB_EXPORT vector_base
{
public:
void
_stop () const {impl_.stop ();}
bool
_tracking () const {return impl_.tracking ();}
void
_arm (transaction& t) const;
vector_impl&
_impl () const {return impl_;}
private:
// Assignment is changing of the content.
//
vector_base& operator= (const vector_base&);
protected:
vector_base (): tran_ (0) {}
~vector_base () {if (tran_ != 0) tran_->callback_unregister (this);}
vector_base (const vector_base&);
#ifdef ODB_CXX11
vector_base (vector_base&&);
#endif
void
swap (vector_base&);
static void
rollback (unsigned short, void* key, unsigned long long);
private:
void
swap_tran (vector_base&);
protected:
mutable vector_impl impl_;
mutable transaction* tran_;
};
}
#include <odb/vector-impl.ixx>
#include <odb/post.hxx>
#endif // ODB_VECTOR_IMPL_HXX
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