Class mdbx::cursor_managed

ClassList > mdbx > cursor_managed

Managed cursor. More...

#include <mdbx.h++>

Inherits the following classes: mdbx::cursor

Public Types inherited from mdbx::cursor

Type	Name
enum	bunch_delete Modes for deleting bunches of neighboring items, see MDBX_bunch_action_t() . The EXCLUDING and INCLUDING suffixes mean correspondingly excluding and including deletion items in the current cursor position.
enum	move_operation Cursor positioning operations, mirrors MDBX_cursor_op .

Public Functions

Type	Name
void	close () Explicitly closes the cursor.
	cursor_managed (void * your_context=nullptr) Creates a new managed cursor with underlying object.
	cursor_managed (cursor_managed &&) = default Move constructor.
	cursor_managed (const cursor_managed &) = delete Copy construction is prohibited.
cursor_managed &	operator= (cursor_managed && other) noexcept Move assignment operator.
cursor_managed &	operator= (const cursor_managed &) = delete Copy assignment is prohibited.
MDBX_cursor *	withdraw_handle () noexcept Withdraws (takes over) the underlying C handle; this instance becomes empty and will not close the cursor.
	~cursor_managed () Destroys the managed cursor, closing the underlying object.

Public Functions inherited from mdbx::cursor

See mdbx::cursor

Type	Name
cursor_managed	clone (void * your_context=nullptr) const Creates a new managed cursor with the same position and context.
move_result	current (bool throw_notfound=true) const Read the current key/data item without moving.
constexpr	cursor () noexcept Constructs an empty (null) cursor.
	cursor (const cursor &) noexcept Copy constructor.
	cursor (cursor_managed &&) = delete
ptrdiff_t	distance_from (const cursor from, unsigned deepness=42) const Estimates the distance from the given cursor position to this one.
ptrdiff_t	distance_from_first (unsigned deepness=42) const Estimates the distance from the first item of the table to this cursor position.
ptrdiff_t	distance_to (const cursor to, unsigned deepness=42) const Estimates the distance from this cursor position to the given one.
ptrdiff_t	distance_to_end (unsigned deepness=42) const Estimates the distance from this cursor position to the end of the table.
bool	erase (CHARS key, BOOL whole_multivalue=true) Overloads for C strings, which otherwise bind to the `bool` parameters above.
bool	erase (const slice & key, const char(&) value) Removes the particular multi-value entry given by C string literals.
bool	erase (const char(&) key, const char(&) value) Removes the particular multi-value entry given by C string literals.
bool	fullscan (CALLABLE_PREDICATE predicate, bool backward=false) Scans the whole table calling the predicate until it returns `true` .
move_result	get_multiple_samelength (bool throw_notfound=false) Returns a batch of same-length multi-values at the current key.
const MDBX_cursor *	handle () noexcept const Returns the underlying C handle (read-only).
MDBX_cursor *	handle () noexcept Returns the underlying C handle.
void	insert (const pair & kv) Inserts a new key-value pair; fails if the key already exists.
bool	is_after_than (const cursor & other, bool ignore_nested=false) const Checks whether this cursor is after the given one.
bool	is_before_than (const cursor & other, bool ignore_nested=false) const Checks whether this cursor is before the given one.
bool	is_same_or_after_than (const cursor & other, bool ignore_nested=false) const Checks whether this cursor is at the same position or after the given one.
bool	is_same_or_before_than (const cursor & other, bool ignore_nested=false) const Checks whether this cursor is at the same position or before the given one.
bool	is_same_position (const cursor & other, bool ignore_nested=false) const Checks whether this cursor is at the same position as the given one.
move_result	move (move_operation operation, bool throw_notfound) Performs the given positioning operation.
move_result	move (move_operation operation, const slice & key, bool throw_notfound) Performs the given positioning operation at the specified key.
move_result	move (move_operation operation, const slice & key, const slice & value, bool throw_notfound) Performs the given positioning operation at the specified key-value pair.
move_result	move (move_operation operation, const slice & key, const slice & value) = delete Deleted: `throw_notfound` must be specified explicitly to avoid accidental boolean conversions.
bool	move (move_operation operation, SLICE & key, SLICE & value, bool throw_notfound) Performs the given positioning operation updating the key and value slices.
move_result	next_multiple_samelength (bool throw_notfound=false) Moves to the next key and returns its batch of same-length multi-values.
constexpr	operator MDBX_cursor * () noexcept Returns the underlying C handle.
constexpr	operator const MDBX_cursor * () noexcept const Returns the underlying C handle (read-only).
	map_handle () const Converts the cursor to its table handle.
	txn () const Converts the cursor to its transaction.
cursor &	operator= (const cursor &) noexcept Copy assignment operator.
cursor &	operator= (cursor_managed &&) = delete
move_result	previous_multiple_samelength (bool throw_notfound=false) Moves to the previous key and returns its batch of same-length multi-values.
void	put (const pair & kv, put_mode mode) Stores a key-value pair in the given mode.
size_t	put_multiple_samelength (const slice & key, const VALUE * values_array, size_t values_count, put_mode mode, bool allow_partial=false) Stores a bunch of same-length multi-values for the given key.
void	put_multiple_samelength (const slice & key, const ::std::vector< VALUE > & vector, put_mode mode) Stores a bunch of same-length multi-values for the given key.
slice	reserve_current (size_t value_length) Reserves and returns the space for storing a value associated with a key at the current cursor position.
slice	reverse_current (size_t value_length) Deprecated misspelling of reserve_current() .
bool	scan_until (CALLABLE_PREDICATE predicate, move_operation start=first, move_operation turn=next) Scans items calling the predicate until it returns `true` .
bool	scan_until_from (CALLABLE_PREDICATE predicate, slice & from, move_operation start=key_greater_or_equal, move_operation turn=next) Scans items starting from the given key, calling the predicate until it returns `true` .
bool	scan_until_from (CALLABLE_PREDICATE predicate, pair & from, move_operation start=pair_greater_or_equal, move_operation turn=next) Scans items starting from the given key-value pair, calling the predicate until it returns `true` .
move_result	seek_multiple_samelength (const slice & key, bool throw_notfound=true) Seeks and returns a batch of same-length multi-values of the given key.
move_result	to_current_first_multi (bool throw_notfound=true) Position the cursor at the first multi-value of the current key.
move_result	to_current_last_multi (bool throw_notfound=true) Position the cursor at the last multi-value of the current key.
move_result	to_current_next_multi (bool throw_notfound=true) Position the cursor at the next multi-value of the current key.
move_result	to_current_prev_multi (bool throw_notfound=true) Position the cursor at the previous multi-value of the current key.
move_result	to_exact_key_value_equal (const slice & key, const slice & value, bool throw_notfound=true) Position the cursor at the exact key and the multi-value equal to the given one.
move_result	to_exact_key_value_greater_or_equal (const slice & key, const slice & value, bool throw_notfound=true) Position the cursor at the exact key and the multi-value greater than or equal to the given one.
move_result	to_exact_key_value_greater_than (const slice & key, const slice & value, bool throw_notfound=true) Position the cursor at the exact key and the multi-value greater than the given one.
move_result	to_exact_key_value_lesser_or_equal (const slice & key, const slice & value, bool throw_notfound=true) Position the cursor at the exact key and the multi-value lesser than or equal to the given one.
move_result	to_exact_key_value_lesser_than (const slice & key, const slice & value, bool throw_notfound=true) Position the cursor at the exact key and the multi-value lesser than the given one.
move_result	to_first (bool throw_notfound=true) Position the cursor at the first key/data item.
move_result	to_key_equal (const slice & key, bool throw_notfound=true) Position the cursor at the key equal to the given one.
move_result	to_key_exact (const slice & key, bool throw_notfound=true) Position the cursor at the key exactly matching the given one.
move_result	to_key_greater_or_equal (const slice & key, bool throw_notfound=true) Position the cursor at the key greater than or equal to the given one.
move_result	to_key_greater_than (const slice & key, bool throw_notfound=true) Position the cursor at the key greater than the given one.
move_result	to_key_lesser_or_equal (const slice & key, bool throw_notfound=true) Position the cursor at the key lesser than or equal to the given one.
move_result	to_key_lesser_than (const slice & key, bool throw_notfound=true) Position the cursor at the key lesser than the given one.
move_result	to_last (bool throw_notfound=true) Position the cursor at the last key/data item.
move_result	to_next (bool throw_notfound=true) Position the cursor at the next key/data item.
move_result	to_next_first_multi (bool throw_notfound=true) Position the cursor at the first multi-value of the next key.
move_result	to_pair_equal (const slice & key, const slice & value, bool throw_notfound=true) Position the cursor at the key-value pair equal to the given one.
move_result	to_pair_exact (const slice & key, const slice & value, bool throw_notfound=true) Position the cursor at the key-value pair exactly matching the given one.
move_result	to_pair_greater_or_equal (const slice & key, const slice & value, bool throw_notfound=true) Position the cursor at the key-value pair greater than or equal to the given one.
move_result	to_pair_greater_than (const slice & key, const slice & value, bool throw_notfound=true) Position the cursor at the key-value pair greater than the given one.
move_result	to_pair_lesser_or_equal (const slice & key, const slice & value, bool throw_notfound=true) Position the cursor at the key-value pair lesser than or equal to the given one.
move_result	to_pair_lesser_than (const slice & key, const slice & value, bool throw_notfound=true) Position the cursor at the key-value pair lesser than the given one.
move_result	to_previous (bool throw_notfound=true) Position the cursor at the previous key/data item.
move_result	to_previous_last_multi (bool throw_notfound=true) Position the cursor at the last multi-value of the previous key.
value_result	try_insert (const pair & kv) Tries to insert a new key-value pair without throwing on a duplicate.
void	update_current (const slice & value) Updates value associated with a key at the current cursor position.
void	upsert (const pair & kv) Inserts or updates the value for the given key.

Protected Attributes inherited from mdbx::cursor

See mdbx::cursor

Type	Name
MDBX_cursor *	handle_ = `{nullptr}` The underlying C cursor handle, null for an empty instance.

Detailed Description

As other managed classes, cursor_managed destroys the represented underlying object from the own class destructor, but disallows copying and assignment for instances.

See also: mdbx_cursor_create()

See also: mdbx_cursor_bind()

See also: mdbx_cursor_close()

Public Functions Documentation

function close

Explicitly closes the cursor.

void mdbx::cursor_managed::close ()

function cursor_managed [2/4]

Creates a new managed cursor with underlying object.

inline mdbx::cursor_managed::cursor_managed (
    void * your_context=nullptr
)

Parameters:

your_context An application context to be associated with the cursor.

Exception:

mdbx::error on failure to allocate the underlying object.

function cursor_managed [3/4]

Move constructor.

mdbx::cursor_managed::cursor_managed (
    cursor_managed &&
) = default

function cursor_managed [4/4]

Copy construction is prohibited.

mdbx::cursor_managed::cursor_managed (
    const cursor_managed &
) = delete

function operator=

Move assignment operator.

cursor_managed & mdbx::cursor_managed::operator= (
    cursor_managed && other
) noexcept

Parameters:

other The source managed cursor to be moved from.

Returns:

A reference to this instance.

function operator=

Copy assignment is prohibited.

cursor_managed & mdbx::cursor_managed::operator= (
    const cursor_managed &
) = delete

function withdraw_handle

Withdraws (takes over) the underlying C handle; this instance becomes empty and will not close the cursor.

inline MDBX_cursor * mdbx::cursor_managed::withdraw_handle () noexcept

Returns:

The pointer to the underlying MDBX_cursor object.

function ~cursor_managed

Destroys the managed cursor, closing the underlying object.

mdbx::cursor_managed::~cursor_managed ()

The documentation for this class was generated from the following file mdbx.h++