#include <stdio.h>
#include <string.h>
#include "CLG_log.h"
#include "BLI_listbase.h"
#include "BLI_string.h"
#include "BLI_sys_types.h"
#include "BLI_utildefines.h"
#include "BLT_translation.h"
#include "DNA_listBase.h"
#include "DNA_windowmanager_types.h"
#include "BKE_context.h"
#include "BKE_global.h"
#include "BKE_lib_override.h"
#include "BKE_main.h"
#include "BKE_undo_system.h"
#include "MEM_guardedalloc.h"

Macros
#define	undo_stack _wm_undo_stack_disallow /* pass in as a variable always. */

#define	WITH_GLOBAL_UNDO_KEEP_ONE

#define	WITH_GLOBAL_UNDO_ENSURE_UPDATED

#define	WITH_GLOBAL_UNDO_CORRECT_ORDER

Functions
Internal Callback Wrappers
UndoRefID is simply a way to avoid in-lining name copy and lookups, since it's easy to forget a single case when done inline (crashing in some cases).
static void	undosys_id_ref_store (void UNUSED(user_data), UndoRefID id_ref)

static void	undosys_id_ref_resolve (void user_data, UndoRefID id_ref)

static bool	undosys_step_encode (bContext C, Main bmain, UndoStack ustack, UndoStep us)

static void	undosys_step_decode (bContext C, Main bmain, UndoStack ustack, UndoStep us, const eUndoStepDir dir, bool is_final)

static void	undosys_step_free_and_unlink (UndoStack ustack, UndoStep us)

Undo Stack
static void	undosys_stack_validate (UndoStack *ustack, bool expect_non_empty)

UndoStack *	BKE_undosys_stack_create (void)

void	BKE_undosys_stack_destroy (UndoStack *ustack)

void	BKE_undosys_stack_clear (UndoStack *ustack)

void	BKE_undosys_stack_clear_active (UndoStack *ustack)

static void	undosys_stack_clear_all_last (UndoStack ustack, UndoStep us)

static void	undosys_stack_clear_all_first (UndoStack ustack, UndoStep us, UndoStep *us_exclude)

static bool	undosys_stack_push_main (UndoStack ustack, const char name, struct Main *bmain)

void	BKE_undosys_stack_init_from_main (UndoStack ustack, struct Main bmain)

void	BKE_undosys_stack_init_from_context (UndoStack ustack, bContext C)

bool	BKE_undosys_stack_has_undo (const UndoStack ustack, const char name)

UndoStep *	BKE_undosys_stack_active_with_type (UndoStack ustack, const UndoType ut)

UndoStep *	BKE_undosys_stack_init_or_active_with_type (UndoStack ustack, const UndoType ut)

void	BKE_undosys_stack_limit_steps_and_memory (UndoStack *ustack, int steps, size_t memory_limit)

Undo Step
UndoStep *	BKE_undosys_step_push_init_with_type (UndoStack ustack, bContext C, const char name, const UndoType ut)

UndoStep *	BKE_undosys_step_push_init (UndoStack ustack, bContext C, const char *name)

eUndoPushReturn	BKE_undosys_step_push_with_type (UndoStack ustack, bContext C, const char name, const UndoType ut)

eUndoPushReturn	BKE_undosys_step_push (UndoStack ustack, bContext C, const char *name)

UndoStep *	BKE_undosys_step_same_type_next (UndoStep *us)

UndoStep *	BKE_undosys_step_same_type_prev (UndoStep *us)

UndoStep *	BKE_undosys_step_find_by_name_with_type (UndoStack ustack, const char name, const UndoType *ut)

UndoStep *	BKE_undosys_step_find_by_name (UndoStack ustack, const char name)

UndoStep *	BKE_undosys_step_find_by_type (UndoStack ustack, const UndoType ut)

eUndoStepDir	BKE_undosys_step_calc_direction (const UndoStack ustack, const UndoStep us_target, const UndoStep *us_reference)

static UndoStep *	undosys_step_iter_first (UndoStep *us_reference, const eUndoStepDir undo_dir)

bool	BKE_undosys_step_load_data_ex (UndoStack ustack, bContext C, UndoStep us_target, UndoStep us_reference, const bool use_skip)

bool	BKE_undosys_step_load_data (UndoStack ustack, bContext C, UndoStep *us_target)

void	BKE_undosys_step_load_from_index (UndoStack ustack, bContext C, const int index)

bool	BKE_undosys_step_undo_with_data_ex (UndoStack ustack, bContext C, UndoStep *us_target, bool use_skip)

bool	BKE_undosys_step_undo_with_data (UndoStack ustack, bContext C, UndoStep *us_target)

bool	BKE_undosys_step_undo (UndoStack ustack, bContext C)

bool	BKE_undosys_step_redo_with_data_ex (UndoStack ustack, bContext C, UndoStep *us_target, bool use_skip)

bool	BKE_undosys_step_redo_with_data (UndoStack ustack, bContext C, UndoStep *us_target)

bool	BKE_undosys_step_redo (UndoStack ustack, bContext C)

UndoType *	BKE_undosys_type_append (void(undosys_fn)(UndoType ))

void	BKE_undosys_type_free_all (void)

Undo Stack Grouping
This enables skip while group-level is set. In general it's not allowed that UndoStack.step_active have 'skip' enabled. This rule is relaxed for grouping, however it's important each call to BKE_undosys_stack_group_begin has a matching BKE_undosys_stack_group_end. Levels are used so nesting is supported, where the last call to BKE_undosys_stack_group_end will set the active undo step that should not be skipped. Correct begin/end is checked by an assert since any errors here will cause undo to consider all steps part of one large group. Calls to begin/end with no undo steps being pushed is supported and does nothing.
void	BKE_undosys_stack_group_begin (UndoStack *ustack)

void	BKE_undosys_stack_group_end (UndoStack *ustack)

ID Reference Utilities
Unfortunately we need this for a handful of places.
static void	UNUSED_FUNCTION (BKE_undosys_foreach_ID_ref(UndoStack ustack, UndoTypeForEachIDRefFn foreach_ID_ref_fn, void user_data))

Debug Helpers
void	BKE_undosys_print (UndoStack *ustack)

Variables
static CLG_LogRef	LOG = {"bke.undosys"}

Internal Nested Undo Checks
Make sure we're not running undo operations from 'step_encode', 'step_decode' callbacks. bugs caused by this situation aren't that hard to spot but aren't always so obvious. Best we have a check which shows the problem immediately.
#define	WITH_NESTED_UNDO_CHECK

#define	UNDO_NESTED_ASSERT(state) BLI_assert(g_undo_callback_running == state)

#define	UNDO_NESTED_CHECK_BEGIN

#define	UNDO_NESTED_CHECK_END

static bool	g_undo_callback_running = false

Undo Types
const UndoType *	BKE_UNDOSYS_TYPE_IMAGE = NULL

const UndoType *	BKE_UNDOSYS_TYPE_MEMFILE = NULL

const UndoType *	BKE_UNDOSYS_TYPE_PAINTCURVE = NULL

const UndoType *	BKE_UNDOSYS_TYPE_PARTICLE = NULL

const UndoType *	BKE_UNDOSYS_TYPE_SCULPT = NULL

const UndoType *	BKE_UNDOSYS_TYPE_TEXT = NULL

static ListBase	g_undo_types = {NULL, NULL}

static const UndoType *	BKE_undosys_type_from_context (bContext *C)

Detailed Description

Used by ED_undo.h, internal implementation.

Definition in file undo_system.c.

Macro Definition Documentation

◆ UNDO_NESTED_ASSERT

#define UNDO_NESTED_ASSERT ( state ) BLI_assert(g_undo_callback_running == state)

Definition at line 87 of file undo_system.c.

◆ UNDO_NESTED_CHECK_BEGIN

#define UNDO_NESTED_CHECK_BEGIN

Value:

    { \
      UNDO_NESTED_ASSERT(false); \
      g_undo_callback_running = true; \
    } \
    ((void)0)

Definition at line 88 of file undo_system.c.

◆ UNDO_NESTED_CHECK_END

#define UNDO_NESTED_CHECK_END

Value:

    { \
      UNDO_NESTED_ASSERT(true); \
      g_undo_callback_running = false; \
    } \
    ((void)0)

Definition at line 94 of file undo_system.c.

◆ undo_stack

#define undo_stack _wm_undo_stack_disallow /* pass in as a variable always. */

Definition at line 32 of file undo_system.c.

◆ WITH_GLOBAL_UNDO_CORRECT_ORDER

#define WITH_GLOBAL_UNDO_CORRECT_ORDER

Make sure we don't apply edits on top of a newer memfile state, see: T56163.

Note: Keep an eye on this, could solve differently.

Definition at line 44 of file undo_system.c.

◆ WITH_GLOBAL_UNDO_ENSURE_UPDATED

#define WITH_GLOBAL_UNDO_ENSURE_UPDATED

Make sure all ID's created at the point we add an undo step that uses ID's.

Definition at line 38 of file undo_system.c.

◆ WITH_GLOBAL_UNDO_KEEP_ONE

#define WITH_GLOBAL_UNDO_KEEP_ONE

Odd requirement of Blender that we always keep a memfile undo in the stack.

Definition at line 35 of file undo_system.c.

◆ WITH_NESTED_UNDO_CHECK

#define WITH_NESTED_UNDO_CHECK

Definition at line 83 of file undo_system.c.

Function Documentation

◆ BKE_undosys_print()

void BKE_undosys_print ( UndoStack * ustack )

Definition at line 963 of file undo_system.c.

References BLI_listbase_count(), LISTBASE_FOREACH, UndoStack::step_active, UndoStack::step_active_memfile, and UndoStack::steps.

Referenced by ED_undo_push(), and ed_undo_step_post().

◆ BKE_undosys_stack_active_with_type()

UndoStep* BKE_undosys_stack_active_with_type	(	UndoStack *	ustack,
		const UndoType *	ut
	)

Definition at line 364 of file undo_system.c.

References UndoStep::prev, UndoStack::step_active, and UndoStep::type.

Referenced by BKE_undosys_stack_init_or_active_with_type(), and ED_undosys_stack_memfile_get_active().

◆ BKE_undosys_stack_clear()

void BKE_undosys_stack_clear ( UndoStack * ustack )

Definition at line 262 of file undo_system.c.

References BLI_listbase_clear(), BLI_listbase_count(), CLOG_INFO, ListBase::last, LOG, NULL, UndoStack::step_active, UndoStack::steps, UNDO_NESTED_ASSERT, and undosys_step_free_and_unlink().

Referenced by BKE_undosys_stack_destroy(), and wm_file_read_post().

◆ BKE_undosys_stack_clear_active()

void BKE_undosys_stack_clear_active ( UndoStack * ustack )

Definition at line 274 of file undo_system.c.

References ListBase::last, NULL, UndoStep::prev, UndoStack::step_active, UndoStack::steps, undosys_stack_validate(), and undosys_step_free_and_unlink().

Referenced by ED_undo_grouped_push().

◆ BKE_undosys_stack_create()

UndoStack* BKE_undosys_stack_create ( void )

Definition at line 250 of file undo_system.c.

References MEM_callocN.

Referenced by ed_undo_push_exec(), and wm_file_read_post().

◆ BKE_undosys_stack_destroy()

void BKE_undosys_stack_destroy ( UndoStack * ustack )

Definition at line 256 of file undo_system.c.

References BKE_undosys_stack_clear(), and MEM_freeN.

Referenced by ED_editors_exit(), and wm_close_and_free().

◆ BKE_undosys_stack_group_begin()

void BKE_undosys_stack_group_begin ( UndoStack * ustack )

Definition at line 919 of file undo_system.c.

References BLI_assert, and UndoStack::group_level.

Referenced by ED_undo_group_begin().

◆ BKE_undosys_stack_group_end()

void BKE_undosys_stack_group_end ( UndoStack * ustack )

Definition at line 925 of file undo_system.c.

References BLI_assert, UndoStack::group_level, LIKELY, NULL, UndoStep::skip, and UndoStack::step_active.

Referenced by ED_undo_group_end().

◆ BKE_undosys_stack_has_undo()

bool BKE_undosys_stack_has_undo	(	const UndoStack *	ustack,
		const char *	name
	)

Definition at line 354 of file undo_system.c.

References BLI_listbase_is_empty(), BLI_rfindstring(), UndoStep::prev, and UndoStack::steps.

Referenced by ED_undo_is_valid().

◆ BKE_undosys_stack_init_from_context()

void BKE_undosys_stack_init_from_context	(	UndoStack *	ustack,
		bContext *	C
	)

Definition at line 346 of file undo_system.c.

References BKE_undosys_step_push_with_type(), BKE_undosys_type_from_context(), BKE_UNDOSYS_TYPE_MEMFILE, C, ELEM, IFACE_, and NULL.

Referenced by wm_file_read_post().

◆ BKE_undosys_stack_init_from_main()

void BKE_undosys_stack_init_from_main	(	UndoStack *	ustack,
		struct Main *	bmain
	)

Definition at line 340 of file undo_system.c.

References IFACE_, UNDO_NESTED_ASSERT, and undosys_stack_push_main().

Referenced by wm_file_read_post().

◆ BKE_undosys_stack_init_or_active_with_type()

UndoStep* BKE_undosys_stack_init_or_active_with_type	(	UndoStack *	ustack,
		const UndoType *	ut
	)

Definition at line 373 of file undo_system.c.

References BKE_undosys_stack_active_with_type(), CLOG_INFO, LOG, UndoType::name, UndoStack::step_init, UndoStep::type, and UNDO_NESTED_ASSERT.

Referenced by ED_image_paint_tile_map_get(), sculpt_undo_get_nodes(), and SCULPT_undo_push_end_ex().

◆ BKE_undosys_stack_limit_steps_and_memory()

void BKE_undosys_stack_limit_steps_and_memory	(	UndoStack *	ustack,
		int	steps,
		size_t	memory_limit
	)

Parameters

steps	Limit the number of undo steps.
memory_limit	Limit the amount of memory used by the undo stack.

Definition at line 383 of file undo_system.c.

References BKE_UNDOSYS_TYPE_MEMFILE, CLOG_INFO, UndoStep::data_size, ListBase::last, LOG, memory_limit, NULL, UndoStep::prev, UndoStep::skip, steps, UndoStack::steps, UndoStep::type, UNDO_NESTED_ASSERT, and undosys_stack_clear_all_first().

Referenced by ED_undo_push().

◆ BKE_undosys_step_calc_direction()

eUndoStepDir BKE_undosys_step_calc_direction	(	const UndoStack *	ustack,
		const UndoStep *	us_target,
		const UndoStep *	us_reference
	)

Return direction of the undo/redo from us_reference (or ustack->step_active if NULL), and us_target.

Note: If us_reference and us_target are the same, we consider this is an undo.

Returns: -1 for undo, 1 for redo, 0 in case of error.

Definition at line 659 of file undo_system.c.

References BLI_assert, BLI_assert_msg, ELEM, UndoStep::next, NULL, UndoStep::prev, UndoStack::step_active, STEP_INVALID, STEP_REDO, and STEP_UNDO.

Referenced by BKE_undosys_step_load_data_ex(), BKE_undosys_step_redo_with_data_ex(), BKE_undosys_step_undo_with_data_ex(), and ed_undo_step_by_name().

◆ BKE_undosys_step_find_by_name()

UndoStep* BKE_undosys_step_find_by_name	(	UndoStack *	ustack,
		const char *	name
	)

Definition at line 644 of file undo_system.c.

References BLI_rfindstring(), and UndoStack::steps.

Referenced by ed_undo_step_by_name().

◆ BKE_undosys_step_find_by_name_with_type()

UndoStep* BKE_undosys_step_find_by_name_with_type	(	UndoStack *	ustack,
		const char *	name,
		const UndoType *	ut
	)

Definition at line 630 of file undo_system.c.

References ListBase::last, NULL, UndoStack::steps, and STREQ.

◆ BKE_undosys_step_find_by_type()

UndoStep* BKE_undosys_step_find_by_type	(	UndoStack *	ustack,
		const UndoType *	ut
	)

Definition at line 649 of file undo_system.c.

References ListBase::last, NULL, and UndoStack::steps.

Referenced by memfile_undosys_step_encode().

◆ BKE_undosys_step_load_data()

bool BKE_undosys_step_load_data	(	UndoStack *	ustack,
		struct bContext *	C,
		UndoStep *	us_target
	)

Undo/Redo until the given us_target step becomes the active (currently loaded) one.

Definition at line 806 of file undo_system.c.

References BKE_undosys_step_load_data_ex(), C, and NULL.

Referenced by BKE_undosys_step_load_from_index().

◆ BKE_undosys_step_load_data_ex()

bool BKE_undosys_step_load_data_ex	(	UndoStack *	ustack,
		struct bContext *	C,
		UndoStep *	us_target,
		UndoStep *	us_reference,
		bool	use_skip
	)

Undo/Redo until the given us_target step becomes the active (currently loaded) one.

Note: Unless us_target is a 'skipped' one and use_skip is true, us_target will become the active step.; In case use_skip is true, the final target will always be beyond the given one (if the given one has to be skipped).

Parameters

us_reference If NULL, will be set to current active step in the undo stack. Otherwise, it is assumed to match the current state, and will be used as basis for the undo/redo process (i.e. all steps in-between us_reference and us_target will be processed).

Definition at line 718 of file undo_system.c.

References BKE_undosys_step_calc_direction(), BLI_assert, C, CLOG_ERROR, CLOG_INFO, G_MAIN, LOG, UndoStep::name, UndoType::name, UndoStep::next, NULL, UndoStep::prev, UndoStep::skip, UndoStack::step_active, STEP_INVALID, CLG_LogRef::type, UndoStep::type, UNDO_NESTED_ASSERT, undosys_stack_validate(), undosys_step_decode(), and undosys_step_iter_first().

Referenced by BKE_undosys_step_load_data(), BKE_undosys_step_redo_with_data_ex(), BKE_undosys_step_undo_with_data_ex(), and ed_undo_step_by_name().

◆ BKE_undosys_step_load_from_index()

void BKE_undosys_step_load_from_index	(	UndoStack *	ustack,
		struct bContext *	C,
		int	index
	)

Undo/Redo until the step matching given index in the undo stack becomes the active (currently loaded) one.

Definition at line 812 of file undo_system.c.

References BKE_undosys_step_load_data(), BLI_assert, BLI_findlink(), C, UndoStep::skip, UndoStack::step_active, and UndoStack::steps.

Referenced by ed_undo_step_by_index().

◆ BKE_undosys_step_push()

eUndoPushReturn BKE_undosys_step_push	(	UndoStack *	ustack,
		bContext *	C,
		const char *	name
	)

Definition at line 593 of file undo_system.c.

References BKE_undosys_step_push_with_type(), BKE_undosys_type_from_context(), C, NULL, UndoStack::step_init, UndoStep::type, and UNDO_NESTED_ASSERT.

Referenced by ED_image_undo_push_end(), ED_paintcurve_undo_push_end(), ED_undo_push(), and SCULPT_undo_push_end_ex().

◆ BKE_undosys_step_push_init()

UndoStep* BKE_undosys_step_push_init	(	UndoStack *	ustack,
		bContext *	C,
		const char *	name
	)

Definition at line 479 of file undo_system.c.

References BKE_undosys_step_push_init_with_type(), BKE_undosys_type_from_context(), BLI_assert, C, NULL, UndoStack::step_init, and UNDO_NESTED_ASSERT.

◆ BKE_undosys_step_push_init_with_type()

UndoStep* BKE_undosys_step_push_init_with_type	(	UndoStack *	ustack,
		struct bContext *	C,
		const char *	name,
		const UndoType *	ut
	)

Only some UndoType's require init.

Definition at line 449 of file undo_system.c.

References BLI_assert, BLI_strncpy(), C, CLOG_INFO, LOG, MEM_callocN, UndoStep::name, UndoType::name, UndoStep::next, NULL, UndoStack::step_active, UndoType::step_encode_init, UndoStack::step_init, UndoType::step_size, UndoStep::type, UNDO_NESTED_ASSERT, undosys_stack_clear_all_last(), and undosys_stack_validate().

Referenced by BKE_undosys_step_push_init(), ED_paintcurve_undo_push_begin(), ED_text_undo_push_init(), image_undo_push_begin(), and SCULPT_undo_push_begin().

◆ BKE_undosys_step_push_with_type()

eUndoPushReturn BKE_undosys_step_push_with_type	(	UndoStack *	ustack,
		struct bContext *	C,
		const char *	name,
		const UndoType *	ut
	)

Parameters

C	Can be NULL from some callers if their encoding function doesn't need it

Definition at line 491 of file undo_system.c.

References BKE_lib_override_library_main_operations_create(), BLI_addtail(), BLI_assert, BLI_findindex(), BLI_strncpy(), C, CLOG_INFO, UndoType::flags, G_MAIN, UndoStack::group_level, ListBase::last, LOG, MEM_callocN, MEM_freeN, UndoStep::name, UndoType::name, NULL, UndoStep::skip, UndoStack::step_active, UndoStack::step_active_memfile, UndoType::step_foreach_ID_ref, UndoStack::step_init, UndoType::step_size, UndoStack::steps, STREQ, UndoStep::type, UNDO_NESTED_ASSERT, UNDO_PUSH_RET_FAILURE, UNDO_PUSH_RET_OVERRIDE_CHANGED, UNDO_PUSH_RET_SUCCESS, undosys_stack_push_main(), undosys_stack_validate(), undosys_step_encode(), undosys_step_free_and_unlink(), UNDOTYPE_FLAG_NEED_CONTEXT_FOR_ENCODE, UndoStep::use_memfile_step, and UndoStep::use_old_bmain_data.

Referenced by BKE_undosys_stack_init_from_context(), BKE_undosys_step_push(), and undosys_stack_push_main().

◆ BKE_undosys_step_redo()

bool BKE_undosys_step_redo	(	UndoStack *	ustack,
		struct bContext *	C
	)

Redo one step from current active one.

Definition at line 869 of file undo_system.c.

References BKE_undosys_step_redo_with_data(), C, UndoStep::next, NULL, and UndoStack::step_active.

Referenced by ed_undo_step_direction().

◆ BKE_undosys_step_redo_with_data()

bool BKE_undosys_step_redo_with_data	(	UndoStack *	ustack,
		struct bContext *	C,
		UndoStep *	us_target
	)

Redo until us_target step becomes the active (currently loaded) one.

Note: See BKE_undosys_step_redo_with_data_ex for details.

Definition at line 864 of file undo_system.c.

References BKE_undosys_step_redo_with_data_ex(), and C.

Referenced by BKE_undosys_step_redo().

◆ BKE_undosys_step_redo_with_data_ex()

bool BKE_undosys_step_redo_with_data_ex	(	UndoStack *	ustack,
		struct bContext *	C,
		UndoStep *	us,
		bool	use_skip
	)

Redo until us_target step becomes the active (currently loaded) one.

Warning: This function assumes that the given target step is after current active one.

Note: Unless us_target is a 'skipped' one and use_skip is true, us_target will become the active step.; In case use_skip is true, the final target will always be after the given one (if the given one has to be skipped).

Definition at line 850 of file undo_system.c.

References BKE_undosys_step_calc_direction(), BKE_undosys_step_load_data_ex(), BLI_assert, C, NULL, UndoStep::prev, and UndoStack::step_active.

Referenced by BKE_undosys_step_redo_with_data().

◆ BKE_undosys_step_same_type_next()

UndoStep* BKE_undosys_step_same_type_next ( UndoStep * us )

Useful when we want to diff against previous undo data but can't be sure the types match.

Definition at line 604 of file undo_system.c.

References UndoStep::next, and UndoStep::type.

Referenced by memfile_undosys_step_free().

◆ BKE_undosys_step_same_type_prev()

UndoStep* BKE_undosys_step_same_type_prev ( UndoStep * us )

Useful when we want to diff against previous undo data but can't be sure the types match.

Definition at line 617 of file undo_system.c.

References UndoStep::prev, and UndoStep::type.

◆ BKE_undosys_step_undo()

bool BKE_undosys_step_undo	(	UndoStack *	ustack,
		struct bContext *	C
	)

Undo one step from current active (currently loaded) one.

Definition at line 842 of file undo_system.c.

References BKE_undosys_step_undo_with_data(), C, NULL, UndoStep::prev, and UndoStack::step_active.

Referenced by ed_undo_step_direction().

◆ BKE_undosys_step_undo_with_data()

bool BKE_undosys_step_undo_with_data	(	UndoStack *	ustack,
		struct bContext *	C,
		UndoStep *	us_target
	)

Undo until us_target step becomes the active (currently loaded) one.

Note: See BKE_undosys_step_undo_with_data_ex for details.

Definition at line 837 of file undo_system.c.

References BKE_undosys_step_undo_with_data_ex(), and C.

Referenced by BKE_undosys_step_undo().

◆ BKE_undosys_step_undo_with_data_ex()

bool BKE_undosys_step_undo_with_data_ex	(	UndoStack *	ustack,
		struct bContext *	C,
		UndoStep *	us,
		bool	use_skip
	)

Undo until us_target step becomes the active (currently loaded) one.

Warning: This function assumes that the given target step is before current active one.

Note: Unless us_target is a 'skipped' one and use_skip is true, us_target will become the active step.; In case use_skip is true, the final target will always be before the given one (if the given one has to be skipped).

Definition at line 822 of file undo_system.c.

References BKE_undosys_step_calc_direction(), BKE_undosys_step_load_data_ex(), BLI_assert, C, NULL, and UndoStack::step_active.

Referenced by BKE_undosys_step_undo_with_data().