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/// @file
#ifndef U3_EVENTS_H
#define U3_EVENTS_H
#include "c3/c3.h"
#include "allocate.h"
#include "version.h"
/** Data structures.
**/
/* u3e_line: control line.
*/
typedef struct _u3e_line {
c3_w pag_w;
c3_w mug_w;
} u3e_line;
/* u3e_control: memory change, control file.
*/
typedef struct _u3e_control {
u3e_version ver_w; // version number
c3_w nor_w; // new page count north
c3_w sou_w; // new page count south
c3_w pgs_w; // number of changed pages
u3e_line mem_u[]; // per page
} u3e_control;
/* u3_cs_patch: memory change, top level.
*/
typedef struct _u3_cs_patch {
c3_i ctl_i;
c3_i mem_i;
u3e_control* con_u;
} u3_ce_patch;
/* u3e_image: memory segment, open file.
*/
typedef struct _u3e_image {
c3_c* nam_c; // segment name
c3_i fid_i; // open file, or 0
c3_w pgs_w; // length in pages
} u3e_image;
/* u3e_pool: entire memory system.
*/
typedef struct _u3e_pool {
c3_c* dir_c; // path to
c3_i eph_i; // ephemeral file descriptor
c3_w dit_w[u3a_pages >> 5]; // touched since last save
c3_w pag_w; // number of pages (<= u3a_pages)
c3_w gar_w; // guard page
u3e_image nor_u; // north segment
u3e_image sou_u; // south segment
} u3e_pool;
/* u3e_flaw: loom fault result.
*/
typedef enum {
u3e_flaw_sham = 0, // bogus state
u3e_flaw_base = 1, // vm fail (mprotect)
u3e_flaw_meme = 2, // bail:meme
u3e_flaw_good = 3 // handled
} u3e_flaw;
/** Globals.
**/
/// Snapshotting system.
extern u3e_pool u3e_Pool;
# define u3P u3e_Pool
/** Constants.
**/
/** Functions.
**/
/* u3e_backup(): copy the snapshot from [pux_c] to [pax_c],
* overwriting optional.
*/
c3_o
u3e_backup(c3_c* pux_c, c3_c* pax_c, c3_o ovw_o);
/* u3e_fault(): handle a memory fault.
*/
u3e_flaw
u3e_fault(u3_post low_p, u3_post hig_p, u3_post off_p);
/* u3e_save(): update the checkpoint.
*/
void
u3e_save(u3_post low_p, u3_post hig_p);
/* u3e_toss(): discard ephemeral pages.
*/
void
u3e_toss(u3_post low_p, u3_post hig_p);
/* u3e_live(): start the persistence system. Return c3y if no image.
*/
c3_o
u3e_live(c3_o nuu_o, c3_c* dir_c);
/* u3e_stop(): gracefully stop the persistence system.
*/
void
u3e_stop(void);
/* u3e_yolo(): disable dirty page tracking, read/write whole loom.
*/
c3_o
u3e_yolo(void);
/* u3e_foul(): dirty all the pages of the loom.
*/
void
u3e_foul(void);
/* u3e_init(): initialize guard page tracking.
*/
void
u3e_init(void);
/* u3e_ward(): reposition guard page if needed.
*/
void
u3e_ward(u3_post low_p, u3_post hig_p);
#endif /* ifndef U3_EVENTS_H */
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