mariadb/newbrt/brt-internal.h

#include "cachetable.h"
#include "hashtable.h"
#include "pma.h"
#include "brt.h"
//#include "pma.h"

typedef long long diskoff;  /* Offset in a disk. -1 is the NULL pointer. */

#ifndef BRT_FANOUT
#define BRT_FANOUT 16
#endif
enum { TREE_FANOUT = BRT_FANOUT }; //, NODESIZE=1<<20 };
enum { KEY_VALUE_OVERHEAD = 8 }; /* Must store the two lengths. */
struct nodeheader_in_file {
    int n_in_buffer;
    
};
enum { BUFFER_HEADER_SIZE = (4 // height//
			     + 4 // n_children
			     + TREE_FANOUT * 8 // children
			     ) };
typedef struct brtnode *BRTNODE;
/* Internal nodes. */
struct brtnode {
    enum typ_tag tag;
    unsigned int nodesize;
    diskoff thisnodename;
    int    height; /* height is always >= 0.  0 for leaf, >0 for nonleaf. */
    union node {
	struct nonleaf {
	    int             n_children;  /* if n_children==TREE_FANOUT+1 then the tree needs to be rebalanced. */
	    bytevec         childkeys[TREE_FANOUT];   /* Pivot keys.  Child 0's keys are <= childkeys[0].  Child 1's keys are <= childkeys[1].
							 Note: It is possible that Child 1's keys are == to child 0's key's, so it is
							 not necessarily true that child 1's keys are > childkeys[0].
						         However, in the absense of duplicate keys, child 1's keys *are* > childkeys[0]. */
	    unsigned int    childkeylens[TREE_FANOUT];
	    unsigned int    totalchildkeylens;
	    diskoff         children[TREE_FANOUT+1];  /* unused if height==0 */   /* Note: The last element of these arrays is used only temporarily while splitting a node. */
	    HASHTABLE       htables[TREE_FANOUT+1];
	    unsigned int    n_bytes_in_hashtable[TREE_FANOUT+1]; /* how many bytes are in each hashtable (including overheads) */
	    unsigned int    n_bytes_in_hashtables;
            unsigned int    n_cursors[TREE_FANOUT+1];
        } n;
	struct leaf {
	    PMA buffer;
	    unsigned int n_bytes_in_buffer;
	} l;
    } u;
};

struct brt_header {
    int dirty;
    unsigned int nodesize;
    diskoff freelist;
    diskoff unused_memory;
    diskoff unnamed_root;
    int n_named_roots; /* -1 if the only one is unnamed */
    char  **names;
    diskoff *roots;
};


struct brt {
    CACHEFILE cf;
    char *database_name;
    // The header is shared.  It is also ephemeral.
    struct brt_header *h;

    BRT_CURSOR cursors_head, cursors_tail;

    int (*compare_fun)(DB*,const DBT*,const DBT*);

    void *skey,*sval; /* Used for DBT return values. */
};

/* serialization code */
int serialize_brtnode_to(int fd, diskoff off, diskoff size, BRTNODE node);
int deserialize_brtnode_from (int fd, diskoff off, BRTNODE *brtnode, int nodesize);
unsigned int serialize_brtnode_size(BRTNODE node); /* How much space will it take? */
int keycompare (bytevec key1, ITEMLEN key1len, bytevec key2, ITEMLEN key2len);

void verify_counts(BRTNODE);

int serialize_brt_header_to (int fd, struct brt_header *h);
int deserialize_brtheader_from (int fd, diskoff off, struct brt_header **brth);

void brtnode_free (BRTNODE *node);

//static inline int brtnode_n_hashtables(BRTNODE node) { if (node->height==0) return 1; else return node->u.n.n_children; }

//int write_brt_header (int fd, struct brt_header *header);

#if 1
#define DEADBEEF ((void*)0xDEADBEEF)
#else
#define DEADBEEF ((void*)0xDEADBEEFDEADBEEF)
#endif


#define CURSOR_PATHLEN_LIMIT 256
struct brt_cursor {
    BRT brt;
    int path_len;  /* -1 if the cursor points nowhere. */
    BRTNODE path[CURSOR_PATHLEN_LIMIT]; /* Include the leaf (last).    These are all pinned. */
    int pathcnum[CURSOR_PATHLEN_LIMIT]; /* which child did we descend to from here? */
    PMA_CURSOR pmacurs; /* The cursor into the leaf.  NULL if the cursor doesn't exist. */
    BRT_CURSOR prev,next;
};

/* print the cursor path */
void brt_cursor_print(BRT_CURSOR cursor);

/* is the cursor path empty? */
static inline int brt_cursor_path_empty(BRT_CURSOR cursor) {
    return cursor->path_len == 0;
}

/*is the cursor path full? */
static inline int brt_cursor_path_full(BRT_CURSOR cursor) {
    return cursor->path_len == CURSOR_PATHLEN_LIMIT;
}

static inline int brt_cursor_active(BRT_CURSOR cursor) {
    return cursor->path_len > 0;
}

/* brt has a new root.  add the root to this cursor. */
void brt_cursor_new_root(BRT_CURSOR cursor, BRT t, BRTNODE newroot, BRTNODE left, BRTNODE right);

/* a brt leaf has split.  modify this cursor if it includes the old node in its path. */
void brt_cursor_leaf_split(BRT_CURSOR cursor, BRT t, BRTNODE oldnode, BRTNODE left, BRTNODE right);

/* a brt internal node has expanded.  modify this cursor if it includes the  old node in its path. */
void brt_cursor_nonleaf_expand(BRT_CURSOR cursor, BRT t, BRTNODE oldnode, int childnum, BRTNODE left, BRTNODE right);

/* a brt internal node has split.  modify this cursor if it includes the old node in its path. */
void brt_cursor_nonleaf_split(BRT_CURSOR cursor, BRT t, BRTNODE oldnode, BRTNODE left, BRTNODE right);

void brt_update_cursors_new_root(BRT t, BRTNODE newroot, BRTNODE left, BRTNODE right);
void brt_update_cursors_leaf_split(BRT t, BRTNODE oldnode, BRTNODE left, BRTNODE right);
void brt_update_cursors_nonleaf_expand(BRT t, BRTNODE oldnode, int childnum, BRTNODE left, BRTNODE right);
void brt_update_cursors_nonleaf_split(BRT t, BRTNODE oldnode, BRTNODE left, BRTNODE right);