/*
* __wt_verify_dsk_image --
* Verify a single block as read from disk.
*/
int
__wt_verify_dsk_image(WT_SESSION_IMPL *session,
const char *tag, const WT_PAGE_HEADER *dsk, size_t size, int empty_page_ok)
{
const uint8_t *p, *end;
u_int i;
uint8_t flags;
/* Check the page type. */
switch (dsk->type) {
case WT_PAGE_BLOCK_MANAGER:
case WT_PAGE_COL_FIX:
case WT_PAGE_COL_INT:
case WT_PAGE_COL_VAR:
case WT_PAGE_OVFL:
case WT_PAGE_ROW_INT:
case WT_PAGE_ROW_LEAF:
break;
case WT_PAGE_INVALID:
default:
WT_RET_VRFY(session,
"page at %s has an invalid type of %" PRIu32,
tag, dsk->type);
}
/* Check the page record number. */
switch (dsk->type) {
case WT_PAGE_COL_FIX:
case WT_PAGE_COL_INT:
case WT_PAGE_COL_VAR:
if (dsk->recno != 0)
break;
WT_RET_VRFY(session,
"%s page at %s has a record number of zero",
__wt_page_type_string(dsk->type), tag);
case WT_PAGE_BLOCK_MANAGER:
case WT_PAGE_OVFL:
case WT_PAGE_ROW_INT:
case WT_PAGE_ROW_LEAF:
if (dsk->recno == 0)
break;
WT_RET_VRFY(session,
"%s page at %s has a non-zero record number",
__wt_page_type_string(dsk->type), tag);
}
/* Check the page flags. */
flags = dsk->flags;
if (LF_ISSET(WT_PAGE_COMPRESSED))
LF_CLR(WT_PAGE_COMPRESSED);
if (LF_ISSET(WT_PAGE_ENCRYPTED))
LF_CLR(WT_PAGE_ENCRYPTED);
if (dsk->type == WT_PAGE_ROW_LEAF) {
if (LF_ISSET(WT_PAGE_EMPTY_V_ALL) &&
LF_ISSET(WT_PAGE_EMPTY_V_NONE))
WT_RET_VRFY(session,
"page at %s has invalid flags combination: 0x%"
PRIx8,
tag, dsk->flags);
if (LF_ISSET(WT_PAGE_EMPTY_V_ALL))
LF_CLR(WT_PAGE_EMPTY_V_ALL);
if (LF_ISSET(WT_PAGE_EMPTY_V_NONE))
LF_CLR(WT_PAGE_EMPTY_V_NONE);
}
if (flags != 0)
WT_RET_VRFY(session,
"page at %s has invalid flags set: 0x%" PRIx8,
tag, flags);
/* Unused bytes */
for (p = dsk->unused, i = sizeof(dsk->unused); i > 0; --i)
if (*p != '\0')
WT_RET_VRFY(session,
"page at %s has non-zero unused page header bytes",
tag);
/*
* Any bytes after the data chunk should be nul bytes; ignore if the
* size is 0, that allows easy checking of disk images where we don't
* have the size.
*/
if (size != 0) {
p = (uint8_t *)dsk + dsk->mem_size;
end = (uint8_t *)dsk + size;
for (; p < end; ++p)
if (*p != '\0')
WT_RET_VRFY(session,
"%s page at %s has non-zero trailing bytes",
__wt_page_type_string(dsk->type), tag);
}
/* Check for empty pages, then verify the items on the page. */
switch (dsk->type) {
case WT_PAGE_COL_INT:
case WT_PAGE_COL_FIX:
case WT_PAGE_COL_VAR:
case WT_PAGE_ROW_INT:
case WT_PAGE_ROW_LEAF:
if (!empty_page_ok && dsk->u.entries == 0)
WT_RET_VRFY(session, "%s page at %s has no entries",
__wt_page_type_string(dsk->type), tag);
break;
case WT_PAGE_BLOCK_MANAGER:
case WT_PAGE_OVFL:
if (dsk->u.datalen == 0)
WT_RET_VRFY(session, "%s page at %s has no data",
__wt_page_type_string(dsk->type), tag);
break;
}
switch (dsk->type) {
case WT_PAGE_COL_INT:
return (__verify_dsk_col_int(session, tag, dsk));
case WT_PAGE_COL_FIX:
return (__verify_dsk_col_fix(session, tag, dsk));
case WT_PAGE_COL_VAR:
return (__verify_dsk_col_var(session, tag, dsk));
case WT_PAGE_ROW_INT:
case WT_PAGE_ROW_LEAF:
return (__verify_dsk_row(session, tag, dsk));
case WT_PAGE_BLOCK_MANAGER:
case WT_PAGE_OVFL:
return (__verify_dsk_chunk(session, tag, dsk, dsk->u.datalen));
WT_ILLEGAL_VALUE(session);
}
/* NOTREACHED */
}
/*
* editor --
* Main editor routine.
*
* PUBLIC: int editor(GS *, int, char *[]);
*/
int
editor(GS *gp, int argc, char *argv[])
{
extern int optind;
extern char *optarg;
const char *p;
EVENT ev;
FREF *frp;
SCR *sp;
size_t len;
u_int flags;
int ch, flagchk, lflag, secure, startup, readonly, rval, silent;
char *tag_f, *wsizearg, path[256];
CHAR_T *w;
size_t wlen;
/* Initialize the busy routine, if not defined by the screen. */
if (gp->scr_busy == NULL)
gp->scr_busy = vs_busy;
/* Initialize the message routine, if not defined by the screen. */
if (gp->scr_msg == NULL)
gp->scr_msg = vs_msg;
gp->catd = (nl_catd)-1;
/* Common global structure initialization. */
TAILQ_INIT(gp->dq);
TAILQ_INIT(gp->hq);
SLIST_INIT(gp->ecq);
SLIST_INSERT_HEAD(gp->ecq, &gp->excmd, q);
gp->noprint = DEFAULT_NOPRINT;
/* Structures shared by screens so stored in the GS structure. */
TAILQ_INIT(gp->frefq);
TAILQ_INIT(gp->dcb_store.textq);
SLIST_INIT(gp->cutq);
SLIST_INIT(gp->seqq);
/* Set initial screen type and mode based on the program name. */
readonly = 0;
if (!strcmp(getprogname(), "ex") || !strcmp(getprogname(), "nex"))
LF_INIT(SC_EX);
else {
/* Nview, view are readonly. */
if (!strcmp(getprogname(), "nview") ||
!strcmp(getprogname(), "view"))
readonly = 1;
/* Vi is the default. */
LF_INIT(SC_VI);
}
/* Convert old-style arguments into new-style ones. */
if (v_obsolete(argv))
return (1);
/* Parse the arguments. */
flagchk = '\0';
tag_f = wsizearg = NULL;
lflag = secure = silent = 0;
startup = 1;
/* Set the file snapshot flag. */
F_SET(gp, G_SNAPSHOT);
#ifdef DEBUG
while ((ch = getopt(argc, argv, "c:D:eFlRrSsT:t:vw:")) != EOF)
#else
while ((ch = getopt(argc, argv, "c:eFlRrSst:vw:")) != EOF)
#endif
switch (ch) {
case 'c': /* Run the command. */
/*
* XXX
* We should support multiple -c options.
*/
if (gp->c_option != NULL) {
warnx("only one -c command may be specified.");
return (1);
}
gp->c_option = optarg;
break;
#ifdef DEBUG
case 'D':
switch (optarg[0]) {
case 's':
startup = 0;
break;
case 'w':
attach(gp);
break;
default:
warnx("usage: -D requires s or w argument.");
return (1);
}
break;
#endif
case 'e': /* Ex mode. */
LF_CLR(SC_VI);
LF_SET(SC_EX);
break;
case 'F': /* No snapshot. */
F_CLR(gp, G_SNAPSHOT);
break;
case 'l': /* Set lisp, showmatch options. */
lflag = 1;
break;
case 'R': /* Readonly. */
readonly = 1;
break;
case 'r': /* Recover. */
if (flagchk == 't') {
warnx("only one of -r and -t may be specified.");
return (1);
}
flagchk = 'r';
break;
case 'S':
secure = 1;
break;
case 's':
silent = 1;
break;
#ifdef DEBUG
case 'T': /* Trace. */
if ((gp->tracefp = fopen(optarg, "w")) == NULL) {
warn("%s", optarg);
goto err;
}
(void)fprintf(gp->tracefp,
"\n===\ntrace: open %s\n", optarg);
break;
#endif
case 't': /* Tag. */
if (flagchk == 'r') {
warnx("only one of -r and -t may be specified.");
return (1);
}
if (flagchk == 't') {
warnx("only one tag file may be specified.");
return (1);
}
flagchk = 't';
tag_f = optarg;
break;
case 'v': /* Vi mode. */
LF_CLR(SC_EX);
LF_SET(SC_VI);
break;
case 'w':
wsizearg = optarg;
break;
case '?':
default:
(void)gp->scr_usage();
return (1);
}
argc -= optind;
argv += optind;
/*
* -s option is only meaningful to ex.
*
* If not reading from a terminal, it's like -s was specified.
*/
if (silent && !LF_ISSET(SC_EX)) {
warnx("-s option is only applicable to ex.");
goto err;
}
if (LF_ISSET(SC_EX) && F_ISSET(gp, G_SCRIPTED))
silent = 1;
/*
* Build and initialize the first/current screen. This is a bit
* tricky. If an error is returned, we may or may not have a
* screen structure. If we have a screen structure, put it on a
* display queue so that the error messages get displayed.
*
* !!!
* Everything we do until we go interactive is done in ex mode.
*/
if (screen_init(gp, NULL, &sp)) {
if (sp != NULL)
TAILQ_INSERT_HEAD(gp->dq, sp, q);
goto err;
}
F_SET(sp, SC_EX);
TAILQ_INSERT_HEAD(gp->dq, sp, q);
if (v_key_init(sp)) /* Special key initialization. */
goto err;
{ int oargs[5], *oargp = oargs;
if (lflag) { /* Command-line options. */
*oargp++ = O_LISP;
*oargp++ = O_SHOWMATCH;
}
if (readonly)
*oargp++ = O_READONLY;
if (secure)
*oargp++ = O_SECURE;
*oargp = -1; /* Options initialization. */
if (opts_init(sp, oargs))
goto err;
}
if (wsizearg != NULL) {
ARGS *av[2], a, b;
(void)snprintf(path, sizeof(path), "window=%s", wsizearg);
a.bp = (CHAR_T *)path;
a.len = strlen(path);
b.bp = NULL;
b.len = 0;
av[0] = &a;
av[1] = &b;
(void)opts_set(sp, av, NULL);
}
if (silent) { /* Ex batch mode option values. */
O_CLR(sp, O_AUTOPRINT);
O_CLR(sp, O_PROMPT);
O_CLR(sp, O_VERBOSE);
O_CLR(sp, O_WARN);
F_SET(sp, SC_EX_SILENT);
}
sp->rows = O_VAL(sp, O_LINES); /* Make ex formatting work. */
sp->cols = O_VAL(sp, O_COLUMNS);
if (!silent && startup) { /* Read EXINIT, exrc files. */
if (ex_exrc(sp))
goto err;
if (F_ISSET(sp, SC_EXIT | SC_EXIT_FORCE)) {
if (screen_end(sp))
goto err;
goto done;
}
}
/*
* List recovery files if -r specified without file arguments.
* Note, options must be initialized and startup information
* read before doing this.
*/
if (flagchk == 'r' && argv[0] == NULL) {
if (rcv_list(sp))
goto err;
if (screen_end(sp))
goto err;
goto done;
}
/*
* !!!
* Initialize the default ^D, ^U scrolling value here, after the
* user has had every opportunity to set the window option.
*
* It's historic practice that changing the value of the window
* option did not alter the default scrolling value, only giving
* a count to ^D/^U did that.
*/
sp->defscroll = (O_VAL(sp, O_WINDOW) + 1) / 2;
/*
* If we don't have a command-line option, switch into the right
* editor now, so that we position default files correctly, and
* so that any tags file file-already-locked messages are in the
* vi screen, not the ex screen.
*
* XXX
* If we have a command-line option, the error message can end
* up in the wrong place, but I think that the combination is
* unlikely.
*/
if (gp->c_option == NULL) {
F_CLR(sp, SC_EX | SC_VI);
F_SET(sp, LF_ISSET(SC_EX | SC_VI));
}
/* Open a tag file if specified. */
if (tag_f != NULL) {
CHAR2INT(sp, tag_f, strlen(tag_f) + 1, w, wlen);
if (ex_tag_first(sp, w))
goto err;
}
/*
* Append any remaining arguments as file names. Files are recovery
* files if -r specified. If the tag option or ex startup commands
* loaded a file, then any file arguments are going to come after it.
*/
if (*argv != NULL) {
if (sp->frp != NULL) {
/* Cheat -- we know we have an extra argv slot. */
*--argv = strdup(sp->frp->name);
if (*argv == NULL) {
warn(NULL);
goto err;
}
}
sp->argv = sp->cargv = argv;
F_SET(sp, SC_ARGNOFREE);
if (flagchk == 'r')
F_SET(sp, SC_ARGRECOVER);
}
/*
* If the ex startup commands and or/the tag option haven't already
* created a file, create one. If no command-line files were given,
* use a temporary file.
*/
if (sp->frp == NULL) {
if (sp->argv == NULL) {
if ((frp = file_add(sp, NULL)) == NULL)
goto err;
} else {
if ((frp = file_add(sp, sp->argv[0])) == NULL)
goto err;
if (F_ISSET(sp, SC_ARGRECOVER))
F_SET(frp, FR_RECOVER);
}
if (file_init(sp, frp, NULL, 0))
goto err;
if (EXCMD_RUNNING(gp)) {
(void)ex_cmd(sp);
if (F_ISSET(sp, SC_EXIT | SC_EXIT_FORCE)) {
if (screen_end(sp))
goto err;
goto done;
}
}
}
/*
* Check to see if we need to wait for ex. If SC_SCR_EX is set, ex
* was forced to initialize the screen during startup. We'd like to
* wait for a single character from the user, but we can't because
* we're not in raw mode. We can't switch to raw mode because the
* vi initialization will switch to xterm's alternate screen, causing
* us to lose the messages we're pausing to make sure the user read.
* So, wait for a complete line.
*/
if (F_ISSET(sp, SC_SCR_EX)) {
p = msg_cmsg(sp, CMSG_CONT_R, &len);
(void)write(STDOUT_FILENO, p, len);
for (;;) {
if (v_event_get(sp, &ev, 0, 0))
goto err;
if (ev.e_event == E_INTERRUPT ||
(ev.e_event == E_CHARACTER &&
(ev.e_value == K_CR || ev.e_value == K_NL)))
break;
(void)gp->scr_bell(sp);
}
}
/* Switch into the right editor, regardless. */
F_CLR(sp, SC_EX | SC_VI);
F_SET(sp, LF_ISSET(SC_EX | SC_VI) | SC_STATUS_CNT);
/*
* Main edit loop. Vi handles split screens itself, we only return
* here when switching editor modes or restarting the screen.
*/
while (sp != NULL)
if (F_ISSET(sp, SC_EX) ? ex(&sp) : vi(&sp))
goto err;
done: rval = 0;
if (0)
err: rval = 1;
/* Clean out the global structure. */
v_end(gp);
return (rval);
}
/*
* ex_txt --
* Get lines from the terminal for ex.
*
* PUBLIC: int ex_txt(SCR *, TEXTH *, ARG_CHAR_T, u_int32_t);
*/
int
ex_txt(SCR *sp, TEXTH *tiqh, ARG_CHAR_T prompt, u_int32_t flags)
{
EVENT ev;
GS *gp;
TEXT ait, *ntp, *tp;
carat_t carat_st;
size_t cnt;
int rval;
int nochange;
rval = 0;
/*
* Get a TEXT structure with some initial buffer space, reusing the
* last one if it's big enough. (All TEXT bookkeeping fields default
* to 0 -- text_init() handles this.)
*/
if (!TAILQ_EMPTY(tiqh)) {
tp = TAILQ_FIRST(tiqh);
if (TAILQ_NEXT(tp, q) != NULL || tp->lb_len < 32) {
text_lfree(tiqh);
goto newtp;
}
tp->len = 0;
} else {
newtp: if ((tp = text_init(sp, NULL, 0, 32)) == NULL)
goto err;
TAILQ_INSERT_HEAD(tiqh, tp, q);
}
/* Set the starting line number. */
tp->lno = sp->lno + 1;
/*
* If it's a terminal, set up autoindent, put out the prompt, and
* set it up so we know we were suspended. Otherwise, turn off
* the autoindent flag, as that requires less special casing below.
*
* XXX
* Historic practice is that ^Z suspended command mode (but, because
* it ran in cooked mode, it was unaffected by the autowrite option.)
* On restart, any "current" input was discarded, whether in insert
* mode or not, and ex was in command mode. This code matches historic
* practice, but not 'cause it's easier.
*/
gp = sp->gp;
if (F_ISSET(gp, G_SCRIPTED))
LF_CLR(TXT_AUTOINDENT);
else {
if (LF_ISSET(TXT_AUTOINDENT)) {
LF_SET(TXT_EOFCHAR);
if (v_txt_auto(sp, sp->lno, NULL, 0, tp))
goto err;
}
txt_prompt(sp, tp, prompt, flags);
}
for (carat_st = C_NOTSET, nochange = 0;;) {
if (v_event_get(sp, &ev, 0, 0))
goto err;
/* Deal with all non-character events. */
switch (ev.e_event) {
case E_CHARACTER:
break;
case E_ERR:
goto err;
case E_REPAINT:
case E_WRESIZE:
continue;
case E_EOF:
rval = 1;
/* FALLTHROUGH */
case E_INTERRUPT:
/*
* Handle EOF/SIGINT events by discarding partially
* entered text and returning. EOF returns failure,
* E_INTERRUPT returns success.
*/
goto notlast;
default:
v_event_err(sp, &ev);
goto notlast;
}
/*
* Deal with character events.
*
* Check to see if the character fits into the input buffer.
* (Use tp->len, ignore overwrite and non-printable chars.)
*/
BINC_GOTOW(sp, tp->lb, tp->lb_len, tp->len + 1);
switch (ev.e_value) {
case K_CR:
/*
* !!!
* Historically, <carriage-return>'s in the command
* weren't special, so the ex parser would return an
* unknown command error message. However, if they
* terminated the command if they were in a map. I'm
* pretty sure this still isn't right, but it handles
* what I've seen so far.
*/
if (!F_ISSET(&ev.e_ch, CH_MAPPED))
goto ins_ch;
/* FALLTHROUGH */
case K_NL:
/*
* '\' can escape <carriage-return>/<newline>. We
* don't discard the backslash because we need it
* to get the <newline> through the ex parser.
*/
if (LF_ISSET(TXT_BACKSLASH) &&
tp->len != 0 && tp->lb[tp->len - 1] == '\\')
goto ins_ch;
/*
* CR returns from the ex command line.
*
* XXX
* Terminate with a nul, needed by filter.
*/
if (LF_ISSET(TXT_CR)) {
tp->lb[tp->len] = '\0';
goto done;
}
/*
* '.' may terminate text input mode; free the current
* TEXT.
*/
if (LF_ISSET(TXT_DOTTERM) && tp->len == tp->ai + 1 &&
tp->lb[tp->len - 1] == '.') {
notlast: TAILQ_REMOVE(tiqh, tp, q);
text_free(tp);
goto done;
}
/* Set up bookkeeping for the new line. */
if ((ntp = text_init(sp, NULL, 0, 32)) == NULL)
goto err;
ntp->lno = tp->lno + 1;
/*
* Reset the autoindent line value. 0^D keeps the ai
* line from changing, ^D changes the level, even if
* there were no characters in the old line. Note, if
* using the current tp structure, use the cursor as
* the length, the autoindent characters may have been
* erased.
*/
if (LF_ISSET(TXT_AUTOINDENT)) {
if (nochange) {
nochange = 0;
if (v_txt_auto(sp,
OOBLNO, &ait, ait.ai, ntp))
goto err;
free(ait.lb);
} else
if (v_txt_auto(sp,
OOBLNO, tp, tp->len, ntp))
goto err;
carat_st = C_NOTSET;
}
txt_prompt(sp, ntp, prompt, flags);
/*
* Swap old and new TEXT's, and insert the new TEXT
* into the queue.
*/
tp = ntp;
TAILQ_INSERT_TAIL(tiqh, tp, q);
break;
case K_CARAT: /* Delete autoindent chars. */
if (tp->len <= tp->ai && LF_ISSET(TXT_AUTOINDENT))
carat_st = C_CARATSET;
goto ins_ch;
case K_ZERO: /* Delete autoindent chars. */
if (tp->len <= tp->ai && LF_ISSET(TXT_AUTOINDENT))
carat_st = C_ZEROSET;
goto ins_ch;
case K_CNTRLD: /* Delete autoindent char. */
/*
* !!!
* Historically, the ^D command took (but then ignored)
* a count. For simplicity, we don't return it unless
* it's the first character entered. The check for len
* equal to 0 is okay, TXT_AUTOINDENT won't be set.
*/
if (LF_ISSET(TXT_CNTRLD)) {
for (cnt = 0; cnt < tp->len; ++cnt)
if (!isblank(tp->lb[cnt]))
break;
if (cnt == tp->len) {
tp->len = 1;
tp->lb[0] = ev.e_c;
tp->lb[1] = '\0';
/*
* Put out a line separator, in case
* the command fails.
*/
(void)putchar('\n');
goto done;
}
}
/*
* POSIX 1003.1b-1993, paragraph 7.1.1.9, states that
* the EOF characters are discarded if there are other
* characters to process in the line, i.e. if the EOF
* is not the first character in the line. For this
* reason, historic ex discarded the EOF characters,
* even if occurring in the middle of the input line.
* We match that historic practice.
*
* !!!
* The test for discarding in the middle of the line is
* done in the switch, because the CARAT forms are N+1,
* not N.
*
* !!!
* There's considerable magic to make the terminal code
* return the EOF character at all. See that code for
* details.
*/
if (!LF_ISSET(TXT_AUTOINDENT) || tp->len == 0)
continue;
switch (carat_st) {
case C_CARATSET: /* ^^D */
if (tp->len > tp->ai + 1)
continue;
/* Save the ai string for later. */
ait.lb = NULL;
ait.lb_len = 0;
BINC_GOTOW(sp, ait.lb, ait.lb_len, tp->ai);
MEMCPY(ait.lb, tp->lb, tp->ai);
ait.ai = ait.len = tp->ai;
carat_st = C_NOTSET;
nochange = 1;
goto leftmargin;
case C_ZEROSET: /* 0^D */
if (tp->len > tp->ai + 1)
continue;
carat_st = C_NOTSET;
leftmargin: (void)gp->scr_ex_adjust(sp, EX_TERM_CE);
tp->ai = tp->len = 0;
break;
case C_NOTSET: /* ^D */
if (tp->len > tp->ai)
continue;
if (txt_dent(sp, tp))
goto err;
break;
default:
abort();
}
/* Clear and redisplay the line. */
(void)gp->scr_ex_adjust(sp, EX_TERM_CE);
txt_prompt(sp, tp, prompt, flags);
break;
default:
/*
* See the TXT_BEAUTIFY comment in vi/v_txt_ev.c.
*
* Silently eliminate any iscntrl() character that was
* not already handled specially, except for <tab> and
* <ff>.
*/
ins_ch: if (LF_ISSET(TXT_BEAUTIFY) && ISCNTRL(ev.e_c) &&
ev.e_value != K_FORMFEED && ev.e_value != K_TAB)
break;
tp->lb[tp->len++] = ev.e_c;
break;
}
}
/* NOTREACHED */
done: return (rval);
err:
alloc_err:
return (1);
}
/*
* __tree_walk_internal --
* Move to the next/previous page in the tree.
*/
static inline int
__tree_walk_internal(WT_SESSION_IMPL *session,
WT_REF **refp, uint64_t *walkcntp,
int (*skip_func)(WT_SESSION_IMPL *, WT_REF *, void *, bool *),
void *func_cookie, uint32_t flags)
{
WT_BTREE *btree;
WT_DECL_RET;
WT_PAGE_INDEX *pindex;
WT_REF *couple, *couple_orig, *ref;
uint32_t slot;
bool empty_internal, initial_descent, prev, skip;
btree = S2BT(session);
pindex = NULL;
empty_internal = initial_descent = false;
/*
* Tree walks are special: they look inside page structures that splits
* may want to free. Publish that the tree is active during this
* window.
*/
WT_ENTER_PAGE_INDEX(session);
/* Walk should never instantiate deleted pages. */
LF_SET(WT_READ_NO_EMPTY);
/*
* !!!
* Fast-truncate currently only works on row-store trees.
*/
if (btree->type != BTREE_ROW)
LF_CLR(WT_READ_TRUNCATE);
prev = LF_ISSET(WT_READ_PREV) ? 1 : 0;
/*
* There are multiple reasons and approaches to walking the in-memory
* tree:
*
* (1) finding pages to evict (the eviction server);
* (2) writing just dirty leaves or internal nodes (checkpoint);
* (3) discarding pages (close);
* (4) truncating pages in a range (fast truncate);
* (5) skipping pages based on outside information (compaction);
* (6) cursor scans (applications).
*
* Except for cursor scans and compaction, the walk is limited to the
* cache, no pages are read. In all cases, hazard pointers protect the
* walked pages from eviction.
*
* Walks use hazard-pointer coupling through the tree and that's OK
* (hazard pointers can't deadlock, so there's none of the usual
* problems found when logically locking up a btree). If the eviction
* thread tries to evict the active page, it fails because of our
* hazard pointer. If eviction tries to evict our parent, that fails
* because the parent has a child page that can't be discarded. We do
* play one game: don't couple up to our parent and then back down to a
* new leaf, couple to the next page to which we're descending, it
* saves a hazard-pointer swap for each cursor page movement.
*
* !!!
* NOTE: we depend on the fact it's OK to release a page we don't hold,
* that is, it's OK to release couple when couple is set to NULL.
*
* Take a copy of any held page and clear the return value. Remember
* the hazard pointer we're currently holding.
*
* Clear the returned value, it makes future error handling easier.
*/
couple = couple_orig = ref = *refp;
*refp = NULL;
/* If no page is active, begin a walk from the start/end of the tree. */
if (ref == NULL) {
restart: /*
* We can be here with a NULL or root WT_REF; the page release
* function handles them internally, don't complicate this code
* by calling them out.
*/
WT_ERR(__wt_page_release(session, couple, flags));
/*
* We're not supposed to walk trees without root pages. As this
* has not always been the case, assert to debug that change.
*/
WT_ASSERT(session, btree->root.page != NULL);
couple = couple_orig = ref = &btree->root;
initial_descent = true;
goto descend;
}
/*
* If the active page was the root, we've reached the walk's end; we
* only get here if we've returned the root to our caller, so we're
* holding no hazard pointers.
*/
if (__wt_ref_is_root(ref))
goto done;
/* Figure out the current slot in the WT_REF array. */
__ref_index_slot(session, ref, &pindex, &slot);
for (;;) {
/*
* If we're at the last/first slot on the internal page, return
* it in post-order traversal. Otherwise move to the next/prev
* slot and left/right-most element in that subtree.
*/
while ((prev && slot == 0) ||
(!prev && slot == pindex->entries - 1)) {
/* Ascend to the parent. */
__ref_ascend(session, &ref, &pindex, &slot);
/*
* If at the root and returning internal pages, return
* the root page, otherwise we're done. Regardless, no
* hazard pointer is required, release the one we hold.
*/
if (__wt_ref_is_root(ref)) {
WT_ERR(__wt_page_release(
session, couple, flags));
if (!LF_ISSET(WT_READ_SKIP_INTL))
*refp = ref;
goto done;
}
/*
* If we got all the way through an internal page and
* all of the child pages were deleted, mark it for
* eviction.
*/
if (empty_internal && pindex->entries > 1) {
__wt_page_evict_soon(session, ref);
empty_internal = false;
}
/*
* Optionally return internal pages. Swap our previous
* hazard pointer for the page we'll return. We don't
* handle restart or not-found returns, it would require
* additional complexity and is not a possible return:
* we're moving to the parent of the current child page,
* the parent can't have been evicted.
*/
if (!LF_ISSET(WT_READ_SKIP_INTL)) {
WT_ERR(__wt_page_swap(
session, couple, ref, flags));
*refp = ref;
goto done;
}
}
if (prev)
--slot;
else
++slot;
if (walkcntp != NULL)
++*walkcntp;
for (;;) {
/*
* Move to the next slot, and set the reference hint if
* it's wrong (used when we continue the walk). We don't
* always update the hints when splitting, it's expected
* for them to be incorrect in some workloads.
*/
ref = pindex->index[slot];
if (ref->pindex_hint != slot)
ref->pindex_hint = slot;
/*
* If we see any child states other than deleted, the
* page isn't empty.
*/
if (ref->state != WT_REF_DELETED &&
!LF_ISSET(WT_READ_TRUNCATE))
empty_internal = false;
if (LF_ISSET(WT_READ_CACHE)) {
/*
* Only look at unlocked pages in memory:
* fast-path some common cases.
*/
if (LF_ISSET(WT_READ_NO_WAIT) &&
ref->state != WT_REF_MEM)
break;
/* Skip lookaside pages if not requested. */
if (ref->state == WT_REF_LOOKASIDE &&
!LF_ISSET(WT_READ_LOOKASIDE))
break;
} else if (LF_ISSET(WT_READ_TRUNCATE)) {
/*
* Avoid pulling a deleted page back in to try
* to delete it again.
*/
if (ref->state == WT_REF_DELETED &&
__wt_delete_page_skip(session, ref, false))
break;
/*
* If deleting a range, try to delete the page
* without instantiating it.
*/
WT_ERR(__wt_delete_page(session, ref, &skip));
if (skip)
break;
empty_internal = false;
} else if (skip_func != NULL) {
WT_ERR(skip_func(session,
ref, func_cookie, &skip));
if (skip)
break;
} else {
/*
* Try to skip deleted pages visible to us.
*/
if (ref->state == WT_REF_DELETED &&
__wt_delete_page_skip(session, ref, false))
break;
}
ret = __wt_page_swap(session, couple, ref,
WT_READ_NOTFOUND_OK | WT_READ_RESTART_OK | flags);
/*
* Not-found is an expected return when only walking
* in-cache pages, or if we see a deleted page.
*/
if (ret == WT_NOTFOUND) {
ret = 0;
break;
}
/*
* The page we're moving to might have split, in which
* case move to the last position we held.
*/
if (ret == WT_RESTART) {
ret = 0;
/*
* If a cursor is setting up at the end of the
* tree, we can't use our parent page's index,
* because it may have already split; restart
* the walk.
*/
if (prev && initial_descent)
goto restart;
/*
* If a new walk that never coupled from the
* root to a new saved position in the tree,
* restart the walk.
*/
if (couple == &btree->root)
goto restart;
/*
* If restarting from some original position,
* repeat the increment or decrement we made at
* that time. Otherwise, couple is an internal
* page we've acquired after moving from that
* starting position and we can treat it as a
* new page. This works because we never acquire
* a hazard pointer on a leaf page we're not
* going to return to our caller, this will quit
* working if that ever changes.
*/
WT_ASSERT(session,
couple == couple_orig ||
WT_PAGE_IS_INTERNAL(couple->page));
ref = couple;
__ref_index_slot(session, ref, &pindex, &slot);
if (couple == couple_orig)
break;
}
WT_ERR(ret);
couple = ref;
/*
* A new page: configure for traversal of any internal
* page's children, else return the leaf page.
*/
if (WT_PAGE_IS_INTERNAL(ref->page)) {
descend: empty_internal = true;
/*
* There's a split race when a cursor is setting
* up at the end of the tree or moving backwards
* through the tree and descending a level. When
* splitting an internal page into its parent,
* we move the WT_REF structures and update the
* parent's page index before updating the split
* page's page index, and it's not an atomic
* update. A thread can read the parent page's
* replacement page index, then read the split
* page's original index, or the parent page's
* original and the split page's replacement.
*
* This isn't a problem for a cursor setting up
* at the start of the tree or moving forwards
* through the tree because we do right-hand
* splits on internal pages and the initial part
* of the split page's namespace won't change as
* part of a split. A thread reading the parent
* page's and split page's indexes will move to
* the same slot no matter what order of indexes
* are read.
*
* Handle a cursor setting up at the end of the
* tree or moving backwards through the tree.
*/
if (!prev) {
WT_INTL_INDEX_GET(
session, ref->page, pindex);
slot = 0;
} else if (initial_descent) {
if (!__ref_initial_descent_prev(
session, ref, &pindex))
goto restart;
slot = pindex->entries - 1;
} else {
__ref_descend_prev(
session, ref, &pindex);
slot = pindex->entries - 1;
}
continue;
}
/*
* The tree-walk restart code knows we return any leaf
* page we acquire (never hazard-pointer coupling on
* after acquiring a leaf page), and asserts no restart
* happens while holding a leaf page. This page must be
* returned to our caller.
*/
*refp = ref;
goto done;
}
}
done:
err: WT_LEAVE_PAGE_INDEX(session);
return (ret);
}
/*
* __wt_tree_walk --
* Move to the next/previous page in the tree.
*/
int
__wt_tree_walk(WT_SESSION_IMPL *session,
WT_REF **refp, uint64_t *walkcntp, uint32_t flags)
{
WT_BTREE *btree;
WT_DECL_RET;
WT_PAGE *page;
WT_PAGE_INDEX *pindex;
WT_REF *couple, *couple_orig, *ref;
int prev, skip;
uint32_t slot;
btree = S2BT(session);
/*
* Tree walks are special: they look inside page structures that splits
* may want to free. Publish that the tree is active during this
* window.
*/
WT_ENTER_PAGE_INDEX(session);
/*
* !!!
* Fast-truncate currently only works on row-store trees.
*/
if (btree->type != BTREE_ROW)
LF_CLR(WT_READ_TRUNCATE);
prev = LF_ISSET(WT_READ_PREV) ? 1 : 0;
/*
* There are multiple reasons and approaches to walking the in-memory
* tree:
*
* (1) finding pages to evict (the eviction server);
* (2) writing just dirty leaves or internal nodes (checkpoint);
* (3) discarding pages (close);
* (4) truncating pages in a range (fast truncate);
* (5) skipping pages based on outside information (compaction);
* (6) cursor scans (applications).
*
* Except for cursor scans and compaction, the walk is limited to the
* cache, no pages are read. In all cases, hazard pointers protect the
* walked pages from eviction.
*
* Walks use hazard-pointer coupling through the tree and that's OK
* (hazard pointers can't deadlock, so there's none of the usual
* problems found when logically locking up a btree). If the eviction
* thread tries to evict the active page, it fails because of our
* hazard pointer. If eviction tries to evict our parent, that fails
* because the parent has a child page that can't be discarded. We do
* play one game: don't couple up to our parent and then back down to a
* new leaf, couple to the next page to which we're descending, it
* saves a hazard-pointer swap for each cursor page movement.
*
* !!!
* NOTE: we depend on the fact it's OK to release a page we don't hold,
* that is, it's OK to release couple when couple is set to NULL.
*
* Take a copy of any held page and clear the return value. Remember
* the hazard pointer we're currently holding.
*
* We may be passed a pointer to btree->evict_page that we are clearing
* here. We check when discarding pages that we're not discarding that
* page, so this clear must be done before the page is released.
*/
couple = couple_orig = ref = *refp;
*refp = NULL;
/* If no page is active, begin a walk from the start of the tree. */
if (ref == NULL) {
ref = &btree->root;
if (ref->page == NULL)
goto done;
goto descend;
}
ascend: /*
* If the active page was the root, we've reached the walk's end.
* Release any hazard-pointer we're holding.
*/
if (__wt_ref_is_root(ref)) {
WT_ERR(__wt_page_release(session, couple, flags));
goto done;
}
/* Figure out the current slot in the WT_REF array. */
__wt_page_refp(session, ref, &pindex, &slot);
for (;;) {
/*
* If we're at the last/first slot on the page, return this page
* in post-order traversal. Otherwise we move to the next/prev
* slot and left/right-most element in its subtree.
*/
if ((prev && slot == 0) ||
(!prev && slot == pindex->entries - 1)) {
ref = ref->home->pg_intl_parent_ref;
/* Optionally skip internal pages. */
if (LF_ISSET(WT_READ_SKIP_INTL))
goto ascend;
/*
* We've ascended the tree and are returning an internal
* page. If it's the root, discard our hazard pointer,
* otherwise, swap our hazard pointer for the page we'll
* return.
*/
if (__wt_ref_is_root(ref))
WT_ERR(__wt_page_release(
session, couple, flags));
else {
/*
* Locate the reference to our parent page then
* swap our child hazard pointer for the parent.
* We don't handle restart or not-found returns.
* It would require additional complexity and is
* not a possible return: we're moving to the
* parent of the current child page, our parent
* reference can't have split or been evicted.
*/
__wt_page_refp(session, ref, &pindex, &slot);
if ((ret = __wt_page_swap(
session, couple, ref, flags)) != 0) {
WT_TRET(__wt_page_release(
session, couple, flags));
WT_ERR(ret);
}
}
*refp = ref;
goto done;
}
if (prev)
--slot;
else
++slot;
if (walkcntp != NULL)
++*walkcntp;
for (;;) {
ref = pindex->index[slot];
if (LF_ISSET(WT_READ_CACHE)) {
/*
* Only look at unlocked pages in memory:
* fast-path some common cases.
*/
if (LF_ISSET(WT_READ_NO_WAIT) &&
ref->state != WT_REF_MEM)
break;
} else if (LF_ISSET(WT_READ_TRUNCATE)) {
/*
* Avoid pulling a deleted page back in to try
* to delete it again.
*/
if (ref->state == WT_REF_DELETED &&
__wt_delete_page_skip(session, ref))
break;
/*
* If deleting a range, try to delete the page
* without instantiating it.
*/
WT_ERR(__wt_delete_page(session, ref, &skip));
if (skip)
break;
} else if (LF_ISSET(WT_READ_COMPACT)) {
/*
* Skip deleted pages, rewriting them doesn't
* seem useful.
*/
if (ref->state == WT_REF_DELETED)
break;
/*
* If the page is in-memory, we want to look at
* it (it may have been modified and written,
* and the current location is the interesting
* one in terms of compaction, not the original
* location). If the page isn't in-memory, test
* if the page will help with compaction, don't
* read it if we don't have to.
*/
if (ref->state == WT_REF_DISK) {
WT_ERR(__wt_compact_page_skip(
session, ref, &skip));
if (skip)
break;
}
} else {
/*
* Try to skip deleted pages visible to us.
*/
if (ref->state == WT_REF_DELETED &&
__wt_delete_page_skip(session, ref))
break;
}
ret = __wt_page_swap(session, couple, ref, flags);
/*
* Not-found is an expected return when only walking
* in-cache pages.
*/
if (ret == WT_NOTFOUND) {
ret = 0;
break;
}
/*
* The page we're moving to might have split, in which
* case move to the last position we held.
*/
if (ret == WT_RESTART) {
ret = 0;
/*
* If a new walk that never coupled from the
* root to a new saved position in the tree,
* restart the walk.
*/
if (couple == &btree->root) {
ref = &btree->root;
if (ref->page == NULL)
goto done;
goto descend;
}
/*
* If restarting from some original position,
* repeat the increment or decrement we made at
* that time. Otherwise, couple is an internal
* page we've acquired after moving from that
* starting position and we can treat it as a
* new page. This works because we never acquire
* a hazard pointer on a leaf page we're not
* going to return to our caller, this will quit
* working if that ever changes.
*/
WT_ASSERT(session,
couple == couple_orig ||
WT_PAGE_IS_INTERNAL(couple->page));
ref = couple;
__wt_page_refp(session, ref, &pindex, &slot);
if (couple == couple_orig)
break;
}
WT_ERR(ret);
/*
* A new page: configure for traversal of any internal
* page's children, else return the leaf page.
*/
descend: couple = ref;
page = ref->page;
if (page->type == WT_PAGE_ROW_INT ||
page->type == WT_PAGE_COL_INT) {
WT_INTL_INDEX_GET(session, page, pindex);
slot = prev ? pindex->entries - 1 : 0;
} else {
*refp = ref;
goto done;
}
}
}
done:
err: WT_LEAVE_PAGE_INDEX(session);
return (ret);
}
/*
* editor --
* Main editor routine.
*
* PUBLIC: int editor __P((WIN *, int, char *[]));
*/
int
editor(WIN *wp, int argc, char **argv)
{
extern int optind;
extern char *optarg;
const char *p;
EVENT ev;
FREF *frp;
SCR *sp;
GS *gp;
size_t len;
u_int flags;
int ch, flagchk, lflag, secure, startup, readonly, rval, silent;
char *tag_f, *wsizearg, path[256];
CHAR_T *w;
size_t wlen;
gp = wp->gp;
/* Initialize the busy routine, if not defined by the screen. */
if (gp->scr_busy == NULL)
gp->scr_busy = vs_busy;
/* Initialize the message routine, if not defined by the screen. */
if (wp->scr_msg == NULL)
wp->scr_msg = vs_msg;
/* Set initial screen type and mode based on the program name. */
readonly = 0;
if (!strcmp(gp->progname, "ex") || !strcmp(gp->progname, "nex"))
LF_INIT(SC_EX);
else {
/* Nview, view are readonly. */
if (!strcmp(gp->progname, "nview") ||
!strcmp(gp->progname, "view"))
readonly = 1;
/* Vi is the default. */
LF_INIT(SC_VI);
}
/* Convert old-style arguments into new-style ones. */
if (v_obsolete(gp->progname, argv))
return (1);
/* Parse the arguments. */
flagchk = '\0';
tag_f = wsizearg = NULL;
lflag = secure = silent = 0;
startup = 1;
/* Set the file snapshot flag. */
F_SET(gp, G_SNAPSHOT);
#ifdef DEBUG
while ((ch = getopt(argc, argv, "c:D:eFlRrSsT:t:vw:")) != EOF)
#else
while ((ch = getopt(argc, argv, "c:eFlRrSst:vw:")) != EOF)
#endif
switch (ch) {
case 'c': /* Run the command. */
/*
* XXX
* We should support multiple -c options.
*/
if (gp->c_option != NULL) {
v_estr(gp->progname, 0,
"only one -c command may be specified.");
return (1);
}
gp->c_option = optarg;
break;
#ifdef DEBUG
case 'D':
switch (optarg[0]) {
case 's':
startup = 0;
break;
case 'w':
attach(gp);
break;
default:
v_estr(gp->progname, 0,
"usage: -D requires s or w argument.");
return (1);
}
break;
#endif
case 'e': /* Ex mode. */
LF_CLR(SC_VI);
LF_SET(SC_EX);
break;
case 'F': /* No snapshot. */
v_estr(gp->progname, 0,
"-F option no longer supported.");
break;
case 'l': /* Set lisp, showmatch options. */
lflag = 1;
break;
case 'R': /* Readonly. */
readonly = 1;
break;
case 'r': /* Recover. */
if (flagchk == 't') {
v_estr(gp->progname, 0,
"only one of -r and -t may be specified.");
return (1);
}
flagchk = 'r';
break;
case 'S':
secure = 1;
break;
case 's':
silent = 1;
break;
#ifdef TRACE
case 'T': /* Trace. */
(void)vtrace_init(optarg);
break;
#endif
case 't': /* Tag. */
if (flagchk == 'r') {
v_estr(gp->progname, 0,
"only one of -r and -t may be specified.");
return (1);
}
if (flagchk == 't') {
v_estr(gp->progname, 0,
"only one tag file may be specified.");
return (1);
}
flagchk = 't';
tag_f = optarg;
break;
case 'v': /* Vi mode. */
LF_CLR(SC_EX);
LF_SET(SC_VI);
break;
case 'w':
wsizearg = optarg;
break;
case '?':
default:
(void)gp->scr_usage();
return (1);
}
argc -= optind;
argv += optind;
/*
* -s option is only meaningful to ex.
*
* If not reading from a terminal, it's like -s was specified.
*/
if (silent && !LF_ISSET(SC_EX)) {
v_estr(gp->progname, 0, "-s option is only applicable to ex.");
goto err;
}
if (LF_ISSET(SC_EX) && F_ISSET(gp, G_SCRIPTED))
silent = 1;
/*
* Build and initialize the first/current screen. This is a bit
* tricky. If an error is returned, we may or may not have a
* screen structure. If we have a screen structure, put it on a
* display queue so that the error messages get displayed.
*
* !!!
* Everything we do until we go interactive is done in ex mode.
*/
if (screen_init(gp, NULL, &sp)) {
if (sp != NULL) {
CIRCLEQ_INSERT_HEAD(&wp->scrq, sp, q);
sp->wp = wp;
}
goto err;
}
F_SET(sp, SC_EX);
CIRCLEQ_INSERT_HEAD(&wp->scrq, sp, q);
sp->wp = wp;
if (v_key_init(sp)) /* Special key initialization. */
goto err;
{ int oargs[5], *oargp = oargs;
if (lflag) { /* Command-line options. */
*oargp++ = O_LISP;
*oargp++ = O_SHOWMATCH;
}
if (readonly)
*oargp++ = O_READONLY;
if (secure)
*oargp++ = O_SECURE;
*oargp = -1; /* Options initialization. */
if (opts_init(sp, oargs))
goto err;
}
if (wsizearg != NULL) {
ARGS *av[2], a, b;
(void)snprintf(path, sizeof(path), "window=%s", wsizearg);
a.bp = (CHAR_T *)path;
a.len = strlen(path);
b.bp = NULL;
b.len = 0;
av[0] = &a;
av[1] = &b;
(void)opts_set(sp, av, NULL);
}
if (silent) { /* Ex batch mode option values. */
O_CLR(sp, O_AUTOPRINT);
O_CLR(sp, O_PROMPT);
O_CLR(sp, O_VERBOSE);
O_CLR(sp, O_WARN);
F_SET(sp, SC_EX_SILENT);
}
sp->rows = O_VAL(sp, O_LINES); /* Make ex formatting work. */
sp->cols = O_VAL(sp, O_COLUMNS);
if (!silent && startup) { /* Read EXINIT, exrc files. */
if (ex_exrc(sp))
goto err;
if (F_ISSET(sp, SC_EXIT | SC_EXIT_FORCE)) {
if (screen_end(sp))
goto err;
goto done;
}
}
/*
* List recovery files if -r specified without file arguments.
* Note, options must be initialized and startup information
* read before doing this.
*/
if (flagchk == 'r' && argv[0] == NULL) {
if (rcv_list(sp))
goto err;
if (screen_end(sp))
goto err;
goto done;
}
/*
* !!!
* Initialize the default ^D, ^U scrolling value here, after the
* user has had every opportunity to set the window option.
*
* It's historic practice that changing the value of the window
* option did not alter the default scrolling value, only giving
* a count to ^D/^U did that.
*/
sp->defscroll = (O_VAL(sp, O_WINDOW) + 1) / 2;
/*
* If we don't have a command-line option, switch into the right
* editor now, so that we position default files correctly, and
* so that any tags file file-already-locked messages are in the
* vi screen, not the ex screen.
*
* XXX
* If we have a command-line option, the error message can end
* up in the wrong place, but I think that the combination is
* unlikely.
*/
if (gp->c_option == NULL) {
F_CLR(sp, SC_EX | SC_VI);
F_SET(sp, LF_ISSET(SC_EX | SC_VI));
}
/* Open a tag file if specified. */
if (tag_f != NULL) {
CHAR2INT(sp, tag_f, strlen(tag_f) + 1, w, wlen);
if (ex_tag_first(sp, w))
goto err;
}
/*
* Append any remaining arguments as file names. Files are recovery
* files if -r specified. If the tag option or ex startup commands
* loaded a file, then any file arguments are going to come after it.
*/
if (*argv != NULL) {
if (sp->frp != NULL) {
/* Cheat -- we know we have an extra argv slot. */
MALLOC_NOMSG(sp,
*--argv, char *, strlen(sp->frp->name) + 1);
if (*argv == NULL) {
v_estr(gp->progname, errno, NULL);
goto err;
}
(void)strcpy(*argv, sp->frp->name);
}
sp->argv = sp->cargv = argv;
F_SET(sp, SC_ARGNOFREE);
if (flagchk == 'r')
F_SET(sp, SC_ARGRECOVER);
}
/*
* v_motion --
*
* Get resulting motion mark.
*/
static int
v_motion(
SCR *sp,
VICMD *dm,
VICMD *vp,
int *mappedp)
{
VICMD motion;
size_t len;
u_long cnt;
u_int flags;
int tilde_reset, notused;
/*
* If '.' command, use the dot motion, else get the motion command.
* Clear any line motion flags, the subsequent motion isn't always
* the same, i.e. "/aaa" may or may not be a line motion.
*/
if (F_ISSET(vp, VC_ISDOT)) {
motion = *dm;
F_SET(&motion, VC_ISDOT);
F_CLR(&motion, VM_COMMASK);
} else {
memset(&motion, 0, sizeof(VICMD));
if (v_cmd(sp, NULL, &motion, vp, ¬used, mappedp) != GC_OK)
return (1);
}
/*
* A count may be provided both to the command and to the motion, in
* which case the count is multiplicative. For example, "3y4y" is the
* same as "12yy". This count is provided to the motion command and
* not to the regular function.
*/
cnt = motion.count = F_ISSET(&motion, VC_C1SET) ? motion.count : 1;
if (F_ISSET(vp, VC_C1SET)) {
motion.count *= vp->count;
F_SET(&motion, VC_C1SET);
/*
* Set flags to restore the original values of the command
* structure so dot commands can change the count values,
* e.g. "2dw" "3." deletes a total of five words.
*/
F_CLR(vp, VC_C1SET);
F_SET(vp, VC_C1RESET);
}
/*
* Some commands can be repeated to indicate the current line. In
* this case, or if the command is a "line command", set the flags
* appropriately. If not a doubled command, run the function to get
* the resulting mark.
*/
if (vp->key == motion.key) {
F_SET(vp, VM_LDOUBLE | VM_LMODE);
/* Set the origin of the command. */
vp->m_start.lno = sp->lno;
vp->m_start.cno = 0;
/*
* Set the end of the command.
*
* If the current line is missing, i.e. the file is empty,
* historic vi permitted a "cc" or "!!" command to insert
* text.
*/
vp->m_stop.lno = sp->lno + motion.count - 1;
if (db_get(sp, vp->m_stop.lno, 0, NULL, &len)) {
if (vp->m_stop.lno != 1 ||
(vp->key != 'c' && vp->key != '!')) {
v_emsg(sp, NULL, VIM_EMPTY);
return (1);
}
vp->m_stop.cno = 0;
} else
vp->m_stop.cno = len ? len - 1 : 0;
} else {
/*
* Motion commands change the underlying movement (*snarl*).
* For example, "l" is illegal at the end of a line, but "dl"
* is not. Set flags so the function knows the situation.
*/
motion.rkp = vp->kp;
/*
* XXX
* Use yank instead of creating a new motion command, it's a
* lot easier for now.
*/
if (vp->kp == &tmotion) {
tilde_reset = 1;
vp->kp = &vikeys['y'];
} else
tilde_reset = 0;
/*
* Copy the key flags into the local structure, except for the
* RCM flags -- the motion command will set the RCM flags in
* the vp structure if necessary. This means that the motion
* command is expected to determine where the cursor ends up!
* However, we save off the current RCM mask and restore it if
* it no RCM flags are set by the motion command, with a small
* modification.
*
* We replace the VM_RCM_SET flag with the VM_RCM flag. This
* is so that cursor movement doesn't set the relative position
* unless the motion command explicitly specified it. This
* appears to match historic practice, but I've never been able
* to develop a hard-and-fast rule.
*/
flags = F_ISSET(vp, VM_RCM_MASK);
if (LF_ISSET(VM_RCM_SET)) {
LF_SET(VM_RCM);
LF_CLR(VM_RCM_SET);
}
F_CLR(vp, VM_RCM_MASK);
F_SET(&motion, motion.kp->flags & ~VM_RCM_MASK);
/*
* Set the three cursor locations to the current cursor. This
* permits commands like 'j' and 'k', that are line oriented
* motions and have special cursor suck semantics when they are
* used as standalone commands, to ignore column positioning.
*/
motion.m_final.lno =
motion.m_stop.lno = motion.m_start.lno = sp->lno;
motion.m_final.cno =
motion.m_stop.cno = motion.m_start.cno = sp->cno;
/* Run the function. */
if ((motion.kp->func)(sp, &motion))
return (1);
/*
* If the current line is missing, i.e. the file is empty,
* historic vi allowed "c<motion>" or "!<motion>" to insert
* text. Otherwise fail -- most motion commands will have
* already failed, but some, e.g. G, succeed in empty files.
*/
if (!db_exist(sp, vp->m_stop.lno)) {
if (vp->m_stop.lno != 1 ||
(vp->key != 'c' && vp->key != '!')) {
v_emsg(sp, NULL, VIM_EMPTY);
return (1);
}
vp->m_stop.cno = 0;
}
/*
* XXX
* See above.
*/
if (tilde_reset)
vp->kp = &tmotion;
/*
* Copy cut buffer, line mode and cursor position information
* from the motion command structure, i.e. anything that the
* motion command can set for us. The commands can flag the
* movement as a line motion (see v_sentence) as well as set
* the VM_RCM_* flags explicitly.
*/
F_SET(vp, F_ISSET(&motion, VM_COMMASK | VM_RCM_MASK));
/*
* If the motion command set no relative motion flags, use
* the (slightly) modified previous values.
*/
if (!F_ISSET(vp, VM_RCM_MASK))
F_SET(vp, flags);
/*
* Commands can change behaviors based on the motion command
* used, for example, the ! command repeated the last bang
* command if N or n was used as the motion.
*/
vp->rkp = motion.kp;
/*
* Motion commands can reset all of the cursor information.
* If the motion is in the reverse direction, switch the
* from and to MARK's so that it's in a forward direction.
* Motions are from the from MARK to the to MARK (inclusive).
*/
if (motion.m_start.lno > motion.m_stop.lno ||
(motion.m_start.lno == motion.m_stop.lno &&
motion.m_start.cno > motion.m_stop.cno)) {
vp->m_start = motion.m_stop;
vp->m_stop = motion.m_start;
} else {
vp->m_start = motion.m_start;
vp->m_stop = motion.m_stop;
}
vp->m_final = motion.m_final;
}
/*
* If the command sets dot, save the motion structure. The motion
* count was changed above and needs to be reset, that's why this
* is done here, and not in the calling routine.
*/
if (F_ISSET(vp->kp, V_DOT)) {
*dm = motion;
dm->count = cnt;
}
return (0);
}
/*
* __tree_walk_internal --
* Move to the next/previous page in the tree.
*/
static inline int
__tree_walk_internal(WT_SESSION_IMPL *session,
WT_REF **refp, uint64_t *walkcntp, uint64_t *skipleafcntp, uint32_t flags)
{
WT_BTREE *btree;
WT_DECL_RET;
WT_PAGE_INDEX *pindex;
WT_REF *couple, *couple_orig, *ref;
bool empty_internal, prev, skip;
uint32_t slot;
btree = S2BT(session);
empty_internal = false;
/*
* Tree walks are special: they look inside page structures that splits
* may want to free. Publish that the tree is active during this
* window.
*/
WT_ENTER_PAGE_INDEX(session);
/* Walk should never instantiate deleted pages. */
LF_SET(WT_READ_NO_EMPTY);
/*
* !!!
* Fast-truncate currently only works on row-store trees.
*/
if (btree->type != BTREE_ROW)
LF_CLR(WT_READ_TRUNCATE);
prev = LF_ISSET(WT_READ_PREV) ? 1 : 0;
/*
* There are multiple reasons and approaches to walking the in-memory
* tree:
*
* (1) finding pages to evict (the eviction server);
* (2) writing just dirty leaves or internal nodes (checkpoint);
* (3) discarding pages (close);
* (4) truncating pages in a range (fast truncate);
* (5) skipping pages based on outside information (compaction);
* (6) cursor scans (applications).
*
* Except for cursor scans and compaction, the walk is limited to the
* cache, no pages are read. In all cases, hazard pointers protect the
* walked pages from eviction.
*
* Walks use hazard-pointer coupling through the tree and that's OK
* (hazard pointers can't deadlock, so there's none of the usual
* problems found when logically locking up a btree). If the eviction
* thread tries to evict the active page, it fails because of our
* hazard pointer. If eviction tries to evict our parent, that fails
* because the parent has a child page that can't be discarded. We do
* play one game: don't couple up to our parent and then back down to a
* new leaf, couple to the next page to which we're descending, it
* saves a hazard-pointer swap for each cursor page movement.
*
* !!!
* NOTE: we depend on the fact it's OK to release a page we don't hold,
* that is, it's OK to release couple when couple is set to NULL.
*
* Take a copy of any held page and clear the return value. Remember
* the hazard pointer we're currently holding.
*
* We may be passed a pointer to btree->evict_page that we are clearing
* here. We check when discarding pages that we're not discarding that
* page, so this clear must be done before the page is released.
*/
couple = couple_orig = ref = *refp;
*refp = NULL;
/* If no page is active, begin a walk from the start of the tree. */
if (ref == NULL) {
ref = &btree->root;
if (ref->page == NULL)
goto done;
goto descend;
}
/*
* If the active page was the root, we've reached the walk's end.
* Release any hazard-pointer we're holding.
*/
if (__wt_ref_is_root(ref)) {
WT_ERR(__wt_page_release(session, couple, flags));
goto done;
}
/* Figure out the current slot in the WT_REF array. */
__ref_index_slot(session, ref, &pindex, &slot);
for (;;) {
/*
* If we're at the last/first slot on the internal page, return
* it in post-order traversal. Otherwise move to the next/prev
* slot and left/right-most element in that subtree.
*/
while ((prev && slot == 0) ||
(!prev && slot == pindex->entries - 1)) {
/* Ascend to the parent. */
__page_ascend(session, &ref, &pindex, &slot);
/*
* If we got all the way through an internal page and
* all of the child pages were deleted, mark it for
* eviction.
*/
if (empty_internal && pindex->entries > 1) {
__wt_page_evict_soon(ref->page);
empty_internal = false;
}
/*
* If at the root and returning internal pages, return
* the root page, otherwise we're done. Regardless, no
* hazard pointer is required, release the one we hold.
*/
if (__wt_ref_is_root(ref)) {
WT_ERR(__wt_page_release(
session, couple, flags));
if (!LF_ISSET(WT_READ_SKIP_INTL))
*refp = ref;
goto done;
}
/*
* Optionally return internal pages. Swap our previous
* hazard pointer for the page we'll return. We don't
* handle restart or not-found returns, it would require
* additional complexity and is not a possible return:
* we're moving to the parent of the current child page,
* the parent can't have been evicted.
*/
if (!LF_ISSET(WT_READ_SKIP_INTL)) {
WT_ERR(__wt_page_swap(
session, couple, ref, flags));
*refp = ref;
goto done;
}
}
if (prev)
--slot;
else
++slot;
if (walkcntp != NULL)
++*walkcntp;
for (;;) {
/*
* Move to the next slot, and set the reference hint if
* it's wrong (used when we continue the walk). We don't
* update those hints when splitting, so it's common for
* them to be incorrect in some workloads.
*/
ref = pindex->index[slot];
if (ref->pindex_hint != slot)
ref->pindex_hint = slot;
/*
* If we see any child states other than deleted, the
* page isn't empty.
*/
if (ref->state != WT_REF_DELETED &&
!LF_ISSET(WT_READ_TRUNCATE))
empty_internal = false;
if (LF_ISSET(WT_READ_CACHE)) {
/*
* Only look at unlocked pages in memory:
* fast-path some common cases.
*/
if (LF_ISSET(WT_READ_NO_WAIT) &&
ref->state != WT_REF_MEM)
break;
} else if (LF_ISSET(WT_READ_TRUNCATE)) {
/*
* Avoid pulling a deleted page back in to try
* to delete it again.
*/
if (ref->state == WT_REF_DELETED &&
__wt_delete_page_skip(session, ref, false))
break;
/*
* If deleting a range, try to delete the page
* without instantiating it.
*/
WT_ERR(__wt_delete_page(session, ref, &skip));
if (skip)
break;
empty_internal = false;
} else if (LF_ISSET(WT_READ_COMPACT)) {
/*
* Skip deleted pages, rewriting them doesn't
* seem useful.
*/
if (ref->state == WT_REF_DELETED)
break;
/*
* If the page is in-memory, we want to look at
* it (it may have been modified and written,
* and the current location is the interesting
* one in terms of compaction, not the original
* location). If the page isn't in-memory, test
* if the page will help with compaction, don't
* read it if we don't have to.
*/
if (ref->state == WT_REF_DISK) {
WT_ERR(__wt_compact_page_skip(
session, ref, &skip));
if (skip)
break;
}
} else {
/*
* Try to skip deleted pages visible to us.
*/
if (ref->state == WT_REF_DELETED &&
__wt_delete_page_skip(session, ref, false))
break;
}
/*
* Optionally skip leaf pages: skip all leaf pages if
* WT_READ_SKIP_LEAF is set, when the skip-leaf-count
* variable is non-zero, skip some count of leaf pages.
* If this page is disk-based, crack the cell to figure
* out it's a leaf page without reading it.
*
* If skipping some number of leaf pages, decrement the
* count of pages to zero, and then take the next leaf
* page we can. Be cautious around the page decrement,
* if for some reason don't take this particular page,
* we can take the next one, and, there are additional
* tests/decrements when we're about to return a leaf
* page.
*/
if (skipleafcntp != NULL || LF_ISSET(WT_READ_SKIP_LEAF))
if (__ref_is_leaf(ref)) {
if (LF_ISSET(WT_READ_SKIP_LEAF))
break;
if (*skipleafcntp > 0) {
--*skipleafcntp;
break;
}
}
ret = __wt_page_swap(session, couple, ref,
WT_READ_NOTFOUND_OK | WT_READ_RESTART_OK | flags);
/*
* Not-found is an expected return when only walking
* in-cache pages, or if we see a deleted page.
*/
if (ret == WT_NOTFOUND) {
ret = 0;
break;
}
/*
* The page we're moving to might have split, in which
* case move to the last position we held.
*/
if (ret == WT_RESTART) {
ret = 0;
/*
* If a new walk that never coupled from the
* root to a new saved position in the tree,
* restart the walk.
*/
if (couple == &btree->root) {
ref = &btree->root;
if (ref->page == NULL)
goto done;
goto descend;
}
/*
* If restarting from some original position,
* repeat the increment or decrement we made at
* that time. Otherwise, couple is an internal
* page we've acquired after moving from that
* starting position and we can treat it as a
* new page. This works because we never acquire
* a hazard pointer on a leaf page we're not
* going to return to our caller, this will quit
* working if that ever changes.
*/
WT_ASSERT(session,
couple == couple_orig ||
WT_PAGE_IS_INTERNAL(couple->page));
ref = couple;
__ref_index_slot(session, ref, &pindex, &slot);
if (couple == couple_orig)
break;
}
WT_ERR(ret);
/*
* A new page: configure for traversal of any internal
* page's children, else return the leaf page.
*/
if (WT_PAGE_IS_INTERNAL(ref->page)) {
descend: couple = ref;
empty_internal = true;
__page_descend(
session, ref->page, &pindex, &slot, prev);
} else {
/*
* Optionally skip leaf pages, the second half.
* We didn't have an on-page cell to figure out
* if it was a leaf page, we had to acquire the
* hazard pointer and look at the page.
*/
if (skipleafcntp != NULL ||
LF_ISSET(WT_READ_SKIP_LEAF)) {
couple = ref;
if (LF_ISSET(WT_READ_SKIP_LEAF))
break;
if (*skipleafcntp > 0) {
--*skipleafcntp;
break;
}
}
*refp = ref;
goto done;
}
}
}
done:
err: WT_LEAVE_PAGE_INDEX(session);
return (ret);
}
