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undo.c
3579 lines (3255 loc) · 88.4 KB
/
undo.c
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/* vi:set ts=8 sts=4 sw=4 noet:
*
* VIM - Vi IMproved by Bram Moolenaar
*
* Do ":help uganda" in Vim to read copying and usage conditions.
* Do ":help credits" in Vim to see a list of people who contributed.
* See README.txt for an overview of the Vim source code.
*/
/*
* undo.c: multi level undo facility
*
* The saved lines are stored in a list of lists (one for each buffer):
*
* b_u_oldhead------------------------------------------------+
* |
* V
* +--------------+ +--------------+ +--------------+
* b_u_newhead--->| u_header | | u_header | | u_header |
* | uh_next------>| uh_next------>| uh_next---->NULL
* NULL<--------uh_prev |<---------uh_prev |<---------uh_prev |
* | uh_entry | | uh_entry | | uh_entry |
* +--------|-----+ +--------|-----+ +--------|-----+
* | | |
* V V V
* +--------------+ +--------------+ +--------------+
* | u_entry | | u_entry | | u_entry |
* | ue_next | | ue_next | | ue_next |
* +--------|-----+ +--------|-----+ +--------|-----+
* | | |
* V V V
* +--------------+ NULL NULL
* | u_entry |
* | ue_next |
* +--------|-----+
* |
* V
* etc.
*
* Each u_entry list contains the information for one undo or redo.
* curbuf->b_u_curhead points to the header of the last undo (the next redo),
* or is NULL if nothing has been undone (end of the branch).
*
* For keeping alternate undo/redo branches the uh_alt field is used. Thus at
* each point in the list a branch may appear for an alternate to redo. The
* uh_seq field is numbered sequentially to be able to find a newer or older
* branch.
*
* +---------------+ +---------------+
* b_u_oldhead --->| u_header | | u_header |
* | uh_alt_next ---->| uh_alt_next ----> NULL
* NULL <----- uh_alt_prev |<------ uh_alt_prev |
* | uh_prev | | uh_prev |
* +-----|---------+ +-----|---------+
* | |
* V V
* +---------------+ +---------------+
* | u_header | | u_header |
* | uh_alt_next | | uh_alt_next |
* b_u_newhead --->| uh_alt_prev | | uh_alt_prev |
* | uh_prev | | uh_prev |
* +-----|---------+ +-----|---------+
* | |
* V V
* NULL +---------------+ +---------------+
* | u_header | | u_header |
* | uh_alt_next ---->| uh_alt_next |
* | uh_alt_prev |<------ uh_alt_prev |
* | uh_prev | | uh_prev |
* +-----|---------+ +-----|---------+
* | |
* etc. etc.
*
*
* All data is allocated and will all be freed when the buffer is unloaded.
*/
/* Uncomment the next line for including the u_check() function. This warns
* for errors in the debug information. */
/* #define U_DEBUG 1 */
#define UH_MAGIC 0x18dade /* value for uh_magic when in use */
#define UE_MAGIC 0xabc123 /* value for ue_magic when in use */
/* Size of buffer used for encryption. */
#define CRYPT_BUF_SIZE 8192
#include "vim.h"
/* Structure passed around between functions.
* Avoids passing cryptstate_T when encryption not available. */
typedef struct {
buf_T *bi_buf;
FILE *bi_fp;
#ifdef FEAT_CRYPT
cryptstate_T *bi_state;
char_u *bi_buffer; /* CRYPT_BUF_SIZE, NULL when not buffering */
size_t bi_used; /* bytes written to/read from bi_buffer */
size_t bi_avail; /* bytes available in bi_buffer */
#endif
} bufinfo_T;
static long get_undolevel(void);
static void u_unch_branch(u_header_T *uhp);
static u_entry_T *u_get_headentry(void);
static void u_getbot(void);
static void u_doit(int count);
static void u_undoredo(int undo);
static void u_undo_end(int did_undo, int absolute);
static void u_add_time(char_u *buf, size_t buflen, time_t tt);
static void u_freeheader(buf_T *buf, u_header_T *uhp, u_header_T **uhpp);
static void u_freebranch(buf_T *buf, u_header_T *uhp, u_header_T **uhpp);
static void u_freeentries(buf_T *buf, u_header_T *uhp, u_header_T **uhpp);
static void u_freeentry(u_entry_T *, long);
#ifdef FEAT_PERSISTENT_UNDO
static void corruption_error(char *mesg, char_u *file_name);
static void u_free_uhp(u_header_T *uhp);
static int undo_write(bufinfo_T *bi, char_u *ptr, size_t len);
# ifdef FEAT_CRYPT
static int undo_flush(bufinfo_T *bi);
# endif
static int fwrite_crypt(bufinfo_T *bi, char_u *ptr, size_t len);
static int undo_write_bytes(bufinfo_T *bi, long_u nr, int len);
static void put_header_ptr(bufinfo_T *bi, u_header_T *uhp);
static int undo_read_4c(bufinfo_T *bi);
static int undo_read_2c(bufinfo_T *bi);
static int undo_read_byte(bufinfo_T *bi);
static time_t undo_read_time(bufinfo_T *bi);
static int undo_read(bufinfo_T *bi, char_u *buffer, size_t size);
static char_u *read_string_decrypt(bufinfo_T *bi, int len);
static int serialize_header(bufinfo_T *bi, char_u *hash);
static int serialize_uhp(bufinfo_T *bi, u_header_T *uhp);
static u_header_T *unserialize_uhp(bufinfo_T *bi, char_u *file_name);
static int serialize_uep(bufinfo_T *bi, u_entry_T *uep);
static u_entry_T *unserialize_uep(bufinfo_T *bi, int *error, char_u *file_name);
static void serialize_pos(bufinfo_T *bi, pos_T pos);
static void unserialize_pos(bufinfo_T *bi, pos_T *pos);
static void serialize_visualinfo(bufinfo_T *bi, visualinfo_T *info);
static void unserialize_visualinfo(bufinfo_T *bi, visualinfo_T *info);
#endif
#define U_ALLOC_LINE(size) lalloc((long_u)(size), FALSE)
static char_u *u_save_line(linenr_T);
/* used in undo_end() to report number of added and deleted lines */
static long u_newcount, u_oldcount;
/*
* When 'u' flag included in 'cpoptions', we behave like vi. Need to remember
* the action that "u" should do.
*/
static int undo_undoes = FALSE;
static int lastmark = 0;
#if defined(U_DEBUG) || defined(PROTO)
/*
* Check the undo structures for being valid. Print a warning when something
* looks wrong.
*/
static int seen_b_u_curhead;
static int seen_b_u_newhead;
static int header_count;
static void
u_check_tree(u_header_T *uhp,
u_header_T *exp_uh_next,
u_header_T *exp_uh_alt_prev)
{
u_entry_T *uep;
if (uhp == NULL)
return;
++header_count;
if (uhp == curbuf->b_u_curhead && ++seen_b_u_curhead > 1)
{
EMSG("b_u_curhead found twice (looping?)");
return;
}
if (uhp == curbuf->b_u_newhead && ++seen_b_u_newhead > 1)
{
EMSG("b_u_newhead found twice (looping?)");
return;
}
if (uhp->uh_magic != UH_MAGIC)
EMSG("uh_magic wrong (may be using freed memory)");
else
{
/* Check pointers back are correct. */
if (uhp->uh_next.ptr != exp_uh_next)
{
EMSG("uh_next wrong");
smsg((char_u *)"expected: 0x%x, actual: 0x%x",
exp_uh_next, uhp->uh_next.ptr);
}
if (uhp->uh_alt_prev.ptr != exp_uh_alt_prev)
{
EMSG("uh_alt_prev wrong");
smsg((char_u *)"expected: 0x%x, actual: 0x%x",
exp_uh_alt_prev, uhp->uh_alt_prev.ptr);
}
/* Check the undo tree at this header. */
for (uep = uhp->uh_entry; uep != NULL; uep = uep->ue_next)
{
if (uep->ue_magic != UE_MAGIC)
{
EMSG("ue_magic wrong (may be using freed memory)");
break;
}
}
/* Check the next alt tree. */
u_check_tree(uhp->uh_alt_next.ptr, uhp->uh_next.ptr, uhp);
/* Check the next header in this branch. */
u_check_tree(uhp->uh_prev.ptr, uhp, NULL);
}
}
static void
u_check(int newhead_may_be_NULL)
{
seen_b_u_newhead = 0;
seen_b_u_curhead = 0;
header_count = 0;
u_check_tree(curbuf->b_u_oldhead, NULL, NULL);
if (seen_b_u_newhead == 0 && curbuf->b_u_oldhead != NULL
&& !(newhead_may_be_NULL && curbuf->b_u_newhead == NULL))
EMSGN("b_u_newhead invalid: 0x%x", curbuf->b_u_newhead);
if (curbuf->b_u_curhead != NULL && seen_b_u_curhead == 0)
EMSGN("b_u_curhead invalid: 0x%x", curbuf->b_u_curhead);
if (header_count != curbuf->b_u_numhead)
{
EMSG("b_u_numhead invalid");
smsg((char_u *)"expected: %ld, actual: %ld",
(long)header_count, (long)curbuf->b_u_numhead);
}
}
#endif
/*
* Save the current line for both the "u" and "U" command.
* Careful: may trigger autocommands that reload the buffer.
* Returns OK or FAIL.
*/
int
u_save_cursor(void)
{
return (u_save((linenr_T)(curwin->w_cursor.lnum - 1),
(linenr_T)(curwin->w_cursor.lnum + 1)));
}
/*
* Save the lines between "top" and "bot" for both the "u" and "U" command.
* "top" may be 0 and bot may be curbuf->b_ml.ml_line_count + 1.
* Careful: may trigger autocommands that reload the buffer.
* Returns FAIL when lines could not be saved, OK otherwise.
*/
int
u_save(linenr_T top, linenr_T bot)
{
if (undo_off)
return OK;
if (top > curbuf->b_ml.ml_line_count
|| top >= bot
|| bot > curbuf->b_ml.ml_line_count + 1)
return FALSE; /* rely on caller to do error messages */
if (top + 2 == bot)
u_saveline((linenr_T)(top + 1));
return (u_savecommon(top, bot, (linenr_T)0, FALSE));
}
/*
* Save the line "lnum" (used by ":s" and "~" command).
* The line is replaced, so the new bottom line is lnum + 1.
* Careful: may trigger autocommands that reload the buffer.
* Returns FAIL when lines could not be saved, OK otherwise.
*/
int
u_savesub(linenr_T lnum)
{
if (undo_off)
return OK;
return (u_savecommon(lnum - 1, lnum + 1, lnum + 1, FALSE));
}
/*
* A new line is inserted before line "lnum" (used by :s command).
* The line is inserted, so the new bottom line is lnum + 1.
* Careful: may trigger autocommands that reload the buffer.
* Returns FAIL when lines could not be saved, OK otherwise.
*/
int
u_inssub(linenr_T lnum)
{
if (undo_off)
return OK;
return (u_savecommon(lnum - 1, lnum, lnum + 1, FALSE));
}
/*
* Save the lines "lnum" - "lnum" + nlines (used by delete command).
* The lines are deleted, so the new bottom line is lnum, unless the buffer
* becomes empty.
* Careful: may trigger autocommands that reload the buffer.
* Returns FAIL when lines could not be saved, OK otherwise.
*/
int
u_savedel(linenr_T lnum, long nlines)
{
if (undo_off)
return OK;
return (u_savecommon(lnum - 1, lnum + nlines,
nlines == curbuf->b_ml.ml_line_count ? 2 : lnum, FALSE));
}
/*
* Return TRUE when undo is allowed. Otherwise give an error message and
* return FALSE.
*/
int
undo_allowed(void)
{
/* Don't allow changes when 'modifiable' is off. */
if (!curbuf->b_p_ma)
{
EMSG(_(e_modifiable));
return FALSE;
}
#ifdef HAVE_SANDBOX
/* In the sandbox it's not allowed to change the text. */
if (sandbox != 0)
{
EMSG(_(e_sandbox));
return FALSE;
}
#endif
/* Don't allow changes in the buffer while editing the cmdline. The
* caller of getcmdline() may get confused. */
if (textlock != 0)
{
EMSG(_(e_secure));
return FALSE;
}
return TRUE;
}
/*
* Get the undolevle value for the current buffer.
*/
static long
get_undolevel(void)
{
if (curbuf->b_p_ul == NO_LOCAL_UNDOLEVEL)
return p_ul;
return curbuf->b_p_ul;
}
/*
* Common code for various ways to save text before a change.
* "top" is the line above the first changed line.
* "bot" is the line below the last changed line.
* "newbot" is the new bottom line. Use zero when not known.
* "reload" is TRUE when saving for a buffer reload.
* Careful: may trigger autocommands that reload the buffer.
* Returns FAIL when lines could not be saved, OK otherwise.
*/
int
u_savecommon(
linenr_T top,
linenr_T bot,
linenr_T newbot,
int reload)
{
linenr_T lnum;
long i;
u_header_T *uhp;
u_header_T *old_curhead;
u_entry_T *uep;
u_entry_T *prev_uep;
long size;
if (!reload)
{
/* When making changes is not allowed return FAIL. It's a crude way
* to make all change commands fail. */
if (!undo_allowed())
return FAIL;
#ifdef FEAT_NETBEANS_INTG
/*
* Netbeans defines areas that cannot be modified. Bail out here when
* trying to change text in a guarded area.
*/
if (netbeans_active())
{
if (netbeans_is_guarded(top, bot))
{
EMSG(_(e_guarded));
return FAIL;
}
if (curbuf->b_p_ro)
{
EMSG(_(e_nbreadonly));
return FAIL;
}
}
#endif
#ifdef FEAT_AUTOCMD
/*
* Saving text for undo means we are going to make a change. Give a
* warning for a read-only file before making the change, so that the
* FileChangedRO event can replace the buffer with a read-write version
* (e.g., obtained from a source control system).
*/
change_warning(0);
if (bot > curbuf->b_ml.ml_line_count + 1)
{
/* This happens when the FileChangedRO autocommand changes the
* file in a way it becomes shorter. */
EMSG(_("E881: Line count changed unexpectedly"));
return FAIL;
}
#endif
}
#ifdef U_DEBUG
u_check(FALSE);
#endif
size = bot - top - 1;
/*
* If curbuf->b_u_synced == TRUE make a new header.
*/
if (curbuf->b_u_synced)
{
#ifdef FEAT_JUMPLIST
/* Need to create new entry in b_changelist. */
curbuf->b_new_change = TRUE;
#endif
if (get_undolevel() >= 0)
{
/*
* Make a new header entry. Do this first so that we don't mess
* up the undo info when out of memory.
*/
uhp = (u_header_T *)U_ALLOC_LINE(sizeof(u_header_T));
if (uhp == NULL)
goto nomem;
#ifdef U_DEBUG
uhp->uh_magic = UH_MAGIC;
#endif
}
else
uhp = NULL;
/*
* If we undid more than we redid, move the entry lists before and
* including curbuf->b_u_curhead to an alternate branch.
*/
old_curhead = curbuf->b_u_curhead;
if (old_curhead != NULL)
{
curbuf->b_u_newhead = old_curhead->uh_next.ptr;
curbuf->b_u_curhead = NULL;
}
/*
* free headers to keep the size right
*/
while (curbuf->b_u_numhead > get_undolevel()
&& curbuf->b_u_oldhead != NULL)
{
u_header_T *uhfree = curbuf->b_u_oldhead;
if (uhfree == old_curhead)
/* Can't reconnect the branch, delete all of it. */
u_freebranch(curbuf, uhfree, &old_curhead);
else if (uhfree->uh_alt_next.ptr == NULL)
/* There is no branch, only free one header. */
u_freeheader(curbuf, uhfree, &old_curhead);
else
{
/* Free the oldest alternate branch as a whole. */
while (uhfree->uh_alt_next.ptr != NULL)
uhfree = uhfree->uh_alt_next.ptr;
u_freebranch(curbuf, uhfree, &old_curhead);
}
#ifdef U_DEBUG
u_check(TRUE);
#endif
}
if (uhp == NULL) /* no undo at all */
{
if (old_curhead != NULL)
u_freebranch(curbuf, old_curhead, NULL);
curbuf->b_u_synced = FALSE;
return OK;
}
uhp->uh_prev.ptr = NULL;
uhp->uh_next.ptr = curbuf->b_u_newhead;
uhp->uh_alt_next.ptr = old_curhead;
if (old_curhead != NULL)
{
uhp->uh_alt_prev.ptr = old_curhead->uh_alt_prev.ptr;
if (uhp->uh_alt_prev.ptr != NULL)
uhp->uh_alt_prev.ptr->uh_alt_next.ptr = uhp;
old_curhead->uh_alt_prev.ptr = uhp;
if (curbuf->b_u_oldhead == old_curhead)
curbuf->b_u_oldhead = uhp;
}
else
uhp->uh_alt_prev.ptr = NULL;
if (curbuf->b_u_newhead != NULL)
curbuf->b_u_newhead->uh_prev.ptr = uhp;
uhp->uh_seq = ++curbuf->b_u_seq_last;
curbuf->b_u_seq_cur = uhp->uh_seq;
uhp->uh_time = vim_time();
uhp->uh_save_nr = 0;
curbuf->b_u_time_cur = uhp->uh_time + 1;
uhp->uh_walk = 0;
uhp->uh_entry = NULL;
uhp->uh_getbot_entry = NULL;
uhp->uh_cursor = curwin->w_cursor; /* save cursor pos. for undo */
#ifdef FEAT_VIRTUALEDIT
if (virtual_active() && curwin->w_cursor.coladd > 0)
uhp->uh_cursor_vcol = getviscol();
else
uhp->uh_cursor_vcol = -1;
#endif
/* save changed and buffer empty flag for undo */
uhp->uh_flags = (curbuf->b_changed ? UH_CHANGED : 0) +
((curbuf->b_ml.ml_flags & ML_EMPTY) ? UH_EMPTYBUF : 0);
/* save named marks and Visual marks for undo */
mch_memmove(uhp->uh_namedm, curbuf->b_namedm, sizeof(pos_T) * NMARKS);
uhp->uh_visual = curbuf->b_visual;
curbuf->b_u_newhead = uhp;
if (curbuf->b_u_oldhead == NULL)
curbuf->b_u_oldhead = uhp;
++curbuf->b_u_numhead;
}
else
{
if (get_undolevel() < 0) /* no undo at all */
return OK;
/*
* When saving a single line, and it has been saved just before, it
* doesn't make sense saving it again. Saves a lot of memory when
* making lots of changes inside the same line.
* This is only possible if the previous change didn't increase or
* decrease the number of lines.
* Check the ten last changes. More doesn't make sense and takes too
* long.
*/
if (size == 1)
{
uep = u_get_headentry();
prev_uep = NULL;
for (i = 0; i < 10; ++i)
{
if (uep == NULL)
break;
/* If lines have been inserted/deleted we give up.
* Also when the line was included in a multi-line save. */
if ((curbuf->b_u_newhead->uh_getbot_entry != uep
? (uep->ue_top + uep->ue_size + 1
!= (uep->ue_bot == 0
? curbuf->b_ml.ml_line_count + 1
: uep->ue_bot))
: uep->ue_lcount != curbuf->b_ml.ml_line_count)
|| (uep->ue_size > 1
&& top >= uep->ue_top
&& top + 2 <= uep->ue_top + uep->ue_size + 1))
break;
/* If it's the same line we can skip saving it again. */
if (uep->ue_size == 1 && uep->ue_top == top)
{
if (i > 0)
{
/* It's not the last entry: get ue_bot for the last
* entry now. Following deleted/inserted lines go to
* the re-used entry. */
u_getbot();
curbuf->b_u_synced = FALSE;
/* Move the found entry to become the last entry. The
* order of undo/redo doesn't matter for the entries
* we move it over, since they don't change the line
* count and don't include this line. It does matter
* for the found entry if the line count is changed by
* the executed command. */
prev_uep->ue_next = uep->ue_next;
uep->ue_next = curbuf->b_u_newhead->uh_entry;
curbuf->b_u_newhead->uh_entry = uep;
}
/* The executed command may change the line count. */
if (newbot != 0)
uep->ue_bot = newbot;
else if (bot > curbuf->b_ml.ml_line_count)
uep->ue_bot = 0;
else
{
uep->ue_lcount = curbuf->b_ml.ml_line_count;
curbuf->b_u_newhead->uh_getbot_entry = uep;
}
return OK;
}
prev_uep = uep;
uep = uep->ue_next;
}
}
/* find line number for ue_bot for previous u_save() */
u_getbot();
}
#if !defined(UNIX) && !defined(WIN32)
/*
* With Amiga we can't handle big undo's, because
* then u_alloc_line would have to allocate a block larger than 32K
*/
if (size >= 8000)
goto nomem;
#endif
/*
* add lines in front of entry list
*/
uep = (u_entry_T *)U_ALLOC_LINE(sizeof(u_entry_T));
if (uep == NULL)
goto nomem;
vim_memset(uep, 0, sizeof(u_entry_T));
#ifdef U_DEBUG
uep->ue_magic = UE_MAGIC;
#endif
uep->ue_size = size;
uep->ue_top = top;
if (newbot != 0)
uep->ue_bot = newbot;
/*
* Use 0 for ue_bot if bot is below last line.
* Otherwise we have to compute ue_bot later.
*/
else if (bot > curbuf->b_ml.ml_line_count)
uep->ue_bot = 0;
else
{
uep->ue_lcount = curbuf->b_ml.ml_line_count;
curbuf->b_u_newhead->uh_getbot_entry = uep;
}
if (size > 0)
{
if ((uep->ue_array = (char_u **)U_ALLOC_LINE(
sizeof(char_u *) * size)) == NULL)
{
u_freeentry(uep, 0L);
goto nomem;
}
for (i = 0, lnum = top + 1; i < size; ++i)
{
fast_breakcheck();
if (got_int)
{
u_freeentry(uep, i);
return FAIL;
}
if ((uep->ue_array[i] = u_save_line(lnum++)) == NULL)
{
u_freeentry(uep, i);
goto nomem;
}
}
}
else
uep->ue_array = NULL;
uep->ue_next = curbuf->b_u_newhead->uh_entry;
curbuf->b_u_newhead->uh_entry = uep;
curbuf->b_u_synced = FALSE;
undo_undoes = FALSE;
#ifdef U_DEBUG
u_check(FALSE);
#endif
return OK;
nomem:
msg_silent = 0; /* must display the prompt */
if (ask_yesno((char_u *)_("No undo possible; continue anyway"), TRUE)
== 'y')
{
undo_off = TRUE; /* will be reset when character typed */
return OK;
}
do_outofmem_msg((long_u)0);
return FAIL;
}
#if defined(FEAT_PERSISTENT_UNDO) || defined(PROTO)
# define UF_START_MAGIC "Vim\237UnDo\345" /* magic at start of undofile */
# define UF_START_MAGIC_LEN 9
# define UF_HEADER_MAGIC 0x5fd0 /* magic at start of header */
# define UF_HEADER_END_MAGIC 0xe7aa /* magic after last header */
# define UF_ENTRY_MAGIC 0xf518 /* magic at start of entry */
# define UF_ENTRY_END_MAGIC 0x3581 /* magic after last entry */
# define UF_VERSION 2 /* 2-byte undofile version number */
# define UF_VERSION_CRYPT 0x8002 /* idem, encrypted */
/* extra fields for header */
# define UF_LAST_SAVE_NR 1
/* extra fields for uhp */
# define UHP_SAVE_NR 1
static char_u e_not_open[] = N_("E828: Cannot open undo file for writing: %s");
/*
* Compute the hash for the current buffer text into hash[UNDO_HASH_SIZE].
*/
void
u_compute_hash(char_u *hash)
{
context_sha256_T ctx;
linenr_T lnum;
char_u *p;
sha256_start(&ctx);
for (lnum = 1; lnum <= curbuf->b_ml.ml_line_count; ++lnum)
{
p = ml_get(lnum);
sha256_update(&ctx, p, (UINT32_T)(STRLEN(p) + 1));
}
sha256_finish(&ctx, hash);
}
/*
* Return an allocated string of the full path of the target undofile.
* When "reading" is TRUE find the file to read, go over all directories in
* 'undodir'.
* When "reading" is FALSE use the first name where the directory exists.
* Returns NULL when there is no place to write or no file to read.
*/
char_u *
u_get_undo_file_name(char_u *buf_ffname, int reading)
{
char_u *dirp;
char_u dir_name[IOSIZE + 1];
char_u *munged_name = NULL;
char_u *undo_file_name = NULL;
int dir_len;
char_u *p;
stat_T st;
char_u *ffname = buf_ffname;
#ifdef HAVE_READLINK
char_u fname_buf[MAXPATHL];
#endif
if (ffname == NULL)
return NULL;
#ifdef HAVE_READLINK
/* Expand symlink in the file name, so that we put the undo file with the
* actual file instead of with the symlink. */
if (resolve_symlink(ffname, fname_buf) == OK)
ffname = fname_buf;
#endif
/* Loop over 'undodir'. When reading find the first file that exists.
* When not reading use the first directory that exists or ".". */
dirp = p_udir;
while (*dirp != NUL)
{
dir_len = copy_option_part(&dirp, dir_name, IOSIZE, ",");
if (dir_len == 1 && dir_name[0] == '.')
{
/* Use same directory as the ffname,
* "dir/name" -> "dir/.name.un~" */
undo_file_name = vim_strnsave(ffname, (int)(STRLEN(ffname) + 5));
if (undo_file_name == NULL)
break;
p = gettail(undo_file_name);
#ifdef VMS
/* VMS can not handle more than one dot in the filenames
* use "dir/name" -> "dir/_un_name" - add _un_
* at the beginning to keep the extension */
mch_memmove(p + 4, p, STRLEN(p) + 1);
mch_memmove(p, "_un_", 4);
#else
/* Use same directory as the ffname,
* "dir/name" -> "dir/.name.un~" */
mch_memmove(p + 1, p, STRLEN(p) + 1);
*p = '.';
STRCAT(p, ".un~");
#endif
}
else
{
dir_name[dir_len] = NUL;
if (mch_isdir(dir_name))
{
if (munged_name == NULL)
{
munged_name = vim_strsave(ffname);
if (munged_name == NULL)
return NULL;
for (p = munged_name; *p != NUL; MB_PTR_ADV(p))
if (vim_ispathsep(*p))
*p = '%';
}
undo_file_name = concat_fnames(dir_name, munged_name, TRUE);
}
}
/* When reading check if the file exists. */
if (undo_file_name != NULL && (!reading
|| mch_stat((char *)undo_file_name, &st) >= 0))
break;
vim_free(undo_file_name);
undo_file_name = NULL;
}
vim_free(munged_name);
return undo_file_name;
}
static void
corruption_error(char *mesg, char_u *file_name)
{
EMSG3(_("E825: Corrupted undo file (%s): %s"), mesg, file_name);
}
static void
u_free_uhp(u_header_T *uhp)
{
u_entry_T *nuep;
u_entry_T *uep;
uep = uhp->uh_entry;
while (uep != NULL)
{
nuep = uep->ue_next;
u_freeentry(uep, uep->ue_size);
uep = nuep;
}
vim_free(uhp);
}
/*
* Write a sequence of bytes to the undo file.
* Buffers and encrypts as needed.
* Returns OK or FAIL.
*/
static int
undo_write(bufinfo_T *bi, char_u *ptr, size_t len)
{
#ifdef FEAT_CRYPT
if (bi->bi_buffer != NULL)
{
size_t len_todo = len;
char_u *p = ptr;
while (bi->bi_used + len_todo >= CRYPT_BUF_SIZE)
{
size_t n = CRYPT_BUF_SIZE - bi->bi_used;
mch_memmove(bi->bi_buffer + bi->bi_used, p, n);
len_todo -= n;
p += n;
bi->bi_used = CRYPT_BUF_SIZE;
if (undo_flush(bi) == FAIL)
return FAIL;
}
if (len_todo > 0)
{
mch_memmove(bi->bi_buffer + bi->bi_used, p, len_todo);
bi->bi_used += len_todo;
}
return OK;
}
#endif
if (fwrite(ptr, len, (size_t)1, bi->bi_fp) != 1)
return FAIL;
return OK;
}
#ifdef FEAT_CRYPT
static int
undo_flush(bufinfo_T *bi)
{
if (bi->bi_buffer != NULL && bi->bi_used > 0)
{
crypt_encode_inplace(bi->bi_state, bi->bi_buffer, bi->bi_used);
if (fwrite(bi->bi_buffer, bi->bi_used, (size_t)1, bi->bi_fp) != 1)
return FAIL;
bi->bi_used = 0;
}
return OK;
}
#endif
/*
* Write "ptr[len]" and crypt the bytes when needed.
* Returns OK or FAIL.
*/
static int
fwrite_crypt(bufinfo_T *bi, char_u *ptr, size_t len)
{
#ifdef FEAT_CRYPT
char_u *copy;
char_u small_buf[100];
size_t i;
if (bi->bi_state != NULL && bi->bi_buffer == NULL)
{
/* crypting every piece of text separately */
if (len < 100)
copy = small_buf; /* no malloc()/free() for short strings */
else
{
copy = lalloc(len, FALSE);
if (copy == NULL)
return 0;
}
crypt_encode(bi->bi_state, ptr, len, copy);
i = fwrite(copy, len, (size_t)1, bi->bi_fp);
if (copy != small_buf)
vim_free(copy);
return i == 1 ? OK : FAIL;
}
#endif
return undo_write(bi, ptr, len);
}
/*
* Write a number, MSB first, in "len" bytes.
* Must match with undo_read_?c() functions.
* Returns OK or FAIL.
*/
static int
undo_write_bytes(bufinfo_T *bi, long_u nr, int len)
{
char_u buf[8];
int i;
int bufi = 0;
for (i = len - 1; i >= 0; --i)
buf[bufi++] = (char_u)(nr >> (i * 8));
return undo_write(bi, buf, (size_t)len);
}
/*
* Write the pointer to an undo header. Instead of writing the pointer itself
* we use the sequence number of the header. This is converted back to
* pointers when reading. */
static void
put_header_ptr(bufinfo_T *bi, u_header_T *uhp)
{
undo_write_bytes(bi, (long_u)(uhp != NULL ? uhp->uh_seq : 0), 4);
}
static int
undo_read_4c(bufinfo_T *bi)
{
#ifdef FEAT_CRYPT
if (bi->bi_buffer != NULL)
{
char_u buf[4];
int n;
undo_read(bi, buf, (size_t)4);