* Copyright (c) 2016, 2017 Ingo Schwarze <schwarze@openbsd.org>

/* Id: dba.c,v 1.10 2017/02/17 14:43:54 schwarze Exp */
/*
* Copyright (c) 2016, 2017 Ingo Schwarze <[email protected]>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*
* Allocation-based version of the mandoc database, for read-write access.
* The interface is defined in "dba.h".
*/
#include "config.h"

#include <sys/types.h>
#if HAVE_ENDIAN
#include <endian.h>
#elif HAVE_SYS_ENDIAN
#include <sys/endian.h>
#elif HAVE_NTOHL
#include <arpa/inet.h>
#endif
#include <errno.h>
#include <stddef.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "mandoc_aux.h"
#include "mandoc_ohash.h"
#include "mansearch.h"
#include "dba_write.h"
#include "dba_array.h"
#include "dba.h"

struct macro_entry {
struct dba_array *pages;
char value[];
};

static void *prepend(const char *, char);
static void dba_pages_write(struct dba_array *);
static int compare_names(const void *, const void *);
static int compare_strings(const void *, const void *);

static struct macro_entry
*get_macro_entry(struct ohash *, const char *, int32_t);
static void dba_macros_write(struct dba_array *);
static void dba_macro_write(struct ohash *);
static int compare_entries(const void *, const void *);

/*** top-level functions **********************************************/

struct dba *
dba_new(int32_t npages)
{
struct dba *dba;
struct ohash *macro;
int32_t im;

dba = mandoc_malloc(sizeof(*dba));
dba->pages = dba_array_new(npages, DBA_GROW);
dba->macros = dba_array_new(MACRO_MAX, 0);
for (im = 0; im < MACRO_MAX; im++) {
macro = mandoc_malloc(sizeof(*macro));
mandoc_ohash_init(macro, 4,
offsetof(struct macro_entry, value));
dba_array_set(dba->macros, im, macro);
}
return dba;
}

void
dba_free(struct dba *dba)
{
struct dba_array *page;
struct ohash *macro;
struct macro_entry *entry;
unsigned int slot;

dba_array_FOREACH(dba->macros, macro) {
for (entry = ohash_first(macro, &slot); entry != NULL;
entry = ohash_next(macro, &slot)) {
dba_array_free(entry->pages);
free(entry);
}
ohash_delete(macro);
free(macro);
}
dba_array_free(dba->macros);

dba_array_undel(dba->pages);
dba_array_FOREACH(dba->pages, page) {
dba_array_free(dba_array_get(page, DBP_NAME));
dba_array_free(dba_array_get(page, DBP_SECT));
dba_array_free(dba_array_get(page, DBP_ARCH));
free(dba_array_get(page, DBP_DESC));
dba_array_free(dba_array_get(page, DBP_FILE));
dba_array_free(page);
}
dba_array_free(dba->pages);

free(dba);
}

/*
* Write the complete mandoc database to disk; the format is:
* - One integer each for magic and version.
* - One pointer each to the macros table and to the final magic.
* - The pages table.
* - The macros table.
* - And at the very end, the magic integer again.
*/
int
dba_write(const char *fname, struct dba *dba)
{
int save_errno;
int32_t pos_end, pos_macros, pos_macros_ptr;

if (dba_open(fname) == -1)
return -1;
dba_int_write(MANDOCDB_MAGIC);
dba_int_write(MANDOCDB_VERSION);
pos_macros_ptr = dba_skip(1, 2);
dba_pages_write(dba->pages);
pos_macros = dba_tell();
dba_macros_write(dba->macros);
pos_end = dba_tell();
dba_int_write(MANDOCDB_MAGIC);
dba_seek(pos_macros_ptr);
dba_int_write(pos_macros);
dba_int_write(pos_end);
if (dba_close() == -1) {
save_errno = errno;
unlink(fname);
errno = save_errno;
return -1;
}
return 0;
}

/*** functions for handling pages *************************************/

/*
* Create a new page and append it to the pages table.
*/
struct dba_array *
dba_page_new(struct dba_array *pages, const char *arch,
const char *desc, const char *file, enum form form)
{
struct dba_array *page, *entry;

page = dba_array_new(DBP_MAX, 0);
entry = dba_array_new(1, DBA_STR | DBA_GROW);
dba_array_add(page, entry);
entry = dba_array_new(1, DBA_STR | DBA_GROW);
dba_array_add(page, entry);
if (arch != NULL && *arch != '\0') {
entry = dba_array_new(1, DBA_STR | DBA_GROW);
dba_array_add(entry, __UNCONST(arch));
} else
entry = NULL;
dba_array_add(page, entry);
dba_array_add(page, mandoc_strdup(desc));
entry = dba_array_new(1, DBA_STR | DBA_GROW);
dba_array_add(entry, prepend(file, form));
dba_array_add(page, entry);
dba_array_add(pages, page);
return page;
}

/*
* Add a section, architecture, or file name to an existing page.
* Passing the NULL pointer for the architecture makes the page MI.
* In that case, any earlier or later architectures are ignored.
*/
void
dba_page_add(struct dba_array *page, int32_t ie, const char *str)
{
struct dba_array *entries;
char *entry;

entries = dba_array_get(page, ie);
if (ie == DBP_ARCH) {
if (entries == NULL)
return;
if (str == NULL || *str == '\0') {
dba_array_free(entries);
dba_array_set(page, DBP_ARCH, NULL);
return;
}
}
if (*str == '\0')
return;
dba_array_FOREACH(entries, entry) {
if (ie == DBP_FILE && *entry < ' ')
entry++;
if (strcmp(entry, str) == 0)
return;
}
dba_array_add(entries, __UNCONST(str));
}

/*
* Add an additional name to an existing page.
*/
void
dba_page_alias(struct dba_array *page, const char *name, uint64_t mask)
{
struct dba_array *entries;
char *entry;
char maskbyte;

if (*name == '\0')
return;
maskbyte = mask & NAME_MASK;
entries = dba_array_get(page, DBP_NAME);
dba_array_FOREACH(entries, entry) {
if (strcmp(entry + 1, name) == 0) {
*entry |= maskbyte;
return;
}
}
dba_array_add(entries, prepend(name, maskbyte));
}

/*
* Return a pointer to a temporary copy of instr with inbyte prepended.
*/
static void *
prepend(const char *instr, char inbyte)
{
static char *outstr = NULL;
static size_t outlen = 0;
size_t newlen;

newlen = strlen(instr) + 1;
if (newlen > outlen) {
outstr = mandoc_realloc(outstr, newlen + 1);
outlen = newlen;
}
*outstr = inbyte;
memcpy(outstr + 1, instr, newlen);
return outstr;
}

/*
* Write the pages table to disk; the format is:
* - One integer containing the number of pages.
* - For each page, five pointers to the names, sections,
* architectures, description, and file names of the page.
* MI pages write 0 instead of the architecture pointer.
* - One list each for names, sections, architectures, descriptions and
* file names. The description for each page ends with a NUL byte.
* For all the other lists, each string ends with a NUL byte,
* and the last string for a page ends with two NUL bytes.
* - To assure alignment of following integers,
* the end is padded with NUL bytes up to a multiple of four bytes.
*/
static void
dba_pages_write(struct dba_array *pages)
{
struct dba_array *page, *entry;
int32_t pos_pages, pos_end;

pos_pages = dba_array_writelen(pages, 5);
dba_array_FOREACH(pages, page) {
dba_array_setpos(page, DBP_NAME, dba_tell());
entry = dba_array_get(page, DBP_NAME);
dba_array_sort(entry, compare_names);
dba_array_writelst(entry);
}
dba_array_FOREACH(pages, page) {
dba_array_setpos(page, DBP_SECT, dba_tell());
entry = dba_array_get(page, DBP_SECT);
dba_array_sort(entry, compare_strings);
dba_array_writelst(entry);
}
dba_array_FOREACH(pages, page) {
if ((entry = dba_array_get(page, DBP_ARCH)) != NULL) {
dba_array_setpos(page, DBP_ARCH, dba_tell());
dba_array_sort(entry, compare_strings);
dba_array_writelst(entry);
} else
dba_array_setpos(page, DBP_ARCH, 0);
}
dba_array_FOREACH(pages, page) {
dba_array_setpos(page, DBP_DESC, dba_tell());
dba_str_write(dba_array_get(page, DBP_DESC));
}
dba_array_FOREACH(pages, page) {
dba_array_setpos(page, DBP_FILE, dba_tell());
dba_array_writelst(dba_array_get(page, DBP_FILE));
}
pos_end = dba_align();
dba_seek(pos_pages);
dba_array_FOREACH(pages, page)
dba_array_writepos(page);
dba_seek(pos_end);
}

static int
compare_names(const void *vp1, const void *vp2)
{
const char *cp1, *cp2;
int diff;

cp1 = *(const char * const *)vp1;
cp2 = *(const char * const *)vp2;
return (diff = *cp2 - *cp1) ? diff :
strcasecmp(cp1 + 1, cp2 + 1);
}

static int
compare_strings(const void *vp1, const void *vp2)
{
const char *cp1, *cp2;

cp1 = *(const char * const *)vp1;
cp2 = *(const char * const *)vp2;
return strcmp(cp1, cp2);
}

/*** functions for handling macros ************************************/

/*
* In the hash table for a single macro, look up an entry by
* the macro value or add an empty one if it doesn't exist yet.
*/
static struct macro_entry *
get_macro_entry(struct ohash *macro, const char *value, int32_t np)
{
struct macro_entry *entry;
size_t len;
unsigned int slot;

slot = ohash_qlookup(macro, value);
if ((entry = ohash_find(macro, slot)) == NULL) {
len = strlen(value) + 1;
entry = mandoc_malloc(sizeof(*entry) + len);
memcpy(&entry->value, value, len);
entry->pages = dba_array_new(np, DBA_GROW);
ohash_insert(macro, slot, entry);
}
return entry;
}

/*
* In addition to get_macro_entry(), add multiple page references,
* converting them from the on-disk format (byte offsets in the file)
* to page pointers in memory.
*/
void
dba_macro_new(struct dba *dba, int32_t im, const char *value,
const int32_t *pp)
{
struct macro_entry *entry;
const int32_t *ip;
int32_t np;

np = 0;
for (ip = pp; *ip; ip++)
np++;

entry = get_macro_entry(dba_array_get(dba->macros, im), value, np);
for (ip = pp; *ip; ip++)
dba_array_add(entry->pages, dba_array_get(dba->pages,
be32toh(*ip) / 5 / sizeof(*ip) - 1));
}

/*
* In addition to get_macro_entry(), add one page reference,
* directly taking the in-memory page pointer as an argument.
*/
void
dba_macro_add(struct dba_array *macros, int32_t im, const char *value,
struct dba_array *page)
{
struct macro_entry *entry;

if (*value == '\0')
return;
entry = get_macro_entry(dba_array_get(macros, im), value, 1);
dba_array_add(entry->pages, page);
}

/*
* Write the macros table to disk; the format is:
* - The number of macro tables (actually, MACRO_MAX).
* - That number of pointers to the individual macro tables.
* - The individual macro tables.
*/
static void
dba_macros_write(struct dba_array *macros)
{
struct ohash *macro;
int32_t im, pos_macros, pos_end;

pos_macros = dba_array_writelen(macros, 1);
im = 0;
dba_array_FOREACH(macros, macro) {
dba_array_setpos(macros, im++, dba_tell());
dba_macro_write(macro);
}
pos_end = dba_tell();
dba_seek(pos_macros);
dba_array_writepos(macros);
dba_seek(pos_end);
}

/*
* Write one individual macro table to disk; the format is:
* - The number of entries in the table.
* - For each entry, two pointers, the first one to the value
* and the second one to the list of pages.
* - A list of values, each ending in a NUL byte.
* - To assure alignment of following integers,
* padding with NUL bytes up to a multiple of four bytes.
* - A list of pointers to pages, each list ending in a 0 integer.
*/
static void
dba_macro_write(struct ohash *macro)
{
struct macro_entry **entries, *entry;
struct dba_array *page;
int32_t *kpos, *dpos;
unsigned int ie, ne, slot;
int use;
int32_t addr, pos_macro, pos_end;

/* Temporary storage for filtering and sorting. */

ne = ohash_entries(macro);
entries = mandoc_reallocarray(NULL, ne, sizeof(*entries));
kpos = mandoc_reallocarray(NULL, ne, sizeof(*kpos));
dpos = mandoc_reallocarray(NULL, ne, sizeof(*dpos));

/* Build a list of non-empty entries and sort it. */

ne = 0;
for (entry = ohash_first(macro, &slot); entry != NULL;
entry = ohash_next(macro, &slot)) {
use = 0;
dba_array_FOREACH(entry->pages, page)
if (dba_array_getpos(page))
use = 1;
if (use)
entries[ne++] = entry;
}
qsort(entries, ne, sizeof(*entries), compare_entries);

/* Number of entries, and space for the pointer pairs. */

dba_int_write(ne);
pos_macro = dba_skip(2, ne);

/* String table. */

for (ie = 0; ie < ne; ie++) {
kpos[ie] = dba_tell();
dba_str_write(entries[ie]->value);
}
dba_align();

/* Pages table. */

for (ie = 0; ie < ne; ie++) {
dpos[ie] = dba_tell();
dba_array_FOREACH(entries[ie]->pages, page)
if ((addr = dba_array_getpos(page)))
dba_int_write(addr);
dba_int_write(0);
}
pos_end = dba_tell();

/* Fill in the pointer pairs. */

dba_seek(pos_macro);
for (ie = 0; ie < ne; ie++) {
dba_int_write(kpos[ie]);
dba_int_write(dpos[ie]);
}
dba_seek(pos_end);

free(entries);
free(kpos);
free(dpos);
}

static int
compare_entries(const void *vp1, const void *vp2)
{
const struct macro_entry *ep1, *ep2;

ep1 = *(const struct macro_entry * const *)vp1;
ep2 = *(const struct macro_entry * const *)vp2;
return strcmp(ep1->value, ep2->value);
}