/src/tmux/layout-custom.c

Source
/* $OpenBSD: layout-custom.c,v 1.44 2026/09/28 09:32:06 nicm Exp $ */

/*
 * Copyright (c) 2010 Nicholas Marriott <nicholas.marriott@gmail.com>
 *
 * 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 MIND, 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.
 */

#include <sys/types.h>

#include <ctype.h>
#include <errno.h>
#include <limits.h>
#include <stdarg.h>
#include <stdlib.h>
#include <string.h>

#include "tmux.h"

/*
 * Layouts can be represented as strings in a JSON format (v2). The version 1
 * format will be removed in the future and should no longer be used.
 *
 * The current (v2) format is JSON. The top level has two keys:
 *    "V": version number, currently 2
 *    "L": root layout cell
 *
 * Each cell is an object with:
 *    "t": cell type:
 *        "h": horizontal
 *        "v": vertical
 *        "p": pane
 *    "w": cell width
 *    "h": cell height
 *    "x": horizontal position
 *    "y": vertical position
 *
 * If the cell is a node cell (with child cells), it additionally has:
 *    "c": array of child cells
 *
 * If the cell is a leaf cell (that is, containing a pane and no child cells),
 * it additionally has:
 *    "I": pane ID as %n (currently ignored on parse)
 *    "l": index into last panes list if visited and not the active pane
 *    "a": true if the active pane
 *    "i": pane index
 *    "z": z-index, if a floating pane
 */

/* Maximum nesting depth for version 1 layouts. */
#define LAYOUT_V1_MAX_DEPTH 1000

/* Layout string. */
struct layout_string {
  char  *dat;
  size_t   size;    /* length written, not including terminator */
  size_t   capacity;  /* bytes allocated */
};

/* Layout parse cell context. */
struct layout_parse_cell_ctx {
  struct layout_cell  *lc;
  int      active;
  int      last;
  int      index;
  int      zindex;
};

/* Layout parse context. */
struct layout_parse_ctx {
  int64_t         version;
  int         num_active;
  struct layout_cell     *root;
  char        **cause;

  int         size;   /* number used */
  int         capacity; /* number allocated */
  struct layout_parse_cell_ctx   *cctxs;
};

static struct layout_cell *layout_find_bottomright(struct layout_cell *);
static u_short       layout_checksum(const char *);
static int       layout_append(struct layout_cell *,
             struct layout_string *, int);
static int       layout_construct(const char *,
             struct layout_parse_ctx *);
static void      layout_assign(struct window *,
             struct layout_parse_ctx *);
static void      layout_parse_apply_ctx(struct window *,
             struct layout_parse_ctx *);
static struct layout_cell *layout_parse_json_layout(struct json_node *,
             struct layout_cell *,
             struct layout_parse_ctx *);
static int       layout_parse_ctx_check_indexes(
             struct layout_parse_ctx *);

/* Compare cell contexts in ascending order of index. */
static int
layout_parse_index_cmp(const void *a, const void *b)
{
  const struct layout_parse_cell_ctx  *cca = a;
  const struct layout_parse_cell_ctx  *ccb = b;
  int          retval = 0;

  if (cca->index < ccb->index)
    retval = -1;
  if (cca->index > ccb->index)
    retval = 1;
  return (retval);
}

/* Compare cell contexts in descending order of z-index. */
static int
layout_parse_zindex_cmp(const void *a, const void *b)
{
  const struct layout_parse_cell_ctx  *cca = a;
  const struct layout_parse_cell_ctx  *ccb = b;
  int          retval = 0;

  if (cca->zindex > ccb->zindex)
    retval = -1;
  if (cca->zindex < ccb->zindex)
    retval = 1;
  return (retval);
}

/* Compare cell contexts in descending order of last. */
static int
layout_parse_last_cmp(const void *a, const void *b)
{
  const struct layout_parse_cell_ctx  *cca = a;
  const struct layout_parse_cell_ctx  *ccb = b;
  int          retval = 0;

  if (cca->last > ccb->last)
    retval = -1;
  if (cca->last < ccb->last)
    retval = 1;
  return (retval);
}

/* Initialize a layout string. */
static void
layout_string_init(struct layout_string *ls)
{
  ls->capacity = 1024;
  ls->dat = xmalloc(ls->capacity);
  ls->dat[0] = '\0';
  ls->size = 0;
}

/* Free a layout string. */
static void
layout_string_free(struct layout_string *ls)
{
  free(ls->dat);
  ls->dat = NULL;
  ls->size = 0;
  ls->capacity = 0;
}

/* Write an optionally formatted string to the end of the layout string. */
static void printflike(2, 3)
layout_string_write(struct layout_string *ls, const char *fmt, ...)
{
  va_list  ap;
  char  *s;
  int  slen;

  va_start(ap, fmt);
  slen = xvasprintf(&s, fmt, ap);
  va_end(ap);

  while (ls->size + slen + 1 > ls->capacity) {
    ls->dat = xreallocarray(ls->dat, 2, ls->capacity);
    ls->capacity *= 2;
  }
  memcpy(ls->dat + ls->size, s, slen);
  ls->size += slen;
  ls->dat[ls->size] = '\0';

  free(s);
}

/* Initialize a parse context. */
static void
layout_parse_init_ctx(struct layout_parse_ctx *pctx, char **cause)
{
  pctx->version = -1;
  pctx->num_active = 0;
  pctx->root = NULL;
  pctx->cause = cause;
  pctx->size = 0;
  pctx->capacity = 64;
  pctx->cctxs = xcalloc(pctx->capacity, sizeof *pctx->cctxs);
}

/* Free a parse context. */
static void
layout_parse_free_ctx(struct layout_parse_ctx *pctx)
{
  layout_free_cell(pctx->root, 0);
  pctx->root = NULL;
  free(pctx->cctxs);
  pctx->cctxs = NULL;
  pctx->size = 0;
  pctx->capacity = 0;
}

/* Add a cell context to the parse context. */
static void
layout_parse_add_cctx(struct layout_parse_ctx *pctx, struct layout_cell *lc,
    int active, int last, int index, int zindex)
{
  struct layout_parse_cell_ctx  *cctx;

  if (pctx->size >= pctx->capacity) {
    pctx->capacity *= 2;
    pctx->cctxs = xreallocarray(pctx->cctxs, pctx->capacity,
        sizeof *pctx->cctxs);
  }
  cctx = &pctx->cctxs[pctx->size++];

  cctx->lc = lc;
  cctx->active = active;
  cctx->last = last;
  cctx->index = index;
  cctx->zindex = zindex;
}

/* Remove a cell context from the parse context. Does not preserve ordering. */
static int
layout_parse_remove_cctx(struct layout_parse_ctx *pctx, struct layout_cell *lc)
{
  struct layout_parse_cell_ctx  *cctx;
  int        i;

  for (i = 0; i < pctx->size; i++) {
    if (lc == pctx->cctxs[i].lc) {
      cctx = &pctx->cctxs[--pctx->size];
      memmove(&pctx->cctxs[i], cctx, sizeof *cctx);
      return (0);
    }
  }
  return (-1);
}

/* Find the bottom-right cell. */
static struct layout_cell *
layout_find_bottomright(struct layout_cell *lc)
{
  if (lc->type == LAYOUT_WINDOWPANE)
    return (lc);
  lc = TAILQ_LAST(&lc->cells, layout_cells);
  return (layout_find_bottomright(lc));
}

/* Calculate layout checksum. */
static u_short
layout_checksum(const char *layout)
{
  u_short csum;

  csum = 0;
  for (; *layout != '\0'; layout++) {
    csum = (csum >> 1) + ((csum & 1) << 15);
    csum += *layout;
  }
  return (csum);
}

/* Dump layout as a string. */
char *
layout_dump(__unused struct window *w, struct layout_cell *lcroot, int flags)
{
  struct layout_string   layout_string = { 0 };
  char      *out;

  if (lcroot == NULL)
    goto bad;
  layout_string_init(&layout_string);
  if (layout_append(lcroot, &layout_string, flags) != 0)
    goto bad;
  if (~flags & LAYOUT_CUSTOM_OLD_FORMAT)
    xasprintf(&out, "{\"V\":2,\"L\":%s}", layout_string.dat);
  else {
    xasprintf(&out, "%04hx,%s", layout_checksum(layout_string.dat),
        layout_string.dat);
  }
  layout_string_free(&layout_string);
  return (out);

bad:
  layout_string_free(&layout_string);
  if (~flags & LAYOUT_CUSTOM_OLD_FORMAT)
    return (NULL);
  return (xstrdup("0000,"));
}

/* Get a floating pane cell's z-index in the layout being dumped. */
static u_int
layout_cell_zindex(struct layout_cell *lc)
{
  struct window_pane  *wp = lc->wp, *wq;
  struct window   *w = wp->window;
  struct layout_cell  *other;
  int      saved = (lc == wp->saved_layout_cell);
  u_int      i = 0;

  if (saved &&
      w->active != NULL &&
      (w->active->flags & PANE_ZOOMED) &&
      (w->active->saved_layout_cell->flags & LAYOUT_CELL_FLOATING)) {
    if (wp == w->active)
      return (0);
    i++;
  }
  TAILQ_FOREACH(wq, &w->z_index, zentry) {
    if (wq == wp)
      break;
    if (saved)
      other = wq->saved_layout_cell;
    else
      other = wq->layout_cell;
    if (other != NULL && (other->flags & LAYOUT_CELL_FLOATING))
      i++;
  }
  return (i);
}

/* Append information for a single cell in a JSON (v2) format. */
static int
layout_append_v2(struct layout_cell *lc, struct layout_string *ls)
{
  struct layout_cell  *lcchild;
  struct window_pane  *wp;
  enum layout_type   type;
  char       c;
  u_int      i, n, z;

  if (lc == NULL)
    return (-1);

  type = lc->type;
  if (type == LAYOUT_TOPBOTTOM)
    c = 'v';
  else if (type == LAYOUT_LEFTRIGHT)
    c = 'h';
  else if (type == LAYOUT_WINDOWPANE)
    c = 'p';
  else
    return (-1);

  layout_string_write(ls, "{\"t\":\"%c\",\"w\":%u,\"h\":%u,\"x\":%d"
      ",\"y\":%d", c, lc->g.sx, lc->g.sy, lc->g.xoff, lc->g.yoff);
  if (type != LAYOUT_WINDOWPANE) {
    layout_string_write(ls, ",\"c\":[");
    n = 0;
    TAILQ_FOREACH(lcchild, &lc->cells, entry) {
      if (layout_append_v2(lcchild, ls) != 0)
        return (-1);
      layout_string_write(ls, ",");
      n++;
    }
    if (n == 0)
      return (-1);
    ls->dat[--ls->size] = '\0'; /* removing trailing comma */
    layout_string_write(ls, "]");
  } else {
    wp = lc->wp;
    if (wp == NULL)
      return (-1);
    if (wp == wp->window->active)
      layout_string_write(ls, ",\"a\":true");
    else if (window_pane_last_index(wp, &i) == 0)
      layout_string_write(ls, ",\"l\":%u", i);
    if (window_pane_index(wp, &i) != 0)
      return (-1);
    layout_string_write(ls, ",\"i\":%u", i);
    if (lc->flags & LAYOUT_CELL_FLOATING) {
      z = layout_cell_zindex(lc);
      layout_string_write(ls, ",\"z\":%u", z);
    }
    layout_string_write(ls, ",\"I\":\"%%%u\"", wp->id);
  }

  layout_string_write(ls, "}");

  return (0);
}

/* Append information for a single cell in the version 1 format. */
static int
layout_append_v1(struct layout_cell *lc, struct layout_string *ls)
{
  struct layout_cell  *lcchild;
  const char    *brackets = "[]";

  if (lc == NULL)
    return (-1);

  if (lc->wp != NULL) {
    layout_string_write(ls, "%ux%u,%d,%d,%u", lc->g.sx, lc->g.sy,
        lc->g.xoff, lc->g.yoff, lc->wp->id);
  } else {
    layout_string_write(ls, "%ux%u,%d,%d", lc->g.sx, lc->g.sy,
        lc->g.xoff, lc->g.yoff);
  }
  switch (lc->type) {
  case LAYOUT_LEFTRIGHT:
    brackets = "{}";
    /* FALLTHROUGH */
  case LAYOUT_TOPBOTTOM:
    layout_string_write(ls, "%c", brackets[0]);
    TAILQ_FOREACH(lcchild, &lc->cells, entry) {
      if (layout_append_v1(lcchild, ls) != 0)
        return (-1);
      layout_string_write(ls, ",");
    }

    ls->dat[--ls->size] = '\0'; /* removing trailing comma */
    layout_string_write(ls, "%c", brackets[1]);
    break;
  case LAYOUT_WINDOWPANE:
    break;
  }

  return (0);
}

/*
 * Copies the tiled part of a layout. Only populates what is necessary to dump a
 * V1 layout string.
 */
static struct layout_cell *
layout_custom_copy_layout(struct layout_cell *lc)
{
  struct layout_cell  *lcchild, *lcnewchild, *lconly;
  struct layout_cell  *lcnew;

  if (lc->type == LAYOUT_WINDOWPANE &&
      (lc->flags & LAYOUT_CELL_FLOATING))
    return (NULL);

  lcnew = layout_create_cell(NULL);

  lcnew->type = lc->type;
  lcnew->flags = lc->flags;
  if (lc->type == LAYOUT_WINDOWPANE)
    lcnew->wp = lc->wp;
  layout_set_size(lcnew, lc->g.sx, lc->g.sy, lc->g.xoff, lc->g.yoff);

  switch (lc->type) {
  case LAYOUT_WINDOWPANE:
    break;
  case LAYOUT_TOPBOTTOM:
  case LAYOUT_LEFTRIGHT:
    TAILQ_FOREACH(lcchild, &lc->cells, entry) {
      lcnewchild = layout_custom_copy_layout(lcchild);
      if (lcnewchild == NULL)
        continue;
      TAILQ_INSERT_TAIL(&lcnew->cells, lcnewchild, entry);
      lcnewchild->parent = lcnew;
    }

    lconly = TAILQ_FIRST(&lcnew->cells);
    if (lconly == NULL) {
      layout_free_cell(lcnew, 0);
      return (NULL);
    }
    if (TAILQ_NEXT(lconly, entry) == NULL) {
      TAILQ_REMOVE(&lcnew->cells, lconly, entry);
      lconly->parent = NULL;
      layout_free_cell(lcnew, 0);
      return (lconly);
    }
    break;
  }

  return (lcnew);
}

/* Create a compatibility layout for dumping a V1 layout string. */
static struct layout_cell *
layout_custom_create_compat(struct layout_cell *lcroot)
{
  struct layout_cell  *lccompat;

  lccompat = layout_custom_copy_layout(lcroot);
  if (lccompat != NULL && layout_cell_is_tiled(lccompat)) {
    lccompat->g.xoff = 0;
    lccompat->g.yoff = 0;
  }

  return (lccompat);
}

/* Unlinks all panes from the given layout. */
static void
layout_custom_unlink_panes(struct layout_cell *lc)
{
  struct layout_cell  *lcchild;

  switch (lc->type) {
  case LAYOUT_WINDOWPANE:
    lc->wp = NULL;
    break;
  case LAYOUT_LEFTRIGHT:
  case LAYOUT_TOPBOTTOM:
    TAILQ_FOREACH(lcchild, &lc->cells, entry)
      layout_custom_unlink_panes(lcchild);
    break;
  }
}

/* Frees the compatibility layout. */
static void
layout_custom_free_compat(struct layout_cell *lcroot)
{
  if (lcroot == NULL)
    return;
  layout_custom_unlink_panes(lcroot);
  layout_free_cell(lcroot, 0);
}

/* Dispatch to append the appropriate version. */
static int
layout_append(struct layout_cell *lcroot, struct layout_string *ls, int flags)
{
  struct layout_cell  *lccompat;
  int      result;

  if (flags & LAYOUT_CUSTOM_OLD_FORMAT) {
    if (!layout_cell_is_tiled(lcroot) &&
        !layout_cell_has_tiled_child(lcroot))
      return (-1);
    lccompat = layout_custom_create_compat(lcroot);
    result = layout_append_v1(lccompat, ls);
    layout_custom_free_compat(lccompat);
  } else
    result = layout_append_v2(lcroot, ls);

  return (result);
}

/* Check layout sizes fit. */
static int
layout_check(struct layout_cell *lc)
{
  struct layout_cell  *lcchild;
  u_int      n = 0;

  switch (lc->type) {
  case LAYOUT_WINDOWPANE:
    break;
  case LAYOUT_LEFTRIGHT:
    TAILQ_FOREACH(lcchild, &lc->cells, entry) {
      if (!layout_cell_is_tiled(lcchild) &&
          !layout_cell_has_tiled_child(lcchild))
        continue;
      if (lcchild->g.sy != lc->g.sy)
        return (0);
      if (!layout_check(lcchild))
        return (0);
      n += lcchild->g.sx + 1;
    }
    if (n != 0 && n - 1 != lc->g.sx)
      return (0);
    break;
  case LAYOUT_TOPBOTTOM:
    TAILQ_FOREACH(lcchild, &lc->cells, entry) {
      if (!layout_cell_is_tiled(lcchild) &&
          !layout_cell_has_tiled_child(lcchild))
        continue;
      if (lcchild->g.sx != lc->g.sx)
        return (0);
      if (!layout_check(lcchild))
        return (0);
      n += lcchild->g.sy + 1;
    }
    if (n != 0 && n - 1 != lc->g.sy)
      return (0);
    break;
  }
  return (1);
}

/* Parse a layout string and arrange window as layout. */
int
layout_parse(struct window *w, const char *input, char **cause)
{
  struct window_pane  *wp;
  struct layout_cell  *lcchild, *lc = NULL;
  struct layout_parse_ctx  pctx;
  u_int      npanes, ncells, sx = 0, sy = 0;
  int      with_floating;

  /* Build the layout. */
  layout_parse_init_ctx(&pctx, cause);
  if (layout_construct(input, &pctx) != 0) {
    layout_parse_free_ctx(&pctx);
    return (-1);
  }
  with_floating = pctx.version > 1;

  /* Check this window will fit into the layout. */
  npanes = window_count_panes(w, with_floating);
  if (npanes == 0) {
    xasprintf(cause, "window @%u has no panes", w->id);
    goto fail;
  }
  for (;;) {
    ncells = layout_count_cells(pctx.root, with_floating);
    if (npanes > ncells) {
      xasprintf(cause, "have %u panes but need %u", npanes,
          ncells);
      goto fail;
    }
    if (npanes == ncells)
      break;

    /*
     * Fewer panes than cells, close the bottom right until none
     * remain.
     */
    lcchild = layout_find_bottomright(pctx.root);
    if (pctx.version > 1 && layout_parse_remove_cctx(&pctx,
        lcchild) != 0) {
      *cause = xstrdup("empty/missing layout parse context");
      goto fail;
    }
    layout_destroy_cell(NULL, lcchild, &pctx.root);
  }

  /* The root is now owned by lc. */
  lc = pctx.root;
  pctx.root = NULL;

  /*
   * It appears older versions of tmux were able to generate layouts with
   * an incorrect top cell size - if it is larger than the top child then
   * correct that (if this is still wrong the check code will catch it).
   */
  switch (lc->type) {
  case LAYOUT_WINDOWPANE:
    break;
  case LAYOUT_LEFTRIGHT:
    TAILQ_FOREACH(lcchild, &lc->cells, entry) {
      if (layout_cell_is_tiled(lcchild) ||
          layout_cell_has_tiled_child(lcchild)) {
        sy = lcchild->g.sy + 1;
        sx += lcchild->g.sx + 1;
      }
    }
    break;
  case LAYOUT_TOPBOTTOM:
    TAILQ_FOREACH(lcchild, &lc->cells, entry) {
      if (layout_cell_is_tiled(lcchild) ||
          layout_cell_has_tiled_child(lcchild)) {
        sx = lcchild->g.sx + 1;
        sy += lcchild->g.sy + 1;
      }
    }
    break;
  }
  if (lc->type != LAYOUT_WINDOWPANE && sx != 0 && sy != 0 &&
      (lc->g.sx != sx || lc->g.sy != sy)) {
    layout_print_cell(lc, __func__, 0);
    lc->g.sx = sx - 1; lc->g.sy = sy - 1;
  }

  /* Check the new layout. */
  if (!layout_check(lc)) {
    *cause = xstrdup("size mismatch after applying layout");
    goto fail;
  }

  /* Resize window to the layout size. */
  if (layout_cell_is_tiled(lc) ||
      layout_cell_has_tiled_child(lc))
    window_resize(w, lc->g.sx, lc->g.sy, -1, -1);

  /* Preserve floating panes for version 1. */
  if (pctx.version == 1) {
    TAILQ_FOREACH(wp, &w->panes, entry) {
      if (!window_pane_is_floating(wp))
        continue;
      lcchild = wp->layout_cell;
      TAILQ_REMOVE(&lcchild->parent->cells, lcchild, entry);
      lcchild->parent = NULL;
    }
  }

  /* Destroy the old layout and swap to the new. */
  layout_free_cell(w->layout_root, 0);
  w->layout_root = lc;

  /* Assign the panes into the cells. */
  layout_assign(w, &pctx);

  /* Update pane attributes. */
  layout_fix_offsets(w);
  layout_fix_panes(w, NULL);
  if (pctx.version > 1)
    layout_parse_apply_ctx(w, &pctx);
  recalculate_sizes();
  layout_print_cell(lc, __func__, 0);

  /* Backwards compatibility. */
  if (pctx.version == 1)
    events_fire_window("window-layout-changed", w);

  layout_parse_free_ctx(&pctx);
  return (0);

fail:
  layout_free_cell(lc, 0);
  layout_parse_free_ctx(&pctx);
  return (-1);
}

/* Assign panes into cells from the cell contexts. */
static void
layout_assign_from_ctx(struct window *w, struct layout_parse_ctx *pctx)
{
  struct layout_cell  *lc;
  struct window_pane  *wp;
  int      i;

  qsort(pctx->cctxs, pctx->size, sizeof pctx->cctxs[0],
      layout_parse_index_cmp);

  wp = TAILQ_FIRST(&w->panes);
  for (i = 0; i < pctx->size; i++) {
    lc = pctx->cctxs[i].lc;
    layout_make_leaf(lc, wp);
    wp = TAILQ_NEXT(wp, entry);
  }
}

/*
 * Assign tiled cells to available panes. Panes that already have a cell are
 * floating and are skipped over.
 */
static void
layout_assign_fallback_tiled(struct window_pane **wp, struct layout_cell *lc)
{
  struct layout_cell  *lcchild;

  if (lc == NULL)
    return;

  switch (lc->type) {
  case LAYOUT_WINDOWPANE:
    while (*wp != NULL && (*wp)->layout_cell != NULL)
      *wp = TAILQ_NEXT(*wp, entry);
    if (*wp == NULL)
      return;
    layout_make_leaf(lc, *wp);
    *wp = TAILQ_NEXT(*wp, entry);
    return;
  case LAYOUT_LEFTRIGHT:
  case LAYOUT_TOPBOTTOM:
    TAILQ_FOREACH(lcchild, &lc->cells, entry) {
      layout_assign_fallback_tiled(wp, lcchild);
    }
    return;
  }
}

/*
 * Assign panes into cells when there are no cell contexts. This will be removed
 * when the non-JSON format is deprecated.
 */
static void
layout_assign_fallback(struct window *w, struct layout_cell *lcroot)
{
  struct window_pane  *wp = TAILQ_FIRST(&w->panes);
  struct layout_cell  *lc;

  layout_assign_fallback_tiled(&wp, lcroot);

  if (window_count_panes(w, 1) > 1 &&
      lcroot->type == LAYOUT_WINDOWPANE)
    lcroot = layout_replace_with_node(w, lcroot, LAYOUT_TOPBOTTOM);

  wp = TAILQ_FIRST(&w->panes);
  while (wp != NULL) {
    if (window_pane_is_floating(wp)) {
      lc = wp->layout_cell;
      lc->parent = lcroot;
      TAILQ_INSERT_TAIL(&lcroot->cells, lc, entry);
    }
    wp = TAILQ_NEXT(wp, entry);
  }
}

/* Assign panes into cells. Number of cells must match the number of panes. */
static void
layout_assign(struct window *w, struct layout_parse_ctx *pctx)
{
  if (pctx->size > 0)
    layout_assign_from_ctx(w, pctx);
  else
    layout_assign_fallback(w, w->layout_root);
}

/* Construct a cell from the version 1 format. */
static struct layout_cell *
layout_construct_cell(struct layout_cell *lcparent, const char **layout)
{
  struct layout_cell     *lc;
  u_int     sx, sy;
  int     xoff, yoff;
  const char         *saved;

  if (!isdigit((u_char) **layout))
    return (NULL);
  if (sscanf(*layout, "%5ux%5u,%5d,%5d", &sx, &sy, &xoff, &yoff) != 4)
    return (NULL);
  if (sx < PANE_MINIMUM || sx > PANE_MAXIMUM ||
      sy < PANE_MINIMUM || sy > PANE_MAXIMUM ||
      xoff < 0 || xoff > WINDOW_MAXIMUM ||
      yoff < 0 || yoff > WINDOW_MAXIMUM)
    return (NULL);

  while (isdigit((u_char) **layout))
    (*layout)++;
  if (**layout != 'x')
    return (NULL);
  (*layout)++;
  while (isdigit((u_char) **layout))
    (*layout)++;
  if (**layout != ',')
    return (NULL);
  (*layout)++;
  while (isdigit((u_char) **layout))
    (*layout)++;
  if (**layout != ',')
    return (NULL);
  (*layout)++;
  while (isdigit((u_char) **layout))
    (*layout)++;
  if (**layout == ',') {
    saved = *layout;
    (*layout)++;
    while (isdigit((u_char) **layout))
      (*layout)++;
    if (**layout == 'x')
      *layout = saved;
  }

  lc = layout_create_cell(lcparent);
  lc->g.sx = sx;
  lc->g.sy = sy;
  lc->g.xoff = xoff;
  lc->g.yoff = yoff;

  return (lc);
}

/* Construct a layout from the version 1 format. */
static struct layout_cell *
layout_construct_v1(struct layout_cell *lcparent, const char **layout, u_int depth)
{
  struct layout_cell  *lc, *lcchild;

  if (depth > LAYOUT_V1_MAX_DEPTH)
    return (NULL);

  lc = layout_construct_cell(lcparent, layout);
  if (lc == NULL)
    return (NULL);

  switch (**layout) {
  case ',':
  case '}':
  case ']':
  case '\0':
    return (lc);
  case '{':
    lc->type = LAYOUT_LEFTRIGHT;
    break;
  case '[':
    lc->type = LAYOUT_TOPBOTTOM;
    break;
  default:
    goto fail;
  }

  do {
    (*layout)++;
    lcchild = layout_construct_v1(lc, layout, depth + 1);
    if (lcchild == NULL)
      goto fail;
    TAILQ_INSERT_TAIL(&lc->cells, lcchild, entry);
  } while (**layout == ',');

  switch (lc->type) {
  case LAYOUT_LEFTRIGHT:
    if (**layout != '}')
      goto fail;
    break;
  case LAYOUT_TOPBOTTOM:
    if (**layout != ']')
      goto fail;
    break;
  default:
    goto fail;
  }
  (*layout)++;

  return (lc);

fail:
  layout_free_cell(lc, 0);
  return (NULL);
}

/*
 * Evaluate parsed JSON. Check metadata at the top level and return the new
 * layout root. Consumes json input.
 */
static int
layout_parse_json(struct json_node *jnroot, struct layout_parse_ctx *pctx)
{
  struct json_node   *jn, *object;
  int64_t       num;
  char      **cause = pctx->cause;

  if (json_get_object(jnroot, &jn) != 0) {
    *cause = xstrdup("invalid layout json");
    goto fail;
  }

  if (json_find_number(jn, "V", &num, cause) != 0)
    goto fail;
  pctx->version = num;

  if (json_find_object(jn, "L", &object, cause) != 0)
    goto fail;
  pctx->root = layout_parse_json_layout(object, NULL, pctx);
  if (pctx->root == NULL)
    goto fail;

  json_destroy_node(jnroot);

  return (0);

fail:
  json_destroy_node(jnroot);
  if (pctx->root != NULL)
    layout_free_cell(pctx->root, 0);
  pctx->root = NULL;
  return (-1);
}

/* Parse nodes into layout cells. */
static struct layout_cell *
layout_parse_json_layout(struct json_node *node, struct layout_cell *lcparent,
    struct layout_parse_ctx *pctx)
{
  struct json_node   *member, *array;
  struct layout_cell   *lc = layout_create_cell(lcparent), *lcchild;
  const char     *str;
  int64_t       num;
  char      **cause = pctx->cause;
  int       boolean, index, zindex, active = -1;
  int       last = -1;

  if (json_find_string(node, "t", &str, cause) != 0)
    goto fail;
  if (strcmp(str, "p") == 0)
    lc->type = LAYOUT_WINDOWPANE;
  else if (strcmp(str, "v") == 0)
    lc->type = LAYOUT_TOPBOTTOM;
  else if (strcmp(str, "h") == 0)
    lc->type = LAYOUT_LEFTRIGHT;
  else {
    xasprintf(cause, "unknown cell type \"%s\"", str);
    goto fail;
  }

  if (json_find_number(node, "w", &num, cause) != 0)
    goto fail;
  if (num < PANE_MINIMUM || num > PANE_MAXIMUM) {
    xasprintf(cause, "invalid width %lld", (long long)num);
    goto fail;
  }
  lc->g.sx = num;

  if (json_find_number(node, "h", &num, cause) != 0)
    goto fail;
  if (num < PANE_MINIMUM || num > PANE_MAXIMUM) {
    xasprintf(cause, "invalid height %lld", (long long)num);
    goto fail;
  }
  lc->g.sy = num;

  if (json_find_number(node, "x", &num, cause) != 0)
    goto fail;
  if (num < -WINDOW_MAXIMUM || num > WINDOW_MAXIMUM) {
    xasprintf(cause, "invalid x-offset %lld", (long long)num);
    goto fail;
  }
  lc->g.xoff = num;

  if (json_find_number(node, "y", &num, cause) != 0)
    goto fail;
  if (num < -WINDOW_MAXIMUM || num > WINDOW_MAXIMUM) {
    xasprintf(cause, "invalid y-offset %lld", (long long)num);
    goto fail;
  }
  lc->g.yoff = num;

  if (lc->type == LAYOUT_WINDOWPANE) { /* "I" is currently ignored */
    if (json_find(node, "c") != NULL) {
      *cause = xstrdup("panes cannot have children");
      goto fail;
    }
    if (json_find_number(node, "i", &num, cause) != 0)
      goto fail;
    if (num < 0 || num > INT_MAX) {
      xasprintf(cause, "invalid index %lld", (long long)num);
      goto fail;
    }
    index = num;

    if (json_find(node, "a") != NULL) {
      if (json_find_boolean(node, "a", &boolean, cause) != 0)
        goto fail;
      active = boolean;
      if (active)
        pctx->num_active++;
    } else if (json_find(node, "l") != NULL) {
      if (json_find_number(node, "l", &num, cause) != 0)
        goto fail;
      if (num < 0 || num > INT_MAX) {
        xasprintf(cause, "invalid last %lld",
            (long long)num);
        goto fail;
      }
      last = num;
    }

    if (json_find(node, "z") != NULL) {
      if (json_find_number(node, "z", &num, cause) != 0)
        goto fail;
      if (num < 0 || num > INT_MAX - 1) {
        xasprintf(cause, "invalid floating zindex %lld",
            (long long)num);
        goto fail;
      }
      zindex = num;
      lc->flags |= LAYOUT_CELL_FLOATING;
    } else
      zindex = INT_MAX;

    layout_parse_add_cctx(pctx, lc, active, last, index, zindex);
  } else {
    if (json_find_array(node, "c", &array, cause) != 0)
      goto fail;
    if ((member = json_array_first(array)) == NULL ||
        json_array_next(member) == NULL) {
      *cause = xstrdup("nodes must have more than one child");
      goto fail;
    }
    while (member != NULL) {
      lcchild = layout_parse_json_layout(member, lc,
        pctx);
      if (lcchild == NULL)
        goto fail;
      TAILQ_INSERT_TAIL(&lc->cells, lcchild, entry);
      member = json_array_next(member);
    }
  }

  return (lc);

fail:
  layout_free_cell(lc, 0);
  return (NULL);
}

/* Construct a layout root from a formatted string. */
static int
layout_construct(const char *input, struct layout_parse_ctx *pctx)
{
  struct json_node  *json;
  u_short      csum;
  int      n = 0;

  while (isspace((u_char) *input))
    input++;

  if (*input != '{') { /* sniffing version */
    if (sscanf(input, "%hx,%n", &csum, &n) != 1 || n != 5) {
      *pctx->cause = xstrdup("malformed layout header");
      return (-1);
    }
    input += n;
    if (csum != layout_checksum(input)) {
      *pctx->cause = xstrdup("invalid layout checksum");
      return (-1);
    }
    pctx->root = layout_construct_v1(NULL, &input, 0);
    if (pctx->root == NULL) {
      *pctx->cause = xstrdup("invalid layout");
      return (-1);
    }
    if (*input != '\0') {
      *pctx->cause = xstrdup("trailing data");
      return (-1);
    }
    pctx->version = 1;
  } else {
    if ((json = json_parse(input, pctx->cause)) == NULL)
      return (-1);

    if (layout_parse_json(json, pctx) != 0)
      return (-1);

    if (pctx->version != 2) {
      *pctx->cause = xstrdup("version mismatch");
      return (-1);
    }
    if (pctx->num_active > 1) {
      *pctx->cause = xstrdup("more than one active pane");
      return (-1);
    }
    if (pctx->size == 0) {
      *pctx->cause = xstrdup("no panes");
      return (-1);
    }
    if (!layout_parse_ctx_check_indexes(pctx))
      return (-1);
  }

  return (0);
}

/* Apply the remaining context to the layout. */
static void
layout_parse_apply_ctx(struct window *w, struct layout_parse_ctx *pctx)
{
  struct layout_parse_cell_ctx   *cctx;
  struct window_pane     *wp, *wpnext;
  int         i;

  /* Apply z-indexes. */
  wp = TAILQ_FIRST(&w->z_index);
  while (wp != NULL) {
    wpnext = TAILQ_NEXT(wp, zentry);
    if (window_pane_is_floating(wp))
      TAILQ_REMOVE(&w->z_index, wp, zentry);
    wp = wpnext;
  }

  qsort(pctx->cctxs, pctx->size, sizeof pctx->cctxs[0],
      layout_parse_zindex_cmp);

  for (i = 0; i < pctx->size; i++) {
    cctx = &pctx->cctxs[i];
    wp = cctx->lc->wp;
    if (window_pane_is_floating(wp))
      TAILQ_INSERT_HEAD(&w->z_index, wp, zentry);
  }

  /* Set the active pane. */
  for (i = 0; i < pctx->size; i++) {
    cctx = &pctx->cctxs[i];
    if (cctx->active == 1) {
      window_set_active_pane(w, cctx->lc->wp, 1);
      break;
    }
  }

  /* Apply last panes. */
  while (!TAILQ_EMPTY(&w->last_panes)) {
    wp = TAILQ_FIRST(&w->last_panes);
    window_pane_stack_remove(&w->last_panes, wp);
  }

  qsort(pctx->cctxs, pctx->size, sizeof pctx->cctxs[0],
      layout_parse_last_cmp);

  for (i = 0; i < pctx->size; i++) {
    cctx = &pctx->cctxs[i];
    wp = cctx->lc->wp;
    if (cctx->last < 0 || cctx->active == 1)
      continue;
    window_pane_stack_push(&w->last_panes, wp);
  }
}

/* Checks for duplicate pane indexes, z-indexes, and last indexes. */
static int
layout_parse_ctx_check_indexes(struct layout_parse_ctx *pctx)
{
  int i, n;

  qsort(pctx->cctxs, pctx->size, sizeof pctx->cctxs[0],
      layout_parse_index_cmp);

  for (i = 1; i < pctx->size; i++) {
    if (pctx->cctxs[i].index == pctx->cctxs[i - 1].index) {
      *pctx->cause = xstrdup("duplicate pane index");
      return (0);
    }
  }

  qsort(pctx->cctxs, pctx->size, sizeof pctx->cctxs[0],
      layout_parse_zindex_cmp);

  /*
   * Sorted in descending order, so the panes without a z-index come first
   * and the floating panes run to the end.
   */
  n = 0;
  while (n < pctx->size && pctx->cctxs[n].zindex == INT_MAX)
    n++;
  for (i = n + 1; i < pctx->size; i++) {
    if (pctx->cctxs[i].zindex == pctx->cctxs[i - 1].zindex) {
      *pctx->cause = xstrdup("duplicate pane z-index");
      return (0);
    }
  }

  qsort(pctx->cctxs, pctx->size, sizeof pctx->cctxs[0],
      layout_parse_last_cmp);

  /*
   * Sorted in descending order, so the panes without a last index come
   * last.
   */
  n = 0;
  while (n < pctx->size && pctx->cctxs[n].last >= 0)
    n++;
  for (i = 1; i < n; i++) {
    if (pctx->cctxs[i].last == pctx->cctxs[i - 1].last) {
      *pctx->cause = xstrdup("duplicate last pane index");
      return (0);
    }
  }

  return (1);
}

Coverage Report

Created: 2026-10-17 06:18