Import vim from changeset v5628:c9cad40b4181

- Cleanup source tree, leaving only files necessary for compilation/testing
- Process files through unifdef to remove tons of FEAT_* macros
- Process files through uncrustify to normalize source code formatting.
- Port the build system to cmake

1 files changed, 2296 insertions, 0 deletions

diff --git a/src/diff.c b/src/diff.c
new file mode 100644
index 0000000000..ad31128575
--- /dev/null
+++ b/src/diff.c
@@ -0,0 +1,2296 @@
+/* vim:set ts=8 sts=4 sw=4:
+ *
+ * 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.
+ */
+
+/*
+ * diff.c: code for diff'ing two, three or four buffers.
+ */
+
+#include "vim.h"
+
+
+static int diff_busy = FALSE;           /* ex_diffgetput() is busy */
+
+/* flags obtained from the 'diffopt' option */
+#define DIFF_FILLER     1       /* display filler lines */
+#define DIFF_ICASE      2       /* ignore case */
+#define DIFF_IWHITE     4       /* ignore change in white space */
+#define DIFF_HORIZONTAL 8       /* horizontal splits */
+#define DIFF_VERTICAL   16      /* vertical splits */
+static int diff_flags = DIFF_FILLER;
+
+#define LBUFLEN 50              /* length of line in diff file */
+
+static int diff_a_works = MAYBE; /* TRUE when "diff -a" works, FALSE when it
+                                    doesn't work, MAYBE when not checked yet */
+
+static int diff_buf_idx __ARGS((buf_T *buf));
+static int diff_buf_idx_tp __ARGS((buf_T *buf, tabpage_T *tp));
+static void diff_mark_adjust_tp __ARGS((tabpage_T *tp, int idx, linenr_T line1,
+                                        linenr_T line2, long amount,
+                                        long amount_after));
+static void diff_check_unchanged __ARGS((tabpage_T *tp, diff_T *dp));
+static int diff_check_sanity __ARGS((tabpage_T *tp, diff_T *dp));
+static void diff_redraw __ARGS((int dofold));
+static int diff_write __ARGS((buf_T *buf, char_u *fname));
+static void diff_file __ARGS((char_u *tmp_orig, char_u *tmp_new,
+                              char_u *tmp_diff));
+static int diff_equal_entry __ARGS((diff_T *dp, int idx1, int idx2));
+static int diff_cmp __ARGS((char_u *s1, char_u *s2));
+static void diff_fold_update __ARGS((diff_T *dp, int skip_idx));
+static void diff_read __ARGS((int idx_orig, int idx_new, char_u *fname));
+static void diff_copy_entry __ARGS((diff_T *dprev, diff_T *dp, int idx_orig,
+                                    int idx_new));
+static diff_T *diff_alloc_new __ARGS((tabpage_T *tp, diff_T *dprev, diff_T *dp));
+
+#ifndef USE_CR
+# define tag_fgets vim_fgets
+#endif
+
+/*
+ * Called when deleting or unloading a buffer: No longer make a diff with it.
+ */
+void diff_buf_delete(buf)
+buf_T       *buf;
+{
+  int i;
+  tabpage_T   *tp;
+
+  for (tp = first_tabpage; tp != NULL; tp = tp->tp_next) {
+    i = diff_buf_idx_tp(buf, tp);
+    if (i != DB_COUNT) {
+      tp->tp_diffbuf[i] = NULL;
+      tp->tp_diff_invalid = TRUE;
+      if (tp == curtab)
+        diff_redraw(TRUE);
+    }
+  }
+}
+
+/*
+ * Check if the current buffer should be added to or removed from the list of
+ * diff buffers.
+ */
+void diff_buf_adjust(win)
+win_T       *win;
+{
+  win_T       *wp;
+  int i;
+
+  if (!win->w_p_diff) {
+    /* When there is no window showing a diff for this buffer, remove
+     * it from the diffs. */
+    for (wp = firstwin; wp != NULL; wp = wp->w_next)
+      if (wp->w_buffer == win->w_buffer && wp->w_p_diff)
+        break;
+    if (wp == NULL) {
+      i = diff_buf_idx(win->w_buffer);
+      if (i != DB_COUNT) {
+        curtab->tp_diffbuf[i] = NULL;
+        curtab->tp_diff_invalid = TRUE;
+        diff_redraw(TRUE);
+      }
+    }
+  } else
+    diff_buf_add(win->w_buffer);
+}
+
+/*
+ * Add a buffer to make diffs for.
+ * Call this when a new buffer is being edited in the current window where
+ * 'diff' is set.
+ * Marks the current buffer as being part of the diff and requiring updating.
+ * This must be done before any autocmd, because a command may use info
+ * about the screen contents.
+ */
+void diff_buf_add(buf)
+buf_T       *buf;
+{
+  int i;
+
+  if (diff_buf_idx(buf) != DB_COUNT)
+    return;             /* It's already there. */
+
+  for (i = 0; i < DB_COUNT; ++i)
+    if (curtab->tp_diffbuf[i] == NULL) {
+      curtab->tp_diffbuf[i] = buf;
+      curtab->tp_diff_invalid = TRUE;
+      diff_redraw(TRUE);
+      return;
+    }
+
+  EMSGN(_("E96: Can not diff more than %ld buffers"), DB_COUNT);
+}
+
+/*
+ * Find buffer "buf" in the list of diff buffers for the current tab page.
+ * Return its index or DB_COUNT if not found.
+ */
+static int diff_buf_idx(buf)
+buf_T       *buf;
+{
+  int idx;
+
+  for (idx = 0; idx < DB_COUNT; ++idx)
+    if (curtab->tp_diffbuf[idx] == buf)
+      break;
+  return idx;
+}
+
+/*
+ * Find buffer "buf" in the list of diff buffers for tab page "tp".
+ * Return its index or DB_COUNT if not found.
+ */
+static int diff_buf_idx_tp(buf, tp)
+buf_T       *buf;
+tabpage_T   *tp;
+{
+  int idx;
+
+  for (idx = 0; idx < DB_COUNT; ++idx)
+    if (tp->tp_diffbuf[idx] == buf)
+      break;
+  return idx;
+}
+
+/*
+ * Mark the diff info involving buffer "buf" as invalid, it will be updated
+ * when info is requested.
+ */
+void diff_invalidate(buf)
+buf_T       *buf;
+{
+  tabpage_T   *tp;
+  int i;
+
+  for (tp = first_tabpage; tp != NULL; tp = tp->tp_next) {
+    i = diff_buf_idx_tp(buf, tp);
+    if (i != DB_COUNT) {
+      tp->tp_diff_invalid = TRUE;
+      if (tp == curtab)
+        diff_redraw(TRUE);
+    }
+  }
+}
+
+/*
+ * Called by mark_adjust(): update line numbers in "curbuf".
+ */
+void diff_mark_adjust(line1, line2, amount, amount_after)
+linenr_T line1;
+linenr_T line2;
+long amount;
+long amount_after;
+{
+  int idx;
+  tabpage_T   *tp;
+
+  /* Handle all tab pages that use the current buffer in a diff. */
+  for (tp = first_tabpage; tp != NULL; tp = tp->tp_next) {
+    idx = diff_buf_idx_tp(curbuf, tp);
+    if (idx != DB_COUNT)
+      diff_mark_adjust_tp(tp, idx, line1, line2, amount, amount_after);
+  }
+}
+
+/*
+ * Update line numbers in tab page "tp" for "curbuf" with index "idx".
+ * This attempts to update the changes as much as possible:
+ * When inserting/deleting lines outside of existing change blocks, create a
+ * new change block and update the line numbers in following blocks.
+ * When inserting/deleting lines in existing change blocks, update them.
+ */
+static void diff_mark_adjust_tp(tp, idx, line1, line2, amount, amount_after)
+tabpage_T   *tp;
+int idx;
+linenr_T line1;
+linenr_T line2;
+long amount;
+long amount_after;
+{
+  diff_T      *dp;
+  diff_T      *dprev;
+  diff_T      *dnext;
+  int i;
+  int inserted, deleted;
+  int n, off;
+  linenr_T last;
+  linenr_T lnum_deleted = line1;        /* lnum of remaining deletion */
+  int check_unchanged;
+
+  if (line2 == MAXLNUM) {
+    /* mark_adjust(99, MAXLNUM, 9, 0): insert lines */
+    inserted = amount;
+    deleted = 0;
+  } else if (amount_after > 0)   {
+    /* mark_adjust(99, 98, MAXLNUM, 9): a change that inserts lines*/
+    inserted = amount_after;
+    deleted = 0;
+  } else   {
+    /* mark_adjust(98, 99, MAXLNUM, -2): delete lines */
+    inserted = 0;
+    deleted = -amount_after;
+  }
+
+  dprev = NULL;
+  dp = tp->tp_first_diff;
+  for (;; ) {
+    /* If the change is after the previous diff block and before the next
+     * diff block, thus not touching an existing change, create a new diff
+     * block.  Don't do this when ex_diffgetput() is busy. */
+    if ((dp == NULL || dp->df_lnum[idx] - 1 > line2
+         || (line2 == MAXLNUM && dp->df_lnum[idx] > line1))
+        && (dprev == NULL
+            || dprev->df_lnum[idx] + dprev->df_count[idx] < line1)
+        && !diff_busy) {
+      dnext = diff_alloc_new(tp, dprev, dp);
+      if (dnext == NULL)
+        return;
+
+      dnext->df_lnum[idx] = line1;
+      dnext->df_count[idx] = inserted;
+      for (i = 0; i < DB_COUNT; ++i)
+        if (tp->tp_diffbuf[i] != NULL && i != idx) {
+          if (dprev == NULL)
+            dnext->df_lnum[i] = line1;
+          else
+            dnext->df_lnum[i] = line1
+                                + (dprev->df_lnum[i] + dprev->df_count[i])
+                                - (dprev->df_lnum[idx] + dprev->df_count[idx]);
+          dnext->df_count[i] = deleted;
+        }
+    }
+
+    /* if at end of the list, quit */
+    if (dp == NULL)
+      break;
+
+    /*
+     * Check for these situations:
+     *	  1  2	3
+     *	  1  2	3
+     * line1     2	3  4  5
+     *	     2	3  4  5
+     *	     2	3  4  5
+     * line2     2	3  4  5
+     *		3     5  6
+     *		3     5  6
+     */
+    /* compute last line of this change */
+    last = dp->df_lnum[idx] + dp->df_count[idx] - 1;
+
+    /* 1. change completely above line1: nothing to do */
+    if (last >= line1 - 1) {
+      /* 6. change below line2: only adjust for amount_after; also when
+       * "deleted" became zero when deleted all lines between two diffs */
+      if (dp->df_lnum[idx] - (deleted + inserted != 0) > line2) {
+        if (amount_after == 0)
+          break;                /* nothing left to change */
+        dp->df_lnum[idx] += amount_after;
+      } else   {
+        check_unchanged = FALSE;
+
+        /* 2. 3. 4. 5.: inserted/deleted lines touching this diff. */
+        if (deleted > 0) {
+          if (dp->df_lnum[idx] >= line1) {
+            off = dp->df_lnum[idx] - lnum_deleted;
+            if (last <= line2) {
+              /* 4. delete all lines of diff */
+              if (dp->df_next != NULL
+                  && dp->df_next->df_lnum[idx] - 1 <= line2) {
+                /* delete continues in next diff, only do
+                 * lines until that one */
+                n = dp->df_next->df_lnum[idx] - lnum_deleted;
+                deleted -= n;
+                n -= dp->df_count[idx];
+                lnum_deleted = dp->df_next->df_lnum[idx];
+              } else
+                n = deleted - dp->df_count[idx];
+              dp->df_count[idx] = 0;
+            } else   {
+              /* 5. delete lines at or just before top of diff */
+              n = off;
+              dp->df_count[idx] -= line2 - dp->df_lnum[idx] + 1;
+              check_unchanged = TRUE;
+            }
+            dp->df_lnum[idx] = line1;
+          } else   {
+            off = 0;
+            if (last < line2) {
+              /* 2. delete at end of of diff */
+              dp->df_count[idx] -= last - lnum_deleted + 1;
+              if (dp->df_next != NULL
+                  && dp->df_next->df_lnum[idx] - 1 <= line2) {
+                /* delete continues in next diff, only do
+                 * lines until that one */
+                n = dp->df_next->df_lnum[idx] - 1 - last;
+                deleted -= dp->df_next->df_lnum[idx]
+                           - lnum_deleted;
+                lnum_deleted = dp->df_next->df_lnum[idx];
+              } else
+                n = line2 - last;
+              check_unchanged = TRUE;
+            } else   {
+              /* 3. delete lines inside the diff */
+              n = 0;
+              dp->df_count[idx] -= deleted;
+            }
+          }
+
+          for (i = 0; i < DB_COUNT; ++i)
+            if (tp->tp_diffbuf[i] != NULL && i != idx) {
+              dp->df_lnum[i] -= off;
+              dp->df_count[i] += n;
+            }
+        } else   {
+          if (dp->df_lnum[idx] <= line1) {
+            /* inserted lines somewhere in this diff */
+            dp->df_count[idx] += inserted;
+            check_unchanged = TRUE;
+          } else
+            /* inserted lines somewhere above this diff */
+            dp->df_lnum[idx] += inserted;
+        }
+
+        if (check_unchanged)
+          /* Check if inserted lines are equal, may reduce the
+           * size of the diff.  TODO: also check for equal lines
+           * in the middle and perhaps split the block. */
+          diff_check_unchanged(tp, dp);
+      }
+    }
+
+    /* check if this block touches the previous one, may merge them. */
+    if (dprev != NULL && dprev->df_lnum[idx] + dprev->df_count[idx]
+        == dp->df_lnum[idx]) {
+      for (i = 0; i < DB_COUNT; ++i)
+        if (tp->tp_diffbuf[i] != NULL)
+          dprev->df_count[i] += dp->df_count[i];
+      dprev->df_next = dp->df_next;
+      vim_free(dp);
+      dp = dprev->df_next;
+    } else   {
+      /* Advance to next entry. */
+      dprev = dp;
+      dp = dp->df_next;
+    }
+  }
+
+  dprev = NULL;
+  dp = tp->tp_first_diff;
+  while (dp != NULL) {
+    /* All counts are zero, remove this entry. */
+    for (i = 0; i < DB_COUNT; ++i)
+      if (tp->tp_diffbuf[i] != NULL && dp->df_count[i] != 0)
+        break;
+    if (i == DB_COUNT) {
+      dnext = dp->df_next;
+      vim_free(dp);
+      dp = dnext;
+      if (dprev == NULL)
+        tp->tp_first_diff = dnext;
+      else
+        dprev->df_next = dnext;
+    } else   {
+      /* Advance to next entry. */
+      dprev = dp;
+      dp = dp->df_next;
+    }
+
+  }
+
+  if (tp == curtab) {
+    diff_redraw(TRUE);
+
+    /* Need to recompute the scroll binding, may remove or add filler
+     * lines (e.g., when adding lines above w_topline). But it's slow when
+     * making many changes, postpone until redrawing. */
+    diff_need_scrollbind = TRUE;
+  }
+}
+
+/*
+ * Allocate a new diff block and link it between "dprev" and "dp".
+ */
+static diff_T * diff_alloc_new(tp, dprev, dp)
+tabpage_T   *tp;
+diff_T      *dprev;
+diff_T      *dp;
+{
+  diff_T      *dnew;
+
+  dnew = (diff_T *)alloc((unsigned)sizeof(diff_T));
+  if (dnew != NULL) {
+    dnew->df_next = dp;
+    if (dprev == NULL)
+      tp->tp_first_diff = dnew;
+    else
+      dprev->df_next = dnew;
+  }
+  return dnew;
+}
+
+/*
+ * Check if the diff block "dp" can be made smaller for lines at the start and
+ * end that are equal.  Called after inserting lines.
+ * This may result in a change where all buffers have zero lines, the caller
+ * must take care of removing it.
+ */
+static void diff_check_unchanged(tp, dp)
+tabpage_T   *tp;
+diff_T      *dp;
+{
+  int i_org;
+  int i_new;
+  int off_org, off_new;
+  char_u      *line_org;
+  int dir = FORWARD;
+
+  /* Find the first buffers, use it as the original, compare the other
+   * buffer lines against this one. */
+  for (i_org = 0; i_org < DB_COUNT; ++i_org)
+    if (tp->tp_diffbuf[i_org] != NULL)
+      break;
+  if (i_org == DB_COUNT)        /* safety check */
+    return;
+
+  if (diff_check_sanity(tp, dp) == FAIL)
+    return;
+
+  /* First check lines at the top, then at the bottom. */
+  off_org = 0;
+  off_new = 0;
+  for (;; ) {
+    /* Repeat until a line is found which is different or the number of
+     * lines has become zero. */
+    while (dp->df_count[i_org] > 0) {
+      /* Copy the line, the next ml_get() will invalidate it.  */
+      if (dir == BACKWARD)
+        off_org = dp->df_count[i_org] - 1;
+      line_org = vim_strsave(ml_get_buf(tp->tp_diffbuf[i_org],
+              dp->df_lnum[i_org] + off_org, FALSE));
+      if (line_org == NULL)
+        return;
+      for (i_new = i_org + 1; i_new < DB_COUNT; ++i_new) {
+        if (tp->tp_diffbuf[i_new] == NULL)
+          continue;
+        if (dir == BACKWARD)
+          off_new = dp->df_count[i_new] - 1;
+        /* if other buffer doesn't have this line, it was inserted */
+        if (off_new < 0 || off_new >= dp->df_count[i_new])
+          break;
+        if (diff_cmp(line_org, ml_get_buf(tp->tp_diffbuf[i_new],
+                    dp->df_lnum[i_new] + off_new, FALSE)) != 0)
+          break;
+      }
+      vim_free(line_org);
+
+      /* Stop when a line isn't equal in all diff buffers. */
+      if (i_new != DB_COUNT)
+        break;
+
+      /* Line matched in all buffers, remove it from the diff. */
+      for (i_new = i_org; i_new < DB_COUNT; ++i_new)
+        if (tp->tp_diffbuf[i_new] != NULL) {
+          if (dir == FORWARD)
+            ++dp->df_lnum[i_new];
+          --dp->df_count[i_new];
+        }
+    }
+    if (dir == BACKWARD)
+      break;
+    dir = BACKWARD;
+  }
+}
+
+/*
+ * Check if a diff block doesn't contain invalid line numbers.
+ * This can happen when the diff program returns invalid results.
+ */
+static int diff_check_sanity(tp, dp)
+tabpage_T   *tp;
+diff_T      *dp;
+{
+  int i;
+
+  for (i = 0; i < DB_COUNT; ++i)
+    if (tp->tp_diffbuf[i] != NULL)
+      if (dp->df_lnum[i] + dp->df_count[i] - 1
+          > tp->tp_diffbuf[i]->b_ml.ml_line_count)
+        return FAIL;
+  return OK;
+}
+
+/*
+ * Mark all diff buffers in the current tab page for redraw.
+ */
+static void diff_redraw(dofold)
+int dofold;                 /* also recompute the folds */
+{
+  win_T       *wp;
+  int n;
+
+  for (wp = firstwin; wp != NULL; wp = wp->w_next)
+    if (wp->w_p_diff) {
+      redraw_win_later(wp, SOME_VALID);
+      if (dofold && foldmethodIsDiff(wp))
+        foldUpdateAll(wp);
+      /* A change may have made filler lines invalid, need to take care
+       * of that for other windows. */
+      n = diff_check(wp, wp->w_topline);
+      if ((wp != curwin && wp->w_topfill > 0) || n > 0) {
+        if (wp->w_topfill > n)
+          wp->w_topfill = (n < 0 ? 0 : n);
+        else if (n > 0 && n > wp->w_topfill)
+          wp->w_topfill = n;
+      }
+    }
+}
+
+/*
+ * Write buffer "buf" to file "name".
+ * Always use 'fileformat' set to "unix".
+ * Return FAIL for failure
+ */
+static int diff_write(buf, fname)
+buf_T       *buf;
+char_u      *fname;
+{
+  int r;
+  char_u      *save_ff;
+
+  save_ff = buf->b_p_ff;
+  buf->b_p_ff = vim_strsave((char_u *)FF_UNIX);
+  r = buf_write(buf, fname, NULL, (linenr_T)1, buf->b_ml.ml_line_count,
+      NULL, FALSE, FALSE, FALSE, TRUE);
+  free_string_option(buf->b_p_ff);
+  buf->b_p_ff = save_ff;
+  return r;
+}
+
+/*
+ * Completely update the diffs for the buffers involved.
+ * This uses the ordinary "diff" command.
+ * The buffers are written to a file, also for unmodified buffers (the file
+ * could have been produced by autocommands, e.g. the netrw plugin).
+ */
+void ex_diffupdate(eap)
+exarg_T     *eap UNUSED;            /* can be NULL */
+{
+  buf_T       *buf;
+  int idx_orig;
+  int idx_new;
+  char_u      *tmp_orig;
+  char_u      *tmp_new;
+  char_u      *tmp_diff;
+  FILE        *fd;
+  int ok;
+  int io_error = FALSE;
+
+  /* Delete all diffblocks. */
+  diff_clear(curtab);
+  curtab->tp_diff_invalid = FALSE;
+
+  /* Use the first buffer as the original text. */
+  for (idx_orig = 0; idx_orig < DB_COUNT; ++idx_orig)
+    if (curtab->tp_diffbuf[idx_orig] != NULL)
+      break;
+  if (idx_orig == DB_COUNT)
+    return;
+
+  /* Only need to do something when there is another buffer. */
+  for (idx_new = idx_orig + 1; idx_new < DB_COUNT; ++idx_new)
+    if (curtab->tp_diffbuf[idx_new] != NULL)
+      break;
+  if (idx_new == DB_COUNT)
+    return;
+
+  /* We need three temp file names. */
+  tmp_orig = vim_tempname('o');
+  tmp_new = vim_tempname('n');
+  tmp_diff = vim_tempname('d');
+  if (tmp_orig == NULL || tmp_new == NULL || tmp_diff == NULL)
+    goto theend;
+
+  /*
+   * Do a quick test if "diff" really works.  Otherwise it looks like there
+   * are no differences.  Can't use the return value, it's non-zero when
+   * there are differences.
+   * May try twice, first with "-a" and then without.
+   */
+  for (;; ) {
+    ok = FALSE;
+    fd = mch_fopen((char *)tmp_orig, "w");
+    if (fd == NULL)
+      io_error = TRUE;
+    else {
+      if (fwrite("line1\n", (size_t)6, (size_t)1, fd) != 1)
+        io_error = TRUE;
+      fclose(fd);
+      fd = mch_fopen((char *)tmp_new, "w");
+      if (fd == NULL)
+        io_error = TRUE;
+      else {
+        if (fwrite("line2\n", (size_t)6, (size_t)1, fd) != 1)
+          io_error = TRUE;
+        fclose(fd);
+        diff_file(tmp_orig, tmp_new, tmp_diff);
+        fd = mch_fopen((char *)tmp_diff, "r");
+        if (fd == NULL)
+          io_error = TRUE;
+        else {
+          char_u linebuf[LBUFLEN];
+
+          for (;; ) {
+            /* There must be a line that contains "1c1". */
+            if (tag_fgets(linebuf, LBUFLEN, fd))
+              break;
+            if (STRNCMP(linebuf, "1c1", 3) == 0)
+              ok = TRUE;
+          }
+          fclose(fd);
+        }
+        mch_remove(tmp_diff);
+        mch_remove(tmp_new);
+      }
+      mch_remove(tmp_orig);
+    }
+
+    /* When using 'diffexpr' break here. */
+    if (*p_dex != NUL)
+      break;
+
+
+    /* If we checked if "-a" works already, break here. */
+    if (diff_a_works != MAYBE)
+      break;
+    diff_a_works = ok;
+
+    /* If "-a" works break here, otherwise retry without "-a". */
+    if (ok)
+      break;
+  }
+  if (!ok) {
+    if (io_error)
+      EMSG(_("E810: Cannot read or write temp files"));
+    EMSG(_("E97: Cannot create diffs"));
+    diff_a_works = MAYBE;
+    goto theend;
+  }
+
+  /* :diffupdate! */
+  if (eap != NULL && eap->forceit)
+    for (idx_new = idx_orig; idx_new < DB_COUNT; ++idx_new) {
+      buf = curtab->tp_diffbuf[idx_new];
+      if (buf_valid(buf))
+        buf_check_timestamp(buf, FALSE);
+    }
+
+  /* Write the first buffer to a tempfile. */
+  buf = curtab->tp_diffbuf[idx_orig];
+  if (diff_write(buf, tmp_orig) == FAIL)
+    goto theend;
+
+  /* Make a difference between the first buffer and every other. */
+  for (idx_new = idx_orig + 1; idx_new < DB_COUNT; ++idx_new) {
+    buf = curtab->tp_diffbuf[idx_new];
+    if (buf == NULL)
+      continue;
+    if (diff_write(buf, tmp_new) == FAIL)
+      continue;
+    diff_file(tmp_orig, tmp_new, tmp_diff);
+
+    /* Read the diff output and add each entry to the diff list. */
+    diff_read(idx_orig, idx_new, tmp_diff);
+    mch_remove(tmp_diff);
+    mch_remove(tmp_new);
+  }
+  mch_remove(tmp_orig);
+
+  /* force updating cursor position on screen */
+  curwin->w_valid_cursor.lnum = 0;
+
+  diff_redraw(TRUE);
+
+theend:
+  vim_free(tmp_orig);
+  vim_free(tmp_new);
+  vim_free(tmp_diff);
+}
+
+/*
+ * Make a diff between files "tmp_orig" and "tmp_new", results in "tmp_diff".
+ */
+static void diff_file(tmp_orig, tmp_new, tmp_diff)
+char_u      *tmp_orig;
+char_u      *tmp_new;
+char_u      *tmp_diff;
+{
+  char_u      *cmd;
+  size_t len;
+
+  if (*p_dex != NUL)
+    /* Use 'diffexpr' to generate the diff file. */
+    eval_diff(tmp_orig, tmp_new, tmp_diff);
+  else {
+    len = STRLEN(tmp_orig) + STRLEN(tmp_new)
+          + STRLEN(tmp_diff) + STRLEN(p_srr) + 27;
+    cmd = alloc((unsigned)len);
+    if (cmd != NULL) {
+      /* We don't want $DIFF_OPTIONS to get in the way. */
+      if (getenv("DIFF_OPTIONS"))
+        vim_setenv((char_u *)"DIFF_OPTIONS", (char_u *)"");
+
+      /* Build the diff command and execute it.  Always use -a, binary
+       * differences are of no use.  Ignore errors, diff returns
+       * non-zero when differences have been found. */
+      vim_snprintf((char *)cmd, len, "diff %s%s%s%s%s %s",
+          diff_a_works == FALSE ? "" : "-a ",
+          "",
+          (diff_flags & DIFF_IWHITE) ? "-b " : "",
+          (diff_flags & DIFF_ICASE) ? "-i " : "",
+          tmp_orig, tmp_new);
+      append_redir(cmd, (int)len, p_srr, tmp_diff);
+      block_autocmds();         /* Avoid ShellCmdPost stuff */
+      (void)call_shell(cmd, SHELL_FILTER|SHELL_SILENT|SHELL_DOOUT);
+      unblock_autocmds();
+      vim_free(cmd);
+    }
+  }
+}
+
+/*
+ * Create a new version of a file from the current buffer and a diff file.
+ * The buffer is written to a file, also for unmodified buffers (the file
+ * could have been produced by autocommands, e.g. the netrw plugin).
+ */
+void ex_diffpatch(eap)
+exarg_T     *eap;
+{
+  char_u      *tmp_orig;        /* name of original temp file */
+  char_u      *tmp_new;         /* name of patched temp file */
+  char_u      *buf = NULL;
+  size_t buflen;
+  win_T       *old_curwin = curwin;
+  char_u      *newname = NULL;          /* name of patched file buffer */
+#ifdef UNIX
+  char_u dirbuf[MAXPATHL];
+  char_u      *fullname = NULL;
+#endif
+  struct stat st;
+
+
+  /* We need two temp file names. */
+  tmp_orig = vim_tempname('o');
+  tmp_new = vim_tempname('n');
+  if (tmp_orig == NULL || tmp_new == NULL)
+    goto theend;
+
+  /* Write the current buffer to "tmp_orig". */
+  if (buf_write(curbuf, tmp_orig, NULL,
+          (linenr_T)1, curbuf->b_ml.ml_line_count,
+          NULL, FALSE, FALSE, FALSE, TRUE) == FAIL)
+    goto theend;
+
+#ifdef UNIX
+  /* Get the absolute path of the patchfile, changing directory below. */
+  fullname = FullName_save(eap->arg, FALSE);
+#endif
+  buflen = STRLEN(tmp_orig) + (
+# ifdef UNIX
+    fullname != NULL ? STRLEN(fullname) :
+# endif
+    STRLEN(eap->arg)) + STRLEN(tmp_new) + 16;
+  buf = alloc((unsigned)buflen);
+  if (buf == NULL)
+    goto theend;
+
+#ifdef UNIX
+  /* Temporarily chdir to /tmp, to avoid patching files in the current
+   * directory when the patch file contains more than one patch.  When we
+   * have our own temp dir use that instead, it will be cleaned up when we
+   * exit (any .rej files created).  Don't change directory if we can't
+   * return to the current. */
+  if (mch_dirname(dirbuf, MAXPATHL) != OK || mch_chdir((char *)dirbuf) != 0)
+    dirbuf[0] = NUL;
+  else {
+# ifdef TEMPDIRNAMES
+    if (vim_tempdir != NULL)
+      ignored = mch_chdir((char *)vim_tempdir);
+    else
+# endif
+    ignored = mch_chdir("/tmp");
+    shorten_fnames(TRUE);
+  }
+#endif
+
+  if (*p_pex != NUL)
+    /* Use 'patchexpr' to generate the new file. */
+    eval_patch(tmp_orig,
+# ifdef UNIX
+        fullname != NULL ? fullname :
+# endif
+        eap->arg, tmp_new);
+  else {
+    /* Build the patch command and execute it.  Ignore errors.  Switch to
+     * cooked mode to allow the user to respond to prompts. */
+    vim_snprintf((char *)buf, buflen, "patch -o %s %s < \"%s\"",
+        tmp_new, tmp_orig,
+# ifdef UNIX
+        fullname != NULL ? fullname :
+# endif
+        eap->arg);
+    block_autocmds();           /* Avoid ShellCmdPost stuff */
+    (void)call_shell(buf, SHELL_FILTER | SHELL_COOKED);
+    unblock_autocmds();
+  }
+
+#ifdef UNIX
+  if (dirbuf[0] != NUL) {
+    if (mch_chdir((char *)dirbuf) != 0)
+      EMSG(_(e_prev_dir));
+    shorten_fnames(TRUE);
+  }
+#endif
+
+  /* patch probably has written over the screen */
+  redraw_later(CLEAR);
+
+  /* Delete any .orig or .rej file created. */
+  STRCPY(buf, tmp_new);
+  STRCAT(buf, ".orig");
+  mch_remove(buf);
+  STRCPY(buf, tmp_new);
+  STRCAT(buf, ".rej");
+  mch_remove(buf);
+
+  /* Only continue if the output file was created. */
+  if (mch_stat((char *)tmp_new, &st) < 0 || st.st_size == 0)
+    EMSG(_("E816: Cannot read patch output"));
+  else {
+    if (curbuf->b_fname != NULL) {
+      newname = vim_strnsave(curbuf->b_fname,
+          (int)(STRLEN(curbuf->b_fname) + 4));
+      if (newname != NULL)
+        STRCAT(newname, ".new");
+    }
+
+    /* don't use a new tab page, each tab page has its own diffs */
+    cmdmod.tab = 0;
+
+    if (win_split(0, (diff_flags & DIFF_VERTICAL) ? WSP_VERT : 0) != FAIL) {
+      /* Pretend it was a ":split fname" command */
+      eap->cmdidx = CMD_split;
+      eap->arg = tmp_new;
+      do_exedit(eap, old_curwin);
+
+      /* check that split worked and editing tmp_new */
+      if (curwin != old_curwin && win_valid(old_curwin)) {
+        /* Set 'diff', 'scrollbind' on and 'wrap' off. */
+        diff_win_options(curwin, TRUE);
+        diff_win_options(old_curwin, TRUE);
+
+        if (newname != NULL) {
+          /* do a ":file filename.new" on the patched buffer */
+          eap->arg = newname;
+          ex_file(eap);
+
+          /* Do filetype detection with the new name. */
+          if (au_has_group((char_u *)"filetypedetect"))
+            do_cmdline_cmd((char_u *)":doau filetypedetect BufRead");
+        }
+      }
+    }
+  }
+
+theend:
+  if (tmp_orig != NULL)
+    mch_remove(tmp_orig);
+  vim_free(tmp_orig);
+  if (tmp_new != NULL)
+    mch_remove(tmp_new);
+  vim_free(tmp_new);
+  vim_free(newname);
+  vim_free(buf);
+#ifdef UNIX
+  vim_free(fullname);
+#endif
+}
+
+/*
+ * Split the window and edit another file, setting options to show the diffs.
+ */
+void ex_diffsplit(eap)
+exarg_T     *eap;
+{
+  win_T       *old_curwin = curwin;
+
+  /* don't use a new tab page, each tab page has its own diffs */
+  cmdmod.tab = 0;
+
+  if (win_split(0, (diff_flags & DIFF_VERTICAL) ? WSP_VERT : 0) != FAIL) {
+    /* Pretend it was a ":split fname" command */
+    eap->cmdidx = CMD_split;
+    curwin->w_p_diff = TRUE;
+    do_exedit(eap, old_curwin);
+
+    if (curwin != old_curwin) {                 /* split must have worked */
+      /* Set 'diff', 'scrollbind' on and 'wrap' off. */
+      diff_win_options(curwin, TRUE);
+      diff_win_options(old_curwin, TRUE);
+    }
+  }
+}
+
+/*
+ * Set options to show diffs for the current window.
+ */
+void ex_diffthis(eap)
+exarg_T     *eap UNUSED;
+{
+  /* Set 'diff', 'scrollbind' on and 'wrap' off. */
+  diff_win_options(curwin, TRUE);
+}
+
+/*
+ * Set options in window "wp" for diff mode.
+ */
+void diff_win_options(wp, addbuf)
+win_T       *wp;
+int addbuf;                     /* Add buffer to diff. */
+{
+  win_T *old_curwin = curwin;
+
+  /* close the manually opened folds */
+  curwin = wp;
+  newFoldLevel();
+  curwin = old_curwin;
+
+  wp->w_p_diff = TRUE;
+
+  /* Use 'scrollbind' and 'cursorbind' when available */
+  if (!wp->w_p_diff_saved)
+    wp->w_p_scb_save = wp->w_p_scb;
+  wp->w_p_scb = TRUE;
+  if (!wp->w_p_diff_saved)
+    wp->w_p_crb_save = wp->w_p_crb;
+  wp->w_p_crb = TRUE;
+  if (!wp->w_p_diff_saved)
+    wp->w_p_wrap_save = wp->w_p_wrap;
+  wp->w_p_wrap = FALSE;
+  curwin = wp;
+  curbuf = curwin->w_buffer;
+  if (!wp->w_p_diff_saved)
+    wp->w_p_fdm_save = vim_strsave(wp->w_p_fdm);
+  set_string_option_direct((char_u *)"fdm", -1, (char_u *)"diff",
+      OPT_LOCAL|OPT_FREE, 0);
+  curwin = old_curwin;
+  curbuf = curwin->w_buffer;
+  if (!wp->w_p_diff_saved) {
+    wp->w_p_fdc_save = wp->w_p_fdc;
+    wp->w_p_fen_save = wp->w_p_fen;
+    wp->w_p_fdl_save = wp->w_p_fdl;
+  }
+  wp->w_p_fdc = diff_foldcolumn;
+  wp->w_p_fen = TRUE;
+  wp->w_p_fdl = 0;
+  foldUpdateAll(wp);
+  /* make sure topline is not halfway a fold */
+  changed_window_setting_win(wp);
+  if (vim_strchr(p_sbo, 'h') == NULL)
+    do_cmdline_cmd((char_u *)"set sbo+=hor");
+  /* Saved the current values, to be restored in ex_diffoff(). */
+  wp->w_p_diff_saved = TRUE;
+
+  if (addbuf)
+    diff_buf_add(wp->w_buffer);
+  redraw_win_later(wp, NOT_VALID);
+}
+
+/*
+ * Set options not to show diffs.  For the current window or all windows.
+ * Only in the current tab page.
+ */
+void ex_diffoff(eap)
+exarg_T     *eap;
+{
+  win_T       *wp;
+  win_T       *old_curwin = curwin;
+  int diffwin = FALSE;
+
+  for (wp = firstwin; wp != NULL; wp = wp->w_next) {
+    if (eap->forceit ? wp->w_p_diff : wp == curwin) {
+      /* Set 'diff', 'scrollbind' off and 'wrap' on. If option values
+       * were saved in diff_win_options() restore them. */
+      wp->w_p_diff = FALSE;
+
+      if (wp->w_p_scb)
+        wp->w_p_scb = wp->w_p_diff_saved ? wp->w_p_scb_save : FALSE;
+      if (wp->w_p_crb)
+        wp->w_p_crb = wp->w_p_diff_saved ? wp->w_p_crb_save : FALSE;
+      if (!wp->w_p_wrap)
+        wp->w_p_wrap = wp->w_p_diff_saved ? wp->w_p_wrap_save : TRUE;
+      curwin = wp;
+      curbuf = curwin->w_buffer;
+      if (wp->w_p_diff_saved) {
+        free_string_option(wp->w_p_fdm);
+        wp->w_p_fdm = wp->w_p_fdm_save;
+        wp->w_p_fdm_save = empty_option;
+      } else
+        set_string_option_direct((char_u *)"fdm", -1,
+            (char_u *)"manual", OPT_LOCAL|OPT_FREE, 0);
+      curwin = old_curwin;
+      curbuf = curwin->w_buffer;
+      if (wp->w_p_fdc == diff_foldcolumn)
+        wp->w_p_fdc = wp->w_p_diff_saved ? wp->w_p_fdc_save : 0;
+      if (wp->w_p_fdl == 0 && wp->w_p_diff_saved)
+        wp->w_p_fdl = wp->w_p_fdl_save;
+
+      if (wp->w_p_fen) {
+        /* Only restore 'foldenable' when 'foldmethod' is not
+         * "manual", otherwise we continue to show the diff folds. */
+        if (foldmethodIsManual(wp) || !wp->w_p_diff_saved)
+          wp->w_p_fen = FALSE;
+        else
+          wp->w_p_fen = wp->w_p_fen_save;
+      }
+
+      foldUpdateAll(wp);
+      /* make sure topline is not halfway a fold */
+      changed_window_setting_win(wp);
+      /* Note: 'sbo' is not restored, it's a global option. */
+      diff_buf_adjust(wp);
+
+      wp->w_p_diff_saved = FALSE;
+    }
+    diffwin |= wp->w_p_diff;
+  }
+
+  /* Remove "hor" from from 'scrollopt' if there are no diff windows left. */
+  if (!diffwin && vim_strchr(p_sbo, 'h') != NULL)
+    do_cmdline_cmd((char_u *)"set sbo-=hor");
+}
+
+/*
+ * Read the diff output and add each entry to the diff list.
+ */
+static void diff_read(idx_orig, idx_new, fname)
+int idx_orig;                   /* idx of original file */
+int idx_new;                    /* idx of new file */
+char_u      *fname;             /* name of diff output file */
+{
+  FILE        *fd;
+  diff_T      *dprev = NULL;
+  di