thread.c

mutt-1.5.12 源代码。linux 下邮件接受的工具。

/*
 * Copyright (C) 1996-2002 Michael R. Elkins <[e-mail]>
 *
 *     This program is free software; you can redistribute it and/or modify
 *     it under the terms of the GNU General Public License as published by
 *     the Free Software Foundation; either version 2 of the License, or
 *     (at your option) any later version.
 * 
 *     This program is distributed in the hope that it will be useful,
 *     but WITHOUT ANY WARRANTY; without even the implied warranty of
 *     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *     GNU General Public License for more details.
 * 
 *     You should have received a copy of the GNU General Public License
 *     along with this program; if not, write to the Free Software
 *     Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */ 

#if HAVE_CONFIG_H
# include "config.h"
#endif

#include "mutt.h"
#include "sort.h"

#include <string.h>
#include <ctype.h>

#define VISIBLE(hdr, ctx) (hdr->virtual >= 0 || (hdr->collapsed && (!ctx->pattern || hdr->limited)))

/* determine whether a is a descendant of b */
static int is_descendant (THREAD *a, THREAD *b)
{
  while (a)
  {
    if (a == b)
      return (1);
    a = a->parent;
  }
  return (0);
}

/* Determines whether to display a message's subject. */
static int need_display_subject (CONTEXT *ctx, HEADER *hdr)
{
  THREAD *tmp, *tree = hdr->thread;

  /* if the user disabled subject hiding, display it */
  if (!option (OPTHIDETHREADSUBJECT))
    return (1);

  /* if our subject is different from our parent's, display it */
  if (hdr->subject_changed)
    return (1);

  /* if our subject is different from that of our closest previously displayed
   * sibling, display the subject */
  for (tmp = tree->prev; tmp; tmp = tmp->prev)
  {
    hdr = tmp->message;
    if (hdr && VISIBLE (hdr, ctx))
    {
      if (hdr->subject_changed)
	return (1);
      else
	break;
    }
  }
  
  /* if there is a parent-to-child subject change anywhere between us and our
   * closest displayed ancestor, display the subject */
  for (tmp = tree->parent; tmp; tmp = tmp->parent)
  {
    hdr = tmp->message;
    if (hdr)
    {
      if (VISIBLE (hdr, ctx))
	return (0);
      else if (hdr->subject_changed)
	return (1);
    }
  }

  /* if we have no visible parent or previous sibling, display the subject */
  return (1);
}

static void linearize_tree (CONTEXT *ctx)
{
  THREAD *tree = ctx->tree;
  HEADER **array = ctx->hdrs + (Sort & SORT_REVERSE ? ctx->msgcount - 1 : 0);

  while (tree)
  {
    while (!tree->message)
      tree = tree->child;

    *array = tree->message;
    array += Sort & SORT_REVERSE ? -1 : 1;

    if (tree->child)
      tree = tree->child;
    else
    {
      while (tree)
      {
	if (tree->next)
	{
	  tree = tree->next;
	  break;
	}
	else
	  tree = tree->parent;
      }
    }
  }
}

/* this calculates whether a node is the root of a subtree that has visible
 * nodes, whether a node itself is visible, whether, if invisible, it has
 * depth anyway, and whether any of its later siblings are roots of visible
 * subtrees.  while it's at it, it frees the old thread display, so we can
 * skip parts of the tree in mutt_draw_tree() if we've decided here that we
 * don't care about them any more.
 */
static void calculate_visibility (CONTEXT *ctx, int *max_depth)
{
  THREAD *tmp, *tree = ctx->tree;
  int hide_top_missing = option (OPTHIDETOPMISSING) && !option (OPTHIDEMISSING);
  int hide_top_limited = option (OPTHIDETOPLIMITED) && !option (OPTHIDELIMITED);
  int depth = 0;

  /* we walk each level backwards to make it easier to compute next_subtree_visible */
  while (tree->next)
    tree = tree->next;
  *max_depth = 0;

  FOREVER
  {
    if (depth > *max_depth)
      *max_depth = depth;

    tree->subtree_visible = 0;
    if (tree->message)
    {
      FREE (&tree->message->tree);
      if (VISIBLE (tree->message, ctx))
      {
	tree->deep = 1;
	tree->visible = 1;
	tree->message->display_subject = need_display_subject (ctx, tree->message);
	for (tmp = tree; tmp; tmp = tmp->parent)
	{
	  if (tmp->subtree_visible)
	  {
	    tmp->deep = 1;
	    tmp->subtree_visible = 2;
	    break;
	  }
	  else
	    tmp->subtree_visible = 1;
	}
      }
      else
      {
	tree->visible = 0;
	tree->deep = !option (OPTHIDELIMITED);
      }
    }
    else
    {
      tree->visible = 0;
      tree->deep = !option (OPTHIDEMISSING);
    }
    tree->next_subtree_visible = tree->next && (tree->next->next_subtree_visible
						|| tree->next->subtree_visible);
    if (tree->child)
    {
      depth++;
      tree = tree->child;
      while (tree->next)
	tree = tree->next;
    }
    else if (tree->prev)
      tree = tree->prev;
    else
    {
      while (tree && !tree->prev)
      {
	depth--;
	tree = tree->parent;
      }
      if (!tree)
	break;
      else
	tree = tree->prev;
    }
  }
  
  /* now fix up for the OPTHIDETOP* options if necessary */
  if (hide_top_limited || hide_top_missing)
  {
    tree = ctx->tree;
    FOREVER
    {
      if (!tree->visible && tree->deep && tree->subtree_visible < 2 
	  && ((tree->message && hide_top_limited) || (!tree->message && hide_top_missing)))
	tree->deep = 0;
      if (!tree->deep && tree->child && tree->subtree_visible)
	tree = tree->child;
      else if (tree->next)
	tree = tree->next;
      else
      {
	while (tree && !tree->next)
	  tree = tree->parent;
	if (!tree)
	  break;
	else
	  tree = tree->next;
      }
    }
  }
}

/* Since the graphics characters have a value >255, I have to resort to
 * using escape sequences to pass the information to print_enriched_string().
 * These are the macros M_TREE_* defined in mutt.h.
 *
 * ncurses should automatically use the default ASCII characters instead of
 * graphics chars on terminals which don't support them (see the man page
 * for curs_addch).
 */
void mutt_draw_tree (CONTEXT *ctx)
{
  char *pfx = NULL, *mypfx = NULL, *arrow = NULL, *myarrow = NULL, *new_tree;
  char corner = (Sort & SORT_REVERSE) ? M_TREE_ULCORNER : M_TREE_LLCORNER;
  char vtee = (Sort & SORT_REVERSE) ? M_TREE_BTEE : M_TREE_TTEE;
  int depth = 0, start_depth = 0, max_depth = 0, width = option (OPTNARROWTREE) ? 1 : 2;
  THREAD *nextdisp = NULL, *pseudo = NULL, *parent = NULL, *tree = ctx->tree;

  /* Do the visibility calculations and free the old thread chars.
   * From now on we can simply ignore invisible subtrees
   */
  calculate_visibility (ctx, &max_depth);
  pfx = safe_malloc (width * max_depth + 2);
  arrow = safe_malloc (width * max_depth + 2);
  while (tree)
  {
    if (depth)
    {
      myarrow = arrow + (depth - start_depth - (start_depth ? 0 : 1)) * width;
      if (depth && start_depth == depth)
	myarrow[0] = nextdisp ? M_TREE_LTEE : corner;
      else if (parent->message && !option (OPTHIDELIMITED))
	myarrow[0] = M_TREE_HIDDEN;
      else if (!parent->message && !option (OPTHIDEMISSING))
	myarrow[0] = M_TREE_MISSING;
      else
	myarrow[0] = vtee;
      if (width == 2)
	myarrow[1] = pseudo ?  M_TREE_STAR
	                     : (tree->duplicate_thread ? M_TREE_EQUALS : M_TREE_HLINE);
      if (tree->visible)
      {
	myarrow[width] = M_TREE_RARROW;
	myarrow[width + 1] = 0;
	new_tree = safe_malloc ((2 + depth * width));
	if (start_depth > 1)
	{
	  strncpy (new_tree, pfx, (start_depth - 1) * width);
	  strfcpy (new_tree + (start_depth - 1) * width,
		   arrow, (1 + depth - start_depth) * width + 2);
	}
	else
	  strfcpy (new_tree, arrow, 2 + depth * width);
	tree->message->tree = new_tree;
      }
    }
    if (tree->child && depth)
    {
      mypfx = pfx + (depth - 1) * width;
      mypfx[0] = nextdisp ? M_TREE_VLINE : M_TREE_SPACE;
      if (width == 2)
	mypfx[1] = M_TREE_SPACE;
    }
    parent = tree;
    nextdisp = NULL;
    pseudo = NULL;
    do
    {
      if (tree->child && tree->subtree_visible)
      {
	if (tree->deep)
	  depth++;
	if (tree->visible)
	  start_depth = depth;
	tree = tree->child;

	/* we do this here because we need to make sure that the first child thread
	 * of the old tree that we deal with is actually displayed if any are,
	 * or we might set the parent variable wrong while going through it. */
	while (!tree->subtree_visible && tree->next)
	  tree = tree->next;
      }
      else
      {
	while (!tree->next && tree->parent)
	{
	  if (tree == pseudo)
	    pseudo = NULL;
	  if (tree == nextdisp)
	    nextdisp = NULL;
	  if (tree->visible)
	    start_depth = depth;
	  tree = tree->parent;
	  if (tree->deep)
	  {
	    if (start_depth == depth)
	      start_depth--;
	    depth--;
	  }
	}
	if (tree == pseudo)
	  pseudo = NULL;
	if (tree == nextdisp)
	  nextdisp = NULL;
	if (tree->visible)
	  start_depth = depth;
	tree = tree->next;
	if (!tree)
	  break;
      }
      if (!pseudo && tree->fake_thread)
	pseudo = tree;
      if (!nextdisp && tree->next_subtree_visible)
	nextdisp = tree;
    }
    while (!tree->deep);
  }

  FREE (&pfx);
  FREE (&arrow);
}

/* since we may be trying to attach as a pseudo-thread a THREAD that
 * has no message, we have to make a list of all the subjects of its
 * most immediate existing descendants.  we also note the earliest
 * date on any of the parents and put it in *dateptr. */
static LIST *make_subject_list (THREAD *cur, time_t *dateptr)
{
  THREAD *start = cur;
  ENVELOPE *env;
  time_t thisdate;
  LIST *curlist, *oldlist, *newlist, *subjects = NULL;
  int rc = 0;
  
  FOREVER
  {
    while (!cur->message)
      cur = cur->child;

    if (dateptr)
    {
      thisdate = option (OPTTHREADRECEIVED)
	? cur->message->received : cur->message->date_sent;
      if (!*dateptr || thisdate < *dateptr)
	*dateptr = thisdate;
    }

    env = cur->message->env;
    if (env->real_subj &&
	((env->real_subj != env->subject) || (!option (OPTSORTRE))))
    {
      for (curlist = subjects, oldlist = NULL;
	   curlist; oldlist = curlist, curlist = curlist->next)
      {
	rc = mutt_strcmp (env->real_subj, curlist->data);
	if (rc >= 0)
	  break;
      }
      if (!curlist || rc > 0)
      {
	newlist = safe_calloc (1, sizeof (LIST));
	newlist->data = env->real_subj;
	if (oldlist)
	{
	  newlist->next = oldlist->next;
	  oldlist->next = newlist;
	}
	else
	{
	  newlist->next = subjects;
	  subjects = newlist;
	}
      }
    }

    while (!cur->next && cur != start)
    {
      cur = cur->parent;
    }
    if (cur == start)
      break;
    cur = cur->next;
  }

  return (subjects);
}

/* find the best possible match for a parent mesage based upon subject.
 * if there are multiple matches, the one which was sent the latest, but
 * before the current message, is used. 
 */
static THREAD *find_subject (CONTEXT *ctx, THREAD *cur)
{
  struct hash_elem *ptr;
  THREAD *tmp, *last = NULL;
  int hash;
  LIST *subjects = NULL, *oldlist;
  time_t date = 0;  

  subjects = make_subject_list (cur, &date);

  while (subjects)
  {
    hash = hash_string ((unsigned char *) subjects->data,
			ctx->subj_hash->nelem);
    for (ptr = ctx->subj_hash->table[hash]; ptr; ptr = ptr->next)
    {
      tmp = ((HEADER *) ptr->data)->thread;
      if (tmp != cur &&			   /* don't match the same message */
	  !tmp->fake_thread &&		   /* don't match pseudo threads */
	  tmp->message->subject_changed && /* only match interesting replies */
	  !is_descendant (tmp, cur) &&	   /* don't match in the same thread */
	  (date >= (option (OPTTHREADRECEIVED) ?
		    tmp->message->received :
		    tmp->message->date_sent)) &&
	  (!last ||
	   (option (OPTTHREADRECEIVED) ?
	    (last->message->received < tmp->message->received) :
	    (last->message->date_sent < tmp->message->date_sent))) &&
	  tmp->message->env->real_subj &&
	  mutt_strcmp (subjects->data, tmp->message->env->real_subj) == 0)
	last = tmp; /* best match so far */
    }

    oldlist = subjects;
    subjects = subjects->next;
    FREE (&oldlist);
  }
  return (last);
}

/* remove cur and its descendants from their current location.
 * also make sure ancestors of cur no longer are sorted by the
 * fact that cur is their descendant. */
static void unlink_message (THREAD **old, THREAD *cur)
{
  THREAD *tmp;

  if (cur->prev)
    cur->prev->next = cur->next;
  else
    *old = cur->next;

  if (cur->next)
    cur->next->prev = cur->prev;

  if (cur->sort_key)
  {
    for (tmp = cur->parent; tmp && tmp->sort_key == cur->sort_key;
	 tmp = tmp->parent)
      tmp->sort_key = NULL;
  }