To: vim_dev@googlegroups.com
Subject: Patch 7.4.1827
Fcc: outbox
From: Bram Moolenaar <Bram@moolenaar.net>
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------------

Patch 7.4.1827
Problem:    No error when invoking a callback when it's not safe.
Solution:   Add an error message.  Avoid the error when freeing a channel.
Files:      src/structs.h, src/channel.c


*** ../vim-7.4.1826/src/structs.h	2016-05-09 17:20:08.492312468 +0200
--- src/structs.h	2016-05-09 17:46:44.442422193 +0200
***************
*** 1419,1424 ****
--- 1419,1426 ----
      int		ch_to_be_closed; /* When TRUE reading or writing failed and
  				  * the channel must be closed when it's safe
  				  * to invoke callbacks. */
+     int		ch_to_be_freed; /* When TRUE channel must be freed when it's
+ 				 * safe to invoke callbacks. */
      int		ch_error;	/* When TRUE an error was reported.  Avoids
  				 * giving pages full of error messages when
  				 * the other side has exited, only mention the
*** ../vim-7.4.1826/src/channel.c	2016-05-09 17:20:08.496312424 +0200
--- src/channel.c	2016-05-09 17:51:57.102860175 +0200
***************
*** 59,64 ****
--- 59,67 ----
  /* Whether a redraw is needed for appending a line to a buffer. */
  static int channel_need_redraw = FALSE;
  
+ /* Whether we are inside channel_parse_messages() or another situation where it
+  * is safe to invoke callbacks. */
+ static int safe_to_invoke_callback = 0;
  
  #ifdef WIN32
      static int
***************
*** 403,410 ****
  {
      if (!in_free_unref_items)
      {
! 	channel_free_contents(channel);
! 	channel_free_channel(channel);
      }
  }
  
--- 406,420 ----
  {
      if (!in_free_unref_items)
      {
! 	if (safe_to_invoke_callback == 0)
! 	{
! 	    channel->ch_to_be_freed = TRUE;
! 	}
! 	else
! 	{
! 	    channel_free_contents(channel);
! 	    channel_free_channel(channel);
! 	}
      }
  }
  
***************
*** 444,449 ****
--- 454,463 ----
      int		did_free = FALSE;
      channel_T	*ch;
  
+     /* This is invoked from the garbage collector, which only runs at a safe
+      * point. */
+     ++safe_to_invoke_callback;
+ 
      for (ch = first_channel; ch != NULL; ch = ch->ch_next)
  	if (!channel_still_useful(ch)
  				 && (ch->ch_copyID & mask) != (copyID & mask))
***************
*** 453,458 ****
--- 467,474 ----
  	    channel_free_contents(ch);
  	    did_free = TRUE;
  	}
+ 
+     --safe_to_invoke_callback;
      return did_free;
  }
  
***************
*** 1450,1455 ****
--- 1466,1474 ----
      typval_T	rettv;
      int		dummy;
  
+     if (safe_to_invoke_callback == 0)
+ 	EMSG("INTERNAL: Invoking callback when it is not safe");
+ 
      argv[0].v_type = VAR_CHANNEL;
      argv[0].vval.v_channel = channel;
  
***************
*** 3515,3520 ****
--- 3534,3541 ----
      int		r;
      int		part = PART_SOCK;
  
+     ++safe_to_invoke_callback;
+ 
      /* Only do this message when another message was given, otherwise we get
       * lots of them. */
      if (did_log_msg)
***************
*** 3532,3537 ****
--- 3553,3565 ----
  	    channel = first_channel;
  	    continue;
  	}
+ 	if (channel->ch_to_be_freed)
+ 	{
+ 	    channel_free(channel);
+ 	    /* channel has been freed, start over */
+ 	    channel = first_channel;
+ 	    continue;
+ 	}
  	if (channel->ch_refcount == 0 && !channel_still_useful(channel))
  	{
  	    /* channel is no longer useful, free it */
***************
*** 3572,3577 ****
--- 3600,3607 ----
  	redraw_after_callback();
      }
  
+     --safe_to_invoke_callback;
+ 
      return ret;
  }
  
*** ../vim-7.4.1826/src/version.c	2016-05-09 17:20:08.496312424 +0200
--- src/version.c	2016-05-09 17:37:26.784701922 +0200
***************
*** 755,756 ****
--- 755,758 ----
  {   /* Add new patch number below this line */
+ /**/
+     1827,
  /**/

-- 
Computers make very fast, very accurate, mistakes.

 /// Bram Moolenaar -- Bram@Moolenaar.net -- http://www.Moolenaar.net   \\\
///        sponsor Vim, vote for features -- http://www.Vim.org/sponsor/ \\\
\\\  an exciting new programming language -- http://www.Zimbu.org        ///
 \\\            help me help AIDS victims -- http://ICCF-Holland.org    ///