Re: [RFC PATCH 5/5] show: Simplify new text formatter code

Subject: Re: [RFC PATCH 5/5] show: Simplify new text formatter code

Date: Thu, 26 Jan 2012 01:35:26 -0500

To: Dmitry Kurochkin

Cc: notmuch@notmuchmail.org

From: Austin Clements


Quoth Dmitry Kurochkin on Jan 24 at  5:49 am:
> On Wed, 11 Jan 2012 20:49:33 -0500, Austin Clements <amdragon@MIT.EDU> wrote:
> > This makes the text formatter take advantage of the new code
> > structure.  The previously duplicated header logic is now unified,
> > several things that we used to compute repeatedly across different
> > callbacks are now computed once, and the code is generally simplified.
> > 
> > Unifying the header logic causes this to format some dates slightly
> > differently, so the two affected test cases are updated.
> 
> Thanks for these patches, Austin.  They are a definite improvement for
> notmuch show code.  I hope it would soon get pushed to master.  And I
> hope more patches would follow :)
> 
> Few minor comments below.
> 
> > ---
> >  notmuch-show.c     |   84 ++++++++++++----------------------------------------
> >  test/crypto        |    2 +-
> >  test/thread-naming |   16 +++++-----
> >  3 files changed, 28 insertions(+), 74 deletions(-)
> > 
> > diff --git a/notmuch-show.c b/notmuch-show.c
> > index 3241965..1689222 100644
> > --- a/notmuch-show.c
> > +++ b/notmuch-show.c
> > @@ -175,67 +175,42 @@ format_part_text (const void *ctx, mime_node_t *node,
> >      GMimeObject *meta = node->envelope_part ?
> >  	GMIME_OBJECT (node->envelope_part) : node->part;
> >      GMimeContentType *content_type = g_mime_object_get_content_type (meta);
> > +    GMimeContentDisposition *disposition =
> > +	g_mime_object_get_content_disposition (meta);
> > +    notmuch_bool_t attachment = disposition &&
> > +	strcmp (disposition->disposition, GMIME_DISPOSITION_ATTACHMENT) == 0;
> 
> If I did not miss anything, attachment is used only as following:
> 
>   attachment ? "attachment" : "part"
> 
> Please make it const char[] and set to "attachment" or "part".

Ooh, good catch.  But I'll do you one better.  I introduced a const
char *part_type that's set to "attachment", "part", *or* "message" in
the if structure below.  That eliminates the attachment variable,
moves the disposition variable back down into one of the early if
bodies, and eliminates the entire conditional the figures out what to
print to close the block.

> > +    notmuch_bool_t leaf = GMIME_IS_PART (node->part);
> 
> Please add const where possible to local variables (e.g. attachment, leaf).

Generally I consider these overkill on local non-pointer variables,
but okay.  leaf wound up being the only one I had to add it to.

> >      int i;
> >  
> >      if (node->envelope_file) {
> >  	notmuch_message_t *message = node->envelope_file;
> > -	const char *headers[] = {
> > -	    "Subject", "From", "To", "Cc", "Bcc", "Date"
> > -	};
> > -	const char *name, *value;
> > -	unsigned int i;
> >  
> > -	printf ("\fmessage{ ");
> > -	printf ("id:%s depth:%d match:%d filename:%s\n",
> > +	printf ("\fmessage{ id:%s depth:%d match:%d filename:%s\n",
> >  		notmuch_message_get_message_id (message),
> >  		indent,
> >  		notmuch_message_get_flag (message, NOTMUCH_MESSAGE_FLAG_MATCH),
> >  		notmuch_message_get_filename (message));
> > -
> > -	printf ("\fheader{\n");
> > -
> > -	printf ("%s\n", _get_one_line_summary (ctx, message));
> > -
> > -	for (i = 0; i < ARRAY_SIZE (headers); i++) {
> > -	    name = headers[i];
> > -	    value = notmuch_message_get_header (message, name);
> > -	    if (value && strlen (value))
> > -		printf ("%s: %s\n", name, value);
> > -	}
> > -	printf ("\fheader}\n");
> 
> Yay!  Only one header-printing code left :)
> 
> >      } else {
> > -	GMimeContentDisposition *disposition = g_mime_object_get_content_disposition (meta);
> >  	const char *cid = g_mime_object_get_content_id (meta);
> > +	const char *filename = leaf ?
> > +	    g_mime_part_get_filename (GMIME_PART (node->part)) : NULL;
> >  
> > -	if (disposition &&
> > -	    strcmp (disposition->disposition, GMIME_DISPOSITION_ATTACHMENT) == 0)
> > -	{
> > -	    printf ("\fattachment{ ID: %d", node->part_num);
> > -
> > -	} else {
> > -
> > -	    printf ("\fpart{ ID: %d", node->part_num);
> > -	}
> > -
> > -	if (GMIME_IS_PART (node->part))
> > -	{
> > -	    const char *filename = g_mime_part_get_filename (GMIME_PART (node->part));
> > -	    if (filename)
> > -		printf (", Filename: %s", filename);
> > -	}
> > -
> > +	printf ("\f%s{ ID: %d", attachment ? "attachment" : "part", node->part_num);
> > +	if (filename)
> 
> I always forget about it, can we declare variables inside if condition
> like in C++?  I.e.:
> 
>   if (const char *filename = leaf ? g_mime_part_get_filename (GMIME_PART (node->part)) : NULL)
> 
> If yes, I would prefer to use this style where possible.

You can do that in C++?  You definitely can't do that in C.

> > +	    printf (", Filename: %s", filename);
> >  	if (cid)
> >  	    printf (", Content-id: %s", cid);
> > -
> 
> I would revert blank line changes.  But I do not insist :)

Eh.  I'm generally opposed to drive-by fixes, but this code inherited
a lot of funny formatting that just interrupts the whole flow when the
code is all in one place.

> >  	printf (", Content-type: %s\n", g_mime_content_type_to_string (content_type));
> >      }
> >  
> > -    if (node->envelope_part) {
> > +    if (GMIME_IS_MESSAGE (node->part)) {
> 
> This condition is repeated at least twice.  Please consider moving the
> message variable below to the top level and using it in the conditions.

If the downcast had to be done in both places I would, but since the
conditional itself is the only repetition, I prefer to minimize the
scope of the message variable.

Thanks for the review!  I'll send a new version shortly.

> Regards,
>   Dmitry
> 
> >  	GMimeMessage *message = GMIME_MESSAGE (node->part);
> >  	InternetAddressList *recipients;
> >  	const char *recipients_string;
> >  
> >  	printf ("\fheader{\n");
> > +	if (node->envelope_file)
> > +	    printf ("%s\n", _get_one_line_summary (ctx, node->envelope_file));
> >  	printf ("Subject: %s\n", g_mime_message_get_subject (message));
> >  	printf ("From: %s\n", g_mime_message_get_sender (message));
> >  	recipients = g_mime_message_get_recipients (message, GMIME_RECIPIENT_TYPE_TO);
> > @@ -248,9 +223,11 @@ format_part_text (const void *ctx, mime_node_t *node,
> >  	    printf ("Cc: %s\n", recipients_string);
> >  	printf ("Date: %s\n", g_mime_message_get_date_as_string (message));
> >  	printf ("\fheader}\n");
> > +
> > +	printf ("\fbody{\n");
> >      }
> >  
> > -    if (!node->envelope_file) {
> > +    if (leaf) {
> >  	if (g_mime_content_type_is_type (content_type, "text", "*") &&
> >  	    !g_mime_content_type_is_type (content_type, "text", "html"))
> >  	{
> > @@ -258,24 +235,12 @@ format_part_text (const void *ctx, mime_node_t *node,
> >  	    g_mime_stream_file_set_owner (GMIME_STREAM_FILE (stream_stdout), FALSE);
> >  	    show_text_part_content (node->part, stream_stdout);
> >  	    g_object_unref(stream_stdout);
> > -	}
> > -	else if (g_mime_content_type_is_type (content_type, "multipart", "*") ||
> > -		 g_mime_content_type_is_type (content_type, "message", "rfc822"))
> > -	{
> > -	    /* Do nothing for multipart since its content will be printed
> > -	     * when recursing. */
> > -	}
> > -	else
> > -	{
> > +	} else {
> >  	    printf ("Non-text part: %s\n",
> >  		    g_mime_content_type_to_string (content_type));
> >  	}
> >      }
> >  
> > -    if (GMIME_IS_MESSAGE (node->part)) {
> > -	printf ("\fbody{\n");
> > -    }
> > -
> >      for (i = 0; i < node->nchildren; i++)
> >  	format_part_text (ctx, mime_node_child (node, i), indent, params);
> >  
> > @@ -286,18 +251,7 @@ format_part_text (const void *ctx, mime_node_t *node,
> >      if (node->envelope_file) {
> >  	printf ("\fmessage}\n");
> >      } else {
> > -	GMimeContentDisposition *disposition;
> > -
> > -	disposition = g_mime_object_get_content_disposition (meta);
> > -	if (disposition &&
> > -	    strcmp (disposition->disposition, GMIME_DISPOSITION_ATTACHMENT) == 0)
> > -	{
> > -	    printf ("\fattachment}\n");
> > -	}
> > -	else
> > -	{
> > -	    printf ("\fpart}\n");
> > -	}
> > +	printf ("\f%s}\n", attachment ? "attachment" : "part");
> >      }
> >  }
> >  
> > diff --git a/test/crypto b/test/crypto
> > index 0af4aa8..6723ef8 100755
> > --- a/test/crypto
> > +++ b/test/crypto
> > @@ -157,7 +157,7 @@ Notmuch Test Suite <test_suite@notmuchmail.org> (2000-01-01) (encrypted inbox)
> >  Subject: test encrypted message 001
> >  From: Notmuch Test Suite <test_suite@notmuchmail.org>
> >  To: test_suite@notmuchmail.org
> > -Date: 01 Jan 2000 12:00:00 -0000
> > +Date: Sat, 01 Jan 2000 12:00:00 +0000
> >  header}
> >  body{
> >  part{ ID: 1, Content-type: multipart/encrypted
> > diff --git a/test/thread-naming b/test/thread-naming
> > index 41b97d9..b7c96f2 100755
> > --- a/test/thread-naming
> > +++ b/test/thread-naming
> > @@ -71,7 +71,7 @@ Notmuch Test Suite <test_suite@notmuchmail.org> (2001-01-05) (unread)
> >  Subject: thread-naming: Initial thread subject
> >  From: Notmuch Test Suite <test_suite@notmuchmail.org>
> >  To: Notmuch Test Suite <test_suite@notmuchmail.org>
> > -Date: Fri, 05 Jan 2001 15:43:56 -0000
> > +Date: Fri, 05 Jan 2001 15:43:56 +0000
> >  header}
> >  body{
> >  part{ ID: 1, Content-type: text/plain
> > @@ -85,7 +85,7 @@ Notmuch Test Suite <test_suite@notmuchmail.org> (2001-01-06) (inbox unread)
> >  Subject: thread-naming: Older changed subject
> >  From: Notmuch Test Suite <test_suite@notmuchmail.org>
> >  To: Notmuch Test Suite <test_suite@notmuchmail.org>
> > -Date: Sat, 06 Jan 2001 15:43:56 -0000
> > +Date: Sat, 06 Jan 2001 15:43:56 +0000
> >  header}
> >  body{
> >  part{ ID: 1, Content-type: text/plain
> > @@ -99,7 +99,7 @@ Notmuch Test Suite <test_suite@notmuchmail.org> (2001-01-07) (inbox unread)
> >  Subject: thread-naming: Newer changed subject
> >  From: Notmuch Test Suite <test_suite@notmuchmail.org>
> >  To: Notmuch Test Suite <test_suite@notmuchmail.org>
> > -Date: Sun, 07 Jan 2001 15:43:56 -0000
> > +Date: Sun, 07 Jan 2001 15:43:56 +0000
> >  header}
> >  body{
> >  part{ ID: 1, Content-type: text/plain
> > @@ -113,7 +113,7 @@ Notmuch Test Suite <test_suite@notmuchmail.org> (2001-01-08) (unread)
> >  Subject: thread-naming: Final thread subject
> >  From: Notmuch Test Suite <test_suite@notmuchmail.org>
> >  To: Notmuch Test Suite <test_suite@notmuchmail.org>
> > -Date: Mon, 08 Jan 2001 15:43:56 -0000
> > +Date: Mon, 08 Jan 2001 15:43:56 +0000
> >  header}
> >  body{
> >  part{ ID: 1, Content-type: text/plain
> > @@ -127,7 +127,7 @@ Notmuch Test Suite <test_suite@notmuchmail.org> (2001-01-09) (inbox unread)
> >  Subject: Re: thread-naming: Initial thread subject
> >  From: Notmuch Test Suite <test_suite@notmuchmail.org>
> >  To: Notmuch Test Suite <test_suite@notmuchmail.org>
> > -Date: Tue, 09 Jan 2001 15:43:45 -0000
> > +Date: Tue, 09 Jan 2001 15:43:45 +0000
> >  header}
> >  body{
> >  part{ ID: 1, Content-type: text/plain
> > @@ -141,7 +141,7 @@ Notmuch Test Suite <test_suite@notmuchmail.org> (2001-01-10) (inbox unread)
> >  Subject: Aw: thread-naming: Initial thread subject
> >  From: Notmuch Test Suite <test_suite@notmuchmail.org>
> >  To: Notmuch Test Suite <test_suite@notmuchmail.org>
> > -Date: Wed, 10 Jan 2001 15:43:45 -0000
> > +Date: Wed, 10 Jan 2001 15:43:45 +0000
> >  header}
> >  body{
> >  part{ ID: 1, Content-type: text/plain
> > @@ -155,7 +155,7 @@ Notmuch Test Suite <test_suite@notmuchmail.org> (2001-01-11) (inbox unread)
> >  Subject: Vs: thread-naming: Initial thread subject
> >  From: Notmuch Test Suite <test_suite@notmuchmail.org>
> >  To: Notmuch Test Suite <test_suite@notmuchmail.org>
> > -Date: Thu, 11 Jan 2001 15:43:45 -0000
> > +Date: Thu, 11 Jan 2001 15:43:45 +0000
> >  header}
> >  body{
> >  part{ ID: 1, Content-type: text/plain
> > @@ -169,7 +169,7 @@ Notmuch Test Suite <test_suite@notmuchmail.org> (2001-01-12) (inbox unread)
> >  Subject: Sv: thread-naming: Initial thread subject
> >  From: Notmuch Test Suite <test_suite@notmuchmail.org>
> >  To: Notmuch Test Suite <test_suite@notmuchmail.org>
> > -Date: Fri, 12 Jan 2001 15:43:45 -0000
> > +Date: Fri, 12 Jan 2001 15:43:45 +0000
> >  header}
> >  body{
> >  part{ ID: 1, Content-type: text/plain
> 

-- 
Austin Clements                                      MIT/'06/PhD/CSAIL
amdragon@mit.edu                           http://web.mit.edu/amdragon
       Somewhere in the dream we call reality you will find me,
              searching for the reality we call dreams.

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