From a4197ea6ffc5c1550e8b52d5a654bcaaaee04a4e Mon Sep 17 00:00:00 2001
From: markus schnalke <meillo@marmaro.de>
Date: Sat, 14 Apr 2012 19:59:54 +0200
Subject: [PATCH] mhshow: Automatically invoke (one) pager for the whole
 message, if on TTY. Mhshow used to invoke the pager for
 each of the text/plain parts independently. Now, we invoke
 it once for the whole message. Remember: We serialize!
 (Mhl(1) invokes a pager too, currently, but not much
 longer.)

---
 man/mhshow.man1 |   10 +++++++-
 uip/mhshow.c    |   76 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 85 insertions(+), 1 deletion(-)

diff --git a/man/mhshow.man1 b/man/mhshow.man1
index 79975ef..ecd2e9d 100644
--- a/man/mhshow.man1
+++ b/man/mhshow.man1
@@ -118,6 +118,14 @@ non\-empty, then
 will remove each of the messages shown
 from each sequence named by the profile entry.
 .SS "Showing the Contents"
+.B Mhshow
+prints messages in a convenient representation.
+If
+.B mhshow
+is outputting to a terminal, then
+a pager will be placed between the terminal and
+.BR mhshow .
+.PP
 The headers of each message are displayed with
 .B mhl
 using the standard format file
@@ -366,7 +374,7 @@ installation.
 ^Current\-Folder:~^To find the default current folder
 ^Unseen\-Sequence:~^To name sequences denoting unseen messages
 ^mhshow-show-<type>*~^Template for displaying contents
-^Pager:~^Default program to display text/plain content
+^Pager:~^Program to use as interactive front\-end
 .fi
 
 .SH "SEE ALSO"
diff --git a/uip/mhshow.c b/uip/mhshow.c
index 53f96f2..c323867 100644
--- a/uip/mhshow.c
+++ b/uip/mhshow.c
@@ -79,6 +79,8 @@ void freects_done(int) NORETURN;
 ** static prototypes
 */
 static void pipeser(int);
+static void m_popen(char *);
+static void m_pclose(void);
 
 
 int
@@ -92,6 +94,7 @@ main(int argc, char **argv)
 	struct msgs *mp = NULL;
 	CT ct, *ctp;
 	FILE *fp;
+	int ontty = 0;
 
 	done=freects_done;
 
@@ -313,11 +316,19 @@ main(int argc, char **argv)
 		}
 	}
 
+	if ((ontty = isatty(fileno(stdout)))) {
+		m_popen(defaultpager);
+	}
+
 	/*
 	** Show the message content
 	*/
 	show_all_messages(cts);
 
+	if (ontty) {
+		m_pclose();
+	}
+
 	/* Now free all the structures for the content */
 	for (ctp = cts; *ctp; ctp++)
 		free_content(*ctp);
@@ -351,3 +362,68 @@ pipeser(int i)
 	done(1);
 	/* NOTREACHED */
 }
+
+
+static int m_pid = NOTOK;
+static int sd = NOTOK;
+
+
+static void
+m_popen(char *name)
+{
+	int pd[2];
+
+	if ((sd = dup(fileno(stdout))) == NOTOK)
+		adios("standard output", "unable to dup()");
+
+	if (pipe(pd) == NOTOK)
+		adios("pipe", "unable to");
+
+	switch (m_pid = fork()) {
+	case NOTOK:
+		adios("fork", "unable to");
+
+	case OK:
+		SIGNAL(SIGINT, SIG_DFL);
+		SIGNAL(SIGQUIT, SIG_DFL);
+
+		close(pd[1]);
+		if (pd[0] != fileno(stdin)) {
+			dup2(pd[0], fileno(stdin));
+			close(pd[0]);
+		}
+		execlp(name, mhbasename(name), NULL);
+		fprintf(stderr, "unable to exec ");
+		perror(name);
+		_exit(-1);
+
+	default:
+		close(pd[0]);
+		if (pd[1] != fileno(stdout)) {
+			dup2(pd[1], fileno(stdout));
+			close(pd[1]);
+		}
+	}
+}
+
+
+void
+m_pclose(void)
+{
+	if (m_pid == NOTOK)
+		return;
+
+	if (sd != NOTOK) {
+		fflush(stdout);
+		if (dup2(sd, fileno(stdout)) == NOTOK)
+			adios("standard output", "unable to dup2()");
+
+		clearerr(stdout);
+		close(sd);
+		sd = NOTOK;
+	} else
+		fclose(stdout);
+
+	pidwait(m_pid, OK);
+	m_pid = NOTOK;
+}
-- 
1.7.10.4