From a0bb92c9f397eb69914be03d7de16ae8e83e7426 Mon Sep 17 00:00:00 2001
From: "m@mmmmarascio.xyz" <m@mmmmarascio.xyz>
Date: Mon, 1 Aug 2016 11:25:57 +0200
Subject: [PATCH] Enable inc(1) to read from stdin

The -file switch handles the argument "-" special and reads
from stdin in this case.
---
 man/inc.man1                   |    7 +++++
 test/tests/inc/test-read-stdin |   66 ++++++++++++++++++++++++++++++++++++++++
 uip/inc.c                      |   49 +++++++++++++++--------------
 3 files changed, 100 insertions(+), 22 deletions(-)
 create mode 100644 test/tests/inc/test-read-stdin

diff --git a/man/inc.man1 b/man/inc.man1
index 817c1bd..ed586c1 100644
--- a/man/inc.man1
+++ b/man/inc.man1
@@ -124,6 +124,13 @@ By using the
 switch, one can direct
 .B inc
 to incorporate messages from a file other than the user's maildrop.
+In particular, if
+.I name
+is
+.RI ` - '
+then
+.B inc
+will read messages from standard input.
 Note that the named file will NOT be zeroed, unless the
 .B \-truncate
 switch is given.
diff --git a/test/tests/inc/test-read-stdin b/test/tests/inc/test-read-stdin
new file mode 100644
index 0000000..d771d32
--- /dev/null
+++ b/test/tests/inc/test-read-stdin
@@ -0,0 +1,66 @@
+#!/bin/sh
+##########################################################
+# Test incorporating mail from stdin with `inc -file -`. #
+##########################################################
+. "$MH_TEST_COMMON"
+
+# Test empty stdin from a pipe.
+runandcheck "printf '' |inc -file -" <<!
+Incorporating new mail into inbox...
+
+inc: no messages incorporated, continuing...
+!
+
+# Test empty stdin from redirected regular file.
+cd "$MMH_TEST_DIR"
+f=mbox
+runandcheck "printf '' >$f && inc -file - <$f" <<!
+Incorporating new mail into inbox...
+
+inc: no messages incorporated, continuing...
+!
+rm "$f"
+unset f
+
+# Test empty stdin from character device.
+runandcheck "inc -file - </dev/null" <<!
+Incorporating new mail into inbox...
+
+inc: no messages incorporated, continuing...
+!
+
+# Test nonempty pipe.
+runandcheck "packf +inbox |inc -file -" <<!
+Incorporating new mail into inbox...
+
+  11+ 2006-09-29 00:00  Test1              Testing message 1
+  12  2006-09-29 00:00  Test2              Testing message 2
+  13  2006-09-29 00:00  Test3              Testing message 3
+  14  2006-09-29 00:00  Test4              Testing message 4
+  15  2006-09-29 00:00  Test5              Testing message 5
+  16  2006-09-29 00:00  Test6              Testing message 6
+  17  2006-09-29 00:00  Test7              Testing message 7
+  18  2006-09-29 00:00  Test8              Testing message 8
+  19  2006-09-29 00:00  Test9              Testing message 9
+  20  2006-09-29 00:00  Test10             Testing message 10
+!
+
+# Test nonempty redirected stdin.
+cd "$MMH_TEST_DIR"
+f=mbox
+runandcheck "packf +inbox 1-10 >$f && inc -file - <$f" <<!
+Incorporating new mail into inbox...
+
+  21+ 2006-09-29 00:00  Test1              Testing message 1
+  22  2006-09-29 00:00  Test2              Testing message 2
+  23  2006-09-29 00:00  Test3              Testing message 3
+  24  2006-09-29 00:00  Test4              Testing message 4
+  25  2006-09-29 00:00  Test5              Testing message 5
+  26  2006-09-29 00:00  Test6              Testing message 6
+  27  2006-09-29 00:00  Test7              Testing message 7
+  28  2006-09-29 00:00  Test8              Testing message 8
+  29  2006-09-29 00:00  Test9              Testing message 9
+  30  2006-09-29 00:00  Test10             Testing message 10
+!
+rm "$f"
+unset f
diff --git a/uip/inc.c b/uip/inc.c
index 0cb2a5e..c0f272e 100644
--- a/uip/inc.c
+++ b/uip/inc.c
@@ -225,10 +225,10 @@ main(int argc, char **argv)
 				continue;
 
 			case FILESW:
-				if (!(cp = *argp++) || *cp == '-')
+				if (!(cp = *argp++))
 					adios(EX_USAGE, NULL, "missing argument to %s",
 							argp[-2]);
-				from = mh_xstrdup(expanddir(cp));
+				from = (strcmp(cp, "-")==0) ? "-" : mh_xstrdup(expanddir(cp));
 
 				/*
 				** If the truncate file is in default state,
@@ -277,26 +277,28 @@ main(int argc, char **argv)
 	/* guarantee dropping group priveleges; we might not have done so earlier */
 	DROPGROUPPRIVS();
 
-	/*
-	** We will get the mail from a file
-	** (typically the standard maildrop)
-	*/
-	if (from)
-		newmail = from;
-	else if ((newmail = getenv("MAILDROP")) && *newmail)
-		newmail = toabsdir(newmail);
-	else if ((newmail = context_find("maildrop")) && *newmail)
-		newmail = toabsdir(newmail);
-	else {
-		newmail = concat(mailspool, "/", getusername(), NULL);
-	}
-	if (stat(newmail, &s1) == NOTOK || s1.st_size == 0)
-		adios(EX_DATAERR, NULL, "no mail to incorporate");
+	if (from && strcmp(from, "-")==0) {
+		/* We'll read mail from stdin. */
+		newmail = NULL;
+	} else {
+		/* We'll read mail from a file. */
+		if (from)
+			newmail = from;
+		else if ((newmail = getenv("MAILDROP")) && *newmail)
+			newmail = toabsdir(newmail);
+		else if ((newmail = context_find("maildrop")) && *newmail)
+			newmail = toabsdir(newmail);
+		else {
+			newmail = concat(mailspool, "/", getusername(), NULL);
+		}
+		if (stat(newmail, &s1) == NOTOK || s1.st_size == 0)
+			adios(EX_DATAERR, NULL, "no mail to incorporate");
 
-	if ((cp = strdup(newmail)) == NULL)
-		adios(EX_OSERR, NULL, "error allocating memory to copy newmail");
+		if ((cp = strdup(newmail)) == NULL)
+			adios(EX_OSERR, NULL, "error allocating memory to copy newmail");
 
-	newmail = cp;
+		newmail = cp;
+	}
 
 	if (!folder)
 		folder = getdeffol();
@@ -313,7 +315,10 @@ main(int argc, char **argv)
 	if (!(mp = folder_read(folder)))
 		adios(EX_IOERR, NULL, "unable to read folder %s", folder);
 
-	if (access(newmail, W_OK) != NOTOK) {
+	if (!newmail) {
+		trnflag = 0;
+		in = stdin;
+	} else if (access(newmail, W_OK) != NOTOK) {
 		locked++;
 		if (trnflag) {
 			SIGNAL(SIGHUP, SIG_IGN);
@@ -480,7 +485,7 @@ giveup:;
 			else
 				admonish(newmail, "error zero'ing");
 		}
-	} else if (noisy) {
+	} else if (noisy && newmail) {
 		printf("%s not zero'd\n", newmail);
 	}
 
-- 
1.7.10.4