From 08276e58732272cb244ea54b2abc1c198132f284 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?John=20Ankarstr=C3=B6m?= <john@ankarstrom.se>
Date: Fri, 9 Jul 2021 15:56:28 +0200
Subject: wpdf: Support build(1) syntax in source file

---
 wpdf | 38 +++++++++++++++++++++++++++++---------
 1 file changed, 29 insertions(+), 9 deletions(-)

(limited to 'wpdf')

diff --git a/wpdf b/wpdf
index a906c67..94e5029 100755
--- a/wpdf
+++ b/wpdf
@@ -12,8 +12,9 @@ my $parent = $$;  # pid of parent
 $SIG{USR1} = sub { kill 'HUP', 0 if not --$alive };
 $SIG{HUP} = sub { exit 0 };
 
-# collect dependencies for given pdf files
+# collect dependencies for given files
 for my $target (@ARGV) {
+	# if pdf, collect from Makefile
 	if ($target =~ /\.pdf$/) {
 		(my $basename = $target) =~ s/\.pdf$//;
 		open my $f, '<', 'Makefile'
@@ -32,18 +33,37 @@ for my $target (@ARGV) {
 			}
 		}
 		close $f;
-		if (fork == 0) {
-			system 'xpdf', '-remote', "wpdf-$target", $target;
-			kill 'USR1', $parent;
-			exit;
+	}
+
+	# if not pdf, assume target is actually source file and collect from it
+	# (with build(1) syntax)
+	else {
+		my $i = 0;
+		my $source = $target;
+		$target =~ s,\.[^./]*$,,; $target .= '.pdf';
+		$deptarget{$source} = $target;
+
+		open my $f, '<', $source;
+		while (<$f>) {
+			last if ++$i > 20;
+			if (/\s% (.*)/) {
+				$deptarget{$_} = $target for split /\s/, $1;
+				last;
+			}
 		}
-		$alive++;
-		next;
-	} else {
-		warn "skipping $_: not a pdf\n";
+		close $f;
 	}
+
+	if (fork == 0) {
+		system 'xpdf', '-remote', "wpdf-$target", $target;
+		kill 'USR1', $parent;
+		exit;
+	}
+	$alive++;
 }
 
+die "no dependencies found\n" if not keys %deptarget;
+
 # make pdf on demand
 open my $p, '-|', 'watch', keys %deptarget
 	or die "could not start watch: $!\n";
-- 
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