From d26f20ff4f4494c4dfe26793918edf9c42ecd47d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?John=20Ankarstr=C3=B6m?= <john@ankarstrom.se>
Date: Mon, 21 Jun 2021 11:20:58 +0200
Subject: wpdf: Support implicit dependencies

---
 wpdf | 38 +++++++++++++++++++++++++-------------
 1 file changed, 25 insertions(+), 13 deletions(-)

(limited to 'wpdf')

diff --git a/wpdf b/wpdf
index 58409db..304f687 100755
--- a/wpdf
+++ b/wpdf
@@ -5,34 +5,46 @@
 use strict;
 use warnings;
 
-my %deps;
+my %deptarget; # dependency => target
 
 # collect dependencies for given pdf files
-for (@ARGV) {
-	if (/\.pdf$/) {
-		(my $name = $_) =~ s/\.pdf$//;
+for my $target (@ARGV) {
+	if ($target =~ /\.pdf$/) {
+		# try to directly parse out dependencies
 		open my $f, '<', 'Makefile'
 			or die "could not open Makefile: $!\n";
 		while (<$f>) {
-			if (/^\Q$name.pdf\E:\s*(.*)/) {
-				$deps{$_} = $name for split /\s/, $1;
-				last;
-			}
+			next if not /^\Q$target\E:\s*(.*)/;
+			$deptarget{$_} = $target for split /\s/, $1;
+			goto found;
 		}
-		close $f;
-		exec('xpdf', '-remote', "wpdf-$name", "$name.pdf") if fork == 0;
+
+		# try to get implicit dependencies
+		(my $esc = $target) =~ s/'/'"'"'/g;
+		open my $p, "make -ndv 2>&1 '$esc' |"
+			or die "could not run make: $!\n";
+		while (<$p>) {
+			next if not /^\Q$target\E:< = (.*)/;
+			$deptarget{$_} = $target for split /\s/, $1;
+			last;
+		}
+
+		close $p;
+found:		close $f;
+		exec('xpdf', '-remote', "wpdf-$target", $target) if fork == 0;
+		next;
 	} else {
 		warn "skipping $_: not a pdf\n";
 	}
 }
 
 # make pdf on demand
-open my $p, '-|', 'watch', keys %deps
+open my $p, '-|', 'watch', keys %deptarget
 	or die "could not start watch: $!\n";
 while (<$p>) {
 	chomp;
-	system('make', "$deps{$_}.pdf") == 0
-		&& system('xpdf', '-remote', "wpdf-$deps{$_}", '-reload');
+	system('make', "$deptarget{$_}") == 0
+		&& system('xpdf', '-remote', "wpdf-$deptarget{$_}", '-reload');
 }
 close $p;
 exit($? != 0);
-- 
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