From ba4c894865589f7e813fca21c4995db15f8efbf1 Mon Sep 17 00:00:00 2001
From: Armaan Bhojwani <me@armaanb.net>
Date: Tue, 6 Jul 2021 19:58:06 -0400
Subject: [PATCH] rss: implement parallel downloads

---
 man/rss.1.scd |  8 +++++---
 rss           | 41 +++++++++++++++++++++++++----------------
 2 files changed, 30 insertions(+), 19 deletions(-)

diff --git a/man/rss.1.scd b/man/rss.1.scd
index 9ea9f7c..ba58ab2 100644
--- a/man/rss.1.scd
+++ b/man/rss.1.scd
@@ -4,11 +4,13 @@ rss(1)
 rss - fetch rss feeds and launch sfeed_curses
 
 # SYNOPSIS
-rss [path to feeds]
+rss [path to feeds] [number of threads]
 
 # DESCRIPTION
-Downloads feeds from the first argument (defaults to ~/org/feeds), and opens
-them in sfeed_curses. Depends on sfeed_curses and libxml2.
+Downloads RSS feeds listed in the file provided by the first argument (defaults
+to ~/org/feeds), and opens them in sfeed_curses. Download with as many parallel
+jobs as specified in the second argument (defaults to 4). Depends on
+sfeed_curses and libxml2.
 
 # COPYRIGHT
 This is free and unencumbered software released into the public domain. For more
diff --git a/rss b/rss
index cfd93e6..5a1da2d 100755
--- a/rss
+++ b/rss
@@ -1,24 +1,33 @@
 #!/usr/bin/env sh
 
-file=${2:-$HOME/org/feeds}
-total=$(wc -l "$file" | cut -d " " -f 1)
-cachedir=${XDG_CACHE_HOME:-$HOME/.cache/}/sfeed
+dl() {
+	while read -r feed; do
+		printf "Processing %s\n" "$feed"
+		curl -s "$feed" | xmllint --format - 1> /tmp/sfeed 2> /dev/null
+		
+		title="$(grep -m 1 title /tmp/sfeed | \
+			xmllint --xpath "string(//title)" - 2> /dev/null)"
+		domain=$(echo "$feed" | cut -d/ -f 3)
+		fname=$(echo "${title:-$domain}" | sed 's|/|!|g' | head -c 25)
+		sfeed < /tmp/sfeed > "$cachedir/$fname"
+	done < "$1"
+}
 
-mkdir -p "$cachedir"
+trap 'trap - SIGTERM && kill -- -$$' INT TERM EXIT
 
-i=1
-while read -r feed; do
-	printf "Downloading %s\n%s/%s\r" "$feed" "$i" "$total"
-	curl -s "$feed" | xmllint --format - > /tmp/sfeed
-	
-	title="$(grep -m 1 title /tmp/sfeed | xmllint --xpath "string(//title)" -)"
-	domain=$(echo "$feed" | cut -d/ -f 3)
-	fname=$(echo "${title:-$domain}" | sed 's|/|!|g' | head -c 25)
-	sfeed < /tmp/sfeed > "$cachedir/$fname"
+file=${1:-$HOME/org/feeds}
+total=$(wc -l "$file" | cut -d " " -f 1)
+cachedir=${XDG_CACHE_HOME:-$HOME/.cache/}/sfeed
+threads=${2:-4}
+pere=$(($((total + threads - 1)) / threads))
 
-	i=$((i+1))
-done < "$file"
+mkdir -p "$cachedir/split"
+(cd "$cachedir/split" || exit; split -l "$pere" "$file")
 
-rm /tmp/sfeed
+for j in "$cachedir/split"/*; do
+	dl "$j" &
+done
 
+wait
+rm -rf /tmp/sfeed "$cachedir/split"
 sfeed_curses "$cachedir"/*
-- 
2.39.2