From 18cf5a99d0eee6560ee2826969620bae30b91938 Mon Sep 17 00:00:00 2001
From: Silvio Rhatto <rhatto@riseup.net>
Date: Sun, 25 Aug 2013 22:28:21 -0300
Subject: Initial lockfile support

---
 README.mdwn             |  1 -
 httracker               |  4 ++--
 lib/httracker/functions | 52 +++++++++++++++++++++++++++++++++++++++++++++++--
 scuttler                |  4 ++--
 4 files changed, 54 insertions(+), 7 deletions(-)

diff --git a/README.mdwn b/README.mdwn
index 3309f60..169f469 100644
--- a/README.mdwn
+++ b/README.mdwn
@@ -16,4 +16,3 @@ TODO
 
 - Include all sites already donwloaded by scuttler.
 - Support for other fetchers like youtube-dl.
-- Lockfile support.
diff --git a/httracker b/httracker
index cd99f60..7fc33c1 100755
--- a/httracker
+++ b/httracker
@@ -18,5 +18,5 @@ fi
 # Iterate over all URLs
 httracker_iterate
 
-# Cleanup
-rm -rf $URLS
+# Done
+httracker_teardown
diff --git a/lib/httracker/functions b/lib/httracker/functions
index 8e8964e..e3c81c4 100644
--- a/lib/httracker/functions
+++ b/lib/httracker/functions
@@ -109,12 +109,60 @@ function httracker_setup_folders {
 }
 
 # Set basic environment
-function httracker_set_env {
+function httracker_initialize {
   source `dirname $0`/config || exit 1
 
   # Create folders
   httracker_setup_folders
+
+  # Lockfile
+  LOCKFILE="${TMP}/`basename $0`.lock"
+  httracker_check_lockfile
+  httracker_set_lockfile
+}
+
+# Cleanup environment
+function httracker_teardown {
+  httracker_unset_lockfile
+  rm -rf $URLS
+}
+
+# Create lockfile
+function httracker_set_lockfile {
+  if [ ! -z "$LOCKFILE" ]; then
+    mkdir -p `dirname $LOCKFILE`
+    if ( set -o noclobber; echo "$$" > "$LOCKFILE" ) &> /dev/null; then
+      trap 'httracker_unset_lockfile' INT TERM EXIT
+    else
+      echo "Could not create lockfile $LOCKFILE, exiting"
+      exit 1
+    fi
+  fi
+}
+
+# Remove lockfile
+function httracker_unset_lockfile {
+  if [ ! -z "$LOCKFILE" ]; then
+    $rm -f $LOCKFILE || echo "Could not remove lockfile $LOCKFILE"
+  fi
+}
+
+# Check lockfile
+function httracker_check_lockfile {
+  local pid process
+
+  if [ ! -z "$LOCKFILE" ] && [ -f "$LOCKFILE" ]; then
+    pid="`cat $LOCKFILE`"
+    process="`ps --no-headers -o comm $pid`"
+    if [ "$?" == "0" ] && [ "`ps --no-headers -o comm $$`" == "$process" ]; then
+      echo "Another program is running for $LOCKFILE, skipping run"
+      exit
+    else
+      echo "Found old lockfile $LOCKFILE, removing it"
+      unset_LOCKFILE
+    fi
+  fi
 }
 
 # Initialize
-httracker_set_env
+httracker_initialize
diff --git a/scuttler b/scuttler
index 1c64622..5dd383a 100755
--- a/scuttler
+++ b/scuttler
@@ -26,5 +26,5 @@ httracker_sqlquery "select bAddress from sc_bookmarks;" > ${URLS}
 # Download in mirror mode
 httracker_iterate
 
-# Cleanup
-rm -rf $URLS
+# Done
+httracker_teardown
-- 
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