From e1f13107a25bfe3f0ccd7cf3425058b91631a5d4 Mon Sep 17 00:00:00 2001
From: Martin Langhoff <martin.langhoff@gmail.com>
Date: Fri, 13 Sep 2013 15:11:38 -0400
Subject: [PATCH] zcatfollows now works as smart tail

---
 zcatfollow | 25 ++++++++++++++++++++++++-
 1 file changed, 24 insertions(+), 1 deletion(-)

diff --git a/zcatfollow b/zcatfollow
index 04f73df..9a5eec1 100755
--- a/zcatfollow
+++ b/zcatfollow
@@ -11,11 +11,18 @@ import sys
 import gzip
 import zlib
 import time
+from collections import deque
 
 ## init globals used in sig handler
 # fh in append, binary
 f = gzip.open(sys.argv[1], 'r')
 
+# lookbehind buffer, defined as a list
+lbbufsize=10
+lbbuf=deque([])
+buffering=True
+bufferfull=False
+
 # while / readline() sidesteps magic input buffering
 while 1:
 	try:
@@ -30,9 +37,25 @@ while 1:
 	if not line:
 		if f.closed:
 			break
+		if buffering:
+			# got to the current tail of it
+			# dump our lookbehind buffer, stop buffering
+			for buf_line in lbbuf:
+				print buf_line
+			buffering=False
 		# internal gzip API use?
 		# f.decompress.flush()
 		time.sleep(0.1)
 	else:
-		print line
+		if not buffering:
+			print line
+		else:
+			if bufferfull:
+				lbbuf.popleft()
+				lbbuf.append(line)
+			else:
+				lbbuf.append(line)
+				if len(lbbuf) >= lbbufsize:
+					bufferfull=True
+
 
-- 
2.11.4.GIT