From 309621421193c2eebd6362df6b8850407bc77df9 Mon Sep 17 00:00:00 2001
From: VG <vg@devys.org>
Date: Tue, 29 Mar 2016 17:43:04 +0200
Subject: wip

---
 tests/wqueue2.py | 43 ++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 42 insertions(+), 1 deletion(-)

diff --git a/tests/wqueue2.py b/tests/wqueue2.py
index a78f315..4910b2f 100755
--- a/tests/wqueue2.py
+++ b/tests/wqueue2.py
@@ -1,7 +1,46 @@
-#!/usr/bin/python3.5
+"""
+Manage a queue of files for processing them sequentialy.
+"""
+
 
 import asyncio
 import os
+import functools
+import shutils
+
+
+u8open = functools.partial(open, encoding='utf8')
+
+
+class PersistentQueue:
+
+    def __init__(self, filename):
+        self.filename = filename
+        self.lock = asyncio.Lock()
+
+
+    def append(self, item):
+        async with lock:
+            with u8open(self.filename, 'a') as f:
+                await f.write(item)
+                await f.write('\n')
+
+    async def pop(self):
+        # TODO: when wanting to pop an empty queue the pop should wait
+        # asynchronously for a new filename to arrive
+        error
+        firstline = None
+        async with lock:
+            with u8open(filename, 'r') as f, \
+                       u8open(filename + '.tmp', 'w') as fo:
+                async for line in f:
+                    if not firstline:
+                        firstline = line
+                    else:
+                        await fo.write(line)
+            shutils.mv(filename + '.tmp', filename)
+        return firstline
+
 
 async def test():
     print('sleeping...')
@@ -26,8 +65,10 @@ async def manage_client(reader, writer):
 
 
 async def manage_jobs():
+    pq = PersistentQueue('queue.txt')
     queue = []
     while True:
+        item = await pq.pop()
         async with open('queue.txt') as f:
             line = await next(f)
             if not line:
-- 
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