Initial draft of API for background processing.

5 files changed, 129 insertions, 0 deletions

diff --git a/Makefile b/Makefile
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+++ b/Makefile
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+PYTHON = python
+
+all:
+
+check: all
+	$(PYTHON) -m CoverageTestRunner --ignore-missing-from=without-tests
+	rm .coverage
+	
+clean:
+	rm -f *.py[co]
diff --git a/bgproc.py b/bgproc.py
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+++ b/bgproc.py
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+# Copyright 2011  Lars Wirzenius
+# 
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+# 
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+# 
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+
+class BackgroundProcessing(object):
+
+    '''Manage background processing queues.'''
+    
+    def __init__(self, func):
+        self.pending_requests = 0
+        
+    def enqueue_request(self, request):
+        '''Put a request into queue, to be processed by workers whenever.'''
+        
+    def close_requests(self):
+        '''Signal workers that they can retire.
+        
+        All pending requests will be processed, but after the queue
+        is empty, the workers will finish. No more requests may be
+        enqueued.
+        
+        '''
+        
+    def wait_for_results(self):
+        '''Block until there are results available.
+
+        No blocking if results are already available.
+        Return True if there are results available,
+        False if there will be no more results,
+        because all requests have been processed.
+        
+        '''
+
+    def __iter__(self):
+        '''Iterate over immediately available results.'''
diff --git a/bgproc_tests.py b/bgproc_tests.py
new file mode 100644
index 0000000..4e1a87e
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+++ b/bgproc_tests.py
@@ -0,0 +1,36 @@
+# Copyright 2011  Lars Wirzenius
+# 
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+# 
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+# 
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+
+import unittest
+
+import bgproc
+
+
+requests = []
+
+def callback(request):
+    requests.append(request)
+    return len(requests)
+
+
+class BackgroundProcessingTests(unittest.TestCase):
+
+    def setUp(self):
+        del requests[:]
+        self.bg = bgproc.BackgroundProcessing(callback)
+    
+    def test_no_pending_requests_initially(self):
+        self.assertEqual(self.bg.pending_requests, 0)
diff --git a/example.py b/example.py
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index 0000000..88a2dbe
--- /dev/null
+++ b/example.py
@@ -0,0 +1,35 @@
+#!/usr/bin/python
+# Copyright 2011  Lars Wirzenius
+# 
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+# 
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+# 
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+
+import bgproc
+
+
+N = 10
+
+
+def inc(request):
+    return request + 1
+
+
+bg = bgproc.BackgroundProcessing(inc)
+for i in range(N):
+    bg.enqueue_request(i)
+bg.close_requests()
+while bg.wait_for_results():
+    for result in bg:
+        print result
+
diff --git a/without-tests b/without-tests
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index 0000000..a73a36d
--- /dev/null
+++ b/without-tests
@@ -0,0 +1 @@
+./example.py