Repair non-working example.py and speed-test

The introduction of the allow_writes parameter in larch/forest.py:open_forest()
broke example.py and speed-test.
Just adding the parameter to the open_forest calls was not enough to fix the
issue.  This patch fixes the issue by adding the allow_writes parameter where it
is needed beyond the open_forest calls.

Most notably, this patch changes the __init__ signature of the abstract base 
class larch.NodeStore from __init__(self, node_size, codec) to
__init__(self, allow_writes, node_size, codec)

This mimicks the current signatures of NodeStoreDisk and NodeStoreMemory, which
include the use of allow_writes as first parameter, and which seem required
to actually create a forest anyway since forest.py creates node_store instances 
with allow_writes as first parameter in open_forest

8 files changed, 26 insertions, 21 deletions

diff --git a/example.py b/example.py
index 53864c9..c6bce64 100644
--- a/example.py
+++ b/example.py
@@ -33,11 +33,11 @@ def compute(filename):
     return md5.hexdigest()
 
 
-def open_tree(dirname):
+def open_tree(allow_writes, dirname):
     key_size = len(compute('/dev/null'))
     node_size = 4096
     
-    forest = larch.open_forest(key_size=key_size, node_size=node_size,
+    forest = larch.open_forest(allow_writes=allow_writes, key_size=key_size, node_size=node_size,
                                dirname=dirname)
     if forest.trees:
         tree = forest.trees[0]
@@ -47,7 +47,7 @@ def open_tree(dirname):
 
 
 def add(filenames):
-    forest, tree = open_tree('example.tree')
+    forest, tree = open_tree(allow_writes=True, dirname='example.tree')
     for filename in filenames:
         checksum = compute(filename)
         tree.insert(checksum, filename)
@@ -55,17 +55,17 @@ def add(filenames):
 
 
 def find(checksums):
-    forest, tree = open_tree('example.tree')
+    forest, tree = open_tree(allow_writes=False, dirname='example.tree')
     for checksum in checksums:
         filename = tree.lookup(checksum)
         print checksum, filename
 
 
 def list_checksums():
-    forest, tree = open_tree('example.tree')
+    forest, tree = open_tree(allow_writes=False, dirname='example.tree')
     key_size = len(compute('/dev/null'))
-    minkey = '00' * key_size
-    maxkey = 'ff' * key_size
+    minkey = '0' * key_size
+    maxkey = 'f' * key_size
     for checksum, filename in tree.lookup_range(minkey, maxkey):
         print checksum, filename
 
diff --git a/larch/forest_tests.py b/larch/forest_tests.py
index 9a786bd..a7c9677 100644
--- a/larch/forest_tests.py
+++ b/larch/forest_tests.py
@@ -26,7 +26,7 @@ class ForestTests(unittest.TestCase):
 
     def setUp(self):
         self.codec = larch.NodeCodec(3)
-        self.ns = larch.NodeStoreMemory(64, self.codec)
+        self.ns = larch.NodeStoreMemory(allow_writes=True, node_size=64, codec=self.codec)
         self.forest = larch.Forest(self.ns)
 
     def test_new_node_ids_grow(self):
diff --git a/larch/nodestore.py b/larch/nodestore.py
index 929450a..dd9b536 100644
--- a/larch/nodestore.py
+++ b/larch/nodestore.py
@@ -98,7 +98,8 @@ class NodeStore(object): # pragma: no cover
     
     '''
     
-    def __init__(self, node_size, codec):
+    def __init__(self, allow_writes, node_size, codec):
+        self.allow_writes = allow_writes
         self.node_size = node_size
         self.codec = codec
         self.max_value_size = (node_size / 2) - codec.leaf_header.size
diff --git a/larch/nodestore_disk.py b/larch/nodestore_disk.py
index 197a411..3cb8ee7 100644
--- a/larch/nodestore_disk.py
+++ b/larch/nodestore_disk.py
@@ -117,7 +117,7 @@ class NodeStoreDisk(larch.NodeStore):
         if format is not None:
             tracing.trace('forcing format_base: %s', format)
             self.format_base = format
-        larch.NodeStore.__init__(self, node_size, codec)
+        larch.NodeStore.__init__(self, allow_writes=allow_writes, node_size=node_size, codec=codec)
         self.dirname = dirname
         self.metadata_name = os.path.join(dirname, 'metadata')
         self.metadata = None
diff --git a/larch/nodestore_memory.py b/larch/nodestore_memory.py
index 510ce5e..f0598be 100644
--- a/larch/nodestore_memory.py
+++ b/larch/nodestore_memory.py
@@ -26,8 +26,8 @@ class NodeStoreMemory(larch.NodeStore):
     
     '''
     
-    def __init__(self, node_size, codec):
-        larch.NodeStore.__init__(self, node_size, codec)
+    def __init__(self,allow_writes, node_size, codec):
+        larch.NodeStore.__init__(self, allow_writes=allow_writes, node_size=node_size, codec=codec)
         self.nodes = dict()
         self.refcounts = dict()
         self.metadata = dict()
diff --git a/larch/nodestore_memory_tests.py b/larch/nodestore_memory_tests.py
index eecb905..8c210db 100644
--- a/larch/nodestore_memory_tests.py
+++ b/larch/nodestore_memory_tests.py
@@ -25,5 +25,5 @@ class NodeStoreMemoryTests(unittest.TestCase, larch.NodeStoreTests):
     def setUp(self):
         self.node_size = 4096
         self.codec = larch.NodeCodec(self.key_bytes)
-        self.ns = nodestore_memory.NodeStoreMemory(self.node_size, self.codec)
+        self.ns = nodestore_memory.NodeStoreMemory(allow_writes=True, node_size=self.node_size, codec=self.codec)
 
diff --git a/larch/tree_tests.py b/larch/tree_tests.py
index 86895f0..8a4a4e9 100644
--- a/larch/tree_tests.py
+++ b/larch/tree_tests.py
@@ -67,7 +67,7 @@ class BTreeTests(unittest.TestCase):
         # We use a small node size so that all code paths are traversed
         # during testing. Use coverage.py to make sure they do.
         self.codec = larch.NodeCodec(3)
-        self.ns = DummyNodeStore(64, self.codec)
+        self.ns = DummyNodeStore(allow_writes=True, node_size=64, codec=self.codec)
         self.forest = DummyForest()
         self.tree = larch.BTree(self.forest, self.ns, None)
         self.dump = False
@@ -549,7 +549,7 @@ class BTreeDecrementTests(unittest.TestCase):
         # We use a small node size so that all code paths are traversed
         # during testing. Use coverage.py to make sure they do.
         self.codec = larch.NodeCodec(3)
-        self.ns = DummyNodeStore(64, self.codec)
+        self.ns = DummyNodeStore(allow_writes=True, node_size=64, codec=self.codec)
         self.forest = DummyForest()
         self.tree = larch.BTree(self.forest, self.ns, None)
         self.tree.insert('foo', 'bar')
@@ -574,7 +574,7 @@ class BTreeDecrementTests(unittest.TestCase):
 class BTreeBalanceTests(unittest.TestCase):
 
     def setUp(self):
-        ns = DummyNodeStore(4096, larch.NodeCodec(2))
+        ns = DummyNodeStore(allow_writes=True, node_size=4096, codec=larch.NodeCodec(2))
         forest = DummyForest()
         self.tree = larch.BTree(forest, ns, None)
         self.keys = ['%02d' % i for i in range(10)]
diff --git a/speed-test b/speed-test
index 5351a82..4d6ffab 100755
--- a/speed-test
+++ b/speed-test
@@ -15,8 +15,8 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Excercise my B-tree implementation, for simple benchmarking purposes.
-# The benchmark gets a location and an operation count as command line
-# arguments.
+# The benchmark gets a location and nb of keys to use as command line
+# arguments --location=LOCATION and --keys=KEYS.
 #
 # If the location is the empty string, an in-memory node store is used.
 # Otherwise it must be a non-existent directory name.
@@ -73,13 +73,13 @@ class SpeedTest(cliapp.Application):
             raise Exception('You must set number of keys with --keys')
         
         if not location:
-            forest = larch.open_forest(key_size=key_size, node_size=node_size,
+            forest = larch.open_forest(allow_writes=True, key_size=key_size, node_size=node_size,
                                        node_store=larch.NodeStoreMemory)
         else:
             if os.path.exists(location):
                 raise Exception('%s exists already' % location)
             os.mkdir(location)
-            forest = larch.open_forest(key_size=key_size, node_size=node_size,
+            forest = larch.open_forest(allow_writes=True, key_size=key_size, node_size=node_size,
                                        dirname=location)
 
         tree = forest.new_tree()
@@ -144,7 +144,11 @@ class SpeedTest(cliapp.Application):
 
         # Report
         def speed(result, i):
-            return n / (result[i] - looptime[i])
+            if result[i] == looptime[i]:
+                # computer too fast for the number of "keys" used...
+                return float("infinity")
+            else:
+                return n / (result[i] - looptime[i])
         def report(label, result):
             cpu, wall = result
             print '%-16s: %5.3f s (%8.1f/s) CPU; %5.3f s (%8.1f/s) wall' % \