extract BlockHasher and TreeHasher classes

zfs_autobackup/TreeHasher.py

@@ -0,0 +1,33 @@
+import os
+
+
+class TreeHasher():
+    """uses BlockHasher recursively on a directory tree"""
+
+    def __init__(self, block_hasher):
+        self.block_hasher=block_hasher
+
+    def generate(self, start_path):
+        """Use BlockHasher on every file in a tree, yielding the results
+
+        note that it only checks the contents of actual files. It ignores metadata like permissions and mtimes.
+        It also ignores empty directories, symlinks and special files.
+        """
+
+        cwd=os.getcwd()
+        os.chdir(start_path)
+
+        def walkerror(e):
+            raise e
+
+        try:
+            for (dirpath, dirnames, filenames) in os.walk(".", onerror=walkerror):
+                for f in filenames:
+                    file_path=os.path.join(dirpath, f)[2:]
+
+                    if (not os.path.islink(file_path)) and os.path.isfile(file_path):
+                        for (chunk_nr, hash) in self.block_hasher.generate(file_path):
+                            yield ( file_path, chunk_nr, hash )
+        finally:
+            os.chdir(cwd)
+