1 files changed, 60 insertions, 0 deletions
diff --git a/libs/python/pyste/src/Pyste/SmartFile.py b/libs/python/pyste/src/Pyste/SmartFile.py
new file mode 100644
index 000000000..039579e3b
--- /dev/null
+++ b/libs/python/pyste/src/Pyste/SmartFile.py
@@ -0,0 +1,60 @@
+# Copyright Bruno da Silva de Oliveira 2003. Use, modification and 
+# distribution is subject to the Boost Software License, Version 1.0.
+# (See accompanying file LICENSE_1_0.txt or copy at 
+# http://www.boost.org/LICENSE_1_0.txt)
+
+import os
+import md5
+
+#==============================================================================
+# SmartFile
+#==============================================================================
+class SmartFile(object):
+    '''
+    A file-like object used for writing files. The given file will only be
+    actually written to disk if there's not a file with the same name, or if
+    the existing file is *different* from the file to be written.
+    '''
+
+    def __init__(self, filename, mode='w'):
+        self.filename = filename
+        self.mode = mode
+        self._contents = []
+        self._closed = False
+
+
+    def __del__(self):
+        if not self._closed:
+            self.close()
+
+
+    def write(self, string):
+        self._contents.append(string)
+
+
+    def _dowrite(self, contents):
+        f = file(self.filename, self.mode)
+        f.write(contents)
+        f.close()
+        
+        
+    def _GetMD5(self, string):
+        return md5.new(string).digest()
+        
+    
+    def close(self):
+        # if the filename doesn't exist, write the file right away
+        this_contents = ''.join(self._contents)
+        if not os.path.isfile(self.filename):
+            self._dowrite(this_contents)
+        else:
+            # read the contents of the file already in disk
+            f = file(self.filename)
+            other_contents = f.read()
+            f.close()
+            # test the md5 for both files 
+            this_md5 = self._GetMD5(this_contents)
+            other_md5 = self._GetMD5(other_contents)
+            if this_md5 != other_md5:
+                self._dowrite(this_contents)
+        self._closed = True