split up util.py into files.py and logger.py, moved code appropriately

overviewer_core/files.py

@@ -0,0 +1,122 @@
+#    This file is part of the Minecraft Overviewer.
+#
+#    Minecraft Overviewer 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.
+#
+#    Minecraft Overviewer 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 the Overviewer.  If not, see <http://www.gnu.org/licenses/>.
+
+import os
+import os.path
+import tempfile
+import shutil
+import logging
+
+## useful recursive copy, that ignores common OS cruft
+def mirror_dir(src, dst, entities=None):
+    '''copies all of the entities from src to dst'''
+    if not os.path.exists(dst):
+        os.mkdir(dst)
+    if entities and type(entities) != list: raise Exception("Expected a list, got a %r instead" % type(entities))
+    
+    # files which are problematic and should not be copied
+    # usually, generated by the OS
+    skip_files = ['Thumbs.db', '.DS_Store']
+    
+    for entry in os.listdir(src):
+        if entry in skip_files:
+            continue
+        if entities and entry not in entities:
+            continue
+        
+        if os.path.isdir(os.path.join(src,entry)):
+            mirror_dir(os.path.join(src, entry), os.path.join(dst, entry))
+        elif os.path.isfile(os.path.join(src,entry)):
+            try:
+                shutil.copy(os.path.join(src, entry), os.path.join(dst, entry))
+            except IOError as outer: 
+                try:
+                    # maybe permission problems?
+                    src_stat = os.stat(os.path.join(src, entry))
+                    os.chmod(os.path.join(src, entry), src_stat.st_mode | stat.S_IRUSR)
+                    dst_stat = os.stat(os.path.join(dst, entry))
+                    os.chmod(os.path.join(dst, entry), dst_stat.st_mode | stat.S_IWUSR)
+                except OSError: # we don't care if this fails
+                    pass
+                shutil.copy(os.path.join(src, entry), os.path.join(dst, entry))
+                # if this stills throws an error, let it propagate up
+
+# Define a context manager to handle atomic renaming or "just forget it write
+# straight to the file" depending on whether os.rename provides atomic
+# overwrites.
+# Detect whether os.rename will overwrite files
+with tempfile.NamedTemporaryFile() as f1:
+    with tempfile.NamedTemporaryFile() as f2:
+        try:
+            os.rename(f1.name,f2.name)
+        except OSError:
+            renameworks = False
+        else:
+            renameworks = True
+            # re-make this file so it can be deleted without error
+            open(f1.name, 'w').close()
+del tempfile,f1,f2
+doc = """This class acts as a context manager for files that are to be written
+out overwriting an existing file.
+
+The parameter is the destination filename. The value returned into the context
+is the filename that should be used. On systems that support an atomic
+os.rename(), the filename will actually be a temporary file, and it will be
+atomically replaced over the destination file on exit.
+
+On systems that don't support an atomic rename, the filename returned is the
+filename given.
+
+If an error is encountered, the file is attempted to be removed, and the error
+is propagated.
+
+Example:
+
+with FileReplacer("config") as configname:
+    with open(configout, 'w') as configout:
+        configout.write(newconfig)
+"""
+if renameworks:
+    class FileReplacer(object):
+        __doc__ = doc
+        def __init__(self, destname):
+            self.destname = destname
+            self.tmpname = destname + ".tmp"
+        def __enter__(self):
+            # rename works here. Return a temporary filename
+            return self.tmpname
+        def __exit__(self, exc_type, exc_val, exc_tb):
+            if exc_type:
+                # error
+                try:
+                    os.remove(self.tmpname)
+                except Exception, e:
+                    logging.warning("An error was raised, so I was doing "
+                            "some cleanup first, but I couldn't remove "
+                            "'%s'!", self.tmpname)
+            else:
+                # atomic rename into place
+                os.rename(self.tmpname, self.destname)
+else:
+    class FileReplacer(object):
+        __doc__ = doc
+        def __init__(self, destname):
+            self.destname = destname
+        def __enter__(self):
+            return self.destname
+        def __exit__(self, exc_type, exc_val, exc_tb):
+            return
+del renameworks
+