Extensions Docs Server: Uniform handling of file not found errors

chrome/common/extensions/docs/server2/local_file_system.py

 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import os
 
 import file_system
 from future import Future
 
 class LocalFileSystem(file_system.FileSystem):
   """FileSystem implementation which fetches resources from the local
   filesystem.
   """
   def __init__(self, base_path):
     self._base_path = self._ConvertToFilepath(base_path)
 
   def _ConvertToFilepath(self, path):
     return path.replace('/', os.sep)
 
   def _ReadFile(self, filename, binary):
-    with open(os.path.join(self._base_path, filename), 'r') as f:
-      contents = f.read()
-      if binary:
-        return contents
-      return file_system._ProcessFileData(contents, filename)
+    try:
+      with open(os.path.join(self._base_path, filename), 'r') as f:
+        contents = f.read()
+        if binary:
+          return contents
+        return file_system._ProcessFileData(contents, filename)
+    except IOError:

[not at google - send to devlin, 2012/08/10 06:12:16]

why IOError here and OSError other times? Python quirk?

[cduvall, 2012/08/10 17:25:16]

Yep, os.listdir throws OSError, but open throws IOError.

+      raise file_system.FileNotFoundError(filename)
 
   def _ListDir(self, dir_name):
     all_files = []
     full_path = os.path.join(self._base_path, dir_name)
-    for path in os.listdir(full_path):
+    try:
+      files = os.listdir(full_path)
+    except OSError:
+      raise file_system.FileNotFoundError(dir_name)
+    for path in files:
       if path.startswith('.'):
         continue
       if os.path.isdir(os.path.join(full_path, path)):
         all_files.append(path + '/')
       else:
         all_files.append(path)
     return all_files
 
   def Read(self, paths, binary=False):
     result = {}
     for path in paths:
       if path.endswith('/'):
         result[path] = self._ListDir(self._ConvertToFilepath(path))
       else:
         result[path] = self._ReadFile(self._ConvertToFilepath(path), binary)
     return Future(value=result)
 
   def Stat(self, path):
-    return self.StatInfo(os.stat(os.path.join(self._base_path, path)).st_mtime)
+    try:
+      return self.StatInfo(
+          os.stat(os.path.join(self._base_path, path)).st_mtime)
+    except OSError:
+      raise file_system.FileNotFoundError(path)
+