A robust base::DeleteFile.

base/files/file_util.h

 // 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.
 
 // This file contains utility functions for dealing with the local
 // filesystem.
 
 #ifndef BASE_FILES_FILE_UTIL_H_
 #define BASE_FILES_FILE_UTIL_H_
 
@@ skipping 37 matching lines @@
 // function can result in I/O so it can be slow.
 BASE_EXPORT FilePath MakeAbsoluteFilePath(const FilePath& input);
 
 // Returns the total number of bytes used by all the files under |root_path|.
 // If the path does not exist the function returns 0.
 //
 // This function is implemented using the FileEnumerator class so it is not
 // particularly speedy in any platform.
 BASE_EXPORT int64_t ComputeDirectorySize(const FilePath& root_path);
 
-// Deletes the given path, whether it's a file or a directory.
-// If it's a directory, it's perfectly happy to delete all of the
-// directory's contents.  Passing true to recursive deletes
-// subdirectories and their contents as well.
-// Returns true if successful, false otherwise. It is considered successful
-// to attempt to delete a file that does not exist.
+// Deletes the given path. If |path| names a directory and |recursive| is false,
+// the directory is only deleted if it is empty or is a symbolic link. If |path|
+// names a directory and |recursive| is true, this function will recursively
+// delete as much as possible within |path|, ideally ending in success when
+// |path| is deleted. In case of error, an unspecified amount of |path|'s
+// original contents may already have been deleted. On Windows, as much as
+// possible will always be deleted. Returns true if |path| was deleted or did

[Sigurður Ásgeirsson, 2016/12/08 14:36:46]

maybe some words that this is constrained to a single volume?

[grt (UTC plus 2), 2016/12/08 20:35:16]

Done.

+// not exist.
 //
-// In posix environment and if |path| is a symbolic link, this deletes only
-// the symlink. (even if the symlink points to a non-existent file)
+// In posix environment and if |path| is a symbolic link, this deletes only the
+// symlink. (even if the symlink points to a non-existent file)
 //
 // WARNING: USING THIS WITH recursive==true IS EQUIVALENT
 //          TO "rm -rf", SO USE WITH CAUTION.
 BASE_EXPORT bool DeleteFile(const FilePath& path, bool recursive);
 
 #if defined(OS_WIN)
+struct DeleteFileMetrics {

[Sigurður Ásgeirsson, 2016/12/08 14:36:46]

nice and simple, I like it.

[grt (UTC plus 2), 2016/12/08 20:35:16]

Thanks.

+  enum TemporaryDirectoryLocation {
+    UNDECIDED,    // No attempt has yet been made to find a directory.
+    NONE,         // Failed to find a writeable temporary directory.
+    TEMP,         // Using %TEMP%.
+    VOLUME_TEMP,  // Using X:\Temp or X:\Tmp.
+    PARENT,       // Using the directory above the top-most item being deleted.
+    ITEM,         // Using the directory containing the item being deleted.
+  };
+
+  TemporaryDirectoryLocation temporary_directory_location;
+
+  // The number of items deleted via the DELETE_ON_CLOSE path.
+  int delete_on_close_success_count;
+
+  // The number of items in |delete_on_close_success_count| that were moved into
+  // the temp directory. Ideally, this equals |delete_on_close_success_count|,
+  // meaning that the operation was 100% successful.
+  int move_to_temp_count;
+
+  // The number of times opening an item to be deleted failed, resulting in a
+  // fallback to plain ::DeleteFile that succeded.
+  int delete_file_success_count;
+
+  // The number of times each of the above strategies failed to delete an item.
+  int fail_count;
+
+  // The total number of retries before giving up (0 if success on the first
+  // attempt). If the overall operation succeeds and this is not zero, the
+  // retries were a very good thing. If the overall operation fails and the two
+  // success counts above are non-zero, then perhaps more retries or some delays
+  // would have helped. If the overall operation fails and the two success
+  // counts above are zero, then it's likely that nothing would have helped.
+  int total_retry_count;
+
+  // The maximum recursion depth.
+  int max_depth;
+};
+
+// The same as DeleteFile, but with metrics about its performance.
+BASE_EXPORT bool DeleteFileWithMetrics(const FilePath& path,
+                                       bool recursive,
+                                       DeleteFileMetrics* metrics);
+
 // Schedules to delete the given path, whether it's a file or a directory, until
 // the operating system is restarted.
 // Note:
 // 1) The file/directory to be deleted should exist in a temp folder.
 // 2) The directory to be deleted must be empty.
 BASE_EXPORT bool DeleteFileAfterReboot(const FilePath& path);
 #endif
 
 // Moves the given path, whether it's a file or a directory.
 // If a simple rename is not possible, such as in the case where the paths are
@@ skipping 365 matching lines @@
 // This function simulates Move(), but unlike Move() it works across volumes.
 // This function is not transactional.
 BASE_EXPORT bool CopyAndDeleteDirectory(const FilePath& from_path,
                                         const FilePath& to_path);
 #endif  // defined(OS_WIN)
 
 }  // namespace internal
 }  // namespace base
 
 #endif  // BASE_FILES_FILE_UTIL_H_