Moving away from shell api to support long path names on windows for filesystem.

base/file_util_win.cc

 // Copyright (c) 2010 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.
 
 #include "base/file_util.h"
 
 #include <windows.h>
 #include <propvarutil.h>
 #include <psapi.h>
 #include <shellapi.h>
@@ skipping 111 matching lines @@
       // File was created after or on comparison time
       if ((result == 1) || (result == 0))
         ++file_count;
     } while (FindNextFile(find_handle,  &find_file_data));
     FindClose(find_handle);
   }
 
   return file_count;
 }
 
+// Callers of Delete can call with extended path prefix and with path lengths
+// greater than 260.

[kinuko, 2010/12/15 00:09:30]

Can we put this comment (maybe in a simpler form, like 'this method is
extended-path safe on Windows') for all the methods that support extended paths?
Also I think it'd be better to put the comment in the header file.

[Kavita Kanetkar, 2010/12/16 00:48:55]

Done.

 bool Delete(const FilePath& path, bool recursive) {
   base::ThreadRestrictions::AssertIOAllowed();
 
-  if (path.value().length() >= MAX_PATH)
-    return false;
+  base::PlatformFileInfo file_info;
+  if (!GetFileInfo(path, &file_info))
+    return true;
 
-  if (!recursive) {
-    // If not recursing, then first check to see if |path| is a directory.
-    // If it is, then remove it with RemoveDirectory.
-    base::PlatformFileInfo file_info;
-    if (GetFileInfo(path, &file_info) && file_info.is_directory)
-      return RemoveDirectory(path.value().c_str()) != 0;
+  if (!file_info.is_directory)
+    return (DeleteFile(path.value().c_str()) != 0);
 
-    // Otherwise, it's a file, wildcard or non-existant. Try DeleteFile first
-    // because it should be faster. If DeleteFile fails, then we fall through
-    // to SHFileOperation, which will do the right thing.
-    if (DeleteFile(path.value().c_str()) != 0)
-      return true;
+  if (!recursive)
+    return RemoveDirectory(path.value().c_str()) != 0;
+
+  // Matches posix version of iterating directories.
+  bool success = true;
+  std::stack<FilePath::StringType> directories;
+  directories.push(path.value());
+  FileEnumerator traversal(path, true, static_cast<FileEnumerator::FILE_TYPE>(
+      FileEnumerator::FILES | FileEnumerator::DIRECTORIES));
+
+  for (FilePath current = traversal.Next(); success && !current.empty();
+       current = traversal.Next()) {
+    FileEnumerator::FindInfo info;
+    traversal.GetFindInfo(&info);
+    if (traversal.IsDirectory(info)) {
+      directories.push(current.value());
+    } else {
+    // This is needed because DeleteFile can fail for read-only files.

[kinuko, 2010/12/15 00:09:30]

nit: indentation (in this block)

[Kavita Kanetkar, 2010/12/16 00:48:55]

Done.

+    uint32 attributes = ::GetFileAttributes(current.value().c_str());
+    if (attributes != INVALID_FILE_ATTRIBUTES &&

[kinuko, 2010/12/15 00:09:30]

If it's INVALID_FILE_ATTRIBUTES the following DeleteFile will fail anyway?
Should we exit early?

[Kavita Kanetkar, 2010/12/16 00:48:55]

I thought about it but I feel it's ok to let Delete fail.

On 2010/12/15 00:09:30, kinuko wrote:

+        attributes &~ FILE_ATTRIBUTE_READONLY)

[kinuko, 2010/12/15 00:09:30]

um, you'd want to keep this '&'

+      ::SetFileAttributes(current.value().c_str(), FILE_ATTRIBUTE_NORMAL);

[kinuko, 2010/12/15 00:09:30]

and replace this FILE_ATTRIBUTE_NORMAL with (attributes &~
FILE_ATTRIBUTE_READONLY).

[Kavita Kanetkar, 2010/12/16 00:48:55]

Oops yes.

On 2010/12/15 00:09:30, kinuko wrote:

+    success = (DeleteFile(current.value().c_str()) != 0);
+    }
   }
 
-  // SHFILEOPSTRUCT wants the path to be terminated with two NULLs,
-  // so we have to use wcscpy because wcscpy_s writes non-NULLs
-  // into the rest of the buffer.
-  wchar_t double_terminated_path[MAX_PATH + 1] = {0};
-#pragma warning(suppress:4996)  // don't complain about wcscpy deprecation
-  wcscpy(double_terminated_path, path.value().c_str());
-
-  SHFILEOPSTRUCT file_operation = {0};
-  file_operation.wFunc = FO_DELETE;
-  file_operation.pFrom = double_terminated_path;
-  file_operation.fFlags = FOF_NOERRORUI | FOF_SILENT | FOF_NOCONFIRMATION;
-  if (!recursive)
-    file_operation.fFlags |= FOF_NORECURSION | FOF_FILESONLY;
-  int err = SHFileOperation(&file_operation);
-  // Some versions of Windows return ERROR_FILE_NOT_FOUND (0x2) when deleting
-  // an empty directory and some return 0x402 when they should be returning
-  // ERROR_FILE_NOT_FOUND. MSDN says Vista and up won't return 0x402.
-  return (err == 0 || err == ERROR_FILE_NOT_FOUND || err == 0x402);
+  while (success && !directories.empty()) {
+    FilePath dir = FilePath(directories.top());
+    directories.pop();
+    success = (RemoveDirectory(dir.value().c_str()) != 0);
+  }
+  return success;
 }
 
 bool DeleteAfterReboot(const FilePath& path) {
   base::ThreadRestrictions::AssertIOAllowed();
 
   if (path.value().length() >= MAX_PATH)
     return false;
 
   return MoveFileEx(path.value().c_str(), NULL,
                     MOVEFILE_DELAY_UNTIL_REBOOT |
@@ skipping 38 matching lines @@
   // When writing to a network share, we may not be able to change the ACLs.
   // Ignore ACL errors then (REPLACEFILE_IGNORE_MERGE_ERRORS).
   return ::ReplaceFile(to_path.value().c_str(),
       from_path.value().c_str(), NULL,
       REPLACEFILE_IGNORE_MERGE_ERRORS, NULL, NULL) ? true : false;
 }
 
 bool CopyFile(const FilePath& from_path, const FilePath& to_path) {
   base::ThreadRestrictions::AssertIOAllowed();
 
-  // NOTE: I suspect we could support longer paths, but that would involve
-  // analyzing all our usage of files.
-  if (from_path.value().length() >= MAX_PATH ||
-      to_path.value().length() >= MAX_PATH) {
-    return false;
-  }
   return (::CopyFile(from_path.value().c_str(), to_path.value().c_str(),
                      false) != 0);
 }
 
-bool ShellCopy(const FilePath& from_path, const FilePath& to_path,
-               bool recursive) {
-  base::ThreadRestrictions::AssertIOAllowed();
-
-  // NOTE: I suspect we could support longer paths, but that would involve
-  // analyzing all our usage of files.
-  if (from_path.value().length() >= MAX_PATH ||
-      to_path.value().length() >= MAX_PATH) {
-    return false;
-  }
-
-  // SHFILEOPSTRUCT wants the path to be terminated with two NULLs,
-  // so we have to use wcscpy because wcscpy_s writes non-NULLs
-  // into the rest of the buffer.
-  wchar_t double_terminated_path_from[MAX_PATH + 1] = {0};
-  wchar_t double_terminated_path_to[MAX_PATH + 1] = {0};
-#pragma warning(suppress:4996)  // don't complain about wcscpy deprecation
-  wcscpy(double_terminated_path_from, from_path.value().c_str());
-#pragma warning(suppress:4996)  // don't complain about wcscpy deprecation
-  wcscpy(double_terminated_path_to, to_path.value().c_str());
-
-  SHFILEOPSTRUCT file_operation = {0};
-  file_operation.wFunc = FO_COPY;
-  file_operation.pFrom = double_terminated_path_from;
-  file_operation.pTo = double_terminated_path_to;
-  file_operation.fFlags = FOF_NOERRORUI | FOF_SILENT | FOF_NOCONFIRMATION |
-                          FOF_NOCONFIRMMKDIR;
-  if (!recursive)
-    file_operation.fFlags |= FOF_NORECURSION | FOF_FILESONLY;
-
-  return (SHFileOperation(&file_operation) == 0);
-}
-
+// CopyDirectory works for windows extended path lengths that are greater than
+// 260. Such paths are prefixed.
 bool CopyDirectory(const FilePath& from_path, const FilePath& to_path,
                    bool recursive) {
   base::ThreadRestrictions::AssertIOAllowed();
+  FilePath real_to_path = to_path;
+  if (PathExists(real_to_path)) {
+      if (!real_to_path.StartsWithExtendedPathPrefix() &&

[kinuko, 2010/12/15 00:09:30]

nit: indentation

[Kavita Kanetkar, 2010/12/16 00:48:55]

Done.

+          !AbsolutePath(&real_to_path))
+      return false;
+  } else {
+    real_to_path = real_to_path.DirName();
+    if (!real_to_path.StartsWithExtendedPathPrefix() &&
+        !AbsolutePath(&real_to_path))
+      return false;
+  }
+  FilePath real_from_path = from_path;
+  if (!real_from_path.StartsWithExtendedPathPrefix() &&
+      !AbsolutePath(&real_from_path))
+    return false;
+  if (real_to_path.value().size() >= real_from_path.value().size() &&
+      real_to_path.value().compare(0, real_from_path.value().size(),
+      real_from_path.value()) == 0)
+    return false;
 
+  bool success = true;
+  FileEnumerator::FILE_TYPE traverse_type =
+      static_cast<FileEnumerator::FILE_TYPE>(FileEnumerator::FILES);
   if (recursive)
-    return ShellCopy(from_path, to_path, true);
+    traverse_type = static_cast<FileEnumerator::FILE_TYPE>(
+        traverse_type | FileEnumerator::DIRECTORIES);
+  FileEnumerator traversal(from_path, recursive, traverse_type);
 
-  // The following code assumes that from path is a directory.
-  DCHECK(DirectoryExists(from_path));
-
-  // Instead of creating a new directory, we copy the old one to include the
-  // security information of the folder as part of the copy.
-  if (!PathExists(to_path)) {
-    // Except that Vista fails to do that, and instead do a recursive copy if
-    // the target directory doesn't exist.
-    if (base::win::GetVersion() >= base::win::VERSION_VISTA)
-      CreateDirectory(to_path);
-    else
-      ShellCopy(from_path, to_path, false);
+  // |to_path| may not exist yet, start the loop with |to_path|.
+  FilePath current = from_path;
+  if (!PathExists(from_path)) {
+    LOG(ERROR) << "CopyDirectory() couldn't get info on source directory: "
+               << from_path.value();
+    success = false;
   }
 
-  FilePath directory = from_path.Append(L"*.*");
-  return ShellCopy(directory, to_path, false);
+  FilePath from_path_base = from_path;
+  if (recursive && DirectoryExists(to_path)) {
+    // If the destination already exists and is a directory, then the
+    // top level of source needs to be copied.
+    from_path_base = from_path.DirName();
+  }
+  DCHECK(recursive || DirectoryExists(from_path));

[kinuko, 2010/12/15 00:09:30]

Now we may want some comment here (as we do in file_util_posix) explaining why
we DCHECK here?

[Kavita Kanetkar, 2010/12/16 00:48:55]

Done.

+  while (success && !current.empty()) {
+    // current is the source path, including from_path, so paste
+    // the suffix after from_path onto to_path to create the target_path.
+    FilePath::StringType suffix(
+        &current.value().c_str()[from_path_base.value().size()]);
+    // Strip the leading '\' (if any).
+    if (!suffix.empty()) {
+      DCHECK_EQ('\\', suffix[0]);
+      suffix.erase(0, 1);
+    }
+    const FilePath target_path = to_path.Append(suffix);
+
+    if (DirectoryExists(current)) {
+      if (::CreateDirectory(target_path.value().c_str(), NULL) == 0) {
+        if (!DirectoryExists(target_path)) {
+          LOG(ERROR) << "CopyDirectory() couldn't create directory: "
+                     << target_path.value();
+          success = false;
+        }
+      }
+    } else {
+      if (!CopyFile(current, target_path)) {
+        LOG(ERROR) << "CopyDirectory() couldn't create file: "
+                   << target_path.value();
+        success = false;
+      }
+    }
+    current = traversal.Next();
+  }
+  return success;

[kinuko, 2010/12/15 00:09:30]

I really wonder if we could just have this one in file_util.cc and deprecate
file_util_posix's implementation.  The whole logic is not very simple and having
duplicated code here and there is very unfortunate.
We can use FilePath::kSeparators for the path separator, and make
StartsWithExtendedPathPrefix() just returns false for non-windows
implementation.
(And same for Delete.  Though we need to hide or separate out attribute checks
to make it work for all platforms.)

 }
 
 bool CopyAndDeleteDirectory(const FilePath& from_path,
                             const FilePath& to_path) {
   base::ThreadRestrictions::AssertIOAllowed();
   if (CopyDirectory(from_path, to_path, true)) {
     if (Delete(from_path, true)) {
       return true;
     }
     // Like Move, this function is not transactional, so we just
     // leave the copied bits behind if deleting from_path fails.
     // If to_path exists previously then we have already overwritten
     // it by now, we don't get better off by deleting the new bits.
   }
   return false;
 }
 
-
 bool PathExists(const FilePath& path) {
   base::ThreadRestrictions::AssertIOAllowed();
   return (GetFileAttributes(path.value().c_str()) != INVALID_FILE_ATTRIBUTES);
 }
 
 bool PathIsWritable(const FilePath& path) {
   base::ThreadRestrictions::AssertIOAllowed();
   HANDLE dir =
       CreateFile(path.value().c_str(), FILE_ADD_FILE, kFileShareAll,
                  NULL, OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS, NULL);
@@ skipping 803 matching lines @@
       uint8 unused = *(touch + offset);
       offset += step_size;
     }
     FreeLibrary(dll_module);
   }
 
   return true;
 }
 
 }  // namespace file_util