Make CopyDirectory() not copy the read only bit on Windows.

base/file_util_win.cc

Index: base/file_util_win.cc
diff --git a/base/file_util_win.cc b/base/file_util_win.cc
index dd6282516e4f0a1888ac56da826476898bd9e758..98b29eb84c8295afc45b98a76caf6cabf4f1cad8 100644
--- a/base/file_util_win.cc
+++ b/base/file_util_win.cc
@@ -14,6 +14,7 @@
 #include <limits>
 #include <string>
 
+#include "base/files/file_enumerator.h"
 #include "base/files/file_path.h"
 #include "base/logging.h"
 #include "base/metrics/histogram.h"
@@ -34,44 +35,6 @@ namespace {
 const DWORD kFileShareAll =
     FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE;
 
-bool ShellCopy(const FilePath& from_path,
-               const FilePath& to_path,
-               bool recursive) {
-  // WinXP SHFileOperation doesn't like trailing separators.
-  FilePath stripped_from = from_path.StripTrailingSeparators();
-  FilePath stripped_to = to_path.StripTrailingSeparators();
-
-  ThreadRestrictions::AssertIOAllowed();
-
-  // NOTE: I suspect we could support longer paths, but that would involve
-  // analyzing all our usage of files.
-  if (stripped_from.value().length() >= MAX_PATH ||
-      stripped_to.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, stripped_from.value().c_str());
-#pragma warning(suppress:4996)  // don't complain about wcscpy deprecation
-  wcscpy(double_terminated_path_to, stripped_to.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);
-}
-
 }  // namespace
 
 FilePath MakeAbsoluteFilePath(const FilePath& input) {
@@ -164,27 +127,92 @@ bool ReplaceFile(const FilePath& from_path,
 
 bool CopyDirectory(const FilePath& from_path, const FilePath& to_path,
                    bool recursive) {
+  // NOTE(maruel): Previous version of this function used to call
+  // SHFileOperation().  This used to copy the file attributes and extended
+  // attributes, OLE structured storage, NTFS file system alternate data
+  // streams, SECURITY_DESCRIPTOR. In practice, this is not what we want, we
+  // want the containing directory to propagate its SECURITY_DESCRIPTOR.
   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;
+  }
+
+  // This function does not properly handle destinations within the source

[grt (UTC plus 2), 2014/01/24 20:50:07]

nit: period at end of sentence

[M-A Ruel, 2014/01/24 21:32:57]

Done.

+  FilePath real_to_path = to_path;
+  if (PathExists(real_to_path)) {

[grt (UTC plus 2), 2014/01/24 20:50:07]

do the existing unittests cover all of these cases?

[M-A Ruel, 2014/01/24 21:32:57]

In FileUtilTest,
- CopyDirectoryRecursivelyNew
- CopyDirectoryRecursivelyExists
- CopyDirectoryNew
- CopyDirectoryExists
- CopyFileWithCopyDirectoryRecursiveToNew
- CopyFileWithCopyDirectoryRecursiveToExisting
- CopyFileWithCopyDirectoryRecursiveToExistingDirectory
- CopyDirectoryWithTrailingSeparators
- CopyDirectoryACL

does most of them.

+    real_to_path = MakeAbsoluteFilePath(real_to_path);
+    if (real_to_path.empty())
+      return false;
+  } else {
+    real_to_path = MakeAbsoluteFilePath(real_to_path.DirName());
+    if (real_to_path.empty())
+      return false;
+  }
+  FilePath real_from_path = MakeAbsoluteFilePath(from_path);
+  if (real_from_path.empty())
+    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)

[grt (UTC plus 2), 2014/01/24 20:50:07]

indent to align with 0 on previous line and add braces on account of
multi-line-ness

[M-A Ruel, 2014/01/24 21:32:57]

Done here and in file_util_posix.cc (where I copied the code from)

+    return false;
+
+  int traverse_type = FileEnumerator::FILES;
   if (recursive)
-    return ShellCopy(from_path, to_path, true);
+    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));
+  if (!PathExists(from_path)) {
+    DLOG(ERROR) << "CopyDirectory() couldn't stat source directory: "
+                << from_path.value().c_str();
+    return false;
+  }
+  // TODO(maruel): This is not necessary anymore.
+  DCHECK(recursive || DirectoryExists(from_path));
+
+  FilePath current = from_path;
+  bool from_is_dir = DirectoryExists(from_path);
+  bool success = true;
+  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();
+  }
 
-  // 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);
+  while (success && !current.empty()) {
+    // current is the source path, including from_path, so append
+    // the suffix after from_path to to_path to create the target_path.
+    FilePath target_path(to_path);
+    if (from_path_base != current) {
+      if (!from_path_base.AppendRelativePath(current, &target_path)) {
+        success = false;
+        break;
+      }
+    }
+
+    if (from_is_dir) {
+      if (!DirectoryExists(target_path) &&
+          !::CreateDirectory(target_path.value().c_str(), NULL)) {
+        DLOG(ERROR) << "CopyDirectory() couldn't create directory: "
+                    << target_path.value().c_str();
+        success = false;
+      }
+    } else if (!internal::CopyFileUnsafe(current, target_path)) {
+      DLOG(ERROR) << "CopyDirectory() couldn't create file: "
+                  << target_path.value().c_str();
+      success = false;
+    }
+
+    current = traversal.Next();
+    if (!current.empty())
+      from_is_dir = traversal.GetInfo().IsDirectory();
   }
 
-  FilePath directory = from_path.Append(L"*.*");
-  return ShellCopy(directory, to_path, false);
+  return success;
 }
 
 bool PathExists(const FilePath& path) {
@@ -720,6 +748,11 @@ bool MoveUnsafe(const FilePath& from_path, const FilePath& to_path) {
 }
 
 bool CopyFileUnsafe(const FilePath& from_path, const FilePath& to_path) {
+  // NOTE(maruel): Previous version of this function used to call CopyFile().
+  // This used to copy the file attributes and extended attributes, OLE
+  // structured storage, NTFS file system alternate data streams,
+  // SECURITY_DESCRIPTOR. In practice, this is not what we want, we want the
+  // containing directory to propagate its SECURITY_DESCRIPTOR.
   ThreadRestrictions::AssertIOAllowed();
 
   // NOTE: I suspect we could support longer paths, but that would involve
@@ -729,23 +762,49 @@ bool CopyFileUnsafe(const FilePath& from_path, const FilePath& to_path) {
     return false;
   }
 
-  // Unlike the posix implementation that copies the file manually and discards
-  // the ACL bits, CopyFile() copies the complete SECURITY_DESCRIPTOR and access
-  // bits, which is usually not what we want. We can't do much about the
-  // SECURITY_DESCRIPTOR but at least remove the read only bit.
-  const wchar_t* dest = to_path.value().c_str();
-  if (!::CopyFile(from_path.value().c_str(), dest, false)) {
-    // Copy failed.
+  base::win::ScopedHandle from_handle(
+      ::CreateFile(from_path.value().c_str(),
+                   GENERIC_READ,
+                   kFileShareAll,
+                   NULL,
+                   OPEN_EXISTING,
+                   FILE_FLAG_SEQUENTIAL_SCAN,
+                   NULL));
+  if (!from_handle)
     return false;
-  }
-  DWORD attrs = GetFileAttributes(dest);
-  if (attrs == INVALID_FILE_ATTRIBUTES) {
+  base::win::ScopedHandle to_handle(
+      ::CreateFile(to_path.value().c_str(),
+                   GENERIC_WRITE,
+                   kFileShareAll,

[grt (UTC plus 2), 2014/01/24 20:50:07]

kFileShareAll -> 0

[M-A Ruel, 2014/01/24 21:32:57]

Done.

+                   NULL,
+                   CREATE_ALWAYS,
+                   FILE_FLAG_SEQUENTIAL_SCAN,
+                   NULL));
+  if (!to_handle)
     return false;
+
+  std::vector<char> buffer(64*1024);

[M-A Ruel, 2014/01/24 19:52:31]

The posix version use 32kb but Windows really likes 64kb chunks.

[grt (UTC plus 2), 2014/01/24 20:50:07]

you don't seem to be using the power of vector (which, in addition to everything
else, zeroes out the buffer). how about:
  const DWORD kBufferSize = 64 * 1024;
  scoped_ptr<uint8_t[]> buffer(new uint8_t[kBufferSize]);

[M-A Ruel, 2014/01/24 21:32:57]

Done, but that still zero-out the memory. :)

[grt (UTC plus 2), 2014/01/26 23:55:08]

I don't think C++03 requires this. My read of the spec is that the contents of
memory returned by operator new[] are unspecified (3.7.3.1), and that for an
array of a scalar type like a char, the contents of the array has indeterminate
value (5.3.4 paragraph 15).

+  bool result = true;

[grt (UTC plus 2), 2014/01/24 20:50:07]

fewer lines of code if result starts as false and only becomes true when all
data has been copied.

[M-A Ruel, 2014/01/24 21:32:57]

Done.

+  while (result) {
+    DWORD size = 0;
+    if (!::ReadFile(from_handle, &buffer[0], buffer.size(), &size, NULL)) {
+      result = false;
+      break;
+    }
+    if (size == 0) {

[grt (UTC plus 2), 2014/01/24 20:50:07]

omit braces on single-line conditionals

[M-A Ruel, 2014/01/24 21:32:57]

Done.

+      break;
+    }
+    if (!::WriteFile(to_handle, &buffer[0], size, &size, NULL)) {
+      result = false;
+      break;
+    }
   }
-  if (attrs & FILE_ATTRIBUTE_READONLY) {
-    SetFileAttributes(dest, attrs & ~FILE_ATTRIBUTE_READONLY);
+  // If failed, try to delete the destination file.
+  if (!result) {
+    to_handle.Close();
+    DeleteFile(to_path, false);
   }
-  return true;
+  return result;
 }
 
 bool CopyAndDeleteDirectory(const FilePath& from_path,