base/files/file_enumerator_win.cc

   1 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "base/files/file_enumerator.h"
   6
   7 #include <string.h>
   8
   9 #include "base/logging.h"
  10 #include "base/threading/thread_restrictions.h"
  11 #include "base/win/windows_version.h"
  12
  13 namespace base {
  14
  15 // FileEnumerator::FileInfo ----------------------------------------------------
  16
  17 FileEnumerator::FileInfo::FileInfo() {
  18   memset(&find_data_, 0, sizeof(find_data_));
  19 }
  20
  21 bool FileEnumerator::FileInfo::IsDirectory() const {
  22   return (find_data_.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) != 0;
  23 }
  24
  25 FilePath FileEnumerator::FileInfo::GetName() const {
  26   return FilePath(find_data_.cFileName);
  27 }
  28
  29 int64 FileEnumerator::FileInfo::GetSize() const {
  30   ULARGE_INTEGER size;
  31   size.HighPart = find_data_.nFileSizeHigh;
  32   size.LowPart = find_data_.nFileSizeLow;
  33   DCHECK_LE(size.QuadPart,
  34             static_cast<ULONGLONG>(std::numeric_limits<int64>::max()));
  35   return static_cast<int64>(size.QuadPart);
  36 }
  37
  38 base::Time FileEnumerator::FileInfo::GetLastModifiedTime() const {
  39   return base::Time::FromFileTime(find_data_.ftLastWriteTime);
  40 }
  41
  42 // FileEnumerator --------------------------------------------------------------
  43
  44 FileEnumerator::FileEnumerator(const FilePath& root_path,
  45                                bool recursive,
  46                                int file_type)
  47     : has_find_data_(false),
  48       find_handle_(INVALID_HANDLE_VALUE),
  49       recursive_(recursive),
  50       file_type_(file_type) {
  51   // INCLUDE_DOT_DOT must not be specified if recursive.
  52   DCHECK(!(recursive && (INCLUDE_DOT_DOT & file_type_)));
  53   memset(&find_data_, 0, sizeof(find_data_));
  54   pending_paths_.push(root_path);
  55 }
  56
  57 FileEnumerator::FileEnumerator(const FilePath& root_path,
  58                                bool recursive,
  59                                int file_type,
  60                                const FilePath::StringType& pattern)
  61     : has_find_data_(false),
  62       find_handle_(INVALID_HANDLE_VALUE),
  63       recursive_(recursive),
  64       file_type_(file_type),
  65       pattern_(pattern) {
  66   // INCLUDE_DOT_DOT must not be specified if recursive.
  67   DCHECK(!(recursive && (INCLUDE_DOT_DOT & file_type_)));
  68   memset(&find_data_, 0, sizeof(find_data_));
  69   pending_paths_.push(root_path);
  70 }
  71
  72 FileEnumerator::~FileEnumerator() {
  73   if (find_handle_ != INVALID_HANDLE_VALUE)
  74     FindClose(find_handle_);
  75 }
  76
  77 FileEnumerator::FileInfo FileEnumerator::GetInfo() const {
  78   if (!has_find_data_) {
  79     NOTREACHED();
  80     return FileInfo();
  81   }
  82   FileInfo ret;
  83   memcpy(&ret.find_data_, &find_data_, sizeof(find_data_));
  84   return ret;
  85 }
  86
  87 FilePath FileEnumerator::Next() {
  88   base::ThreadRestrictions::AssertIOAllowed();
  89
  90   while (has_find_data_ || !pending_paths_.empty()) {
  91     if (!has_find_data_) {
  92       // The last find FindFirstFile operation is done, prepare a new one.
  93       root_path_ = pending_paths_.top();
  94       pending_paths_.pop();
  95
  96       // Start a new find operation.
  97       FilePath src = root_path_;
  98
  99       if (pattern_.empty())
 100         src = src.Append(L"*");  // No pattern = match everything.
 101       else
 102         src = src.Append(pattern_);
 103
 104       if (base::win::GetVersion() >= base::win::VERSION_WIN7) {
 105         // Use a "large fetch" on newer Windows which should speed up large
 106         // enumerations (we seldom abort in the middle).
 107         find_handle_ = FindFirstFileEx(src.value().c_str(),
 108                                        FindExInfoBasic,  // Omit short name.
 109                                        &find_data_,
 110                                        FindExSearchNameMatch,
 111                                        NULL,
 112                                        FIND_FIRST_EX_LARGE_FETCH);
 113       } else {
 114         find_handle_ = FindFirstFile(src.value().c_str(), &find_data_);
 115       }
 116       has_find_data_ = true;
 117     } else {
 118       // Search for the next file/directory.
 119       if (!FindNextFile(find_handle_, &find_data_)) {
 120         FindClose(find_handle_);
 121         find_handle_ = INVALID_HANDLE_VALUE;
 122       }
 123     }
 124
 125     if (INVALID_HANDLE_VALUE == find_handle_) {
 126       has_find_data_ = false;
 127
 128       // This is reached when we have finished a directory and are advancing to
 129       // the next one in the queue. We applied the pattern (if any) to the files
 130       // in the root search directory, but for those directories which were
 131       // matched, we want to enumerate all files inside them. This will happen
 132       // when the handle is empty.
 133       pattern_ = FilePath::StringType();
 134
 135       continue;
 136     }
 137
 138     FilePath cur_file(find_data_.cFileName);
 139     if (ShouldSkip(cur_file))
 140       continue;
 141
 142     // Construct the absolute filename.
 143     cur_file = root_path_.Append(find_data_.cFileName);
 144
 145     if (find_data_.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) {
 146       if (recursive_) {
 147         // If |cur_file| is a directory, and we are doing recursive searching,
 148         // add it to pending_paths_ so we scan it after we finish scanning this
 149         // directory. However, don't do recursion through reparse points or we
 150         // may end up with an infinite cycle.
 151         DWORD attributes = GetFileAttributes(cur_file.value().c_str());
 152         if (!(attributes & FILE_ATTRIBUTE_REPARSE_POINT))
 153           pending_paths_.push(cur_file);
 154       }
 155       if (file_type_ & FileEnumerator::DIRECTORIES)
 156         return cur_file;
 157     } else if (file_type_ & FileEnumerator::FILES) {
 158       return cur_file;
 159     }
 160   }
 161
 162   return FilePath();
 163 }
 164
 165 }  // namespace base