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