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      1 // Copyright (c) 2011 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 // File utilities that use the ICU library go in this file.
      6 
      7 #include "base/i18n/file_util_icu.h"
      8 
      9 #include "base/file_path.h"
     10 #include "base/logging.h"
     11 #include "base/memory/scoped_ptr.h"
     12 #include "base/memory/singleton.h"
     13 #include "base/string_util.h"
     14 #include "base/utf_string_conversions.h"
     15 #include "base/sys_string_conversions.h"
     16 #include "build/build_config.h"
     17 #include "unicode/coll.h"
     18 #include "unicode/uniset.h"
     19 
     20 namespace {
     21 
     22 class IllegalCharacters {
     23  public:
     24   static IllegalCharacters* GetInstance() {
     25     return Singleton<IllegalCharacters>::get();
     26   }
     27 
     28   bool contains(UChar32 ucs4) {
     29     return !!set->contains(ucs4);
     30   }
     31 
     32   bool containsNone(const string16 &s) {
     33     return !!set->containsNone(icu::UnicodeString(s.c_str(), s.size()));
     34   }
     35 
     36  private:
     37   friend class Singleton<IllegalCharacters>;
     38   friend struct DefaultSingletonTraits<IllegalCharacters>;
     39 
     40   IllegalCharacters();
     41   ~IllegalCharacters() { }
     42 
     43   scoped_ptr<icu::UnicodeSet> set;
     44 
     45   DISALLOW_COPY_AND_ASSIGN(IllegalCharacters);
     46 };
     47 
     48 IllegalCharacters::IllegalCharacters() {
     49   UErrorCode status = U_ZERO_ERROR;
     50   // Control characters, formatting characters, non-characters, and
     51   // some printable ASCII characters regarded as dangerous ('"*/:<>?\\').
     52   // See  http://blogs.msdn.com/michkap/archive/2006/11/03/941420.aspx
     53   // and http://msdn2.microsoft.com/en-us/library/Aa365247.aspx
     54   // TODO(jungshik): Revisit the set. ZWJ and ZWNJ are excluded because they
     55   // are legitimate in Arabic and some S/SE Asian scripts. However, when used
     56   // elsewhere, they can be confusing/problematic.
     57   // Also, consider wrapping the set with our Singleton class to create and
     58   // freeze it only once. Note that there's a trade-off between memory and
     59   // speed.
     60 #if defined(WCHAR_T_IS_UTF16)
     61   set.reset(new icu::UnicodeSet(icu::UnicodeString(
     62       L"[[\"*/:<>?\\\\|][:Cc:][:Cf:] - [\u200c\u200d]]"), status));
     63 #else
     64   set.reset(new icu::UnicodeSet(UNICODE_STRING_SIMPLE(
     65       "[[\"*/:<>?\\\\|][:Cc:][:Cf:] - [\\u200c\\u200d]]").unescape(),
     66       status));
     67 #endif
     68   DCHECK(U_SUCCESS(status));
     69   // Add non-characters. If this becomes a performance bottleneck by
     70   // any chance, do not add these to |set| and change IsFilenameLegal()
     71   // to check |ucs4 & 0xFFFEu == 0xFFFEu|, in addiition to calling
     72   // containsNone().
     73   set->add(0xFDD0, 0xFDEF);
     74   for (int i = 0; i <= 0x10; ++i) {
     75     int plane_base = 0x10000 * i;
     76     set->add(plane_base + 0xFFFE, plane_base + 0xFFFF);
     77   }
     78   set->freeze();
     79 }
     80 
     81 class LocaleAwareComparator {
     82  public:
     83   static LocaleAwareComparator* GetInstance() {
     84     return Singleton<LocaleAwareComparator>::get();
     85   }
     86 
     87   // Note: A similar function is available in l10n_util.
     88   // We cannot use it because base should not depend on l10n_util.
     89   // TODO(yuzo): Move some of l10n_util to base.
     90   int Compare(const string16& a, const string16& b) {
     91     // We are not sure if Collator::compare is thread-safe.
     92     // Use an AutoLock just in case.
     93     base::AutoLock auto_lock(lock_);
     94 
     95     UErrorCode error_code = U_ZERO_ERROR;
     96     UCollationResult result = collator_->compare(
     97         static_cast<const UChar*>(a.c_str()),
     98         static_cast<int>(a.length()),
     99         static_cast<const UChar*>(b.c_str()),
    100         static_cast<int>(b.length()),
    101         error_code);
    102     DCHECK(U_SUCCESS(error_code));
    103     return result;
    104   }
    105 
    106  private:
    107   LocaleAwareComparator() {
    108     UErrorCode error_code = U_ZERO_ERROR;
    109     // Use the default collator. The default locale should have been properly
    110     // set by the time this constructor is called.
    111     collator_.reset(icu::Collator::createInstance(error_code));
    112     DCHECK(U_SUCCESS(error_code));
    113     // Make it case-sensitive.
    114     collator_->setStrength(icu::Collator::TERTIARY);
    115     // Note: We do not set UCOL_NORMALIZATION_MODE attribute. In other words, we
    116     // do not pay performance penalty to guarantee sort order correctness for
    117     // non-FCD (http://unicode.org/notes/tn5/#FCD) file names. This should be a
    118     // reasonable tradeoff because such file names should be rare and the sort
    119     // order doesn't change much anyway.
    120   }
    121 
    122   scoped_ptr<icu::Collator> collator_;
    123   base::Lock lock_;
    124   friend struct DefaultSingletonTraits<LocaleAwareComparator>;
    125 
    126   DISALLOW_COPY_AND_ASSIGN(LocaleAwareComparator);
    127 };
    128 
    129 }  // namespace
    130 
    131 namespace file_util {
    132 
    133 bool IsFilenameLegal(const string16& file_name) {
    134   return IllegalCharacters::GetInstance()->containsNone(file_name);
    135 }
    136 
    137 void ReplaceIllegalCharactersInPath(FilePath::StringType* file_name,
    138                                     char replace_char) {
    139   DCHECK(file_name);
    140 
    141   DCHECK(!(IllegalCharacters::GetInstance()->contains(replace_char)));
    142 
    143   // Remove leading and trailing whitespace.
    144   TrimWhitespace(*file_name, TRIM_ALL, file_name);
    145 
    146   IllegalCharacters* illegal = IllegalCharacters::GetInstance();
    147   int cursor = 0;  // The ICU macros expect an int.
    148   while (cursor < static_cast<int>(file_name->size())) {
    149     int char_begin = cursor;
    150     uint32 code_point;
    151 #if defined(OS_MACOSX)
    152     // Mac uses UTF-8 encoding for filenames.
    153     U8_NEXT(file_name->data(), cursor, static_cast<int>(file_name->length()),
    154             code_point);
    155 #elif defined(OS_WIN)
    156     // Windows uses UTF-16 encoding for filenames.
    157     U16_NEXT(file_name->data(), cursor, static_cast<int>(file_name->length()),
    158              code_point);
    159 #elif defined(OS_POSIX)
    160     // Linux doesn't actually define an encoding. It basically allows anything
    161     // except for a few special ASCII characters.
    162     unsigned char cur_char = static_cast<unsigned char>((*file_name)[cursor++]);
    163     if (cur_char >= 0x80)
    164       continue;
    165     code_point = cur_char;
    166 #else
    167     NOTREACHED();
    168 #endif
    169 
    170     if (illegal->contains(code_point)) {
    171       file_name->replace(char_begin, cursor - char_begin, 1, replace_char);
    172       // We just made the potentially multi-byte/word char into one that only
    173       // takes one byte/word, so need to adjust the cursor to point to the next
    174       // character again.
    175       cursor = char_begin + 1;
    176     }
    177   }
    178 }
    179 
    180 bool LocaleAwareCompareFilenames(const FilePath& a, const FilePath& b) {
    181 #if defined(OS_WIN)
    182   return LocaleAwareComparator::GetInstance()->Compare(a.value().c_str(),
    183                                                        b.value().c_str()) < 0;
    184 
    185 #elif defined(OS_POSIX)
    186   // On linux, the file system encoding is not defined. We assume
    187   // SysNativeMBToWide takes care of it.
    188   //
    189   // ICU's collator can take strings in OS native encoding. But we convert the
    190   // strings to UTF-16 ourselves to ensure conversion consistency.
    191   // TODO(yuzo): Perhaps we should define SysNativeMBToUTF16?
    192   return LocaleAwareComparator::GetInstance()->Compare(
    193       WideToUTF16(base::SysNativeMBToWide(a.value().c_str())),
    194       WideToUTF16(base::SysNativeMBToWide(b.value().c_str()))) < 0;
    195 #else
    196   #error Not implemented on your system
    197 #endif
    198 }
    199 
    200 }  // namespace
    201