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      1 /*
      2  * Copyright (C) 2010 Google Inc. All rights reserved.
      3  *
      4  * Redistribution and use in source and binary forms, with or without
      5  * modification, are permitted provided that the following conditions are
      6  * met:
      7  *
      8  *     * Redistributions of source code must retain the above copyright
      9  * notice, this list of conditions and the following disclaimer.
     10  *     * Redistributions in binary form must reproduce the above
     11  * copyright notice, this list of conditions and the following disclaimer
     12  * in the documentation and/or other materials provided with the
     13  * distribution.
     14  *     * Neither the name of Google Inc. nor the names of its
     15  * contributors may be used to endorse or promote products derived from
     16  * this software without specific prior written permission.
     17  *
     18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     19  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     20  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     21  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     22  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     23  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     24  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     28  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     29  */
     30 
     31 #include "config.h"
     32 #include "modules/filesystem/DOMFilePath.h"
     33 
     34 #include "wtf/Vector.h"
     35 #include "wtf/text/CString.h"
     36 
     37 namespace WebCore {
     38 
     39 const char DOMFilePath::separator = '/';
     40 const char DOMFilePath::root[] = "/";
     41 
     42 String DOMFilePath::append(const String& base, const String& components)
     43 {
     44     return ensureDirectoryPath(base) + components;
     45 }
     46 
     47 String DOMFilePath::ensureDirectoryPath(const String& path)
     48 {
     49     if (!DOMFilePath::endsWithSeparator(path)) {
     50         String newPath = path;
     51         newPath.append(DOMFilePath::separator);
     52         return newPath;
     53     }
     54     return path;
     55 }
     56 
     57 String DOMFilePath::getName(const String& path)
     58 {
     59     int index = path.reverseFind(DOMFilePath::separator);
     60     if (index != -1)
     61         return path.substring(index + 1);
     62     return path;
     63 }
     64 
     65 String DOMFilePath::getDirectory(const String& path)
     66 {
     67     int index = path.reverseFind(DOMFilePath::separator);
     68     if (!index)
     69         return DOMFilePath::root;
     70     if (index != -1)
     71         return path.substring(0, index);
     72     return ".";
     73 }
     74 
     75 bool DOMFilePath::isParentOf(const String& parent, const String& mayBeChild)
     76 {
     77     ASSERT(DOMFilePath::isAbsolute(parent));
     78     ASSERT(DOMFilePath::isAbsolute(mayBeChild));
     79     if (parent == DOMFilePath::root && mayBeChild != DOMFilePath::root)
     80         return true;
     81     if (parent.length() >= mayBeChild.length() || !mayBeChild.startsWith(parent, false))
     82         return false;
     83     if (mayBeChild[parent.length()] != DOMFilePath::separator)
     84         return false;
     85     return true;
     86 }
     87 
     88 String DOMFilePath::removeExtraParentReferences(const String& path)
     89 {
     90     ASSERT(DOMFilePath::isAbsolute(path));
     91     Vector<String> components;
     92     Vector<String> canonicalized;
     93     path.split(DOMFilePath::separator, components);
     94     for (size_t i = 0; i < components.size(); ++i) {
     95         if (components[i] == ".")
     96             continue;
     97         if (components[i] == "..") {
     98             if (canonicalized.size() > 0)
     99                 canonicalized.removeLast();
    100             continue;
    101         }
    102         canonicalized.append(components[i]);
    103     }
    104     if (canonicalized.isEmpty())
    105         return DOMFilePath::root;
    106     String result;
    107     for (size_t i = 0; i < canonicalized.size(); ++i) {
    108         result.append(DOMFilePath::separator);
    109         result.append(canonicalized[i]);
    110     }
    111     return result;
    112 }
    113 
    114 bool DOMFilePath::isValidPath(const String& path)
    115 {
    116     if (path.isEmpty() || path == DOMFilePath::root)
    117         return true;
    118 
    119     // Embedded NULs are not allowed.
    120     if (path.find(static_cast<UChar>(0)) != WTF::kNotFound)
    121         return false;
    122 
    123     // While not [yet] restricted by the spec, '\\' complicates implementation for Chromium.
    124     if (path.find('\\') != WTF::kNotFound)
    125         return false;
    126 
    127     // This method is only called on fully-evaluated absolute paths. Any sign of ".." or "." is likely an attempt to break out of the sandbox.
    128     Vector<String> components;
    129     path.split(DOMFilePath::separator, components);
    130     for (size_t i = 0; i < components.size(); ++i) {
    131         if (components[i] == ".")
    132             return false;
    133         if (components[i] == "..")
    134             return false;
    135     }
    136     return true;
    137 }
    138 
    139 bool DOMFilePath::isValidName(const String& name)
    140 {
    141     if (name.isEmpty())
    142         return true;
    143     // '/' is not allowed in name.
    144     if (name.contains('/'))
    145         return false;
    146     return isValidPath(name);
    147 }
    148 
    149 } // namespace WebCore
    150