webkit/browser/fileapi/file_system_url.h

   1 // Copyright (c) 2012 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 #ifndef WEBKIT_BROWSER_FILEAPI_FILE_SYSTEM_URL_H_
   6 #define WEBKIT_BROWSER_FILEAPI_FILE_SYSTEM_URL_H_
   7
   8 #include <set>
   9 #include <string>
  10
  11 #include "base/platform_file.h"
  12 #include "url/gurl.h"
  13 #include "webkit/browser/webkit_storage_browser_export.h"
  14 #include "webkit/common/fileapi/file_system_types.h"
  15
  16 namespace fileapi {
  17
  18 // A class representing a filesystem URL which consists of origin URL,
  19 // type and an internal path used inside the filesystem.
  20 //
  21 // When a FileSystemURL instance is created for a GURL (for filesystem: scheme),
  22 // each accessor method would return following values:
  23 //
  24 // Example: For a URL 'filesystem:http://foo.com/temporary/foo/bar':
  25 //   origin() returns 'http://foo.com',
  26 //   mount_type() returns kFileSystemTypeTemporary,
  27 //   virtual_path() returns 'foo/bar',
  28 //   type() returns the same value as mount_type(),
  29 //   path() returns the same value as virtual_path(),
  30 //
  31 // All other accessors return empty or invalid value.
  32 //
  33 // FileSystemURL can also be created to represent a 'cracked' filesystem URL if
  34 // the original URL's type/path is pointing to a mount point which can be
  35 // further resolved to a lower filesystem type/path.
  36 //
  37 // Example: Assume a path '/media/removable' is mounted at mount name
  38 // 'mount_name' with type kFileSystemTypeFoo as an external file system.
  39 //
  40 // The original URL would look like:
  41 //     'filesystem:http://bar.com/external/mount_name/foo/bar':
  42 //
  43 // FileSystemURL('http://bar.com',
  44 //               kFileSystemTypeExternal,
  45 //               'mount_name/foo/bar'
  46 //               'mount_name',
  47 //               kFileSystemTypeFoo,
  48 //               '/media/removable/foo/bar');
  49 // would create a FileSystemURL whose accessors return:
  50 //
  51 //   origin() returns 'http://bar.com',
  52 //   mount_type() returns kFileSystemTypeExternal,
  53 //   virtual_path() returns 'mount_name/foo/bar',
  54 //   type() returns the kFileSystemTypeFoo,
  55 //   path() returns '/media/removable/foo/bar',
  56 //
  57 // Note that in either case virtual_path() always returns the path part after
  58 // 'type' part in the original URL, and mount_type() always returns the 'type'
  59 // part in the original URL.
  60 //
  61 // Additionally, following accessors would return valid values:
  62 //   filesystem_id() returns 'mount_name'.
  63 //
  64 // It is impossible to directly create a valid FileSystemURL instance (except by
  65 // using CreatedForTest methods, which should not be used in production code).
  66 // To get a valid FileSystemURL, one of the following methods can be used:
  67 // <Friend>::CrackURL, <Friend>::CreateCrackedFileSystemURL, where <Friend> is
  68 // one of the friended classes.
  69 //
  70 // TODO(ericu): Look into making virtual_path() [and all FileSystem API virtual
  71 // paths] just an std::string, to prevent platform-specific base::FilePath
  72 // behavior from getting invoked by accident. Currently the base::FilePath
  73 // returned here needs special treatment, as it may contain paths that are
  74 // illegal on the current platform.
  75 // To avoid problems, use VirtualPath::BaseName and
  76 // VirtualPath::GetComponents instead of the base::FilePath methods.
  77 class WEBKIT_STORAGE_BROWSER_EXPORT FileSystemURL {
  78  public:
  79   FileSystemURL();
  80   ~FileSystemURL();
  81
  82   // Methods for creating FileSystemURL without attempting to crack them.
  83   // Should be used only in tests.
  84   static FileSystemURL CreateForTest(const GURL& url);
  85   static FileSystemURL CreateForTest(const GURL& origin,
  86                                      FileSystemType mount_type,
  87                                      const base::FilePath& virtual_path);
  88
  89   // Parses filesystem scheme |url| into uncracked FileSystemURL components.
  90   static bool ParseFileSystemSchemeURL(const GURL& url,
  91                                        GURL* origin,
  92                                        FileSystemType* mount_type,
  93                                        base::FilePath* virtual_path);
  94
  95   // Returns true if this instance represents a valid FileSystem URL.
  96   bool is_valid() const { return is_valid_; }
  97
  98   // Returns the origin part of this URL. See the class comment for details.
  99   const GURL& origin() const { return origin_; }
 100
 101   // Returns the type part of this URL. See the class comment for details.
 102   FileSystemType type() const { return type_; }
 103
 104   // Returns the cracked path of this URL. See the class comment for details.
 105   const base::FilePath& path() const { return path_; }
 106
 107   // Returns the original path part of this URL.
 108   // See the class comment for details.
 109   // TODO(kinuko): this must return std::string.
 110   const base::FilePath& virtual_path() const { return virtual_path_; }
 111
 112   // Returns the filesystem ID/mount name for isolated/external filesystem URLs.
 113   // See the class comment for details.
 114   const std::string& filesystem_id() const { return filesystem_id_; }
 115   const std::string& mount_filesystem_id() const {
 116     return mount_filesystem_id_;
 117   }
 118
 119   FileSystemType mount_type() const { return mount_type_; }
 120
 121   // Returns the formatted URL of this instance.
 122   GURL ToGURL() const;
 123
 124   std::string DebugString() const;
 125
 126   // Returns true if this URL is a strict parent of the |child|.
 127   bool IsParent(const FileSystemURL& child) const;
 128
 129   bool IsInSameFileSystem(const FileSystemURL& other) const;
 130
 131   bool operator==(const FileSystemURL& that) const;
 132
 133   bool operator!=(const FileSystemURL& that) const {
 134     return !(*this == that);
 135   }
 136
 137   struct WEBKIT_STORAGE_BROWSER_EXPORT Comparator {
 138     bool operator() (const FileSystemURL& lhs, const FileSystemURL& rhs) const;
 139   };
 140
 141  private:
 142   friend class FileSystemContext;
 143   friend class ExternalMountPoints;
 144   friend class IsolatedContext;
 145
 146   explicit FileSystemURL(const GURL& filesystem_url);
 147   FileSystemURL(const GURL& origin,
 148                 FileSystemType mount_type,
 149                 const base::FilePath& virtual_path);
 150   // Creates a cracked FileSystemURL.
 151   FileSystemURL(const GURL& origin,
 152                 FileSystemType mount_type,
 153                 const base::FilePath& virtual_path,
 154                 const std::string& mount_filesystem_id,
 155                 FileSystemType cracked_type,
 156                 const base::FilePath& cracked_path,
 157                 const std::string& filesystem_id);
 158
 159   bool is_valid_;
 160
 161   // Values parsed from the original URL.
 162   GURL origin_;
 163   FileSystemType mount_type_;
 164   base::FilePath virtual_path_;
 165
 166   // Values obtained by cracking URLs.
 167   // |mount_filesystem_id_| is retrieved from the first round of cracking,
 168   // and the rest of the fields are from recursive cracking. Permission
 169   // checking on the top-level mount information should be done with the former,
 170   // and the low-level file operation should be implemented with the latter.
 171   std::string mount_filesystem_id_;
 172   FileSystemType type_;
 173   base::FilePath path_;
 174   std::string filesystem_id_;
 175 };
 176
 177 typedef std::set<FileSystemURL, FileSystemURL::Comparator> FileSystemURLSet;
 178
 179 }  // namespace fileapi
 180
 181 #endif  // WEBKIT_BROWSER_FILEAPI_FILE_SYSTEM_URL_H_