ppapi/cpp/directory_entry.h

   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 #ifndef PPAPI_CPP_DIRECTORY_ENTRY_H_
   6 #define PPAPI_CPP_DIRECTORY_ENTRY_H_
   7
   8 #include <vector>
   9
  10 #include "ppapi/c/pp_array_output.h"
  11 #include "ppapi/c/pp_directory_entry.h"
  12 #include "ppapi/cpp/array_output.h"
  13 #include "ppapi/cpp/file_ref.h"
  14 #include "ppapi/cpp/output_traits.h"
  15 #include "ppapi/cpp/pass_ref.h"
  16
  17 /// @file
  18 /// This file defines the API used to handle a directory entry.
  19
  20 namespace pp {
  21
  22 /// The <code>DirectoryEntry</code> class represents information about
  23 /// a directory entry.
  24 class DirectoryEntry {
  25  public:
  26   /// Default constructor for creating an is_null() <code>DirectoryEntry</code>
  27   /// object.
  28   DirectoryEntry();
  29
  30   /// A constructor used when you have a <code>PP_DirectoryEntry</code> which
  31   /// contains a <code>FileRef</code> that has already been reference counted
  32   /// as a return value.
  33   ///
  34   /// @param[in] data A <code>PP_DirectoryEntry</code> to be copied.
  35   DirectoryEntry(PassRef, const PP_DirectoryEntry& data);
  36
  37   /// A copy constructor for <code>DirectoryEntry</code>. This constructor
  38   /// increments a reference count of the <code>FileRef</code> held by this
  39   /// DirectoryEntry.
  40   ///
  41   /// @param[in] other A pointer to a <code>DirectoryEntry</code>.
  42   DirectoryEntry(const DirectoryEntry& other);
  43
  44   /// A destructor that decrements a reference count of the <code>FileRef</code>
  45   /// held by this <code>DirectoryEntry</code>.
  46   ~DirectoryEntry();
  47
  48   /// This function assigns one <code>DirectoryEntry</code> object to this
  49   /// <code>DirectoryEntry</code> object. This function increases the reference
  50   /// count of the <code>FileRef</code> of the other DirectoryEntry while
  51   /// decrementing the reference count of the FileRef of this DirectoryEntry.
  52   ///
  53   /// @param[in] other A pointer to a <code>DirectoryEntry</code>.
  54   ///
  55   /// @return A new <code>DirectoryEntry</code> object.
  56   DirectoryEntry& operator=(const DirectoryEntry& other);
  57
  58   /// This function determines if this <code>DirectoryEntry</code> is a null
  59   /// value.
  60   ///
  61   /// @return true if this <code>DirectoryEntry</code> is null, otherwise false.
  62   bool is_null() const { return !data_.file_ref; }
  63
  64   /// This function returns the <code>FileRef</code> held by this
  65   /// <code>DirectoryEntry</code>.
  66   ///
  67   /// @return A <code>FileRef</code> of the file.
  68   FileRef file_ref() const { return FileRef(data_.file_ref); }
  69
  70   /// This function returns the <code>PP_FileType</code> of the file referenced
  71   /// by this <code>DirectoryEntry</code>.
  72   ///
  73   /// @return A <code>PP_FileType</code> of the file.
  74   PP_FileType file_type() const { return data_.file_type; }
  75
  76  private:
  77   PP_DirectoryEntry data_;
  78 };
  79
  80 namespace internal {
  81
  82 class DirectoryEntryArrayOutputAdapterWithStorage
  83     : public ArrayOutputAdapter<PP_DirectoryEntry> {
  84  public:
  85   DirectoryEntryArrayOutputAdapterWithStorage();
  86   virtual ~DirectoryEntryArrayOutputAdapterWithStorage();
  87
  88   // Returns the final array of resource objects, converting the
  89   // PP_DirectoryEntry written by the browser to pp::DirectoryEntry
  90   // objects.
  91   //
  92   // This function should only be called once or we would end up converting
  93   // the array more than once, which would mess up the refcounting.
  94   std::vector<DirectoryEntry>& output();
  95
  96  private:
  97   // The browser will write the PP_DirectoryEntrys into this array.
  98   std::vector<PP_DirectoryEntry> temp_storage_;
  99
 100   // When asked for the output, the PP_DirectoryEntrys above will be
 101   // converted to the pp::DirectoryEntrys in this array for passing to the
 102   // calling code.
 103   std::vector<DirectoryEntry> output_storage_;
 104 };
 105
 106 // A specialization of CallbackOutputTraits to provide the callback system the
 107 // information on how to handle vectors of pp::DirectoryEntry. This converts
 108 // PP_DirectoryEntry to pp::DirectoryEntry when passing to the plugin.
 109 template <>
 110 struct CallbackOutputTraits< std::vector<DirectoryEntry> > {
 111   typedef PP_ArrayOutput APIArgType;
 112   typedef DirectoryEntryArrayOutputAdapterWithStorage StorageType;
 113
 114   static inline APIArgType StorageToAPIArg(StorageType& t) {
 115     return t.pp_array_output();
 116   }
 117
 118   static inline std::vector<DirectoryEntry>& StorageToPluginArg(
 119       StorageType& t) {
 120     return t.output();
 121   }
 122
 123   static inline void Initialize(StorageType* /* t */) {}
 124 };
 125
 126 }  // namespace internal
 127 }  // namespace pp
 128
 129 #endif  // PPAPI_CPP_DIRECTORY_ENTRY_H_