ppapi/proxy/file_io_resource.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 PPAPI_PROXY_FILE_IO_RESOURCE_H_
   6 #define PPAPI_PROXY_FILE_IO_RESOURCE_H_
   7
   8 #include <string>
   9
  10 #include "base/files/file.h"
  11 #include "base/memory/ref_counted.h"
  12 #include "base/memory/scoped_ptr.h"
  13 #include "ppapi/c/private/pp_file_handle.h"
  14 #include "ppapi/proxy/connection.h"
  15 #include "ppapi/proxy/plugin_resource.h"
  16 #include "ppapi/proxy/ppapi_proxy_export.h"
  17 #include "ppapi/shared_impl/file_io_state_manager.h"
  18 #include "ppapi/shared_impl/resource.h"
  19 #include "ppapi/shared_impl/scoped_pp_resource.h"
  20 #include "ppapi/thunk/ppb_file_io_api.h"
  21
  22 namespace ppapi {
  23
  24 class TrackedCallback;
  25
  26 namespace proxy {
  27
  28 class PPAPI_PROXY_EXPORT FileIOResource
  29     : public PluginResource,
  30       public thunk::PPB_FileIO_API {
  31  public:
  32   FileIOResource(Connection connection, PP_Instance instance);
  33   virtual ~FileIOResource();
  34
  35   // Resource overrides.
  36   virtual thunk::PPB_FileIO_API* AsPPB_FileIO_API() OVERRIDE;
  37
  38   // PPB_FileIO_API implementation.
  39   virtual int32_t Open(PP_Resource file_ref,
  40                        int32_t open_flags,
  41                        scoped_refptr<TrackedCallback> callback) OVERRIDE;
  42   virtual int32_t Query(PP_FileInfo* info,
  43                         scoped_refptr<TrackedCallback> callback) OVERRIDE;
  44   virtual int32_t Touch(PP_Time last_access_time,
  45                         PP_Time last_modified_time,
  46                         scoped_refptr<TrackedCallback> callback) OVERRIDE;
  47   virtual int32_t Read(int64_t offset,
  48                        char* buffer,
  49                        int32_t bytes_to_read,
  50                        scoped_refptr<TrackedCallback> callback) OVERRIDE;
  51   virtual int32_t ReadToArray(int64_t offset,
  52                               int32_t max_read_length,
  53                               PP_ArrayOutput* array_output,
  54                               scoped_refptr<TrackedCallback> callback) OVERRIDE;
  55   virtual int32_t Write(int64_t offset,
  56                         const char* buffer,
  57                         int32_t bytes_to_write,
  58                         scoped_refptr<TrackedCallback> callback) OVERRIDE;
  59   virtual int32_t SetLength(int64_t length,
  60                             scoped_refptr<TrackedCallback> callback) OVERRIDE;
  61   virtual int64_t GetMaxWrittenOffset() const OVERRIDE;
  62   virtual int64_t GetAppendModeWriteAmount() const OVERRIDE;
  63   virtual void SetMaxWrittenOffset(int64_t max_written_offset) OVERRIDE;
  64   virtual void SetAppendModeWriteAmount(
  65       int64_t append_mode_write_amount) OVERRIDE;
  66   virtual int32_t Flush(scoped_refptr<TrackedCallback> callback) OVERRIDE;
  67   virtual void Close() OVERRIDE;
  68   virtual int32_t RequestOSFileHandle(
  69       PP_FileHandle* handle,
  70       scoped_refptr<TrackedCallback> callback) OVERRIDE;
  71
  72   // FileHolder is used to guarantee that file operations will have a valid FD
  73   // to operate on, even if they're in a different thread.
  74   // If instead we just passed the raw FD, the FD could be closed before the
  75   // file operation has a chance to run. It could interact with an invalid FD,
  76   // or worse, the FD value could be reused if another file is opened quickly
  77   // (POSIX is required to provide the lowest available value when opening a
  78   // file). This could result in strange problems such as writing data to the
  79   // wrong file.
  80   //
  81   // Operations that run on a background thread should hold one of these to
  82   // ensure they have a valid file descriptor. The file handle is only closed
  83   // when the last reference to the FileHolder is removed, so we are guaranteed
  84   // to operate on the correct file descriptor. It *is* still possible that the
  85   // FileIOResource will be destroyed and "Abort" callbacks just before the
  86   // operation does its task (e.g., Reading). In that case, we might for example
  87   // Read from a file even though the FileIO has been destroyed and the plugin's
  88   // callback got a PP_ERROR_ABORTED result. In the case of a write, we could
  89   // write some data to the file despite the plugin receiving a
  90   // PP_ERROR_ABORTED instead of a successful result.
  91   class FileHolder : public base::RefCountedThreadSafe<FileHolder> {
  92    public:
  93     explicit FileHolder(PP_FileHandle file_handle);
  94     base::File* file() {
  95       return &file_;
  96     }
  97     static bool IsValid(
  98         const scoped_refptr<FileIOResource::FileHolder>& handle);
  99    private:
 100     friend class base::RefCountedThreadSafe<FileHolder>;
 101     ~FileHolder();
 102     base::File file_;
 103   };
 104
 105   scoped_refptr<FileHolder> file_holder() {
 106     return file_holder_;
 107   }
 108
 109  private:
 110   // Class to perform file query operations across multiple threads.
 111   class QueryOp : public base::RefCountedThreadSafe<QueryOp> {
 112    public:
 113     explicit QueryOp(scoped_refptr<FileHolder> file_holder);
 114
 115     // Queries the file. Called on the file thread (non-blocking) or the plugin
 116     // thread (blocking). This should not be called when we hold the proxy lock.
 117     int32_t DoWork();
 118
 119     const base::File::Info& file_info() const { return file_info_; }
 120
 121    private:
 122     friend class base::RefCountedThreadSafe<QueryOp>;
 123     ~QueryOp();
 124
 125     scoped_refptr<FileHolder> file_holder_;
 126     base::File::Info file_info_;
 127   };
 128
 129   // Class to perform file read operations across multiple threads.
 130   class ReadOp : public base::RefCountedThreadSafe<ReadOp> {
 131    public:
 132     ReadOp(scoped_refptr<FileHolder> file_holder,
 133            int64_t offset,
 134            int32_t bytes_to_read);
 135
 136     // Reads the file. Called on the file thread (non-blocking) or the plugin
 137     // thread (blocking). This should not be called when we hold the proxy lock.
 138     int32_t DoWork();
 139
 140     char* buffer() const { return buffer_.get(); }
 141
 142    private:
 143     friend class base::RefCountedThreadSafe<ReadOp>;
 144     ~ReadOp();
 145
 146     scoped_refptr<FileHolder> file_holder_;
 147     int64_t offset_;
 148     int32_t bytes_to_read_;
 149     scoped_ptr<char[]> buffer_;
 150   };
 151
 152   // Class to perform file write operations across multiple threads.
 153   class WriteOp : public base::RefCountedThreadSafe<WriteOp> {
 154    public:
 155     WriteOp(scoped_refptr<FileHolder> file_holder,
 156             int64_t offset,
 157             scoped_ptr<char[]> buffer,
 158             int32_t bytes_to_write,
 159             bool append);
 160
 161     // Writes the file. Called on the file thread (non-blocking) or the plugin
 162     // thread (blocking). This should not be called when we hold the proxy lock.
 163     int32_t DoWork();
 164
 165    private:
 166     friend class base::RefCountedThreadSafe<WriteOp>;
 167     ~WriteOp();
 168
 169     scoped_refptr<FileHolder> file_holder_;
 170     int64_t offset_;
 171     scoped_ptr<char[]> buffer_;
 172     int32_t bytes_to_write_;
 173     bool append_;
 174   };
 175
 176   void OnRequestWriteQuotaComplete(int64_t offset,
 177                                    scoped_ptr<char[]> buffer,
 178                                    int32_t bytes_to_write,
 179                                    scoped_refptr<TrackedCallback> callback,
 180                                    int64_t granted);
 181   void OnRequestSetLengthQuotaComplete(int64_t length,
 182                                        scoped_refptr<TrackedCallback> callback,
 183                                        int64_t granted);
 184
 185   int32_t ReadValidated(int64_t offset,
 186                         int32_t bytes_to_read,
 187                         const PP_ArrayOutput& array_output,
 188                         scoped_refptr<TrackedCallback> callback);
 189   int32_t WriteValidated(int64_t offset,
 190                          const char* buffer,
 191                          int32_t bytes_to_write,
 192                          scoped_refptr<TrackedCallback> callback);
 193   void SetLengthValidated(int64_t length,
 194                           scoped_refptr<TrackedCallback> callback);
 195
 196   // Completion tasks for file operations that are done in the plugin.
 197   int32_t OnQueryComplete(scoped_refptr<QueryOp> query_op,
 198                           PP_FileInfo* info,
 199                           int32_t result);
 200   int32_t OnReadComplete(scoped_refptr<ReadOp> read_op,
 201                          PP_ArrayOutput array_output,
 202                          int32_t result);
 203   int32_t OnWriteComplete(int32_t result);
 204
 205   // Reply message handlers for operations that are done in the host.
 206   void OnPluginMsgGeneralComplete(scoped_refptr<TrackedCallback> callback,
 207                                   const ResourceMessageReplyParams& params);
 208   void OnPluginMsgOpenFileComplete(scoped_refptr<TrackedCallback> callback,
 209                                    const ResourceMessageReplyParams& params,
 210                                    PP_Resource quota_file_system,
 211                                    int64_t max_written_offset);
 212   void OnPluginMsgRequestOSFileHandleComplete(
 213       scoped_refptr<TrackedCallback> callback,
 214       PP_FileHandle* output_handle,
 215       const ResourceMessageReplyParams& params);
 216
 217   scoped_refptr<FileHolder> file_holder_;
 218   PP_FileSystemType file_system_type_;
 219   scoped_refptr<Resource> file_system_resource_;
 220   FileIOStateManager state_manager_;
 221
 222   scoped_refptr<Resource> file_ref_;
 223
 224   int32_t open_flags_;
 225   int64_t max_written_offset_;
 226   int64_t append_mode_write_amount_;
 227   bool check_quota_;
 228   bool called_close_;
 229
 230   DISALLOW_COPY_AND_ASSIGN(FileIOResource);
 231 };
 232
 233 }  // namespace proxy
 234 }  // namespace ppapi
 235
 236 #endif  // PPAPI_PROXY_FILE_IO_RESOURCE_H_