ppapi/native_client/src/trusted/plugin/file_downloader.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 NATIVE_CLIENT_SRC_TRUSTED_PLUGIN_FILE_DOWNLOADER_H_
   6 #define NATIVE_CLIENT_SRC_TRUSTED_PLUGIN_FILE_DOWNLOADER_H_
   7
   8 #include <deque>
   9
  10 #include "native_client/src/include/nacl_macros.h"
  11 #include "native_client/src/include/nacl_string.h"
  12 #include "native_client/src/trusted/validator/nacl_file_info.h"
  13 #include "ppapi/c/private/pp_file_handle.h"
  14 #include "ppapi/c/trusted/ppb_file_io_trusted.h"
  15 #include "ppapi/c/trusted/ppb_url_loader_trusted.h"
  16 #include "ppapi/cpp/file_io.h"
  17 #include "ppapi/cpp/instance.h"
  18 #include "ppapi/cpp/url_loader.h"
  19 #include "ppapi/cpp/url_response_info.h"
  20 #include "ppapi/native_client/src/trusted/plugin/callback_source.h"
  21 #include "ppapi/utility/completion_callback_factory.h"
  22
  23 namespace plugin {
  24
  25 class Plugin;
  26
  27 typedef enum {
  28   DOWNLOAD_TO_FILE = 0,
  29   DOWNLOAD_TO_BUFFER,
  30   DOWNLOAD_STREAM,
  31   DOWNLOAD_NONE
  32 } DownloadMode;
  33
  34 typedef enum {
  35   SCHEME_CHROME_EXTENSION,
  36   SCHEME_DATA,
  37   SCHEME_OTHER
  38 } UrlSchemeType;
  39
  40 typedef std::vector<char>* FileStreamData;
  41 typedef CallbackSource<FileStreamData> StreamCallbackSource;
  42 typedef pp::CompletionCallbackWithOutput<FileStreamData> StreamCallback;
  43
  44 // A class that wraps PPAPI URLLoader and FileIO functionality for downloading
  45 // the url into a file and providing an open file descriptor.
  46 class FileDownloader {
  47  public:
  48   // Ctor initializes |instance_| to NULL, be sure to call Initialize() before
  49   // calling Open(), or Open() will fail.
  50   FileDownloader()
  51       : instance_(NULL),
  52         file_open_notify_callback_(pp::BlockUntilComplete()),
  53         stream_finish_callback_(pp::BlockUntilComplete()),
  54         file_handle_(PP_kInvalidFileHandle),
  55         file_io_trusted_interface_(NULL),
  56         url_loader_trusted_interface_(NULL),
  57         open_time_(-1),
  58         mode_(DOWNLOAD_NONE),
  59         open_and_stream_(true),
  60         url_scheme_(SCHEME_OTHER),
  61         data_stream_callback_source_(NULL) {}
  62   ~FileDownloader() {}
  63
  64   // Initialize() can only be called once during the lifetime of this instance.
  65   void Initialize(Plugin* instance);
  66
  67   // Issues a GET on |url| to start downloading the response into a file,
  68   // and finish streaming it. |callback| will be run after streaming is
  69   // done or if an error prevents streaming from completing.
  70   // Returns true when callback is scheduled to be called on success or failure.
  71   // Returns false if callback is NULL, Initialize() has not been called or if
  72   // the PPB_FileIO_Trusted interface is not available.
  73   // If |record_progress| is true, then download progress will be recorded,
  74   // and can be polled through GetDownloadProgress().
  75   // If |progress_callback| is not NULL and |record_progress| is true,
  76   // then the callback will be invoked for every progress update received
  77   // by the loader.
  78   bool Open(const nacl::string& url,
  79             DownloadMode mode,
  80             const pp::CompletionCallback& callback,
  81             bool record_progress,
  82             PP_URLLoaderTrusted_StatusCallback progress_callback);
  83
  84   // Similar to Open(), but used for streaming the |url| data directly to the
  85   // caller without writing to a temporary file. The callbacks provided by
  86   // |stream_callback_source| are expected to copy the data before returning.
  87   // |callback| is called once the response headers are received,
  88   // and streaming must be completed separately via FinishStreaming().
  89   bool OpenStream(const nacl::string& url,
  90                   const pp::CompletionCallback& callback,
  91                   StreamCallbackSource* stream_callback_source);
  92
  93   // Finish streaming the response body for a URL request started by either
  94   // Open() or OpenStream().  If DownloadMode is DOWNLOAD_TO_FILE,
  95   // then the response body is streamed to a file, the file is opened and
  96   // a file descriptor is made available.  Runs the given |callback| when
  97   // streaming is done.
  98   void FinishStreaming(const pp::CompletionCallback& callback);
  99
 100   // Bypasses downloading and takes a handle to the open file. To get the fd,
 101   // call GetFileInfo().
 102   void OpenFast(const nacl::string& url, PP_FileHandle file_handle,
 103                 uint64_t file_token_lo, uint64_t file_token_hi);
 104
 105   // Return a structure describing the file opened, including a file desc.
 106   // If downloading and opening succeeded, this returns a valid read-only
 107   // POSIX file descriptor.  On failure, the return value is an invalid
 108   // descriptor.  The file descriptor is owned by this instance, so the
 109   // delegate does not have to close it.
 110   struct NaClFileInfo GetFileInfo();
 111
 112   // Returns the time delta between the call to Open() and this function.
 113   int64_t TimeSinceOpenMilliseconds() const;
 114
 115   // The value of |url_| changes over the life of this instance.  When the file
 116   // is first opened, |url_| is a copy of the URL used to open the file, which
 117   // can be a relative URL.  Once the GET request has finished, and the contents
 118   // of the file represented by |url_| are available, |url_| is the full URL
 119   // including the scheme, host and full path.
 120   const nacl::string& url() const { return url_; }
 121
 122   // Returns the url passed to Open().
 123   const nacl::string& url_to_open() const { return url_to_open_; }
 124
 125   // Returns the PP_Resource of the active URL loader, or kInvalidResource.
 126   PP_Resource url_loader() const { return url_loader_.pp_resource(); }
 127
 128   // GetDownloadProgress() returns the current download progress, which is
 129   // meaningful after Open() has been called. Progress only refers to the
 130   // response body and does not include the headers.
 131   //
 132   // This data is only available if the |record_progress| true in the
 133   // Open() call.  If progress is being recorded, then |bytes_received|
 134   // will be set to the number of bytes received thus far,
 135   // and |total_bytes_to_be_received| will be set to the total number
 136   // of bytes to be received.  The total bytes to be received may be unknown,
 137   // in which case |total_bytes_to_be_received| will be set to -1.
 138   bool GetDownloadProgress(int64_t* bytes_received,
 139                            int64_t* total_bytes_to_be_received) const;
 140
 141   // Returns the buffer used for DOWNLOAD_TO_BUFFER mode.
 142   const std::deque<char>& buffer() const { return buffer_; }
 143
 144   bool streaming_to_file() const;
 145   bool streaming_to_buffer() const;
 146   bool streaming_to_user() const;
 147   bool not_streaming() const;
 148
 149   int status_code() const { return status_code_; }
 150   nacl::string GetResponseHeaders() const;
 151
 152  private:
 153   NACL_DISALLOW_COPY_AND_ASSIGN(FileDownloader);
 154   // This class loads and opens the file in three steps for DOWNLOAD_TO_FILE:
 155   //   1) Ask the browser to start streaming |url_| as a file.
 156   //   2) Ask the browser to finish streaming if headers indicate success.
 157   //   3) Ask the browser to open the file, so we can get the file descriptor.
 158   // For DOWNLOAD_TO_BUFFER, the process is very similar:
 159   //   1) Ask the browser to start streaming |url_| to an internal buffer.
 160   //   2) Ask the browser to finish streaming to |temp_buffer_| on success.
 161   //   3) Wait for streaming to finish, filling |buffer_| incrementally.
 162   // Each step is done asynchronously using callbacks.  We create callbacks
 163   // through a factory to take advantage of ref-counting.
 164   // DOWNLOAD_STREAM is similar to DOWNLOAD_TO_BUFFER except the downloaded
 165   // data is passed directly to the user instead of saved in a buffer.
 166   // The public Open*() functions start step 1), and the public FinishStreaming
 167   // function proceeds to step 2) and 3).
 168   bool InitialResponseIsValid(int32_t pp_error);
 169   void URLLoadStartNotify(int32_t pp_error);
 170   void URLLoadFinishNotify(int32_t pp_error);
 171   void URLBufferStartNotify(int32_t pp_error);
 172   void URLReadBodyNotify(int32_t pp_error);
 173   void StreamFinishNotify(int32_t pp_error);
 174
 175   Plugin* instance_;
 176   nacl::string url_to_open_;
 177   nacl::string url_;
 178   pp::URLResponseInfo url_response_;
 179   pp::CompletionCallback file_open_notify_callback_;
 180   pp::CompletionCallback stream_finish_callback_;
 181   pp::FileIO file_reader_;
 182   PP_FileHandle file_handle_;
 183   struct NaClFileToken file_token_;
 184   const PPB_FileIOTrusted* file_io_trusted_interface_;
 185   const PPB_URLLoaderTrusted* url_loader_trusted_interface_;
 186   pp::URLLoader url_loader_;
 187   pp::CompletionCallbackFactory<FileDownloader> callback_factory_;
 188   int64_t open_time_;
 189   int32_t status_code_;
 190   DownloadMode mode_;
 191   bool open_and_stream_;
 192   static const uint32_t kTempBufferSize = 2048;
 193   std::vector<char> temp_buffer_;
 194   std::deque<char> buffer_;
 195   UrlSchemeType url_scheme_;
 196   StreamCallbackSource* data_stream_callback_source_;
 197 };
 198 }  // namespace plugin;
 199 #endif  // NATIVE_CLIENT_SRC_TRUSTED_PLUGIN_FILE_DOWNLOADER_H_