Use HTTP response headers for PNaCl caching instead of bitcode hash.

ppapi/native_client/src/trusted/plugin/file_downloader.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef NATIVE_CLIENT_SRC_TRUSTED_PLUGIN_FILE_DOWNLOADER_H_
 #define NATIVE_CLIENT_SRC_TRUSTED_PLUGIN_FILE_DOWNLOADER_H_
 
 #include <deque>
 
 #include "native_client/src/include/nacl_macros.h"
 #include "native_client/src/include/nacl_string.h"
 #include "native_client/src/trusted/plugin/callback_source.h"
 #include "native_client/src/trusted/validator/nacl_file_info.h"
 #include "ppapi/c/private/pp_file_handle.h"
 #include "ppapi/c/trusted/ppb_file_io_trusted.h"
 #include "ppapi/c/trusted/ppb_url_loader_trusted.h"
 #include "ppapi/cpp/file_io.h"
+#include "ppapi/cpp/instance.h"
 #include "ppapi/cpp/url_loader.h"
-#include "ppapi/cpp/instance.h"
+#include "ppapi/cpp/url_response_info.h"
 #include "ppapi/utility/completion_callback_factory.h"
 
 namespace plugin {
 
 class Plugin;
 
 typedef enum {
   DOWNLOAD_TO_FILE = 0,
   DOWNLOAD_TO_BUFFER,
   DOWNLOAD_STREAM,
@@ skipping 12 matching lines @@
 
 // A class that wraps PPAPI URLLoader and FileIO functionality for downloading
 // the url into a file and providing an open file descriptor.
 class FileDownloader {
  public:
   // Ctor initializes |instance_| to NULL, be sure to call Initialize() before
   // calling Open(), or Open() will fail.
   FileDownloader()
       : instance_(NULL),
         file_open_notify_callback_(pp::BlockUntilComplete()),
+        stream_finish_callback_(pp::BlockUntilComplete()),
         file_handle_(PP_kInvalidFileHandle),
         file_io_trusted_interface_(NULL),
         url_loader_trusted_interface_(NULL),
         open_time_(-1),
         mode_(DOWNLOAD_NONE),
+        open_and_stream_(true),
         url_scheme_(SCHEME_OTHER),
         data_stream_callback_source_(NULL) {}
   ~FileDownloader() {}
 
   // Initialize() can only be called once during the lifetime of this instance.
   void Initialize(Plugin* instance);
 
-  // Issues a GET on |url| downloading the response into a file. The file is
-  // then opened and a file descriptor is made available.
+  // Issues a GET on |url| to start downloading the response into a file,
+  // and finish streaming it. |callback| will be run after streaming is
+  // done or if an error prevents streaming from completing.
   // Returns true when callback is scheduled to be called on success or failure.
   // Returns false if callback is NULL, Initialize() has not been called or if
   // the PPB_FileIO_Trusted interface is not available.
   // If |record_progress| is true, then download progress will be recorded,
   // and can be polled through GetDownloadProgress().
   // If |progress_callback| is not NULL and |record_progress| is true,
   // then the callback will be invoked for every progress update received
   // by the loader.
   bool Open(const nacl::string& url,
             DownloadMode mode,
             const pp::CompletionCallback& callback,
             bool record_progress,
             PP_URLLoaderTrusted_StatusCallback progress_callback);
 
-  // Same as Open, but used for streaming the file data directly to the
-  // caller without buffering it. The callbacks provided by
+  // Similar to Open(), but used for streaming the |url| data directly to the
+  // caller without writing to a temporary file. The callbacks provided by
   // |stream_callback_source| are expected to copy the data before returning.
-  // |callback| will still be called when the stream is finished.
+  // |callback| is called once the response headers are received,
+  // and streaming must be completed separately via FinishStreaming().
   bool OpenStream(const nacl::string& url,
                   const pp::CompletionCallback& callback,
                   StreamCallbackSource* stream_callback_source);
 
+  // Finish streaming the response body for a URL request started by either
+  // Open() or OpenStream().  If DownloadMode is DOWNLOAD_TO_FILE,
+  // then the response body is streamed to a file, the file is opened and
+  // a file descriptor is made available.  Runs the given |callback| when
+  // streaming is done.
+  void FinishStreaming(const pp::CompletionCallback& callback);
+
   // Bypasses downloading and takes a handle to the open file. To get the fd,
   // call GetFileInfo().
   void OpenFast(const nacl::string& url, PP_FileHandle file_handle,
                 uint64_t file_token_lo, uint64_t file_token_hi);
 
   // Return a structure describing the file opened, including a file desc.
   // If downloading and opening succeeded, this returns a valid read-only
   // POSIX file descriptor.  On failure, the return value is an invalid
   // descriptor.  The file descriptor is owned by this instance, so the
   // delegate does not have to close it.
@@ skipping 30 matching lines @@
 
   // Returns the buffer used for DOWNLOAD_TO_BUFFER mode.
   const std::deque<char>& buffer() const { return buffer_; }
 
   bool streaming_to_file() const;
   bool streaming_to_buffer() const;
   bool streaming_to_user() const;
   bool not_streaming() const;
 
   int status_code() const { return status_code_; }
+  nacl::string GetResponseHeaders() const;
 
  private:
   NACL_DISALLOW_COPY_AND_ASSIGN(FileDownloader);
   // This class loads and opens the file in three steps for DOWNLOAD_TO_FILE:
   //   1) Ask the browser to start streaming |url_| as a file.
   //   2) Ask the browser to finish streaming if headers indicate success.
   //   3) Ask the browser to open the file, so we can get the file descriptor.
   // For DOWNLOAD_TO_BUFFER, the process is very similar:
   //   1) Ask the browser to start streaming |url_| to an internal buffer.
   //   2) Ask the browser to finish streaming to |temp_buffer_| on success.
   //   3) Wait for streaming to finish, filling |buffer_| incrementally.
   // Each step is done asynchronously using callbacks.  We create callbacks
   // through a factory to take advantage of ref-counting.
   // DOWNLOAD_STREAM is similar to DOWNLOAD_TO_BUFFER except the downloaded
   // data is passed directly to the user instead of saved in a buffer.
+  // The public Open*() functions start step 1), and the public FinishStreaming
+  // function proceeds to step 2) and 3).
   bool InitialResponseIsValid(int32_t pp_error);
   void URLLoadStartNotify(int32_t pp_error);
   void URLLoadFinishNotify(int32_t pp_error);
   void URLBufferStartNotify(int32_t pp_error);
   void URLReadBodyNotify(int32_t pp_error);
-  void FileOpenNotify(int32_t pp_error);
+  void StreamFinishNotify(int32_t pp_error);
 
   Plugin* instance_;
   nacl::string url_to_open_;
   nacl::string url_;
+  pp::URLResponseInfo url_response_;
   pp::CompletionCallback file_open_notify_callback_;
+  pp::CompletionCallback stream_finish_callback_;
   pp::FileIO file_reader_;
   PP_FileHandle file_handle_;
   struct NaClFileToken file_token_;
   const PPB_FileIOTrusted* file_io_trusted_interface_;
   const PPB_URLLoaderTrusted* url_loader_trusted_interface_;
   pp::URLLoader url_loader_;
   pp::CompletionCallbackFactory<FileDownloader> callback_factory_;
   int64_t open_time_;
   int32_t status_code_;
   DownloadMode mode_;
+  bool open_and_stream_;
   static const uint32_t kTempBufferSize = 2048;
   std::vector<char> temp_buffer_;
   std::deque<char> buffer_;
   UrlSchemeType url_scheme_;
   StreamCallbackSource* data_stream_callback_source_;
 };
 }  // namespace plugin;
 #endif  // NATIVE_CLIENT_SRC_TRUSTED_PLUGIN_FILE_DOWNLOADER_H_