net/websockets/websocket_deflate_parameters.h

   1 // Copyright 2015 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 NET_WEBSOCKETS_WEBSOCKET_DEFLATE_PARAMETERS_H_
   6 #define NET_WEBSOCKETS_WEBSOCKET_DEFLATE_PARAMETERS_H_
   7
   8 #include <stdint.h>
   9 #include <string>
  10
  11 #include "base/logging.h"
  12 #include "net/base/net_export.h"
  13 #include "net/websockets/websocket_deflater.h"
  14 #include "net/websockets/websocket_extension.h"
  15
  16 namespace net {
  17
  18 // A WebSocketDeflateParameters represents permessage-deflate extension
  19 // parameters. This class is used either for request and response.
  20 class NET_EXPORT_PRIVATE WebSocketDeflateParameters {
  21  public:
  22   using ContextTakeOverMode = WebSocketDeflater::ContextTakeOverMode;
  23
  24   // Returns a WebSocketExtension instance containing the parameters stored in
  25   // this object.
  26   WebSocketExtension AsExtension() const;
  27
  28   // Returns true when succeeded.
  29   // Returns false and stores the failure message to |failure_message|
  30   // otherwise.
  31   // Note that even if this function succeeds it is not guaranteed that the
  32   // object is valid. To check it, call IsValidAsRequest or IsValidAsResponse.
  33   bool Initialize(const WebSocketExtension& input,
  34                   std::string* failure_message);
  35
  36   // Returns true when |*this| and |response| are compatible.
  37   // |*this| must be valid as a request and |response| must be valid as a
  38   // response.
  39   bool IsCompatibleWith(const WebSocketDeflateParameters& response) const;
  40
  41   bool IsValidAsRequest(std::string* failure_message) const;
  42   bool IsValidAsResponse(std::string* failure_message) const;
  43   bool IsValidAsRequest() const {
  44     std::string message;
  45     return IsValidAsRequest(&message);
  46   }
  47   bool IsValidAsResponse() const {
  48     std::string message;
  49     return IsValidAsResponse(&message);
  50   }
  51
  52   ContextTakeOverMode server_context_take_over_mode() const {
  53     return server_context_take_over_mode_;
  54   }
  55   ContextTakeOverMode client_context_take_over_mode() const {
  56     return client_context_take_over_mode_;
  57   }
  58   bool is_server_max_window_bits_specified() const {
  59     return server_max_window_bits_.is_specified;
  60   }
  61   int server_max_window_bits() const {
  62     DCHECK(is_server_max_window_bits_specified());
  63     return server_max_window_bits_.bits;
  64   }
  65   bool is_client_max_window_bits_specified() const {
  66     return client_max_window_bits_.is_specified;
  67   }
  68   bool has_client_max_window_bits_value() const {
  69     DCHECK(is_client_max_window_bits_specified());
  70     return client_max_window_bits_.has_value;
  71   }
  72   int client_max_window_bits() const {
  73     DCHECK(has_client_max_window_bits_value());
  74     return client_max_window_bits_.bits;
  75   }
  76   void SetServerNoContextTakeOver() {
  77     server_context_take_over_mode_ =
  78         WebSocketDeflater::DO_NOT_TAKE_OVER_CONTEXT;
  79   }
  80   void SetClientNoContextTakeOver() {
  81     client_context_take_over_mode_ =
  82         WebSocketDeflater::DO_NOT_TAKE_OVER_CONTEXT;
  83   }
  84   // |bits| must be valid as a max_window_bits value.
  85   void SetServerMaxWindowBits(int bits) {
  86     DCHECK(IsValidWindowBits(bits));
  87     server_max_window_bits_ = WindowBits(bits, true, true);
  88   }
  89   void SetClientMaxWindowBits() {
  90     client_max_window_bits_ = WindowBits(0, true, false);
  91   }
  92   // |bits| must be valid as a max_window_bits value.
  93   void SetClientMaxWindowBits(int bits) {
  94     DCHECK(IsValidWindowBits(bits));
  95     client_max_window_bits_ = WindowBits(bits, true, true);
  96   }
  97
  98   // Return true if |bits| is valid as a max_window_bits value.
  99   static bool IsValidWindowBits(int bits) { return 8 <= bits && bits <= 15; }
 100
 101  private:
 102   struct WindowBits {
 103     WindowBits() : WindowBits(0, false, false) {}
 104     WindowBits(int16_t bits, bool is_specified, bool has_value)
 105         : bits(bits), is_specified(is_specified), has_value(has_value) {}
 106
 107     int16_t bits;
 108     // True when "window bits" parameter appears in the parameters.
 109     bool is_specified;
 110     // True when "window bits" parameter has the value.
 111     bool has_value;
 112   };
 113
 114   // |server_context_take_over_mode| is set to DO_NOT_TAKE_OVER_CONTEXT if and
 115   // only if |server_no_context_takeover| is set in the parameters.
 116   ContextTakeOverMode server_context_take_over_mode_ =
 117       WebSocketDeflater::TAKE_OVER_CONTEXT;
 118   // |client_context_take_over_mode| is set to DO_NOT_TAKE_OVER_CONTEXT if and
 119   // only if |client_no_context_takeover| is set in the parameters.
 120   ContextTakeOverMode client_context_take_over_mode_ =
 121       WebSocketDeflater::TAKE_OVER_CONTEXT;
 122   WindowBits server_max_window_bits_;
 123   WindowBits client_max_window_bits_;
 124 };
 125
 126 }  // namespace net
 127
 128 #endif  // NET_WEBSOCKETS_WEBSOCKET_DEFLATE_PARAMETERS_H_