Add net::SdchSourceStream and net::SdchPolicyDelegate

net/filter/sdch_policy_delegate.h

+// Copyright 2016 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 NET_FILTER_SDCH_POLICY_DELEGATE_H_
+#define NET_FILTER_SDCH_POLICY_DELEGATE_H_
+
+#include <memory>
+#include <string>
+
+#include "base/macros.h"
+#include "base/supports_user_data.h"
+#include "net/base/net_export.h"
+#include "net/base/sdch_manager.h"
+#include "net/filter/sdch_source_stream.h"
+#include "net/log/net_log.h"
+#include "net/log/net_log_with_source.h"
+#include "url/gurl.h"
+
+namespace open_vcdiff {
+class VCDiffStreamingDecoder;
+}
+
+namespace net {
+
+class SdchSourceStream;
+
+// This class implements the SdchSourceStream::Delegate interface to perform
+// the SDCH error handling and stats gathering. The Context object supplies
+// details about the request needed for this object to make error-handling
+// decisions. See the SdchSourceStream::Delegate documentation for more details.
+class NET_EXPORT_PRIVATE SdchPolicyDelegate
+    : public SdchSourceStream::Delegate {
+ public:
+  enum StatisticSelector {
+    SDCH_DECODE,
+    SDCH_PASSTHROUGH,
+    SDCH_EXPERIMENT_DECODE,
+    SDCH_EXPERIMENT_HOLDBACK,
+  };
+
+  SdchPolicyDelegate(std::string mime_type,
+                     const GURL& url,
+                     bool is_cached_content,
+                     SdchManager* sdch_manager,
+                     std::unique_ptr<SdchManager::DictionarySet> dictionary_set,
+                     int response_code,
+                     const NetLogWithSource& net_log);
+
+  ~SdchPolicyDelegate() override;
+
+  // Logs an SDCH failure to UMA and |netlog|.
+  static void LogSdchProblem(NetLogWithSource netlog, SdchProblemCode problem);
+
+  // Sdch specific hacks to fix up encoding types.
+  static void FixUpSdchContentEncodings(
+      const NetLogWithSource& net_log,
+      const std::string& mime_type,
+      SdchManager::DictionarySet* dictionary_set,
+      std::vector<SourceStream::SourceType>* types);
+
+  // SdchSourceStream::Delegate implementation.
+  ErrorRecovery OnDictionaryIdError(bool possible_pass_through,
+                                    std::string* replace_output) override;
+  ErrorRecovery OnGetDictionaryError(bool possible_pass_through,
+                                     std::string* replace_output) override;
+  ErrorRecovery OnDecodingError(std::string* replace_output) override;
+  bool OnGetDictionary(const std::string& server_id,
+                       const std::string** text) override;
+
+  void OnStreamDestroyed(SdchSourceStream::InputState input_state,
+                         const std::string& buffered_output,
+                         open_vcdiff::VCDiffStreamingDecoder* decoder) override;
+
+ private:
+  // Disambiguate various types of responses that trigger a meta-refresh,
+  // failure, or fallback to pass-through.
+  enum ResponseCorruptionDetectionCause {
+    RESPONSE_NONE,
+
+    // 404 Http Response Code
+    RESPONSE_404 = 1,
+
+    // Not a 200 Http Response Code
+    RESPONSE_NOT_200 = 2,
+
+    // Cached before dictionary retrieved.
+    RESPONSE_OLD_UNENCODED = 3,
+
+    // Speculative but incorrect SDCH filtering was added added.
+    RESPONSE_TENTATIVE_SDCH = 4,
+
+    // Missing correct dict for decoding.
+    RESPONSE_NO_DICTIONARY = 5,
+
+    // Not an SDCH response but should be.
+    RESPONSE_CORRUPT_SDCH = 6,
+
+    // No dictionary was advertised with the request, the server claims
+    // to have encoded with SDCH anyway, but it isn't an SDCH response.
+    RESPONSE_ENCODING_LIE = 7,
+
+    RESPONSE_MAX,
+  };
+
+  // Issues a meta-refresh if the context's MIME type supports it, and returns
+  // whether a refresh was issued. As a side-effect, blacklists the context's
+  // domain either temporarily or permanently.
+  ErrorRecovery IssueMetaRefreshIfPossible(std::string* replace_output);
+
+  // Logs ResponseCorruptionDetection cause. This is very similar to
+  // LogSdchProblem(). TODO(xunjieli): Can we get rid of this?
+  void LogCorruptionDetection(ResponseCorruptionDetectionCause cause);
+
+  static const char* ResponseCorruptionDetectionCauseToString(
+      ResponseCorruptionDetectionCause cause);
+
+  static std::unique_ptr<base::Value> NetLogResponseCorruptionDetectionCallback(
+      ResponseCorruptionDetectionCause cause,
+      bool cached,
+      NetLogCaptureMode capture_mode);
+
+  const std::string mime_type_;
+  const GURL url_;
+  const bool is_cached_content_;
+  SdchManager* sdch_manager_;
+  std::unique_ptr<SdchManager::DictionarySet> dictionary_set_;
+  const int response_code_;
+  const NetLogWithSource net_log_;
+
+  std::string server_id_;
+
+  // If the response was encoded with a dictionary different than those
+  // advertised (e.g. a cached response using an old dictionary), this
+  // variable preserves that dictionary from deletion during decoding.
+  std::unique_ptr<SdchManager::DictionarySet> unexpected_dictionary_set_;
+
+  DISALLOW_COPY_AND_ASSIGN(SdchPolicyDelegate);
+};
+
+}  // namespace net
+
+#endif  // NET_FILTER_SDCH_POLICY_DELEGATE_H_