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 URLRequestHttpJob;
+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(bool possible_pass_through,
+                     URLRequestHttpJob* job,
+                     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;
+
+  // 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(std::string* replace_output) override;
+  ErrorRecovery OnGetDictionaryError(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:
+  // Issues a meta-refresh if the context's MIME type supports it, and returns
+  // whether a ErrorRecovery which should either be NONE (meta-refresh not
+  // issued) or REPLACE_OUTPUT (meta-refresh issued). For response not coming
+  // from the cache, the domain will be blacklisted as a side effect temporarily
+  // (for HTML payloads) or permanently (for non-HTML payloads).
+  ErrorRecovery IssueMetaRefreshIfPossible(std::string* replace_output);
+
+  // Set when SdchPolicyDelegate is used as a possible pass-through.

[Randy Smith (Not in Mondays), 2016/10/19 19:49:41]

nit: I'd say that it's actually the stream that's a possible pass through,
that's just managed from SdchPolicyDelegate.

[xunjieli, 2016/10/20 00:09:14]

Done.

+  const bool possible_pass_through_;
+
+  // Fields from URLRequestHttpJob.
+  const URLRequestHttpJob* job_;
+  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_