Doom and create new entry when validation is not a match

net/http/http_cache_transaction.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.
 
 // This file declares HttpCache::Transaction, a private class of HttpCache so
 // it should only be included by http_cache.cc
 
 #ifndef NET_HTTP_HTTP_CACHE_TRANSACTION_H_
 #define NET_HTTP_HTTP_CACHE_TRANSACTION_H_
 
@@ skipping 462 matching lines @@
   Mode mode_;
   Mode original_mode_;  // Used when restarting the transaction.
   bool reading_;  // We are already reading. Never reverts to false once set.
   bool invalid_range_;  // We may bypass the cache for this request.
   bool truncated_;  // We don't have all the response data.
   bool is_sparse_;  // The data is stored in sparse byte ranges.
   bool range_requested_;  // The user requested a byte range.
   bool handling_206_;  // We must deal with this 206 response.
   bool cache_pending_;  // We are waiting for the HttpCache.
   bool done_reading_;  // All available data was read.
+  bool done_headers_;  // Headers have been received from the network.

[Randy Smith (Not in Mondays), 2017/04/04 21:54:03]

Alternative design--I'm not sure this is a good idea, I'm raising it in a
brainstorming mode: done_headers_ is in some ways a state variable--it's saying
"This transaction already has a request attached to it on which full data for
this entry is incoming."  This CL is using that variable for tweaking behavior
in the CREATE_ENTRY, ADD_TRANSACTION_TO_ENTRY, and
ADD_TRANSACTION_TO_ENTRY_COMPLETE states.  An alternative design would be to
duplicate those three states for the doom-and-create path.  I think the code for
those three state functions would be simpler than the ones it would be copied
from (no range requests, no bypass_lock_for_test_), and if thinking about the
operation of this class at the state machine abstraction, I think it would be
simpler and clearer.  WDYT?

[shivanisha, 2017/04/07 23:24:13]

done_headers_ is used in CREATE_ENTRY_COMPLETE and ADD_TO_ENTRY_COMPLETE.
Created a DONE_HEADERS_ADD_TO_ENTRY_COMPLETE state since that's the state which
differs the most from the original ADD_TO_ENTRY_COMPLETE state. Renamed
done_headers_ to done_headers_create_new_entry_ to be more specific of its
purpose and also included its resetting after use.

   bool vary_mismatch_;  // The request doesn't match the stored vary data.
   bool couldnt_conditionalize_request_;
   bool bypass_lock_for_test_;  // A test is exercising the cache lock.
   bool fail_conditionalization_for_test_;  // Fail ConditionalizeRequest.
   bool validating_cannot_proceed_;
   scoped_refptr<IOBuffer> read_buf_;
   int io_buf_len_;
   int read_offset_;
   int effective_load_flags_;
   int write_len_;
@@ skipping 39 matching lines @@
   bool in_do_loop_;
 
   base::WeakPtrFactory<Transaction> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(Transaction);
 };
 
 }  // namespace net
 
 #endif  // NET_HTTP_HTTP_CACHE_TRANSACTION_H_