Http Cache: Add support for resuming downloading a...

net/http/partial_data.h

 // Copyright (c) 2009 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_HTTP_PARTIAL_DATA_H_
 #define NET_HTTP_PARTIAL_DATA_H_
 
 #include <string>
 
 #include "base/basictypes.h"
@@ skipping 14 matching lines @@
 // these requests. This class is tightly integrated with HttpCache::Transaction
 // and it is intended to allow a cleaner implementation of that class.
 //
 // In order to fulfill range requests, we may have to perform a sequence of
 // reads from the cache, interleaved with reads from the network / writes to the
 // cache. This class basically keeps track of the data required to perform each
 // of those individual network / cache requests.
 class PartialData {
  public:
   PartialData()
-      : range_present_(false), final_range_(false), sparse_entry_(true) {}
+      : range_present_(false), final_range_(false), sparse_entry_(true),
+        truncated_(false) {}
   ~PartialData() {}
 
   // Performs initialization of the object by parsing the request |headers|
   // and verifying that we can process the requested range. Returns true if
   // we can process the requested range, and false otherwise. |new_headers| is
   // a subset of the request extra headers, with byte-range related headers
   // removed so that we can easily add any byte-range that we need.
   bool Init(const std::string& headers, const std::string& new_headers);
 
   // Restores the byte-range header that was removed during Init(), by appending
   // the data to the provided |headers|.
   void RestoreHeaders(std::string* headers) const;
 
   // Builds the required |headers| to perform the proper cache validation for
   // the next range to be fetched. Returns 0 when there is no need to perform
   // more operations because we reached the end of the request (so 0 bytes
   // should be actually returned to the user), a positive number to indicate
   // that |headers| should be used to validate the cache, or an appropriate
   // error code.
   int PrepareCacheValidation(disk_cache::Entry* entry, std::string* headers);
 
   // Returns true if the current range is stored in the cache.
   bool IsCurrentRangeCached() const;
 
   // Returns true if the current range is the last one needed to fulfill the
   // user's request.
   bool IsLastRange() const;
 
   // Extracts info from headers already stored in the cache. Returns false if
-  // there is any problem with the headers.
+  // there is any problem with the headers. |truncated| should be true if we
+  // have an incomplete 200 entry.
   bool UpdateFromStoredHeaders(const HttpResponseHeaders* headers,
-                               disk_cache::Entry* entry);
+                               disk_cache::Entry* entry, bool truncated);
 
   // Returns true if the requested range is valid given the stored data.
   bool IsRequestedRangeOK();
 
   // Returns true if the response headers match what we expect, false otherwise.
   bool ResponseHeadersOK(const HttpResponseHeaders* headers);
 
   // Fixes the response headers to include the right content length and range.
   void FixResponseHeaders(HttpResponseHeaders* headers);
 
@@ skipping 26 matching lines @@
 
   int64 current_range_start_;
   int64 cached_start_;
   int64 resource_size_;
   int cached_min_len_;
   HttpByteRange byte_range_;  // The range requested by the user.
   std::string extra_headers_;  // The clean set of extra headers (no ranges).
   bool range_present_;  // True if next range entry is already stored.
   bool final_range_;
   bool sparse_entry_;
+  bool truncated_;  // We have an incomplete 200 stored.
 
   DISALLOW_COPY_AND_ASSIGN(PartialData);
 };
 
 }  // namespace net
 
 #endif  // NET_HTTP_PARTIAL_DATA_H_