Http cache: Fix handling of truncated entries.

- Always validate a truncated entry. Furthermore, given
that a server can say not-modified (304), followed  by
200 when actually asked for the final range, now we
validate truncated entries by asking for the next byte
that we need.

- If a server refuses to serve a byte range and instead
sends the whole resource, we just cache the response as
if nothing was stored before.

- If we receive a network error while reading from the
net, we don't discard the cached entry right away. Now
we wait until the transaction is closed, and attempt to
mark the entry as truncated.

BUG=48468
TEST=net_unittests

Review URL: http://codereview.chromium.org/6588105

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@76560 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 6 insertions, 0 deletions

diff --git a/net/http/partial_data.h b/net/http/partial_data.h
index 4726d10..6224fdf 100644
--- a/net/http/partial_data.h
+++ b/net/http/partial_data.h
@@ -75,6 +75,9 @@ class PartialData {
   bool UpdateFromStoredHeaders(const HttpResponseHeaders* headers,
                                disk_cache::Entry* entry, bool truncated);
 
+  // Sets the byte current range to start again at zero (for a truncated entry).
+  void SetRangeToStartDownload();
+
   // Returns true if the requested range is valid given the stored data.
   bool IsRequestedRangeOK();
 
@@ -110,6 +113,8 @@ class PartialData {
   // update the internal state about the current range.
   void OnNetworkReadCompleted(int result);
 
+  bool initial_validation() const { return initial_validation_; }
+
  private:
   class Core;
   // Returns the length to use when scanning the cache.
@@ -129,6 +134,7 @@ class PartialData {
   bool final_range_;
   bool sparse_entry_;
   bool truncated_;  // We have an incomplete 200 stored.
+  bool initial_validation_;  // Only used for truncated entries.
   Core* core_;
   CompletionCallback* callback_;