Http cache: Avoid resuming (and keeping) truncated entries

if the server doesn't provide a strong validator.

We require:
- A strong etag or a strong last modified date.
- The total Content length.
- Lack of an explicit rejection of ranges (Accept-ranges: none) 

This aligns better with the conditions used by Firefox.

BUG=30220, b/2329250
TEST=unittests

Review URL: http://codereview.chromium.org/517043

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@35761 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 10 insertions, 2 deletions

diff --git a/net/http/http_cache_transaction.cc b/net/http/http_cache_transaction.cc
index b829623..32808e8 100644
--- a/net/http/http_cache_transaction.cc
+++ b/net/http/http_cache_transaction.cc
@@ -548,6 +548,11 @@ bool HttpCache::Transaction::AddTruncatedFlag() {
   if (!entry_->disk_entry->GetDataSize(kResponseContentIndex))
     return false;
 
+  if (response_.headers->GetContentLength() <= 0 ||
+      response_.headers->HasHeaderValue("Accept-Ranges", "none") ||
+      !response_.headers->HasStrongValidators())
+    return false;
+
   truncated_ = true;
   target_state_ = STATE_NONE;
   next_state_ = STATE_CACHE_WRITE_TRUNCATED_RESPONSE;
@@ -1142,7 +1147,7 @@ bool HttpCache::Transaction::ConditionalizeRequest() {
     custom_request_->extra_headers.append("\r\n");
     // For byte-range requests, make sure that we use only one way to validate
     // the request.
-    if (partial_.get())
+    if (partial_.get() && !partial_->IsCurrentRangeCached())
       return true;
   }
 
@@ -1224,7 +1229,10 @@ bool HttpCache::Transaction::ValidatePartialResponse(
       return true;
     }
 
-    // 304 is not expected here, but we'll spare the entry.
+    // 304 is not expected here, but we'll spare the entry (unless it was
+    // truncated).
+    if (truncated_)
+      failure = true;
   }
 
   if (failure) {