Suppress pause-and-buffer behavior when the HTTP response won't satisfy future requests via cache.

BUG=123074


Review URL: https://chromiumcodereview.appspot.com/10387200

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@138972 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 49 insertions, 26 deletions

diff --git a/net/http/http_response_headers.cc b/net/http/http_response_headers.cc
index 33d78da..c03fbe9 100644
--- a/net/http/http_response_headers.cc
+++ b/net/http/http_response_headers.cc
@@ -1160,32 +1160,16 @@ bool HttpResponseHeaders::IsKeepAlive() const {
 }
 
 bool HttpResponseHeaders::HasStrongValidators() const {
-  if (GetHttpVersion() < HttpVersion(1, 1))
-    return false;
-
-  std::string etag_value;
-  EnumerateHeader(NULL, "etag", &etag_value);
-  if (!etag_value.empty()) {
-    size_t slash = etag_value.find('/');
-    if (slash == std::string::npos || slash == 0)
-      return true;
-
-    std::string::const_iterator i = etag_value.begin();
-    std::string::const_iterator j = etag_value.begin() + slash;
-    HttpUtil::TrimLWS(&i, &j);
-    if (!LowerCaseEqualsASCII(i, j, "w"))
-      return true;
-  }
-
-  Time last_modified;
-  if (!GetLastModifiedValue(&last_modified))
-    return false;
-
-  Time date;
-  if (!GetDateValue(&date))
-    return false;
-
-  return ((date - last_modified).InSeconds() >= 60);
+  std::string etag_header;
+  EnumerateHeader(NULL, "etag", &etag_header);
+  std::string last_modified_header;
+  EnumerateHeader(NULL, "Last-Modified", &last_modified_header);
+  std::string date_header;
+  EnumerateHeader(NULL, "Date", &date_header);
+  return HttpUtil::HasStrongValidators(GetHttpVersion(),
+                                       etag_header,
+                                       last_modified_header,
+                                       date_header);
 }
 
 // From RFC 2616:
diff --git a/net/http/http_util.cc b/net/http/http_util.cc
index a5dc391..0a9c6a6 100644
--- a/net/http/http_util.cc
+++ b/net/http/http_util.cc
@@ -15,6 +15,7 @@
 #include "base/string_number_conversions.h"
 #include "base/string_piece.h"
 #include "base/string_util.h"
+#include "base/time.h"
 
 using std::string;
 
@@ -699,6 +700,36 @@ void HttpUtil::AppendHeaderIfMissing(const char* header_name,
   *headers += std::string(header_name) + ": " + header_value + "\r\n";
 }
 
+bool HttpUtil::HasStrongValidators(HttpVersion version,
+                                   const std::string& etag_header,
+                                   const std::string& last_modified_header,
+                                   const std::string& date_header) {
+  if (version < HttpVersion(1, 1))
+    return false;
+
+  if (!etag_header.empty()) {
+    size_t slash = etag_header.find('/');
+    if (slash == std::string::npos || slash == 0)
+      return true;
+
+    std::string::const_iterator i = etag_header.begin();
+    std::string::const_iterator j = etag_header.begin() + slash;
+    TrimLWS(&i, &j);
+    if (!LowerCaseEqualsASCII(i, j, "w"))
+      return true;
+  }
+
+  base::Time last_modified;
+  if (!base::Time::FromString(last_modified_header.c_str(), &last_modified))
+    return false;
+
+  base::Time date;
+  if (!base::Time::FromString(date_header.c_str(), &date))
+    return false;
+
+  return ((date - last_modified).InSeconds() >= 60);
+}
+
 // BNF from section 4.2 of RFC 2616:
 //
 //   message-header = field-name ":" [ field-value ]
diff --git a/net/http/http_util.h b/net/http/http_util.h
index 57aa0d0..0801382 100644
--- a/net/http/http_util.h
+++ b/net/http/http_util.h
@@ -14,6 +14,7 @@
 #include "googleurl/src/gurl.h"
 #include "net/base/net_export.h"
 #include "net/http/http_byte_range.h"
+#include "net/http/http_version.h"
 
 // This is a macro to support extending this string literal at compile time.
 // Please excuse me polluting your global namespace!
@@ -187,6 +188,13 @@ class NET_EXPORT HttpUtil {
                                     const std::string& header_value,
                                     std::string* headers);
 
+  // Returns true if the parameters describe a response with a strong etag or
+  // last-modified header.  See section 13.3.3 of RFC 2616.
+  static bool HasStrongValidators(HttpVersion version,
+                                  const std::string& etag_header,
+                                  const std::string& last_modified_header,
+                                  const std::string& date_header);
+
   // Used to iterate over the name/value pairs of HTTP headers.  To iterate
   // over the values in a multi-value header, use ValuesIterator.
   // See AssembleRawHeaders for joining line continuations (this iterator