Cleanup: have common HttpResponseHeaders routine to update with range

net/http/http_response_headers.cc

Index: net/http/http_response_headers.cc
diff --git a/net/http/http_response_headers.cc b/net/http/http_response_headers.cc
index f26292a08117a1791f1504cf4591884d801d011a..7a448e79c0e517c3a55e5a6d084fc67b28a431df 100644
--- a/net/http/http_response_headers.cc
+++ b/net/http/http_response_headers.cc
@@ -11,6 +11,7 @@
 
 #include <algorithm>
 
+#include "base/format_macros.h"
 #include "base/logging.h"
 #include "base/metrics/histogram.h"
 #include "base/pickle.h"
@@ -21,6 +22,7 @@
 #include "base/time/time.h"
 #include "base/values.h"
 #include "net/base/escape.h"
+#include "net/http/http_byte_range.h"
 #include "net/http/http_util.h"
 
 using base::StringPiece;
@@ -374,6 +376,30 @@ void HttpResponseHeaders::ReplaceStatusLine(const std::string& new_status) {
   MergeWithHeaders(new_raw_headers, empty_to_remove);
 }
 
+void HttpResponseHeaders::UpdateWithNewRange(
+    const HttpByteRange& byte_range,
+    int64 resource_size,
+    bool replace_status_line) {
+  DCHECK(byte_range.IsValid());

[mmenke, 2014/03/06 18:18:48]

Maybe add:

DCHECK(!byte_range.suffix_length());
DCHECK_NE(-1, byte_range.last_byte_position());

[rvargas (doing something else), 2014/03/06 19:24:00]

Excellent point. Now that this lives here we cannot assume where the byte range
comes from.

I think the checks that we need are actually
HasFirstBytePosition/HasLastBytePosition. That implies a valid, already bounded
range regardless of how it was originally created.

IsValid by itself accepts unbounded data, and having a suffix is ok as long as
the struct goes at some point through ComputeBounds, so using those checks here
is not appropriate.

[kinuko, 2014/03/07 05:05:14]

Added DCHECKs for HasFirstBytePosition/HasLastBytePosition. (I wasn't aware that
IsValid accepts unbounded range)

+
+  const char kLengthHeader[] = "Content-Length";
+  const char kRangeHeader[] = "Content-Range";
+
+  RemoveHeader(kLengthHeader);
+  RemoveHeader(kRangeHeader);
+
+  int64 start = byte_range.first_byte_position();
+  int64 end = byte_range.last_byte_position();
+  int64 range_len = end - start + 1;
+
+  if (replace_status_line)
+    ReplaceStatusLine("HTTP/1.1 206 Partial Content");
+
+  AddHeader(base::StringPrintf("%s: bytes %" PRId64 "-%" PRId64 "/%" PRId64,
+                               kRangeHeader, start, end, resource_size));
+  AddHeader(base::StringPrintf("%s: %" PRId64, kLengthHeader, range_len));
+}
+
 void HttpResponseHeaders::Parse(const std::string& raw_input) {
   raw_headers_.reserve(raw_input.size());