Http cache: Add support for ranges with an unknown start or end.

BUG=12258
TEST=unittest

Review URL: http://codereview.chromium.org/147042

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@19142 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 31 insertions, 19 deletions

diff --git a/net/http/partial_data.cc b/net/http/partial_data.cc
index 13cb377..8d56966 100644
--- a/net/http/partial_data.cc
+++ b/net/http/partial_data.cc
@@ -35,18 +35,16 @@ bool PartialData::Init(const std::string& headers,
   extra_headers_ = new_headers;
   resource_size_ = 0;
 
-  // TODO(rvargas): Handle requests without explicit start or end.
-  DCHECK(byte_range_.HasFirstBytePosition());
   current_range_start_ = byte_range_.first_byte_position();
   return true;
 }
 
 void PartialData::RestoreHeaders(std::string* headers) const {
-  DCHECK(current_range_start_ >= 0);
+  DCHECK(current_range_start_ >= 0 || byte_range_.IsSuffixByteRange());
+  int64 end = byte_range_.IsSuffixByteRange() ?
+              byte_range_.suffix_length() : byte_range_.last_byte_position();
 
-  // TODO(rvargas): Handle requests without explicit start or end.
-  AddRangeHeader(current_range_start_, byte_range_.last_byte_position(),
-                 headers);
+  AddRangeHeader(current_range_start_, end, headers);
 }
 
 int PartialData::PrepareCacheValidation(disk_cache::Entry* entry,
@@ -102,18 +100,22 @@ bool PartialData::IsLastRange() const {
   return final_range_;
 }
 
-void PartialData::UpdateFromStoredHeaders(const HttpResponseHeaders* headers) {
+bool PartialData::UpdateFromStoredHeaders(const HttpResponseHeaders* headers) {
   std::string length_value;
-  if (!headers->GetNormalizedHeader(kLengthHeader, &length_value)) {
-    // We must have stored the resource length.
-    NOTREACHED();
-    resource_size_ = 0;
-    return;
-  }
-  if (!StringToInt64(length_value, &resource_size_)) {
-    NOTREACHED();
-    resource_size_ = 0;
-  }
+  resource_size_ = 0;
+  if (!headers->GetNormalizedHeader(kLengthHeader, &length_value))
+    return false;  // We must have stored the resource length.
+
+  if (!StringToInt64(length_value, &resource_size_))
+    return false;
+
+  if (resource_size_ && !byte_range_.ComputeBounds(resource_size_))
+    return false;
+
+  if (current_range_start_ < 0)
+    current_range_start_ = byte_range_.first_byte_position();
+
+  return current_range_start_ >= 0;
 }
 
 bool PartialData::ResponseHeadersOK(const HttpResponseHeaders* headers) {
@@ -126,8 +128,10 @@ bool PartialData::ResponseHeadersOK(const HttpResponseHeaders* headers) {
   if (!resource_size_) {
     // First response. Update our values with the ones provided by the server.
     resource_size_ = total_length;
-    if (!byte_range_.HasFirstBytePosition())
+    if (!byte_range_.HasFirstBytePosition()) {
       byte_range_.set_first_byte_position(start);
+      current_range_start_ = start;
+    }
     if (!byte_range_.HasLastBytePosition())
       byte_range_.set_last_byte_position(end);
   } else if (resource_size_ != total_length) {
@@ -199,7 +203,15 @@ void PartialData::OnNetworkReadCompleted(int result) {
 
 // Static.
 void PartialData::AddRangeHeader(int64 start, int64 end, std::string* headers) {
-  headers->append(StringPrintf("Range: bytes=%lld-%lld\r\n", start, end));
+  DCHECK(start >= 0 || end >= 0);
+  std::string my_start, my_end;
+  if (start >= 0)
+    my_start = Int64ToString(start);
+  if (end >= 0)
+    my_end = Int64ToString(end);
+
+  headers->append(StringPrintf("Range: bytes=%s-%s\r\n", my_start.c_str(),
+                               my_end.c_str()));
 }