[BlobAsync] Patch 2: Common Constants

storage/common/data_element.cc

Index: storage/common/data_element.cc
diff --git a/storage/common/data_element.cc b/storage/common/data_element.cc
index f26058b7fb42875343474391d615fc11c2d546bf..c2e40c9a426643e92b12194cf74fd4bd57541a89 100644
--- a/storage/common/data_element.cc
+++ b/storage/common/data_element.cc
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include <iomanip>
+
 #include "storage/common/data_element.h"
 
 namespace storage {
@@ -52,4 +54,46 @@ void DataElement::SetToDiskCacheEntryRange(uint64 offset, uint64 length) {
   length_ = length;
 }
 
+std::ostream& operator<<(std::ostream& os, const DataElement& x) {
+  const uint64 kMaxDataPrintLength = 40;
+  os << "<DataElement>{type: ";
+  switch (x.type()) {
+    case DataElement::TYPE_BYTES: {
+      auto flags = os.flags();
+      os << "TYPE_BYTES, data: [" << std::hex;
+      uint64 length = std::min(x.length(), kMaxDataPrintLength);
+      for (size_t i = 0; i < length; i++) {
+        os << std::setfill('0') << std::setw(2) << +(x.bytes()[i]) << ' ';
+      }
+      os.flags(flags);
+      if (length < x.length()) {
+        os << "<...truncated due to length...>";
+      }
+      os << "]";
+      break;
+    }
+    case DataElement::TYPE_FILE:
+      os << "TYPE_FILE, path: " << x.path().AsUTF8Unsafe()
+         << ", expected_modification_time: " << x.expected_modification_time();
+      break;
+    case DataElement::TYPE_BLOB:
+      os << "TYPE_BLOB, uuid: " << x.blob_uuid();
+      break;
+    case DataElement::TYPE_FILE_FILESYSTEM:
+      os << "TYPE_FILE_FILESYSTEM, filesystem_url: " << x.filesystem_url();
+      break;
+    case DataElement::TYPE_DISK_CACHE_ENTRY:
+      os << "TYPE_DISK_CACHE_ENTRY";
+      break;
+    case DataElement::TYPE_BYTES_DESCRIPTION:
+      os << "TYPE_BYTES_DESCRIPTION";
+      break;
+    case DataElement::TYPE_UNKNOWN:
+      os << "TYPE_UNKNOWN";
+      break;
+  }
+  os << ", length: " << x.length() << ", offset: " << x.offset() << "}";
+  return os;
+}
+
 }  // namespace storage