Expose the ValueSerializer data format version as a compile-time constant.

BUG=chromium:704293

Review-Url: https://codereview.chromium.org/2804643006
Cr-Commit-Position: refs/heads/master@{#44945}

BUILD.gn

@@ -1012,6 +1012,7 @@ v8_header_set("v8_version") {
   configs = [ ":internal_config" ]
 
   sources = [
+    "include/v8-value-serializer-version.h",
     "include/v8-version-string.h",
     "include/v8-version.h",
   ]

include/v8-value-serializer-version.h

@@ -0,0 +1,24 @@
+// Copyright 2017 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+/**
+ * Compile-time constants.
+ *
+ * This header provides access to information about the value serializer at
+ * compile time, without declaring or defining any symbols that require linking
+ * to V8.
+ */
+
+#ifndef INCLUDE_V8_VALUE_SERIALIZER_VERSION_H_
+#define INCLUDE_V8_VALUE_SERIALIZER_VERSION_H_
+
+#include <stdint.h>
+
+namespace v8 {
+
+constexpr uint32_t CurrentValueSerializerFormatVersion() { return 13; }
+
+}  // namespace v8
+
+#endif  // INCLUDE_V8_VALUE_SERIALIZER_VERSION_H_

include/v8.h

@@ -1793,8 +1793,6 @@ class V8_EXPORT ValueSerializer {
     virtual void FreeBufferMemory(void* buffer);
   };
 
-  static uint32_t GetCurrentDataFormatVersion();
-
   explicit ValueSerializer(Isolate* isolate);
   ValueSerializer(Isolate* isolate, Delegate* delegate);
   ~ValueSerializer();

src/api.cc

@@ -3215,11 +3215,6 @@ struct ValueSerializer::PrivateData {
   i::ValueSerializer serializer;
 };
 
-// static
-uint32_t ValueSerializer::GetCurrentDataFormatVersion() {
-  return i::ValueSerializer::GetCurrentDataFormatVersion();
-}
-
 ValueSerializer::ValueSerializer(Isolate* isolate)
     : ValueSerializer(isolate, nullptr) {}
 

src/v8.gyp

@@ -389,6 +389,7 @@
         '../include/v8-profiler.h',
         '../include/v8-testing.h',
         '../include/v8-util.h',
+        '../include/v8-value-serializer-version.h',
         '../include/v8-version-string.h',
         '../include/v8-version.h',
         '../include/v8.h',

src/value-serializer.cc

@@ -6,6 +6,7 @@
 
 #include <type_traits>
 
+#include "include/v8-value-serializer-version.h"
 #include "src/base/logging.h"
 #include "src/conversions.h"
 #include "src/factory.h"
@@ -30,6 +31,8 @@ namespace internal {
 // Version 13: host objects have an explicit tag (rather than handling all
 //             unknown tags)
 static const uint32_t kLatestVersion = 13;
+static_assert(kLatestVersion == v8::CurrentValueSerializerFormatVersion(),
+              "Exported format version must match latest version.");
 
 static const int kPretenureThreshold = 100 * KB;
 
@@ -154,11 +157,6 @@ enum class WasmEncodingTag : uint8_t {
 
 }  // namespace
 
-// static
-uint32_t ValueSerializer::GetCurrentDataFormatVersion() {
-  return kLatestVersion;
-}
-
 ValueSerializer::ValueSerializer(Isolate* isolate,
                                  v8::ValueSerializer::Delegate* delegate)
     : isolate_(isolate),

src/value-serializer.h

@@ -43,8 +43,6 @@ enum class SerializationTag : uint8_t;
  */
 class ValueSerializer {
  public:
-  static uint32_t GetCurrentDataFormatVersion();
-
   ValueSerializer(Isolate* isolate, v8::ValueSerializer::Delegate* delegate);
   ~ValueSerializer();