[snapshot] introduce SnapshotCreator API.

include/v8.h

 // Copyright 2012 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.
 
 /** \mainpage V8 API Reference Guide
  *
  * V8 is Google's open source JavaScript engine.
  *
  * This set of documents provides reference material generated from the
  * V8 header file, include/v8.h.
@@ skipping 6474 matching lines @@
    * warm-up script to trigger code compilation. The side effects are then
    * discarded. The resulting startup snapshot will include compiled code.
    * Returns { NULL, 0 } on failure.
    * The caller acquires ownership of the data array in the return value.
    * The argument startup blob is untouched.
    */
   static StartupData WarmUpSnapshotDataBlob(StartupData cold_startup_blob,
                                             const char* warmup_source);
 
   /**
+   * Helper class to create a snapshot data blob.
+   */
+  class SnapshotCreator {

[jochen (gone - plz use gerrit), 2016/06/08 13:06:48]

I'd not make this a subclass of V8 but a top-level class

[Yang, 2016/06/08 13:30:29]

Done.

+   public:
+    enum FunctionCodeHandling { CLEAR_FUNCTION_CODE, KEEP_FUNCTION_CODE };

[jochen (gone - plz use gerrit), 2016/06/08 13:06:48]

what about using an enum class { kClear, kKeep}

[Yang, 2016/06/08 13:30:29]

Done.

+
+    /**
+     * Create an enter an isolate, which is correctly set up for serialization.
+     * The isolate is either created from scratch or from an existing snapshot.
+     * The caller keeps ownership of the argument snapshot.
+     */
+    explicit SnapshotCreator(StartupData* existing_blob = nullptr);

[jochen (gone - plz use gerrit), 2016/06/08 13:06:48]

can you explain why the existing snapshot is needed?

[Yang, 2016/06/08 13:30:29]

As discussed, this is for creating warmed up snapshots.

+
+    ~SnapshotCreator();
+
+    /**
+     * \returns the isolate prepared by the snapshot creator.
+     */
+    Isolate* GetIsolate();
+
+    /**
+     * Add a context to be included in the snapshot blob.
+     */
+    void AddContext(Local<Context> context);
+
+    /**
+     * Created a snapshot data blob.
+     * \param function_code_handling whether to include compiled function code
+     *        in the snapshot.
+     * \returns { NULL, 0 } on failure, and a startup snapshot on success. The

[jochen (gone - plz use gerrit), 2016/06/08 13:06:48]

nullptr? 

[Yang, 2016/06/08 13:30:29]

Done.

+     *        caller acquires ownership of the data array in the return value.
+     */
+    StartupData CreateBlob(
+        FunctionCodeHandling function_code_handling = CLEAR_FUNCTION_CODE);

[jochen (gone - plz use gerrit), 2016/06/08 13:06:48]

I don't think the default arg is needed

[Yang, 2016/06/08 13:30:29]

Done.

+
+   private:
+    void* data_;
+  };

[jochen (gone - plz use gerrit), 2016/06/08 13:06:48]

do we have some DISALLOW_COPY_AND_ASSING in the API?

[Yang, 2016/06/08 13:30:29]

We don't have it as a macro, but override the copy constructor and = operator in
some places.

I could also use DISALLOW_COPY_AND_ASSIGN on the ArrayBufferAllocator member to
achieve the same effect...

+
+  /**
    * Adds a message listener.
    *
    * The same message listener can be added more than once and in that
    * case it will be called more than once for each message.
    *
    * If data is specified, it will be passed to the callback when it is called.
    * Otherwise, the exception object will be passed to the callback instead.
    */
   V8_INLINE static V8_DEPRECATED(
       "Use isolate version",
@@ skipping 2324 matching lines @@
  */
 
 
 }  // namespace v8
 
 
 #undef TYPE_CHECK
 
 
 #endif  // INCLUDE_V8_H_