Support external startup data in V8.

src/snapshot-common.cc

 // Copyright 2006-2008 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.
 
 // The common functionality when building with or without snapshots.
 
 #include "v8.h"
 
 #include "api.h"
 #include "serialize.h"
 #include "snapshot.h"
 #include "platform.h"
 
 namespace v8 {
 namespace internal {
 
 
-static void ReserveSpaceForSnapshot(Deserializer* deserializer,
-                                    const char* file_name) {
-  int file_name_length = StrLength(file_name) + 10;
-  Vector<char> name = Vector<char>::New(file_name_length + 1);
-  OS::SNPrintF(name, "%s.size", file_name);
-  FILE* fp = OS::FOpen(name.start(), "r");
-  CHECK_NE(NULL, fp);
-  int new_size, pointer_size, data_size, code_size, map_size, cell_size,
-      property_cell_size;
-#ifdef _MSC_VER
-  // Avoid warning about unsafe fscanf from MSVC.
-  // Please note that this is only fine if %c and %s are not being used.
-#define fscanf fscanf_s
-#endif
-  CHECK_EQ(1, fscanf(fp, "new %d\n", &new_size));
-  CHECK_EQ(1, fscanf(fp, "pointer %d\n", &pointer_size));
-  CHECK_EQ(1, fscanf(fp, "data %d\n", &data_size));
-  CHECK_EQ(1, fscanf(fp, "code %d\n", &code_size));
-  CHECK_EQ(1, fscanf(fp, "map %d\n", &map_size));
-  CHECK_EQ(1, fscanf(fp, "cell %d\n", &cell_size));
-  CHECK_EQ(1, fscanf(fp, "property cell %d\n", &property_cell_size));
-#ifdef _MSC_VER
-#undef fscanf
-#endif
-  fclose(fp);
-  deserializer->set_reservation(NEW_SPACE, new_size);
-  deserializer->set_reservation(OLD_POINTER_SPACE, pointer_size);
-  deserializer->set_reservation(OLD_DATA_SPACE, data_size);
-  deserializer->set_reservation(CODE_SPACE, code_size);
-  deserializer->set_reservation(MAP_SPACE, map_size);
-  deserializer->set_reservation(CELL_SPACE, cell_size);
-  deserializer->set_reservation(PROPERTY_CELL_SPACE,
-                                property_cell_size);
-  name.Dispose();
-}
-
-
 void Snapshot::ReserveSpaceForLinkedInSnapshot(Deserializer* deserializer) {
   deserializer->set_reservation(NEW_SPACE, new_space_used_);
   deserializer->set_reservation(OLD_POINTER_SPACE, pointer_space_used_);
   deserializer->set_reservation(OLD_DATA_SPACE, data_space_used_);
   deserializer->set_reservation(CODE_SPACE, code_space_used_);
   deserializer->set_reservation(MAP_SPACE, map_space_used_);
   deserializer->set_reservation(CELL_SPACE, cell_space_used_);
   deserializer->set_reservation(PROPERTY_CELL_SPACE,
                                 property_cell_space_used_);
 }
 
 
-bool Snapshot::Initialize(const char* snapshot_file) {
-  if (snapshot_file) {
-    int len;
-    byte* str = ReadBytes(snapshot_file, &len);
-    if (!str) return false;
-    bool success;
-    {
-      SnapshotByteSource source(str, len);
-      Deserializer deserializer(&source);
-      ReserveSpaceForSnapshot(&deserializer, snapshot_file);
-      success = V8::Initialize(&deserializer);
-    }
-    DeleteArray(str);
-    return success;
-  } else if (size_ > 0) {
+bool Snapshot::Initialize() {
+  if (size_ > 0) {
     ElapsedTimer timer;
     if (FLAG_profile_deserialization) {
       timer.Start();
     }
     SnapshotByteSource source(raw_data_, raw_size_);
     Deserializer deserializer(&source);
     ReserveSpaceForLinkedInSnapshot(&deserializer);
     bool success = V8::Initialize(&deserializer);
     if (FLAG_profile_deserialization) {
       double ms = timer.Elapsed().InMillisecondsF();
       PrintF("[Snapshot loading and deserialization took %0.3f ms]\n", ms);
     }
     return success;
   }
   return false;
 }
 
 
 bool Snapshot::HaveASnapshotToStartFrom() {
   return size_ != 0;
 }
 
 
+bool Snapshot::IsEnabled() {

[Benedikt Meurer, 2014/05/27 04:09:59]

Nit: IsEnabled() should be marked as const.
Why do we need that function at all? Looks like it does the same as
HaveASnapshotToStartFrom()?

[vogelheim, 2014/05/27 15:20:23]

Removed IsEnabled; it's the exact same thing as HaveASnapshotToStartFrom.

It couldn't be const, though, since it's static:
https://code.google.com/p/chromium/codesearch#chromium/src/v8/src/snapshot.h&...

+  return size_ != 0;
+}
+
+
 Handle<Context> Snapshot::NewContextFromSnapshot(Isolate* isolate) {
   if (context_size_ == 0) {
     return Handle<Context>();
   }
   SnapshotByteSource source(context_raw_data_,
                             context_raw_size_);
   Deserializer deserializer(&source);
   Object* root;
   deserializer.set_reservation(NEW_SPACE, context_new_space_used_);
   deserializer.set_reservation(OLD_POINTER_SPACE, context_pointer_space_used_);
   deserializer.set_reservation(OLD_DATA_SPACE, context_data_space_used_);
   deserializer.set_reservation(CODE_SPACE, context_code_space_used_);
   deserializer.set_reservation(MAP_SPACE, context_map_space_used_);
   deserializer.set_reservation(CELL_SPACE, context_cell_space_used_);
   deserializer.set_reservation(PROPERTY_CELL_SPACE,
                                context_property_cell_space_used_);
   deserializer.DeserializePartial(isolate, &root);
   CHECK(root->IsContext());
   return Handle<Context>(Context::cast(root));
 }
 
+
+#ifdef V8_USE_EXTERNAL_STARTUP_DATA
+// Dummy implementations of Set*FromFile(..) APIs.
+//
+// These are meant for use with snapshot-external.cc. Should this file
+// be compiled with those options we just supply these dummy implementations
+// below. This happens when compiling the mksnapshot utility.
+void SetNativesFromFile(StartupData* data) { CHECK(false); }
+void SetSnapshotFromFile(StartupData* data) { CHECK(false); }
+#endif  // V8_USE_EXTERNAL_STARTUP_DATA
+
 } }  // namespace v8::internal