Support external startup data in V8. (retry)

src/natives-external.cc

Index: src/natives-external.cc
diff --git a/src/natives-external.cc b/src/natives-external.cc
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+// Copyright 2014 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.
+
+#include "src/natives.h"
+
+#include "src/checks.h"
+#include "src/list.h"
+#include "src/list-inl.h"
+#include "src/snapshot-source-sink.h"
+#include "src/vector.h"
+
+namespace v8 {
+namespace internal {
+
+
+/**
+ * NativesStore stores the 'native' (builtin) JS libraries.
+ *
+ * NativesStore needs to be initialized before using V8, usually by the
+ * embedder calling v8::SetNativesDataBlob, which calls SetNativesFromFile
+ * below.
+ */
+class NativesStore {
+ public:
+  ~NativesStore() {}
+
+  int GetBuiltinsCount() { return native_names_.length(); }
+  int GetDebuggerCount() { return debugger_count_; }
+  Vector<const char> GetScriptName(int index) { return native_names_[index]; }
+  Vector<const char> GetRawScriptSource(int index) {
+    return native_source_[index];
+  }
+
+  int GetIndex(const char* name) {
+    for (int i = 0; i < native_names_.length(); ++i) {
+      if (strcmp(name, native_names_[i].start()) == 0) {
+        return i;
+      }
+    }
+    ASSERT(false);
+    return -1;
+  }
+
+  int GetRawScriptsSize() {
+    ASSERT(false);  // Used for compression. Doesn't really make sense here.
+    return 0;
+  }
+
+  Vector<const byte> GetScriptsSource() {
+    ASSERT(false);  // Used for compression. Doesn't really make sense here.
+    return Vector<const byte>();
+  }
+
+  static NativesStore* MakeFromScriptsSource(SnapshotByteSource* source) {
+    NativesStore* store = new NativesStore;
+
+    // We expect the libraries in the following format:
+    //   int: # of debugger sources.
+    //   2N blobs: N pairs of source name + actual source.
+    //   then, repeat for non-debugger sources.
+    int debugger_count = source->GetInt();
+    for (int i = 0; i < debugger_count; ++i)
+      store->ReadNameAndContentPair(source);
+    int library_count = source->GetInt();
+    for (int i = 0; i < library_count; ++i)
+      store->ReadNameAndContentPair(source);
+
+    store->debugger_count_ = debugger_count;
+    return store;
+  }
+
+ private:
+  NativesStore() : debugger_count_(0) {}
+
+  bool ReadNameAndContentPair(SnapshotByteSource* bytes) {
+    const byte* name;
+    int name_length;
+    const byte* source;
+    int source_length;
+    bool success = bytes->GetBlob(&name, &name_length) &&
+                   bytes->GetBlob(&source, &source_length);
+    if (success) {
+      Vector<const char> name_vector(
+          reinterpret_cast<const char*>(name), name_length);
+      Vector<const char> source_vector(
+          reinterpret_cast<const char*>(source), source_length);
+      native_names_.Add(name_vector);
+      native_source_.Add(source_vector);
+    }
+    return success;
+  }
+
+  List<Vector<const char> > native_names_;
+  List<Vector<const char> > native_source_;
+  int debugger_count_;
+
+  DISALLOW_COPY_AND_ASSIGN(NativesStore);
+};
+
+
+template<NativeType type>
+class NativesHolder {
+ public:
+  static NativesStore* get() {
+    ASSERT(holder_);
+    return holder_;
+  }
+  static void set(NativesStore* store) {
+    ASSERT(store);
+    holder_ = store;
+  }
+
+ private:
+  static NativesStore* holder_;
+};
+
+template<NativeType type>
+NativesStore* NativesHolder<type>::holder_ = NULL;
+
+
+/**
+ * Read the Natives (library sources) blob, as generated by js2c + the build
+ * system.
+ */
+void SetNativesFromFile(StartupData* natives_blob) {
+  ASSERT(natives_blob);
+  ASSERT(natives_blob->data);
+  ASSERT(natives_blob->raw_size > 0);
+
+  SnapshotByteSource bytes(
+      reinterpret_cast<const byte*>(natives_blob->data),
+      natives_blob->raw_size);
+  NativesHolder<CORE>::set(NativesStore::MakeFromScriptsSource(&bytes));
+  NativesHolder<EXPERIMENTAL>::set(NativesStore::MakeFromScriptsSource(&bytes));
+  ASSERT(!bytes.HasMore());
+}
+
+
+// Implement NativesCollection<T> bsaed on NativesHolder + NativesStore.
+//
+// (The callers expect a purely static interface, since this is how the
+//  natives are usually compiled in. Since we implement them based on
+//  runtime content, we have to implement this indirection to offer
+//  a static interface.)
+template<NativeType type>
+int NativesCollection<type>::GetBuiltinsCount() {
+  return NativesHolder<type>::get()->GetBuiltinsCount();
+}
+
+template<NativeType type>
+int NativesCollection<type>::GetDebuggerCount() {
+  return NativesHolder<type>::get()->GetDebuggerCount();
+}
+
+template<NativeType type>
+int NativesCollection<type>::GetIndex(const char* name) {
+  return NativesHolder<type>::get()->GetIndex(name);
+}
+
+template<NativeType type>
+int NativesCollection<type>::GetRawScriptsSize() {
+  return NativesHolder<type>::get()->GetRawScriptsSize();
+}
+
+template<NativeType type>
+Vector<const char> NativesCollection<type>::GetRawScriptSource(int index) {
+  return NativesHolder<type>::get()->GetRawScriptSource(index);
+}
+
+template<NativeType type>
+Vector<const char> NativesCollection<type>::GetScriptName(int index) {
+  return NativesHolder<type>::get()->GetScriptName(index);
+}
+
+template<NativeType type>
+Vector<const byte> NativesCollection<type>::GetScriptsSource() {
+  return NativesHolder<type>::get()->GetScriptsSource();
+}
+
+template<NativeType type>
+void NativesCollection<type>::SetRawScriptsSource(
+    Vector<const char> raw_source) {
+  CHECK(false);  // Use SetNativesFromFile for this implementation.
+}
+
+
+// The compiler can't 'see' all uses of the static methods and hence
+// my chose to elide them. This we'll explicitly instantiate these.
+template class NativesCollection<CORE>;
+template class NativesCollection<EXPERIMENTAL>;
+template class NativesCollection<D8>;
+template class NativesCollection<TEST>;
+
+}  // namespace v8::internal
+}  // namespace v8