Dart: Adds a program to create snapshots of Mojo apps.

mojo/dart/dart_snapshotter/vm.cc

+// Copyright 2015 The Chromium 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 "mojo/dart/dart_snapshotter/vm.h"
+
+#include "base/logging.h"
+#include "mojo/dart/dart_snapshotter/loader.h"
+#include "tonic/dart_error.h"
+#include "tonic/dart_state.h"
+
+namespace mojo {
+namespace dart {
+extern const uint8_t* vm_isolate_snapshot_buffer;
+extern const uint8_t* isolate_snapshot_buffer;
+}
+}
+
+static const char* kDartArgs[] = {
+    "--enable_mirrors=false",
+};
+
+void InitDartVM() {
+  CHECK(Dart_SetVMFlags(arraysize(kDartArgs), kDartArgs));
+  CHECK(Dart_Initialize(mojo::dart::vm_isolate_snapshot_buffer, nullptr,
+                        nullptr, nullptr, nullptr, nullptr, nullptr, nullptr,
+                        nullptr, nullptr));
+}
+
+Dart_Isolate CreateDartIsolate() {
+  CHECK(mojo::dart::isolate_snapshot_buffer);
+  char* error = nullptr;
+  Dart_Isolate isolate = Dart_CreateIsolate("dart:snapshot", "main",

[Cutch, 2015/08/11 14:18:06]

Does this "dart:" url make it into the program that loads the snapshot? Should
we use a different url just in case?

[zra, 2015/08/11 17:03:21]

This string is only used for debug messages, and doesn't make it into the
snapshot. I believe someone would only see this when trying to snapshot a script
with a syntax error, but the dart_pkg rule will fail in the analysis step before
attempting to make a snapshot, so this will never be visible.

+                                            mojo::dart::isolate_snapshot_buffer,
+                                            nullptr, nullptr, &error);
+
+  CHECK(isolate) << error;
+  CHECK(!tonic::LogIfError(Dart_SetLibraryTagHandler(HandleLibraryTag)));
+
+  Dart_ExitIsolate();
+  return isolate;
+}