Fix cctest + unittest to work with an external snapshot.

src/startup-data-util.cc

+// Copyright 2015 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/startup-data-util.h"
+
+#include <stdlib.h>
+#include <string.h>
+
+#include "src/base/logging.h"
+
+
+namespace v8 {
+
+#ifdef V8_USE_EXTERNAL_STARTUP_DATA
+
+StartupDataHandler::StartupDataHandler(const char* exec_path,
+                                       const char* natives_blob,
+                                       const char* snapshot_blob) {
+  // If we have (at least one) explicitly given blob, use those.
+  // If not, use the default blob locations next to the d8 binary.
+  if (natives_blob || snapshot_blob) {
+    LoadFromFiles(natives_blob, snapshot_blob);
+  } else {
+    char* natives;
+    char* snapshot;
+    LoadFromFiles(RelativePath(&natives, exec_path, "natives_blob.bin"),
+                  RelativePath(&snapshot, exec_path, "snapshot_blob.bin"));
+
+    free(natives);
+    free(snapshot);
+  }
+}
+
+
+StartupDataHandler::~StartupDataHandler() {
+  delete[] natives_.data;
+  delete[] snapshot_.data;
+}
+
+
+char* StartupDataHandler::RelativePath(char** buffer, const char* exec_path,
+                                       const char* name) {
+  DCHECK(exec_path);
+  const char* last_slash = strrchr(exec_path, '/');
+  if (last_slash) {
+    int after_slash = last_slash - exec_path + 1;
+    int name_length = static_cast<int>(strlen(name));
+    *buffer = reinterpret_cast<char*>(calloc(after_slash + name_length + 1, 1));
+    strncpy(*buffer, exec_path, after_slash);
+    strncat(*buffer, name, name_length);
+  } else {
+    *buffer = strdup(name);
+  }
+  return *buffer;
+}
+
+
+void StartupDataHandler::LoadFromFiles(const char* natives_blob,
+                                       const char* snapshot_blob) {
+  Load(natives_blob, &natives_, v8::V8::SetNativesDataBlob);
+  Load(snapshot_blob, &snapshot_, v8::V8::SetSnapshotDataBlob);
+}
+
+
+void StartupDataHandler::Load(const char* blob_file,
+                              v8::StartupData* startup_data,
+                              void (*setter_fn)(v8::StartupData*)) {
+  startup_data->data = NULL;
+  startup_data->raw_size = 0;
+
+  if (!blob_file) return;
+
+  FILE* file = fopen(blob_file, "rb");
+  if (!file) return;
+
+  fseek(file, 0, SEEK_END);
+  startup_data->raw_size = ftell(file);
+  rewind(file);
+
+  startup_data->data = new char[startup_data->raw_size];
+  int read_size = static_cast<int>(fread(const_cast<char*>(startup_data->data),
+                                         1, startup_data->raw_size, file));
+  fclose(file);
+
+  if (startup_data->raw_size == read_size) (*setter_fn)(startup_data);
+}
+
+#endif  // V8_USE_EXTERNAL_STARTUP_DATA
+
+}  // namespace v8