VM: Const-correctness fixes.

runtime/lib/isolate.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "include/dart_native_api.h"
 #include "platform/assert.h"
 #include "vm/bootstrap_natives.h"
 #include "vm/class_finalizer.h"
 #include "vm/dart.h"
 #include "vm/dart_api_impl.h"
@@ skipping 239 matching lines @@
       return Object::null();
     }
   }
   const String& msg = String::Handle(String::New(
       "Isolate.spawn expects to be passed a static or top-level function"));
   Exceptions::ThrowArgumentError(msg);
   return Object::null();
 }
 
 
-static char* String2UTF8(const String& str) {
+static const char* String2UTF8(const String& str) {
   intptr_t len = Utf8::Length(str);
   char* result = new char[len + 1];
   str.ToUTF8(reinterpret_cast<uint8_t*>(result), len);
   result[len] = 0;
 
   return result;
 }
 
 
-static char* CanonicalizeUri(Thread* thread,
-                             const Library& library,
-                             const String& uri,
-                             char** error) {
-  char* result = NULL;
+static const char* CanonicalizeUri(Thread* thread,
+                                   const Library& library,
+                                   const String& uri,
+                                   char** error) {
+  const char* result = NULL;
   Zone* zone = thread->zone();
   Isolate* isolate = thread->isolate();
   Dart_LibraryTagHandler handler = isolate->library_tag_handler();
   if (handler != NULL) {
     Dart_EnterScope();
     Dart_Handle handle = handler(Dart_kCanonicalizeUrl,
                                  Api::NewHandle(thread, library.raw()),
                                  Api::NewHandle(thread, uri.raw()));
     const Object& obj = Object::Handle(Api::UnwrapHandle(handle));
     if (obj.IsString()) {
@@ skipping 42 matching lines @@
     args.SetAt(0, String::Handle(String::New(
         "Isolate.spawnUri not supported under precompilation")));
     Exceptions::ThrowByType(Exceptions::kUnsupported, args);
     UNREACHABLE();
   }
 
   // Canonicalize the uri with respect to the current isolate.
   const Library& root_lib =
       Library::Handle(isolate->object_store()->root_library());
   char* error = NULL;
-  char* canonical_uri = CanonicalizeUri(thread, root_lib, uri, &error);
+  const char* canonical_uri = CanonicalizeUri(thread, root_lib, uri, &error);
   if (canonical_uri == NULL) {
     const String& msg = String::Handle(String::New(error));
     ThrowIsolateSpawnException(msg);
   }
 
-  char* utf8_package_root =
+  const char* utf8_package_root =
       package_root.IsNull() ? NULL : String2UTF8(package_root);
 
-  char** utf8_package_map = NULL;
+  const char** utf8_package_map = NULL;
   if (!packages.IsNull()) {
     intptr_t len = packages.Length();
-    utf8_package_map = new char*[len + 1];
+    utf8_package_map = new const char*[len + 1];
 
     Object& entry = Object::Handle();
     for (intptr_t i = 0; i < len; i++) {
       entry = packages.At(i);
       if (!entry.IsString()) {
         const String& msg = String::Handle(String::NewFormatted(
             "Bad value in package map: %s", entry.ToCString()));
         ThrowIsolateSpawnException(msg);
       }
       utf8_package_map[i] = String2UTF8(String::Cast(entry));
     }
     // NULL terminated array.
     utf8_package_map[len] = NULL;
   }
 
   bool fatal_errors = fatalErrors.IsNull() ? true : fatalErrors.value();
   Dart_Port on_exit_port = onExit.IsNull() ? ILLEGAL_PORT : onExit.Id();
   Dart_Port on_error_port = onError.IsNull() ? ILLEGAL_PORT : onError.Id();
 
   IsolateSpawnState* state =
       new IsolateSpawnState(
           port.Id(),
           isolate->init_callback_data(),
           canonical_uri,
           utf8_package_root,
-          const_cast<const char**>(utf8_package_map),
+          utf8_package_map,
           args,
           message,
           paused.value(),
           fatal_errors,
           on_exit_port,
           on_error_port);
 
   // If we were passed a value then override the default flags state for
   // checked mode.
   if (!checked.IsNull()) {
@@ skipping 38 matching lines @@
   MessageWriter writer(&data, &allocator, false);
   writer.WriteMessage(msg);
 
   PortMap::PostMessage(new Message(port.Id(),
                                    data, writer.BytesWritten(),
                                    Message::kOOBPriority));
   return Object::null();
 }
 
 }  // namespace dart