Allow printf-style arguments for Dart_Error and Api::Error.

runtime/vm/dart_api_impl.cc

 // Copyright (c) 2011, 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_api.h"
 
 #include "vm/bigint_operations.h"
 #include "vm/class_finalizer.h"
 #include "vm/compiler.h"
 #include "vm/dart.h"
@@ skipping 49 matching lines @@
   failure ^= obj.raw();
   const String& message = String::Handle(failure.message());
   const char* msg = message.ToCString();
   intptr_t len = strlen(msg) + 1;
   char* msg_copy = reinterpret_cast<char*>(Api::Allocate(len));
   OS::SNPrint(msg_copy, len, "%s", msg);
   return msg_copy;
 }
 
 
-DART_EXPORT Dart_Handle Dart_Error(const char* error) {
-  return Api::Error(error);
+DART_EXPORT Dart_Handle Dart_Error(const char* format, ...) {
+  va_list args;
+  va_start(args, format);
+  Dart_Handle error = Api::VError(format, args);
+  va_end(args);
+  return error;
 }
 
 
 // TODO(iposva): This is a placeholder for the eventual external Dart API.
 DART_EXPORT bool Dart_Initialize(int argc,
                                  char** argv,
                                  Dart_IsolateInitCallback callback) {
   return Dart::InitOnce(argc, argv, callback);
 }
 
@@ skipping 438 matching lines @@
     return Api::Error("Invalid class name specified");
   }
   const Library& lib = Library::CheckedHandle(Api::UnwrapHandle(library));
   if (lib.IsNull()) {
     return Api::Error("Invalid parameter, Unknown library specified");
   }
   String& cls_name = String::Handle();
   cls_name ^= param.raw();
   const Class& cls = Class::Handle(lib.LookupClass(cls_name));
   if (cls.IsNull()) {
-    return Api::Error("Specified class does not exist");
+    const String& lib_name = String::Handle(lib.name());
+    return Api::Error("Class '%s' not found in library '%s'.",
+                      cls_name.ToCString(), lib_name.ToCString());
   }
   return Api::NewLocalHandle(cls);
 }
 
 
 // TODO(iposva): This call actually implements IsInstanceOfClass.
 // Do we also need a real Dart_IsInstanceOf, which should take an instance
 // rather than an object and a type rather than a class?
 DART_EXPORT Dart_Handle Dart_IsInstanceOf(Dart_Handle object,
                                           Dart_Handle clazz,
@@ skipping 1460 matching lines @@
 Dart_Handle Api::Success() {
   Isolate* isolate = Isolate::Current();
   ASSERT(isolate != NULL);
   ApiState* state = isolate->api_state();
   ASSERT(state != NULL);
   PersistentHandle* true_handle = state->True();
   return reinterpret_cast<Dart_Handle>(true_handle);
 }
 
 
-Dart_Handle Api::Error(const char* text) {
+Dart_Handle Api::VError(const char* format, va_list args) {
   Zone zone;  // Setup a VM zone as we are creating some handles.
   HandleScope scope;  // Setup a VM handle scope.
-  const String& message = String::Handle(String::New(text));
+
+  intptr_t len = OS::VSNPrint(NULL, 0, format, args);
+  char* buffer = reinterpret_cast<char*>(zone.Allocate(len+1));
+  OS::VSNPrint(buffer, len+1, format, args);

[Anton Muhin, 2011/11/08 08:32:18]

nit: space around + ?

[turnidge, 2011/11/08 19:02:02]

Done.

+
+  const String& message = String::Handle(String::New(buffer));
   const Object& obj = Object::Handle(ApiFailure::New(message));
   return Api::NewLocalHandle(obj);
 }
 
 
+Dart_Handle Api::Error(const char* format, ...) {

[Anton Muhin, 2011/11/08 08:32:18]

looks pretty much like Dart_Error.  Do we need both?

[turnidge, 2011/11/08 19:02:02]

I am providing Dart_Error for external developers.  The "Api" apis are a bit
more extensive and for internal use.  We may be able to get rid of one in the
future -- perhaps by moving more of the "Api" apis to "Dart_" and always using
those.

Will keep this in mind for later.

+  va_list args;
+  va_start(args, format);
+  Dart_Handle error = Api::VError(format, args);
+  va_end(args);
+  return error;
+}
+
+
 Dart_Handle Api::Null() {
   Isolate* isolate = Isolate::Current();
   ASSERT(isolate != NULL);
   ApiState* state = isolate->api_state();
   ASSERT(state != NULL);
   PersistentHandle* null_handle = state->Null();
   return reinterpret_cast<Dart_Handle>(null_handle);
 }
 
 
@@ skipping 33 matching lines @@
   ASSERT(isolate != NULL);
   ApiState* state = isolate->api_state();
   ASSERT(state != NULL);
   ApiLocalScope* scope = state->top_scope();
   ASSERT(scope != NULL);
   return scope->zone().Reallocate(ptr, old_size, new_size);
 }
 
 
 }  // namespace dart