Add DART_CHECKVALID

runtime/include/dart_api.h

Index: runtime/include/dart_api.h
===================================================================
--- runtime/include/dart_api.h	(revision 778)
+++ runtime/include/dart_api.h	(working copy)
@@ -79,13 +79,29 @@
 
 // TODO(iposva): This is a placeholder for the eventual external Dart API.
 
-// Return value handling after a Dart API call.
-DART_EXPORT bool Dart_IsValid(const Dart_Handle& result);
+// Returns true if 'handle' is valid and false if invalid.
+DART_EXPORT bool Dart_IsValid(const Dart_Handle& handle);
 
-DART_EXPORT const char* Dart_GetError(const Dart_Handle& result);
-DART_EXPORT Dart_Handle Dart_Error(const char* value);
+// Internal routine used for reporting bad handles.
+DART_EXPORT void _Dart_ReportInvalidHandle(bool fatal,
+                                           const char* file,
+                                           int line,
+                                           const char* handle_string,
+                                           const char* error);

[siva, 2011/10/27 21:15:54]

I am assuming you want the external users of this API
to also use the DART_CHECKVALID macro? In that case this
would not be an internal routine right.
Also external users may want to control whether the process aborts or does
something else through the macro.

[turnidge, 2011/10/27 21:55:20]

I don't want external users to call _Dart_ReportInvalidHandle directly.  That's
what I mean by internal -- is that the wrong meaning?

I don't want to give external users a non-fatal version.  If they had that, it
would mainly just spam their stderr but not do anything useful for them.  I have
dropped the "fatal" parameter.

 
+// Aborts the process if 'handle' is invalid.
+#define DART_CHECKVALID(handle)                                         \

[turnidge, 2011/10/27 21:55:20]

Which do you like better... DART_CHECKVALID or DART_CHECK_VALID.  I've decided
to go with the latter.

+  if (!Dart_IsValid((handle))) {                                        \
+    _Dart_ReportInvalidHandle(true, __FILE__, __LINE__,                 \
+                              #handle, Dart_GetError(handle));          \
+}

[siva, 2011/10/27 21:15:54]

Not sure what the style should be here, indented with if or over here? We have
been following indent with if.

[turnidge, 2011/10/27 21:55:20]

Fixed.

 
+// Gets the error message associated with an invalid handle.
+DART_EXPORT const char* Dart_GetError(const Dart_Handle& handle);
+
+// Produces an invalid handle with an associated error message
+DART_EXPORT Dart_Handle Dart_Error(const char* error);
+
 // Initialize the VM with commmand line flags.
 DART_EXPORT bool Dart_Initialize(int argc, char** argv,
                                  Dart_IsolateInitCallback callback);