Allow Observatory debugger to switch isolates.

runtime/vm/json_stream.cc

 // Copyright (c) 2013, 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 "platform/assert.h"
 
 #include "vm/dart_entry.h"
 #include "vm/debugger.h"
 #include "vm/json_stream.h"
 #include "vm/message.h"
@@ skipping 257 matching lines @@
 
 
 void JSONStream::PrintPropertyBool(const char* name, bool b) {
   PrintPropertyName(name);
   PrintValueBool(b);
 }
 
 
 void JSONStream::PrintProperty(const char* name, intptr_t i) {
   PrintPropertyName(name);
   PrintValue(i);

[Cutch, 2015/03/18 20:05:48]

Need JavaScript range ASSERT here too (for 64-bit architectures).

[turnidge, 2015/03/26 17:46:58]

Done.

 }
 
 
 void JSONStream::PrintProperty64(const char* name, int64_t i) {
+  // dart2js represents integers as double precision floats, which can
+  // represent anything in the range -2^53 ... 2^53.
+  ASSERT((-0x20000000000000LL <= i) && (i <= 0x20000000000000LL));

[Cutch, 2015/03/18 20:05:48]

How about:
#define MAX_JAVASCRIPT_INT 0x20000000000000LL
#define MIN_JAVASCRIPT_INT -MAX_JAVASCRIPT_INT

[turnidge, 2015/03/26 17:46:58]

Added IsJavascriptInt to utils.h.

   PrintPropertyName(name);
   PrintValue64(i);
 }
 
 
 void JSONStream::PrintProperty(const char* name, double d) {
   PrintPropertyName(name);
   PrintValue(d);
 }
 
@@ skipping 190 matching lines @@
   intptr_t len2 = OS::VSNPrint(p, len+1, format, args);
   va_end(args);
   ASSERT(len == len2);
   stream_->buffer_.AddChar('"');
   stream_->AddEscapedUTF8String(p);
   stream_->buffer_.AddChar('"');
   free(p);
 }
 
 }  // namespace dart