JSONStream and tests

runtime/vm/json_stream.cc

Index: runtime/vm/json_stream.cc
diff --git a/runtime/vm/json_stream.cc b/runtime/vm/json_stream.cc
new file mode 100644
index 0000000000000000000000000000000000000000..59a8524f85fddd2d0f7dc264b9f6df301f80ef42
--- /dev/null
+++ b/runtime/vm/json_stream.cc
@@ -0,0 +1,126 @@
+// 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/json_stream.h"
+
+
+namespace dart {
+
+JSONStream::JSONStream(TextBuffer* buffer) {
+  ASSERT(buffer != NULL);
+  buffer_ = buffer;
+  open_objects_ = 0;

[Ivan Posva, 2013/07/01 23:18:14]

What is open_object_ used for?

[Cutch, 2013/07/01 23:33:55]

Sanity check for calls to OpenObject / CloseObject.

+}
+
+
+JSONStream::~JSONStream() {

[Ivan Posva, 2013/07/01 23:18:14]

Who is charged with freeing the TextBuffer?

[Cutch, 2013/07/01 23:33:55]

TextBuffer is a ValueObject so it is cleaned up when the stack unwinds.

+}
+
+
+void JSONStream::Clear() {
+  buffer_->Clear();
+  open_objects_ = 0;
+}
+

[Ivan Posva, 2013/07/01 23:18:14]

2 lines.

[Cutch, 2013/07/01 23:33:55]

Done.

+void JSONStream::OpenObject() {
+  open_objects_++;
+  buffer_->AddChar('{');
+}
+
+
+void JSONStream::CloseObject() {
+  ASSERT(open_objects_ > 0);
+  open_objects_--;
+  buffer_->AddChar('}');
+}
+
+
+void JSONStream::OpenArray() {
+  open_objects_++;
+  buffer_->AddChar('[');
+}
+
+
+void JSONStream::CloseArray() {
+  ASSERT(open_objects_ > 0);
+  open_objects_--;
+  buffer_->AddChar(']');
+}
+
+
+void JSONStream::PrintValueBool(bool b) {
+  PrintCommaIfNeeded();
+  buffer_->Printf("%s", b ? "true" : "false");

[Ivan Posva, 2013/07/01 23:18:14]

How about adding a private PrintBool(bool b) and call this from here and
PrintPropertyBool? This would make the decision as to when to check for
NeedsComma easier.

[Cutch, 2013/07/01 23:33:55]

Not sure what this has to do with PrintCommaIfNeeded, it needs to be called
before each value is printed.

+}
+
+
+void JSONStream::PrintValue(int i) {
+  PrintCommaIfNeeded();
+  buffer_->Printf("%d", i);
+}
+
+
+void JSONStream::PrintValue(double d) {
+  PrintCommaIfNeeded();
+  buffer_->Printf("%f", d);
+}
+
+
+void JSONStream::PrintValue(const char* s) {
+  PrintCommaIfNeeded();
+  buffer_->Printf("\"%s\"", s);
+}
+
+
+void JSONStream::PrintPropertyBool(const char* name, bool b) {
+  PrintPropertyName(name);
+  PrintValueBool(b);
+}
+
+
+void JSONStream::PrintProperty(const char* name, int i) {
+  PrintPropertyName(name);
+  PrintValue(i);
+}
+
+
+void JSONStream::PrintProperty(const char* name, double d) {
+  PrintPropertyName(name);
+  PrintValue(d);
+}
+
+
+void JSONStream::PrintProperty(const char* name, const char* s) {
+  PrintPropertyName(name);
+  PrintValue(s);
+}
+
+
+void JSONStream::PrintPropertyName(const char* name) {
+  ASSERT(name != NULL);
+  PrintCommaIfNeeded();
+  buffer_->Printf("\"%s\":", name);
+}
+
+
+void JSONStream::PrintCommaIfNeeded() {
+  if (NeedComma()) {
+    buffer_->AddChar(',');
+  }
+}
+
+
+bool JSONStream::NeedComma() {
+  const char* buffer = buffer_->buf();
+  intptr_t length = buffer_->length();
+  if (length == 0) {
+    return false;
+  }
+  char ch = buffer[length-1];
+  return ch != '[' && ch != '{' && ch != ':';
+}
+
+}  // namespace dart
+