diff -r 000000000000 -r 6474c204b198 tools/profiler/JSStreamWriter.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tools/profiler/JSStreamWriter.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,180 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "JSStreamWriter.h"
+
+#include "mozilla/ArrayUtils.h" // for ArrayLength
+#include "nsDataHashtable.h"
+#include "nsString.h"
+#include "nsTArray.h"
+#include "nsUTF8Utils.h"
+
+#if _MSC_VER
+ #define snprintf _snprintf
+#endif
+
+#define ARRAY (void*)1
+#define OBJECT (void*)2
+
+// Escape a UTF8 string to a stream. When an illegal encoding
+// is found it will insert "INVALID" and the function will return.
+static void EscapeToStream(std::ostream& stream, const char* str) {
+  stream << "\"";
+
+  size_t len = strlen(str);
+  const char* end = &str[len];
+  while (str < end) {
+    bool err;
+    const char* utf8CharStart = str;
+    uint32_t ucs4Char = UTF8CharEnumerator::NextChar(&str, end, &err);
+
+    if (err) {
+      // Encoding error
+      stream << "INVALID\"";
+      return;
+    }
+
+    // See http://www.ietf.org/rfc/rfc4627.txt?number=4627
+    // characters that must be escaped: quotation mark,
+    // reverse solidus, and the control characters
+    // (U+0000 through U+001F).
+    if (ucs4Char == '\"') {
+      stream << "\\\"";
+    } else if (ucs4Char == '\\') {
+      stream << "\\\\";
+    } else if (ucs4Char > 0xFF) {
+      char16_t chr[2];
+      ConvertUTF8toUTF16 encoder(chr);
+      encoder.write(utf8CharStart, uint32_t(str-utf8CharStart));
+      char escChar[13];
+      snprintf(escChar, mozilla::ArrayLength(escChar), "\\u%04X\\u%04X", chr[0], chr[1]);
+      stream << escChar;
+    } else if (ucs4Char < 0x1F || ucs4Char > 0xFF) {
+      char escChar[7];
+      snprintf(escChar, mozilla::ArrayLength(escChar), "\\u%04X", ucs4Char);
+      stream << escChar;
+    } else {
+      stream << char(ucs4Char);
+    }
+  }
+  stream << "\"";
+}
+
+JSStreamWriter::JSStreamWriter(std::ostream& aStream)
+  : mStream(aStream)
+  , mNeedsComma(false)
+  , mNeedsName(false)
+{ }
+
+JSStreamWriter::~JSStreamWriter()
+{
+  MOZ_ASSERT(mStack.GetSize() == 0);
+}
+
+void
+JSStreamWriter::BeginObject()
+{
+  MOZ_ASSERT(!mNeedsName);
+  if (mNeedsComma && mStack.Peek() == ARRAY) {
+    mStream << ",";
+  }
+  mStream << "{";
+  mNeedsComma = false;
+  mNeedsName = true;
+  mStack.Push(OBJECT);
+}
+
+void
+JSStreamWriter::EndObject()
+{
+  MOZ_ASSERT(mStack.Peek() == OBJECT);
+  mStream << "}";
+  mNeedsComma = true;
+  mNeedsName = false;
+  mStack.Pop();
+  if (mStack.GetSize() > 0 && mStack.Peek() == OBJECT) {
+    mNeedsName = true;
+  }
+}
+
+void
+JSStreamWriter::BeginArray()
+{
+  MOZ_ASSERT(!mNeedsName);
+  if (mNeedsComma && mStack.Peek() == ARRAY) {
+    mStream << ",";
+  }
+  mStream << "[";
+  mNeedsComma = false;
+  mStack.Push(ARRAY);
+}
+
+void
+JSStreamWriter::EndArray()
+{
+  MOZ_ASSERT(!mNeedsName);
+  MOZ_ASSERT(mStack.Peek() == ARRAY);
+  mStream << "]";
+  mNeedsComma = true;
+  mStack.Pop();
+  if (mStack.GetSize() > 0 && mStack.Peek() == OBJECT) {
+    mNeedsName = true;
+  }
+}
+
+void
+JSStreamWriter::Name(const char *aName)
+{
+  MOZ_ASSERT(mNeedsName);
+  if (mNeedsComma && mStack.Peek() == OBJECT) {
+    mStream << ",";
+  }
+  EscapeToStream(mStream, aName);
+  mStream << ":";
+  mNeedsName = false;
+}
+
+void
+JSStreamWriter::Value(int aValue)
+{
+  MOZ_ASSERT(!mNeedsName);
+  if (mNeedsComma && mStack.Peek() == ARRAY) {
+    mStream << ",";
+  }
+  mStream << aValue;
+  mNeedsComma = true;
+  if (mStack.Peek() == OBJECT) {
+    mNeedsName = true;
+  }
+}
+
+void
+JSStreamWriter::Value(double aValue)
+{
+  MOZ_ASSERT(!mNeedsName);
+  if (mNeedsComma && mStack.Peek() == ARRAY) {
+    mStream << ",";
+  }
+  mStream.precision(18);
+  mStream << aValue;
+  mNeedsComma = true;
+  if (mStack.Peek() == OBJECT) {
+    mNeedsName = true;
+  }
+}
+
+void
+JSStreamWriter::Value(const char *aValue)
+{
+  MOZ_ASSERT(!mNeedsName);
+  if (mNeedsComma && mStack.Peek() == ARRAY) {
+    mStream << ",";
+  }
+  EscapeToStream(mStream, aValue);
+  mNeedsComma = true;
+  if (mStack.Peek() == OBJECT) {
+    mNeedsName = true;
+  }
+}