tools/profiler/JSStreamWriter.cpp

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 #include "JSStreamWriter.h"
   7
   8 #include "mozilla/ArrayUtils.h" // for ArrayLength
   9 #include "nsDataHashtable.h"
  10 #include "nsString.h"
  11 #include "nsTArray.h"
  12 #include "nsUTF8Utils.h"
  13
  14 #if _MSC_VER
  15  #define snprintf _snprintf
  16 #endif
  17
  18 #define ARRAY (void*)1
  19 #define OBJECT (void*)2
  20
  21 // Escape a UTF8 string to a stream. When an illegal encoding
  22 // is found it will insert "INVALID" and the function will return.
  23 static void EscapeToStream(std::ostream& stream, const char* str) {
  24   stream << "\"";
  25
  26   size_t len = strlen(str);
  27   const char* end = &str[len];
  28   while (str < end) {
  29     bool err;
  30     const char* utf8CharStart = str;
  31     uint32_t ucs4Char = UTF8CharEnumerator::NextChar(&str, end, &err);
  32
  33     if (err) {
  34       // Encoding error
  35       stream << "INVALID\"";
  36       return;
  37     }
  38
  39     // See http://www.ietf.org/rfc/rfc4627.txt?number=4627
  40     // characters that must be escaped: quotation mark,
  41     // reverse solidus, and the control characters
  42     // (U+0000 through U+001F).
  43     if (ucs4Char == '\"') {
  44       stream << "\\\"";
  45     } else if (ucs4Char == '\\') {
  46       stream << "\\\\";
  47     } else if (ucs4Char > 0xFF) {
  48       char16_t chr[2];
  49       ConvertUTF8toUTF16 encoder(chr);
  50       encoder.write(utf8CharStart, uint32_t(str-utf8CharStart));
  51       char escChar[13];
  52       snprintf(escChar, mozilla::ArrayLength(escChar), "\\u%04X\\u%04X", chr[0], chr[1]);
  53       stream << escChar;
  54     } else if (ucs4Char < 0x1F || ucs4Char > 0xFF) {
  55       char escChar[7];
  56       snprintf(escChar, mozilla::ArrayLength(escChar), "\\u%04X", ucs4Char);
  57       stream << escChar;
  58     } else {
  59       stream << char(ucs4Char);
  60     }
  61   }
  62   stream << "\"";
  63 }
  64
  65 JSStreamWriter::JSStreamWriter(std::ostream& aStream)
  66   : mStream(aStream)
  67   , mNeedsComma(false)
  68   , mNeedsName(false)
  69 { }
  70
  71 JSStreamWriter::~JSStreamWriter()
  72 {
  73   MOZ_ASSERT(mStack.GetSize() == 0);
  74 }
  75
  76 void
  77 JSStreamWriter::BeginObject()
  78 {
  79   MOZ_ASSERT(!mNeedsName);
  80   if (mNeedsComma && mStack.Peek() == ARRAY) {
  81     mStream << ",";
  82   }
  83   mStream << "{";
  84   mNeedsComma = false;
  85   mNeedsName = true;
  86   mStack.Push(OBJECT);
  87 }
  88
  89 void
  90 JSStreamWriter::EndObject()
  91 {
  92   MOZ_ASSERT(mStack.Peek() == OBJECT);
  93   mStream << "}";
  94   mNeedsComma = true;
  95   mNeedsName = false;
  96   mStack.Pop();
  97   if (mStack.GetSize() > 0 && mStack.Peek() == OBJECT) {
  98     mNeedsName = true;
  99   }
 100 }
 101
 102 void
 103 JSStreamWriter::BeginArray()
 104 {
 105   MOZ_ASSERT(!mNeedsName);
 106   if (mNeedsComma && mStack.Peek() == ARRAY) {
 107     mStream << ",";
 108   }
 109   mStream << "[";
 110   mNeedsComma = false;
 111   mStack.Push(ARRAY);
 112 }
 113
 114 void
 115 JSStreamWriter::EndArray()
 116 {
 117   MOZ_ASSERT(!mNeedsName);
 118   MOZ_ASSERT(mStack.Peek() == ARRAY);
 119   mStream << "]";
 120   mNeedsComma = true;
 121   mStack.Pop();
 122   if (mStack.GetSize() > 0 && mStack.Peek() == OBJECT) {
 123     mNeedsName = true;
 124   }
 125 }
 126
 127 void
 128 JSStreamWriter::Name(const char *aName)
 129 {
 130   MOZ_ASSERT(mNeedsName);
 131   if (mNeedsComma && mStack.Peek() == OBJECT) {
 132     mStream << ",";
 133   }
 134   EscapeToStream(mStream, aName);
 135   mStream << ":";
 136   mNeedsName = false;
 137 }
 138
 139 void
 140 JSStreamWriter::Value(int aValue)
 141 {
 142   MOZ_ASSERT(!mNeedsName);
 143   if (mNeedsComma && mStack.Peek() == ARRAY) {
 144     mStream << ",";
 145   }
 146   mStream << aValue;
 147   mNeedsComma = true;
 148   if (mStack.Peek() == OBJECT) {
 149     mNeedsName = true;
 150   }
 151 }
 152
 153 void
 154 JSStreamWriter::Value(double aValue)
 155 {
 156   MOZ_ASSERT(!mNeedsName);
 157   if (mNeedsComma && mStack.Peek() == ARRAY) {
 158     mStream << ",";
 159   }
 160   mStream.precision(18);
 161   mStream << aValue;
 162   mNeedsComma = true;
 163   if (mStack.Peek() == OBJECT) {
 164     mNeedsName = true;
 165   }
 166 }
 167
 168 void
 169 JSStreamWriter::Value(const char *aValue)
 170 {
 171   MOZ_ASSERT(!mNeedsName);
 172   if (mNeedsComma && mStack.Peek() == ARRAY) {
 173     mStream << ",";
 174   }
 175   EscapeToStream(mStream, aValue);
 176   mNeedsComma = true;
 177   if (mStack.Peek() == OBJECT) {
 178     mNeedsName = true;
 179   }
 180 }