[inspector] Initial import of v8_inspector.

src/inspector/String16.cpp

Index: src/inspector/String16.cpp
diff --git a/src/inspector/String16.cpp b/src/inspector/String16.cpp
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+// Copyright 2016 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "src/inspector/String16.h"
+
+#include "src/inspector/ProtocolPlatform.h"
+
+#include <algorithm>
+#include <cctype>
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
+#include <locale>
+#include <string>
+
+namespace v8_inspector {
+
+namespace {
+
+bool isASCII(UChar c) { return !(c & ~0x7F); }
+
+bool isSpaceOrNewLine(UChar c) {
+  return isASCII(c) && c <= ' ' && (c == ' ' || (c <= 0xD && c >= 0x9));
+}
+
+int charactersToInteger(const UChar* characters, size_t length,
+                        bool* ok = nullptr) {
+  std::vector<char> buffer;
+  buffer.reserve(length + 1);
+  for (size_t i = 0; i < length; ++i) {
+    if (!isASCII(characters[i])) {
+      if (ok) *ok = false;
+      return 0;
+    }
+    buffer.push_back(static_cast<char>(characters[i]));
+  }
+  buffer.push_back('\0');
+
+  char* endptr;
+  int result = std::strtol(buffer.data(), &endptr, 10);
+  if (ok) *ok = !(*endptr);
+  return result;
+}
+
+const UChar replacementCharacter = 0xFFFD;
+using UChar32 = uint32_t;
+
+inline int inlineUTF8SequenceLengthNonASCII(char b0) {
+  if ((b0 & 0xC0) != 0xC0) return 0;
+  if ((b0 & 0xE0) == 0xC0) return 2;
+  if ((b0 & 0xF0) == 0xE0) return 3;
+  if ((b0 & 0xF8) == 0xF0) return 4;
+  return 0;
+}
+
+inline int inlineUTF8SequenceLength(char b0) {
+  return isASCII(b0) ? 1 : inlineUTF8SequenceLengthNonASCII(b0);
+}
+
+// Once the bits are split out into bytes of UTF-8, this is a mask OR-ed
+// into the first byte, depending on how many bytes follow.  There are
+// as many entries in this table as there are UTF-8 sequence types.
+// (I.e., one byte sequence, two byte... etc.). Remember that sequences
+// for *legal* UTF-8 will be 4 or fewer bytes total.
+static const unsigned char firstByteMark[7] = {0x00, 0x00, 0xC0, 0xE0,
+                                               0xF0, 0xF8, 0xFC};
+
+typedef enum {
+  conversionOK,     // conversion successful
+  sourceExhausted,  // partial character in source, but hit end
+  targetExhausted,  // insuff. room in target for conversion
+  sourceIllegal     // source sequence is illegal/malformed
+} ConversionResult;
+
+ConversionResult convertUTF16ToUTF8(const UChar** sourceStart,
+                                    const UChar* sourceEnd, char** targetStart,
+                                    char* targetEnd, bool strict) {
+  ConversionResult result = conversionOK;
+  const UChar* source = *sourceStart;
+  char* target = *targetStart;
+  while (source < sourceEnd) {
+    UChar32 ch;
+    unsigned short bytesToWrite = 0;
+    const UChar32 byteMask = 0xBF;
+    const UChar32 byteMark = 0x80;
+    const UChar* oldSource =
+        source;  // In case we have to back up because of target overflow.
+    ch = static_cast<unsigned short>(*source++);
+    // If we have a surrogate pair, convert to UChar32 first.
+    if (ch >= 0xD800 && ch <= 0xDBFF) {
+      // If the 16 bits following the high surrogate are in the source buffer...
+      if (source < sourceEnd) {
+        UChar32 ch2 = static_cast<unsigned short>(*source);
+        // If it's a low surrogate, convert to UChar32.
+        if (ch2 >= 0xDC00 && ch2 <= 0xDFFF) {
+          ch = ((ch - 0xD800) << 10) + (ch2 - 0xDC00) + 0x0010000;
+          ++source;
+        } else if (strict) {  // it's an unpaired high surrogate
+          --source;           // return to the illegal value itself
+          result = sourceIllegal;
+          break;
+        }
+      } else {     // We don't have the 16 bits following the high surrogate.
+        --source;  // return to the high surrogate
+        result = sourceExhausted;
+        break;
+      }
+    } else if (strict) {
+      // UTF-16 surrogate values are illegal in UTF-32
+      if (ch >= 0xDC00 && ch <= 0xDFFF) {
+        --source;  // return to the illegal value itself
+        result = sourceIllegal;
+        break;
+      }
+    }
+    // Figure out how many bytes the result will require
+    if (ch < (UChar32)0x80) {
+      bytesToWrite = 1;
+    } else if (ch < (UChar32)0x800) {
+      bytesToWrite = 2;
+    } else if (ch < (UChar32)0x10000) {
+      bytesToWrite = 3;
+    } else if (ch < (UChar32)0x110000) {
+      bytesToWrite = 4;
+    } else {
+      bytesToWrite = 3;
+      ch = replacementCharacter;
+    }
+
+    target += bytesToWrite;
+    if (target > targetEnd) {
+      source = oldSource;  // Back up source pointer!
+      target -= bytesToWrite;
+      result = targetExhausted;
+      break;
+    }
+    switch (bytesToWrite) {  // note: everything falls through.
+      case 4:
+        *--target = (char)((ch | byteMark) & byteMask);
+        ch >>= 6;
+      case 3:
+        *--target = (char)((ch | byteMark) & byteMask);
+        ch >>= 6;
+      case 2:
+        *--target = (char)((ch | byteMark) & byteMask);
+        ch >>= 6;
+      case 1:
+        *--target = (char)(ch | firstByteMark[bytesToWrite]);
+    }
+    target += bytesToWrite;
+  }
+  *sourceStart = source;
+  *targetStart = target;
+  return result;
+}
+
+/**
+ * Is this code point a BMP code point (U+0000..U+ffff)?
+ * @param c 32-bit code point
+ * @return TRUE or FALSE
+ * @stable ICU 2.8
+ */
+#define U_IS_BMP(c) ((uint32_t)(c) <= 0xffff)
+
+/**
+ * Is this code point a supplementary code point (U+10000..U+10ffff)?
+ * @param c 32-bit code point
+ * @return TRUE or FALSE
+ * @stable ICU 2.8
+ */
+#define U_IS_SUPPLEMENTARY(c) ((uint32_t)((c)-0x10000) <= 0xfffff)
+
+/**
+ * Is this code point a surrogate (U+d800..U+dfff)?
+ * @param c 32-bit code point
+ * @return TRUE or FALSE
+ * @stable ICU 2.4
+ */
+#define U_IS_SURROGATE(c) (((c)&0xfffff800) == 0xd800)
+
+/**
+ * Get the lead surrogate (0xd800..0xdbff) for a
+ * supplementary code point (0x10000..0x10ffff).
+ * @param supplementary 32-bit code point (U+10000..U+10ffff)
+ * @return lead surrogate (U+d800..U+dbff) for supplementary
+ * @stable ICU 2.4
+ */
+#define U16_LEAD(supplementary) (UChar)(((supplementary) >> 10) + 0xd7c0)
+
+/**
+ * Get the trail surrogate (0xdc00..0xdfff) for a
+ * supplementary code point (0x10000..0x10ffff).
+ * @param supplementary 32-bit code point (U+10000..U+10ffff)
+ * @return trail surrogate (U+dc00..U+dfff) for supplementary
+ * @stable ICU 2.4
+ */
+#define U16_TRAIL(supplementary) (UChar)(((supplementary)&0x3ff) | 0xdc00)
+
+// This must be called with the length pre-determined by the first byte.
+// If presented with a length > 4, this returns false.  The Unicode
+// definition of UTF-8 goes up to 4-byte sequences.
+static bool isLegalUTF8(const unsigned char* source, int length) {
+  unsigned char a;
+  const unsigned char* srcptr = source + length;
+  switch (length) {
+    default:
+      return false;
+    // Everything else falls through when "true"...
+    case 4:
+      if ((a = (*--srcptr)) < 0x80 || a > 0xBF) return false;
+    case 3:
+      if ((a = (*--srcptr)) < 0x80 || a > 0xBF) return false;
+    case 2:
+      if ((a = (*--srcptr)) > 0xBF) return false;
+
+      // no fall-through in this inner switch
+      switch (*source) {
+        case 0xE0:
+          if (a < 0xA0) return false;
+          break;
+        case 0xED:
+          if (a > 0x9F) return false;
+          break;
+        case 0xF0:
+          if (a < 0x90) return false;
+          break;
+        case 0xF4:
+          if (a > 0x8F) return false;
+          break;
+        default:
+          if (a < 0x80) return false;
+      }
+
+    case 1:
+      if (*source >= 0x80 && *source < 0xC2) return false;
+  }
+  if (*source > 0xF4) return false;
+  return true;
+}
+
+// Magic values subtracted from a buffer value during UTF8 conversion.
+// This table contains as many values as there might be trailing bytes
+// in a UTF-8 sequence.
+static const UChar32 offsetsFromUTF8[6] = {0x00000000UL,
+                                           0x00003080UL,
+                                           0x000E2080UL,
+                                           0x03C82080UL,
+                                           static_cast<UChar32>(0xFA082080UL),
+                                           static_cast<UChar32>(0x82082080UL)};
+
+static inline UChar32 readUTF8Sequence(const char*& sequence, unsigned length) {
+  UChar32 character = 0;
+
+  // The cases all fall through.
+  switch (length) {
+    case 6:
+      character += static_cast<unsigned char>(*sequence++);
+      character <<= 6;
+    case 5:
+      character += static_cast<unsigned char>(*sequence++);
+      character <<= 6;
+    case 4:
+      character += static_cast<unsigned char>(*sequence++);
+      character <<= 6;
+    case 3:
+      character += static_cast<unsigned char>(*sequence++);
+      character <<= 6;
+    case 2:
+      character += static_cast<unsigned char>(*sequence++);
+      character <<= 6;
+    case 1:
+      character += static_cast<unsigned char>(*sequence++);
+  }
+
+  return character - offsetsFromUTF8[length - 1];
+}
+
+ConversionResult convertUTF8ToUTF16(const char** sourceStart,
+                                    const char* sourceEnd, UChar** targetStart,
+                                    UChar* targetEnd, bool* sourceAllASCII,
+                                    bool strict) {
+  ConversionResult result = conversionOK;
+  const char* source = *sourceStart;
+  UChar* target = *targetStart;
+  UChar orAllData = 0;
+  while (source < sourceEnd) {
+    int utf8SequenceLength = inlineUTF8SequenceLength(*source);
+    if (sourceEnd - source < utf8SequenceLength) {
+      result = sourceExhausted;
+      break;
+    }
+    // Do this check whether lenient or strict
+    if (!isLegalUTF8(reinterpret_cast<const unsigned char*>(source),
+                     utf8SequenceLength)) {
+      result = sourceIllegal;
+      break;
+    }
+
+    UChar32 character = readUTF8Sequence(source, utf8SequenceLength);
+
+    if (target >= targetEnd) {
+      source -= utf8SequenceLength;  // Back up source pointer!
+      result = targetExhausted;
+      break;
+    }
+
+    if (U_IS_BMP(character)) {
+      // UTF-16 surrogate values are illegal in UTF-32
+      if (U_IS_SURROGATE(character)) {
+        if (strict) {
+          source -= utf8SequenceLength;  // return to the illegal value itself
+          result = sourceIllegal;
+          break;
+        }
+        *target++ = replacementCharacter;
+        orAllData |= replacementCharacter;
+      } else {
+        *target++ = static_cast<UChar>(character);  // normal case
+        orAllData |= character;
+      }
+    } else if (U_IS_SUPPLEMENTARY(character)) {
+      // target is a character in range 0xFFFF - 0x10FFFF
+      if (target + 1 >= targetEnd) {
+        source -= utf8SequenceLength;  // Back up source pointer!
+        result = targetExhausted;
+        break;
+      }
+      *target++ = U16_LEAD(character);
+      *target++ = U16_TRAIL(character);
+      orAllData = 0xffff;
+    } else {
+      if (strict) {
+        source -= utf8SequenceLength;  // return to the start
+        result = sourceIllegal;
+        break;  // Bail out; shouldn't continue
+      } else {
+        *target++ = replacementCharacter;
+        orAllData |= replacementCharacter;
+      }
+    }
+  }
+  *sourceStart = source;
+  *targetStart = target;
+
+  if (sourceAllASCII) *sourceAllASCII = !(orAllData & ~0x7f);
+
+  return result;
+}
+
+// Helper to write a three-byte UTF-8 code point to the buffer, caller must
+// check room is available.
+static inline void putUTF8Triple(char*& buffer, UChar ch) {
+  *buffer++ = static_cast<char>(((ch >> 12) & 0x0F) | 0xE0);
+  *buffer++ = static_cast<char>(((ch >> 6) & 0x3F) | 0x80);
+  *buffer++ = static_cast<char>((ch & 0x3F) | 0x80);
+}
+
+}  // namespace
+
+// static
+String16 String16::fromInteger(int number) {
+  const size_t kBufferSize = 50;
+  char buffer[kBufferSize];
+  std::snprintf(buffer, kBufferSize, "%d", number);
+  return String16(buffer);
+}
+
+// static
+String16 String16::fromDouble(double number) {
+  const size_t kBufferSize = 100;
+  char buffer[kBufferSize];
+  std::snprintf(buffer, kBufferSize, "%f", number);
+  return String16(buffer);
+}
+
+// static
+String16 String16::fromDoublePrecision3(double number) {
+  const size_t kBufferSize = 100;
+  char buffer[kBufferSize];
+  std::snprintf(buffer, kBufferSize, "%.3g", number);
+  return String16(buffer);
+}
+
+// static
+String16 String16::fromDoublePrecision6(double number) {
+  const size_t kBufferSize = 100;
+  char buffer[kBufferSize];
+  std::snprintf(buffer, kBufferSize, "%.6g", number);
+  return String16(buffer);
+}
+
+int String16::toInteger(bool* ok) const {
+  return charactersToInteger(characters16(), length(), ok);
+}
+
+String16 String16::stripWhiteSpace() const {
+  if (!length()) return String16();
+
+  unsigned start = 0;
+  unsigned end = length() - 1;
+
+  // skip white space from start
+  while (start <= end && isSpaceOrNewLine(characters16()[start])) ++start;
+
+  // only white space
+  if (start > end) return String16();
+
+  // skip white space from end
+  while (end && isSpaceOrNewLine(characters16()[end])) --end;
+
+  if (!start && end == length() - 1) return *this;
+  return String16(characters16() + start, end + 1 - start);
+}
+
+String16Builder::String16Builder() {}
+
+void String16Builder::append(const String16& s) {
+  m_buffer.insert(m_buffer.end(), s.characters16(),
+                  s.characters16() + s.length());
+}
+
+void String16Builder::append(UChar c) { m_buffer.push_back(c); }
+
+void String16Builder::append(char c) {
+  UChar u = c;
+  m_buffer.push_back(u);
+}
+
+void String16Builder::append(const UChar* characters, size_t length) {
+  m_buffer.insert(m_buffer.end(), characters, characters + length);
+}
+
+void String16Builder::append(const char* characters, size_t length) {
+  m_buffer.insert(m_buffer.end(), characters, characters + length);
+}
+
+String16 String16Builder::toString() {
+  return String16(m_buffer.data(), m_buffer.size());
+}
+
+void String16Builder::reserveCapacity(size_t capacity) {
+  m_buffer.reserve(capacity);
+}
+
+String16 String16::fromUTF8(const char* stringStart, size_t length) {
+  if (!stringStart || !length) return String16();
+
+  std::vector<UChar> buffer(length);
+  UChar* bufferStart = buffer.data();
+
+  UChar* bufferCurrent = bufferStart;
+  const char* stringCurrent = stringStart;
+  if (convertUTF8ToUTF16(&stringCurrent, stringStart + length, &bufferCurrent,
+                         bufferCurrent + buffer.size(), 0,
+                         true) != conversionOK)
+    return String16();
+
+  unsigned utf16Length = bufferCurrent - bufferStart;
+  return String16(bufferStart, utf16Length);
+}
+
+std::string String16::utf8() const {
+  unsigned length = this->length();
+
+  if (!length) return std::string("");
+
+  // Allocate a buffer big enough to hold all the characters
+  // (an individual UTF-16 UChar can only expand to 3 UTF-8 bytes).
+  // Optimization ideas, if we find this function is hot:
+  //  * We could speculatively create a CStringBuffer to contain 'length'
+  //    characters, and resize if necessary (i.e. if the buffer contains
+  //    non-ascii characters). (Alternatively, scan the buffer first for
+  //    ascii characters, so we know this will be sufficient).
+  //  * We could allocate a CStringBuffer with an appropriate size to
+  //    have a good chance of being able to write the string into the
+  //    buffer without reallocing (say, 1.5 x length).
+  if (length > std::numeric_limits<unsigned>::max() / 3) return std::string();
+  std::vector<char> bufferVector(length * 3);
+  char* buffer = bufferVector.data();
+  const UChar* characters = m_impl.data();
+
+  ConversionResult result =
+      convertUTF16ToUTF8(&characters, characters + length, &buffer,
+                         buffer + bufferVector.size(), false);
+  DCHECK(
+      result !=
+      targetExhausted);  // (length * 3) should be sufficient for any conversion
+
+  // Only produced from strict conversion.
+  DCHECK(result != sourceIllegal);
+
+  // Check for an unconverted high surrogate.
+  if (result == sourceExhausted) {
+    // This should be one unpaired high surrogate. Treat it the same
+    // was as an unpaired high surrogate would have been handled in
+    // the middle of a string with non-strict conversion - which is
+    // to say, simply encode it to UTF-8.
+    DCHECK((characters + 1) == (m_impl.data() + length));
+    DCHECK((*characters >= 0xD800) && (*characters <= 0xDBFF));
+    // There should be room left, since one UChar hasn't been
+    // converted.
+    DCHECK((buffer + 3) <= (buffer + bufferVector.size()));
+    putUTF8Triple(buffer, *characters);
+  }
+
+  return std::string(bufferVector.data(), buffer - bufferVector.data());
+}
+
+}  // namespace v8_inspector