Update //third_party/protobuf to version 3.

third_party/protobuf/src/google/protobuf/util/internal/json_escaping.cc

Index: third_party/protobuf/src/google/protobuf/util/internal/json_escaping.cc
diff --git a/third_party/protobuf/src/google/protobuf/util/internal/json_escaping.cc b/third_party/protobuf/src/google/protobuf/util/internal/json_escaping.cc
new file mode 100644
index 0000000000000000000000000000000000000000..24bd554ea3893ab5b5086ea60a2bfcf67dfb922d
--- /dev/null
+++ b/third_party/protobuf/src/google/protobuf/util/internal/json_escaping.cc
@@ -0,0 +1,404 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include <google/protobuf/util/internal/json_escaping.h>
+
+#include <google/protobuf/stubs/logging.h>
+#include <google/protobuf/stubs/common.h>
+
+namespace google {
+namespace protobuf {
+namespace util {
+namespace converter {
+
+namespace {
+
+// Array of hex characters for conversion to hex.
+static const char kHex[] = "0123456789abcdef";
+
+// Characters 0x00 to 0x9f are very commonly used, so we provide a special
+// table lookup.
+//
+// For unicode code point ch < 0xa0:
+// kCommonEscapes[ch] is the escaped string of ch, if escaping is needed;
+//                    or an empty string, if escaping is not needed.
+static const char kCommonEscapes[160][7] = {
+  // C0 (ASCII and derivatives) control characters
+  "\\u0000", "\\u0001", "\\u0002", "\\u0003",  // 0x00
+  "\\u0004", "\\u0005", "\\u0006", "\\u0007",
+  "\\b",     "\\t",     "\\n",     "\\u000b",
+  "\\f",     "\\r",     "\\u000e", "\\u000f",
+  "\\u0010", "\\u0011", "\\u0012", "\\u0013",  // 0x10
+  "\\u0014", "\\u0015", "\\u0016", "\\u0017",
+  "\\u0018", "\\u0019", "\\u001a", "\\u001b",
+  "\\u001c", "\\u001d", "\\u001e", "\\u001f",
+  // Escaping of " and \ are required by www.json.org string definition.
+  // Escaping of < and > are required for HTML security.
+  "", "", "\\\"", "", "",        "", "",        "",  // 0x20
+  "", "", "",     "", "",        "", "",        "",
+  "", "", "",     "", "",        "", "",        "",  // 0x30
+  "", "", "",     "", "\\u003c", "", "\\u003e", "",
+  "", "", "",     "", "",        "", "",        "",  // 0x40
+  "", "", "",     "", "",        "", "",        "",
+  "", "", "",     "", "",        "", "",        "",  // 0x50
+  "", "", "",     "", "\\\\",    "", "",        "",
+  "", "", "",     "", "",        "", "",        "",  // 0x60
+  "", "", "",     "", "",        "", "",        "",
+  "", "", "",     "", "",        "", "",        "",  // 0x70
+  "", "", "",     "", "",        "", "",        "\\u007f",
+  // C1 (ISO 8859 and Unicode) extended control characters
+  "\\u0080", "\\u0081", "\\u0082", "\\u0083",  // 0x80
+  "\\u0084", "\\u0085", "\\u0086", "\\u0087",
+  "\\u0088", "\\u0089", "\\u008a", "\\u008b",
+  "\\u008c", "\\u008d", "\\u008e", "\\u008f",
+  "\\u0090", "\\u0091", "\\u0092", "\\u0093",  // 0x90
+  "\\u0094", "\\u0095", "\\u0096", "\\u0097",
+  "\\u0098", "\\u0099", "\\u009a", "\\u009b",
+  "\\u009c", "\\u009d", "\\u009e", "\\u009f"
+};
+
+// Determines if the given char value is a unicode high-surrogate code unit.
+// Such values do not represent characters by themselves, but are used in the
+// representation of supplementary characters in the utf-16 encoding.
+inline bool IsHighSurrogate(uint16 c) {
+  // Optimized form of:
+  // return c >= kMinHighSurrogate && c <= kMaxHighSurrogate;
+  // (Reduced from 3 ALU instructions to 2 ALU instructions)
+  return (c & ~(JsonEscaping::kMaxHighSurrogate -
+                JsonEscaping::kMinHighSurrogate))
+      == JsonEscaping::kMinHighSurrogate;
+}
+
+// Determines if the given char value is a unicode low-surrogate code unit.
+// Such values do not represent characters by themselves, but are used in the
+// representation of supplementary characters in the utf-16 encoding.
+inline bool IsLowSurrogate(uint16 c) {
+  // Optimized form of:
+  // return c >= kMinLowSurrogate && c <= kMaxLowSurrogate;
+  // (Reduced from 3 ALU instructions to 2 ALU instructions)
+  return (c & ~(JsonEscaping::kMaxLowSurrogate -
+                JsonEscaping::kMinLowSurrogate))
+      == JsonEscaping::kMinLowSurrogate;
+}
+
+// Determines if the given char value is a unicode surrogate code unit (either
+// high-surrogate or low-surrogate).
+inline bool IsSurrogate(uint32 c) {
+  // Optimized form of:
+  // return c >= kMinHighSurrogate && c <= kMaxLowSurrogate;
+  // (Reduced from 3 ALU instructions to 2 ALU instructions)
+  return (c & 0xfffff800) == JsonEscaping::kMinHighSurrogate;
+}
+
+// Returns true if the given unicode code point cp is
+// in the supplementary character range.
+inline bool IsSupplementalCodePoint(uint32 cp) {
+  // Optimized form of:
+  // return kMinSupplementaryCodePoint <= cp && cp <= kMaxCodePoint;
+  // (Reduced from 3 ALU instructions to 2 ALU instructions)
+  return (cp & ~(JsonEscaping::kMinSupplementaryCodePoint - 1))
+      < JsonEscaping::kMaxCodePoint;
+}
+
+// Returns true if the given unicode code point cp is a valid
+// unicode code point (i.e. in the range 0 <= cp <= kMaxCodePoint).
+inline bool IsValidCodePoint(uint32 cp) {
+  return cp <= JsonEscaping::kMaxCodePoint;
+}
+
+// Converts the specified surrogate pair to its supplementary code point value.
+// It is the callers' responsibility to validate the specified surrogate pair.
+inline uint32 ToCodePoint(uint16 high, uint16 low) {
+  // Optimized form of:
+  // return ((high - kMinHighSurrogate) << 10)
+  //     + (low - kMinLowSurrogate)
+  //     + kMinSupplementaryCodePoint;
+  // (Reduced from 5 ALU instructions to 3 ALU instructions)
+  return (high << 10) + low +
+      (JsonEscaping::kMinSupplementaryCodePoint
+       - (static_cast<unsigned>(JsonEscaping::kMinHighSurrogate) << 10)
+       - JsonEscaping::kMinLowSurrogate);
+}
+
+// Returns the low surrogate for the given unicode code point. The result is
+// meaningless if the given code point is not a supplementary character.
+inline uint16 ToLowSurrogate(uint32 cp) {
+  return (cp & (JsonEscaping::kMaxLowSurrogate
+                - JsonEscaping::kMinLowSurrogate))
+      + JsonEscaping::kMinLowSurrogate;
+}
+
+// Returns the high surrogate for the given unicode code point. The result is
+// meaningless if the given code point is not a supplementary character.
+inline uint16 ToHighSurrogate(uint32 cp) {
+  return (cp >> 10) + (JsonEscaping::kMinHighSurrogate -
+                       (JsonEscaping::kMinSupplementaryCodePoint >> 10));
+}
+
+// Input str is encoded in UTF-8. A unicode code point could be encoded in
+// UTF-8 using anywhere from 1 to 4 characters, and it could span multiple
+// reads of the ByteSource.
+//
+// This function reads the next unicode code point from the input (str) at
+// the given position (index), taking into account any left-over partial
+// code point from the previous iteration (cp), together with the number
+// of characters left to read to complete this code point (num_left).
+//
+// This function assumes that the input (str) is valid at the given position
+// (index). In order words, at least one character could be read successfully.
+//
+// The code point read (partial or complete) is stored in (cp). Upon return,
+// (num_left) stores the number of characters that has yet to be read in
+// order to complete the current unicode code point. If the read is complete,
+// then (num_left) is 0. Also, (num_read) is the number of characters read.
+//
+// Returns false if we encounter an invalid UTF-8 string. Returns true
+// otherwise, including the case when we reach the end of the input (str)
+// before a complete unicode code point is read.
+bool ReadCodePoint(StringPiece str, int index,
+                   uint32 *cp, int* num_left, int *num_read) {
+  if (*num_left == 0) {
+    // Last read was complete. Start reading a new unicode code point.
+    *cp = static_cast<uint8>(str[index++]);
+    *num_read = 1;
+    // The length of the code point is determined from reading the first byte.
+    //
+    // If the first byte is between:
+    //    0..0x7f: that's the value of the code point.
+    // 0x80..0xbf: <invalid>
+    // 0xc0..0xdf: 11-bit code point encoded in 2 bytes.
+    //                                   bit 10-6, bit 5-0
+    // 0xe0..0xef: 16-bit code point encoded in 3 bytes.
+    //                        bit 15-12, bit 11-6, bit 5-0
+    // 0xf0..0xf7: 21-bit code point encoded in 4 bytes.
+    //             bit 20-18, bit 17-12, bit 11-6, bit 5-0
+    // 0xf8..0xff: <invalid>
+    //
+    // Meaning of each bit:
+    // <msb> bit 7: 0 - single byte code point: bits 6-0 are values.
+    //              1 - multibyte code point
+    //       bit 6: 0 - subsequent bytes of multibyte code point:
+    //                  bits 5-0 are values.
+    //              1 - first byte of multibyte code point
+    //       bit 5: 0 - first byte of 2-byte code point: bits 4-0 are values.
+    //              1 - first byte of code point with >= 3 bytes.
+    //       bit 4: 0 - first byte of 3-byte code point: bits 3-0 are values.
+    //              1 - first byte of code point with >= 4 bytes.
+    //       bit 3: 0 - first byte of 4-byte code point: bits 2-0 are values.
+    //              1 - reserved for future expansion.
+    if (*cp <= 0x7f) {
+      return true;
+    } else if (*cp <= 0xbf) {
+      return false;
+    } else if (*cp <= 0xdf) {
+      *cp &= 0x1f;
+      *num_left = 1;
+    } else if (*cp <= 0xef) {
+      *cp &= 0x0f;
+      *num_left = 2;
+    } else if (*cp <= 0xf7) {
+      *cp &= 0x07;
+      *num_left = 3;
+    } else {
+      return false;
+    }
+  } else {
+    // Last read was partial. Initialize num_read to 0 and continue reading
+    // the last unicode code point.
+    *num_read = 0;
+  }
+  while (*num_left > 0 && index < str.size()) {
+    uint32 ch = static_cast<uint8>(str[index++]);
+    --(*num_left);
+    ++(*num_read);
+    *cp = (*cp << 6) | (ch & 0x3f);
+    if (ch < 0x80 || ch > 0xbf) return false;
+  }
+  return *num_left > 0 || (!IsSurrogate(*cp) && IsValidCodePoint(*cp));
+}
+
+// Stores the 16-bit unicode code point as its hexadecimal digits in buffer
+// and returns a StringPiece that points to this buffer. The input buffer needs
+// to be at least 6 bytes long.
+StringPiece ToHex(uint16 cp, char* buffer) {
+  buffer[5] = kHex[cp & 0x0f];
+  cp >>= 4;
+  buffer[4] = kHex[cp & 0x0f];
+  cp >>= 4;
+  buffer[3] = kHex[cp & 0x0f];
+  cp >>= 4;
+  buffer[2] = kHex[cp & 0x0f];
+  return StringPiece(buffer, 0, 6);
+}
+
+// Stores the 32-bit unicode code point as its hexadecimal digits in buffer
+// and returns a StringPiece that points to this buffer. The input buffer needs
+// to be at least 12 bytes long.
+StringPiece ToSurrogateHex(uint32 cp, char* buffer) {
+  uint16 low = ToLowSurrogate(cp);
+  uint16 high = ToHighSurrogate(cp);
+
+  buffer[11] = kHex[low & 0x0f];
+  low >>= 4;
+  buffer[10] = kHex[low & 0x0f];
+  low >>= 4;
+  buffer[9] = kHex[low & 0x0f];
+  low >>= 4;
+  buffer[8] = kHex[low & 0x0f];
+
+  buffer[5] = kHex[high & 0x0f];
+  high >>= 4;
+  buffer[4] = kHex[high & 0x0f];
+  high >>= 4;
+  buffer[3] = kHex[high & 0x0f];
+  high >>= 4;
+  buffer[2] = kHex[high & 0x0f];
+
+  return StringPiece(buffer, 12);
+}
+
+// If the given unicode code point needs escaping, then returns the
+// escaped form. The returned StringPiece either points to statically
+// pre-allocated char[] or to the given buffer. The input buffer needs
+// to be at least 12 bytes long.
+//
+// If the given unicode code point does not need escaping, an empty
+// StringPiece is returned.
+StringPiece EscapeCodePoint(uint32 cp, char* buffer) {
+  if (cp < 0xa0) return kCommonEscapes[cp];
+  switch (cp) {
+    // These are not required by json spec
+    // but used to prevent security bugs in javascript.
+    case 0xfeff:  // Zero width no-break space
+    case 0xfff9:  // Interlinear annotation anchor
+    case 0xfffa:  // Interlinear annotation separator
+    case 0xfffb:  // Interlinear annotation terminator
+
+    case 0x00ad:  // Soft-hyphen
+    case 0x06dd:  // Arabic end of ayah
+    case 0x070f:  // Syriac abbreviation mark
+    case 0x17b4:  // Khmer vowel inherent Aq
+    case 0x17b5:  // Khmer vowel inherent Aa
+      return ToHex(cp, buffer);
+
+    default:
+      if ((cp >= 0x0600 && cp <= 0x0603) ||  // Arabic signs
+          (cp >= 0x200b && cp <= 0x200f) ||  // Zero width etc.
+          (cp >= 0x2028 && cp <= 0x202e) ||  // Separators etc.
+          (cp >= 0x2060 && cp <= 0x2064) ||  // Invisible etc.
+          (cp >= 0x206a && cp <= 0x206f)) {  // Shaping etc.
+        return ToHex(cp, buffer);
+      }
+
+      if (cp == 0x000e0001 ||                        // Language tag
+          (cp >= 0x0001d173 && cp <= 0x0001d17a) ||  // Music formatting
+          (cp >= 0x000e0020 && cp <= 0x000e007f)) {  // TAG symbols
+        return ToSurrogateHex(cp, buffer);
+      }
+  }
+  return StringPiece();
+}
+
+// Tries to escape the given code point first. If the given code point
+// does not need to be escaped, but force_output is true, then render
+// the given multi-byte code point in UTF8 in the buffer and returns it.
+StringPiece EscapeCodePoint(uint32 cp, char* buffer, bool force_output) {
+  StringPiece sp = EscapeCodePoint(cp, buffer);
+  if (force_output && sp.empty()) {
+    buffer[5] = (cp & 0x3f) | 0x80;
+    cp >>= 6;
+    if (cp <= 0x1f) {
+      buffer[4] = cp | 0xc0;
+      sp.set(buffer + 4, 2);
+      return sp;
+    }
+    buffer[4] = (cp & 0x3f) | 0x80;
+    cp >>= 6;
+    if (cp <= 0x0f) {
+      buffer[3] = cp | 0xe0;
+      sp.set(buffer + 3, 3);
+      return sp;
+    }
+    buffer[3] = (cp & 0x3f) | 0x80;
+    buffer[2] = ((cp >> 6) & 0x07) | 0xf0;
+    sp.set(buffer + 2, 4);
+  }
+  return sp;
+}
+
+}  // namespace
+
+void JsonEscaping::Escape(strings::ByteSource* input,
+                          strings::ByteSink* output) {
+  char buffer[12] = "\\udead\\ubee";
+  uint32 cp = 0;     // Current unicode code point.
+  int num_left = 0;  // Num of chars to read to complete the code point.
+  while (input->Available() > 0) {
+    StringPiece str = input->Peek();
+    StringPiece escaped;
+    int i = 0;
+    int num_read;
+    bool ok;
+    bool cp_was_split = num_left > 0;
+    // Loop until we encounter either
+    //   i) a code point that needs to be escaped; or
+    //  ii) a split code point is completely read; or
+    // iii) a character that is not a valid utf8; or
+    //  iv) end of the StringPiece str is reached.
+    do {
+      ok = ReadCodePoint(str, i, &cp, &num_left, &num_read);
+      if (num_left > 0 || !ok) break;  // case iii or iv
+      escaped = EscapeCodePoint(cp, buffer, cp_was_split);
+      if (!escaped.empty()) break;     // case i or ii
+      i += num_read;
+      num_read = 0;
+    } while (i < str.length());        // case iv
+    // First copy the un-escaped prefix, if any, to the output ByteSink.
+    if (i > 0) input->CopyTo(output, i);
+    if (num_read > 0) input->Skip(num_read);
+    if (!ok) {
+      // Case iii: Report error.
+      // TODO(wpoon): Add error reporting.
+      num_left = 0;
+    } else if (num_left == 0 && !escaped.empty()) {
+      // Case i or ii: Append the escaped code point to the output ByteSink.
+      output->Append(escaped.data(), escaped.size());
+    }
+  }
+  if (num_left > 0) {
+    // Treat as case iii: report error.
+    // TODO(wpoon): Add error reporting.
+  }
+}
+
+}  // namespace converter
+}  // namespace util
+}  // namespace protobuf
+}  // namespace google