Revert https://codereview.chromium.org/1291903002 (protobuf roll).

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
deleted file mode 100644
index 5ac23421caa013effd9799ec6ed2e25f34e5a618..0000000000000000000000000000000000000000
--- a/third_party/protobuf/src/google/protobuf/util/internal/json_escaping.cc
+++ /dev/null
@@ -1,403 +0,0 @@
-// 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/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 = 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 = 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