X-Git-Url: http://plrg.eecs.uci.edu/git/?p=folly.git;a=blobdiff_plain;f=folly%2Fjson.cpp;h=db80b332a9b0c5825aa1a5f47f886f77993b11e6;hp=4fb7d04acb131320c3100e21c20b796fb685ae49;hb=bca34971c398bb8f5f258dba57206068bfd29937;hpb=ad925ffabc3a5d452927242efdff0ba70f34626d diff --git a/folly/json.cpp b/folly/json.cpp index 4fb7d04a..db80b332 100644 --- a/folly/json.cpp +++ b/folly/json.cpp @@ -1,5 +1,5 @@ /* - * Copyright 2016 Facebook, Inc. + * Copyright 2017 Facebook, Inc. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. @@ -15,12 +15,17 @@ */ #include -#include -#include + +#include +#include +#include + #include +#include +#include +#include #include -#include #include #include #include @@ -33,98 +38,12 @@ namespace folly { namespace json { namespace { -char32_t decodeUtf8( - const unsigned char*& p, - const unsigned char* const e, - bool skipOnError) { - /* The following encodings are valid, except for the 5 and 6 byte - * combinations: - * 0xxxxxxx - * 110xxxxx 10xxxxxx - * 1110xxxx 10xxxxxx 10xxxxxx - * 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx - * 111110xx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx - * 1111110x 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx - */ - - auto skip = [&] { ++p; return U'\ufffd'; }; - - if (p >= e) { - if (skipOnError) return skip(); - throw std::runtime_error("folly::decodeUtf8 empty/invalid string"); - } - - unsigned char fst = *p; - if (!(fst & 0x80)) { - // trivial case - return *p++; - } - - static const uint32_t bitMask[] = { - (1 << 7) - 1, - (1 << 11) - 1, - (1 << 16) - 1, - (1 << 21) - 1 - }; - - // upper control bits are masked out later - uint32_t d = fst; - - if ((fst & 0xC0) != 0xC0) { - if (skipOnError) return skip(); - throw std::runtime_error(to("folly::decodeUtf8 i=0 d=", d)); - } - - fst <<= 1; - - for (unsigned int i = 1; i != 3 && p + i < e; ++i) { - unsigned char tmp = p[i]; - - if ((tmp & 0xC0) != 0x80) { - if (skipOnError) return skip(); - throw std::runtime_error( - to("folly::decodeUtf8 i=", i, " tmp=", (uint32_t)tmp)); - } - - d = (d << 6) | (tmp & 0x3F); - fst <<= 1; - - if (!(fst & 0x80)) { - d &= bitMask[i]; - - // overlong, could have been encoded with i bytes - if ((d & ~bitMask[i - 1]) == 0) { - if (skipOnError) return skip(); - throw std::runtime_error( - to("folly::decodeUtf8 i=", i, " d=", d)); - } - - // check for surrogates only needed for 3 bytes - if (i == 2) { - if ((d >= 0xD800 && d <= 0xDFFF) || d > 0x10FFFF) { - if (skipOnError) return skip(); - throw std::runtime_error( - to("folly::decodeUtf8 i=", i, " d=", d)); - } - } - - p += i + 1; - return d; - } - } - - if (skipOnError) return skip(); - throw std::runtime_error("folly::decodeUtf8 encoding length maxed out"); -} - struct Printer { - explicit Printer(fbstring& out, - unsigned* indentLevel, - serialization_opts const* opts) - : out_(out) - , indentLevel_(indentLevel) - , opts_(*opts) - {} + explicit Printer( + std::string& out, + unsigned* indentLevel, + serialization_opts const* opts) + : out_(out), indentLevel_(indentLevel), opts_(*opts) {} void operator()(dynamic const& v) const { switch (v.type()) { @@ -166,7 +85,7 @@ struct Printer { } } -private: + private: void printKV(const std::pair& p) const { if (!opts_.allow_non_string_keys && !p.first.isString()) { throw std::runtime_error("folly::toJson: JSON object key was not a " @@ -196,11 +115,19 @@ private: out_ += '{'; indent(); newline(); - if (opts_.sort_keys) { - std::vector> items( - o.items().begin(), o.items().end()); - std::sort(items.begin(), items.end()); - printKVPairs(items.begin(), items.end()); + if (opts_.sort_keys || opts_.sort_keys_by) { + using ref = std::reference_wrapper; + std::vector refs(o.items().begin(), o.items().end()); + + using SortByRef = FunctionRef; + auto const& sort_keys_by = opts_.sort_keys_by + ? SortByRef(opts_.sort_keys_by) + : SortByRef(std::less()); + std::sort(refs.begin(), refs.end(), [&](ref a, ref b) { + // Only compare keys. No ordering among identical keys. + return sort_keys_by(a.get().first, b.get().first); + }); + printKVPairs(refs.cbegin(), refs.cend()); } else { printKVPairs(o.items().begin(), o.items().end()); } @@ -229,7 +156,7 @@ private: out_ += ']'; } -private: + private: void outdent() const { if (indentLevel_) { --*indentLevel_; @@ -244,7 +171,7 @@ private: void newline() const { if (indentLevel_) { - out_ += to('\n', fbstring(*indentLevel_ * 2, ' ')); + out_ += to('\n', std::string(*indentLevel_ * 2, ' ')); } } @@ -252,31 +179,26 @@ private: out_ += indentLevel_ ? " : " : ":"; } -private: - fbstring& out_; + private: + std::string& out_; unsigned* const indentLevel_; serialization_opts const& opts_; }; - ////////////////////////////////////////////////////////////////////// - - struct ParseError : std::runtime_error { - explicit ParseError(int line) - : std::runtime_error(to("json parse error on line ", line)) - {} - - explicit ParseError(int line, std::string const& context, - std::string const& expected) - : std::runtime_error(to("json parse error on line ", line, - !context.empty() ? to(" near `", context, '\'') - : "", - ": ", expected)) - {} +////////////////////////////////////////////////////////////////////// - explicit ParseError(std::string const& msg) - : std::runtime_error("json parse error: " + msg) - {} - }; +struct ParseError : std::runtime_error { + explicit ParseError( + unsigned int line, + std::string const& context, + std::string const& expected) + : std::runtime_error(to( + "json parse error on line ", + line, + !context.empty() ? to(" near `", context, '\'') : "", + ": ", + expected)) {} +}; // Wraps our input buffer with some helper functions. struct Input { @@ -295,7 +217,7 @@ struct Input { // Parse ahead for as long as the supplied predicate is satisfied, // returning a range of what was skipped. - template + template StringPiece skipWhile(const Predicate& p) { std::size_t skipped = 0; for (; skipped < range_.size(); ++skipped) { @@ -351,7 +273,7 @@ struct Input { storeCurrent(); } - template + template T extract() { try { return to(&range_); @@ -381,24 +303,50 @@ struct Input { return opts_; } -private: + void incrementRecursionLevel() { + if (currentRecursionLevel_ > opts_.recursion_limit) { + error("recursion limit exceeded"); + } + currentRecursionLevel_++; + } + + void decrementRecursionLevel() { + currentRecursionLevel_--; + } + + private: void storeCurrent() { current_ = range_.empty() ? EOF : range_.front(); } -private: + private: StringPiece range_; json::serialization_opts const& opts_; unsigned lineNum_; int current_; + unsigned int currentRecursionLevel_{0}; +}; + +class RecursionGuard { + public: + explicit RecursionGuard(Input& in) : in_(in) { + in_.incrementRecursionLevel(); + } + + ~RecursionGuard() { + in_.decrementRecursionLevel(); + } + + private: + Input& in_; }; dynamic parseValue(Input& in); -fbstring parseString(Input& in); +std::string parseString(Input& in); dynamic parseNumber(Input& in); dynamic parseObject(Input& in) { - assert(*in == '{'); + DCHECK_EQ(*in, '{'); ++in; dynamic ret = dynamic::object; @@ -442,10 +390,10 @@ dynamic parseObject(Input& in) { } dynamic parseArray(Input& in) { - assert(*in == '['); + DCHECK_EQ(*in, '['); ++in; - dynamic ret = {}; + dynamic ret = dynamic::array; in.skipWhitespace(); if (*in == ']') { @@ -488,9 +436,9 @@ dynamic parseNumber(Input& in) { auto const wasE = *in == 'e' || *in == 'E'; constexpr const char* maxInt = "9223372036854775807"; - constexpr const char* minInt = "9223372036854775808"; + constexpr const char* minInt = "-9223372036854775808"; constexpr auto maxIntLen = constexpr_strlen(maxInt); - + constexpr auto minIntLen = constexpr_strlen(minInt); if (*in != '.' && !wasE && in.getOpts().parse_numbers_as_strings) { return integral; @@ -498,8 +446,8 @@ dynamic parseNumber(Input& in) { if (*in != '.' && !wasE) { if (LIKELY(!in.getOpts().double_fallback || integral.size() < maxIntLen) || - (integral.size() == maxIntLen && - (integral <= maxInt || (integral == minInt && negative)))) { + (!negative && integral.size() == maxIntLen && integral <= maxInt) || + (negative && integral.size() == minIntLen && integral <= minInt)) { auto val = to(integral); in.skipWhitespace(); return val; @@ -527,12 +475,13 @@ dynamic parseNumber(Input& in) { return val; } -fbstring decodeUnicodeEscape(Input& in) { - auto hexVal = [&] (char c) -> unsigned { - return c >= '0' && c <= '9' ? c - '0' : +std::string decodeUnicodeEscape(Input& in) { + auto hexVal = [&] (int c) -> uint16_t { + return uint16_t( + c >= '0' && c <= '9' ? c - '0' : c >= 'a' && c <= 'f' ? c - 'a' + 10 : c >= 'A' && c <= 'F' ? c - 'A' + 10 : - (in.error("invalid hex digit"), 0); + (in.error("invalid hex digit"), 0)); }; auto readHex = [&]() -> uint16_t { @@ -540,7 +489,7 @@ fbstring decodeUnicodeEscape(Input& in) { in.error("expected 4 hex digits"); } - uint16_t ret = hexVal(*in) * 4096; + uint16_t ret = uint16_t(hexVal(*in) * 4096); ++in; ret += hexVal(*in) * 256; ++in; @@ -575,11 +524,11 @@ fbstring decodeUnicodeEscape(Input& in) { return codePointToUtf8(codePoint); } -fbstring parseString(Input& in) { - assert(*in == '\"'); +std::string parseString(Input& in) { + DCHECK_EQ(*in, '\"'); ++in; - fbstring ret; + std::string ret; for (;;) { auto range = in.skipWhile( [] (char c) { return c != '\"' && c != '\\'; } @@ -602,8 +551,8 @@ fbstring parseString(Input& in) { case 'r': ret.push_back('\r'); ++in; break; case 't': ret.push_back('\t'); ++in; break; case 'u': ++in; ret += decodeUnicodeEscape(in); break; - default: in.error(to("unknown escape ", *in, - " in string").c_str()); + default: + in.error(to("unknown escape ", *in, " in string").c_str()); } continue; } @@ -621,7 +570,7 @@ fbstring parseString(Input& in) { in.error("null byte in string"); } - ret.push_back(*in); + ret.push_back(char(*in)); ++in; } @@ -629,6 +578,8 @@ fbstring parseString(Input& in) { } dynamic parseValue(Input& in) { + RecursionGuard guard(in); + in.skipWhitespace(); return *in == '[' ? parseArray(in) : *in == '{' ? parseObject(in) : @@ -646,27 +597,65 @@ dynamic parseValue(Input& in) { in.error("expected json value"); } -} +} // namespace ////////////////////////////////////////////////////////////////////// -fbstring serialize(dynamic const& dyn, serialization_opts const& opts) { - fbstring ret; +std::string serialize(dynamic const& dyn, serialization_opts const& opts) { + std::string ret; unsigned indentLevel = 0; Printer p(ret, opts.pretty_formatting ? &indentLevel : nullptr, &opts); p(dyn); return ret; } +// Fast path to determine the longest prefix that can be left +// unescaped in a string of sizeof(T) bytes packed in an integer of +// type T. +template +size_t firstEscapableInWord(T s) { + static_assert(std::is_unsigned::value, "Unsigned integer required"); + static constexpr T kOnes = ~T() / 255; // 0x...0101 + static constexpr T kMsbs = kOnes * 0x80; // 0x...8080 + + // Sets the MSB of bytes < b. Precondition: b < 128. + auto isLess = [](T w, uint8_t b) { + // A byte is < b iff subtracting b underflows, so we check that + // the MSB wasn't set before and it's set after the subtraction. + return (w - kOnes * b) & ~w & kMsbs; + }; + + auto isChar = [&](uint8_t c) { + // A byte is == c iff it is 0 if xored with c. + return isLess(s ^ (kOnes * c), 1); + }; + + // The following masks have the MSB set for each byte of the word + // that satisfies the corresponding condition. + auto isHigh = s & kMsbs; // >= 128 + auto isLow = isLess(s, 0x20); // <= 0x1f + auto needsEscape = isHigh | isLow | isChar('\\') | isChar('"'); + + if (!needsEscape) { + return sizeof(T); + } + + if (folly::kIsLittleEndian) { + return folly::findFirstSet(needsEscape) / 8 - 1; + } else { + return sizeof(T) - folly::findLastSet(needsEscape) / 8; + } +} + // Escape a string so that it is legal to print it in JSON text. -void escapeString(StringPiece input, - fbstring& out, - const serialization_opts& opts) { - auto hexDigit = [] (int c) -> char { +void escapeString( + StringPiece input, + std::string& out, + const serialization_opts& opts) { + auto hexDigit = [] (uint8_t c) -> char { return c < 10 ? c + '0' : c - 10 + 'a'; }; - out.reserve(out.size() + input.size() + 2); out.push_back('\"'); auto* p = reinterpret_cast(input.begin()); @@ -674,24 +663,54 @@ void escapeString(StringPiece input, auto* e = reinterpret_cast(input.end()); while (p < e) { + // Find the longest prefix that does not need escaping, and copy + // it literally into the output string. + auto firstEsc = p; + while (firstEsc < e) { + auto avail = e - firstEsc; + uint64_t word = 0; + if (avail >= 8) { + word = folly::loadUnaligned(firstEsc); + } else { + memcpy(static_cast(&word), firstEsc, avail); + } + auto prefix = firstEscapableInWord(word); + DCHECK_LE(prefix, avail); + firstEsc += prefix; + if (prefix < 8) { + break; + } + } + if (firstEsc > p) { + out.append(reinterpret_cast(p), firstEsc - p); + p = firstEsc; + // We can't be in the middle of a multibyte sequence, so we can reset q. + q = p; + if (p == e) { + break; + } + } + + // Handle the next byte that may need escaping. + // Since non-ascii encoding inherently does utf8 validation // we explicitly validate utf8 only if non-ascii encoding is disabled. if ((opts.validate_utf8 || opts.skip_invalid_utf8) && !opts.encode_non_ascii) { - // to achieve better spatial and temporal coherence + // To achieve better spatial and temporal coherence // we do utf8 validation progressively along with the - // string-escaping instead of two separate passes + // string-escaping instead of two separate passes. - // as the encoding progresses, q will stay at or ahead of p - CHECK(q >= p); + // As the encoding progresses, q will stay at or ahead of p. + CHECK_GE(q, p); - // as p catches up with q, move q forward + // As p catches up with q, move q forward. if (q == p) { // calling utf8_decode has the side effect of // checking that utf8 encodings are valid - char32_t v = decodeUtf8(q, e, opts.skip_invalid_utf8); + char32_t v = utf8ToCodePoint(q, e, opts.skip_invalid_utf8); if (opts.skip_invalid_utf8 && v == U'\ufffd') { - out.append("\ufffd"); + out.append(u8"\ufffd"); p = q; continue; } @@ -700,15 +719,17 @@ void escapeString(StringPiece input, if (opts.encode_non_ascii && (*p & 0x80)) { // note that this if condition captures utf8 chars // with value > 127, so size > 1 byte - char32_t v = decodeUtf8(p, e, opts.skip_invalid_utf8); - out.append("\\u"); - out.push_back(hexDigit(v >> 12)); - out.push_back(hexDigit((v >> 8) & 0x0f)); - out.push_back(hexDigit((v >> 4) & 0x0f)); - out.push_back(hexDigit(v & 0x0f)); + char32_t v = utf8ToCodePoint(p, e, opts.skip_invalid_utf8); + char buf[] = "\\u\0\0\0\0"; + buf[2] = hexDigit(uint8_t(v >> 12)); + buf[3] = hexDigit((v >> 8) & 0x0f); + buf[4] = hexDigit((v >> 4) & 0x0f); + buf[5] = hexDigit(v & 0x0f); + out.append(buf, 6); } else if (*p == '\\' || *p == '\"') { - out.push_back('\\'); - out.push_back(*p++); + char buf[] = "\\\0"; + buf[1] = char(*p++); + out.append(buf, 2); } else if (*p <= 0x1f) { switch (*p) { case '\b': out.append("\\b"); p++; break; @@ -717,23 +738,24 @@ void escapeString(StringPiece input, case '\r': out.append("\\r"); p++; break; case '\t': out.append("\\t"); p++; break; default: - // note that this if condition captures non readable chars + // Note that this if condition captures non readable chars // with value < 32, so size = 1 byte (e.g control chars). - out.append("\\u00"); - out.push_back(hexDigit((*p & 0xf0) >> 4)); - out.push_back(hexDigit(*p & 0xf)); + char buf[] = "\\u00\0\0"; + buf[4] = hexDigit(uint8_t((*p & 0xf0) >> 4)); + buf[5] = hexDigit(uint8_t(*p & 0xf)); + out.append(buf, 6); p++; } } else { - out.push_back(*p++); + out.push_back(char(*p++)); } } out.push_back('\"'); } -fbstring stripComments(StringPiece jsonC) { - fbstring result; +std::string stripComments(StringPiece jsonC) { + std::string result; enum class State { None, InString, @@ -791,7 +813,7 @@ fbstring stripComments(StringPiece jsonC) { return result; } -} +} // namespace json ////////////////////////////////////////////////////////////////////// @@ -813,11 +835,11 @@ dynamic parseJson( return ret; } -fbstring toJson(dynamic const& dyn) { +std::string toJson(dynamic const& dyn) { return json::serialize(dyn, json::serialization_opts()); } -fbstring toPrettyJson(dynamic const& dyn) { +std::string toPrettyJson(dynamic const& dyn) { json::serialization_opts opts; opts.pretty_formatting = true; return json::serialize(dyn, opts); @@ -846,4 +868,4 @@ void PrintTo(const dynamic& dyn, std::ostream* os) { ////////////////////////////////////////////////////////////////////// -} +} // namespace folly