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//=== JSON.cpp - JSON value, parsing and serialization - C++ -----------*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===---------------------------------------------------------------------===//
#include "llvm/Support/JSON.h"
#include "llvm/Support/ConvertUTF.h"
#include "llvm/Support/Format.h"
#include <cctype>
namespace llvm {
namespace json {
Value &Object::operator[](const ObjectKey &K) {
return try_emplace(K, nullptr).first->getSecond();
}
Value &Object::operator[](ObjectKey &&K) {
return try_emplace(std::move(K), nullptr).first->getSecond();
}
Value *Object::get(StringRef K) {
auto I = find(K);
if (I == end())
return nullptr;
return &I->second;
}
const Value *Object::get(StringRef K) const {
auto I = find(K);
if (I == end())
return nullptr;
return &I->second;
}
llvm::Optional<std::nullptr_t> Object::getNull(StringRef K) const {
if (auto *V = get(K))
return V->getAsNull();
return llvm::None;
}
llvm::Optional<bool> Object::getBoolean(StringRef K) const {
if (auto *V = get(K))
return V->getAsBoolean();
return llvm::None;
}
llvm::Optional<double> Object::getNumber(StringRef K) const {
if (auto *V = get(K))
return V->getAsNumber();
return llvm::None;
}
llvm::Optional<int64_t> Object::getInteger(StringRef K) const {
if (auto *V = get(K))
return V->getAsInteger();
return llvm::None;
}
llvm::Optional<llvm::StringRef> Object::getString(StringRef K) const {
if (auto *V = get(K))
return V->getAsString();
return llvm::None;
}
const json::Object *Object::getObject(StringRef K) const {
if (auto *V = get(K))
return V->getAsObject();
return nullptr;
}
json::Object *Object::getObject(StringRef K) {
if (auto *V = get(K))
return V->getAsObject();
return nullptr;
}
const json::Array *Object::getArray(StringRef K) const {
if (auto *V = get(K))
return V->getAsArray();
return nullptr;
}
json::Array *Object::getArray(StringRef K) {
if (auto *V = get(K))
return V->getAsArray();
return nullptr;
}
bool operator==(const Object &LHS, const Object &RHS) {
if (LHS.size() != RHS.size())
return false;
for (const auto &L : LHS) {
auto R = RHS.find(L.first);
if (R == RHS.end() || L.second != R->second)
return false;
}
return true;
}
Array::Array(std::initializer_list<Value> Elements) {
V.reserve(Elements.size());
for (const Value &V : Elements) {
emplace_back(nullptr);
back().moveFrom(std::move(V));
}
}
Value::Value(std::initializer_list<Value> Elements)
: Value(json::Array(Elements)) {}
void Value::copyFrom(const Value &M) {
Type = M.Type;
switch (Type) {
case T_Null:
case T_Boolean:
case T_Double:
case T_Integer:
memcpy(Union.buffer, M.Union.buffer, sizeof(Union.buffer));
break;
case T_StringRef:
create<StringRef>(M.as<StringRef>());
break;
case T_String:
create<std::string>(M.as<std::string>());
break;
case T_Object:
create<json::Object>(M.as<json::Object>());
break;
case T_Array:
create<json::Array>(M.as<json::Array>());
break;
}
}
void Value::moveFrom(const Value &&M) {
Type = M.Type;
switch (Type) {
case T_Null:
case T_Boolean:
case T_Double:
case T_Integer:
memcpy(Union.buffer, M.Union.buffer, sizeof(Union.buffer));
break;
case T_StringRef:
create<StringRef>(M.as<StringRef>());
break;
case T_String:
create<std::string>(std::move(M.as<std::string>()));
M.Type = T_Null;
break;
case T_Object:
create<json::Object>(std::move(M.as<json::Object>()));
M.Type = T_Null;
break;
case T_Array:
create<json::Array>(std::move(M.as<json::Array>()));
M.Type = T_Null;
break;
}
}
void Value::destroy() {
switch (Type) {
case T_Null:
case T_Boolean:
case T_Double:
case T_Integer:
break;
case T_StringRef:
as<StringRef>().~StringRef();
break;
case T_String:
as<std::string>().~basic_string();
break;
case T_Object:
as<json::Object>().~Object();
break;
case T_Array:
as<json::Array>().~Array();
break;
}
}
bool operator==(const Value &L, const Value &R) {
if (L.kind() != R.kind())
return false;
switch (L.kind()) {
case Value::Null:
return *L.getAsNull() == *R.getAsNull();
case Value::Boolean:
return *L.getAsBoolean() == *R.getAsBoolean();
case Value::Number:
// Workaround for https://gcc.gnu.org/bugzilla/show_bug.cgi?id=323
// The same integer must convert to the same double, per the standard.
// However we see 64-vs-80-bit precision comparisons with gcc-7 -O3 -m32.
// So we avoid floating point promotion for exact comparisons.
if (L.Type == Value::T_Integer || R.Type == Value::T_Integer)
return L.getAsInteger() == R.getAsInteger();
return *L.getAsNumber() == *R.getAsNumber();
case Value::String:
return *L.getAsString() == *R.getAsString();
case Value::Array:
return *L.getAsArray() == *R.getAsArray();
case Value::Object:
return *L.getAsObject() == *R.getAsObject();
}
llvm_unreachable("Unknown value kind");
}
namespace {
// Simple recursive-descent JSON parser.
class Parser {
public:
Parser(StringRef JSON)
: Start(JSON.begin()), P(JSON.begin()), End(JSON.end()) {}
bool checkUTF8() {
size_t ErrOffset;
if (isUTF8(StringRef(Start, End - Start), &ErrOffset))
return true;
P = Start + ErrOffset; // For line/column calculation.
return parseError("Invalid UTF-8 sequence");
}
bool parseValue(Value &Out);
bool assertEnd() {
eatWhitespace();
if (P == End)
return true;
return parseError("Text after end of document");
}
Error takeError() {
assert(Err);
return std::move(*Err);
}
private:
void eatWhitespace() {
while (P != End && (*P == ' ' || *P == '\r' || *P == '\n' || *P == '\t'))
++P;
}
// On invalid syntax, parseX() functions return false and set Err.
bool parseNumber(char First, Value &Out);
bool parseString(std::string &Out);
bool parseUnicode(std::string &Out);
bool parseError(const char *Msg); // always returns false
char next() { return P == End ? 0 : *P++; }
char peek() { return P == End ? 0 : *P; }
static bool isNumber(char C) {
return C == '0' || C == '1' || C == '2' || C == '3' || C == '4' ||
C == '5' || C == '6' || C == '7' || C == '8' || C == '9' ||
C == 'e' || C == 'E' || C == '+' || C == '-' || C == '.';
}
Optional<Error> Err;
const char *Start, *P, *End;
};
bool Parser::parseValue(Value &Out) {
eatWhitespace();
if (P == End)
return parseError("Unexpected EOF");
switch (char C = next()) {
// Bare null/true/false are easy - first char identifies them.
case 'n':
Out = nullptr;
return (next() == 'u' && next() == 'l' && next() == 'l') ||
parseError("Invalid JSON value (null?)");
case 't':
Out = true;
return (next() == 'r' && next() == 'u' && next() == 'e') ||
parseError("Invalid JSON value (true?)");
case 'f':
Out = false;
return (next() == 'a' && next() == 'l' && next() == 's' && next() == 'e') ||
parseError("Invalid JSON value (false?)");
case '"': {
std::string S;
if (parseString(S)) {
Out = std::move(S);
return true;
}
return false;
}
case '[': {
Out = Array{};
Array &A = *Out.getAsArray();
eatWhitespace();
if (peek() == ']') {
++P;
return true;
}
for (;;) {
A.emplace_back(nullptr);
if (!parseValue(A.back()))
return false;
eatWhitespace();
switch (next()) {
case ',':
eatWhitespace();
continue;
case ']':
return true;
default:
return parseError("Expected , or ] after array element");
}
}
}
case '{': {
Out = Object{};
Object &O = *Out.getAsObject();
eatWhitespace();
if (peek() == '}') {
++P;
return true;
}
for (;;) {
if (next() != '"')
return parseError("Expected object key");
std::string K;
if (!parseString(K))
return false;
eatWhitespace();
if (next() != ':')
return parseError("Expected : after object key");
eatWhitespace();
if (!parseValue(O[std::move(K)]))
return false;
eatWhitespace();
switch (next()) {
case ',':
eatWhitespace();
continue;
case '}':
return true;
default:
return parseError("Expected , or } after object property");
}
}
}
default:
if (isNumber(C))
return parseNumber(C, Out);
return parseError("Invalid JSON value");
}
}
bool Parser::parseNumber(char First, Value &Out) {
// Read the number into a string. (Must be null-terminated for strto*).
SmallString<24> S;
S.push_back(First);
while (isNumber(peek()))
S.push_back(next());
char *End;
// Try first to parse as integer, and if so preserve full 64 bits.
// strtoll returns long long >= 64 bits, so check it's in range too.
auto I = std::strtoll(S.c_str(), &End, 10);
if (End == S.end() && I >= std::numeric_limits<int64_t>::min() &&
I <= std::numeric_limits<int64_t>::max()) {
Out = int64_t(I);
return true;
}
// If it's not an integer
Out = std::strtod(S.c_str(), &End);
return End == S.end() || parseError("Invalid JSON value (number?)");
}
bool Parser::parseString(std::string &Out) {
// leading quote was already consumed.
for (char C = next(); C != '"'; C = next()) {
if (LLVM_UNLIKELY(P == End))
return parseError("Unterminated string");
if (LLVM_UNLIKELY((C & 0x1f) == C))
return parseError("Control character in string");
if (LLVM_LIKELY(C != '\\')) {
Out.push_back(C);
continue;
}
// Handle escape sequence.
switch (C = next()) {
case '"':
case '\\':
case '/':
Out.push_back(C);
break;
case 'b':
Out.push_back('\b');
break;
case 'f':
Out.push_back('\f');
break;
case 'n':
Out.push_back('\n');
break;
case 'r':
Out.push_back('\r');
break;
case 't':
Out.push_back('\t');
break;
case 'u':
if (!parseUnicode(Out))
return false;
break;
default:
return parseError("Invalid escape sequence");
}
}
return true;
}
static void encodeUtf8(uint32_t Rune, std::string &Out) {
if (Rune < 0x80) {
Out.push_back(Rune & 0x7F);
} else if (Rune < 0x800) {
uint8_t FirstByte = 0xC0 | ((Rune & 0x7C0) >> 6);
uint8_t SecondByte = 0x80 | (Rune & 0x3F);
Out.push_back(FirstByte);
Out.push_back(SecondByte);
} else if (Rune < 0x10000) {
uint8_t FirstByte = 0xE0 | ((Rune & 0xF000) >> 12);
uint8_t SecondByte = 0x80 | ((Rune & 0xFC0) >> 6);
uint8_t ThirdByte = 0x80 | (Rune & 0x3F);
Out.push_back(FirstByte);
Out.push_back(SecondByte);
Out.push_back(ThirdByte);
} else if (Rune < 0x110000) {
uint8_t FirstByte = 0xF0 | ((Rune & 0x1F0000) >> 18);
uint8_t SecondByte = 0x80 | ((Rune & 0x3F000) >> 12);
uint8_t ThirdByte = 0x80 | ((Rune & 0xFC0) >> 6);
uint8_t FourthByte = 0x80 | (Rune & 0x3F);
Out.push_back(FirstByte);
Out.push_back(SecondByte);
Out.push_back(ThirdByte);
Out.push_back(FourthByte);
} else {
llvm_unreachable("Invalid codepoint");
}
}
// Parse a UTF-16 \uNNNN escape sequence. "\u" has already been consumed.
// May parse several sequential escapes to ensure proper surrogate handling.
// We do not use ConvertUTF.h, it can't accept and replace unpaired surrogates.
// These are invalid Unicode but valid JSON (RFC 8259, section 8.2).
bool Parser::parseUnicode(std::string &Out) {
// Invalid UTF is not a JSON error (RFC 8529ยง8.2). It gets replaced by U+FFFD.
auto Invalid = [&] { Out.append(/* UTF-8 */ {'\xef', '\xbf', '\xbd'}); };
// Decodes 4 hex digits from the stream into Out, returns false on error.
auto Parse4Hex = [this](uint16_t &Out) -> bool {
Out = 0;
char Bytes[] = {next(), next(), next(), next()};
for (unsigned char C : Bytes) {
if (!std::isxdigit(C))
return parseError("Invalid \\u escape sequence");
Out <<= 4;
Out |= (C > '9') ? (C & ~0x20) - 'A' + 10 : (C - '0');
}
return true;
};
uint16_t First; // UTF-16 code unit from the first \u escape.
if (!Parse4Hex(First))
return false;
// We loop to allow proper surrogate-pair error handling.
while (true) {
// Case 1: the UTF-16 code unit is already a codepoint in the BMP.
if (LLVM_LIKELY(First < 0xD800 || First >= 0xE000)) {
encodeUtf8(First, Out);
return true;
}
// Case 2: it's an (unpaired) trailing surrogate.
if (LLVM_UNLIKELY(First >= 0xDC00)) {
Invalid();
return true;
}
// Case 3: it's a leading surrogate. We expect a trailing one next.
// Case 3a: there's no trailing \u escape. Don't advance in the stream.
if (LLVM_UNLIKELY(P + 2 > End || *P != '\\' || *(P + 1) != 'u')) {
Invalid(); // Leading surrogate was unpaired.
return true;
}
P += 2;
uint16_t Second;
if (!Parse4Hex(Second))
return false;
// Case 3b: there was another \u escape, but it wasn't a trailing surrogate.
if (LLVM_UNLIKELY(Second < 0xDC00 || Second >= 0xE000)) {
Invalid(); // Leading surrogate was unpaired.
First = Second; // Second escape still needs to be processed.
continue;
}
// Case 3c: a valid surrogate pair encoding an astral codepoint.
encodeUtf8(0x10000 | ((First - 0xD800) << 10) | (Second - 0xDC00), Out);
return true;
}
}
bool Parser::parseError(const char *Msg) {
int Line = 1;
const char *StartOfLine = Start;
for (const char *X = Start; X < P; ++X) {
if (*X == 0x0A) {
++Line;
StartOfLine = X + 1;
}
}
Err.emplace(
llvm::make_unique<ParseError>(Msg, Line, P - StartOfLine, P - Start));
return false;
}
} // namespace
Expected<Value> parse(StringRef JSON) {
Parser P(JSON);
Value E = nullptr;
if (P.checkUTF8())
if (P.parseValue(E))
if (P.assertEnd())
return std::move(E);
return P.takeError();
}
char ParseError::ID = 0;
static std::vector<const Object::value_type *> sortedElements(const Object &O) {
std::vector<const Object::value_type *> Elements;
for (const auto &E : O)
Elements.push_back(&E);
llvm::sort(Elements,
[](const Object::value_type *L, const Object::value_type *R) {
return L->first < R->first;
});
return Elements;
}
bool isUTF8(llvm::StringRef S, size_t *ErrOffset) {
// Fast-path for ASCII, which is valid UTF-8.
if (LLVM_LIKELY(isASCII(S)))
return true;
const UTF8 *Data = reinterpret_cast<const UTF8 *>(S.data()), *Rest = Data;
if (LLVM_LIKELY(isLegalUTF8String(&Rest, Data + S.size())))
return true;
if (ErrOffset)
*ErrOffset = Rest - Data;
return false;
}
std::string fixUTF8(llvm::StringRef S) {
// This isn't particularly efficient, but is only for error-recovery.
std::vector<UTF32> Codepoints(S.size()); // 1 codepoint per byte suffices.
const UTF8 *In8 = reinterpret_cast<const UTF8 *>(S.data());
UTF32 *Out32 = Codepoints.data();
ConvertUTF8toUTF32(&In8, In8 + S.size(), &Out32, Out32 + Codepoints.size(),
lenientConversion);
Codepoints.resize(Out32 - Codepoints.data());
std::string Res(4 * Codepoints.size(), 0); // 4 bytes per codepoint suffice
const UTF32 *In32 = Codepoints.data();
UTF8 *Out8 = reinterpret_cast<UTF8 *>(&Res[0]);
ConvertUTF32toUTF8(&In32, In32 + Codepoints.size(), &Out8, Out8 + Res.size(),
strictConversion);
Res.resize(reinterpret_cast<char *>(Out8) - Res.data());
return Res;
}
} // namespace json
} // namespace llvm
static void quote(llvm::raw_ostream &OS, llvm::StringRef S) {
OS << '\"';
for (unsigned char C : S) {
if (C == 0x22 || C == 0x5C)
OS << '\\';
if (C >= 0x20) {
OS << C;
continue;
}
OS << '\\';
switch (C) {
// A few characters are common enough to make short escapes worthwhile.
case '\t':
OS << 't';
break;
case '\n':
OS << 'n';
break;
case '\r':
OS << 'r';
break;
default:
OS << 'u';
llvm::write_hex(OS, C, llvm::HexPrintStyle::Lower, 4);
break;
}
}
OS << '\"';
}
enum IndenterAction {
Indent,
Outdent,
Newline,
Space,
};
// Prints JSON. The indenter can be used to control formatting.
template <typename Indenter>
void llvm::json::Value::print(raw_ostream &OS, const Indenter &I) const {
switch (Type) {
case T_Null:
OS << "null";
break;
case T_Boolean:
OS << (as<bool>() ? "true" : "false");
break;
case T_Double:
OS << format("%.*g", std::numeric_limits<double>::max_digits10,
as<double>());
break;
case T_Integer:
OS << as<int64_t>();
break;
case T_StringRef:
quote(OS, as<StringRef>());
break;
case T_String:
quote(OS, as<std::string>());
break;
case T_Object: {
bool Comma = false;
OS << '{';
I(Indent);
for (const auto *P : sortedElements(as<json::Object>())) {
if (Comma)
OS << ',';
Comma = true;
I(Newline);
quote(OS, P->first);
OS << ':';
I(Space);
P->second.print(OS, I);
}
I(Outdent);
if (Comma)
I(Newline);
OS << '}';
break;
}
case T_Array: {
bool Comma = false;
OS << '[';
I(Indent);
for (const auto &E : as<json::Array>()) {
if (Comma)
OS << ',';
Comma = true;
I(Newline);
E.print(OS, I);
}
I(Outdent);
if (Comma)
I(Newline);
OS << ']';
break;
}
}
}
void llvm::format_provider<llvm::json::Value>::format(
const llvm::json::Value &E, raw_ostream &OS, StringRef Options) {
if (Options.empty()) {
OS << E;
return;
}
unsigned IndentAmount = 0;
if (Options.getAsInteger(/*Radix=*/10, IndentAmount))
llvm_unreachable("json::Value format options should be an integer");
unsigned IndentLevel = 0;
E.print(OS, [&](IndenterAction A) {
switch (A) {
case Newline:
OS << '\n';
OS.indent(IndentLevel);
break;
case Space:
OS << ' ';
break;
case Indent:
IndentLevel += IndentAmount;
break;
case Outdent:
IndentLevel -= IndentAmount;
break;
};
});
}
llvm::raw_ostream &llvm::json::operator<<(raw_ostream &OS, const Value &E) {
E.print(OS, [](IndenterAction A) { /*ignore*/ });
return OS;
}