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/*
* Copyright (c) 2014-present, Facebook, Inc.
*
* This source code is licensed under the MIT license found in the
* LICENSE file in the root directory of this source tree.
*/
#pragma once
#include <assert.h>
#include <functional>
#include <iostream>
#include <memory>
#include <vector>
namespace ATDWriter {
struct ATDWriterOptions {
bool useYojson;
bool prettifyJson;
};
// Symbols to be stacked
enum Symbol { SARRAY, STUPLE, SOBJECT, SVARIANT, STAG };
// whether the container has a {maximum,exact} size
enum ContainerSizeKind {
CSKNONE, // no size info
CSKEXACT, // the container expects exactly this number of items
CSKMAX // the container expects at most this number of items
};
// Main class for writing ATD-like data
// - In NDEBUG mode this class is only a wrapper around an ATDEmitter
// - In DEBUG mode it acts as a validator: asserts will fire if the events do
// not correspond to a well-formed ATD/JSON value
template <class ATDEmitter>
class GenWriter {
protected:
ATDEmitter emitter_;
private:
#ifdef DEBUG
// State of the automaton
std::vector<enum Symbol> stack_;
// Objects want tagged values
static bool needsTag(enum Symbol s) { return s == SOBJECT; }
// How many elements are expected in the current container
std::vector<int> containerSize_;
std::vector<enum ContainerSizeKind> containerSizeKind_;
#endif
void enterValue() {
#ifdef DEBUG
if (stack_.empty()) {
return;
}
assert(!needsTag(stack_.back()));
#endif
}
void leaveValue() {
#ifdef DEBUG
switch (containerSizeKind_.back()) {
case CSKEXACT:
case CSKMAX:
containerSize_.back() -= 1;
break;
case CSKNONE:
break;
}
if (stack_.empty()) {
return;
}
if (stack_.back() == STAG) {
stack_.pop_back();
assert(needsTag(stack_.back()));
}
#endif
}
void emitValue() {
enterValue();
leaveValue();
}
void enterContainer(enum Symbol s,
enum ContainerSizeKind csk = CSKNONE,
int numElems = 0) {
#ifdef DEBUG
enterValue();
stack_.push_back(s);
containerSizeKind_.push_back(csk);
switch (csk) {
case CSKEXACT:
case CSKMAX:
containerSize_.push_back(numElems);
break;
case CSKNONE:
break;
}
#endif
}
void leaveContainer(enum Symbol s) {
#ifdef DEBUG
assert(stack_.back() == s);
stack_.pop_back();
switch (containerSizeKind_.back()) {
case CSKEXACT:
assert(containerSize_.back() == 0);
case CSKMAX:
assert(!containerSize_.empty());
assert(containerSize_.back() >= 0);
containerSize_.pop_back();
break;
case CSKNONE:
break;
}
containerSizeKind_.pop_back();
leaveValue();
#endif
}
public:
GenWriter(ATDEmitter emitter) : emitter_(emitter) {
#ifdef DEBUG
containerSizeKind_.push_back(CSKNONE);
#endif
}
~GenWriter() {
#ifdef DEBUG
assert(stack_.empty());
assert(containerSizeKind_.size() == 1);
assert(containerSizeKind_.back() == CSKNONE);
#endif
emitter_.emitEOF();
}
void emitNull() {
emitValue();
emitter_.emitNull();
}
void emitBoolean(bool val) {
emitValue();
emitter_.emitBoolean(val);
}
void emitInteger(int64_t val) {
emitValue();
emitter_.emitInteger(val);
}
void emitFloat(float val) {
emitValue();
emitter_.emitFloat(val);
}
void emitString(const std::string &val) {
emitValue();
emitter_.emitString(val);
}
void emitTag(const std::string &val) {
#ifdef DEBUG
assert(needsTag(stack_.back()));
stack_.push_back(STAG);
#endif
emitter_.emitTag(val);
}
void enterArray(int numElems) {
enterContainer(SARRAY, CSKEXACT, numElems);
emitter_.enterArray(numElems);
}
void enterArray() {
enterContainer(SARRAY);
emitter_.enterArray();
}
void leaveArray() {
leaveContainer(SARRAY);
emitter_.leaveArray();
}
void enterObject(int numElems) {
enterContainer(SOBJECT, CSKMAX, numElems);
emitter_.enterObject(numElems);
}
void enterObject() {
enterContainer(SOBJECT);
emitter_.enterObject();
}
void leaveObject() {
leaveContainer(SOBJECT);
emitter_.leaveObject();
}
void enterTuple(int numElems) {
enterContainer(STUPLE, CSKEXACT, numElems);
emitter_.enterTuple(numElems);
}
void enterTuple() {
enterContainer(STUPLE);
emitter_.enterTuple();
}
void leaveTuple() {
leaveContainer(STUPLE);
emitter_.leaveTuple();
}
void enterVariant(const std::string &tag, bool hasArg = true) {
// variants have at most one value, so we can safely use hasArg
// as the number of arguments
enterContainer(SVARIANT, CSKEXACT, hasArg);
emitter_.enterVariant();
emitter_.emitVariantTag(tag, hasArg);
}
void leaveVariant() {
leaveContainer(SVARIANT);
emitter_.leaveVariant();
}
void emitSimpleVariant(const std::string &tag) {
if (emitter_.shouldSimpleVariantsBeEmittedAsStrings) {
emitString(tag);
} else {
enterVariant(tag, false);
leaveVariant();
}
}
// convenient methods
void emitFlag(const std::string &tag, bool val) {
if (val) {
emitTag(tag);
emitBoolean(true);
}
}
// convenient classes for automatically closing containers using C++ scoping
class ArrayScope {
GenWriter &f_;
public:
ArrayScope(GenWriter &f, int size) : f_(f) { f_.enterArray(size); }
ArrayScope(GenWriter &f) : f_(f) { f_.enterArray(); }
~ArrayScope() { f_.leaveArray(); }
};
class ObjectScope {
GenWriter &f_;
public:
ObjectScope(GenWriter &f, int size) : f_(f) { f_.enterObject(size); }
ObjectScope(GenWriter &f) : f_(f) { f_.enterObject(); }
~ObjectScope() { f_.leaveObject(); }
};
class TupleScope {
GenWriter &f_;
public:
TupleScope(GenWriter &f, int size) : f_(f) { f_.enterTuple(size); }
TupleScope(GenWriter &f) : f_(f) { f_.enterTuple(); }
~TupleScope() { f_.leaveTuple(); }
};
class VariantScope {
GenWriter &f_;
public:
VariantScope(GenWriter &f, const std::string &tag) : f_(f) {
f_.enterVariant(tag, true);
}
~VariantScope() { f_.leaveVariant(); }
};
};
// Configure GenWriter for Yojson / Json textual outputs
template <class OStream = std::ostream>
class JsonEmitter {
const char *QUOTE = "\"";
const char *COMMA = ",";
const char *TAB = " ";
const char *NEWLINE = "\n";
const char *COLON = ":";
const char *COLONWITHSPACES = " : ";
const char *COMMAWITHSPACES = " , ";
const char *NULLSTR = "null";
const char *FALSESTR = "false";
const char *TRUESTR = "true";
const char LBRACKET = '[';
const char RBRACKET = ']';
const char LBRACE = '{';
const char RBRACE = '}';
const char LPAREN = '(';
const char RPAREN = ')';
const char LANGLE = '<';
const char RANGLE = '>';
private:
OStream &os_;
const ATDWriterOptions options_;
unsigned indentLevel_;
bool nextElementNeedsNewLine_;
bool previousElementNeedsComma_;
bool previousElementIsVariantTag_;
public:
bool shouldSimpleVariantsBeEmittedAsStrings;
JsonEmitter(OStream &os, const ATDWriterOptions opts)
: os_(os),
options_(opts),
indentLevel_(0),
nextElementNeedsNewLine_(false),
previousElementNeedsComma_(false),
previousElementIsVariantTag_(false),
shouldSimpleVariantsBeEmittedAsStrings(!opts.useYojson) {}
void tab() {
if (previousElementIsVariantTag_) {
if (options_.prettifyJson) {
os_ << (options_.useYojson ? COLONWITHSPACES : COMMAWITHSPACES);
} else {
os_ << (options_.useYojson ? COLON : COMMA);
}
} else if (previousElementNeedsComma_) {
os_ << COMMA;
}
if (nextElementNeedsNewLine_ && options_.prettifyJson) {
os_ << NEWLINE;
for (size_t i = 0; i < indentLevel_; i++) {
os_ << TAB;
}
}
}
private:
// TODO: unicode and other control chars
void write_escaped(const std::string &val) {
for (std::string::const_iterator i = val.begin(), e = val.end(); i != e;
i++) {
char x = *i;
switch (x) {
case '\\':
os_ << "\\\\";
break;
case '"':
os_ << "\\\"";
break;
case '\n':
os_ << "\\n";
break;
case '\t':
os_ << "\\t";
break;
case '\b':
os_ << "\\b";
break;
case '\f':
os_ << "\\f";
break;
case '\r':
os_ << "\\r";
break;
default:
os_ << x;
break;
}
}
}
void enterContainer(char c) {
tab();
os_ << c;
indentLevel_++;
previousElementNeedsComma_ = false;
nextElementNeedsNewLine_ = true;
previousElementIsVariantTag_ = false;
}
void leaveContainer(char c) {
indentLevel_--;
// suppress the last comma or variant separator
previousElementNeedsComma_ = false;
previousElementIsVariantTag_ = false;
tab();
os_ << c;
previousElementNeedsComma_ = true;
nextElementNeedsNewLine_ = true;
}
public:
void emitEOF() { os_ << NEWLINE; }
void emitNull() {
tab();
os_ << NULLSTR;
previousElementNeedsComma_ = true;
nextElementNeedsNewLine_ = true;
previousElementIsVariantTag_ = false;
}
void emitBoolean(bool val) {
tab();
os_ << (val ? TRUESTR : FALSESTR);
previousElementNeedsComma_ = true;
nextElementNeedsNewLine_ = true;
previousElementIsVariantTag_ = false;
}
void emitInteger(int64_t val) {
tab();
os_ << val;
previousElementNeedsComma_ = true;
nextElementNeedsNewLine_ = true;
previousElementIsVariantTag_ = false;
}
void emitString(const std::string &val) {
tab();
os_ << QUOTE;
write_escaped(val);
os_ << QUOTE;
previousElementNeedsComma_ = true;
nextElementNeedsNewLine_ = true;
previousElementIsVariantTag_ = false;
}
void emitTag(const std::string &val) {
tab();
os_ << QUOTE;
write_escaped(val);
os_ << QUOTE;
if (options_.prettifyJson) {
os_ << COLONWITHSPACES;
} else {
os_ << COLON;
}
previousElementNeedsComma_ = false;
nextElementNeedsNewLine_ = false;
previousElementIsVariantTag_ = false;
}
void emitVariantTag(const std::string &val, bool hasArgs) {
tab();
os_ << QUOTE;
write_escaped(val);
os_ << QUOTE;
previousElementNeedsComma_ = false;
nextElementNeedsNewLine_ = false;
previousElementIsVariantTag_ = true;
}
void enterArray() { enterContainer(LBRACKET); }
void enterArray(int size) { enterArray(); }
void leaveArray() { leaveContainer(RBRACKET); }
void enterObject() { enterContainer(LBRACE); }
void enterObject(int size) { enterObject(); }
void leaveObject() { leaveContainer(RBRACE); }
void enterTuple() { enterContainer(options_.useYojson ? LPAREN : LBRACKET); }
void enterTuple(int size) { enterTuple(); }
void leaveTuple() { leaveContainer(options_.useYojson ? RPAREN : RBRACKET); }
void enterVariant() {
enterContainer(options_.useYojson ? LANGLE : LBRACKET);
// cancel indent
indentLevel_--;
nextElementNeedsNewLine_ = false;
}
void leaveVariant() {
nextElementNeedsNewLine_ = false;
leaveContainer(options_.useYojson ? RANGLE : RBRACKET);
indentLevel_++;
}
};
const uint8_t bool_tag = 0;
const uint8_t int8_tag = 1;
const uint8_t int16_tag = 2;
const uint8_t int32_tag = 3;
const uint8_t int64_tag = 4;
const uint8_t float64_tag = 12;
const uint8_t uvint_tag = 16;
const uint8_t svint_tag = 17;
const uint8_t string_tag = 18;
const uint8_t ARRAY_tag = 19;
const uint8_t TUPLE_tag = 20;
const uint8_t RECORD_tag = 21;
const uint8_t NUM_VARIANT_tag = 22;
const uint8_t VARIANT_tag = 23;
const uint8_t unit_tag = 24;
const uint8_t TABLE_tag = 25;
const uint8_t SHARED_tag = 26;
const int SIZE_NOT_NEEDED = -1;
// Configure GenWriter for Biniou binary output
template <class OStream = std::ostream>
class BiniouEmitter {
private:
OStream &os_;
// Opened container, writing in progress.
struct ATDContainer {
uint8_t tag;
int size;
int count;
ATDContainer(uint8_t tag, int size) : tag(tag), size(size), count(0) {}
};
// The full stack of opened containers
std::vector<ATDContainer> atdContainers;
public:
const bool shouldSimpleVariantsBeEmittedAsStrings = false;
BiniouEmitter(OStream &os) : os_(os) {}
private:
bool isValueTagNeeded() {
if (!atdContainers.empty()) {
const ATDContainer &obj = atdContainers.back();
return obj.tag != ARRAY_tag || obj.count == 0;
}
return true;
}
void markWrite() {
if (!atdContainers.empty()) {
atdContainers.back().count++;
}
}
void enterContainer(uint8_t tag, int size) {
bool needTag = isValueTagNeeded();
atdContainers.emplace_back(tag, size);
writeValueTag(os_, needTag, tag);
if (size != SIZE_NOT_NEEDED) {
writeUvint(os_, size);
}
}
void leaveContainer() {
atdContainers.pop_back();
markWrite();
}
// string hash algorithm from the biniou spec
static uint32_t biniou_hash(const std::string &str) {
uint32_t hash = 0;
for (const char &c : str) {
hash = 223 * hash + c;
}
hash %= 1 << 31;
return hash;
}
static void write8(OStream &os, uint8_t c) { os.write((const char *)&c, 1); }
static void write32(OStream &os, int32_t x) {
write8(os, x >> 24);
write8(os, x >> 16);
write8(os, x >> 8);
write8(os, x);
}
static void writeUvint(OStream &os, uint64_t x) {
while (x > 127) {
write8(os, x | 128);
x >>= 7;
}
write8(os, (uint8_t)x);
}
static void writeSvint(OStream &os, int64_t x) {
if (x >= 0) {
uint64_t t = x;
t = t * 2;
writeUvint(os, t);
} else {
uint64_t t = -x;
t = t * 2 - 1;
writeUvint(os, t);
}
}
static void writeValueTag(OStream &os, bool needTag, uint8_t tag) {
if (needTag) {
write8(os, tag);
}
}
void emitDummyRecordField() {
emitTag("!!DUMMY!!");
markWrite();
// unit is the smallest value (2 bytes)
write8(os_, unit_tag);
write8(os_, 0);
}
public:
void emitEOF() {}
void emitBoolean(bool val) {
bool needTag = isValueTagNeeded();
markWrite();
writeValueTag(os_, needTag, bool_tag);
write8(os_, val);
}
void emitInteger(int64_t val) {
bool needTag = isValueTagNeeded();
markWrite();
writeValueTag(os_, needTag, svint_tag);
writeSvint(os_, val);
}
void emitString(const std::string &val) {
bool needTag = isValueTagNeeded();
markWrite();
writeValueTag(os_, needTag, string_tag);
writeUvint(os_, val.length());
for (const char &c : val) {
write8(os_, c);
}
}
void emitTag(const std::string &val) {
int32_t hash = biniou_hash(val);
// set first bit of hash
hash |= 1 << 31;
markWrite();
write32(os_, hash);
}
void emitVariantTag(const std::string &val, bool hasArg) {
int32_t hash = biniou_hash(val);
// set first bit of hash if the variant has an argument
if (hasArg) {
hash |= 1 << 31;
}
markWrite();
write32(os_, hash);
}
void enterArray(int size) { enterContainer(ARRAY_tag, size); }
// unsupported:
// void enterArray() { enterContainer(ARRAY_tag); }
void leaveArray() { leaveContainer(); }
void enterObject(int size) { enterContainer(RECORD_tag, size); }
// unsupported:
// void enterObject() { enterContainer(RECORD_tag); }
void leaveObject() {
const ATDContainer &obj = atdContainers.back();
// Container's size was already written -> must fill in for missing
// records.
for (int i = obj.count / 2; i < obj.size; i++) {
emitDummyRecordField();
}
leaveContainer();
}
void enterTuple(int size) { enterContainer(TUPLE_tag, size); }
// unsupported:
// void enterTuple() { enterContainer(TUPLE_tag); }
void leaveTuple() { leaveContainer(); }
void enterVariant() { enterContainer(VARIANT_tag, SIZE_NOT_NEEDED); }
void leaveVariant() { leaveContainer(); }
};
// The full class for JSON and YOJSON writing
template <class OStream = std::ostream>
class JsonWriter : public GenWriter<JsonEmitter<OStream>> {
typedef JsonEmitter<OStream> Emitter;
public:
JsonWriter(OStream &os, const ATDWriterOptions opts)
: GenWriter<Emitter>(Emitter(os, opts)) {}
};
// The full class for biniou writing
template <class OStream>
class BiniouWriter : public GenWriter<BiniouEmitter<OStream>> {
typedef BiniouEmitter<OStream> Emitter;
public:
BiniouWriter(OStream &os) : GenWriter<Emitter>(Emitter(os)) {}
BiniouWriter(OStream &os, const ATDWriterOptions opts)
: GenWriter<Emitter>(Emitter(os)) {}
};
} // namespace ATDWriter