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rocksdb/utilities/document/json_document.cc

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16 KiB

// Copyright (c) 2013, Facebook, Inc. All rights reserved.
// This source code is licensed under the BSD-style license found in the
// LICENSE file in the root directory of this source tree. An additional grant
// of patent rights can be found in the PATENTS file in the same directory.
#ifndef ROCKSDB_LITE
#include "utilities/json_document.h"
#include <cassert>
#include <string>
#include <map>
#include <vector>
#include "third-party/rapidjson/reader.h"
#include "util/coding.h"
namespace rocksdb {
JSONDocument::JSONDocument() : type_(kNull) {}
JSONDocument::JSONDocument(bool b) : type_(kBool) { data_.b = b; }
JSONDocument::JSONDocument(double d) : type_(kDouble) { data_.d = d; }
JSONDocument::JSONDocument(int64_t i) : type_(kInt64) { data_.i = i; }
JSONDocument::JSONDocument(const std::string& s) : type_(kString) {
new (&data_.s) std::string(s);
}
JSONDocument::JSONDocument(const char* s) : type_(kString) {
new (&data_.s) std::string(s);
}
JSONDocument::JSONDocument(Type type) : type_(type) {
// TODO(icanadi) make all of this better by using templates
switch (type) {
case kNull:
break;
case kObject:
new (&data_.o) Object;
break;
case kBool:
data_.b = false;
break;
case kDouble:
data_.d = 0.0;
break;
case kArray:
new (&data_.a) Array;
break;
case kInt64:
data_.i = 0;
break;
case kString:
new (&data_.s) std::string();
break;
default:
assert(false);
}
}
JSONDocument::JSONDocument(const JSONDocument& json_document)
: JSONDocument(json_document.type_) {
switch (json_document.type_) {
case kNull:
break;
case kArray:
data_.a.reserve(json_document.data_.a.size());
for (const auto& iter : json_document.data_.a) {
// deep copy
data_.a.push_back(new JSONDocument(*iter));
}
break;
case kBool:
data_.b = json_document.data_.b;
break;
case kDouble:
data_.d = json_document.data_.d;
break;
case kInt64:
data_.i = json_document.data_.i;
break;
case kObject: {
for (const auto& iter : json_document.data_.o) {
// deep copy
data_.o.insert({iter.first, new JSONDocument(*iter.second)});
}
break;
}
case kString:
data_.s = json_document.data_.s;
break;
default:
assert(false);
}
}
JSONDocument::~JSONDocument() {
switch (type_) {
case kObject:
for (auto iter : data_.o) {
delete iter.second;
}
(&data_.o)->~Object();
break;
case kArray:
for (auto iter : data_.a) {
delete iter;
}
(&data_.a)->~Array();
break;
case kString:
using std::string;
(&data_.s)->~string();
break;
default:
// we're cool, no need for destructors for others
break;
}
}
JSONDocument::Type JSONDocument::type() const { return type_; }
bool JSONDocument::Contains(const std::string& key) const {
assert(type_ == kObject);
auto iter = data_.o.find(key);
return iter != data_.o.end();
}
const JSONDocument* JSONDocument::Get(const std::string& key) const {
assert(type_ == kObject);
auto iter = data_.o.find(key);
if (iter == data_.o.end()) {
return nullptr;
}
return iter->second;
}
JSONDocument& JSONDocument::operator[](const std::string& key) {
assert(type_ == kObject);
auto iter = data_.o.find(key);
assert(iter != data_.o.end());
return *(iter->second);
}
const JSONDocument& JSONDocument::operator[](const std::string& key) const {
assert(type_ == kObject);
auto iter = data_.o.find(key);
assert(iter != data_.o.end());
return *(iter->second);
}
JSONDocument* JSONDocument::Set(const std::string& key, const JSONDocument& value) {
assert(type_ == kObject);
auto itr = data_.o.find(key);
if (itr == data_.o.end()) {
// insert
data_.o.insert({key, new JSONDocument(value)});
} else {
// overwrite
delete itr->second;
itr->second = new JSONDocument(value);
}
return this;
}
size_t JSONDocument::Count() const {
assert(type_ == kArray || type_ == kObject);
if (type_ == kArray) {
return data_.a.size();
} else if (type_ == kObject) {
return data_.o.size();
}
assert(false);
return 0;
}
const JSONDocument* JSONDocument::GetFromArray(size_t i) const {
assert(type_ == kArray);
return data_.a[i];
}
JSONDocument& JSONDocument::operator[](size_t i) {
assert(type_ == kArray && i < data_.a.size());
return *data_.a[i];
}
const JSONDocument& JSONDocument::operator[](size_t i) const {
assert(type_ == kArray && i < data_.a.size());
return *data_.a[i];
}
JSONDocument* JSONDocument::SetInArray(size_t i, const JSONDocument& value) {
assert(IsArray() && i < data_.a.size());
delete data_.a[i];
data_.a[i] = new JSONDocument(value);
return this;
}
JSONDocument* JSONDocument::PushBack(const JSONDocument& value) {
assert(IsArray());
data_.a.push_back(new JSONDocument(value));
return this;
}
bool JSONDocument::IsNull() const { return type() == kNull; }
bool JSONDocument::IsArray() const { return type() == kArray; }
bool JSONDocument::IsBool() const { return type() == kBool; }
bool JSONDocument::IsDouble() const { return type() == kDouble; }
bool JSONDocument::IsInt64() const { return type() == kInt64; }
bool JSONDocument::IsObject() const { return type() == kObject; }
bool JSONDocument::IsString() const { return type() == kString; }
bool JSONDocument::GetBool() const {
assert(IsBool());
return data_.b;
}
double JSONDocument::GetDouble() const {
assert(IsDouble());
return data_.d;
}
int64_t JSONDocument::GetInt64() const {
assert(IsInt64());
return data_.i;
}
const std::string& JSONDocument::GetString() const {
assert(IsString());
return data_.s;
}
bool JSONDocument::operator==(const JSONDocument& rhs) const {
if (type_ != rhs.type_) {
return false;
}
switch (type_) {
case kNull:
return true; // null == null
case kArray:
if (data_.a.size() != rhs.data_.a.size()) {
return false;
}
for (size_t i = 0; i < data_.a.size(); ++i) {
if (!(*data_.a[i] == *rhs.data_.a[i])) {
return false;
}
}
return true;
case kBool:
return data_.b == rhs.data_.b;
case kDouble:
return data_.d == rhs.data_.d;
case kInt64:
return data_.i == rhs.data_.i;
case kObject:
if (data_.o.size() != rhs.data_.o.size()) {
return false;
}
for (const auto& iter : data_.o) {
auto rhs_iter = rhs.data_.o.find(iter.first);
if (rhs_iter == rhs.data_.o.end() ||
!(*(rhs_iter->second) == *iter.second)) {
return false;
}
}
return true;
case kString:
return data_.s == rhs.data_.s;
default:
assert(false);
}
// it can't come to here, but we don't want the compiler to complain
return false;
}
JSONDocument::ItemsIteratorGenerator JSONDocument::Items() const {
assert(type_ == kObject);
return data_.o;
}
// parsing with rapidjson
// TODO(icanadi) (perf) allocate objects with arena
JSONDocument* JSONDocument::ParseJSON(const char* json) {
class JSONDocumentBuilder {
public:
JSONDocumentBuilder() {}
void Null() { stack_.push_back(new JSONDocument()); }
void Bool(bool b) { stack_.push_back(new JSONDocument(b)); }
void Int(int i) { Int64(static_cast<int64_t>(i)); }
void Uint(unsigned i) { Int64(static_cast<int64_t>(i)); }
void Int64(int64_t i) { stack_.push_back(new JSONDocument(i)); }
void Uint64(uint64_t i) { Int64(static_cast<int64_t>(i)); }
void Double(double d) { stack_.push_back(new JSONDocument(d)); }
void String(const char* str, size_t length, bool copy) {
assert(copy);
stack_.push_back(new JSONDocument(std::string(str, length)));
}
void StartObject() { stack_.push_back(new JSONDocument(kObject)); }
void EndObject(size_t member_count) {
assert(stack_.size() > 2 * member_count);
auto object_base_iter = stack_.end() - member_count * 2 - 1;
assert((*object_base_iter)->type_ == kObject);
auto& object_map = (*object_base_iter)->data_.o;
// iter will always be stack_.end() at some point (i.e. will not advance
// past it) because of the way we calculate object_base_iter
for (auto iter = object_base_iter + 1; iter != stack_.end(); iter += 2) {
assert((*iter)->type_ == kString);
object_map.insert({(*iter)->data_.s, *(iter + 1)});
delete *iter;
}
stack_.erase(object_base_iter + 1, stack_.end());
}
void StartArray() { stack_.push_back(new JSONDocument(kArray)); }
void EndArray(size_t element_count) {
assert(stack_.size() > element_count);
auto array_base_iter = stack_.end() - element_count - 1;
assert((*array_base_iter)->type_ == kArray);
(*array_base_iter)->data_.a.assign(array_base_iter + 1, stack_.end());
stack_.erase(array_base_iter + 1, stack_.end());
}
JSONDocument* GetDocument() {
if (stack_.size() != 1) {
return nullptr;
}
return stack_.back();
}
void DeleteAllDocumentsOnStack() {
for (auto document : stack_) {
delete document;
}
stack_.clear();
}
private:
std::vector<JSONDocument*> stack_;
};
rapidjson::StringStream stream(json);
rapidjson::Reader reader;
JSONDocumentBuilder handler;
bool ok = reader.Parse<0>(stream, handler);
if (!ok) {
handler.DeleteAllDocumentsOnStack();
return nullptr;
}
auto document = handler.GetDocument();
assert(document != nullptr);
return document;
}
// serialization and deserialization
// format:
// ------
// document ::= header(char) object
// object ::= varint32(n) key_value*(n times)
// key_value ::= string element
// element ::= 0x01 (kNull)
// | 0x02 array (kArray)
// | 0x03 byte (kBool)
// | 0x04 double (kDouble)
// | 0x05 int64 (kInt64)
// | 0x06 object (kObject)
// | 0x07 string (kString)
// array ::= varint32(n) element*(n times)
// TODO(icanadi) evaluate string vs cstring format
// string ::= varint32(n) byte*(n times)
// double ::= 64-bit IEEE 754 floating point (8 bytes)
// int64 ::= 8 bytes, 64-bit signed integer, little endian
namespace {
inline char GetPrefixFromType(JSONDocument::Type type) {
static char types[] = {0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7};
return types[type];
}
inline bool GetNextType(Slice* input, JSONDocument::Type* type) {
if (input->size() == 0) {
return false;
}
static JSONDocument::Type prefixes[] = {
JSONDocument::kNull, JSONDocument::kArray, JSONDocument::kBool,
JSONDocument::kDouble, JSONDocument::kInt64, JSONDocument::kObject,
JSONDocument::kString};
size_t prefix = static_cast<size_t>((*input)[0]);
if (prefix == 0 || prefix >= 0x8) {
return false;
}
input->remove_prefix(1);
*type = prefixes[static_cast<size_t>(prefix - 1)];
return true;
}
// TODO(icanadi): Make sure this works on all platforms we support. Some
// platforms may store double in different binary format (our specification says
// we need IEEE 754)
inline void PutDouble(std::string* dst, double d) {
dst->append(reinterpret_cast<char*>(&d), sizeof(d));
}
bool DecodeDouble(Slice* input, double* d) {
if (input->size() < sizeof(double)) {
return false;
}
memcpy(d, input->data(), sizeof(double));
input->remove_prefix(sizeof(double));
return true;
}
} // namespace
void JSONDocument::Serialize(std::string* dst) const {
// first byte is reserved for header
// currently, header is only version number. that will help us provide
// backwards compatility. we might also store more information here if
// necessary
dst->push_back(kSerializationFormatVersion);
SerializeInternal(dst, false);
}
void JSONDocument::SerializeInternal(std::string* dst, bool type_prefix) const {
if (type_prefix) {
dst->push_back(GetPrefixFromType(type_));
}
switch (type_) {
case kNull:
// just the prefix is all we need
break;
case kArray:
PutVarint32(dst, static_cast<uint32_t>(data_.a.size()));
for (const auto& element : data_.a) {
element->SerializeInternal(dst, true);
}
break;
case kBool:
dst->push_back(static_cast<char>(data_.b));
break;
case kDouble:
PutDouble(dst, data_.d);
break;
case kInt64:
PutFixed64(dst, static_cast<uint64_t>(data_.i));
break;
case kObject: {
PutVarint32(dst, static_cast<uint32_t>(data_.o.size()));
for (const auto& iter : data_.o) {
PutLengthPrefixedSlice(dst, Slice(iter.first));
iter.second->SerializeInternal(dst, true);
}
break;
}
case kString:
PutLengthPrefixedSlice(dst, Slice(data_.s));
break;
default:
assert(false);
}
}
const char JSONDocument::kSerializationFormatVersion = 1;
JSONDocument* JSONDocument::Deserialize(const Slice& src) {
Slice input(src);
if (src.size() == 0) {
return nullptr;
}
char header = input[0];
if (header != kSerializationFormatVersion) {
// don't understand this header (possibly newer version format and we don't
// support downgrade)
return nullptr;
}
input.remove_prefix(1);
auto root = new JSONDocument(kObject);
bool ok = root->DeserializeInternal(&input);
if (!ok || input.size() > 0) {
// parsing failure :(
delete root;
return nullptr;
}
return root;
}
bool JSONDocument::DeserializeInternal(Slice* input) {
switch (type_) {
case kNull:
break;
case kArray: {
uint32_t size;
if (!GetVarint32(input, &size)) {
return false;
}
data_.a.resize(size);
for (size_t i = 0; i < size; ++i) {
Type type;
if (!GetNextType(input, &type)) {
return false;
}
data_.a[i] = new JSONDocument(type);
if (!data_.a[i]->DeserializeInternal(input)) {
return false;
}
}
break;
}
case kBool:
if (input->size() < 1) {
return false;
}
data_.b = static_cast<bool>((*input)[0]);
input->remove_prefix(1);
break;
case kDouble:
if (!DecodeDouble(input, &data_.d)) {
return false;
}
break;
case kInt64: {
uint64_t tmp;
if (!GetFixed64(input, &tmp)) {
return false;
}
data_.i = static_cast<int64_t>(tmp);
break;
}
case kObject: {
uint32_t num_elements;
bool ok = GetVarint32(input, &num_elements);
for (uint32_t i = 0; ok && i < num_elements; ++i) {
Slice key;
ok = GetLengthPrefixedSlice(input, &key);
Type type;
ok = ok && GetNextType(input, &type);
if (ok) {
std::unique_ptr<JSONDocument> value(new JSONDocument(type));
ok = value->DeserializeInternal(input);
if (ok) {
data_.o.insert({key.ToString(), value.get()});
value.release();
}
}
}
if (!ok) {
return false;
}
break;
}
case kString: {
Slice key;
if (!GetLengthPrefixedSlice(input, &key)) {
return false;
}
data_.s = key.ToString();
break;
}
default:
// this is an assert and not a return because DeserializeInternal() will
// always be called with a valid type_. In case there has been data
// corruption, GetNextType() is the function that will detect that and
// return corruption
assert(false);
}
return true;
}
} // namespace rocksdb
#endif // ROCKSDB_LITE