plv8_type.cc

/*-------------------------------------------------------------------------
 *
 * plv8_type.cc : Postgres from/to v8 data converters.
 *
 * Copyright (c) 2009-2012, the PLV8JS Development Group.
 *-------------------------------------------------------------------------
 */
#include "plv8.h"

extern "C" {
#if PG_VERSION_NUM >= 90300
#include "access/htup_details.h"
#endif
#include "catalog/pg_type.h"
#include "parser/parse_coerce.h"
#include "utils/array.h"
#include "utils/date.h"
#include "utils/datetime.h"
#include "utils/builtins.h"
#if PG_VERSION_NUM >= 90400
#include "utils/jsonb.h"
#endif
#include "utils/lsyscache.h"
#include "utils/syscache.h"
#include "utils/typcache.h"

#if PG_VERSION_NUM >= 90400
#include "utils/jsonb.h"
#endif
} // extern "C"

//#define CHECK_INTEGER_OVERFLOW

using namespace v8;

static Datum ToScalarDatum(Handle<v8::Value> value, bool *isnull, plv8_type *type);
static Datum ToArrayDatum(Handle<v8::Value> value, bool *isnull, plv8_type *type);
static Datum ToRecordDatum(Handle<v8::Value> value, bool *isnull, plv8_type *type);
static Local<v8::Value> ToScalarValue(Datum datum, bool isnull, plv8_type *type);
static Local<v8::Value> ToArrayValue(Datum datum, bool isnull, plv8_type *type);
static Local<v8::Value> ToRecordValue(Datum datum, bool isnull, plv8_type *type);
static double TimestampTzToEpoch(TimestampTz tm);
static Datum EpochToTimestampTz(double epoch);
static double DateToEpoch(DateADT date);
static Datum EpochToDate(double epoch);

void
plv8_fill_type(plv8_type *type, Oid typid, MemoryContext mcxt)
{
	bool    ispreferred;

	if (!mcxt)
		mcxt = CurrentMemoryContext;

	type->typid = typid;
	type->fn_input.fn_mcxt = type->fn_output.fn_mcxt = mcxt;
	get_type_category_preferred(typid, &type->category, &ispreferred);
	type->is_composite = (type->category == TYPCATEGORY_COMPOSITE);
	get_typlenbyvalalign(typid, &type->len, &type->byval, &type->align);

	if (get_typtype(typid) == TYPTYPE_DOMAIN)
	{
		HeapTuple	tp;
		Form_pg_type typtup;

#if PG_VERSION_NUM < 90100
		tp = SearchSysCache(TYPEOID, ObjectIdGetDatum(typid), 0, 0, 0);
#else
		tp = SearchSysCache1(TYPEOID, ObjectIdGetDatum(typid));
#endif
		if (HeapTupleIsValid(tp))
		{
			/*
			 * Check if the type is the external array types.
			 */
			typtup = (Form_pg_type) GETSTRUCT(tp);
			if (strcmp(NameStr(typtup->typname),
						"plv8_int2array") == 0)
			{
				type->ext_array = kExternalShortArray;
			}
			else if (strcmp(NameStr(typtup->typname),
						"plv8_int4array") == 0)
			{
				type->ext_array = kExternalIntArray;
			}
			else if (strcmp(NameStr(typtup->typname),
						"plv8_float4array") == 0)
			{
				type->ext_array = kExternalFloatArray;
			}
			else if (strcmp(NameStr(typtup->typname),
						"plv8_float8array") == 0)
			{
				type->ext_array = kExternalDoubleArray;
			}

			ReleaseSysCache(tp);
		}
		else
			elog(ERROR, "cache lookup failed for type %d", typid);

		if (type->ext_array)
			return;

		/* If not, do as usual. */
	}

	if (type->category == TYPCATEGORY_ARRAY)
	{
		Oid      elemid = get_element_type(typid);

		if (elemid == InvalidOid)
			ereport(ERROR,
				(errmsg("cannot determine element type of array: %u", typid)));

		type->typid = elemid;
		type->is_composite = (TypeCategory(elemid) == TYPCATEGORY_COMPOSITE);
		get_typlenbyvalalign(type->typid, &type->len, &type->byval, &type->align);
	}
}

/*
 * Return the database type inferred by the JS value type.
 * If none looks appropriate, InvalidOid is returned (currently,
 * objects and arrays are in this case).
 */
Oid
inferred_datum_type(Handle<v8::Value> value)
{
	if (value->IsUndefined() || value->IsNull())
		return TEXTOID;
	if (value->IsBoolean())
		return BOOLOID;
	else if (value->IsInt32())
		return INT4OID;
	else if (value->IsUint32())
		return INT8OID;
	else if (value->IsNumber())
		return FLOAT8OID;
	else if (value->IsString())
		return TEXTOID;
	else if (value->IsDate())
		return TIMESTAMPOID;
/*
	else if (value->IsObject())
	else if (value->IsArray())
*/

	return InvalidOid;
}

static Local<Object>
CreateExternalArray(void *data, plv8_external_array_type array_type,
					int byte_size, Datum datum)
{
	Local<v8::ArrayBuffer> buffer;
	Local<v8::TypedArray> array;

	buffer = v8::ArrayBuffer::New(plv8_isolate, byte_size);
	if (buffer.IsEmpty())
	{
		return Local<Object>();
	}

	switch (array_type)
	{
	case kExternalByteArray:
		array = v8::Int8Array::New(buffer, 0, byte_size);
		break;
	case kExternalUnsignedByteArray:
		array = v8::Uint8Array::New(buffer, 0, byte_size);
		break;
	case kExternalShortArray:
		array = v8::Int16Array::New(buffer, 0, byte_size / sizeof(int16));
		break;
	case kExternalUnsignedShortArray:
		array = v8::Uint16Array::New(buffer, 0, byte_size / sizeof(int16));
		break;
	case kExternalIntArray:
		array = v8::Int32Array::New(buffer, 0, byte_size / sizeof(int32));
		break;
	case kExternalUnsignedIntArray:
		array = v8::Uint32Array::New(buffer, 0, byte_size / sizeof(int32));
		break;
	case kExternalFloatArray:
		array = v8::Float32Array::New(buffer, 0, byte_size / sizeof(float4));
		break;
	case kExternalDoubleArray:
		array = v8::Float64Array::New(buffer, 0, byte_size / sizeof(float8));
		break;
	default:
		throw js_error("unexpected array type");
	}
	array->SetInternalField(0, External::New(plv8_isolate, DatumGetPointer(datum)));
	// FIXME(bnoordhuis) Could create an ArrayBuffer directly from |data|
	// but as it's unclear who owns that memory and what its life span is,
	// let's just copy it over.
	memcpy(buffer->GetContents().Data(), data, byte_size);

	return array;
}

static void *
ExtractExternalArrayDatum(Handle<v8::Value> value)
{
	if (value->IsUndefined() || value->IsNull()) {
		return NULL;
	}

	if (value->IsTypedArray())
	{
		Handle<Object> object = Handle<Object>::Cast(value);
		return Handle<External>::Cast(object->GetInternalField(0))->Value();
	}

	return NULL;
}

Datum
ToDatum(Handle<v8::Value> value, bool *isnull, plv8_type *type)
{
	if (type->category == TYPCATEGORY_ARRAY)
		return ToArrayDatum(value, isnull, type);
	else
		return ToScalarDatum(value, isnull, type);
}

static Datum
ToScalarDatum(Handle<v8::Value> value, bool *isnull, plv8_type *type)
{
	if (type->category == TYPCATEGORY_COMPOSITE)
		return ToRecordDatum(value, isnull, type);

	if (value->IsUndefined() || value->IsNull())
	{
		*isnull = true;
		return (Datum) 0;
	}

	*isnull = false;
	switch (type->typid)
	{
	case OIDOID:
		if (value->IsNumber())
			return ObjectIdGetDatum(value->Uint32Value());
		break;
	case BOOLOID:
		if (value->IsBoolean())
			return BoolGetDatum(value->BooleanValue());
		break;
	case INT2OID:
		if (value->IsNumber())
#ifdef CHECK_INTEGER_OVERFLOW
			return DirectFunctionCall1(int82,
					Int64GetDatum(value->IntegerValue()));
#else
			return Int16GetDatum((int16) value->Int32Value());
#endif
		break;
	case INT4OID:
		if (value->IsNumber())
#ifdef CHECK_INTEGER_OVERFLOW
			return DirectFunctionCall1(int84,
					Int64GetDatum(value->IntegerValue()));
#else
			return Int32GetDatum((int32) value->Int32Value());
#endif
		break;
	case INT8OID:
		if (value->IsNumber())
			return Int64GetDatum((int64) value->IntegerValue());
		break;
	case FLOAT4OID:
		if (value->IsNumber())
			return Float4GetDatum((float4) value->NumberValue());
		break;
	case FLOAT8OID:
		if (value->IsNumber())
			return Float8GetDatum((float8) value->NumberValue());
		break;
	case NUMERICOID:
		if (value->IsNumber())
			return DirectFunctionCall1(float8_numeric,
					Float8GetDatum((float8) value->NumberValue()));
		break;
	case DATEOID:
		if (value->IsDate())
			return EpochToDate(value->NumberValue());
		break;
	case TIMESTAMPOID:
	case TIMESTAMPTZOID:
		if (value->IsDate())
			return EpochToTimestampTz(value->NumberValue());
		break;
	case BYTEAOID:
		{
			if (value->IsUint8Array() || value->IsInt8Array()) {
				v8::Handle<v8::Uint8Array> array = v8::Handle<v8::Uint8Array>::Cast(value);
				void *data = array->Buffer()->GetContents().Data();
				int		len = array->Length();
				size_t		size = len + VARHDRSZ;
				void	   *result = (void *) palloc(size);

				SET_VARSIZE(result, size);
				memcpy(VARDATA(result), data, len);
				return PointerGetDatum(result);
			}

			if (value->IsUint16Array() || value->IsInt16Array()) {
				v8::Handle<v8::Uint16Array> array = v8::Handle<v8::Uint16Array>::Cast(value);
				void *data = array->Buffer()->GetContents().Data();
				int		len = array->Length();
				size_t		size = (len * 2) + VARHDRSZ;
				void	   *result = (void *) palloc(size);

				SET_VARSIZE(result, size);
				memcpy(VARDATA(result), data, len * 2);
				return PointerGetDatum(result);
			}

			if (value->IsUint32Array() || value->IsInt32Array()) {
				v8::Handle<v8::Uint32Array> array = v8::Handle<v8::Uint32Array>::Cast(value);
				void *data = array->Buffer()->GetContents().Data();
				int		len = array->Length();
				size_t		size = (len * 4) + VARHDRSZ;
				void	   *result = (void *) palloc(size);

				SET_VARSIZE(result, size);
				memcpy(VARDATA(result), data, len * 4);
				return PointerGetDatum(result);
			}

			if (value->IsArrayBuffer()) {
				v8::Handle<v8::ArrayBuffer> array = v8::Handle<v8::ArrayBuffer>::Cast(value);
				void *data = array->GetContents().Data();
				int		len = array->ByteLength();
				size_t		size = len + VARHDRSZ;
				void	   *result = (void *) palloc(size);

				SET_VARSIZE(result, size);
				memcpy(VARDATA(result), data, len);
				return PointerGetDatum(result);
			}

			void *datum_p = ExtractExternalArrayDatum(value);

			if (datum_p)
			{
				return PointerGetDatum(datum_p);
			}
		}
#if PG_VERSION_NUM >= 90400
	case JSONBOID:
		if (value->IsObject() || value->IsArray())
		{
			JSONObject JSON;

			Handle<v8::Value> result = JSON.Stringify(value);
			CString str(result);

#if PG_VERSION_NUM < 110000
			// lots of casting, but it ends up working - there is no CStringGetJsonb exposed
			return (Datum) DatumGetJsonb(DirectFunctionCall1(jsonb_in, (Datum) (char *) str));
#else
			return (Datum) DatumGetJsonbP(DirectFunctionCall1(jsonb_in, (Datum) (char *) str));
#endif
		}
		break;
#endif
#if PG_VERSION_NUM >= 90200
	case JSONOID:
		if (value->IsObject() || value->IsArray())
		{
			JSONObject JSON;

			Handle<v8::Value> result = JSON.Stringify(value);
			CString str(result);

			return CStringGetTextDatum(str);
		}
		break;
#endif
	}

	/* Use lexical cast for non-numeric types. */
	CString		str(value);
	Datum		result;

	PG_TRY();
	{
		if (type->fn_input.fn_addr == NULL)
		{
			Oid    input_func;

			getTypeInputInfo(type->typid, &input_func, &type->ioparam);
			fmgr_info_cxt(input_func, &type->fn_input, type->fn_input.fn_mcxt);
		}
		result = InputFunctionCall(&type->fn_input, str, type->ioparam, -1);
	}
	PG_CATCH();
	{
		throw pg_error();
	}
	PG_END_TRY();

	return result;
}

static Datum
ToArrayDatum(Handle<v8::Value> value, bool *isnull, plv8_type *type)
{
	int			length;
	Datum	   *values;
	bool	   *nulls;
	int			ndims[1];
	int			lbs[] = {1};
	ArrayType  *result;

	if (value->IsUndefined() || value->IsNull())
	{
		*isnull = true;
		return (Datum) 0;
	}

	void *datum_p = ExtractExternalArrayDatum(value);
	if (datum_p)
	{
		*isnull = false;
		return PointerGetDatum(datum_p);
	}

	Handle<Array> array(Handle<Array>::Cast(value));
	if (array.IsEmpty() || !array->IsArray())
		throw js_error("value is not an Array");

	length = array->Length();
	values = (Datum *) palloc(sizeof(Datum) * length);
	nulls = (bool *) palloc(sizeof(bool) * length);
	ndims[0] = length;
	for (int i = 0; i < length; i++) {
		if (type->is_composite)
		{
			values[i] = ToRecordDatum(array->Get(i), &nulls[i], type);
		} else {
			values[i] = ToScalarDatum(array->Get(i), &nulls[i], type);
		}
	}

	result = construct_md_array(values, nulls, 1, ndims, lbs,
				type->typid, type->len, type->byval, type->align);
	pfree(values);
	pfree(nulls);

	*isnull = false;
	return PointerGetDatum(result);
}

static Datum
ToRecordDatum(Handle<v8::Value> value, bool *isnull, plv8_type *type)
{
	Datum		result;
	TupleDesc	tupdesc;

	if (value->IsUndefined() || value->IsNull())
	{
		*isnull = true;
		return (Datum) 0;
	}

	PG_TRY();
	{
		tupdesc = lookup_rowtype_tupdesc(type->typid, -1);
	}
	PG_CATCH();
	{
		throw pg_error();
	}
	PG_END_TRY();

	Converter	conv(tupdesc);

	result = conv.ToDatum(value);

	ReleaseTupleDesc(tupdesc);

	*isnull = false;
	return result;
}

Local<v8::Value>
ToValue(Datum datum, bool isnull, plv8_type *type)
{
	if (isnull)
		return Local<v8::Value>::New(plv8_isolate, Null(plv8_isolate));
	else if (type->category == TYPCATEGORY_ARRAY || type->typid == RECORDARRAYOID)
		return ToArrayValue(datum, isnull, type);
	else if (type->category == TYPCATEGORY_COMPOSITE || type->typid == RECORDOID)
		return ToRecordValue(datum, isnull, type);
	else
		return ToScalarValue(datum, isnull, type);
}

static Local<v8::Value>
ToScalarValue(Datum datum, bool isnull, plv8_type *type)
{
	switch (type->typid)
	{
	case OIDOID:
		return Uint32::New(plv8_isolate, DatumGetObjectId(datum));
	case BOOLOID:
		return Boolean::New(plv8_isolate, DatumGetBool(datum));
	case INT2OID:
		return Int32::New(plv8_isolate, DatumGetInt16(datum));
	case INT4OID:
		return Int32::New(plv8_isolate, DatumGetInt32(datum));
	case INT8OID:
		return Number::New(plv8_isolate, DatumGetInt64(datum));
	case FLOAT4OID:
		return Number::New(plv8_isolate, DatumGetFloat4(datum));
	case FLOAT8OID:
		return Number::New(plv8_isolate, DatumGetFloat8(datum));
	case NUMERICOID:
		return Number::New(plv8_isolate, DatumGetFloat8(
			DirectFunctionCall1(numeric_float8, datum)));
	case DATEOID:
		return Date::New(plv8_isolate, DateToEpoch(DatumGetDateADT(datum)));
	case TIMESTAMPOID:
	case TIMESTAMPTZOID:
		return Date::New(plv8_isolate, TimestampTzToEpoch(DatumGetTimestampTz(datum)));
	case TEXTOID:
	case VARCHAROID:
	case BPCHAROID:
	case XMLOID:
	{
		void	   *p = PG_DETOAST_DATUM_PACKED(datum);
		const char *str = VARDATA_ANY(p);
		int			len = VARSIZE_ANY_EXHDR(p);

		Local<String>	result = ToString(str, len);

		if (p != DatumGetPointer(datum))
			pfree(p);	// free if detoasted
		return result;
	}
	case BYTEAOID:
	{
		void	   *p = PG_DETOAST_DATUM_COPY(datum);

		return CreateExternalArray(VARDATA_ANY(p),
								   kExternalUnsignedByteArray,
								   VARSIZE_ANY_EXHDR(p),
								   PointerGetDatum(p));
	}
#if PG_VERSION_NUM >= 90200
	case JSONOID:
	{
		void	   *p = PG_DETOAST_DATUM_PACKED(datum);
		const char *str = VARDATA_ANY(p);
		int			len = VARSIZE_ANY_EXHDR(p);

		Local<v8::Value>	jsonString = ToString(str, len);
		JSONObject JSON;
		Local<v8::Value> result = Local<v8::Value>::New(plv8_isolate, JSON.Parse(jsonString));

		if (p != DatumGetPointer(datum))
			pfree(p);	// free if detoasted
		return result;
	}
#endif
#if PG_VERSION_NUM >= 90400
	case JSONBOID:
	{
		Local<v8::Value>	jsonString = ToString(datum, type);
		JSONObject JSON;
		Local<v8::Value> result = Local<v8::Value>::New(plv8_isolate, JSON.Parse(jsonString));

		return result;
	}
#endif
	default:
		return ToString(datum, type);
	}
}

static Local<v8::Value>
ToArrayValue(Datum datum, bool isnull, plv8_type *type)
{
	Datum	   *values;
	bool	   *nulls;
	int			nelems;

	/*
	 * If we can use an external array, do it instead.
	 */
	if (type->ext_array)
	{
		ArrayType   *array = DatumGetArrayTypePCopy(datum);

		/*
		 * We allow only non-NULL, 1-dim array.
		 */
		if (!ARR_HASNULL(array) && ARR_NDIM(array) <= 1)
		{
			int			data_bytes = ARR_SIZE(array) -
										ARR_OVERHEAD_NONULLS(1);
			return CreateExternalArray(ARR_DATA_PTR(array),
									   type->ext_array,
									   data_bytes,
									   PointerGetDatum(array));
		}

		throw js_error("NULL element, or multi-dimension array not allowed"
						" in external array type");
	}

	deconstruct_array(DatumGetArrayTypeP(datum),
						type->typid, type->len, type->byval, type->align,
						&values, &nulls, &nelems);
	Local<Array>  result = Array::New(plv8_isolate, nelems);
	plv8_type base = { 0 };
	bool    ispreferred;

	base.typid = type->typid;
	if (base.typid == RECORDARRAYOID)
		base.typid = RECORDOID;

	base.fn_input.fn_mcxt = base.fn_output.fn_mcxt = type->fn_input.fn_mcxt;
	get_type_category_preferred(base.typid, &(base.category), &ispreferred);
	get_typlenbyvalalign(base.typid, &(base.len), &(base.byval), &(base.align));

	for (int i = 0; i < nelems; i++)
		result->Set(i, ToValue(values[i], nulls[i], &base));

	pfree(values);
	pfree(nulls);

	return result;
}

static Local<v8::Value>
ToRecordValue(Datum datum, bool isnull, plv8_type *type)
{
	HeapTupleHeader	rec = DatumGetHeapTupleHeader(datum);
	Oid				tupType;
	int32			tupTypmod;
	TupleDesc		tupdesc;
	HeapTupleData	tuple;

	PG_TRY();
	{
		/* Extract type info from the tuple itself */
		tupType = HeapTupleHeaderGetTypeId(rec);
		tupTypmod = HeapTupleHeaderGetTypMod(rec);
		tupdesc = lookup_rowtype_tupdesc(tupType, tupTypmod);
	}
	PG_CATCH();
	{
		throw pg_error();
	}
	PG_END_TRY();

	Converter	conv(tupdesc);

	/* Build a temporary HeapTuple control structure */
	tuple.t_len = HeapTupleHeaderGetDatumLength(rec);
	ItemPointerSetInvalid(&(tuple.t_self));
	tuple.t_tableOid = InvalidOid;
	tuple.t_data = rec;

	Local<v8::Value> result = conv.ToValue(&tuple);

	ReleaseTupleDesc(tupdesc);

	return result;
}

Local<String>
ToString(Datum value, plv8_type *type)
{
	int		encoding = GetDatabaseEncoding();
	char   *str;

	PG_TRY();
	{
		if (type->fn_output.fn_addr == NULL)
		{
			Oid		output_func;
			bool	isvarlen;

			getTypeOutputInfo(type->typid, &output_func, &isvarlen);
			fmgr_info_cxt(output_func, &type->fn_output, type->fn_output.fn_mcxt);
		}
		str = OutputFunctionCall(&type->fn_output, value);
	}
	PG_CATCH();
	{
		throw pg_error();
	}
	PG_END_TRY();

	Local<String>	result =
		encoding == PG_UTF8
			? String::NewFromUtf8(plv8_isolate, str)
			: ToString(str, strlen(str), encoding);
	pfree(str);

	return result;
}

Local<String>
ToString(const char *str, int len, int encoding)
{
	char		   *utf8;

	if (len < 0)
		len = strlen(str);

	PG_TRY();
	{
		utf8 = (char *) pg_do_encoding_conversion(
					(unsigned char *) str, len, encoding, PG_UTF8);
	}
	PG_CATCH();
	{
		throw pg_error();
	}
	PG_END_TRY();

	if (utf8 != str)
		len = strlen(utf8);
	Local<String> result = String::NewFromUtf8(plv8_isolate, utf8, String::kNormalString, len);
	if (utf8 != str)
		pfree(utf8);
	return result;
}

/*
 * Convert utf8 text to database encoded text.
 * The result could be same as utf8 input, or palloc'ed one.
 */
char *
ToCString(const String::Utf8Value &value)
{
	char *str = const_cast<char *>(*value);
	if (str == NULL)
		return NULL;

	int    encoding = GetDatabaseEncoding();
	if (encoding == PG_UTF8)
		return str;

	PG_TRY();
	{
		str = (char *) pg_do_encoding_conversion(
				(unsigned char *) str, strlen(str), PG_UTF8, encoding);
	}
	PG_CATCH();
	{
		throw pg_error();
	}
	PG_END_TRY();

	return str;
}

/*
 * Convert utf8 text to database encoded text.
 * The result is always palloc'ed one.
 */
char *
ToCStringCopy(const String::Utf8Value &value)
{
	char *str;
	const char *utf8 = *value;
	if (utf8 == NULL)
		return NULL;

	PG_TRY();
	{
		int	encoding = GetDatabaseEncoding();
		str = (char *) pg_do_encoding_conversion(
				(unsigned char *) utf8, strlen(utf8), PG_UTF8, encoding);
		if (str == utf8)
			str = pstrdup(utf8);
	}
	PG_CATCH();
	{
		throw pg_error();
	}
	PG_END_TRY();

	return str;
}

/*
 * Since v8 represents a Date object using a double value in msec from unix epoch,
 * we need to shift the epoch and adjust the time unit.
 */
static double
TimestampTzToEpoch(TimestampTz tm)
{
	double		epoch;

	// TODO: check if TIMESTAMP_NOBEGIN or NOEND
#ifdef HAVE_INT64_TIMESTAMP
	epoch = (double) tm / 1000.0;
#else
	epoch = (double) tm * 1000.0;
#endif

	return epoch + (POSTGRES_EPOCH_JDATE - UNIX_EPOCH_JDATE) * 86400000.0;
}

static Datum
EpochToTimestampTz(double epoch)
{
	epoch -= (POSTGRES_EPOCH_JDATE - UNIX_EPOCH_JDATE) * 86400000.0;

#ifdef HAVE_INT64_TIMESTAMP
	return Int64GetDatum((int64) epoch * 1000);
#else
	return Float8GetDatum(epoch / 1000.0);
#endif
}

static double
DateToEpoch(DateADT date)
{
	double		epoch;

	// TODO: check if DATE_NOBEGIN or NOEND
#ifdef HAVE_INT64_TIMESTAMP
	epoch = (double) date * USECS_PER_DAY / 1000.0;
#else
	epoch = (double) date * SECS_PER_DAY * 1000.0;
#endif

	return epoch + (POSTGRES_EPOCH_JDATE - UNIX_EPOCH_JDATE) * 86400000.0;
}

static Datum
EpochToDate(double epoch)
{
	epoch -= (POSTGRES_EPOCH_JDATE - UNIX_EPOCH_JDATE) * 86400000.0;

#ifdef HAVE_INT64_TIMESTAMP
	epoch = (epoch * 1000) / USECS_PER_DAY;
#else
    epoch = (epoch / 1000) / SECS_PER_DAY;
#endif
	PG_RETURN_DATEADT((DateADT) epoch);
}

CString::CString(Handle<v8::Value> value) : m_utf8(value)
{
	m_str = ToCString(m_utf8);
}

CString::~CString()
{
	if (m_str != *m_utf8)
		pfree(m_str);
}

bool CString::toStdString(v8::Handle<v8::Value> value, std::string &out)
{
	if(value.IsEmpty()) return false;
	auto obj = value->ToString();
	String::Utf8Value utf8(obj);
	if(*utf8) {
		out = *utf8;
		return true;
	}
	return false;
}