/*
* JsonbToCString
* Converts jsonb value to a C-string.
*
* If 'out' argument is non-null, the resulting C-string is stored inside the
* StringBuffer. The resulting string is always returned.
*
* A typical case for passing the StringInfo in rather than NULL is where the
* caller wants access to the len attribute without having to call strlen, e.g.
* if they are converting it to a text* object.
*/
char *
JsonbToCString(StringInfo out, JsonbSuperHeader in, int estimated_len)
{
bool first = true;
JsonbIterator *it;
int type = 0;
JsonbValue v;
int level = 0;
bool redo_switch = false;
if (out == NULL)
out = makeStringInfo();
enlargeStringInfo(out, (estimated_len >= 0) ? estimated_len : 64);
it = JsonbIteratorInit(in);
while (redo_switch ||
((type = JsonbIteratorNext(&it, &v, false)) != WJB_DONE))
{
redo_switch = false;
switch (type)
{
case WJB_BEGIN_ARRAY:
if (!first)
appendBinaryStringInfo(out, ", ", 2);
first = true;
if (!v.val.array.rawScalar)
appendStringInfoChar(out, '[');
level++;
break;
case WJB_BEGIN_OBJECT:
if (!first)
appendBinaryStringInfo(out, ", ", 2);
first = true;
appendStringInfoCharMacro(out, '{');
level++;
break;
case WJB_KEY:
if (!first)
appendBinaryStringInfo(out, ", ", 2);
first = true;
/* json rules guarantee this is a string */
jsonb_put_escaped_value(out, &v);
appendBinaryStringInfo(out, ": ", 2);
type = JsonbIteratorNext(&it, &v, false);
if (type == WJB_VALUE)
{
first = false;
jsonb_put_escaped_value(out, &v);
}
else
{
Assert(type == WJB_BEGIN_OBJECT || type == WJB_BEGIN_ARRAY);
/*
* We need to rerun the current switch() since we need to
* output the object which we just got from the iterator
* before calling the iterator again.
*/
redo_switch = true;
}
break;
case WJB_ELEM:
if (!first)
appendBinaryStringInfo(out, ", ", 2);
else
first = false;
jsonb_put_escaped_value(out, &v);
break;
case WJB_END_ARRAY:
level--;
if (!v.val.array.rawScalar)
appendStringInfoChar(out, ']');
first = false;
break;
case WJB_END_OBJECT:
level--;
appendStringInfoCharMacro(out, '}');
first = false;
break;
default:
elog(ERROR, "unknown flag of jsonb iterator");
}
}
Assert(level == 0);
return out->data;
}
/*
* common worker for above two functions
*/
static char *
JsonbToCStringWorker(StringInfo out, JsonbContainer *in, int estimated_len, bool indent)
{
bool first = true;
JsonbIterator *it;
JsonbValue v;
JsonbIteratorToken type = WJB_DONE;
int level = 0;
bool redo_switch = false;
/* If we are indenting, don't add a space after a comma */
int ispaces = indent ? 1 : 2;
/*
* Don't indent the very first item. This gets set to the indent flag at
* the bottom of the loop.
*/
bool use_indent = false;
bool raw_scalar = false;
bool last_was_key = false;
if (out == NULL)
out = makeStringInfo();
enlargeStringInfo(out, (estimated_len >= 0) ? estimated_len : 64);
it = JsonbIteratorInit(in);
while (redo_switch ||
((type = JsonbIteratorNext(&it, &v, false)) != WJB_DONE))
{
redo_switch = false;
switch (type)
{
case WJB_BEGIN_ARRAY:
if (!first)
appendBinaryStringInfo(out, ", ", ispaces);
if (!v.val.array.rawScalar)
{
add_indent(out, use_indent && !last_was_key, level);
appendStringInfoCharMacro(out, '[');
}
else
raw_scalar = true;
first = true;
level++;
break;
case WJB_BEGIN_OBJECT:
if (!first)
appendBinaryStringInfo(out, ", ", ispaces);
add_indent(out, use_indent && !last_was_key, level);
appendStringInfoCharMacro(out, '{');
first = true;
level++;
break;
case WJB_KEY:
if (!first)
appendBinaryStringInfo(out, ", ", ispaces);
first = true;
add_indent(out, use_indent, level);
/* json rules guarantee this is a string */
jsonb_put_escaped_value(out, &v);
appendBinaryStringInfo(out, ": ", 2);
type = JsonbIteratorNext(&it, &v, false);
if (type == WJB_VALUE)
{
first = false;
jsonb_put_escaped_value(out, &v);
}
else
{
Assert(type == WJB_BEGIN_OBJECT || type == WJB_BEGIN_ARRAY);
/*
* We need to rerun the current switch() since we need to
* output the object which we just got from the iterator
* before calling the iterator again.
*/
redo_switch = true;
}
break;
case WJB_ELEM:
if (!first)
appendBinaryStringInfo(out, ", ", ispaces);
first = false;
if (!raw_scalar)
add_indent(out, use_indent, level);
jsonb_put_escaped_value(out, &v);
break;
case WJB_END_ARRAY:
level--;
if (!raw_scalar)
{
add_indent(out, use_indent, level);
appendStringInfoCharMacro(out, ']');
}
first = false;
break;
case WJB_END_OBJECT:
level--;
add_indent(out, use_indent, level);
appendStringInfoCharMacro(out, '}');
first = false;
break;
default:
elog(ERROR, "unknown jsonb iterator token type");
}
use_indent = indent;
last_was_key = redo_switch;
}
Assert(level == 0);
return out->data;
}
