greenplumn jsonb_util 源码
greenplumn jsonb_util 代码
文件路径：/src/backend/utils/adt/jsonb_util.c
/*-------------------------------------------------------------------------
*
* jsonb_util.c
* converting between Jsonb and JsonbValues, and iterating.
*
* Copyright (c) 2014-2019, PostgreSQL Global Development Group
*
*
* IDENTIFICATION
* src/backend/utils/adt/jsonb_util.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "catalog/pg_collation.h"
#include "common/hashfn.h"
#include "miscadmin.h"
#include "utils/builtins.h"
#include "utils/jsonb.h"
#include "utils/memutils.h"
#include "utils/varlena.h"
/*
* Maximum number of elements in an array (or key/value pairs in an object).
* This is limited by two things: the size of the JEntry array must fit
* in MaxAllocSize, and the number of elements (or pairs) must fit in the bits
* reserved for that in the JsonbContainer.header field.
*
* (The total size of an array's or object's elements is also limited by
* JENTRY_OFFLENMASK, but we're not concerned about that here.)
*/
#define JSONB_MAX_ELEMS (Min(MaxAllocSize / sizeof(JsonbValue), JB_CMASK))
#define JSONB_MAX_PAIRS (Min(MaxAllocSize / sizeof(JsonbPair), JB_CMASK))
static void fillJsonbValue(JsonbContainer *container, int index,
char *base_addr, uint32 offset,
JsonbValue *result);
static bool equalsJsonbScalarValue(JsonbValue *a, JsonbValue *b);
static int compareJsonbScalarValue(JsonbValue *a, JsonbValue *b);
static Jsonb *convertToJsonb(JsonbValue *val);
static void convertJsonbValue(StringInfo buffer, JEntry *header, JsonbValue *val, int level);
static void convertJsonbArray(StringInfo buffer, JEntry *header, JsonbValue *val, int level);
static void convertJsonbObject(StringInfo buffer, JEntry *header, JsonbValue *val, int level);
static void convertJsonbScalar(StringInfo buffer, JEntry *header, JsonbValue *scalarVal);
static int reserveFromBuffer(StringInfo buffer, int len);
static void appendToBuffer(StringInfo buffer, const char *data, int len);
static void copyToBuffer(StringInfo buffer, int offset, const char *data, int len);
static short padBufferToInt(StringInfo buffer);
static JsonbIterator *iteratorFromContainer(JsonbContainer *container, JsonbIterator *parent);
static JsonbIterator *freeAndGetParent(JsonbIterator *it);
static JsonbParseState *pushState(JsonbParseState **pstate);
static void appendKey(JsonbParseState *pstate, JsonbValue *scalarVal);
static void appendValue(JsonbParseState *pstate, JsonbValue *scalarVal);
static void appendElement(JsonbParseState *pstate, JsonbValue *scalarVal);
static int lengthCompareJsonbStringValue(const void *a, const void *b);
static int lengthCompareJsonbPair(const void *a, const void *b, void *arg);
static void uniqueifyJsonbObject(JsonbValue *object);
static JsonbValue *pushJsonbValueScalar(JsonbParseState **pstate,
JsonbIteratorToken seq,
JsonbValue *scalarVal);
/*
* Turn an in-memory JsonbValue into a Jsonb for on-disk storage.
*
* There isn't a JsonbToJsonbValue(), because generally we find it more
* convenient to directly iterate through the Jsonb representation and only
* really convert nested scalar values. JsonbIteratorNext() does this, so that
* clients of the iteration code don't have to directly deal with the binary
* representation (JsonbDeepContains() is a notable exception, although all
* exceptions are internal to this module). In general, functions that accept
* a JsonbValue argument are concerned with the manipulation of scalar values,
* or simple containers of scalar values, where it would be inconvenient to
* deal with a great amount of other state.
*/
Jsonb *
JsonbValueToJsonb(JsonbValue *val)
{
Jsonb *out;
if (IsAJsonbScalar(val))
{
/* Scalar value */
JsonbParseState *pstate = NULL;
JsonbValue *res;
JsonbValue scalarArray;
scalarArray.type = jbvArray;
scalarArray.val.array.rawScalar = true;
scalarArray.val.array.nElems = 1;
pushJsonbValue(&pstate, WJB_BEGIN_ARRAY, &scalarArray);
pushJsonbValue(&pstate, WJB_ELEM, val);
res = pushJsonbValue(&pstate, WJB_END_ARRAY, NULL);
out = convertToJsonb(res);
}
else if (val->type == jbvObject || val->type == jbvArray)
{
out = convertToJsonb(val);
}
else
{
Assert(val->type == jbvBinary);
out = palloc(VARHDRSZ + val->val.binary.len);
SET_VARSIZE(out, VARHDRSZ + val->val.binary.len);
memcpy(VARDATA(out), val->val.binary.data, val->val.binary.len);
}
return out;
}
/*
* Get the offset of the variable-length portion of a Jsonb node within
* the variable-length-data part of its container. The node is identified
* by index within the container's JEntry array.
*/
uint32
getJsonbOffset(const JsonbContainer *jc, int index)
{
uint32 offset = 0;
int i;
/*
* Start offset of this entry is equal to the end offset of the previous
* entry. Walk backwards to the most recent entry stored as an end
* offset, returning that offset plus any lengths in between.
*/
for (i = index - 1; i >= 0; i--)
{
offset += JBE_OFFLENFLD(jc->children[i]);
if (JBE_HAS_OFF(jc->children[i]))
break;
}
return offset;
}
/*
* Get the length of the variable-length portion of a Jsonb node.
* The node is identified by index within the container's JEntry array.
*/
uint32
getJsonbLength(const JsonbContainer *jc, int index)
{
uint32 off;
uint32 len;
/*
* If the length is stored directly in the JEntry, just return it.
* Otherwise, get the begin offset of the entry, and subtract that from
* the stored end+1 offset.
*/
if (JBE_HAS_OFF(jc->children[index]))
{
off = getJsonbOffset(jc, index);
len = JBE_OFFLENFLD(jc->children[index]) - off;
}
else
len = JBE_OFFLENFLD(jc->children[index]);
return len;
}
/*
* BT comparator worker function. Returns an integer less than, equal to, or
* greater than zero, indicating whether a is less than, equal to, or greater
* than b. Consistent with the requirements for a B-Tree operator class
*
* Strings are compared lexically, in contrast with other places where we use a
* much simpler comparator logic for searching through Strings. Since this is
* called from B-Tree support function 1, we're careful about not leaking
* memory here.
*/
int
compareJsonbContainers(JsonbContainer *a, JsonbContainer *b)
{
JsonbIterator *ita,
*itb;
int res = 0;
ita = JsonbIteratorInit(a);
itb = JsonbIteratorInit(b);
do
{
JsonbValue va,
vb;
JsonbIteratorToken ra,
rb;
ra = JsonbIteratorNext(&ita, &va, false);
rb = JsonbIteratorNext(&itb, &vb, false);
if (ra == rb)
{
if (ra == WJB_DONE)
{
/* Decisively equal */
break;
}
if (ra == WJB_END_ARRAY || ra == WJB_END_OBJECT)
{
/*
* There is no array or object to compare at this stage of
* processing. jbvArray/jbvObject values are compared
* initially, at the WJB_BEGIN_ARRAY and WJB_BEGIN_OBJECT
* tokens.
*/
continue;
}
if (va.type == vb.type)
{
switch (va.type)
{
case jbvString:
case jbvNull:
case jbvNumeric:
case jbvBool:
res = compareJsonbScalarValue(&va, &vb);
break;
case jbvArray:
/*
* This could be a "raw scalar" pseudo array. That's
* a special case here though, since we still want the
* general type-based comparisons to apply, and as far
* as we're concerned a pseudo array is just a scalar.
*/
if (va.val.array.rawScalar != vb.val.array.rawScalar)
res = (va.val.array.rawScalar) ? -1 : 1;
if (va.val.array.nElems != vb.val.array.nElems)
res = (va.val.array.nElems > vb.val.array.nElems) ? 1 : -1;
break;
case jbvObject:
if (va.val.object.nPairs != vb.val.object.nPairs)
res = (va.val.object.nPairs > vb.val.object.nPairs) ? 1 : -1;
break;
case jbvBinary:
elog(ERROR, "unexpected jbvBinary value");
}
}
else
{
/* Type-defined order */
res = (va.type > vb.type) ? 1 : -1;
}
}
else
{
/*
* It's safe to assume that the types differed, and that the va
* and vb values passed were set.
*
* If the two values were of the same container type, then there'd
* have been a chance to observe the variation in the number of
* elements/pairs (when processing WJB_BEGIN_OBJECT, say). They're
* either two heterogeneously-typed containers, or a container and
* some scalar type.
*
* We don't have to consider the WJB_END_ARRAY and WJB_END_OBJECT
* cases here, because we would have seen the corresponding
* WJB_BEGIN_ARRAY and WJB_BEGIN_OBJECT tokens first, and
* concluded that they don't match.
*/
Assert(ra != WJB_END_ARRAY && ra != WJB_END_OBJECT);
Assert(rb != WJB_END_ARRAY && rb != WJB_END_OBJECT);
Assert(va.type != vb.type);
Assert(va.type != jbvBinary);
Assert(vb.type != jbvBinary);
/* Type-defined order */
res = (va.type > vb.type) ? 1 : -1;
}
}
while (res == 0);
while (ita != NULL)
{
JsonbIterator *i = ita->parent;
pfree(ita);
ita = i;
}
while (itb != NULL)
{
JsonbIterator *i = itb->parent;
pfree(itb);
itb = i;
}
return res;
}
/*
* Find value in object (i.e. the "value" part of some key/value pair in an
* object), or find a matching element if we're looking through an array. Do
* so on the basis of equality of the object keys only, or alternatively
* element values only, with a caller-supplied value "key". The "flags"
* argument allows the caller to specify which container types are of interest.
*
* This exported utility function exists to facilitate various cases concerned
* with "containment". If asked to look through an object, the caller had
* better pass a Jsonb String, because their keys can only be strings.
* Otherwise, for an array, any type of JsonbValue will do.
*
* In order to proceed with the search, it is necessary for callers to have
* both specified an interest in exactly one particular container type with an
* appropriate flag, as well as having the pointed-to Jsonb container be of
* one of those same container types at the top level. (Actually, we just do
* whichever makes sense to save callers the trouble of figuring it out - at
* most one can make sense, because the container either points to an array
* (possibly a "raw scalar" pseudo array) or an object.)
*
* Note that we can return a jbvBinary JsonbValue if this is called on an
* object, but we never do so on an array. If the caller asks to look through
* a container type that is not of the type pointed to by the container,
* immediately fall through and return NULL. If we cannot find the value,
* return NULL. Otherwise, return palloc()'d copy of value.
*/
JsonbValue *
findJsonbValueFromContainer(JsonbContainer *container, uint32 flags,
JsonbValue *key)
{
JEntry *children = container->children;
int count = JsonContainerSize(container);
JsonbValue *result;
Assert((flags & ~(JB_FARRAY | JB_FOBJECT)) == 0);
/* Quick out without a palloc cycle if object/array is empty */
if (count <= 0)
return NULL;
result = palloc(sizeof(JsonbValue));
if ((flags & JB_FARRAY) && JsonContainerIsArray(container))
{
char *base_addr = (char *) (children + count);
uint32 offset = 0;
int i;
for (i = 0; i < count; i++)
{
fillJsonbValue(container, i, base_addr, offset, result);
if (key->type == result->type)
{
if (equalsJsonbScalarValue(key, result))
return result;
}
JBE_ADVANCE_OFFSET(offset, children[i]);
}
}
else if ((flags & JB_FOBJECT) && JsonContainerIsObject(container))
{
/* Since this is an object, account for *Pairs* of Jentrys */
char *base_addr = (char *) (children + count * 2);
uint32 stopLow = 0,
stopHigh = count;
/* Object key passed by caller must be a string */
Assert(key->type == jbvString);
/* Binary search on object/pair keys *only* */
while (stopLow < stopHigh)
{
uint32 stopMiddle;
int difference;
JsonbValue candidate;
stopMiddle = stopLow + (stopHigh - stopLow) / 2;
candidate.type = jbvString;
candidate.val.string.val =
base_addr + getJsonbOffset(container, stopMiddle);
candidate.val.string.len = getJsonbLength(container, stopMiddle);
difference = lengthCompareJsonbStringValue(&candidate, key);
if (difference == 0)
{
/* Found our key, return corresponding value */
int index = stopMiddle + count;
fillJsonbValue(container, index, base_addr,
getJsonbOffset(container, index),
result);
return result;
}
else
{
if (difference < 0)
stopLow = stopMiddle + 1;
else
stopHigh = stopMiddle;
}
}
}
/* Not found */
pfree(result);
return NULL;
}
/*
* Get i-th value of a Jsonb array.
*
* Returns palloc()'d copy of the value, or NULL if it does not exist.
*/
JsonbValue *
getIthJsonbValueFromContainer(JsonbContainer *container, uint32 i)
{
JsonbValue *result;
char *base_addr;
uint32 nelements;
if (!JsonContainerIsArray(container))
elog(ERROR, "not a jsonb array");
nelements = JsonContainerSize(container);
base_addr = (char *) &container->children[nelements];
if (i >= nelements)
return NULL;
result = palloc(sizeof(JsonbValue));
fillJsonbValue(container, i, base_addr,
getJsonbOffset(container, i),
result);
return result;
}
/*
* A helper function to fill in a JsonbValue to represent an element of an
* array, or a key or value of an object.
*
* The node's JEntry is at container->children[index], and its variable-length
* data is at base_addr + offset. We make the caller determine the offset
* since in many cases the caller can amortize that work across multiple
* children. When it can't, it can just call getJsonbOffset().
*
* A nested array or object will be returned as jbvBinary, ie. it won't be
* expanded.
*/
static void
fillJsonbValue(JsonbContainer *container, int index,
char *base_addr, uint32 offset,
JsonbValue *result)
{
JEntry entry = container->children[index];
if (JBE_ISNULL(entry))
{
result->type = jbvNull;
}
else if (JBE_ISSTRING(entry))
{
result->type = jbvString;
result->val.string.val = base_addr + offset;
result->val.string.len = getJsonbLength(container, index);
Assert(result->val.string.len >= 0);
}
else if (JBE_ISNUMERIC(entry))
{
result->type = jbvNumeric;
result->val.numeric = (Numeric) (base_addr + INTALIGN(offset));
}
else if (JBE_ISBOOL_TRUE(entry))
{
result->type = jbvBool;
result->val.boolean = true;
}
else if (JBE_ISBOOL_FALSE(entry))
{
result->type = jbvBool;
result->val.boolean = false;
}
else
{
Assert(JBE_ISCONTAINER(entry));
result->type = jbvBinary;
/* Remove alignment padding from data pointer and length */
result->val.binary.data = (JsonbContainer *) (base_addr + INTALIGN(offset));
result->val.binary.len = getJsonbLength(container, index) -
(INTALIGN(offset) - offset);
}
}
/*
* Push JsonbValue into JsonbParseState.
*
* Used when parsing JSON tokens to form Jsonb, or when converting an in-memory
* JsonbValue to a Jsonb.
*
* Initial state of *JsonbParseState is NULL, since it'll be allocated here
* originally (caller will get JsonbParseState back by reference).
*
* Only sequential tokens pertaining to non-container types should pass a
* JsonbValue. There is one exception -- WJB_BEGIN_ARRAY callers may pass a
* "raw scalar" pseudo array to append it - the actual scalar should be passed
* next and it will be added as the only member of the array.
*
* Values of type jvbBinary, which are rolled up arrays and objects,
* are unpacked before being added to the result.
*/
JsonbValue *
pushJsonbValue(JsonbParseState **pstate, JsonbIteratorToken seq,
JsonbValue *jbval)
{
JsonbIterator *it;
JsonbValue *res = NULL;
JsonbValue v;
JsonbIteratorToken tok;
if (!jbval || (seq != WJB_ELEM && seq != WJB_VALUE) ||
jbval->type != jbvBinary)
{
/* drop through */
return pushJsonbValueScalar(pstate, seq, jbval);
}
/* unpack the binary and add each piece to the pstate */
it = JsonbIteratorInit(jbval->val.binary.data);
while ((tok = JsonbIteratorNext(&it, &v, false)) != WJB_DONE)
res = pushJsonbValueScalar(pstate, tok,
tok < WJB_BEGIN_ARRAY ? &v : NULL);
return res;
}
/*
* Do the actual pushing, with only scalar or pseudo-scalar-array values
* accepted.
*/
static JsonbValue *
pushJsonbValueScalar(JsonbParseState **pstate, JsonbIteratorToken seq,
JsonbValue *scalarVal)
{
JsonbValue *result = NULL;
switch (seq)
{
case WJB_BEGIN_ARRAY:
Assert(!scalarVal || scalarVal->val.array.rawScalar);
*pstate = pushState(pstate);
result = &(*pstate)->contVal;
(*pstate)->contVal.type = jbvArray;
(*pstate)->contVal.val.array.nElems = 0;
(*pstate)->contVal.val.array.rawScalar = (scalarVal &&
scalarVal->val.array.rawScalar);
if (scalarVal && scalarVal->val.array.nElems > 0)
{
/* Assume that this array is still really a scalar */
Assert(scalarVal->type == jbvArray);
(*pstate)->size = scalarVal->val.array.nElems;
}
else
{
(*pstate)->size = 4;
}
(*pstate)->contVal.val.array.elems = palloc(sizeof(JsonbValue) *
(*pstate)->size);
break;
case WJB_BEGIN_OBJECT:
Assert(!scalarVal);
*pstate = pushState(pstate);
result = &(*pstate)->contVal;
(*pstate)->contVal.type = jbvObject;
(*pstate)->contVal.val.object.nPairs = 0;
(*pstate)->size = 4;
(*pstate)->contVal.val.object.pairs = palloc(sizeof(JsonbPair) *
(*pstate)->size);
break;
case WJB_KEY:
Assert(scalarVal->type == jbvString);
appendKey(*pstate, scalarVal);
break;
case WJB_VALUE:
Assert(IsAJsonbScalar(scalarVal));
appendValue(*pstate, scalarVal);
break;
case WJB_ELEM:
Assert(IsAJsonbScalar(scalarVal));
appendElement(*pstate, scalarVal);
break;
case WJB_END_OBJECT:
uniqueifyJsonbObject(&(*pstate)->contVal);
/* fall through! */
case WJB_END_ARRAY:
/* Steps here common to WJB_END_OBJECT case */
Assert(!scalarVal);
result = &(*pstate)->contVal;
/*
* Pop stack and push current array/object as value in parent
* array/object
*/
*pstate = (*pstate)->next;
if (*pstate)
{
switch ((*pstate)->contVal.type)
{
case jbvArray:
appendElement(*pstate, result);
break;
case jbvObject:
appendValue(*pstate, result);
break;
default:
elog(ERROR, "invalid jsonb container type");
}
}
break;
default:
elog(ERROR, "unrecognized jsonb sequential processing token");
}
return result;
}
/*
* pushJsonbValue() worker: Iteration-like forming of Jsonb
*/
static JsonbParseState *
pushState(JsonbParseState **pstate)
{
JsonbParseState *ns = palloc(sizeof(JsonbParseState));
ns->next = *pstate;
return ns;
}
/*
* pushJsonbValue() worker: Append a pair key to state when generating a Jsonb
*/
static void
appendKey(JsonbParseState *pstate, JsonbValue *string)
{
JsonbValue *object = &pstate->contVal;
Assert(object->type == jbvObject);
Assert(string->type == jbvString);
if (object->val.object.nPairs >= JSONB_MAX_PAIRS)
ereport(ERROR,
(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
errmsg("number of jsonb object pairs exceeds the maximum allowed (%zu)",
JSONB_MAX_PAIRS)));
if (object->val.object.nPairs >= pstate->size)
{
pstate->size *= 2;
object->val.object.pairs = repalloc(object->val.object.pairs,
sizeof(JsonbPair) * pstate->size);
}
object->val.object.pairs[object->val.object.nPairs].key = *string;
object->val.object.pairs[object->val.object.nPairs].order = object->val.object.nPairs;
}
/*
* pushJsonbValue() worker: Append a pair value to state when generating a
* Jsonb
*/
static void
appendValue(JsonbParseState *pstate, JsonbValue *scalarVal)
{
JsonbValue *object = &pstate->contVal;
Assert(object->type == jbvObject);
object->val.object.pairs[object->val.object.nPairs++].value = *scalarVal;
}
/*
* pushJsonbValue() worker: Append an element to state when generating a Jsonb
*/
static void
appendElement(JsonbParseState *pstate, JsonbValue *scalarVal)
{
JsonbValue *array = &pstate->contVal;
Assert(array->type == jbvArray);
if (array->val.array.nElems >= JSONB_MAX_ELEMS)
ereport(ERROR,
(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
errmsg("number of jsonb array elements exceeds the maximum allowed (%zu)",
JSONB_MAX_ELEMS)));
if (array->val.array.nElems >= pstate->size)
{
pstate->size *= 2;
array->val.array.elems = repalloc(array->val.array.elems,
sizeof(JsonbValue) * pstate->size);
}
array->val.array.elems[array->val.array.nElems++] = *scalarVal;
}
/*
* Given a JsonbContainer, expand to JsonbIterator to iterate over items
* fully expanded to in-memory representation for manipulation.
*
* See JsonbIteratorNext() for notes on memory management.
*/
JsonbIterator *
JsonbIteratorInit(JsonbContainer *container)
{
return iteratorFromContainer(container, NULL);
}
/*
* Get next JsonbValue while iterating
*
* Caller should initially pass their own, original iterator. They may get
* back a child iterator palloc()'d here instead. The function can be relied
* on to free those child iterators, lest the memory allocated for highly
* nested objects become unreasonable, but only if callers don't end iteration
* early (by breaking upon having found something in a search, for example).
*
* Callers in such a scenario, that are particularly sensitive to leaking
* memory in a long-lived context may walk the ancestral tree from the final
* iterator we left them with to its oldest ancestor, pfree()ing as they go.
* They do not have to free any other memory previously allocated for iterators
* but not accessible as direct ancestors of the iterator they're last passed
* back.
*
* Returns "Jsonb sequential processing" token value. Iterator "state"
* reflects the current stage of the process in a less granular fashion, and is
* mostly used here to track things internally with respect to particular
* iterators.
*
* Clients of this function should not have to handle any jbvBinary values
* (since recursive calls will deal with this), provided skipNested is false.
* It is our job to expand the jbvBinary representation without bothering them
* with it. However, clients should not take it upon themselves to touch array
* or Object element/pair buffers, since their element/pair pointers are
* garbage. Also, *val will not be set when returning WJB_END_ARRAY or
* WJB_END_OBJECT, on the assumption that it's only useful to access values
* when recursing in.
*/
JsonbIteratorToken
JsonbIteratorNext(JsonbIterator **it, JsonbValue *val, bool skipNested)
{
if (*it == NULL)
return WJB_DONE;
/*
* When stepping into a nested container, we jump back here to start
* processing the child. We will not recurse further in one call, because
* processing the child will always begin in JBI_ARRAY_START or
* JBI_OBJECT_START state.
*/
recurse:
switch ((*it)->state)
{
case JBI_ARRAY_START:
/* Set v to array on first array call */
val->type = jbvArray;
val->val.array.nElems = (*it)->nElems;
/*
* v->val.array.elems is not actually set, because we aren't doing
* a full conversion
*/
val->val.array.rawScalar = (*it)->isScalar;
(*it)->curIndex = 0;
(*it)->curDataOffset = 0;
(*it)->curValueOffset = 0; /* not actually used */
/* Set state for next call */
(*it)->state = JBI_ARRAY_ELEM;
return WJB_BEGIN_ARRAY;
case JBI_ARRAY_ELEM:
if ((*it)->curIndex >= (*it)->nElems)
{
/*
* All elements within array already processed. Report this
* to caller, and give it back original parent iterator (which
* independently tracks iteration progress at its level of
* nesting).
*/
*it = freeAndGetParent(*it);
return WJB_END_ARRAY;
}
fillJsonbValue((*it)->container, (*it)->curIndex,
(*it)->dataProper, (*it)->curDataOffset,
val);
JBE_ADVANCE_OFFSET((*it)->curDataOffset,
(*it)->children[(*it)->curIndex]);
(*it)->curIndex++;
if (!IsAJsonbScalar(val) && !skipNested)
{
/* Recurse into container. */
*it = iteratorFromContainer(val->val.binary.data, *it);
goto recurse;
}
else
{
/*
* Scalar item in array, or a container and caller didn't want
* us to recurse into it.
*/
return WJB_ELEM;
}
case JBI_OBJECT_START:
/* Set v to object on first object call */
val->type = jbvObject;
val->val.object.nPairs = (*it)->nElems;
/*
* v->val.object.pairs is not actually set, because we aren't
* doing a full conversion
*/
(*it)->curIndex = 0;
(*it)->curDataOffset = 0;
(*it)->curValueOffset = getJsonbOffset((*it)->container,
(*it)->nElems);
/* Set state for next call */
(*it)->state = JBI_OBJECT_KEY;
return WJB_BEGIN_OBJECT;
case JBI_OBJECT_KEY:
if ((*it)->curIndex >= (*it)->nElems)
{
/*
* All pairs within object already processed. Report this to
* caller, and give it back original containing iterator
* (which independently tracks iteration progress at its level
* of nesting).
*/
*it = freeAndGetParent(*it);
return WJB_END_OBJECT;
}
else
{
/* Return key of a key/value pair. */
fillJsonbValue((*it)->container, (*it)->curIndex,
(*it)->dataProper, (*it)->curDataOffset,
val);
if (val->type != jbvString)
elog(ERROR, "unexpected jsonb type as object key");
/* Set state for next call */
(*it)->state = JBI_OBJECT_VALUE;
return WJB_KEY;
}
case JBI_OBJECT_VALUE:
/* Set state for next call */
(*it)->state = JBI_OBJECT_KEY;
fillJsonbValue((*it)->container, (*it)->curIndex + (*it)->nElems,
(*it)->dataProper, (*it)->curValueOffset,
val);
JBE_ADVANCE_OFFSET((*it)->curDataOffset,
(*it)->children[(*it)->curIndex]);
JBE_ADVANCE_OFFSET((*it)->curValueOffset,
(*it)->children[(*it)->curIndex + (*it)->nElems]);
(*it)->curIndex++;
/*
* Value may be a container, in which case we recurse with new,
* child iterator (unless the caller asked not to, by passing
* skipNested).
*/
if (!IsAJsonbScalar(val) && !skipNested)
{
*it = iteratorFromContainer(val->val.binary.data, *it);
goto recurse;
}
else
return WJB_VALUE;
}
elog(ERROR, "invalid iterator state");
return -1;
}
/*
* Initialize an iterator for iterating all elements in a container.
*/
static JsonbIterator *
iteratorFromContainer(JsonbContainer *container, JsonbIterator *parent)
{
JsonbIterator *it;
it = palloc0(sizeof(JsonbIterator));
it->container = container;
it->parent = parent;
it->nElems = JsonContainerSize(container);
/* Array starts just after header */
it->children = container->children;
switch (container->header & (JB_FARRAY | JB_FOBJECT))
{
case JB_FARRAY:
it->dataProper =
(char *) it->children + it->nElems * sizeof(JEntry);
it->isScalar = JsonContainerIsScalar(container);
/* This is either a "raw scalar", or an array */
Assert(!it->isScalar || it->nElems == 1);
it->state = JBI_ARRAY_START;
break;
case JB_FOBJECT:
it->dataProper =
(char *) it->children + it->nElems * sizeof(JEntry) * 2;
it->state = JBI_OBJECT_START;
break;
default:
elog(ERROR, "unknown type of jsonb container");
}
return it;
}
/*
* JsonbIteratorNext() worker: Return parent, while freeing memory for current
* iterator
*/
static JsonbIterator *
freeAndGetParent(JsonbIterator *it)
{
JsonbIterator *v = it->parent;
pfree(it);
return v;
}
/*
* Worker for "contains" operator's function
*
* Formally speaking, containment is top-down, unordered subtree isomorphism.
*
* Takes iterators that belong to some container type. These iterators
* "belong" to those values in the sense that they've just been initialized in
* respect of them by the caller (perhaps in a nested fashion).
*
* "val" is lhs Jsonb, and mContained is rhs Jsonb when called from top level.
* We determine if mContained is contained within val.
*/
bool
JsonbDeepContains(JsonbIterator **val, JsonbIterator **mContained)
{
JsonbValue vval,
vcontained;
JsonbIteratorToken rval,
rcont;
/*
* Guard against stack overflow due to overly complex Jsonb.
*
* Functions called here independently take this precaution, but that
* might not be sufficient since this is also a recursive function.
*/
check_stack_depth();
rval = JsonbIteratorNext(val, &vval, false);
rcont = JsonbIteratorNext(mContained, &vcontained, false);
if (rval != rcont)
{
/*
* The differing return values can immediately be taken as indicating
* two differing container types at this nesting level, which is
* sufficient reason to give up entirely (but it should be the case
* that they're both some container type).
*/
Assert(rval == WJB_BEGIN_OBJECT || rval == WJB_BEGIN_ARRAY);
Assert(rcont == WJB_BEGIN_OBJECT || rcont == WJB_BEGIN_ARRAY);
return false;
}
else if (rcont == WJB_BEGIN_OBJECT)
{
Assert(vval.type == jbvObject);
Assert(vcontained.type == jbvObject);
/*
* If the lhs has fewer pairs than the rhs, it can't possibly contain
* the rhs. (This conclusion is safe only because we de-duplicate
* keys in all Jsonb objects; thus there can be no corresponding
* optimization in the array case.) The case probably won't arise
* often, but since it's such a cheap check we may as well make it.
*/
if (vval.val.object.nPairs < vcontained.val.object.nPairs)
return false;
/* Work through rhs "is it contained within?" object */
for (;;)
{
JsonbValue *lhsVal; /* lhsVal is from pair in lhs object */
rcont = JsonbIteratorNext(mContained, &vcontained, false);
/*
* When we get through caller's rhs "is it contained within?"
* object without failing to find one of its values, it's
* contained.
*/
if (rcont == WJB_END_OBJECT)
return true;
Assert(rcont == WJB_KEY);
/* First, find value by key... */
lhsVal = findJsonbValueFromContainer((*val)->container,
JB_FOBJECT,
&vcontained);
if (!lhsVal)
return false;
/*
* ...at this stage it is apparent that there is at least a key
* match for this rhs pair.
*/
rcont = JsonbIteratorNext(mContained, &vcontained, true);
Assert(rcont == WJB_VALUE);
/*
* Compare rhs pair's value with lhs pair's value just found using
* key
*/
if (lhsVal->type != vcontained.type)
{
return false;
}
else if (IsAJsonbScalar(lhsVal))
{
if (!equalsJsonbScalarValue(lhsVal, &vcontained))
return false;
}
else
{
/* Nested container value (object or array) */
JsonbIterator *nestval,
*nestContained;
Assert(lhsVal->type == jbvBinary);
Assert(vcontained.type == jbvBinary);
nestval = JsonbIteratorInit(lhsVal->val.binary.data);
nestContained = JsonbIteratorInit(vcontained.val.binary.data);
/*
* Match "value" side of rhs datum object's pair recursively.
* It's a nested structure.
*
* Note that nesting still has to "match up" at the right
* nesting sub-levels. However, there need only be zero or
* more matching pairs (or elements) at each nesting level
* (provided the *rhs* pairs/elements *all* match on each
* level), which enables searching nested structures for a
* single String or other primitive type sub-datum quite
* effectively (provided the user constructed the rhs nested
* structure such that we "know where to look").
*
* In other words, the mapping of container nodes in the rhs
* "vcontained" Jsonb to internal nodes on the lhs is
* injective, and parent-child edges on the rhs must be mapped
* to parent-child edges on the lhs to satisfy the condition
* of containment (plus of course the mapped nodes must be
* equal).
*/
if (!JsonbDeepContains(&nestval, &nestContained))
return false;
}
}
}
else if (rcont == WJB_BEGIN_ARRAY)
{
JsonbValue *lhsConts = NULL;
uint32 nLhsElems = vval.val.array.nElems;
Assert(vval.type == jbvArray);
Assert(vcontained.type == jbvArray);
/*
* Handle distinction between "raw scalar" pseudo arrays, and real
* arrays.
*
* A raw scalar may contain another raw scalar, and an array may
* contain a raw scalar, but a raw scalar may not contain an array. We
* don't do something like this for the object case, since objects can
* only contain pairs, never raw scalars (a pair is represented by an
* rhs object argument with a single contained pair).
*/
if (vval.val.array.rawScalar && !vcontained.val.array.rawScalar)
return false;
/* Work through rhs "is it contained within?" array */
for (;;)
{
rcont = JsonbIteratorNext(mContained, &vcontained, true);
/*
* When we get through caller's rhs "is it contained within?"
* array without failing to find one of its values, it's
* contained.
*/
if (rcont == WJB_END_ARRAY)
return true;
Assert(rcont == WJB_ELEM);
if (IsAJsonbScalar(&vcontained))
{
if (!findJsonbValueFromContainer((*val)->container,
JB_FARRAY,
&vcontained))
return false;
}
else
{
uint32 i;
/*
* If this is first container found in rhs array (at this
* depth), initialize temp lhs array of containers
*/
if (lhsConts == NULL)
{
uint32 j = 0;
/* Make room for all possible values */
lhsConts = palloc(sizeof(JsonbValue) * nLhsElems);
for (i = 0; i < nLhsElems; i++)
{
/* Store all lhs elements in temp array */
rcont = JsonbIteratorNext(val, &vval, true);
Assert(rcont == WJB_ELEM);
if (vval.type == jbvBinary)
lhsConts[j++] = vval;
}
/* No container elements in temp array, so give up now */
if (j == 0)
return false;
/* We may have only partially filled array */
nLhsElems = j;
}
/* XXX: Nested array containment is O(N^2) */
for (i = 0; i < nLhsElems; i++)
{
/* Nested container value (object or array) */
JsonbIterator *nestval,
*nestContained;
bool contains;
nestval = JsonbIteratorInit(lhsConts[i].val.binary.data);
nestContained = JsonbIteratorInit(vcontained.val.binary.data);
contains = JsonbDeepContains(&nestval, &nestContained);
if (nestval)
pfree(nestval);
if (nestContained)
pfree(nestContained);
if (contains)
break;
}
/*
* Report rhs container value is not contained if couldn't
* match rhs container to *some* lhs cont
*/
if (i == nLhsElems)
return false;
}
}
}
else
{
elog(ERROR, "invalid jsonb container type");
}
elog(ERROR, "unexpectedly fell off end of jsonb container");
return false;
}
/*
* Hash a JsonbValue scalar value, mixing the hash value into an existing
* hash provided by the caller.
*
* Some callers may wish to independently XOR in JB_FOBJECT and JB_FARRAY
* flags.
*/
void
JsonbHashScalarValue(const JsonbValue *scalarVal, uint32 *hash)
{
uint32 tmp;
/* Compute hash value for scalarVal */
switch (scalarVal->type)
{
case jbvNull:
tmp = 0x01;
break;
case jbvString:
tmp = DatumGetUInt32(hash_any((const unsigned char *) scalarVal->val.string.val,
scalarVal->val.string.len));
break;
case jbvNumeric:
/* Must hash equal numerics to equal hash codes */
tmp = DatumGetUInt32(DirectFunctionCall1(hash_numeric,
NumericGetDatum(scalarVal->val.numeric)));
break;
case jbvBool:
tmp = scalarVal->val.boolean ? 0x02 : 0x04;
break;
default:
elog(ERROR, "invalid jsonb scalar type");
tmp = 0; /* keep compiler quiet */
break;
}
/*
* Combine hash values of successive keys, values and elements by rotating
* the previous value left 1 bit, then XOR'ing in the new
* key/value/element's hash value.
*/
*hash = (*hash << 1) | (*hash >> 31);
*hash ^= tmp;
}
/*
* Hash a value to a 64-bit value, with a seed. Otherwise, similar to
* JsonbHashScalarValue.
*/
void
JsonbHashScalarValueExtended(const JsonbValue *scalarVal, uint64 *hash,
uint64 seed)
{
uint64 tmp;
switch (scalarVal->type)
{
case jbvNull:
tmp = seed + 0x01;
break;
case jbvString:
tmp = DatumGetUInt64(hash_any_extended((const unsigned char *) scalarVal->val.string.val,
scalarVal->val.string.len,
seed));
break;
case jbvNumeric:
tmp = DatumGetUInt64(DirectFunctionCall2(hash_numeric_extended,
NumericGetDatum(scalarVal->val.numeric),
UInt64GetDatum(seed)));
break;
case jbvBool:
if (seed)
tmp = DatumGetUInt64(DirectFunctionCall2(hashcharextended,
BoolGetDatum(scalarVal->val.boolean),
UInt64GetDatum(seed)));
else
tmp = scalarVal->val.boolean ? 0x02 : 0x04;
break;
default:
elog(ERROR, "invalid jsonb scalar type");
break;
}
*hash = ROTATE_HIGH_AND_LOW_32BITS(*hash);
*hash ^= tmp;
}
/*
* Are two scalar JsonbValues of the same type a and b equal?
*/
static bool
equalsJsonbScalarValue(JsonbValue *aScalar, JsonbValue *bScalar)
{
if (aScalar->type == bScalar->type)
{
switch (aScalar->type)
{
case jbvNull:
return true;
case jbvString:
return lengthCompareJsonbStringValue(aScalar, bScalar) == 0;
case jbvNumeric:
return DatumGetBool(DirectFunctionCall2(numeric_eq,
PointerGetDatum(aScalar->val.numeric),
PointerGetDatum(bScalar->val.numeric)));
case jbvBool:
return aScalar->val.boolean == bScalar->val.boolean;
default:
elog(ERROR, "invalid jsonb scalar type");
}
}
elog(ERROR, "jsonb scalar type mismatch");
return false;
}
/*
* Compare two scalar JsonbValues, returning -1, 0, or 1.
*
* Strings are compared using the default collation. Used by B-tree
* operators, where a lexical sort order is generally expected.
*/
static int
compareJsonbScalarValue(JsonbValue *aScalar, JsonbValue *bScalar)
{
if (aScalar->type == bScalar->type)
{
switch (aScalar->type)
{
case jbvNull:
return 0;
case jbvString:
return varstr_cmp(aScalar->val.string.val,
aScalar->val.string.len,
bScalar->val.string.val,
bScalar->val.string.len,
DEFAULT_COLLATION_OID);
case jbvNumeric:
return DatumGetInt32(DirectFunctionCall2(numeric_cmp,
PointerGetDatum(aScalar->val.numeric),
PointerGetDatum(bScalar->val.numeric)));
case jbvBool:
if (aScalar->val.boolean == bScalar->val.boolean)
return 0;
else if (aScalar->val.boolean > bScalar->val.boolean)
return 1;
else
return -1;
default:
elog(ERROR, "invalid jsonb scalar type");
}
}
elog(ERROR, "jsonb scalar type mismatch");
return -1;
}
/*
* Functions for manipulating the resizable buffer used by convertJsonb and
* its subroutines.
*/
/*
* Reserve 'len' bytes, at the end of the buffer, enlarging it if necessary.
* Returns the offset to the reserved area. The caller is expected to fill
* the reserved area later with copyToBuffer().
*/
static int
reserveFromBuffer(StringInfo buffer, int len)
{
int offset;
/* Make more room if needed */
enlargeStringInfo(buffer, len);
/* remember current offset */
offset = buffer->len;
/* reserve the space */
buffer->len += len;
/*
* Keep a trailing null in place, even though it's not useful for us; it
* seems best to preserve the invariants of StringInfos.
*/
buffer->data[buffer->len] = '\0';
return offset;
}
/*
* Copy 'len' bytes to a previously reserved area in buffer.
*/
static void
copyToBuffer(StringInfo buffer, int offset, const char *data, int len)
{
memcpy(buffer->data + offset, data, len);
}
/*
* A shorthand for reserveFromBuffer + copyToBuffer.
*/
static void
appendToBuffer(StringInfo buffer, const char *data, int len)
{
int offset;
offset = reserveFromBuffer(buffer, len);
copyToBuffer(buffer, offset, data, len);
}
/*
* Append padding, so that the length of the StringInfo is int-aligned.
* Returns the number of padding bytes appended.
*/
static short
padBufferToInt(StringInfo buffer)
{
int padlen,
p,
offset;
padlen = INTALIGN(buffer->len) - buffer->len;
offset = reserveFromBuffer(buffer, padlen);
/* padlen must be small, so this is probably faster than a memset */
for (p = 0; p < padlen; p++)
buffer->data[offset + p] = '\0';
return padlen;
}
/*
* Given a JsonbValue, convert to Jsonb. The result is palloc'd.
*/
static Jsonb *
convertToJsonb(JsonbValue *val)
{
StringInfoData buffer;
JEntry jentry;
Jsonb *res;
/* Should not already have binary representation */
Assert(val->type != jbvBinary);
/* Allocate an output buffer. It will be enlarged as needed */
initStringInfo(&buffer);
/* Make room for the varlena header */
reserveFromBuffer(&buffer, VARHDRSZ);
convertJsonbValue(&buffer, &jentry, val, 0);
/*
* Note: the JEntry of the root is discarded. Therefore the root
* JsonbContainer struct must contain enough information to tell what kind
* of value it is.
*/
res = (Jsonb *) buffer.data;
SET_VARSIZE(res, buffer.len);
return res;
}
/*
* Subroutine of convertJsonb: serialize a single JsonbValue into buffer.
*
* The JEntry header for this node is returned in *header. It is filled in
* with the length of this value and appropriate type bits. If we wish to
* store an end offset rather than a length, it is the caller's responsibility
* to adjust for that.
*
* If the value is an array or an object, this recurses. 'level' is only used
* for debugging purposes.
*/
static void
convertJsonbValue(StringInfo buffer, JEntry *header, JsonbValue *val, int level)
{
check_stack_depth();
if (!val)
return;
/*
* A JsonbValue passed as val should never have a type of jbvBinary, and
* neither should any of its sub-components. Those values will be produced
* by convertJsonbArray and convertJsonbObject, the results of which will
* not be passed back to this function as an argument.
*/
if (IsAJsonbScalar(val))
convertJsonbScalar(buffer, header, val);
else if (val->type == jbvArray)
convertJsonbArray(buffer, header, val, level);
else if (val->type == jbvObject)
convertJsonbObject(buffer, header, val, level);
else
elog(ERROR, "unknown type of jsonb container to convert");
}
static void
convertJsonbArray(StringInfo buffer, JEntry *pheader, JsonbValue *val, int level)
{
int base_offset;
int jentry_offset;
int i;
int totallen;
uint32 header;
int nElems = val->val.array.nElems;
/* Remember where in the buffer this array starts. */
base_offset = buffer->len;
/* Align to 4-byte boundary (any padding counts as part of my data) */
padBufferToInt(buffer);
/*
* Construct the header Jentry and store it in the beginning of the
* variable-length payload.
*/
header = nElems | JB_FARRAY;
if (val->val.array.rawScalar)
{
Assert(nElems == 1);
Assert(level == 0);
header |= JB_FSCALAR;
}
appendToBuffer(buffer, (char *) &header, sizeof(uint32));
/* Reserve space for the JEntries of the elements. */
jentry_offset = reserveFromBuffer(buffer, sizeof(JEntry) * nElems);
totallen = 0;
for (i = 0; i < nElems; i++)
{
JsonbValue *elem = &val->val.array.elems[i];
int len;
JEntry meta;
/*
* Convert element, producing a JEntry and appending its
* variable-length data to buffer
*/
convertJsonbValue(buffer, &meta, elem, level + 1);
len = JBE_OFFLENFLD(meta);
totallen += len;
/*
* Bail out if total variable-length data exceeds what will fit in a
* JEntry length field. We check this in each iteration, not just
* once at the end, to forestall possible integer overflow.
*/
if (totallen > JENTRY_OFFLENMASK)
ereport(ERROR,
(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
errmsg("total size of jsonb array elements exceeds the maximum of %u bytes",
JENTRY_OFFLENMASK)));
/*
* Convert each JB_OFFSET_STRIDE'th length to an offset.
*/
if ((i % JB_OFFSET_STRIDE) == 0)
meta = (meta & JENTRY_TYPEMASK) | totallen | JENTRY_HAS_OFF;
copyToBuffer(buffer, jentry_offset, (char *) &meta, sizeof(JEntry));
jentry_offset += sizeof(JEntry);
}
/* Total data size is everything we've appended to buffer */
totallen = buffer->len - base_offset;
/* Check length again, since we didn't include the metadata above */
if (totallen > JENTRY_OFFLENMASK)
ereport(ERROR,
(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
errmsg("total size of jsonb array elements exceeds the maximum of %u bytes",
JENTRY_OFFLENMASK)));
/* Initialize the header of this node in the container's JEntry array */
*pheader = JENTRY_ISCONTAINER | totallen;
}
static void
convertJsonbObject(StringInfo buffer, JEntry *pheader, JsonbValue *val, int level)
{
int base_offset;
int jentry_offset;
int i;
int totallen;
uint32 header;
int nPairs = val->val.object.nPairs;
/* Remember where in the buffer this object starts. */
base_offset = buffer->len;
/* Align to 4-byte boundary (any padding counts as part of my data) */
padBufferToInt(buffer);
/*
* Construct the header Jentry and store it in the beginning of the
* variable-length payload.
*/
header = nPairs | JB_FOBJECT;
appendToBuffer(buffer, (char *) &header, sizeof(uint32));
/* Reserve space for the JEntries of the keys and values. */
jentry_offset = reserveFromBuffer(buffer, sizeof(JEntry) * nPairs * 2);
/*
* Iterate over the keys, then over the values, since that is the ordering
* we want in the on-disk representation.
*/
totallen = 0;
for (i = 0; i < nPairs; i++)
{
JsonbPair *pair = &val->val.object.pairs[i];
int len;
JEntry meta;
/*
* Convert key, producing a JEntry and appending its variable-length
* data to buffer
*/
convertJsonbScalar(buffer, &meta, &pair->key);
len = JBE_OFFLENFLD(meta);
totallen += len;
/*
* Bail out if total variable-length data exceeds what will fit in a
* JEntry length field. We check this in each iteration, not just
* once at the end, to forestall possible integer overflow.
*/
if (totallen > JENTRY_OFFLENMASK)
ereport(ERROR,
(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
errmsg("total size of jsonb object elements exceeds the maximum of %u bytes",
JENTRY_OFFLENMASK)));
/*
* Convert each JB_OFFSET_STRIDE'th length to an offset.
*/
if ((i % JB_OFFSET_STRIDE) == 0)
meta = (meta & JENTRY_TYPEMASK) | totallen | JENTRY_HAS_OFF;
copyToBuffer(buffer, jentry_offset, (char *) &meta, sizeof(JEntry));
jentry_offset += sizeof(JEntry);
}
for (i = 0; i < nPairs; i++)
{
JsonbPair *pair = &val->val.object.pairs[i];
int len;
JEntry meta;
/*
* Convert value, producing a JEntry and appending its variable-length
* data to buffer
*/
convertJsonbValue(buffer, &meta, &pair->value, level + 1);
len = JBE_OFFLENFLD(meta);
totallen += len;
/*
* Bail out if total variable-length data exceeds what will fit in a
* JEntry length field. We check this in each iteration, not just
* once at the end, to forestall possible integer overflow.
*/
if (totallen > JENTRY_OFFLENMASK)
ereport(ERROR,
(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
errmsg("total size of jsonb object elements exceeds the maximum of %u bytes",
JENTRY_OFFLENMASK)));
/*
* Convert each JB_OFFSET_STRIDE'th length to an offset.
*/
if (((i + nPairs) % JB_OFFSET_STRIDE) == 0)
meta = (meta & JENTRY_TYPEMASK) | totallen | JENTRY_HAS_OFF;
copyToBuffer(buffer, jentry_offset, (char *) &meta, sizeof(JEntry));
jentry_offset += sizeof(JEntry);
}
/* Total data size is everything we've appended to buffer */
totallen = buffer->len - base_offset;
/* Check length again, since we didn't include the metadata above */
if (totallen > JENTRY_OFFLENMASK)
ereport(ERROR,
(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
errmsg("total size of jsonb object elements exceeds the maximum of %u bytes",
JENTRY_OFFLENMASK)));
/* Initialize the header of this node in the container's JEntry array */
*pheader = JENTRY_ISCONTAINER | totallen;
}
static void
convertJsonbScalar(StringInfo buffer, JEntry *jentry, JsonbValue *scalarVal)
{
int numlen;
short padlen;
switch (scalarVal->type)
{
case jbvNull:
*jentry = JENTRY_ISNULL;
break;
case jbvString:
appendToBuffer(buffer, scalarVal->val.string.val, scalarVal->val.string.len);
*jentry = scalarVal->val.string.len;
break;
case jbvNumeric:
/* replace numeric NaN with string "NaN" */
if (numeric_is_nan(scalarVal->val.numeric))
{
appendToBuffer(buffer, "NaN", 3);
*jentry = 3;
break;
}
numlen = VARSIZE_ANY(scalarVal->val.numeric);
padlen = padBufferToInt(buffer);
appendToBuffer(buffer, (char *) scalarVal->val.numeric, numlen);
*jentry = JENTRY_ISNUMERIC | (padlen + numlen);
break;
case jbvBool:
*jentry = (scalarVal->val.boolean) ?
JENTRY_ISBOOL_TRUE : JENTRY_ISBOOL_FALSE;
break;
default:
elog(ERROR, "invalid jsonb scalar type");
}
}
/*
* Compare two jbvString JsonbValue values, a and b.
*
* This is a special qsort() comparator used to sort strings in certain
* internal contexts where it is sufficient to have a well-defined sort order.
* In particular, object pair keys are sorted according to this criteria to
* facilitate cheap binary searches where we don't care about lexical sort
* order.
*
* a and b are first sorted based on their length. If a tie-breaker is
* required, only then do we consider string binary equality.
*/
static int
lengthCompareJsonbStringValue(const void *a, const void *b)
{
const JsonbValue *va = (const JsonbValue *) a;
const JsonbValue *vb = (const JsonbValue *) b;
int res;
Assert(va->type == jbvString);
Assert(vb->type == jbvString);
if (va->val.string.len == vb->val.string.len)
{
res = memcmp(va->val.string.val, vb->val.string.val, va->val.string.len);
}
else
{
res = (va->val.string.len > vb->val.string.len) ? 1 : -1;
}
return res;
}
/*
* qsort_arg() comparator to compare JsonbPair values.
*
* Third argument 'binequal' may point to a bool. If it's set, *binequal is set
* to true iff a and b have full binary equality, since some callers have an
* interest in whether the two values are equal or merely equivalent.
*
* N.B: String comparisons here are "length-wise"
*
* Pairs with equals keys are ordered such that the order field is respected.
*/
static int
lengthCompareJsonbPair(const void *a, const void *b, void *binequal)
{
const JsonbPair *pa = (const JsonbPair *) a;
const JsonbPair *pb = (const JsonbPair *) b;
int res;
res = lengthCompareJsonbStringValue(&pa->key, &pb->key);
if (res == 0 && binequal)
*((bool *) binequal) = true;
/*
* Guarantee keeping order of equal pair. Unique algorithm will prefer
* first element as value.
*/
if (res == 0)
res = (pa->order > pb->order) ? -1 : 1;
return res;
}
/*
* Sort and unique-ify pairs in JsonbValue object
*/
static void
uniqueifyJsonbObject(JsonbValue *object)
{
bool hasNonUniq = false;
Assert(object->type == jbvObject);
if (object->val.object.nPairs > 1)
qsort_arg(object->val.object.pairs, object->val.object.nPairs, sizeof(JsonbPair),
lengthCompareJsonbPair, &hasNonUniq);
if (hasNonUniq)
{
JsonbPair *ptr = object->val.object.pairs + 1,
*res = object->val.object.pairs;
while (ptr - object->val.object.pairs < object->val.object.nPairs)
{
/* Avoid copying over duplicate */
if (lengthCompareJsonbStringValue(ptr, res) != 0)
{
res++;
if (ptr != res)
memcpy(res, ptr, sizeof(JsonbPair));
}
ptr++;
}
object->val.object.nPairs = res + 1 - object->val.object.pairs;
}
}
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