Adding upstream version 15.5.upstream/15.5

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 415 insertions, 0 deletions

diff --git a/src/include/utils/jsonb.h b/src/include/utils/jsonb.h
new file mode 100644
index 0000000..4cbe6ed
--- /dev/null
+++ b/src/include/utils/jsonb.h
@@ -0,0 +1,415 @@
+/*-------------------------------------------------------------------------
+ *
+ * jsonb.h
+ *	  Declarations for jsonb data type support.
+ *
+ * Copyright (c) 1996-2022, PostgreSQL Global Development Group
+ *
+ * src/include/utils/jsonb.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef __JSONB_H__
+#define __JSONB_H__
+
+#include "lib/stringinfo.h"
+#include "utils/array.h"
+#include "utils/numeric.h"
+
+/* Tokens used when sequentially processing a jsonb value */
+typedef enum
+{
+	WJB_DONE,
+	WJB_KEY,
+	WJB_VALUE,
+	WJB_ELEM,
+	WJB_BEGIN_ARRAY,
+	WJB_END_ARRAY,
+	WJB_BEGIN_OBJECT,
+	WJB_END_OBJECT
+} JsonbIteratorToken;
+
+/* Strategy numbers for GIN index opclasses */
+#define JsonbContainsStrategyNumber		7
+#define JsonbExistsStrategyNumber		9
+#define JsonbExistsAnyStrategyNumber	10
+#define JsonbExistsAllStrategyNumber	11
+#define JsonbJsonpathExistsStrategyNumber		15
+#define JsonbJsonpathPredicateStrategyNumber	16
+
+
+/*
+ * In the standard jsonb_ops GIN opclass for jsonb, we choose to index both
+ * keys and values.  The storage format is text.  The first byte of the text
+ * string distinguishes whether this is a key (always a string), null value,
+ * boolean value, numeric value, or string value.  However, array elements
+ * that are strings are marked as though they were keys; this imprecision
+ * supports the definition of the "exists" operator, which treats array
+ * elements like keys.  The remainder of the text string is empty for a null
+ * value, "t" or "f" for a boolean value, a normalized print representation of
+ * a numeric value, or the text of a string value.  However, if the length of
+ * this text representation would exceed JGIN_MAXLENGTH bytes, we instead hash
+ * the text representation and store an 8-hex-digit representation of the
+ * uint32 hash value, marking the prefix byte with an additional bit to
+ * distinguish that this has happened.  Hashing long strings saves space and
+ * ensures that we won't overrun the maximum entry length for a GIN index.
+ * (But JGIN_MAXLENGTH is quite a bit shorter than GIN's limit.  It's chosen
+ * to ensure that the on-disk text datum will have a short varlena header.)
+ * Note that when any hashed item appears in a query, we must recheck index
+ * matches against the heap tuple; currently, this costs nothing because we
+ * must always recheck for other reasons.
+ */
+#define JGINFLAG_KEY	0x01	/* key (or string array element) */
+#define JGINFLAG_NULL	0x02	/* null value */
+#define JGINFLAG_BOOL	0x03	/* boolean value */
+#define JGINFLAG_NUM	0x04	/* numeric value */
+#define JGINFLAG_STR	0x05	/* string value (if not an array element) */
+#define JGINFLAG_HASHED 0x10	/* OR'd into flag if value was hashed */
+#define JGIN_MAXLENGTH	125		/* max length of text part before hashing */
+
+/* Convenience macros */
+#define DatumGetJsonbP(d)	((Jsonb *) PG_DETOAST_DATUM(d))
+#define DatumGetJsonbPCopy(d)	((Jsonb *) PG_DETOAST_DATUM_COPY(d))
+#define JsonbPGetDatum(p)	PointerGetDatum(p)
+#define PG_GETARG_JSONB_P(x)	DatumGetJsonbP(PG_GETARG_DATUM(x))
+#define PG_GETARG_JSONB_P_COPY(x)	DatumGetJsonbPCopy(PG_GETARG_DATUM(x))
+#define PG_RETURN_JSONB_P(x)	PG_RETURN_POINTER(x)
+
+typedef struct JsonbPair JsonbPair;
+typedef struct JsonbValue JsonbValue;
+
+/*
+ * Jsonbs are varlena objects, so must meet the varlena convention that the
+ * first int32 of the object contains the total object size in bytes.  Be sure
+ * to use VARSIZE() and SET_VARSIZE() to access it, though!
+ *
+ * Jsonb is the on-disk representation, in contrast to the in-memory JsonbValue
+ * representation.  Often, JsonbValues are just shims through which a Jsonb
+ * buffer is accessed, but they can also be deep copied and passed around.
+ *
+ * Jsonb is a tree structure. Each node in the tree consists of a JEntry
+ * header and a variable-length content (possibly of zero size).  The JEntry
+ * header indicates what kind of a node it is, e.g. a string or an array,
+ * and provides the length of its variable-length portion.
+ *
+ * The JEntry and the content of a node are not stored physically together.
+ * Instead, the container array or object has an array that holds the JEntrys
+ * of all the child nodes, followed by their variable-length portions.
+ *
+ * The root node is an exception; it has no parent array or object that could
+ * hold its JEntry. Hence, no JEntry header is stored for the root node.  It
+ * is implicitly known that the root node must be an array or an object,
+ * so we can get away without the type indicator as long as we can distinguish
+ * the two.  For that purpose, both an array and an object begin with a uint32
+ * header field, which contains an JB_FOBJECT or JB_FARRAY flag.  When a naked
+ * scalar value needs to be stored as a Jsonb value, what we actually store is
+ * an array with one element, with the flags in the array's header field set
+ * to JB_FSCALAR | JB_FARRAY.
+ *
+ * Overall, the Jsonb struct requires 4-bytes alignment. Within the struct,
+ * the variable-length portion of some node types is aligned to a 4-byte
+ * boundary, while others are not. When alignment is needed, the padding is
+ * in the beginning of the node that requires it. For example, if a numeric
+ * node is stored after a string node, so that the numeric node begins at
+ * offset 3, the variable-length portion of the numeric node will begin with
+ * one padding byte so that the actual numeric data is 4-byte aligned.
+ */
+
+/*
+ * JEntry format.
+ *
+ * The least significant 28 bits store either the data length of the entry,
+ * or its end+1 offset from the start of the variable-length portion of the
+ * containing object.  The next three bits store the type of the entry, and
+ * the high-order bit tells whether the least significant bits store a length
+ * or an offset.
+ *
+ * The reason for the offset-or-length complication is to compromise between
+ * access speed and data compressibility.  In the initial design each JEntry
+ * always stored an offset, but this resulted in JEntry arrays with horrible
+ * compressibility properties, so that TOAST compression of a JSONB did not
+ * work well.  Storing only lengths would greatly improve compressibility,
+ * but it makes random access into large arrays expensive (O(N) not O(1)).
+ * So what we do is store an offset in every JB_OFFSET_STRIDE'th JEntry and
+ * a length in the rest.  This results in reasonably compressible data (as
+ * long as the stride isn't too small).  We may have to examine as many as
+ * JB_OFFSET_STRIDE JEntrys in order to find out the offset or length of any
+ * given item, but that's still O(1) no matter how large the container is.
+ *
+ * We could avoid eating a flag bit for this purpose if we were to store
+ * the stride in the container header, or if we were willing to treat the
+ * stride as an unchangeable constant.  Neither of those options is very
+ * attractive though.
+ */
+typedef uint32 JEntry;
+
+#define JENTRY_OFFLENMASK		0x0FFFFFFF
+#define JENTRY_TYPEMASK			0x70000000
+#define JENTRY_HAS_OFF			0x80000000
+
+/* values stored in the type bits */
+#define JENTRY_ISSTRING			0x00000000
+#define JENTRY_ISNUMERIC		0x10000000
+#define JENTRY_ISBOOL_FALSE		0x20000000
+#define JENTRY_ISBOOL_TRUE		0x30000000
+#define JENTRY_ISNULL			0x40000000
+#define JENTRY_ISCONTAINER		0x50000000	/* array or object */
+
+/* Access macros.  Note possible multiple evaluations */
+#define JBE_OFFLENFLD(je_)		((je_) & JENTRY_OFFLENMASK)
+#define JBE_HAS_OFF(je_)		(((je_) & JENTRY_HAS_OFF) != 0)
+#define JBE_ISSTRING(je_)		(((je_) & JENTRY_TYPEMASK) == JENTRY_ISSTRING)
+#define JBE_ISNUMERIC(je_)		(((je_) & JENTRY_TYPEMASK) == JENTRY_ISNUMERIC)
+#define JBE_ISCONTAINER(je_)	(((je_) & JENTRY_TYPEMASK) == JENTRY_ISCONTAINER)
+#define JBE_ISNULL(je_)			(((je_) & JENTRY_TYPEMASK) == JENTRY_ISNULL)
+#define JBE_ISBOOL_TRUE(je_)	(((je_) & JENTRY_TYPEMASK) == JENTRY_ISBOOL_TRUE)
+#define JBE_ISBOOL_FALSE(je_)	(((je_) & JENTRY_TYPEMASK) == JENTRY_ISBOOL_FALSE)
+#define JBE_ISBOOL(je_)			(JBE_ISBOOL_TRUE(je_) || JBE_ISBOOL_FALSE(je_))
+
+/* Macro for advancing an offset variable to the next JEntry */
+#define JBE_ADVANCE_OFFSET(offset, je) \
+	do { \
+		JEntry	je_ = (je); \
+		if (JBE_HAS_OFF(je_)) \
+			(offset) = JBE_OFFLENFLD(je_); \
+		else \
+			(offset) += JBE_OFFLENFLD(je_); \
+	} while(0)
+
+/*
+ * We store an offset, not a length, every JB_OFFSET_STRIDE children.
+ * Caution: this macro should only be referenced when creating a JSONB
+ * value.  When examining an existing value, pay attention to the HAS_OFF
+ * bits instead.  This allows changes in the offset-placement heuristic
+ * without breaking on-disk compatibility.
+ */
+#define JB_OFFSET_STRIDE		32
+
+/*
+ * A jsonb array or object node, within a Jsonb Datum.
+ *
+ * An array has one child for each element, stored in array order.
+ *
+ * An object has two children for each key/value pair.  The keys all appear
+ * first, in key sort order; then the values appear, in an order matching the
+ * key order.  This arrangement keeps the keys compact in memory, making a
+ * search for a particular key more cache-friendly.
+ */
+typedef struct JsonbContainer
+{
+	uint32		header;			/* number of elements or key/value pairs, and
+								 * flags */
+	JEntry		children[FLEXIBLE_ARRAY_MEMBER];
+
+	/* the data for each child node follows. */
+} JsonbContainer;
+
+/* flags for the header-field in JsonbContainer */
+#define JB_CMASK				0x0FFFFFFF	/* mask for count field */
+#define JB_FSCALAR				0x10000000	/* flag bits */
+#define JB_FOBJECT				0x20000000
+#define JB_FARRAY				0x40000000
+
+/* convenience macros for accessing a JsonbContainer struct */
+#define JsonContainerSize(jc)		((jc)->header & JB_CMASK)
+#define JsonContainerIsScalar(jc)	(((jc)->header & JB_FSCALAR) != 0)
+#define JsonContainerIsObject(jc)	(((jc)->header & JB_FOBJECT) != 0)
+#define JsonContainerIsArray(jc)	(((jc)->header & JB_FARRAY) != 0)
+
+/* The top-level on-disk format for a jsonb datum. */
+typedef struct
+{
+	int32		vl_len_;		/* varlena header (do not touch directly!) */
+	JsonbContainer root;
+} Jsonb;
+
+/* convenience macros for accessing the root container in a Jsonb datum */
+#define JB_ROOT_COUNT(jbp_)		(*(uint32 *) VARDATA(jbp_) & JB_CMASK)
+#define JB_ROOT_IS_SCALAR(jbp_) ((*(uint32 *) VARDATA(jbp_) & JB_FSCALAR) != 0)
+#define JB_ROOT_IS_OBJECT(jbp_) ((*(uint32 *) VARDATA(jbp_) & JB_FOBJECT) != 0)
+#define JB_ROOT_IS_ARRAY(jbp_)	((*(uint32 *) VARDATA(jbp_) & JB_FARRAY) != 0)
+
+
+enum jbvType
+{
+	/* Scalar types */
+	jbvNull = 0x0,
+	jbvString,
+	jbvNumeric,
+	jbvBool,
+	/* Composite types */
+	jbvArray = 0x10,
+	jbvObject,
+	/* Binary (i.e. struct Jsonb) jbvArray/jbvObject */
+	jbvBinary,
+
+	/*
+	 * Virtual types.
+	 *
+	 * These types are used only for in-memory JSON processing and serialized
+	 * into JSON strings when outputted to json/jsonb.
+	 */
+	jbvDatetime = 0x20,
+};
+
+/*
+ * JsonbValue:	In-memory representation of Jsonb.  This is a convenient
+ * deserialized representation, that can easily support using the "val"
+ * union across underlying types during manipulation.  The Jsonb on-disk
+ * representation has various alignment considerations.
+ */
+struct JsonbValue
+{
+	enum jbvType type;			/* Influences sort order */
+
+	union
+	{
+		Numeric numeric;
+		bool		boolean;
+		struct
+		{
+			int			len;
+			char	   *val;	/* Not necessarily null-terminated */
+		}			string;		/* String primitive type */
+
+		struct
+		{
+			int			nElems;
+			JsonbValue *elems;
+			bool		rawScalar;	/* Top-level "raw scalar" array? */
+		}			array;		/* Array container type */
+
+		struct
+		{
+			int			nPairs; /* 1 pair, 2 elements */
+			JsonbPair  *pairs;
+		}			object;		/* Associative container type */
+
+		struct
+		{
+			int			len;
+			JsonbContainer *data;
+		}			binary;		/* Array or object, in on-disk format */
+
+		struct
+		{
+			Datum		value;
+			Oid			typid;
+			int32		typmod;
+			int			tz;		/* Numeric time zone, in seconds, for
+								 * TimestampTz data type */
+		}			datetime;
+	}			val;
+};
+
+#define IsAJsonbScalar(jsonbval)	(((jsonbval)->type >= jbvNull && \
+									  (jsonbval)->type <= jbvBool) || \
+									  (jsonbval)->type == jbvDatetime)
+
+/*
+ * Key/value pair within an Object.
+ *
+ * This struct type is only used briefly while constructing a Jsonb; it is
+ * *not* the on-disk representation.
+ *
+ * Pairs with duplicate keys are de-duplicated.  We store the originally
+ * observed pair ordering for the purpose of removing duplicates in a
+ * well-defined way (which is "last observed wins").
+ */
+struct JsonbPair
+{
+	JsonbValue	key;			/* Must be a jbvString */
+	JsonbValue	value;			/* May be of any type */
+	uint32		order;			/* Pair's index in original sequence */
+};
+
+/* Conversion state used when parsing Jsonb from text, or for type coercion */
+typedef struct JsonbParseState
+{
+	JsonbValue	contVal;
+	Size		size;
+	struct JsonbParseState *next;
+} JsonbParseState;
+
+/*
+ * JsonbIterator holds details of the type for each iteration. It also stores a
+ * Jsonb varlena buffer, which can be directly accessed in some contexts.
+ */
+typedef enum
+{
+	JBI_ARRAY_START,
+	JBI_ARRAY_ELEM,
+	JBI_OBJECT_START,
+	JBI_OBJECT_KEY,
+	JBI_OBJECT_VALUE
+} JsonbIterState;
+
+typedef struct JsonbIterator
+{
+	/* Container being iterated */
+	JsonbContainer *container;
+	uint32		nElems;			/* Number of elements in children array (will
+								 * be nPairs for objects) */
+	bool		isScalar;		/* Pseudo-array scalar value? */
+	JEntry	   *children;		/* JEntrys for child nodes */
+	/* Data proper.  This points to the beginning of the variable-length data */
+	char	   *dataProper;
+
+	/* Current item in buffer (up to nElems) */
+	int			curIndex;
+
+	/* Data offset corresponding to current item */
+	uint32		curDataOffset;
+
+	/*
+	 * If the container is an object, we want to return keys and values
+	 * alternately; so curDataOffset points to the current key, and
+	 * curValueOffset points to the current value.
+	 */
+	uint32		curValueOffset;
+
+	/* Private state */
+	JsonbIterState state;
+
+	struct JsonbIterator *parent;
+} JsonbIterator;
+
+
+/* Support functions */
+extern uint32 getJsonbOffset(const JsonbContainer *jc, int index);
+extern uint32 getJsonbLength(const JsonbContainer *jc, int index);
+extern int	compareJsonbContainers(JsonbContainer *a, JsonbContainer *b);
+extern JsonbValue *findJsonbValueFromContainer(JsonbContainer *sheader,
+											   uint32 flags,
+											   JsonbValue *key);
+extern JsonbValue *getKeyJsonValueFromContainer(JsonbContainer *container,
+												const char *keyVal, int keyLen,
+												JsonbValue *res);
+extern JsonbValue *getIthJsonbValueFromContainer(JsonbContainer *sheader,
+												 uint32 i);
+extern JsonbValue *pushJsonbValue(JsonbParseState **pstate,
+								  JsonbIteratorToken seq, JsonbValue *jbval);
+extern JsonbIterator *JsonbIteratorInit(JsonbContainer *container);
+extern JsonbIteratorToken JsonbIteratorNext(JsonbIterator **it, JsonbValue *val,
+											bool skipNested);
+extern void JsonbToJsonbValue(Jsonb *jsonb, JsonbValue *val);
+extern Jsonb *JsonbValueToJsonb(JsonbValue *val);
+extern bool JsonbDeepContains(JsonbIterator **val,
+							  JsonbIterator **mContained);
+extern void JsonbHashScalarValue(const JsonbValue *scalarVal, uint32 *hash);
+extern void JsonbHashScalarValueExtended(const JsonbValue *scalarVal,
+										 uint64 *hash, uint64 seed);
+
+/* jsonb.c support functions */
+extern char *JsonbToCString(StringInfo out, JsonbContainer *in,
+							int estimated_len);
+extern char *JsonbToCStringIndent(StringInfo out, JsonbContainer *in,
+								  int estimated_len);
+extern bool JsonbExtractScalar(JsonbContainer *jbc, JsonbValue *res);
+extern const char *JsonbTypeName(JsonbValue *jb);
+
+extern Datum jsonb_set_element(Jsonb *jb, Datum *path, int path_len,
+							   JsonbValue *newval);
+extern Datum jsonb_get_element(Jsonb *jb, Datum *path, int npath,
+							   bool *isnull, bool as_text);
+#endif							/* __JSONB_H__ */