diff options
Diffstat (limited to 'src/backend/utils/adt/jsonpath_exec.c')
-rw-r--r-- | src/backend/utils/adt/jsonpath_exec.c | 436 |
1 files changed, 436 insertions, 0 deletions
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c index 7811fa31e07..c55b3aae027 100644 --- a/src/backend/utils/adt/jsonpath_exec.c +++ b/src/backend/utils/adt/jsonpath_exec.c @@ -61,9 +61,11 @@ #include "catalog/pg_collation.h" #include "catalog/pg_type.h" +#include "executor/execExpr.h" #include "funcapi.h" #include "lib/stringinfo.h" #include "miscadmin.h" +#include "nodes/nodeFuncs.h" #include "regex/regex.h" #include "utils/builtins.h" #include "utils/date.h" @@ -74,6 +76,8 @@ #include "utils/guc.h" #include "utils/json.h" #include "utils/jsonpath.h" +#include "utils/lsyscache.h" +#include "utils/memutils.h" #include "utils/timestamp.h" #include "utils/varlena.h" @@ -155,6 +159,57 @@ typedef struct JsonValueListIterator ListCell *next; } JsonValueListIterator; +/* Structures for JSON_TABLE execution */ +typedef struct JsonTableScanState JsonTableScanState; +typedef struct JsonTableJoinState JsonTableJoinState; + +struct JsonTableScanState +{ + JsonTableScanState *parent; + JsonTableJoinState *nested; + MemoryContext mcxt; + JsonPath *path; + List *args; + JsonValueList found; + JsonValueListIterator iter; + Datum current; + int ordinal; + bool currentIsNull; + bool errorOnError; + bool advanceNested; + bool reset; +}; + +struct JsonTableJoinState +{ + union + { + struct + { + JsonTableJoinState *left; + JsonTableJoinState *right; + bool advanceRight; + } join; + JsonTableScanState scan; + } u; + bool is_join; +}; + +/* random number to identify JsonTableContext */ +#define JSON_TABLE_CONTEXT_MAGIC 418352867 + +typedef struct JsonTableContext +{ + int magic; + struct + { + ExprState *expr; + JsonTableScanState *scan; + } *colexprs; + JsonTableScanState root; + bool empty; +} JsonTableContext; + /* strict/lax flags is decomposed into four [un]wrap/error flags */ #define jspStrictAbsenseOfErrors(cxt) (!(cxt)->laxMode) #define jspAutoUnwrap(cxt) ((cxt)->laxMode) @@ -245,6 +300,7 @@ static JsonPathExecResult getArrayIndex(JsonPathExecContext *cxt, JsonPathItem *jsp, JsonbValue *jb, int32 *index); static JsonBaseObjectInfo setBaseObject(JsonPathExecContext *cxt, JsonbValue *jbv, int32 id); +static void JsonValueListClear(JsonValueList *jvl); static void JsonValueListAppend(JsonValueList *jvl, JsonbValue *jbv); static int JsonValueListLength(const JsonValueList *jvl); static bool JsonValueListIsEmpty(JsonValueList *jvl); @@ -262,6 +318,12 @@ static JsonbValue *wrapItemsInArray(const JsonValueList *items); static int compareDatetime(Datum val1, Oid typid1, Datum val2, Oid typid2, bool useTz, bool *have_error); + +static JsonTableJoinState *JsonTableInitPlanState(JsonTableContext *cxt, + Node *plan, JsonTableScanState *parent); +static bool JsonTableNextRow(JsonTableScanState *scan); + + /****************** User interface to JsonPath executor ********************/ /* @@ -2459,6 +2521,13 @@ setBaseObject(JsonPathExecContext *cxt, JsonbValue *jbv, int32 id) } static void +JsonValueListClear(JsonValueList *jvl) +{ + jvl->singleton = NULL; + jvl->list = NULL; +} + +static void JsonValueListAppend(JsonValueList *jvl, JsonbValue *jbv) { if (jvl->singleton) @@ -3067,3 +3136,370 @@ JsonItemFromDatum(Datum val, Oid typid, int32 typmod, JsonbValue *res) "casted to supported jsonpath types."))); } } + +/************************ JSON_TABLE functions ***************************/ + +/* + * Returns private data from executor state. Ensure validity by check with + * MAGIC number. + */ +static inline JsonTableContext * +GetJsonTableContext(TableFuncScanState *state, const char *fname) +{ + JsonTableContext *result; + + if (!IsA(state, TableFuncScanState)) + elog(ERROR, "%s called with invalid TableFuncScanState", fname); + result = (JsonTableContext *) state->opaque; + if (result->magic != JSON_TABLE_CONTEXT_MAGIC) + elog(ERROR, "%s called with invalid TableFuncScanState", fname); + + return result; +} + +/* Recursively initialize JSON_TABLE scan state */ +static void +JsonTableInitScanState(JsonTableContext *cxt, JsonTableScanState *scan, + JsonTableParent *node, JsonTableScanState *parent, + List *args, MemoryContext mcxt) +{ + int i; + + scan->parent = parent; + scan->errorOnError = node->errorOnError; + scan->path = DatumGetJsonPathP(node->path->constvalue); + scan->args = args; + scan->mcxt = AllocSetContextCreate(mcxt, "JsonTableContext", + ALLOCSET_DEFAULT_SIZES); + scan->nested = node->child ? + JsonTableInitPlanState(cxt, node->child, scan) : NULL; + scan->current = PointerGetDatum(NULL); + scan->currentIsNull = true; + + for (i = node->colMin; i <= node->colMax; i++) + cxt->colexprs[i].scan = scan; +} + +/* Recursively initialize JSON_TABLE scan state */ +static JsonTableJoinState * +JsonTableInitPlanState(JsonTableContext *cxt, Node *plan, + JsonTableScanState *parent) +{ + JsonTableJoinState *state = palloc0(sizeof(*state)); + + if (IsA(plan, JsonTableSibling)) + { + JsonTableSibling *join = castNode(JsonTableSibling, plan); + + state->is_join = true; + state->u.join.left = JsonTableInitPlanState(cxt, join->larg, parent); + state->u.join.right = JsonTableInitPlanState(cxt, join->rarg, parent); + } + else + { + JsonTableParent *node = castNode(JsonTableParent, plan); + + state->is_join = false; + + JsonTableInitScanState(cxt, &state->u.scan, node, parent, + parent->args, parent->mcxt); + } + + return state; +} + +/* + * JsonTableInitOpaque + * Fill in TableFuncScanState->opaque for JsonTable processor + */ +static void +JsonTableInitOpaque(TableFuncScanState *state, int natts) +{ + JsonTableContext *cxt; + PlanState *ps = &state->ss.ps; + TableFuncScan *tfs = castNode(TableFuncScan, ps->plan); + TableFunc *tf = tfs->tablefunc; + JsonExpr *ci = castNode(JsonExpr, tf->docexpr); + JsonTableParent *root = castNode(JsonTableParent, tf->plan); + List *args = NIL; + ListCell *lc; + int i; + + cxt = palloc0(sizeof(JsonTableContext)); + cxt->magic = JSON_TABLE_CONTEXT_MAGIC; + + if (ci->passing_values) + { + ListCell *exprlc; + ListCell *namelc; + + forboth(exprlc, ci->passing_values, + namelc, ci->passing_names) + { + Expr *expr = (Expr *) lfirst(exprlc); + String *name = lfirst_node(String, namelc); + JsonPathVariableEvalContext *var = palloc(sizeof(*var)); + + var->name = pstrdup(name->sval); + var->typid = exprType((Node *) expr); + var->typmod = exprTypmod((Node *) expr); + var->estate = ExecInitExpr(expr, ps); + var->econtext = ps->ps_ExprContext; + var->mcxt = CurrentMemoryContext; + var->evaluated = false; + var->value = (Datum) 0; + var->isnull = true; + + args = lappend(args, var); + } + } + + cxt->colexprs = palloc(sizeof(*cxt->colexprs) * + list_length(tf->colvalexprs)); + + JsonTableInitScanState(cxt, &cxt->root, root, NULL, args, + CurrentMemoryContext); + + i = 0; + + foreach(lc, tf->colvalexprs) + { + Expr *expr = lfirst(lc); + + cxt->colexprs[i].expr = + ExecInitExprWithCaseValue(expr, ps, + &cxt->colexprs[i].scan->current, + &cxt->colexprs[i].scan->currentIsNull); + + i++; + } + + state->opaque = cxt; +} + +/* Reset scan iterator to the beginning of the item list */ +static void +JsonTableRescan(JsonTableScanState *scan) +{ + JsonValueListInitIterator(&scan->found, &scan->iter); + scan->current = PointerGetDatum(NULL); + scan->currentIsNull = true; + scan->advanceNested = false; + scan->ordinal = 0; +} + +/* Reset context item of a scan, execute JSON path and reset a scan */ +static void +JsonTableResetContextItem(JsonTableScanState *scan, Datum item) +{ + MemoryContext oldcxt; + JsonPathExecResult res; + Jsonb *js = (Jsonb *) DatumGetJsonbP(item); + + JsonValueListClear(&scan->found); + + MemoryContextResetOnly(scan->mcxt); + + oldcxt = MemoryContextSwitchTo(scan->mcxt); + + res = executeJsonPath(scan->path, scan->args, EvalJsonPathVar, js, + scan->errorOnError, &scan->found, false /* FIXME */); + + MemoryContextSwitchTo(oldcxt); + + if (jperIsError(res)) + { + Assert(!scan->errorOnError); + JsonValueListClear(&scan->found); /* EMPTY ON ERROR case */ + } + + JsonTableRescan(scan); +} + +/* + * JsonTableSetDocument + * Install the input document + */ +static void +JsonTableSetDocument(TableFuncScanState *state, Datum value) +{ + JsonTableContext *cxt = GetJsonTableContext(state, "JsonTableSetDocument"); + + JsonTableResetContextItem(&cxt->root, value); +} + +/* + * Fetch next row from a union joined scan. + * + * Returns false at the end of a scan, true otherwise. + */ +static bool +JsonTableNextJoinRow(JsonTableJoinState *state) +{ + if (!state->is_join) + return JsonTableNextRow(&state->u.scan); + + if (!state->u.join.advanceRight) + { + /* fetch next outer row */ + if (JsonTableNextJoinRow(state->u.join.left)) + return true; + + state->u.join.advanceRight = true; /* next inner row */ + } + + /* fetch next inner row */ + return JsonTableNextJoinRow(state->u.join.right); +} + +/* Recursively set 'reset' flag of scan and its child nodes */ +static void +JsonTableJoinReset(JsonTableJoinState *state) +{ + if (state->is_join) + { + JsonTableJoinReset(state->u.join.left); + JsonTableJoinReset(state->u.join.right); + state->u.join.advanceRight = false; + } + else + { + state->u.scan.reset = true; + state->u.scan.advanceNested = false; + + if (state->u.scan.nested) + JsonTableJoinReset(state->u.scan.nested); + } +} + +/* + * Fetch next row from a simple scan with outer joined nested subscans. + * + * Returns false at the end of a scan, true otherwise. + */ +static bool +JsonTableNextRow(JsonTableScanState *scan) +{ + JsonbValue *jbv; + MemoryContext oldcxt; + + /* reset context item if requested */ + if (scan->reset) + { + Assert(!scan->parent->currentIsNull); + JsonTableResetContextItem(scan, scan->parent->current); + scan->reset = false; + } + + if (scan->advanceNested) + { + /* fetch next nested row */ + if (JsonTableNextJoinRow(scan->nested)) + return true; + + scan->advanceNested = false; + } + + /* fetch next row */ + jbv = JsonValueListNext(&scan->found, &scan->iter); + + if (!jbv) + { + scan->current = PointerGetDatum(NULL); + scan->currentIsNull = true; + return false; /* end of scan */ + } + + /* set current row item */ + oldcxt = MemoryContextSwitchTo(scan->mcxt); + scan->current = JsonbPGetDatum(JsonbValueToJsonb(jbv)); + scan->currentIsNull = false; + MemoryContextSwitchTo(oldcxt); + + scan->ordinal++; + + if (scan->nested) + { + JsonTableJoinReset(scan->nested); + scan->advanceNested = JsonTableNextJoinRow(scan->nested); + } + + return true; +} + +/* + * JsonTableFetchRow + * Prepare the next "current" tuple for upcoming GetValue calls. + * Returns FALSE if the row-filter expression returned no more rows. + */ +static bool +JsonTableFetchRow(TableFuncScanState *state) +{ + JsonTableContext *cxt = GetJsonTableContext(state, "JsonTableFetchRow"); + + if (cxt->empty) + return false; + + return JsonTableNextRow(&cxt->root); +} + +/* + * JsonTableGetValue + * Return the value for column number 'colnum' for the current row. + * + * This leaks memory, so be sure to reset often the context in which it's + * called. + */ +static Datum +JsonTableGetValue(TableFuncScanState *state, int colnum, + Oid typid, int32 typmod, bool *isnull) +{ + JsonTableContext *cxt = GetJsonTableContext(state, "JsonTableGetValue"); + ExprContext *econtext = state->ss.ps.ps_ExprContext; + ExprState *estate = cxt->colexprs[colnum].expr; + JsonTableScanState *scan = cxt->colexprs[colnum].scan; + Datum result; + + if (scan->currentIsNull) /* NULL from outer/union join */ + { + result = (Datum) 0; + *isnull = true; + } + else if (estate) /* regular column */ + { + result = ExecEvalExpr(estate, econtext, isnull); + } + else + { + result = Int32GetDatum(scan->ordinal); /* ordinality column */ + *isnull = false; + } + + return result; +} + +/* + * JsonTableDestroyOpaque + */ +static void +JsonTableDestroyOpaque(TableFuncScanState *state) +{ + JsonTableContext *cxt = GetJsonTableContext(state, "JsonTableDestroyOpaque"); + + /* not valid anymore */ + cxt->magic = 0; + + state->opaque = NULL; +} + +const TableFuncRoutine JsonbTableRoutine = +{ + JsonTableInitOpaque, + JsonTableSetDocument, + NULL, + NULL, + NULL, + JsonTableFetchRow, + JsonTableGetValue, + JsonTableDestroyOpaque +}; |