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Add the json_each(JSON,PATH) table-valued-function.

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FossilOrigin-Name: 3335ac17bbcb09dc915173d69bf42048f84ad563
This commit is contained in:
drh 2015-08-19 22:47:17 +00:00
parent 222cd5bee2
commit cb6c6c6f45
3 changed files with 283 additions and 8 deletions
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277
ext/misc/json.c
View File

@ -17,7 +17,9 @@
**
** For the time being, all JSON is stored as pure text. (We might add
** a JSONB type in the future which stores a binary encoding of JSON in
** a BLOB, but there is no support for JSONB in the current implementation.)
** a BLOB, but there is no support for JSONB in the current implementation.
** This implementation parses JSON text at 250 MB/s, so it is hard to see
** how JSONB might improve on that.)
*/
#include "sqlite3ext.h"
SQLITE_EXTENSION_INIT1
@ -1156,6 +1158,276 @@ static void jsonTypeFunc(
sqlite3_free(x.aNode);
}
/****************************************************************************
** The json_each virtual table
****************************************************************************/
typedef struct JsonEachCursor JsonEachCursor;
struct JsonEachCursor {
sqlite3_vtab_cursor base; /* Base class - must be first */
u32 iRowid; /* The rowid */
u32 i; /* Index in sParse.aNode[] of current row */
u32 iEnd; /* EOF when i equals or exceeds this value */
u8 eType; /* Type of top-level element */
char *zJson; /* Input json */
char *zPath; /* Path by which to filter zJson */
JsonParse sParse; /* The input json */
};
/* Constructor for the json_each virtual table */
static int jsonEachConnect(
sqlite3 *db,
void *pAux,
int argc, const char *const*argv,
sqlite3_vtab **ppVtab,
char **pzErr
){
sqlite3_vtab *pNew;
pNew = *ppVtab = sqlite3_malloc( sizeof(*pNew) );
if( pNew==0 ) return SQLITE_NOMEM;
/* Column numbers */
#define JEACH_KEY 0
#define JEACH_VALUE 1
#define JEACH_JSON 2
#define JEACH_PATH 3
sqlite3_declare_vtab(db, "CREATE TABLE x(key,value,json hidden,path hidden)");
memset(pNew, 0, sizeof(*pNew));
return SQLITE_OK;
}
/* destructor for json_each virtual table */
static int jsonEachDisconnect(sqlite3_vtab *pVtab){
sqlite3_free(pVtab);
return SQLITE_OK;
}
/* constructor for a JsonEachCursor object. */
static int jsonEachOpen(sqlite3_vtab *p, sqlite3_vtab_cursor **ppCursor){
JsonEachCursor *pCur;
pCur = sqlite3_malloc( sizeof(*pCur) );
if( pCur==0 ) return SQLITE_NOMEM;
memset(pCur, 0, sizeof(*pCur));
*ppCursor = &pCur->base;
return SQLITE_OK;
}
/* Reset a JsonEachCursor back to its original state. Free any memory
** held. */
static void jsonEachCursorReset(JsonEachCursor *p){
sqlite3_free(p->zJson);
sqlite3_free(p->zPath);
sqlite3_free(p->sParse.aNode);
p->iRowid = 0;
p->i = 0;
p->iEnd = 0;
p->eType = 0;
memset(&p->sParse, 0, sizeof(p->sParse));
p->zJson = 0;
p->zPath = 0;
}
/* Destructor for a jsonEachCursor object */
static int jsonEachClose(sqlite3_vtab_cursor *cur){
JsonEachCursor *p = (JsonEachCursor*)cur;
jsonEachCursorReset(p);
sqlite3_free(cur);
return SQLITE_OK;
}
/* Return TRUE if the jsonEachCursor object has been advanced off the end
** of the JSON object */
static int jsonEachEof(sqlite3_vtab_cursor *cur){
JsonEachCursor *p = (JsonEachCursor*)cur;
return p->i >= p->iEnd;
}
/* Advance the cursor to the next top-level element of the current
** JSON string */
static int jsonEachNext(sqlite3_vtab_cursor *cur){
JsonEachCursor *p = (JsonEachCursor*)cur;
switch( p->eType ){
case JSON_ARRAY: {
p->i += jsonSize(&p->sParse.aNode[p->i]);
p->iRowid++;
break;
}
case JSON_OBJECT: {
p->i += 1 + jsonSize(&p->sParse.aNode[p->i+1]);
p->iRowid++;
break;
}
default: {
p->i = p->iEnd;
break;
}
}
return SQLITE_OK;
}
/* Return the value of a column */
static int jsonEachColumn(
sqlite3_vtab_cursor *cur, /* The cursor */
sqlite3_context *ctx, /* First argument to sqlite3_result_...() */
int i /* Which column to return */
){
JsonEachCursor *p = (JsonEachCursor*)cur;
switch( i ){
case JEACH_KEY: {
if( p->eType==JSON_OBJECT ){
jsonReturn(&p->sParse.aNode[p->i], ctx, 0);
}else{
sqlite3_result_int64(ctx, p->iRowid);
}
break;
}
case JEACH_VALUE: {
if( p->eType==JSON_OBJECT ){
jsonReturn(&p->sParse.aNode[p->i+1], ctx, 0);
}else{
jsonReturn(&p->sParse.aNode[p->i], ctx, 0);
}
break;
}
case JEACH_PATH: {
const char *zPath = p->zPath;
if( zPath==0 ) zPath = "$";
sqlite3_result_text(ctx, zPath, -1, SQLITE_STATIC);
break;
}
default: {
sqlite3_result_text(ctx, p->sParse.zJson, -1, SQLITE_STATIC);
break;
}
}
return SQLITE_OK;
}
/* Return the current rowid value */
static int jsonEachRowid(sqlite3_vtab_cursor *cur, sqlite_int64 *pRowid){
JsonEachCursor *p = (JsonEachCursor*)cur;
*pRowid = p->iRowid;
return SQLITE_OK;
}
/* The query strategy is to look for an equality constraint on the json
** column. Without such a constraint, the table cannot operate. idxNum is
** 1 if the constraint is found, 3 if the constraint and zPath are found,
** and 0 otherwise.
*/
static int jsonEachBestIndex(
sqlite3_vtab *tab,
sqlite3_index_info *pIdxInfo
){
int i;
int jsonIdx = -1;
int pathIdx = -1;
const struct sqlite3_index_constraint *pConstraint;
pConstraint = pIdxInfo->aConstraint;
for(i=0; i<pIdxInfo->nConstraint; i++, pConstraint++){
if( pConstraint->usable==0 ) continue;
if( pConstraint->op!=SQLITE_INDEX_CONSTRAINT_EQ ) continue;
switch( pConstraint->iColumn ){
case JEACH_JSON: jsonIdx = i; break;
case JEACH_PATH: pathIdx = i; break;
default: /* no-op */ break;
}
}
if( jsonIdx<0 ){
pIdxInfo->idxNum = 0;
pIdxInfo->estimatedCost = (double)2000000000;
}else{
pIdxInfo->estimatedCost = (double)1;
pIdxInfo->aConstraintUsage[jsonIdx].argvIndex = 1;
pIdxInfo->aConstraintUsage[jsonIdx].omit = 1;
if( pathIdx<0 ){
pIdxInfo->idxNum = 1;
}else{
pIdxInfo->aConstraintUsage[pathIdx].argvIndex = 2;
pIdxInfo->aConstraintUsage[pathIdx].omit = 1;
pIdxInfo->idxNum = 3;
}
}
return SQLITE_OK;
}
/* Start a search on a new JSON string */
static int jsonEachFilter(
sqlite3_vtab_cursor *cur,
int idxNum, const char *idxStr,
int argc, sqlite3_value **argv
){
JsonEachCursor *p = (JsonEachCursor*)cur;
const char *z;
const char *zPath;
sqlite3_int64 n;
jsonEachCursorReset(p);
if( idxNum==0 ) return SQLITE_OK;
z = (const char*)sqlite3_value_text(argv[0]);
if( z==0 ) return SQLITE_OK;
if( idxNum&2 ){
zPath = (const char*)sqlite3_value_text(argv[1]);
if( zPath==0 || zPath[0]!='$' ) return SQLITE_OK;
}
n = sqlite3_value_bytes(argv[0]);
p->zJson = sqlite3_malloc( n+1 );
if( p->zJson==0 ) return SQLITE_NOMEM;
memcpy(p->zJson, z, n+1);
if( jsonParse(&p->sParse, p->zJson) ){
jsonEachCursorReset(p);
}else{
JsonNode *pNode;
if( idxNum==3 ){
n = sqlite3_value_bytes(argv[1]);
p->zPath = sqlite3_malloc( n+1 );
if( p->zPath==0 ) return SQLITE_NOMEM;
memcpy(p->zPath, zPath, n+1);
pNode = jsonLookup(&p->sParse, 0, p->zPath+1, 0);
if( pNode==0 ){
jsonEachCursorReset(p);
return SQLITE_OK;
}
}else{
pNode = p->sParse.aNode;
}
p->i = (int)(pNode - p->sParse.aNode);
p->eType = pNode->eType;
if( p->eType>=JSON_ARRAY ){
p->i++;
p->iEnd = p->i + pNode->n;
}else{
p->iEnd = p->i+1;
}
}
return SQLITE_OK;
}
/* The methods of the json_each virtual table */
static sqlite3_module jsonEachModule = {
0, /* iVersion */
0, /* xCreate */
jsonEachConnect, /* xConnect */
jsonEachBestIndex, /* xBestIndex */
jsonEachDisconnect, /* xDisconnect */
0, /* xDestroy */
jsonEachOpen, /* xOpen - open a cursor */
jsonEachClose, /* xClose - close a cursor */
jsonEachFilter, /* xFilter - configure scan constraints */
jsonEachNext, /* xNext - advance a cursor */
jsonEachEof, /* xEof - check for end of scan */
jsonEachColumn, /* xColumn - read data */
jsonEachRowid, /* xRowid - read data */
0, /* xUpdate */
0, /* xBegin */
0, /* xSync */
0, /* xCommit */
0, /* xRollback */
0, /* xFindMethod */
0, /* xRename */
};
#ifdef _WIN32
__declspec(dllexport)
#endif
@ -1199,5 +1471,8 @@ int sqlite3_json_init(
(void*)&aFunc[i].flag,
aFunc[i].xFunc, 0, 0);
}
if( rc==SQLITE_OK ){
rc = sqlite3_create_module(db, "json_each", &jsonEachModule, 0);
}
return rc;
}

12
manifest
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@ -1,5 +1,5 @@
C Merge\sthe\stable-valued-function\srowid\sfix.
D 2015-08-19T19:26:13.526
C Add\sthe\sjson_each(JSON,PATH)\stable-valued-function.
D 2015-08-19T22:47:17.476
F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
F Makefile.in 90f3097efb9a53f5fc59a4f8a08be07cf9f52c02
F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@ -192,7 +192,7 @@ F ext/misc/eval.c f971962e92ebb8b0a4e6b62949463ee454d88fa2
F ext/misc/fileio.c d4171c815d6543a9edef8308aab2951413cd8d0f
F ext/misc/fuzzer.c 4c84635c71c26cfa7c2e5848cf49fe2d2cfcd767
F ext/misc/ieee754.c b0362167289170627659e84173f5d2e8fee8566e
F ext/misc/json.c 3b265167a9f8f006042bf0226a838c773a098c03
F ext/misc/json.c 57a9f747b2813edc5f481eb808889d304a1c5f79
F ext/misc/nextchar.c 35c8b8baacb96d92abbb34a83a997b797075b342
F ext/misc/percentile.c bcbee3c061b884eccb80e21651daaae8e1e43c63
F ext/misc/regexp.c af92cdaa5058fcec1451e49becc7ba44dba023dc
@ -1378,7 +1378,7 @@ F tool/vdbe_profile.tcl 67746953071a9f8f2f668b73fe899074e2c6d8c1
F tool/warnings-clang.sh f6aa929dc20ef1f856af04a730772f59283631d4
F tool/warnings.sh 48bd54594752d5be3337f12c72f28d2080cb630b
F tool/win/sqlite.vsix deb315d026cc8400325c5863eef847784a219a2f
P 96a5d44d9fcb7b159c04630ad2d956fe27df5a43 a325a08599759471047e234ef9cfcc3cb110aafd
R dcfe96af8a1b65c426e62b553bd60db8
P a06a6392bd48baa8b9bac2624869c0cc7da7e779
R 43d8c9f353202a0c5a0252660436f9ac
U drh
Z 00eb910bc67976561bafd5a76ff4be3d
Z 41b78b71d0425818407424da18ee9720

2
manifest.uuid
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@ -1 +1 @@
a06a6392bd48baa8b9bac2624869c0cc7da7e779
3335ac17bbcb09dc915173d69bf42048f84ad563