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diff --git a/ext/misc/qpvtab.c b/ext/misc/qpvtab.c
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+/*
+** 2022-01-19
+**
+** The author disclaims copyright to this source code. In place of
+** a legal notice, here is a blessing:
+**
+** May you do good and not evil.
+** May you find forgiveness for yourself and forgive others.
+** May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file implements a virtual-table that returns information about
+** how the query planner called the xBestIndex method. This virtual table
+** is intended for testing and debugging only.
+**
+** The schema of the virtual table is this:
+**
+** CREATE TABLE qpvtab(
+** vn TEXT, -- Name of an sqlite3_index_info field
+** ix INTEGER, -- Array index or value
+** cn TEXT, -- Column name
+** op INTEGER, -- operator
+** ux BOOLEAN, -- "usable" field
+** rhs TEXT, -- sqlite3_vtab_rhs_value()
+**
+** a, b, c, d, e, -- Extra columns to attach constraints to
+**
+** flags INTEGER HIDDEN -- control flags
+** );
+**
+** The virtual table returns a description of the sqlite3_index_info object
+** that was provided to the (successful) xBestIndex method. There is one
+** row in the result table for each field in the sqlite3_index_info object.
+**
+** The values of the "a" through "e" columns are one of:
+**
+** 1. TEXT - the same as the column name
+** 2. INTEGER - 1 for "a", 2 for "b", and so forth
+**
+** Option 1 is the default behavior. 2 is use if there is a usable
+** constraint on "flags" with an integer right-hand side that where the
+** value of the right-hand side has its 0x001 bit set.
+**
+** All constraints on columns "a" through "e" are marked as "omit".
+**
+** If there is a usable constraint on "flags" that has a RHS value that
+** is an integer and that integer has its 0x02 bit set, then the
+** orderByConsumed flag is set.
+**
+** FLAGS SUMMARY:
+**
+** 0x001 Columns 'a' through 'e' have INT values
+** 0x002 orderByConsumed is set
+** 0x004 OFFSET and LIMIT have omit set
+**
+** COMPILE:
+**
+** gcc -Wall -g -shared -fPIC -I. qpvtab.c -o qqvtab.so
+**
+** EXAMPLE USAGE:
+**
+** .load ./qpvtab
+** SELECT rowid, *, flags FROM qpvtab(102)
+** WHERE a=19
+** AND b BETWEEN 4.5 and 'hello'
+** AND c<>x'aabbcc'
+** ORDER BY d, e DESC;
+*/
+#if !defined(SQLITEINT_H)
+#include "sqlite3ext.h"
+#endif
+SQLITE_EXTENSION_INIT1
+#include <string.h>
+#include <assert.h>
+#include <stdlib.h>
+
+#if !defined(SQLITE_OMIT_VIRTUALTABLE)
+
+/* qpvtab_vtab is a subclass of sqlite3_vtab which is
+** underlying representation of the virtual table
+*/
+typedef struct qpvtab_vtab qpvtab_vtab;
+struct qpvtab_vtab {
+ sqlite3_vtab base; /* Base class - must be first */
+};
+
+/* qpvtab_cursor is a subclass of sqlite3_vtab_cursor which will
+** serve as the underlying representation of a cursor that scans
+** over rows of the result
+*/
+typedef struct qpvtab_cursor qpvtab_cursor;
+struct qpvtab_cursor {
+ sqlite3_vtab_cursor base; /* Base class - must be first */
+ sqlite3_int64 iRowid; /* The rowid */
+ const char *zData; /* Data to return */
+ int nData; /* Number of bytes of data */
+ int flags; /* Flags value */
+};
+
+/*
+** Names of columns
+*/
+static const char *azColname[] = {
+ "vn",
+ "ix",
+ "cn",
+ "op",
+ "ux",
+ "rhs",
+ "a", "b", "c", "d", "e",
+ "flags",
+ ""
+};
+
+/*
+** The qpvtabConnect() method is invoked to create a new
+** qpvtab virtual table.
+*/
+static int qpvtabConnect(
+ sqlite3 *db,
+ void *pAux,
+ int argc, const char *const*argv,
+ sqlite3_vtab **ppVtab,
+ char **pzErr
+){
+ qpvtab_vtab *pNew;
+ int rc;
+
+ rc = sqlite3_declare_vtab(db,
+ "CREATE TABLE x("
+ " vn TEXT,"
+ " ix INT,"
+ " cn TEXT,"
+ " op INT,"
+ " ux BOOLEAN,"
+ " rhs TEXT,"
+ " a, b, c, d, e,"
+ " flags INT HIDDEN)"
+ );
+#define QPVTAB_VN 0
+#define QPVTAB_IX 1
+#define QPVTAB_CN 2
+#define QPVTAB_OP 3
+#define QPVTAB_UX 4
+#define QPVTAB_RHS 5
+#define QPVTAB_A 6
+#define QPVTAB_B 7
+#define QPVTAB_C 8
+#define QPVTAB_D 9
+#define QPVTAB_E 10
+#define QPVTAB_FLAGS 11
+#define QPVTAB_NONE 12
+ if( rc==SQLITE_OK ){
+ pNew = sqlite3_malloc( sizeof(*pNew) );
+ *ppVtab = (sqlite3_vtab*)pNew;
+ if( pNew==0 ) return SQLITE_NOMEM;
+ memset(pNew, 0, sizeof(*pNew));
+ }
+ return rc;
+}
+
+/*
+** This method is the destructor for qpvtab_vtab objects.
+*/
+static int qpvtabDisconnect(sqlite3_vtab *pVtab){
+ qpvtab_vtab *p = (qpvtab_vtab*)pVtab;
+ sqlite3_free(p);
+ return SQLITE_OK;
+}
+
+/*
+** Constructor for a new qpvtab_cursor object.
+*/
+static int qpvtabOpen(sqlite3_vtab *p, sqlite3_vtab_cursor **ppCursor){
+ qpvtab_cursor *pCur;
+ pCur = sqlite3_malloc( sizeof(*pCur) );
+ if( pCur==0 ) return SQLITE_NOMEM;
+ memset(pCur, 0, sizeof(*pCur));
+ *ppCursor = &pCur->base;
+ return SQLITE_OK;
+}
+
+/*
+** Destructor for a qpvtab_cursor.
+*/
+static int qpvtabClose(sqlite3_vtab_cursor *cur){
+ qpvtab_cursor *pCur = (qpvtab_cursor*)cur;
+ sqlite3_free(pCur);
+ return SQLITE_OK;
+}
+
+
+/*
+** Advance a qpvtab_cursor to its next row of output.
+*/
+static int qpvtabNext(sqlite3_vtab_cursor *cur){
+ qpvtab_cursor *pCur = (qpvtab_cursor*)cur;
+ if( pCur->iRowid<pCur->nData ){
+ const char *z = &pCur->zData[pCur->iRowid];
+ const char *zEnd = strchr(z, '\n');
+ if( zEnd ) zEnd++;
+ pCur->iRowid = (int)(zEnd - pCur->zData);
+ }
+ return SQLITE_OK;
+}
+
+/*
+** Return values of columns for the row at which the qpvtab_cursor
+** is currently pointing.
+*/
+static int qpvtabColumn(
+ sqlite3_vtab_cursor *cur, /* The cursor */
+ sqlite3_context *ctx, /* First argument to sqlite3_result_...() */
+ int i /* Which column to return */
+){
+ qpvtab_cursor *pCur = (qpvtab_cursor*)cur;
+ if( i>=QPVTAB_VN && i<=QPVTAB_RHS && pCur->iRowid<pCur->nData ){
+ const char *z = &pCur->zData[pCur->iRowid];
+ const char *zEnd;
+ int j;
+ j = QPVTAB_VN;
+ while(1){
+ zEnd = strchr(z, j==QPVTAB_RHS ? '\n' : ',');
+ if( j==i || zEnd==0 ) break;
+ z = zEnd+1;
+ j++;
+ }
+ if( zEnd==z ){
+ sqlite3_result_null(ctx);
+ }else if( i==QPVTAB_IX || i==QPVTAB_OP || i==QPVTAB_UX ){
+ sqlite3_result_int(ctx, atoi(z));
+ }else{
+ sqlite3_result_text64(ctx, z, zEnd-z, SQLITE_TRANSIENT, SQLITE_UTF8);
+ }
+ }else if( i>=QPVTAB_A && i<=QPVTAB_E ){
+ if( pCur->flags & 0x001 ){
+ sqlite3_result_int(ctx, i-QPVTAB_A+1);
+ }else{
+ char x = 'a'+i-QPVTAB_A;
+ sqlite3_result_text64(ctx, &x, 1, SQLITE_TRANSIENT, SQLITE_UTF8);
+ }
+ }else if( i==QPVTAB_FLAGS ){
+ sqlite3_result_int(ctx, pCur->flags);
+ }
+ return SQLITE_OK;
+}
+
+/*
+** Return the rowid for the current row. In this implementation, the
+** rowid is the same as the output value.
+*/
+static int qpvtabRowid(sqlite3_vtab_cursor *cur, sqlite_int64 *pRowid){
+ qpvtab_cursor *pCur = (qpvtab_cursor*)cur;
+ *pRowid = pCur->iRowid;
+ return SQLITE_OK;
+}
+
+/*
+** Return TRUE if the cursor has been moved off of the last
+** row of output.
+*/
+static int qpvtabEof(sqlite3_vtab_cursor *cur){
+ qpvtab_cursor *pCur = (qpvtab_cursor*)cur;
+ return pCur->iRowid>=pCur->nData;
+}
+
+/*
+** This method is called to "rewind" the qpvtab_cursor object back
+** to the first row of output. This method is always called at least
+** once prior to any call to qpvtabColumn() or qpvtabRowid() or
+** qpvtabEof().
+*/
+static int qpvtabFilter(
+ sqlite3_vtab_cursor *pVtabCursor,
+ int idxNum, const char *idxStr,
+ int argc, sqlite3_value **argv
+){
+ qpvtab_cursor *pCur = (qpvtab_cursor *)pVtabCursor;
+ pCur->iRowid = 0;
+ pCur->zData = idxStr;
+ pCur->nData = (int)strlen(idxStr);
+ pCur->flags = idxNum;
+ return SQLITE_OK;
+}
+
+/*
+** Append the text of a value to pStr
+*/
+static void qpvtabStrAppendValue(
+ sqlite3_str *pStr,
+ sqlite3_value *pVal
+){
+ switch( sqlite3_value_type(pVal) ){
+ case SQLITE_NULL:
+ sqlite3_str_appendf(pStr, "NULL");
+ break;
+ case SQLITE_INTEGER:
+ sqlite3_str_appendf(pStr, "%lld", sqlite3_value_int64(pVal));
+ break;
+ case SQLITE_FLOAT:
+ sqlite3_str_appendf(pStr, "%!f", sqlite3_value_double(pVal));
+ break;
+ case SQLITE_TEXT: {
+ int i;
+ const char *a = (const char*)sqlite3_value_text(pVal);
+ int n = sqlite3_value_bytes(pVal);
+ sqlite3_str_append(pStr, "'", 1);
+ for(i=0; i<n; i++){
+ char c = a[i];
+ if( c=='\n' ) c = ' ';
+ sqlite3_str_append(pStr, &c, 1);
+ if( c=='\'' ) sqlite3_str_append(pStr, &c, 1);
+ }
+ sqlite3_str_append(pStr, "'", 1);
+ break;
+ }
+ case SQLITE_BLOB: {
+ int i;
+ const unsigned char *a = sqlite3_value_blob(pVal);
+ int n = sqlite3_value_bytes(pVal);
+ sqlite3_str_append(pStr, "x'", 2);
+ for(i=0; i<n; i++){
+ sqlite3_str_appendf(pStr, "%02x", a[i]);
+ }
+ sqlite3_str_append(pStr, "'", 1);
+ break;
+ }
+ }
+}
+
+/*
+** SQLite will invoke this method one or more times while planning a query
+** that uses the virtual table. This routine needs to create
+** a query plan for each invocation and compute an estimated cost for that
+** plan.
+*/
+static int qpvtabBestIndex(
+ sqlite3_vtab *tab,
+ sqlite3_index_info *pIdxInfo
+){
+ sqlite3_str *pStr = sqlite3_str_new(0);
+ int i, k = 0;
+ int rc;
+ sqlite3_str_appendf(pStr, "nConstraint,%d,,,,\n", pIdxInfo->nConstraint);
+ for(i=0; i<pIdxInfo->nConstraint; i++){
+ sqlite3_value *pVal;
+ int iCol = pIdxInfo->aConstraint[i].iColumn;
+ int op = pIdxInfo->aConstraint[i].op;
+ if( iCol==QPVTAB_FLAGS && pIdxInfo->aConstraint[i].usable ){
+ pVal = 0;
+ rc = sqlite3_vtab_rhs_value(pIdxInfo, i, &pVal);
+ assert( rc==SQLITE_OK || pVal==0 );
+ if( pVal ){
+ pIdxInfo->idxNum = sqlite3_value_int(pVal);
+ if( pIdxInfo->idxNum & 0x002 ) pIdxInfo->orderByConsumed = 1;
+ }
+ }
+ if( op==SQLITE_INDEX_CONSTRAINT_LIMIT
+ || op==SQLITE_INDEX_CONSTRAINT_OFFSET
+ ){
+ iCol = QPVTAB_NONE;
+ }
+ sqlite3_str_appendf(pStr,"aConstraint,%d,%s,%d,%d,",
+ i,
+ azColname[iCol],
+ op,
+ pIdxInfo->aConstraint[i].usable);
+ pVal = 0;
+ rc = sqlite3_vtab_rhs_value(pIdxInfo, i, &pVal);
+ assert( rc==SQLITE_OK || pVal==0 );
+ if( pVal ){
+ qpvtabStrAppendValue(pStr, pVal);
+ }
+ sqlite3_str_append(pStr, "\n", 1);
+ }
+ for(i=0; i<pIdxInfo->nConstraint; i++){
+ int iCol = pIdxInfo->aConstraint[i].iColumn;
+ int op = pIdxInfo->aConstraint[i].op;
+ if( op==SQLITE_INDEX_CONSTRAINT_LIMIT
+ || op==SQLITE_INDEX_CONSTRAINT_OFFSET
+ ){
+ iCol = QPVTAB_NONE;
+ }
+ if( iCol>=QPVTAB_A && pIdxInfo->aConstraint[i].usable ){
+ pIdxInfo->aConstraintUsage[i].argvIndex = ++k;
+ if( iCol<=QPVTAB_FLAGS || (pIdxInfo->idxNum & 0x004)!=0 ){
+ pIdxInfo->aConstraintUsage[i].omit = 1;
+ }
+ }
+ }
+ sqlite3_str_appendf(pStr, "nOrderBy,%d,,,,\n", pIdxInfo->nOrderBy);
+ for(i=0; i<pIdxInfo->nOrderBy; i++){
+ int iCol = pIdxInfo->aOrderBy[i].iColumn;
+ sqlite3_str_appendf(pStr, "aOrderBy,%d,%s,%d,,\n",i,
+ iCol>=0 ? azColname[iCol] : "rowid",
+ pIdxInfo->aOrderBy[i].desc
+ );
+ }
+ sqlite3_str_appendf(pStr, "sqlite3_vtab_distinct,%d,,,,\n",
+ sqlite3_vtab_distinct(pIdxInfo));
+ sqlite3_str_appendf(pStr, "idxFlags,%d,,,,\n", pIdxInfo->idxFlags);
+ sqlite3_str_appendf(pStr, "colUsed,%d,,,,\n", (int)pIdxInfo->colUsed);
+ pIdxInfo->estimatedCost = (double)10;
+ pIdxInfo->estimatedRows = 10;
+ sqlite3_str_appendf(pStr, "idxNum,%d,,,,\n", pIdxInfo->idxNum);
+ sqlite3_str_appendf(pStr, "orderByConsumed,%d,,,,\n",
+ pIdxInfo->orderByConsumed);
+ pIdxInfo->idxStr = sqlite3_str_finish(pStr);
+ pIdxInfo->needToFreeIdxStr = 1;
+ return SQLITE_OK;
+}
+
+/*
+** This following structure defines all the methods for the
+** virtual table.
+*/
+static sqlite3_module qpvtabModule = {
+ /* iVersion */ 0,
+ /* xCreate */ 0,
+ /* xConnect */ qpvtabConnect,
+ /* xBestIndex */ qpvtabBestIndex,
+ /* xDisconnect */ qpvtabDisconnect,
+ /* xDestroy */ 0,
+ /* xOpen */ qpvtabOpen,
+ /* xClose */ qpvtabClose,
+ /* xFilter */ qpvtabFilter,
+ /* xNext */ qpvtabNext,
+ /* xEof */ qpvtabEof,
+ /* xColumn */ qpvtabColumn,
+ /* xRowid */ qpvtabRowid,
+ /* xUpdate */ 0,
+ /* xBegin */ 0,
+ /* xSync */ 0,
+ /* xCommit */ 0,
+ /* xRollback */ 0,
+ /* xFindMethod */ 0,
+ /* xRename */ 0,
+ /* xSavepoint */ 0,
+ /* xRelease */ 0,
+ /* xRollbackTo */ 0,
+ /* xShadowName */ 0
+};
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+
+#ifdef _WIN32
+__declspec(dllexport)
+#endif
+int sqlite3_qpvtab_init(
+ sqlite3 *db,
+ char **pzErrMsg,
+ const sqlite3_api_routines *pApi
+){
+ int rc = SQLITE_OK;
+ SQLITE_EXTENSION_INIT2(pApi);
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+ rc = sqlite3_create_module(db, "qpvtab", &qpvtabModule, 0);
+#endif
+ return rc;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-26 08:21:02 +0000