mirror of
https://github.com/ncruces/go-sqlite3.git
synced 2026-01-11 21:49:13 +00:00
Towards virtual tables.
This commit is contained in:
Nuno Cruces
202
vtab.go
202
vtab.go
@@ -189,20 +189,10 @@ type VTabCursor interface {
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// https://sqlite.org/c3ref/index_info.html
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type IndexInfo struct {
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/* Inputs */
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Constraint []struct {
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Column int
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Op IndexConstraintOp
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Usable bool
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}
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OrderBy []struct {
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Column int
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Desc bool
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}
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Constraint []IndexConstraint
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OrderBy []IndexOrderBy
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/* Outputs */
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ConstraintUsage []struct {
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ArgvIndex int
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Omit bool
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}
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ConstraintUsage []IndexConstraintUsage
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IdxNum int
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IdxStr string
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IdxFlags IndexScanFlag
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@@ -212,6 +202,85 @@ type IndexInfo struct {
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ColumnsUsed int64
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}
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// An IndexConstraint describes virtual table indexing constraint information.
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//
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// https://sqlite.org/c3ref/index_info.html
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type IndexConstraint struct {
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Column int
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Op IndexConstraintOp
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Usable bool
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}
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// An IndexOrderBy describes virtual table indexing order by information.
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//
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// https://sqlite.org/c3ref/index_info.html
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type IndexOrderBy struct {
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Column int
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Desc bool
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}
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// An IndexConstraintUsage describes how virtual table indexing constraints will be used.
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//
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// https://sqlite.org/c3ref/index_info.html
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type IndexConstraintUsage struct {
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ArgvIndex int
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Omit bool
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}
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func (idx *IndexInfo) load(ctx context.Context, mod api.Module, ptr uint32) {
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// https://sqlite.org/c3ref/index_info.html
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idx.Constraint = make([]IndexConstraint, util.ReadUint32(mod, ptr+0))
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idx.ConstraintUsage = make([]IndexConstraintUsage, util.ReadUint32(mod, ptr+0))
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idx.OrderBy = make([]IndexOrderBy, util.ReadUint32(mod, ptr+8))
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constraintPtr := util.ReadUint32(mod, ptr+4)
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for i := range idx.Constraint {
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idx.Constraint[i] = IndexConstraint{
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Column: int(util.ReadUint32(mod, constraintPtr+0)),
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Op: IndexConstraintOp(util.ReadUint8(mod, constraintPtr+4)),
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Usable: util.ReadUint8(mod, constraintPtr+8) != 0,
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}
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constraintPtr += 12
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}
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orderByPtr := util.ReadUint32(mod, ptr+12)
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for i := range idx.OrderBy {
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idx.OrderBy[i] = IndexOrderBy{
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Column: int(util.ReadUint32(mod, orderByPtr+0)),
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Desc: util.ReadUint8(mod, orderByPtr+4) != 0,
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}
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orderByPtr += 8
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}
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}
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func (idx *IndexInfo) save(ctx context.Context, mod api.Module, ptr uint32) {
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// https://sqlite.org/c3ref/index_info.html
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usagePtr := util.ReadUint32(mod, ptr+16)
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for _, usage := range idx.ConstraintUsage {
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util.WriteUint32(mod, usagePtr+0, uint32(usage.ArgvIndex))
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if usage.Omit {
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util.WriteUint8(mod, usagePtr+4, 1)
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}
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usagePtr += 8
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}
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util.WriteUint32(mod, ptr+20, uint32(idx.IdxNum))
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if idx.IdxStr != "" {
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conn := ctx.Value(connKey{}).(*Conn)
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util.WriteUint32(mod, ptr+24, conn.newString(idx.IdxStr))
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util.WriteUint32(mod, ptr+28, 1)
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}
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if idx.OrderByConsumed {
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util.WriteUint32(mod, ptr+32, 1)
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}
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util.WriteFloat64(mod, ptr+40, idx.EstimatedCost)
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util.WriteUint64(mod, ptr+48, uint64(idx.EstimatedRows))
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util.WriteUint32(mod, ptr+56, uint32(idx.IdxFlags))
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util.WriteUint64(mod, ptr+64, uint64(idx.ColumnsUsed))
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}
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// IndexConstraintOp is a virtual table constraint operator code.
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//
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// https://sqlite.org/c3ref/c_index_constraint_eq.html
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@@ -240,83 +309,108 @@ const (
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// IndexScanFlag is a virtual table scan flag.
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//
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// https://www.sqlite.org/c3ref/c_index_scan_unique.html
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type IndexScanFlag uint8
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type IndexScanFlag uint32
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const (
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Unique IndexScanFlag = 1
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)
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func vtabConnectCallback(ctx context.Context, mod api.Module, pMod, argc, argv, ppVTab, pzErr uint32) uint32 {
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const handleOffset = 4
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handle := util.ReadUint32(mod, pMod-handleOffset)
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module := util.GetHandle(ctx, handle)
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db := ctx.Value(connKey{}).(*Conn)
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func vtabReflectCallback(name string) func(_ context.Context, _ api.Module, _, _, _, _, _ uint32) uint32 {
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return func(ctx context.Context, mod api.Module, pMod, argc, argv, ppVTab, pzErr uint32) uint32 {
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module := vtabGetHandle(ctx, mod, pMod)
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db := ctx.Value(connKey{}).(*Conn)
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arg := make([]reflect.Value, 1+argc)
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arg[0] = reflect.ValueOf(db)
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arg := make([]reflect.Value, 1+argc)
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arg[0] = reflect.ValueOf(db)
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for i := uint32(0); i < argc; i++ {
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ptr := util.ReadUint32(mod, argv+i*ptrlen)
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arg[i+1] = reflect.ValueOf(util.ReadString(mod, ptr, _MAX_STRING))
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for i := uint32(0); i < argc; i++ {
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ptr := util.ReadUint32(mod, argv+i*ptrlen)
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arg[i+1] = reflect.ValueOf(util.ReadString(mod, ptr, _MAX_STRING))
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}
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res := reflect.ValueOf(module).MethodByName(name).Call(arg)
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err, _ := res[1].Interface().(error)
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if err == nil {
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vtabPutHandle(ctx, mod, ppVTab, res[0].Interface())
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return _OK
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}
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// TODO: error message?
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return errorCode(err, ERROR)
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}
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res := reflect.ValueOf(module).MethodByName("Connect").Call(arg)
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err, _ := res[1].Interface().(error)
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if err == nil {
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handle := util.AddHandle(ctx, res[0].Interface())
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ptr := util.ReadUint32(mod, ppVTab)
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util.WriteUint32(mod, ptr-handleOffset, handle)
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return _OK
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}
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// TODO: error message
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return errorCode(err, ERROR)
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}
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func vtabBestIndexCallback(ctx context.Context, mod api.Module, pVTab, pIdxInfo uint32) uint32 {
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const handleOffset = 4
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handle := util.ReadUint32(mod, pVTab-handleOffset)
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vtab := util.GetHandle(ctx, handle).(VTab)
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_ = vtab
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return 1
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}
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func vtabDisconnectCallback(ctx context.Context, mod api.Module, pVTab uint32) uint32 {
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return 1
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vtab := vtabGetHandle(ctx, mod, pVTab).(VTab)
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err := vtab.Disconnect()
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// TODO: error message?
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return errorCode(err, _OK)
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}
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func vtabDestroyCallback(ctx context.Context, mod api.Module, pVTab uint32) uint32 {
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vtab := vtabGetHandle(ctx, mod, pVTab).(VTabDestroyer)
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err := vtab.Destroy()
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// TODO: error message?
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return errorCode(err, _OK)
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}
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func vtabBestIndexCallback(ctx context.Context, mod api.Module, pVTab, pIdxInfo uint32) uint32 {
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var info IndexInfo
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info.load(ctx, mod, pIdxInfo)
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vtab := vtabGetHandle(ctx, mod, pVTab).(VTab)
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err := vtab.BestIndex(&info)
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info.save(ctx, mod, pIdxInfo)
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// TODO: error message?
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return errorCode(err, _OK)
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}
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func vtabIntegrityCallback(ctx context.Context, mod api.Module, pVTab, zSchema, zTabName, mFlags, pzErr uint32) uint32 {
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return 1
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return uint32(ERROR)
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}
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func vtabCallbackI(ctx context.Context, mod api.Module, _ uint32) uint32 {
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return 1
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return uint32(ERROR)
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}
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func vtabCallbackII(ctx context.Context, mod api.Module, _, _ uint32) uint32 {
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return 1
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return uint32(ERROR)
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}
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func vtabCallbackIIII(ctx context.Context, mod api.Module, _, _, _, _ uint32) uint32 {
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return 1
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return uint32(ERROR)
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}
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func cursorOpenCallback(ctx context.Context, mod api.Module, pVTab, ppCur uint32) uint32 {
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return 1
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return uint32(ERROR)
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}
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func cursorFilterCallback(ctx context.Context, mod api.Module, pCur, idxNum, idxStr, argc, argv uint32) uint32 {
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return 1
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return uint32(ERROR)
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}
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func cursorColumnCallback(ctx context.Context, mod api.Module, pCur, pCtx, n uint32) uint32 {
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return 1
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return uint32(ERROR)
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}
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func cursorRowidCallback(ctx context.Context, mod api.Module, pCur, pRowid uint32) uint32 {
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return 1
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return uint32(ERROR)
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}
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func cursorCallbackI(ctx context.Context, mod api.Module, _ uint32) uint32 {
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return 1
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return uint32(ERROR)
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}
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func vtabGetHandle(ctx context.Context, mod api.Module, ptr uint32) any {
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const handleOffset = 4
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handle := util.ReadUint32(mod, ptr-handleOffset)
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return util.GetHandle(ctx, handle)
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}
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func vtabPutHandle(ctx context.Context, mod api.Module, pptr uint32, val any) {
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const handleOffset = 4
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handle := util.AddHandle(ctx, val)
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ptr := util.ReadUint32(mod, pptr)
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util.WriteUint32(mod, ptr-handleOffset, handle)
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}
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