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gotosocial/vendor/github.com/ncruces/go-sqlite3/vtab.go

664 lines
20 KiB
Go

package sqlite3
import (
"context"
"reflect"
"github.com/ncruces/go-sqlite3/internal/util"
"github.com/tetratelabs/wazero/api"
)
// CreateModule registers a new virtual table module name.
// If create is nil, the virtual table is eponymous.
//
// https://sqlite.org/c3ref/create_module.html
func CreateModule[T VTab](db *Conn, name string, create, connect VTabConstructor[T]) error {
var flags int
const (
VTAB_CREATOR = 0x01
VTAB_DESTROYER = 0x02
VTAB_UPDATER = 0x04
VTAB_RENAMER = 0x08
VTAB_OVERLOADER = 0x10
VTAB_CHECKER = 0x20
VTAB_TXN = 0x40
VTAB_SAVEPOINTER = 0x80
)
if create != nil {
flags |= VTAB_CREATOR
}
vtab := reflect.TypeOf(connect).Out(0)
if implements[VTabDestroyer](vtab) {
flags |= VTAB_DESTROYER
}
if implements[VTabUpdater](vtab) {
flags |= VTAB_UPDATER
}
if implements[VTabRenamer](vtab) {
flags |= VTAB_RENAMER
}
if implements[VTabOverloader](vtab) {
flags |= VTAB_OVERLOADER
}
if implements[VTabChecker](vtab) {
flags |= VTAB_CHECKER
}
if implements[VTabTxn](vtab) {
flags |= VTAB_TXN
}
if implements[VTabSavepointer](vtab) {
flags |= VTAB_SAVEPOINTER
}
defer db.arena.mark()()
namePtr := db.arena.string(name)
modulePtr := util.AddHandle(db.ctx, module[T]{create, connect})
r := db.call("sqlite3_create_module_go", uint64(db.handle),
uint64(namePtr), uint64(flags), uint64(modulePtr))
return db.error(r)
}
func implements[T any](typ reflect.Type) bool {
var ptr *T
return typ.Implements(reflect.TypeOf(ptr).Elem())
}
// DeclareVTab declares the schema of a virtual table.
//
// https://sqlite.org/c3ref/declare_vtab.html
func (c *Conn) DeclareVTab(sql string) error {
defer c.arena.mark()()
sqlPtr := c.arena.string(sql)
r := c.call("sqlite3_declare_vtab", uint64(c.handle), uint64(sqlPtr))
return c.error(r)
}
// VTabConflictMode is a virtual table conflict resolution mode.
//
// https://sqlite.org/c3ref/c_fail.html
type VTabConflictMode uint8
const (
VTAB_ROLLBACK VTabConflictMode = 1
VTAB_IGNORE VTabConflictMode = 2
VTAB_FAIL VTabConflictMode = 3
VTAB_ABORT VTabConflictMode = 4
VTAB_REPLACE VTabConflictMode = 5
)
// VTabOnConflict determines the virtual table conflict policy.
//
// https://sqlite.org/c3ref/vtab_on_conflict.html
func (c *Conn) VTabOnConflict() VTabConflictMode {
r := c.call("sqlite3_vtab_on_conflict", uint64(c.handle))
return VTabConflictMode(r)
}
// VTabConfigOption is a virtual table configuration option.
//
// https://sqlite.org/c3ref/c_vtab_constraint_support.html
type VTabConfigOption uint8
const (
VTAB_CONSTRAINT_SUPPORT VTabConfigOption = 1
VTAB_INNOCUOUS VTabConfigOption = 2
VTAB_DIRECTONLY VTabConfigOption = 3
VTAB_USES_ALL_SCHEMAS VTabConfigOption = 4
)
// VTabConfig configures various facets of the virtual table interface.
//
// https://sqlite.org/c3ref/vtab_config.html
func (c *Conn) VTabConfig(op VTabConfigOption, args ...any) error {
var i uint64
if op == VTAB_CONSTRAINT_SUPPORT && len(args) > 0 {
if b, ok := args[0].(bool); ok && b {
i = 1
}
}
r := c.call("sqlite3_vtab_config_go", uint64(c.handle), uint64(op), i)
return c.error(r)
}
// VTabConstructor is a virtual table constructor function.
type VTabConstructor[T VTab] func(db *Conn, module, schema, table string, arg ...string) (T, error)
type module[T VTab] [2]VTabConstructor[T]
type vtabConstructor int
const (
xCreate vtabConstructor = 0
xConnect vtabConstructor = 1
)
// A VTab describes a particular instance of the virtual table.
// A VTab may optionally implement [io.Closer] to free resources.
//
// https://sqlite.org/c3ref/vtab.html
type VTab interface {
// https://sqlite.org/vtab.html#xbestindex
BestIndex(*IndexInfo) error
// https://sqlite.org/vtab.html#xopen
Open() (VTabCursor, error)
}
// A VTabDestroyer allows a virtual table to drop persistent state.
type VTabDestroyer interface {
VTab
// https://sqlite.org/vtab.html#sqlite3_module.xDestroy
Destroy() error
}
// A VTabUpdater allows a virtual table to be updated.
type VTabUpdater interface {
VTab
// https://sqlite.org/vtab.html#xupdate
Update(arg ...Value) (rowid int64, err error)
}
// A VTabRenamer allows a virtual table to be renamed.
type VTabRenamer interface {
VTab
// https://sqlite.org/vtab.html#xrename
Rename(new string) error
}
// A VTabOverloader allows a virtual table to overload SQL functions.
type VTabOverloader interface {
VTab
// https://sqlite.org/vtab.html#xfindfunction
FindFunction(arg int, name string) (ScalarFunction, IndexConstraintOp)
}
// A VTabChecker allows a virtual table to report errors
// to the PRAGMA integrity_check and PRAGMA quick_check commands.
//
// Integrity should return an error if it finds problems in the content of the virtual table,
// but should avoid returning a (wrapped) [Error], [ErrorCode] or [ExtendedErrorCode],
// as those indicate the Integrity method itself encountered problems
// while trying to evaluate the virtual table content.
type VTabChecker interface {
VTab
// https://sqlite.org/vtab.html#xintegrity
Integrity(schema, table string, flags int) error
}
// A VTabTxn allows a virtual table to implement
// transactions with two-phase commit.
//
// Anything that is required as part of a commit that may fail
// should be performed in the Sync() callback.
// Current versions of SQLite ignore any errors
// returned by Commit() and Rollback().
type VTabTxn interface {
VTab
// https://sqlite.org/vtab.html#xBegin
Begin() error
// https://sqlite.org/vtab.html#xsync
Sync() error
// https://sqlite.org/vtab.html#xcommit
Commit() error
// https://sqlite.org/vtab.html#xrollback
Rollback() error
}
// A VTabSavepointer allows a virtual table to implement
// nested transactions.
//
// https://sqlite.org/vtab.html#xsavepoint
type VTabSavepointer interface {
VTabTxn
Savepoint(id int) error
Release(id int) error
RollbackTo(id int) error
}
// A VTabCursor describes cursors that point
// into the virtual table and are used
// to loop through the virtual table.
// A VTabCursor may optionally implement
// [io.Closer] to free resources.
//
// http://sqlite.org/c3ref/vtab_cursor.html
type VTabCursor interface {
// https://sqlite.org/vtab.html#xfilter
Filter(idxNum int, idxStr string, arg ...Value) error
// https://sqlite.org/vtab.html#xnext
Next() error
// https://sqlite.org/vtab.html#xeof
EOF() bool
// https://sqlite.org/vtab.html#xcolumn
Column(ctx *Context, n int) error
// https://sqlite.org/vtab.html#xrowid
RowID() (int64, error)
}
// An IndexInfo describes virtual table indexing information.
//
// https://sqlite.org/c3ref/index_info.html
type IndexInfo struct {
// Inputs
Constraint []IndexConstraint
OrderBy []IndexOrderBy
ColumnsUsed int64
// Outputs
ConstraintUsage []IndexConstraintUsage
IdxNum int
IdxStr string
IdxFlags IndexScanFlag
OrderByConsumed bool
EstimatedCost float64
EstimatedRows int64
// Internal
c *Conn
handle uint32
}
// An IndexConstraint describes virtual table indexing constraint information.
//
// https://sqlite.org/c3ref/index_info.html
type IndexConstraint struct {
Column int
Op IndexConstraintOp
Usable bool
}
// An IndexOrderBy describes virtual table indexing order by information.
//
// https://sqlite.org/c3ref/index_info.html
type IndexOrderBy struct {
Column int
Desc bool
}
// An IndexConstraintUsage describes how virtual table indexing constraints will be used.
//
// https://sqlite.org/c3ref/index_info.html
type IndexConstraintUsage struct {
ArgvIndex int
Omit bool
}
// RHSValue returns the value of the right-hand operand of a constraint
// if the right-hand operand is known.
//
// https://sqlite.org/c3ref/vtab_rhs_value.html
func (idx *IndexInfo) RHSValue(column int) (Value, error) {
defer idx.c.arena.mark()()
valPtr := idx.c.arena.new(ptrlen)
r := idx.c.call("sqlite3_vtab_rhs_value", uint64(idx.handle),
uint64(column), uint64(valPtr))
if err := idx.c.error(r); err != nil {
return Value{}, err
}
return Value{
c: idx.c,
handle: util.ReadUint32(idx.c.mod, valPtr),
}, nil
}
// Collation returns the name of the collation for a virtual table constraint.
//
// https://sqlite.org/c3ref/vtab_collation.html
func (idx *IndexInfo) Collation(column int) string {
r := idx.c.call("sqlite3_vtab_collation", uint64(idx.handle),
uint64(column))
return util.ReadString(idx.c.mod, uint32(r), _MAX_NAME)
}
// Distinct determines if a virtual table query is DISTINCT.
//
// https://sqlite.org/c3ref/vtab_distinct.html
func (idx *IndexInfo) Distinct() int {
r := idx.c.call("sqlite3_vtab_distinct", uint64(idx.handle))
return int(r)
}
// In identifies and handles IN constraints.
//
// https://sqlite.org/c3ref/vtab_in.html
func (idx *IndexInfo) In(column, handle int) bool {
r := idx.c.call("sqlite3_vtab_in", uint64(idx.handle),
uint64(column), uint64(handle))
return r != 0
}
func (idx *IndexInfo) load() {
// https://sqlite.org/c3ref/index_info.html
mod := idx.c.mod
ptr := idx.handle
idx.Constraint = make([]IndexConstraint, util.ReadUint32(mod, ptr+0))
idx.ConstraintUsage = make([]IndexConstraintUsage, util.ReadUint32(mod, ptr+0))
idx.OrderBy = make([]IndexOrderBy, util.ReadUint32(mod, ptr+8))
constraintPtr := util.ReadUint32(mod, ptr+4)
for i := range idx.Constraint {
idx.Constraint[i] = IndexConstraint{
Column: int(int32(util.ReadUint32(mod, constraintPtr+0))),
Op: IndexConstraintOp(util.ReadUint8(mod, constraintPtr+4)),
Usable: util.ReadUint8(mod, constraintPtr+5) != 0,
}
constraintPtr += 12
}
orderByPtr := util.ReadUint32(mod, ptr+12)
for i := range idx.OrderBy {
idx.OrderBy[i] = IndexOrderBy{
Column: int(int32(util.ReadUint32(mod, orderByPtr+0))),
Desc: util.ReadUint8(mod, orderByPtr+4) != 0,
}
orderByPtr += 8
}
idx.EstimatedCost = util.ReadFloat64(mod, ptr+40)
idx.EstimatedRows = int64(util.ReadUint64(mod, ptr+48))
idx.ColumnsUsed = int64(util.ReadUint64(mod, ptr+64))
}
func (idx *IndexInfo) save() {
// https://sqlite.org/c3ref/index_info.html
mod := idx.c.mod
ptr := idx.handle
usagePtr := util.ReadUint32(mod, ptr+16)
for _, usage := range idx.ConstraintUsage {
util.WriteUint32(mod, usagePtr+0, uint32(usage.ArgvIndex))
if usage.Omit {
util.WriteUint8(mod, usagePtr+4, 1)
}
usagePtr += 8
}
util.WriteUint32(mod, ptr+20, uint32(idx.IdxNum))
if idx.IdxStr != "" {
util.WriteUint32(mod, ptr+24, idx.c.newString(idx.IdxStr))
util.WriteUint32(mod, ptr+28, 1) // needToFreeIdxStr
}
if idx.OrderByConsumed {
util.WriteUint32(mod, ptr+32, 1)
}
util.WriteFloat64(mod, ptr+40, idx.EstimatedCost)
util.WriteUint64(mod, ptr+48, uint64(idx.EstimatedRows))
util.WriteUint32(mod, ptr+56, uint32(idx.IdxFlags))
}
// IndexConstraintOp is a virtual table constraint operator code.
//
// https://sqlite.org/c3ref/c_index_constraint_eq.html
type IndexConstraintOp uint8
const (
INDEX_CONSTRAINT_EQ IndexConstraintOp = 2
INDEX_CONSTRAINT_GT IndexConstraintOp = 4
INDEX_CONSTRAINT_LE IndexConstraintOp = 8
INDEX_CONSTRAINT_LT IndexConstraintOp = 16
INDEX_CONSTRAINT_GE IndexConstraintOp = 32
INDEX_CONSTRAINT_MATCH IndexConstraintOp = 64
INDEX_CONSTRAINT_LIKE IndexConstraintOp = 65
INDEX_CONSTRAINT_GLOB IndexConstraintOp = 66
INDEX_CONSTRAINT_REGEXP IndexConstraintOp = 67
INDEX_CONSTRAINT_NE IndexConstraintOp = 68
INDEX_CONSTRAINT_ISNOT IndexConstraintOp = 69
INDEX_CONSTRAINT_ISNOTNULL IndexConstraintOp = 70
INDEX_CONSTRAINT_ISNULL IndexConstraintOp = 71
INDEX_CONSTRAINT_IS IndexConstraintOp = 72
INDEX_CONSTRAINT_LIMIT IndexConstraintOp = 73
INDEX_CONSTRAINT_OFFSET IndexConstraintOp = 74
INDEX_CONSTRAINT_FUNCTION IndexConstraintOp = 150
)
// IndexScanFlag is a virtual table scan flag.
//
// https://sqlite.org/c3ref/c_index_scan_unique.html
type IndexScanFlag uint32
const (
INDEX_SCAN_UNIQUE IndexScanFlag = 1
)
func vtabModuleCallback(i vtabConstructor) func(_ context.Context, _ api.Module, _, _, _, _, _ uint32) uint32 {
return func(ctx context.Context, mod api.Module, pMod, nArg, pArg, ppVTab, pzErr uint32) uint32 {
arg := make([]reflect.Value, 1+nArg)
arg[0] = reflect.ValueOf(ctx.Value(connKey{}))
for i := uint32(0); i < nArg; i++ {
ptr := util.ReadUint32(mod, pArg+i*ptrlen)
arg[i+1] = reflect.ValueOf(util.ReadString(mod, ptr, _MAX_SQL_LENGTH))
}
module := vtabGetHandle(ctx, mod, pMod)
res := reflect.ValueOf(module).Index(int(i)).Call(arg)
err, _ := res[1].Interface().(error)
if err == nil {
vtabPutHandle(ctx, mod, ppVTab, res[0].Interface())
}
return vtabError(ctx, mod, pzErr, _PTR_ERROR, err)
}
}
func vtabDisconnectCallback(ctx context.Context, mod api.Module, pVTab uint32) uint32 {
err := vtabDelHandle(ctx, mod, pVTab)
return vtabError(ctx, mod, 0, _PTR_ERROR, err)
}
func vtabDestroyCallback(ctx context.Context, mod api.Module, pVTab uint32) uint32 {
vtab := vtabGetHandle(ctx, mod, pVTab).(VTabDestroyer)
err := vtab.Destroy()
if cerr := vtabDelHandle(ctx, mod, pVTab); err == nil {
err = cerr
}
return vtabError(ctx, mod, 0, _PTR_ERROR, err)
}
func vtabBestIndexCallback(ctx context.Context, mod api.Module, pVTab, pIdxInfo uint32) uint32 {
var info IndexInfo
info.handle = pIdxInfo
info.c = ctx.Value(connKey{}).(*Conn)
info.load()
vtab := vtabGetHandle(ctx, mod, pVTab).(VTab)
err := vtab.BestIndex(&info)
info.save()
return vtabError(ctx, mod, pVTab, _VTAB_ERROR, err)
}
func vtabUpdateCallback(ctx context.Context, mod api.Module, pVTab, nArg, pArg, pRowID uint32) uint32 {
vtab := vtabGetHandle(ctx, mod, pVTab).(VTabUpdater)
db := ctx.Value(connKey{}).(*Conn)
args := make([]Value, nArg)
callbackArgs(db, args, pArg)
rowID, err := vtab.Update(args...)
if err == nil {
util.WriteUint64(mod, pRowID, uint64(rowID))
}
return vtabError(ctx, mod, pVTab, _VTAB_ERROR, err)
}
func vtabRenameCallback(ctx context.Context, mod api.Module, pVTab, zNew uint32) uint32 {
vtab := vtabGetHandle(ctx, mod, pVTab).(VTabRenamer)
err := vtab.Rename(util.ReadString(mod, zNew, _MAX_NAME))
return vtabError(ctx, mod, pVTab, _VTAB_ERROR, err)
}
func vtabFindFuncCallback(ctx context.Context, mod api.Module, pVTab uint32, nArg int32, zName, pxFunc uint32) uint32 {
vtab := vtabGetHandle(ctx, mod, pVTab).(VTabOverloader)
f, op := vtab.FindFunction(int(nArg), util.ReadString(mod, zName, _MAX_NAME))
if op != 0 {
var wrapper uint32
wrapper = util.AddHandle(ctx, func(c Context, arg ...Value) {
defer util.DelHandle(ctx, wrapper)
f(c, arg...)
})
util.WriteUint32(mod, pxFunc, wrapper)
}
return uint32(op)
}
func vtabIntegrityCallback(ctx context.Context, mod api.Module, pVTab, zSchema, zTabName, mFlags, pzErr uint32) uint32 {
vtab := vtabGetHandle(ctx, mod, pVTab).(VTabChecker)
schema := util.ReadString(mod, zSchema, _MAX_NAME)
table := util.ReadString(mod, zTabName, _MAX_NAME)
err := vtab.Integrity(schema, table, int(mFlags))
// xIntegrity should return OK - even if it finds problems in the content of the virtual table.
// https://sqlite.org/vtab.html#xintegrity
vtabError(ctx, mod, pzErr, _PTR_ERROR, err)
_, code := errorCode(err, _OK)
return code
}
func vtabBeginCallback(ctx context.Context, mod api.Module, pVTab uint32) uint32 {
vtab := vtabGetHandle(ctx, mod, pVTab).(VTabTxn)
err := vtab.Begin()
return vtabError(ctx, mod, pVTab, _VTAB_ERROR, err)
}
func vtabSyncCallback(ctx context.Context, mod api.Module, pVTab uint32) uint32 {
vtab := vtabGetHandle(ctx, mod, pVTab).(VTabTxn)
err := vtab.Sync()
return vtabError(ctx, mod, pVTab, _VTAB_ERROR, err)
}
func vtabCommitCallback(ctx context.Context, mod api.Module, pVTab uint32) uint32 {
vtab := vtabGetHandle(ctx, mod, pVTab).(VTabTxn)
err := vtab.Commit()
return vtabError(ctx, mod, pVTab, _VTAB_ERROR, err)
}
func vtabRollbackCallback(ctx context.Context, mod api.Module, pVTab uint32) uint32 {
vtab := vtabGetHandle(ctx, mod, pVTab).(VTabTxn)
err := vtab.Rollback()
return vtabError(ctx, mod, pVTab, _VTAB_ERROR, err)
}
func vtabSavepointCallback(ctx context.Context, mod api.Module, pVTab uint32, id int32) uint32 {
vtab := vtabGetHandle(ctx, mod, pVTab).(VTabSavepointer)
err := vtab.Savepoint(int(id))
return vtabError(ctx, mod, pVTab, _VTAB_ERROR, err)
}
func vtabReleaseCallback(ctx context.Context, mod api.Module, pVTab uint32, id int32) uint32 {
vtab := vtabGetHandle(ctx, mod, pVTab).(VTabSavepointer)
err := vtab.Release(int(id))
return vtabError(ctx, mod, pVTab, _VTAB_ERROR, err)
}
func vtabRollbackToCallback(ctx context.Context, mod api.Module, pVTab uint32, id int32) uint32 {
vtab := vtabGetHandle(ctx, mod, pVTab).(VTabSavepointer)
err := vtab.RollbackTo(int(id))
return vtabError(ctx, mod, pVTab, _VTAB_ERROR, err)
}
func cursorOpenCallback(ctx context.Context, mod api.Module, pVTab, ppCur uint32) uint32 {
vtab := vtabGetHandle(ctx, mod, pVTab).(VTab)
cursor, err := vtab.Open()
if err == nil {
vtabPutHandle(ctx, mod, ppCur, cursor)
}
return vtabError(ctx, mod, pVTab, _VTAB_ERROR, err)
}
func cursorCloseCallback(ctx context.Context, mod api.Module, pCur uint32) uint32 {
err := vtabDelHandle(ctx, mod, pCur)
return vtabError(ctx, mod, 0, _VTAB_ERROR, err)
}
func cursorFilterCallback(ctx context.Context, mod api.Module, pCur uint32, idxNum int32, idxStr, nArg, pArg uint32) uint32 {
cursor := vtabGetHandle(ctx, mod, pCur).(VTabCursor)
db := ctx.Value(connKey{}).(*Conn)
args := make([]Value, nArg)
callbackArgs(db, args, pArg)
var idxName string
if idxStr != 0 {
idxName = util.ReadString(mod, idxStr, _MAX_LENGTH)
}
err := cursor.Filter(int(idxNum), idxName, args...)
return vtabError(ctx, mod, pCur, _CURSOR_ERROR, err)
}
func cursorEOFCallback(ctx context.Context, mod api.Module, pCur uint32) uint32 {
cursor := vtabGetHandle(ctx, mod, pCur).(VTabCursor)
if cursor.EOF() {
return 1
}
return 0
}
func cursorNextCallback(ctx context.Context, mod api.Module, pCur uint32) uint32 {
cursor := vtabGetHandle(ctx, mod, pCur).(VTabCursor)
err := cursor.Next()
return vtabError(ctx, mod, pCur, _CURSOR_ERROR, err)
}
func cursorColumnCallback(ctx context.Context, mod api.Module, pCur, pCtx uint32, n int32) uint32 {
cursor := vtabGetHandle(ctx, mod, pCur).(VTabCursor)
db := ctx.Value(connKey{}).(*Conn)
err := cursor.Column(&Context{db, pCtx}, int(n))
return vtabError(ctx, mod, pCur, _CURSOR_ERROR, err)
}
func cursorRowIDCallback(ctx context.Context, mod api.Module, pCur, pRowID uint32) uint32 {
cursor := vtabGetHandle(ctx, mod, pCur).(VTabCursor)
rowID, err := cursor.RowID()
if err == nil {
util.WriteUint64(mod, pRowID, uint64(rowID))
}
return vtabError(ctx, mod, pCur, _CURSOR_ERROR, err)
}
const (
_PTR_ERROR = iota
_VTAB_ERROR
_CURSOR_ERROR
)
func vtabError(ctx context.Context, mod api.Module, ptr, kind uint32, err error) uint32 {
const zErrMsgOffset = 8
msg, code := errorCode(err, ERROR)
if msg != "" && ptr != 0 {
switch kind {
case _VTAB_ERROR:
ptr = ptr + zErrMsgOffset // zErrMsg
case _CURSOR_ERROR:
ptr = util.ReadUint32(mod, ptr) + zErrMsgOffset // pVTab->zErrMsg
}
db := ctx.Value(connKey{}).(*Conn)
if ptr := util.ReadUint32(mod, ptr); ptr != 0 {
db.free(ptr)
}
util.WriteUint32(mod, ptr, db.newString(msg))
}
return code
}
func vtabGetHandle(ctx context.Context, mod api.Module, ptr uint32) any {
const handleOffset = 4
handle := util.ReadUint32(mod, ptr-handleOffset)
return util.GetHandle(ctx, handle)
}
func vtabDelHandle(ctx context.Context, mod api.Module, ptr uint32) error {
const handleOffset = 4
handle := util.ReadUint32(mod, ptr-handleOffset)
return util.DelHandle(ctx, handle)
}
func vtabPutHandle(ctx context.Context, mod api.Module, pptr uint32, val any) {
const handleOffset = 4
handle := util.AddHandle(ctx, val)
ptr := util.ReadUint32(mod, pptr)
util.WriteUint32(mod, ptr-handleOffset, handle)
}