gotosocial/vendor/github.com/ncruces/go-sqlite3/func.go
2024-10-25 16:09:18 +00:00

231 lines
6.9 KiB
Go

package sqlite3
import (
"context"
"sync"
"github.com/tetratelabs/wazero/api"
"github.com/ncruces/go-sqlite3/internal/util"
)
// CollationNeeded registers a callback to be invoked
// whenever an unknown collation sequence is required.
//
// https://sqlite.org/c3ref/collation_needed.html
func (c *Conn) CollationNeeded(cb func(db *Conn, name string)) error {
var enable uint64
if cb != nil {
enable = 1
}
r := c.call("sqlite3_collation_needed_go", uint64(c.handle), enable)
if err := c.error(r); err != nil {
return err
}
c.collation = cb
return nil
}
// AnyCollationNeeded uses [Conn.CollationNeeded] to register
// a fake collating function for any unknown collating sequence.
// The fake collating function works like BINARY.
//
// This can be used to load schemas that contain
// one or more unknown collating sequences.
func (c Conn) AnyCollationNeeded() error {
r := c.call("sqlite3_anycollseq_init", uint64(c.handle), 0, 0)
if err := c.error(r); err != nil {
return err
}
c.collation = nil
return nil
}
// CreateCollation defines a new collating sequence.
//
// https://sqlite.org/c3ref/create_collation.html
func (c *Conn) CreateCollation(name string, fn func(a, b []byte) int) error {
var funcPtr uint32
defer c.arena.mark()()
namePtr := c.arena.string(name)
if fn != nil {
funcPtr = util.AddHandle(c.ctx, fn)
}
r := c.call("sqlite3_create_collation_go",
uint64(c.handle), uint64(namePtr), uint64(funcPtr))
return c.error(r)
}
// CreateFunction defines a new scalar SQL function.
//
// https://sqlite.org/c3ref/create_function.html
func (c *Conn) CreateFunction(name string, nArg int, flag FunctionFlag, fn ScalarFunction) error {
var funcPtr uint32
defer c.arena.mark()()
namePtr := c.arena.string(name)
if fn != nil {
funcPtr = util.AddHandle(c.ctx, fn)
}
r := c.call("sqlite3_create_function_go",
uint64(c.handle), uint64(namePtr), uint64(nArg),
uint64(flag), uint64(funcPtr))
return c.error(r)
}
// ScalarFunction is the type of a scalar SQL function.
// Implementations must not retain arg.
type ScalarFunction func(ctx Context, arg ...Value)
// CreateWindowFunction defines a new aggregate or aggregate window SQL function.
// If fn returns a [WindowFunction], then an aggregate window function is created.
// If fn returns an [io.Closer], it will be called to free resources.
//
// https://sqlite.org/c3ref/create_function.html
func (c *Conn) CreateWindowFunction(name string, nArg int, flag FunctionFlag, fn func() AggregateFunction) error {
var funcPtr uint32
defer c.arena.mark()()
namePtr := c.arena.string(name)
if fn != nil {
funcPtr = util.AddHandle(c.ctx, fn)
}
call := "sqlite3_create_aggregate_function_go"
if _, ok := fn().(WindowFunction); ok {
call = "sqlite3_create_window_function_go"
}
r := c.call(call,
uint64(c.handle), uint64(namePtr), uint64(nArg),
uint64(flag), uint64(funcPtr))
return c.error(r)
}
// AggregateFunction is the interface an aggregate function should implement.
//
// https://sqlite.org/appfunc.html
type AggregateFunction interface {
// Step is invoked to add a row to the current window.
// The function arguments, if any, corresponding to the row being added, are passed to Step.
// Implementations must not retain arg.
Step(ctx Context, arg ...Value)
// Value is invoked to return the current (or final) value of the aggregate.
Value(ctx Context)
}
// WindowFunction is the interface an aggregate window function should implement.
//
// https://sqlite.org/windowfunctions.html
type WindowFunction interface {
AggregateFunction
// Inverse is invoked to remove the oldest presently aggregated result of Step from the current window.
// The function arguments, if any, are those passed to Step for the row being removed.
// Implementations must not retain arg.
Inverse(ctx Context, arg ...Value)
}
// OverloadFunction overloads a function for a virtual table.
//
// https://sqlite.org/c3ref/overload_function.html
func (c *Conn) OverloadFunction(name string, nArg int) error {
defer c.arena.mark()()
namePtr := c.arena.string(name)
r := c.call("sqlite3_overload_function",
uint64(c.handle), uint64(namePtr), uint64(nArg))
return c.error(r)
}
func destroyCallback(ctx context.Context, mod api.Module, pApp uint32) {
util.DelHandle(ctx, pApp)
}
func collationCallback(ctx context.Context, mod api.Module, pArg, pDB, eTextRep, zName uint32) {
if c, ok := ctx.Value(connKey{}).(*Conn); ok && c.handle == pDB && c.collation != nil {
name := util.ReadString(mod, zName, _MAX_NAME)
c.collation(c, name)
}
}
func compareCallback(ctx context.Context, mod api.Module, pApp, nKey1, pKey1, nKey2, pKey2 uint32) uint32 {
fn := util.GetHandle(ctx, pApp).(func(a, b []byte) int)
return uint32(fn(util.View(mod, pKey1, uint64(nKey1)), util.View(mod, pKey2, uint64(nKey2))))
}
func funcCallback(ctx context.Context, mod api.Module, pCtx, pApp, nArg, pArg uint32) {
args := getFuncArgs()
defer putFuncArgs(args)
db := ctx.Value(connKey{}).(*Conn)
fn := util.GetHandle(db.ctx, pApp).(ScalarFunction)
callbackArgs(db, args[:nArg], pArg)
fn(Context{db, pCtx}, args[:nArg]...)
}
func stepCallback(ctx context.Context, mod api.Module, pCtx, pAgg, pApp, nArg, pArg uint32) {
args := getFuncArgs()
defer putFuncArgs(args)
db := ctx.Value(connKey{}).(*Conn)
callbackArgs(db, args[:nArg], pArg)
fn, _ := callbackAggregate(db, pAgg, pApp)
fn.Step(Context{db, pCtx}, args[:nArg]...)
}
func finalCallback(ctx context.Context, mod api.Module, pCtx, pAgg, pApp uint32) {
db := ctx.Value(connKey{}).(*Conn)
fn, handle := callbackAggregate(db, pAgg, pApp)
fn.Value(Context{db, pCtx})
util.DelHandle(ctx, handle)
}
func valueCallback(ctx context.Context, mod api.Module, pCtx, pAgg uint32) {
db := ctx.Value(connKey{}).(*Conn)
fn := util.GetHandle(db.ctx, pAgg).(AggregateFunction)
fn.Value(Context{db, pCtx})
}
func inverseCallback(ctx context.Context, mod api.Module, pCtx, pAgg, nArg, pArg uint32) {
args := getFuncArgs()
defer putFuncArgs(args)
db := ctx.Value(connKey{}).(*Conn)
callbackArgs(db, args[:nArg], pArg)
fn := util.GetHandle(db.ctx, pAgg).(WindowFunction)
fn.Inverse(Context{db, pCtx}, args[:nArg]...)
}
func callbackAggregate(db *Conn, pAgg, pApp uint32) (AggregateFunction, uint32) {
if pApp == 0 {
handle := util.ReadUint32(db.mod, pAgg)
return util.GetHandle(db.ctx, handle).(AggregateFunction), handle
}
// We need to create the aggregate.
fn := util.GetHandle(db.ctx, pApp).(func() AggregateFunction)()
if pAgg != 0 {
handle := util.AddHandle(db.ctx, fn)
util.WriteUint32(db.mod, pAgg, handle)
return fn, handle
}
return fn, 0
}
func callbackArgs(db *Conn, arg []Value, pArg uint32) {
for i := range arg {
arg[i] = Value{
c: db,
handle: util.ReadUint32(db.mod, pArg+ptrlen*uint32(i)),
}
}
}
var funcArgsPool sync.Pool
func putFuncArgs(p *[_MAX_FUNCTION_ARG]Value) {
funcArgsPool.Put(p)
}
func getFuncArgs() *[_MAX_FUNCTION_ARG]Value {
if p := funcArgsPool.Get(); p == nil {
return new([_MAX_FUNCTION_ARG]Value)
} else {
return p.(*[_MAX_FUNCTION_ARG]Value)
}
}