feat: ✨ Added Sqlite reader

vendor/modernc.org/sqlite/pre_update_hook.go

@@ -0,0 +1,227 @@
+package sqlite
+
+import (
+	"errors"
+	"fmt"
+	"sync"
+	"unsafe"
+
+	"modernc.org/libc"
+	"modernc.org/libc/sys/types"
+	sqlite3 "modernc.org/sqlite/lib"
+)
+
+var (
+	xPreUpdateHandlers = struct {
+		mu sync.RWMutex
+		m  map[uintptr]func(SQLitePreUpdateData)
+	}{
+		m: make(map[uintptr]func(SQLitePreUpdateData)),
+	}
+	xCommitHandlers = struct {
+		mu sync.RWMutex
+		m  map[uintptr]CommitHookFn
+	}{
+		m: make(map[uintptr]CommitHookFn),
+	}
+	xRollbackHandlers = struct {
+		mu sync.RWMutex
+		m  map[uintptr]RollbackHookFn
+	}{
+		m: make(map[uintptr]RollbackHookFn),
+	}
+)
+
+type PreUpdateHookFn func(SQLitePreUpdateData)
+
+func (c *conn) RegisterPreUpdateHook(callback PreUpdateHookFn) {
+
+	if callback == nil {
+		xPreUpdateHandlers.mu.Lock()
+		delete(xPreUpdateHandlers.m, c.db)
+		xPreUpdateHandlers.mu.Unlock()
+		sqlite3.Xsqlite3_preupdate_hook(c.tls, c.db, uintptr(unsafe.Pointer(nil)), uintptr(unsafe.Pointer(nil)))
+		return
+	}
+	xPreUpdateHandlers.mu.Lock()
+	xPreUpdateHandlers.m[c.db] = callback
+	xPreUpdateHandlers.mu.Unlock()
+
+	sqlite3.Xsqlite3_preupdate_hook(c.tls, c.db, cFuncPointer(preUpdateHookTrampoline), c.db)
+}
+
+type CommitHookFn func() int32
+
+func (c *conn) RegisterCommitHook(callback CommitHookFn) {
+	if callback == nil {
+		xCommitHandlers.mu.Lock()
+		delete(xCommitHandlers.m, c.db)
+		xCommitHandlers.mu.Unlock()
+		sqlite3.Xsqlite3_commit_hook(c.tls, c.db, uintptr(unsafe.Pointer(nil)), uintptr(unsafe.Pointer(nil)))
+		return
+	}
+	xCommitHandlers.mu.Lock()
+	xCommitHandlers.m[c.db] = callback
+	xCommitHandlers.mu.Unlock()
+	sqlite3.Xsqlite3_commit_hook(c.tls, c.db, cFuncPointer(commitHookTrampoline), c.db)
+}
+
+type RollbackHookFn func()
+
+func (c *conn) RegisterRollbackHook(callback RollbackHookFn) {
+	if callback == nil {
+		xRollbackHandlers.mu.Lock()
+		delete(xRollbackHandlers.m, c.db)
+		xRollbackHandlers.mu.Unlock()
+		sqlite3.Xsqlite3_rollback_hook(c.tls, c.db, uintptr(unsafe.Pointer(nil)), uintptr(unsafe.Pointer(nil)))
+		return
+	}
+	xRollbackHandlers.mu.Lock()
+	xRollbackHandlers.m[c.db] = callback
+	xRollbackHandlers.mu.Unlock()
+	sqlite3.Xsqlite3_rollback_hook(c.tls, c.db, cFuncPointer(rollbackHookTrampoline), c.db)
+}
+
+type SQLitePreUpdateData struct {
+	tls          *libc.TLS
+	pCsr         uintptr
+	Op           int32
+	DatabaseName string
+	TableName    string
+	OldRowID     int64
+	NewRowID     int64
+}
+
+// Depth returns the source path of the write, see sqlite3_preupdate_depth()
+func (d *SQLitePreUpdateData) Depth() int {
+	return int(sqlite3.Xsqlite3_preupdate_depth(d.tls, d.pCsr))
+}
+
+// Count returns the number of columns in the row
+func (d *SQLitePreUpdateData) Count() int {
+	return int(sqlite3.Xsqlite3_preupdate_count(d.tls, d.pCsr))
+}
+
+func (d *SQLitePreUpdateData) row(dest []any, new bool) error {
+	count := d.Count()
+	ppValue, err := mallocValue(d.tls)
+	if err != nil {
+		return err
+	}
+	defer libc.Xfree(d.tls, ppValue)
+
+	for i := 0; i < count && i < len(dest); i++ {
+		val, err := d.value(ppValue, i, new)
+		if err != nil {
+			return err
+		}
+		err = convertAssign(&dest[i], val)
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// Old populates dest with the row data to be replaced. This works similar to
+// database/sql's Rows.Scan()
+func (d *SQLitePreUpdateData) Old(dest ...any) error {
+	if d.Op == sqlite3.SQLITE_INSERT {
+		return errors.New("there is no old row for INSERT operations")
+	}
+	return d.row(dest, false)
+}
+
+// New populates dest with the replacement row data. This works similar to
+// database/sql's Rows.Scan()
+func (d *SQLitePreUpdateData) New(dest ...any) error {
+	if d.Op == sqlite3.SQLITE_DELETE {
+		return errors.New("there is no new row for DELETE operations")
+	}
+	return d.row(dest, true)
+}
+
+const ptrValSize = types.Size_t(unsafe.Sizeof(&sqlite3.Sqlite3_value{}))
+
+func mallocValue(tls *libc.TLS) (uintptr, error) {
+	p := libc.Xmalloc(tls, ptrValSize)
+	if p == 0 {
+		return 0, fmt.Errorf("out of memory")
+	}
+	return p, nil
+}
+
+func (d *SQLitePreUpdateData) value(ppValue uintptr, i int, new bool) (any, error) {
+	var src any
+	if new {
+		sqlite3.Xsqlite3_preupdate_new(d.tls, d.pCsr, int32(i), ppValue)
+	} else {
+		sqlite3.Xsqlite3_preupdate_old(d.tls, d.pCsr, int32(i), ppValue)
+	}
+	ptrValue := *(*uintptr)(unsafe.Pointer(ppValue))
+	switch sqlite3.Xsqlite3_value_type(d.tls, ptrValue) {
+	case sqlite3.SQLITE_INTEGER:
+		src = int64(sqlite3.Xsqlite3_value_int64(d.tls, ptrValue))
+	case sqlite3.SQLITE_FLOAT:
+		src = float64(sqlite3.Xsqlite3_value_double(d.tls, ptrValue))
+	case sqlite3.SQLITE_BLOB:
+		size := sqlite3.Xsqlite3_value_bytes(d.tls, ptrValue)
+		blobPtr := sqlite3.Xsqlite3_value_blob(d.tls, ptrValue)
+
+		var v []byte
+		if size != 0 {
+			v = make([]byte, size)
+			copy(v, (*libc.RawMem)(unsafe.Pointer(blobPtr))[:size:size])
+		}
+		src = v
+	case sqlite3.SQLITE_TEXT:
+		src = libc.GoString(sqlite3.Xsqlite3_value_text(d.tls, ptrValue))
+	case sqlite3.SQLITE_NULL:
+		src = nil
+	}
+	return src, nil
+}
+
+func preUpdateHookTrampoline(tls *libc.TLS, handle uintptr, pCsr uintptr, op int32, zDb uintptr, pTab uintptr, iKey1 int64, iReg int32, iBlobWrite int32) {
+	xPreUpdateHandlers.mu.RLock()
+	xPreUpdateHandler := xPreUpdateHandlers.m[handle]
+	xPreUpdateHandlers.mu.RUnlock()
+
+	if xPreUpdateHandler == nil {
+		return
+	}
+	data := SQLitePreUpdateData{
+		tls:          tls,
+		pCsr:         pCsr,
+		Op:           op,
+		DatabaseName: libc.GoString(zDb),
+		TableName:    libc.GoString(pTab),
+		OldRowID:     iKey1,
+		NewRowID:     int64(iReg),
+	}
+	xPreUpdateHandler(data)
+}
+
+func commitHookTrampoline(tls *libc.TLS, handle uintptr, pCsr uintptr) int32 {
+	xCommitHandlers.mu.RLock()
+	xCommitHandler := xCommitHandlers.m[handle]
+	xCommitHandlers.mu.RUnlock()
+
+	if xCommitHandler == nil {
+		return 0
+	}
+
+	return xCommitHandler()
+}
+
+func rollbackHookTrampoline(tls *libc.TLS, handle uintptr, pCsr uintptr) {
+	xRollbackHandlers.mu.RLock()
+	xRollbackHandler := xRollbackHandlers.m[handle]
+	xRollbackHandlers.mu.RUnlock()
+
+	if xRollbackHandler == nil {
+		return
+	}
+
+	xRollbackHandler()
+}