First version of implementation

Author: otoolep

sqlite3.go

@@ -27,6 +27,8 @@ package sqlite3
 #cgo CFLAGS: -DSQLITE_ENABLE_DBSTAT_VTAB
 #cgo CFLAGS: -DSQLITE_MEMDB_DEFAULT_MAXSIZE=2147483648
 #cgo CFLAGS: -DSQLITE_ENABLE_GEOPOLY=1
+#cgo CFLAGS: -DSQLITE_ENABLE_SESSION
+#cgo CFLAGS: -DSQLITE_ENABLE_PREUPDATE_HOOK
 #cgo CFLAGS: -Wno-deprecated-declarations
 #cgo openbsd CFLAGS: -I/usr/local/include
 #cgo openbsd LDFLAGS: -L/usr/local/lib

sqlite3_session.go

@@ -15,60 +15,153 @@ package sqlite3
 #include <sqlite3.h>
 #endif
 #include <stdlib.h>
+#include <stdint.h>
 */
 import "C"
+import (
+	"fmt"
+	"unsafe"
+)
+
+type Session struct {
+	session *C.sqlite3_session
+}
+
+type Changeset struct {
+	changeset *C.sqlite3_changeset_iter
+}
 
 // CreateSession creates a new session object.
-func (c *SQLiteConn) CreateSession() error {
-	return nil
+func (c *SQLiteConn) CreateSession(dbName string) (*Session, error) {
+	cDbName := C.CString(dbName)
+	defer C.free(unsafe.Pointer(cDbName))
+
+	var session *C.sqlite3_session
+	rc := C.sqlite3session_create(c.db, cDbName, &session)
+	if rc != C.SQLITE_OK {
+		return nil, fmt.Errorf("sqlite3session_create: %s", C.GoString(C.sqlite3_errstr(rc)))
+	}
+	return &Session{session: session}, nil
 }
 
-// AttachSession attaches a session object to a set of tables.
-func (c *SQLiteConn) AttachSession() error {
+// AttachSession attaches a session object to a table or all tables.
+func (s *Session) AttachSession(tableName string) error {
+	var cTableName *C.char
+	if tableName != "" {
+		cTableName = C.CString(tableName)
+		defer C.free(unsafe.Pointer(cTableName))
+	}
+
+	rc := C.sqlite3session_attach(s.session, cTableName)
+	if rc != C.SQLITE_OK {
+		return fmt.Errorf("sqlite3session_attach: %s", C.GoString(C.sqlite3_errstr(rc)))
+	}
 	return nil
 }
 
-// DetachSession deletes a session object.
-func (c *SQLiteConn) DeleteSession() error {
+// Delete deletes a session object.
+func (s *Session) DeleteSession() error {
+	if s.session != nil {
+		// Call sqlite3session_delete to free the session object
+		C.sqlite3session_delete(s.session)
+		s.session = nil // Set session to nil to avoid double deletion
+	}
 	return nil
 }
 
-// SessionChangeset generates a changeset from a session object.
-func (c *SQLiteConn) Changeset() error {
-	return nil
+type ChangesetIter struct {
+	iter *C.sqlite3_changeset_iter
 }
 
-// ChangesetStart is called to create and initialize an iterator
-// to iterate through the contents of a changeset. Initially, the
-// iterator points to no element at all
-func (c *SQLiteConn) ChangesetStart() error {
-	return nil
+// Changeset generates a changeset from a session object.
+func (s *Session) Changeset() ([]byte, error) {
+	var nChangeset C.int
+	var pChangeset unsafe.Pointer
+
+	// Call sqlite3session_changeset
+	rc := C.sqlite3session_changeset(s.session, &nChangeset, &pChangeset)
+	if rc != C.SQLITE_OK {
+		return nil, fmt.Errorf("sqlite3session_changeset: %s", C.GoString(C.sqlite3_errstr(rc)))
+	}
+	defer C.sqlite3_free(pChangeset) // Free the changeset buffer after use
+
+	// Convert the C buffer to a Go byte slice
+	changeset := C.GoBytes(pChangeset, nChangeset)
+	return changeset, nil
 }
 
-// ChangesetNext moves a Changeset iterator to the next change in the
-// changeset.
-func (c *SQLiteConn) ChangesetNext() error {
-	return nil
+// ChangesetStart creates and initializes a changeset iterator.
+func ChangesetStart(changeset []byte) (*ChangesetIter, error) {
+	var iter *C.sqlite3_changeset_iter
+
+	// Call sqlite3changeset_start
+	rc := C.sqlite3changeset_start(&iter, C.int(len(changeset)), unsafe.Pointer(&changeset[0]))
+	if rc != C.SQLITE_OK {
+		return nil, fmt.Errorf("sqlite3changeset_start: %s", C.GoString(C.sqlite3_errstr(rc)))
+	}
+
+	return &ChangesetIter{iter: iter}, nil
 }
 
-// ChangesetOp retuns the type of change (INSERT, UPDATE or DELETE)
-// that the iterator points to
-func (c *SQLiteConn) ChangesetOp() error {
-	return nil
+// ChangesetNext moves the changeset iterator to the next change.
+func (ci *ChangesetIter) ChangesetNext() (bool, error) {
+	rc := C.sqlite3changeset_next(ci.iter)
+	if rc == C.SQLITE_DONE {
+		return false, nil // No more changes
+	}
+	if rc != C.SQLITE_OK {
+		return false, fmt.Errorf("sqlite3changeset_next: %s", C.GoString(C.sqlite3_errstr(rc)))
+	}
+	return true, nil
 }
 
-// ChangesetOld may be used to obtain the old.* values within the change payload.
-func (c *SQLiteConn) ChangesetOld() error {
-	return nil
+// ChangesetOp returns the type of change (INSERT, UPDATE, or DELETE) that the iterator points to.
+func (ci *ChangesetIter) ChangesetOp() (string, int, int, bool, error) {
+	var tableName *C.char
+	var nCol C.int
+	var op C.int
+	var indirect C.int
+
+	rc := C.sqlite3changeset_op(ci.iter, &tableName, &nCol, &op, &indirect)
+	if rc != C.SQLITE_OK {
+		return "", 0, 0, false, fmt.Errorf("sqlite3changeset_op: %s", C.GoString(C.sqlite3_errstr(rc)))
+	}
+
+	return C.GoString(tableName), int(nCol), int(op), indirect != 0, nil
 }
 
-// ChangesetNew may be used to obtain the new.* values within the change payload.
-func (c *SQLiteConn) ChangesetNew() error {
-	return nil
+// ChangesetOld retrieves the old value for the specified column in the change payload.
+func (ci *ChangesetIter) ChangesetOld(column int) (*C.sqlite3_value, error) {
+	var value *C.sqlite3_value
+
+	rc := C.sqlite3changeset_old(ci.iter, C.int(column), &value)
+	if rc != C.SQLITE_OK {
+		return nil, fmt.Errorf("sqlite3changeset_old: %s", C.GoString(C.sqlite3_errstr(rc)))
+	}
+
+	return value, nil
 }
 
-// ChangesetFinalize is called to delete a changeste iterator.
-func (c *SQLiteConn) ChangesetFinalize() error {
-	return nil
+// ChangesetNew retrieves the new value for the specified column in the change payload.
+func (ci *ChangesetIter) ChangesetNew(column int) (*C.sqlite3_value, error) {
+	var value *C.sqlite3_value
+
+	rc := C.sqlite3changeset_new(ci.iter, C.int(column), &value)
+	if rc != C.SQLITE_OK {
+		return nil, fmt.Errorf("sqlite3changeset_new: %s", C.GoString(C.sqlite3_errstr(rc)))
+	}
+
+	return value, nil
 }
 
+// ChangesetFinalize deletes a changeset iterator.
+func (ci *ChangesetIter) ChangesetFinalize() error {
+	if ci.iter != nil {
+		rc := C.sqlite3changeset_finalize(ci.iter)
+		ci.iter = nil // Prevent double finalization
+		if rc != C.SQLITE_OK {
+			return fmt.Errorf("sqlite3changeset_finalize: %s", C.GoString(C.sqlite3_errstr(rc)))
+		}
+	}
+	return nil
+}