From 1fd986cc81137f408dd90bb52224453fb75060e6 Mon Sep 17 00:00:00 2001
From: Philip O'Toole <philip.otoole@yahoo.com>
Date: Tue, 11 Jun 2024 23:12:28 -0400
Subject: [PATCH] Support disabling checkpoint-on-close

Because Go doesn't support calling varadic C functions, this required a
wrapper.
---
 sqlite3.go      | 16 +++++++++
 sqlite3_test.go | 87 +++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 103 insertions(+)

diff --git a/sqlite3.go b/sqlite3.go
index 4ff905b5..9a8a6788 100644
--- a/sqlite3.go
+++ b/sqlite3.go
@@ -84,6 +84,12 @@ _sqlite3_bind_blob(sqlite3_stmt *stmt, int n, void *p, int np) {
   return sqlite3_bind_blob(stmt, n, p, np, SQLITE_TRANSIENT);
 }
 
+static int
+_sqlite3_db_config_no_ckpt_on_close(sqlite3 *db) {
+	int v;
+    return sqlite3_db_config(db, SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE, 1, &v);
+}
+
 #include <stdio.h>
 #include <stdint.h>
 
@@ -1898,6 +1904,16 @@ func (c *SQLiteConn) SetFileControlInt(dbName string, op int, arg int) error {
 	return nil
 }
 
+// DBConfigNoCkptOnClose disables checkpointing on database close.
+// See http://sqlite.org/c3ref/db_config.html
+func (c *SQLiteConn) DBConfigNoCkptOnClose() error {
+	rv := C._sqlite3_db_config_no_ckpt_on_close(c.db)
+	if rv != C.SQLITE_OK {
+		return c.lastError()
+	}
+	return nil
+}
+
 // Close the statement.
 func (s *SQLiteStmt) Close() error {
 	s.mu.Lock()
diff --git a/sqlite3_test.go b/sqlite3_test.go
index 63c939d3..5e2c8ca9 100644
--- a/sqlite3_test.go
+++ b/sqlite3_test.go
@@ -10,6 +10,7 @@ package sqlite3
 
 import (
 	"bytes"
+	"context"
 	"database/sql"
 	"database/sql/driver"
 	"errors"
@@ -1864,6 +1865,92 @@ func TestSetFileControlInt(t *testing.T) {
 	})
 }
 
+func TestDBConfigNoCkptOnClose(t *testing.T) {
+	fname := TempFilename(t)
+	defer os.Remove(fname)
+	db, err := sql.Open("sqlite3", fname)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+
+	// Enable WAL mode.
+	if _, err := db.Exec(`PRAGMA journal_mode = wal`); err != nil {
+		t.Fatal(err)
+	}
+
+	// Write some data.
+	_, err = db.Exec("create table foo (department integer, profits integer)")
+	if err != nil {
+		t.Fatal("Failed to create table:", err)
+	}
+
+	// Confirm WAL file exists.
+	if _, err := os.Stat(fname + "-wal"); err != nil {
+		t.Fatal("Expected WAL file to exist", err)
+	}
+
+	// Close the database, and confirm WAL file is removed.
+	if err := db.Close(); err != nil {
+		t.Fatal("Failed to close database", err)
+	}
+	if _, err := os.Stat(fname + "-wal"); err == nil {
+		t.Fatal("Expected WAL file to be removed after close")
+	}
+
+	// Now do it again, but with the DBConfig option set.
+	db, err = sql.Open("sqlite3", fname)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+
+	// Insert a record, confirm a WAL file appears.
+	if _, err := db.Exec(`insert into foo values (1, 2)`); err != nil {
+		t.Fatal(err)
+	}
+	if _, err := os.Stat(fname + "-wal"); err != nil {
+		t.Fatal("Expected WAL file to exist", err)
+	}
+
+	// Disable checkpoint-on-close.
+	f := func(driverConn interface{}) error {
+		c := driverConn.(*SQLiteConn)
+		return c.DBConfigNoCkptOnClose()
+	}
+	conn, err := db.Conn(context.Background())
+	if err != nil {
+		t.Fatal(err)
+	}
+	if err := conn.Raw(f); err != nil {
+		t.Fatal(err)
+	}
+
+	// Read the SQLite file into a byte slice for comparison later.
+	bufPre, err := os.ReadFile(fname)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// Close the database, and confirm WAL file is still present.
+	if err := db.Close(); err != nil {
+		t.Fatal("Failed to close database", err)
+	}
+	if _, err := os.Stat(fname + "-wal"); err != nil {
+		t.Fatal("Expected WAL file to be present after close", err)
+	}
+
+	// Confirm the SQLite file is the same as before since no checkpoint
+	// was performed.
+	bufPost, err := os.ReadFile(fname)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !bytes.Equal(bufPre, bufPost) {
+		t.Fatal("Expected SQLite file to be unchanged after close")
+	}
+}
+
 func TestNonColumnString(t *testing.T) {
 	db, err := sql.Open("sqlite3", ":memory:")
 	if err != nil {