Coverage, docs.

README.md

@@ -10,7 +10,7 @@ as well as direct access to most of the [C SQLite API](https://sqlite.org/cintro
 
 It wraps a [Wasm](https://webassembly.org/) [build](embed/) of SQLite,
 and uses [wazero](https://wazero.io/) as the runtime.\
-Go, wazero and [`x/sys`](https://pkg.go.dev/golang.org/x/sys) are the _only_ runtime dependencies [^1].
+Go, wazero and [`x/sys`](https://pkg.go.dev/golang.org/x/sys) are the _only_ runtime dependencies.
 
 ### Getting started
 
@@ -49,6 +49,8 @@ db.QueryRow(`SELECT sqlite_version()`).Scan(&version)
   simplifies [incremental BLOB I/O](https://sqlite.org/c3ref/blob_open.html).
 - [`github.com/ncruces/go-sqlite3/ext/bloom`](https://pkg.go.dev/github.com/ncruces/go-sqlite3/ext/bloom)
   provides a [Bloom filter](https://github.com/nalgeon/sqlean/issues/27#issuecomment-1002267134) virtual table.
+- [`github.com/ncruces/go-sqlite3/ext/closure`](https://pkg.go.dev/github.com/ncruces/go-sqlite3/ext/closure)
+  provides a transitive closure virtual table.
 - [`github.com/ncruces/go-sqlite3/ext/csv`](https://pkg.go.dev/github.com/ncruces/go-sqlite3/ext/csv)
   reads [comma-separated values](https://sqlite.org/csv.html).
 - [`github.com/ncruces/go-sqlite3/ext/fileio`](https://pkg.go.dev/github.com/ncruces/go-sqlite3/ext/fileio)
@@ -128,7 +130,4 @@ The Wasm and VFS layers are also tested by running SQLite's
 - [`modernc.org/sqlite`](https://pkg.go.dev/modernc.org/sqlite)
 - [`crawshaw.io/sqlite`](https://pkg.go.dev/crawshaw.io/sqlite)
 - [`github.com/mattn/go-sqlite3`](https://pkg.go.dev/github.com/mattn/go-sqlite3)
-- [`github.com/zombiezen/go-sqlite`](https://pkg.go.dev/github.com/zombiezen/go-sqlite)
-
-[^1]: anything else you find in `go.mod` is either a test dependency,
-      or needed by one of the extensions.
+- [`github.com/zombiezen/go-sqlite`](https://pkg.go.dev/github.com/zombiezen/go-sqlite)

ext/bloom/bloom.go

@@ -272,10 +272,6 @@ type cursor struct {
 }
 
 func (c *cursor) Filter(idxNum int, idxStr string, arg ...sqlite3.Value) error {
-	if len(arg) != 1 {
-		return nil
-	}
-
 	c.eof = false
 	c.arg = &arg[0]
 	blob := arg[0].RawBlob()

ext/closure/closure.go

@@ -1,6 +1,6 @@
 // Package closure provides a transitive closure virtual table.
 //
-// The "transitive_closure" virtual table finds the transitive closure of
+// The transitive_closure virtual table finds the transitive closure of
 // a parent/child relationship in a real table.
 //
 // https://sqlite.org/src/doc/tip/ext/misc/closure.c
@@ -24,6 +24,9 @@ const (
 	_COL_PARENTCOLUMN = 5
 )
 
+// Register registers the transitive_closure virtual table:
+//
+//	CREATE VIRTUAL TABLE temp.closure USING transitive_closure;
 func Register(db *sqlite3.Conn) error {
 	return sqlite3.CreateModule(db, "transitive_closure", nil,
 		func(db *sqlite3.Conn, _, _, _ string, arg ...string) (*closure, error) {
@@ -76,9 +79,9 @@ type closure struct {
 func (c *closure) Destroy() error { return nil }
 
 func (c *closure) BestIndex(idx *sqlite3.IndexInfo) error {
-	posi := 1
 	plan := 0
-	cost := 10000000.0
+	posi := 1
+	cost := 1e7
 
 	for i, cst := range idx.Constraint {
 		if !cst.Usable {
@@ -140,17 +143,11 @@ func (c *closure) BestIndex(idx *sqlite3.IndexInfo) error {
 		}
 	}
 
-	if c.table == "" && plan&0xf00 == 0 ||
+	if plan&1 == 0 ||
+		c.table == "" && plan&0xf00 == 0 ||
 		c.column == "" && plan&0xf000 == 0 ||
 		c.parent == "" && plan&0xf0000 == 0 {
-		plan = 0
-	}
-	if plan&1 == 0 {
-		plan = 0
-		cost *= 1e30
-		for i := range idx.Constraint {
-			idx.ConstraintUsage[i].ArgvIndex = 0
-		}
+		return sqlite3.CONSTRAINT
 	}
 
 	idx.EstimatedCost = cost
@@ -173,10 +170,6 @@ type node struct {
 }
 
 func (c *cursor) Filter(idxNum int, idxStr string, arg ...sqlite3.Value) error {
-	if idxNum&1 == 0 {
-		return nil
-	}
-
 	root := arg[0].Int64()
 	maxDepth := math.MaxInt
 	if idxNum&0xf0 != 0 {

ext/closure/closure_test.go

@@ -24,6 +24,8 @@ func Example() {
 	}
 	defer db.Close()
 
+	closure.Register(db)
+
 	err = db.Exec(`
 		CREATE TABLE employees (
 			id INTEGER PRIMARY KEY,
@@ -150,3 +152,33 @@ func TestRegister(t *testing.T) {
 		t.Fatal(err)
 	}
 }
+
+func Test_errors(t *testing.T) {
+	t.Parallel()
+
+	db, err := sqlite3.Open(":memory:")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+
+	err = db.Exec(`CREATE VIRTUAL TABLE hierarchy USING transitive_closure(table='employees')`)
+	if err == nil {
+		t.Error("want error")
+	}
+
+	err = db.Exec(`CREATE VIRTUAL TABLE hierarchy USING transitive_closure(tablename='employees', tablename="employees")`)
+	if err == nil {
+		t.Error("want error")
+	}
+
+	err = db.Exec("CREATE VIRTUAL TABLE hierarchy USING transitive_closure(tablename=`employees`)")
+	if err != nil {
+		t.Error(err)
+	}
+
+	err = db.Exec(`SELECT * FROM hierarchy`)
+	if err == nil {
+		t.Error("want error")
+	}
+}

ext/fileio/fsdir.go

@@ -10,13 +10,22 @@ import (
 	"github.com/ncruces/go-sqlite3"
 )
 
+const (
+	_COL_NAME = 0
+	_COL_MODE = 1
+	_COL_TIME = 2
+	_COL_DATA = 3
+	_COL_ROOT = 4
+	_COL_BASE = 5
+)
+
 type fsdir struct{ fsys fs.FS }
 
 func (d fsdir) BestIndex(idx *sqlite3.IndexInfo) error {
 	var root, base bool
 	for i, cst := range idx.Constraint {
 		switch cst.Column {
-		case 4: // root
+		case _COL_ROOT:
 			if !cst.Usable || cst.Op != sqlite3.INDEX_CONSTRAINT_EQ {
 				return sqlite3.CONSTRAINT
 			}
@@ -25,7 +34,7 @@ func (d fsdir) BestIndex(idx *sqlite3.IndexInfo) error {
 				ArgvIndex: 1,
 			}
 			root = true
-		case 5: // base
+		case _COL_BASE:
 			if !cst.Usable || cst.Op != sqlite3.INDEX_CONSTRAINT_EQ {
 				return sqlite3.CONSTRAINT
 			}
@@ -116,25 +125,25 @@ func (c *cursor) RowID() (int64, error) {
 
 func (c *cursor) Column(ctx sqlite3.Context, n int) error {
 	switch n {
-	case 0: // name
+	case _COL_NAME:
 		name := strings.TrimPrefix(c.curr.path, c.base)
 		ctx.ResultText(name)
 
-	case 1: // mode
+	case _COL_MODE:
 		i, err := c.curr.Info()
 		if err != nil {
 			return err
 		}
 		ctx.ResultInt64(int64(i.Mode()))
 
-	case 2: // mtime
+	case _COL_TIME:
 		i, err := c.curr.Info()
 		if err != nil {
 			return err
 		}
 		ctx.ResultTime(i.ModTime(), sqlite3.TimeFormatUnixFrac)
 
-	case 3: // data
+	case _COL_DATA:
 		switch typ := c.curr.Type(); {
 		case typ.IsRegular():
 			var data []byte

util/vtabutil/arg.go

@@ -26,6 +26,8 @@ func Unquote(val string) string {
 		return val
 	case '"':
 		old, new = `""`, `"`
+	case '`':
+		old, new = "``", "`"
 	case '\'':
 		old, new = `''`, `'`
 	}