add pg_range support (#15)

* add pg_range support

* fix correct table name

2 files changed, 116 insertions, 0 deletions

diff --git a/pg_range.go b/pg_range.go
new file mode 100644
index 0000000..bfb71fe
--- /dev/null
+++ b/pg_range.go
@@ -0,0 +1,110 @@
+package postlite
+
+import (
+	"fmt"
+
+	"github.com/mattn/go-sqlite3"
+)
+
+type pgRangeModule struct{}
+
+func (m *pgRangeModule) Create(c *sqlite3.SQLiteConn, args []string) (sqlite3.VTab, error) {
+	err := c.DeclareVTab(fmt.Sprintf(`
+		CREATE TABLE %s (
+			rngtypid 	INTEGER,
+			rngsubtype	INTEGER,
+			rngmultitypid	INTEGER,
+			rngcollation	INTEGER,
+			rngsubopc	INTEGER,
+			rngcanonical	TEXT,
+			rngsubdiff	TEXT
+		)`, args[0]))
+	if err != nil {
+		return nil, err
+	}
+	return &pgNamespaceTable{}, nil
+}
+
+func (m *pgRangeModule) Connect(c *sqlite3.SQLiteConn, args []string) (sqlite3.VTab, error) {
+	return m.Create(c, args)
+}
+
+func (m *pgRangeModule) DestroyModule() {}
+
+type pgRangeTable struct{}
+
+func (t *pgRangeTable) Open() (sqlite3.VTabCursor, error) {
+	return &pgTypeCursor{}, nil
+}
+
+func (t *pgRangeTable) BestIndex(cst []sqlite3.InfoConstraint, ob []sqlite3.InfoOrderBy) (*sqlite3.IndexResult, error) {
+	return &sqlite3.IndexResult{Used: make([]bool, len(cst))}, nil
+}
+
+func (t *pgRangeTable) Disconnect() error { return nil }
+func (t *pgRangeTable) Destroy() error    { return nil }
+
+type pgRangeCursor struct {
+	index int
+}
+
+func (c *pgRangeCursor) Column(sctx *sqlite3.SQLiteContext, col int) error {
+	switch col {
+	case 0:
+		sctx.ResultInt(pgRanges[c.index].rngtypid)
+	case 1:
+		sctx.ResultInt(pgRanges[c.index].rngsubtype)
+	case 2:
+		sctx.ResultInt(pgRanges[c.index].rngmultitypid)
+	case 3:
+		sctx.ResultInt(pgRanges[c.index].rngcollation)
+	case 4:
+		sctx.ResultInt(pgRanges[c.index].rngsubopc)
+	case 5:
+		sctx.ResultText(pgRanges[c.index].rngcanonical)
+	case 6:
+		sctx.ResultText(pgRanges[c.index].rngsubdiff)
+	}
+	return nil
+}
+
+func (c *pgRangeCursor) Filter(idxNum int, idxStr string, vals []interface{}) error {
+	c.index = 0
+	return nil
+}
+
+func (c *pgRangeCursor) Next() error {
+	c.index++
+	return nil
+}
+
+func (c *pgRangeCursor) EOF() bool {
+	return c.index >= len(pgTypes)
+}
+
+func (c *pgRangeCursor) Rowid() (int64, error) {
+	return int64(c.index), nil
+}
+
+func (c *pgRangeCursor) Close() error {
+	return nil
+}
+
+type pgRange struct {
+	rngtypid      int
+	rngsubtype    int
+	rngmultitypid int
+	rngcollation  int
+	rngsubopc     int
+	rngcanonical  string
+	rngsubdiff    string
+}
+
+var pgRanges = []pgRange{
+	{3904, 23, 4451, 0, 1978, "", ""},
+	{3906, 1700, 4532, 0, 3125, "", ""},
+	{3908, 1114, 4533, 0, 3128, "", ""},
+	{3910, 1184, 4534, 0, 3127, "", ""},
+	{3912, 1082, 4535, 0, 3122, "", ""},
+	{3926, 20, 4536, 0, 3124, "", ""},
+}
diff --git a/server.go b/server.go
index c49a722..190e0a8 100644
--- a/server.go
+++ b/server.go
@@ -70,6 +70,9 @@ func init() {
 			if err := conn.CreateModule("pg_class_module", &pgClassModule{}); err != nil {
 				return fmt.Errorf("cannot register pg_class module")
 			}
+			if err := conn.CreateModule("pg_range_module", &pgRangeModule{}); err != nil {
+				return fmt.Errorf("cannot register pg_range module")
+			}
 			return nil
 		},
 	})
@@ -303,6 +306,9 @@ func (s *Server) handleStartupMessage(ctx context.Context, c *Conn, msg *pgproto
 	if _, err := c.db.Exec("CREATE VIRTUAL TABLE IF NOT EXISTS pg_catalog.pg_class USING pg_class_module (oid, relname, relnamespace, reltype, reloftype, relowner, relam, relfilenode, reltablespace, relpages, reltuples, relallvisible, reltoastrelid, relhasindex, relisshared, relpersistence, relkind, relnatts, relchecks, relhasrules, relhastriggers, relhassubclass, relrowsecurity, relforcerowsecurity, relispopulated, relreplident, relispartition, relrewrite, relfrozenxid, relminmxid, relacl, reloptions, relpartbound)"); err != nil {
 		return fmt.Errorf("create pg_class: %w", err)
 	}
+	if _, err := c.db.Exec("CREATE VIRTUAL TABLE IF NOT EXISTS pg_catalog.pg_range USING pg_range_module (rngtypid, rngsubtype, rngmultitypid, rngcollation, rngsubopc, rngcanonical, rngsubdiff)"); err != nil {
+		return fmt.Errorf("create pg_range: %w", err)
+	}
 
 	return writeMessages(c,
 		&pgproto3.AuthenticationOk{},