sqlite: initial support

go.mod

@@ -3,6 +3,7 @@ module yvbolt
 go 1.19
 
 require (
+	github.com/mattn/go-sqlite3 v1.14.22 // indirect
 	github.com/ying32/govcl v2.2.3+incompatible // indirect
 	go.etcd.io/bbolt v1.3.10 // indirect
 	golang.org/x/sys v0.4.0 // indirect

go.sum

@@ -1,3 +1,5 @@
+github.com/mattn/go-sqlite3 v1.14.22 h1:2gZY6PC6kBnID23Tichd1K+Z0oS6nE/XwU+Vz/5o4kU=
+github.com/mattn/go-sqlite3 v1.14.22/go.mod h1:Uh1q+B4BYcTPb+yiD3kU8Ct7aC0hY9fxUwlHK0RXw+Y=
 github.com/ying32/govcl v2.2.3+incompatible h1:Iyfcl26yNE1USm+3uG+btQyhkoFIV18+VITrUdHu8Lw=
 github.com/ying32/govcl v2.2.3+incompatible/go.mod h1:yZVtbJ9Md1nAVxtHKIriKZn4K6TQYqI1en3sN/m9FJ8=
 go.etcd.io/bbolt v1.3.10 h1:+BqfJTcCzTItrop8mq/lbzL8wSGtj94UO/3U31shqG0=

main.go

@@ -10,7 +10,6 @@ import (
 	_ "github.com/ying32/govcl/pkgs/winappres" // Extra _syso files for Windows
 	"github.com/ying32/govcl/vcl"
 	"github.com/ying32/govcl/vcl/types"
-
 )
 
 type TMainForm struct {
@@ -47,6 +46,11 @@ func (f *TMainForm) OnFormCreate(sender vcl.IObject) {
 	mnuFileOpen.SetOnClick(f.OnMnuFileOpenClick)
 	mnuFile.Add(mnuFileOpen)
 
+	mnuFileSqliteMemory := vcl.NewMenuItem(mnuFile)
+	mnuFileSqliteMemory.SetCaption("New SQLite in-memory database")
+	mnuFileSqliteMemory.SetOnClick(f.OnmnuFileSqliteMemoryClick)
+	mnuFile.Add(mnuFileSqliteMemory)
+
 	mnuSep := vcl.NewMenuItem(mnuFile)
 	mnuSep.SetCaption("-") // Creates separator
 	mnuFile.Add(mnuSep)
@@ -123,6 +127,10 @@ func (f *TMainForm) OnMnuFileExitClick(sender vcl.IObject) {
 	os.Exit(0)
 }
 
+func (f *TMainForm) OnmnuFileSqliteMemoryClick(sender vcl.IObject) {
+	f.SQLite_AddFromFile(`:memory:`)
+}
+
 func (f *TMainForm) OnNavChange(sender vcl.IObject, node *vcl.TTreeNode) {
 
 	if node.Data() == nil {

sqlite.go

@@ -0,0 +1,132 @@
+package main
+
+import (
+	"database/sql"
+	"fmt"
+	"path/filepath"
+	"unsafe"
+
+	_ "github.com/mattn/go-sqlite3"
+	"github.com/ying32/govcl/vcl"
+)
+
+const (
+	sqliteTablesCaption = "Tables"
+)
+
+type sqliteLoadedDatabase struct {
+	displayName string
+	path        string
+	db          *sql.DB
+	nav         *vcl.TTreeNode
+
+	arena []*navData // keepalive
+}
+
+func (ld *sqliteLoadedDatabase) DisplayName() string {
+	return ld.displayName
+}
+
+func (ld *sqliteLoadedDatabase) RootElement() *vcl.TTreeNode {
+	return ld.nav
+}
+
+func (ld *sqliteLoadedDatabase) Keepalive(ndata *navData) {
+	ld.arena = append(ld.arena, ndata)
+}
+
+func (ld *sqliteLoadedDatabase) RenderForNav(f *TMainForm, ndata *navData) {
+
+	if len(ndata.bucketPath) == 0 {
+		// Top-level
+		f.propertiesBox.SetText("Please select...")
+		f.contentBox.SetEnabled(false)
+		f.contentBox.Clear()
+
+	} else if len(ndata.bucketPath) == 1 {
+		// Category (tables, ...)
+		f.propertiesBox.SetText("Please select...")
+		f.contentBox.SetEnabled(false)
+		f.contentBox.Clear()
+
+	} else if ndata.bucketPath[0] == sqliteTablesCaption {
+		// Render for specific table
+		f.propertiesBox.SetText(fmt.Sprintf("Selected table %q", ndata.bucketPath[1]))
+		// Load schema
+		// Select * with small limit
+		f.contentBox.SetEnabled(false)
+		f.contentBox.Clear()
+
+	} else {
+		// ??? unknown
+
+	}
+
+}
+
+func (ld *sqliteLoadedDatabase) NavChildren(ndata *navData) ([]string, error) {
+
+	if len(ndata.bucketPath) == 0 {
+		// The top-level children are always:
+		return []string{sqliteTablesCaption}, nil
+	}
+
+	if ndata.bucketPath[0] == sqliteTablesCaption {
+		rr, err := ld.db.Query(`SELECT name FROM sqlite_master WHERE type='table' ORDER BY name ASC;`)
+		if err != nil {
+			return nil, err
+		}
+		defer rr.Close()
+
+		var gather []string
+		for rr.Next() {
+			var tableName string
+			err = rr.Scan(&tableName)
+			if err != nil {
+				return nil, err
+			}
+
+			gather = append(gather, tableName)
+		}
+		if rr.Err() != nil {
+			return nil, rr.Err()
+		}
+
+		return gather, nil
+	}
+
+	return nil, fmt.Errorf("unknown nav path %#v", ndata.bucketPath)
+}
+
+var _ loadedDatabase = &sqliteLoadedDatabase{} // interface assertion
+
+//
+
+func (f *TMainForm) SQLite_AddFromFile(path string) {
+
+	// TODO load in background thread to stop blocking the UI
+	db, err := sql.Open("sqlite3", path)
+	if err != nil {
+		vcl.ShowMessage(fmt.Sprintf("Failed to load database '%s': %s", path, err.Error()))
+		return
+	}
+
+	ld := &sqliteLoadedDatabase{
+		path:        path,
+		displayName: filepath.Base(path),
+		db:          db,
+	}
+
+	ld.nav = f.Buckets.Items().Add(nil, ld.displayName)
+	ld.nav.SetHasChildren(true) // dynamically populate in OnNavExpanding
+	navData := &navData{
+		ld:             ld,
+		childrenLoaded: false,      // will be loaded dynamically
+		bucketPath:     []string{}, // empty = root
+	}
+	ld.nav.SetData(unsafe.Pointer(navData))
+
+	f.dbs = append(f.dbs, ld)
+
+	ld.Keepalive(navData)
+}