Merge pull request #2 from donatj/feature/ShowCreateTable

Adds SHOW CREATE TABLE Support

Author: donatj

cmd/sqlread/main.go

@@ -8,7 +8,7 @@ import (
 	"os"
 	"path/filepath"
 
-	"github.com/avvmoto/buf-readerat"
+	bufra "github.com/avvmoto/buf-readerat"
 	"github.com/donatj/sqlread"
 	"github.com/donatj/sqlread/mapcache"
 )
@@ -129,6 +129,12 @@ func interactive(tree sqlread.SummaryTree, buff io.ReaderAt) {
 			}
 		}
 
+		for _, sctbl := range qp.Tree.ShowCreateTables {
+			if err := showCreateTable(tree, sctbl, buff, w); err != nil {
+				log.Println(err)
+			}
+		}
+
 		if qp.Tree.Quit {
 			return
 		}

cmd/sqlread/query.go

@@ -77,7 +77,31 @@ func showColumns(tree sqlread.SummaryTree, sctbl string, w DataWriter) error {
 		return fmt.Errorf("table `%s` not found", sctbl)
 	}
 	for _, col := range tbl.Cols {
-		w.Write([]string{col.Name, col.Type})
+		err := w.Write([]string{col.Name, col.Type})
+		if err != nil {
+			return err
+		}
+	}
+	w.Flush()
+
+	return nil
+}
+
+func showCreateTable(tree sqlread.SummaryTree, sctbl string, buff io.ReaderAt, w DataWriter) error {
+	tbl, tok := tree[sctbl]
+	if !tok {
+		return fmt.Errorf("table `%s` not found", sctbl)
+	}
+
+	data := make([]byte, tbl.End.Pos-tbl.Start.Pos)
+	_, err := buff.ReadAt(data, tbl.Start.Pos)
+	if err != nil {
+		return err
+	}
+
+	err = w.Write([]string{string(data)})
+	if err != nil {
+		return err
 	}
 	w.Flush()
 

interpreter.go

@@ -26,6 +26,9 @@ func (intp *Intp) StartIntpState(l *lexer) state {
 		if l.hasPrefixI("COLUMNS") {
 			return intp.showColumnsIntpState
 		}
+		if l.hasPrefixI("CREATE") {
+			return intp.showCreateTableIntpState
+		}
 
 		l.emit(TIllegal)
 		return nil
@@ -42,6 +45,50 @@ func (intp *Intp) StartIntpState(l *lexer) state {
 	return nil
 }
 
+func (intp *Intp) showCreateTableIntpState(l *lexer) state {
+	l.pos += 6
+
+	if l.accept(whitespace) < 1 {
+		l.emit(TIllegal)
+		return nil
+	}
+
+	l.start = l.pos
+
+	if !l.hasPrefixI("TABLE") {
+		l.emit(TIllegal)
+		return nil
+	}
+	l.pos += 5
+	l.emit(TIntpShowCreateTable)
+	// TODO emit non-existing T_TABLE?
+
+	if l.accept(whitespace) < 1 {
+		l.emit(TIllegal)
+		return nil
+	}
+
+	l.start = l.pos
+
+	if eatIdentifier(l) {
+		l.emit(TIdentifier)
+	} else {
+		l.emit(TIllegal)
+		return nil
+	}
+
+	l.accept(whitespace)
+	l.start = l.pos
+
+	c := l.next()
+	if c != semi {
+		l.emit(TIllegal)
+		return nil
+	}
+
+	return nil
+}
+
 func (intp *Intp) showColumnsIntpState(l *lexer) state {
 	l.pos += 7
 	l.emit(TIntpShowColumns)

lexitemtype_string.go

@@ -8,6 +8,10 @@ import (
 	"github.com/donatj/sqlread"
 )
 
+// CacheVersion is incremented when the structure of the cache changes
+// such that it is no longer compatible.
+const CacheVersion = 1
+
 type MapCache struct {
 	sqlfile *os.File
 }
@@ -19,6 +23,7 @@ func New(sqlfile *os.File) *MapCache {
 }
 
 var (
+	// ErrCacheMiss is an error when a valid cache is not found
 	ErrCacheMiss = errors.New("cache miss")
 )
 
@@ -43,6 +48,10 @@ func (m *MapCache) Get() (sqlread.SummaryTree, error) {
 		return nil, ErrCacheMiss
 	}
 
+	if v.Version != CacheVersion {
+		return nil, ErrCacheMiss
+	}
+
 	return v.Tree, nil
 }
 
@@ -55,6 +64,7 @@ func (m *MapCache) Store(s sqlread.SummaryTree) error {
 
 	e := json.NewEncoder(cf)
 	err = e.Encode(cacheInfo{
+		Version:  CacheVersion,
 		FileSize: m.getFileSize(),
 		Tree:     s,
 	})
@@ -80,6 +90,7 @@ func (m *MapCache) getFileSize() int64 {
 }
 
 type cacheInfo struct {
+	Version  int
 	FileSize int64
 	Tree     sqlread.SummaryTree
 }

mapcache/cache.go

@@ -7,10 +7,13 @@ type Query struct {
 }
 
 type QueryTree struct {
-	Queries     []Query
-	ShowTables  uint
-	ShowColumns []string
-	Quit        bool
+	Queries []Query
+
+	ShowTables       uint
+	ShowColumns      []string
+	ShowCreateTables []string
+
+	Quit bool
 }
 
 type QueryParser struct {
@@ -47,6 +50,10 @@ func (q *QueryParser) ParseStart(p *Parser) parseState {
 			return q.parseShowColumns
 		}
 
+		if isOfAny(c, TIntpShowCreateTable) {
+			return q.parseShowCreateTable
+		}
+
 		if isOfAny(c, TIntpQuit) {
 			return q.parseQuit
 		}
@@ -107,7 +114,7 @@ func (q *QueryParser) parseShowColumns(p *Parser) parseState {
 		return nil
 	}
 	if !isOfAny(y, TIdentifier) {
-		p.errorUnexpectedLex(x, TIdentifier)
+		p.errorUnexpectedLex(y, TIdentifier)
 		return nil
 	}
 
@@ -116,6 +123,22 @@ func (q *QueryParser) parseShowColumns(p *Parser) parseState {
 	return q.ParseStart
 }
 
+func (q *QueryParser) parseShowCreateTable(p *Parser) parseState {
+	y, ok := p.scan()
+	if !ok {
+		p.errorUnexpectedEOF()
+		return nil
+	}
+	if !isOfAny(y, TIdentifier) {
+		p.errorUnexpectedLex(y, TIdentifier)
+		return nil
+	}
+
+	q.Tree.ShowCreateTables = append(q.Tree.ShowCreateTables, identValue(y))
+
+	return q.ParseStart
+}
+
 func (q *QueryParser) parseSelect(p *Parser) parseState {
 	qry := &Query{
 		Columns: make([]string, 0),

query.go

@@ -51,6 +51,7 @@ const (
 
 	TIntpShowTables
 	TIntpShowColumns
+	TIntpShowCreateTable
 
 	TIntpQuit
 )