105 lines
2.0 KiB
Go
105 lines
2.0 KiB
Go
package vm
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import (
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"fmt"
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"os"
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"strings"
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. "godb/internals/buffer"
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)
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type MetaCommandResults int
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const (
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MetaCommandSuccess MetaCommandResults = iota
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MetaCommandUnrecognised
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)
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type PrepareResults int
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const (
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PrepareSuccess PrepareResults = iota
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PrepareUnrecognised
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PrepareSyntaxError
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)
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type statementType int
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const (
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StatementSelect statementType = iota
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StatementInsert
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)
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type row struct {
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id uint
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username string
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email string
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}
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type Statement struct {
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stype statementType
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row row
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}
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const (
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_pageSize = 4096
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maxPages = 100
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)
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type Table struct {
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numOfRows uint
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pages [maxPages]any
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}
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func NewStatement() *Statement {
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return &Statement{0, row{0, "", ""}}
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}
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func NewTable() *Table {
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newTable := Table{numOfRows: 0}
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for i := range maxPages {
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newTable.pages[i] = nil
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}
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return &newTable
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}
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func DoMetaCommands(inputBuffer *InputBuffer) MetaCommandResults {
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metacommand := MetaCommandUnrecognised
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if inputBuffer.Buffer == ".exit" {
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fmt.Println("bye!")
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os.Exit(0)
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} else {
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metacommand = MetaCommandUnrecognised
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}
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return metacommand
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}
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func (statement *Statement) PrepareStatements(inputBuffer *InputBuffer) PrepareResults {
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if strings.HasPrefix(inputBuffer.Buffer, "insert") {
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argsAssigned, err := fmt.Sscanf(inputBuffer.Buffer, "insert %d %s %s", &statement.row.id, &statement.row.username, &statement.row.email)
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if err != nil {
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fmt.Println("error parsing insert statement")
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fmt.Println(err.Error())
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}
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if argsAssigned > 3 {
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return PrepareSyntaxError
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}
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statement.stype = StatementInsert
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return PrepareSuccess
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}
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if strings.HasPrefix(inputBuffer.Buffer, "select") {
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statement.stype = StatementSelect
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return PrepareSuccess
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}
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return PrepareUnrecognised
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}
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func (statement *Statement) ExecuteStatement(table *Table) {
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switch statement.stype {
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case StatementInsert:
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fmt.Println("This is where the logic of insert statement should go")
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case StatementSelect:
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fmt.Println("This is where the logic of select statement should go")
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}
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}
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