Moved sub programs into folder cmd to clean up project structure.

cmd/mtdbconverter/sqlite.go

@@ -0,0 +1,175 @@
+// Copyright 2014 by Sascha L. Teichmann
+// Use of this source code is governed by the MIT license
+// that can be found in the LICENSE file.
+
+package main
+
+import (
+	"database/sql"
+	"errors"
+	"os"
+
+	"bitbucket.org/s_l_teichmann/mtredisalize/common"
+
+	_ "github.com/mattn/go-sqlite3"
+)
+
+const (
+	createSql = "CREATE TABLE blocks (pos INT NOT NULL PRIMARY KEY, data BLOB)"
+	insertSql = "INSERT INTO blocks (pos, data) VALUES (?, ?)"
+	deleteSql = "DELETE FROM blocks"
+	selectSql = "SELECT pos, data FROM blocks"
+)
+
+var ErrDatabaseNotExists = errors.New("Database does not exists.")
+
+const blocksPerTx = 128
+
+type (
+	SQLiteBlockProducer struct {
+		db       *sql.DB
+		rows     *sql.Rows
+		splitter common.KeySplitter
+	}
+
+	SQLiteBlockConsumer struct {
+		db         *sql.DB
+		insertStmt *sql.Stmt
+		tx         *sql.Tx
+		txCounter  int
+		joiner     common.KeyJoiner
+	}
+)
+
+func fileExists(path string) bool {
+	_, err := os.Stat(path)
+	return !os.IsNotExist(err)
+}
+
+func NewSQLiteBlockConsumer(
+	path string,
+	joiner common.KeyJoiner) (sbc *SQLiteBlockConsumer, err error) {
+
+	createNew := !fileExists(path)
+
+	var db *sql.DB
+	if db, err = sql.Open("sqlite3", path); err != nil {
+		return
+	}
+
+	if createNew {
+		if _, err = db.Exec(createSql); err != nil {
+			db.Close()
+			return
+		}
+	} else {
+		if _, err = db.Exec(deleteSql); err != nil {
+			db.Close()
+			return
+		}
+	}
+
+	var insertStmt *sql.Stmt
+	if insertStmt, err = db.Prepare(insertSql); err != nil {
+		db.Close()
+		return
+	}
+
+	var tx *sql.Tx
+	if tx, err = db.Begin(); err != nil {
+		insertStmt.Close()
+		db.Close()
+		return
+	}
+
+	sbc = &SQLiteBlockConsumer{
+		db:         db,
+		insertStmt: insertStmt,
+		tx:         tx,
+		joiner:     joiner}
+
+	return
+}
+
+func (sbc *SQLiteBlockConsumer) Close() error {
+	sbc.tx.Commit()
+	sbc.insertStmt.Close()
+	return sbc.db.Close()
+}
+
+func (sbc *SQLiteBlockConsumer) getTx() (tx *sql.Tx, err error) {
+	if sbc.txCounter >= blocksPerTx {
+		sbc.txCounter = 0
+		if err = sbc.tx.Commit(); err != nil {
+			return
+		}
+		if sbc.tx, err = sbc.db.Begin(); err != nil {
+			return
+		}
+	}
+	sbc.txCounter++
+	tx = sbc.tx
+	return
+}
+
+func (sbc *SQLiteBlockConsumer) Consume(block *common.Block) (err error) {
+	var tx *sql.Tx
+	if tx, err = sbc.getTx(); err != nil {
+		return
+	}
+	_, err = tx.Stmt(sbc.insertStmt).Exec(sbc.joiner(block.Coord), block.Data)
+	return
+}
+
+func NewSQLiteBlockProducer(
+	path string,
+	splitter common.KeySplitter) (sbp *SQLiteBlockProducer, err error) {
+
+	if !fileExists(path) {
+		err = ErrDatabaseNotExists
+		return
+	}
+
+	var db *sql.DB
+	if db, err = sql.Open("sqlite3", path); err != nil {
+		return
+	}
+
+	var rows *sql.Rows
+	if rows, err = db.Query(selectSql); err != nil {
+		db.Close()
+		return
+	}
+
+	sbp = &SQLiteBlockProducer{
+		db:       db,
+		rows:     rows,
+		splitter: splitter}
+
+	return
+}
+
+func (sbp *SQLiteBlockProducer) Next(block *common.Block) (err error) {
+	if sbp.rows == nil {
+		err = common.ErrNoMoreBlocks
+		return
+	}
+	if sbp.rows.Next() {
+		var key int64
+		if err = sbp.rows.Scan(&key, &block.Data); err == nil {
+			block.Coord = sbp.splitter(key)
+		}
+	} else {
+		sbp.rows.Close()
+		sbp.rows = nil
+		err = common.ErrNoMoreBlocks
+	}
+	return
+}
+
+func (sbp *SQLiteBlockProducer) Close() error {
+	if sbp.rows != nil {
+		sbp.rows.Close()
+	}
+	return sbp.db.Close()
+}