dcrsqlite: create DB-file parent directory when necessary

Fixes decred#515

.gitignore

@@ -31,3 +31,5 @@ ffldb_stake*/
 *.pprof
 testnet/
 .DS_Store
+
+testdata/

db/dcrsqlite/.gitignore

@@ -0,0 +1 @@
+test.data

db/dcrsqlite/dcrsqlite_test.go

@@ -2,12 +2,13 @@ package dcrsqlite
 
 import (
 	"os"
+
 	"path/filepath"
 	"testing"
 )
 
 // Clears target folder content
-func removeContents(dir string) error {
+func RemoveContents(dir string) error {
 	d, err := os.Open(dir)
 	if err != nil {
 		return err
@@ -32,7 +33,7 @@ const (
 )
 
 // Returns path of a temporary directory used by these tests to store some data
-func getTempFolderPath(t *testing.T) string {
+func TempFolderPath(t *testing.T) string {
 	testDir, err := filepath.Abs(defaultDataDirname)
 	if err != nil {
 		t.Fatalf("Failed to produce DB-test folder path: %v", err)
@@ -41,24 +42,21 @@ func getTempFolderPath(t *testing.T) string {
 }
 
 // Ensures we run our test in a clean room. Removes all files created by any of these tests in the temp directory.
-func resetTempFolder(t *testing.T) {
-	testFolderPath := getTempFolderPath(t)
-
-	removeContents(testFolderPath)
+func ResetTempFolder(t *testing.T) {
+	testFolderPath := TempFolderPath(t)
 	err := os.RemoveAll(testFolderPath)
-
 	//Failed to clear test-files
 	if err != nil {
 		t.Fatalf("Failed to clear temp folder %v", err)
 	}
 }
 
 // Creates a path to a file inside the temp directory
-func getFilePathInsideTempDir(t *testing.T, pathInsideTempFolder string) string {
-	tempDir := getTempFolderPath(t)
-
+func FilePathInsideTempDir(t *testing.T, pathInsideTempFolder string) string {
+	tempDir := TempFolderPath(t)
 	targetPath := filepath.Join(tempDir, pathInsideTempFolder)
 	targetPath, err := filepath.Abs(targetPath)
+
 	if err != nil {
 		t.Fatalf("Failed to build a path %v", err)
 	}
@@ -68,8 +66,8 @@ func getFilePathInsideTempDir(t *testing.T, pathInsideTempFolder string) string
 // TestMissingParentFolder ensures InitDB() is able to create a new DB-file parent directory if necessary
 // See https://github.com/decred/dcrdata/issues/515
 func TestMissingParentFolder(t *testing.T) {
-	resetTempFolder(t)
-	targetDBFile := getFilePathInsideTempDir(t, "x/y/z/"+defaultDBFileName)
+	ResetTempFolder(t)
+	targetDBFile := FilePathInsideTempDir(t, "x/y/z/"+defaultDBFileName)
 	dbInfo := &DBInfo{FileName: targetDBFile}
 	db, err := InitDB(dbInfo)
 

db/dcrsqlite/sqlite.go

@@ -6,15 +6,16 @@ package dcrsqlite
 import (
 	"database/sql"
 	"fmt"
+	"os"
+	"path/filepath"
 	"strconv"
 	"strings"
 	"sync"
 
-	"github.com/decred/slog"
-
 	"github.com/decred/dcrd/wire"
 	apitypes "github.com/decred/dcrdata/api/types"
 	"github.com/decred/dcrdata/blockdata"
+	"github.com/decred/slog"
 	_ "github.com/mattn/go-sqlite3" // register sqlite driver with database/sql
 )
 
@@ -146,7 +147,19 @@ func NewDB(db *sql.DB) (*DB, error) {
 // InitDB creates a new DB instance from a DBInfo containing the name of the
 // file used to back the underlying sql database.
 func InitDB(dbInfo *DBInfo) (*DB, error) {
-	db, err := sql.Open("sqlite3", dbInfo.FileName)
+	dbPath, err := filepath.Abs(dbInfo.FileName)
+	if err != nil {
+		return nil, err
+	}
+
+	// Ensures target DB-file has a parent folder
+	parent := filepath.Dir(dbPath)
+	err = os.MkdirAll(parent, 0755)
+	if err != nil {
+		return nil, err
+	}
+
+	db, err := sql.Open("sqlite3", dbPath)
 	if err != nil || db == nil {
 		return nil, err
 	}