[release/1.4.6] cmd, console: split off the console into a reusable package

(cherry picked from commit ffaf58f0a9)

cmd/utils/flags.go

@@ -302,7 +302,7 @@ var (
 		Name:  "exec",
 		Usage: "Execute JavaScript statement (only in combination with console/attach)",
 	}
-	PreLoadJSFlag = cli.StringFlag{
+	PreloadJSFlag = cli.StringFlag{
 		Name:  "preload",
 		Usage: "Comma separated list of JavaScript files to preload into the console",
 	}
@@ -864,3 +864,20 @@ func MakeChain(ctx *cli.Context) (chain *core.BlockChain, chainDb ethdb.Database
 	}
 	return chain, chainDb
 }
+
+// MakeConsolePreloads retrieves the absolute paths for the console JavaScript
+// scripts to preload before starting.
+func MakeConsolePreloads(ctx *cli.Context) []string {
+	// Skip preloading if there's nothing to preload
+	if ctx.GlobalString(PreloadJSFlag.Name) == "" {
+		return nil
+	}
+	// Otherwise resolve absolute paths and return them
+	preloads := []string{}
+
+	assets := ctx.GlobalString(JSpathFlag.Name)
+	for _, file := range strings.Split(ctx.GlobalString(PreloadJSFlag.Name), ",") {
+		preloads = append(preloads, common.AbsolutePath(assets, strings.TrimSpace(file)))
+	}
+	return preloads
+}