From 98e5999761bf97f9dba8487d70afcdca23540e24 Mon Sep 17 00:00:00 2001
From: Kevin Atkinson <k@kevina.org>
Date: Sun, 26 Aug 2018 20:10:19 -0400
Subject: [PATCH] Factor out boiler plate code for PostRun in "ipfs filestore
 ls".

License: MIT
Signed-off-by: Kevin Atkinson <k@kevina.org>
---
 core/commands/commands.go  | 40 ++++++++++++++++++++++++++++++++++++++
 core/commands/filestore.go | 37 +++++++----------------------------
 2 files changed, 47 insertions(+), 30 deletions(-)

diff --git a/core/commands/commands.go b/core/commands/commands.go
index 51c707c6e..a89b279f7 100644
--- a/core/commands/commands.go
+++ b/core/commands/commands.go
@@ -8,6 +8,7 @@ package commands
 import (
 	"fmt"
 	"io"
+	"os"
 	"sort"
 	"strings"
 
@@ -149,3 +150,42 @@ func unwrapOutput(i interface{}) (interface{}, error) {
 
 	return <-ch, nil
 }
+
+type nonFatalError string
+
+// streamRes is a helper function to stream results, that possibly
+// contain with non-fatal, the helper function is allowed to panic on
+// internal errors
+func streamRes(procVal func(interface{}, io.Writer) nonFatalError) func(cmds.Response, cmds.ResponseEmitter) error {
+	return func(res cmds.Response, re cmds.ResponseEmitter) (err error) {
+		defer func() {
+			if r := recover(); r != nil {
+				err = fmt.Errorf("internal error: %v", r)
+			}
+			re.Close()
+		}()
+
+		var errors bool
+		for {
+			v, err := res.Next()
+			if err != nil {
+				if err == io.EOF {
+					break
+				}
+				return err
+			}
+
+			errorMsg := procVal(v, os.Stdout)
+
+			if errorMsg != "" {
+				errors = true
+				fmt.Fprintf(os.Stderr, "%s\n", errorMsg)
+			}
+		}
+
+		if errors {
+			return fmt.Errorf("errors while displaying some entries")
+		}
+		return nil
+	}
+}
diff --git a/core/commands/filestore.go b/core/commands/filestore.go
index a45e01ef9..deb7520d2 100644
--- a/core/commands/filestore.go
+++ b/core/commands/filestore.go
@@ -4,7 +4,6 @@ import (
 	"context"
 	"fmt"
 	"io"
-	"os"
 
 	oldCmds "github.com/ipfs/go-ipfs/commands"
 	lgc "github.com/ipfs/go-ipfs/commands/legacy"
@@ -73,36 +72,14 @@ The output is:
 		return res.Emit(out)
 	},
 	PostRun: cmds.PostRunMap{
-		cmds.CLI: func(res cmds.Response, re cmds.ResponseEmitter) error {
-			var errors bool
-			for {
-				v, err := res.Next()
-				if err != nil {
-					if err == io.EOF {
-						break
-					}
-					return err
-				}
-
-				r, ok := v.(*filestore.ListRes)
-				if !ok {
-					return e.New(e.TypeErr(r, v))
-				}
-
-				if r.ErrorMsg != "" {
-					errors = true
-					fmt.Fprintf(os.Stderr, "%s\n", r.ErrorMsg)
-				} else {
-					fmt.Fprintf(os.Stdout, "%s\n", r.FormatLong())
-				}
+		cmds.CLI: streamRes(func(v interface{}, out io.Writer) nonFatalError {
+			r := v.(*filestore.ListRes)
+			if r.ErrorMsg != "" {
+				return nonFatalError(r.ErrorMsg)
 			}
-
-			if errors {
-				return fmt.Errorf("errors while displaying some entries")
-			}
-
-			return nil
-		},
+			fmt.Fprintf(out, "%s\n", r.FormatLong())
+			return ""
+		}),
 	},
 	Type: filestore.ListRes{},
 }