A better way to print prettified json syntax error msg

pkg/quick/errorutil.go

@@ -0,0 +1,96 @@
+/*
+ * Quick - Quick key value store for config files and persistent state files
+ *
+ * Minio Client (C) 2015 Minio, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package quick
+
+import (
+	"bufio"
+	"bytes"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+
+	"github.com/olekukonko/ts"
+)
+
+const errorFmt = "%5d: %s <--  "
+
+// FormatJSONSyntaxError generates a pretty printed json syntax error since
+// golang doesn't provide an easy way to report the location of the error
+func FormatJSONSyntaxError(data io.Reader, sErr *json.SyntaxError) error {
+	if sErr == nil {
+		return nil
+	}
+
+	var readLine bytes.Buffer
+
+	bio := bufio.NewReader(data)
+	errLine := int64(1)
+	readBytes := int64(0)
+
+	// termWidth is set to a default one to use when we are
+	// not able to calculate terminal width via OS syscalls
+	termWidth := 25
+
+	// errorShift is the length of the minimum needed place for
+	// error msg accessoires, like <--, etc.. We calculate it
+	// dynamically to avoid an eventual bug after modifying errorFmt
+	errorShift := len(fmt.Sprintf(errorFmt, 1, ""))
+
+	if termSize, err := ts.GetSize(); err == nil {
+		termWidth = termSize.Col()
+	}
+
+	for {
+		b, err := bio.ReadByte()
+		if err != nil {
+			if err != io.EOF {
+				return err
+			}
+			break
+		}
+		readBytes++
+		if readBytes > sErr.Offset {
+			break
+		}
+		switch b {
+		case '\n':
+			readLine.Reset()
+			errLine++
+		case '\t':
+			readLine.WriteByte(' ')
+		case '\r':
+			break
+		default:
+			readLine.WriteByte(b)
+		}
+	}
+
+	lineLen := readLine.Len()
+	idx := lineLen - termWidth + errorShift
+	if idx < 0 || idx > lineLen-1 {
+		idx = 0
+	}
+
+	errorStr := fmt.Sprintf("JSON syntax error at line %d, col %d : %s.\n",
+		errLine, readLine.Len(), sErr)
+	errorStr += fmt.Sprintf(errorFmt, errLine, readLine.String()[idx:])
+
+	return errors.New(errorStr)
+}

pkg/quick/quick.go

@@ -19,6 +19,7 @@
 package quick
 
 import (
+	"bytes"
 	"encoding/json"
 	"fmt"
 	"io/ioutil"
@@ -144,8 +145,13 @@ func Load(filename string, data interface{}) (Config, *probe.Error) {
 
 	err = json.Unmarshal(fileData, &data)
 	if err != nil {
+		switch err := err.(type) {
+		case *json.SyntaxError:
+			return nil, probe.NewError(FormatJSONSyntaxError(bytes.NewReader(fileData), err))
+		default:
 			return nil, probe.NewError(err)
 		}
+	}
 
 	config, perr := New(data)
 	if perr != nil {
@@ -182,8 +188,13 @@ func (d *config) Load(filename string) *probe.Error {
 
 	err = json.Unmarshal(fileData, d.data)
 	if err != nil {
+		switch err := err.(type) {
+		case *json.SyntaxError:
+			return probe.NewError(FormatJSONSyntaxError(bytes.NewReader(fileData), err))
+		default:
 			return probe.NewError(err)
 		}
+	}
 
 	if err := CheckData(d.data); err != nil {
 		return err.Trace()

vendor.json

@@ -86,6 +86,13 @@
 			"revision": "ee386baecc113eef2b8945df429120a5aec319ef",
 			"revisionTime": "2015-08-19T11:23:55-07:00"
 		},
+		{
+			"canonical": "github.com/olekukonko/ts",
+			"comment": "",
+			"local": "vendor/github.com/olekukonko/ts",
+			"revision": "ecf753e7c962639ab5a1fb46f7da627d4c0a04b8",
+			"revisionTime": "2014-04-12T15:01:45-07:00"
+		},
 		{
 			"canonical": "github.com/rs/cors",
 			"comment": "",

vendor/github.com/olekukonko/ts/LICENCE

@@ -0,0 +1,19 @@
+Copyright (C) 2014 by Oleku Konko
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.

vendor/github.com/olekukonko/ts/README.md

@@ -0,0 +1,28 @@
+ts (Terminal Size)
+==
+
+[![Build Status](https://travis-ci.org/olekukonko/ts.png?branch=master)](https://travis-ci.org/olekukonko/ts) [![Total views](https://sourcegraph.com/api/repos/github.com/olekukonko/ts/counters/views.png)](https://sourcegraph.com/github.com/olekukonko/ts)
+
+Simple go Application to get Terminal Size. So Many Implementations do not support windows but `ts` has full windows support.
+Run `go get github.com/olekukonko/ts` to download and install
+
+#### Example
+
+```go
+package main
+
+import (
+	"fmt"
+	"github.com/olekukonko/ts"
+)
+
+func main() {
+	size, _ := ts.GetSize()
+	fmt.Println(size.Col())  // Get Width
+	fmt.Println(size.Row())  // Get Height
+	fmt.Println(size.PosX()) // Get X position
+	fmt.Println(size.PosY()) // Get Y position
+}
+```
+
+[See Documentation](http://godoc.org/github.com/olekukonko/ts)

vendor/github.com/olekukonko/ts/doc.go

@@ -0,0 +1,36 @@
+// Copyright 2014 Oleku Konko All rights reserved.
+// Use of this source code is governed by a MIT
+// license that can be found in the LICENSE file.
+
+// This module is a Terminal  API for the Go Programming Language.
+// The protocols were written in pure Go and works on windows and unix systems
+
+/**
+
+Simple go Application to get Terminal Size. So Many Implementations do not support windows but `ts` has full windows support.
+Run `go get github.com/olekukonko/ts` to download and install
+
+Installation
+
+Minimum requirements are Go 1.1+ with fill Windows support
+
+Example
+
+	package main
+
+	import (
+		"fmt"
+		"github.com/olekukonko/ts"
+	)
+
+	func main() {
+		size, _ := ts.GetSize()
+		fmt.Println(size.Col())  // Get Width
+		fmt.Println(size.Row())  // Get Height
+		fmt.Println(size.PosX()) // Get X position
+		fmt.Println(size.PosY()) // Get Y position
+	}
+
+**/
+
+package ts

vendor/github.com/olekukonko/ts/ts.go

@@ -0,0 +1,36 @@
+// Copyright 2014 Oleku Konko All rights reserved.
+// Use of this source code is governed by a MIT
+// license that can be found in the LICENSE file.
+
+// This module is a Terminal  API for the Go Programming Language.
+// The protocols were written in pure Go and works on windows and unix systems
+
+package ts
+
+// Return System Size
+type Size struct {
+	row  uint16
+	col  uint16
+	posX uint16
+	posY uint16
+}
+
+// Get Terminal Width
+func (w Size) Col() int {
+	return int(w.col)
+}
+
+// Get Terminal Height
+func (w Size) Row() int {
+	return int(w.row)
+}
+
+// Get Position X
+func (w Size) PosX() int {
+	return int(w.posX)
+}
+
+// Get Position Y
+func (w Size) PosY() int {
+	return int(w.posY)
+}

vendor/github.com/olekukonko/ts/ts_darwin.go

@@ -0,0 +1,14 @@
+// +build darwin
+
+// Copyright 2014 Oleku Konko All rights reserved.
+// Use of this source code is governed by a MIT
+// license that can be found in the LICENSE file.
+
+// This module is a Terminal  API for the Go Programming Language.
+// The protocols were written in pure Go and works on windows and unix systems
+
+package ts
+
+const (
+	TIOCGWINSZ = 0x40087468
+)

vendor/github.com/olekukonko/ts/ts_linux.go

@@ -0,0 +1,13 @@
+// +build linux
+
+// Copyright 2014 Oleku Konko All rights reserved.
+// Use of this source code is governed by a MIT
+// license that can be found in the LICENSE file.
+
+// This module is a Terminal  API for the Go Programming Language.
+// The protocols were written in pure Go and works on windows and unix systems
+package ts
+
+const (
+	TIOCGWINSZ = 0x5413
+)

vendor/github.com/olekukonko/ts/ts_other.go

@@ -0,0 +1,14 @@
+// +build !windows,!darwin,!freebsd,!netbsd,!openbsd,!linux
+
+// Copyright 2014 Oleku Konko All rights reserved.
+// Use of this source code is governed by a MIT
+// license that can be found in the LICENSE file.
+
+// This module is a Terminal  API for the Go Programming Language.
+// The protocols were written in pure Go and works on windows and unix systems
+
+package ts
+
+const (
+	TIOCGWINSZ = 0
+)

vendor/github.com/olekukonko/ts/ts_test.go

@@ -0,0 +1,32 @@
+// Copyright 2014 Oleku Konko All rights reserved.
+// Use of this source code is governed by a MIT
+// license that can be found in the LICENSE file.
+
+// This module is a Terminal  API for the Go Programming Language.
+// The protocols were written in pure Go and works on windows and unix systems
+
+package ts
+
+import (
+	"fmt"
+	"testing"
+)
+
+func ExampleGetSize() {
+	size, _ := GetSize()
+	fmt.Println(size.Col())  // Get Width
+	fmt.Println(size.Row())  // Get Height
+	fmt.Println(size.PosX()) // Get X position
+	fmt.Println(size.PosY()) // Get Y position
+}
+
+func TestSize(t *testing.T) {
+	size, err := GetSize()
+
+	if err != nil {
+		t.Fatal(err)
+	}
+	if size.Col() == 0 || size.Row() == 0 {
+		t.Fatalf("Screen Size Failed")
+	}
+}

vendor/github.com/olekukonko/ts/ts_unix.go

@@ -0,0 +1,14 @@
+// +build  freebsd netbsd openbsd
+
+// Copyright 2014 Oleku Konko All rights reserved.
+// Use of this source code is governed by a MIT
+// license that can be found in the LICENSE file.
+
+// This module is a Terminal  API for the Go Programming Language.
+// The protocols were written in pure Go and works on windows and unix systems
+
+package ts
+
+const (
+	TIOCGWINSZ = 0x40087468
+)

vendor/github.com/olekukonko/ts/ts_windows.go

@@ -0,0 +1,64 @@
+// +build windows
+
+// Copyright 2014 Oleku Konko All rights reserved.
+// Use of this source code is governed by a MIT
+// license that can be found in the LICENSE file.
+
+// This module is a Terminal  API for the Go Programming Language.
+// The protocols were written in pure Go and works on windows and unix systems
+
+package ts
+
+import (
+	"syscall"
+	"unsafe"
+)
+
+var (
+	kernel32 = syscall.NewLazyDLL("kernel32.dll")
+
+	// Retrieves information about the specified console screen buffer.
+	// See http://msdn.microsoft.com/en-us/library/windows/desktop/ms683171(v=vs.85).aspx
+	screenBufferInfo = kernel32.NewProc("GetConsoleScreenBufferInfo")
+)
+
+//   Contains information about a console screen buffer.
+// http://msdn.microsoft.com/en-us/library/windows/desktop/ms682093(v=vs.85).aspx
+type CONSOLE_SCREEN_BUFFER_INFO struct {
+	DwSize              COORD
+	DwCursorPosition    COORD
+	WAttributes         uint16
+	SrWindow            SMALL_RECT
+	DwMaximumWindowSize COORD
+}
+
+// Defines the coordinates of a character cell in a console screen buffer.
+// The origin of the coordinate system (0,0) is at the top, left cell of the buffer.
+// See http://msdn.microsoft.com/en-us/library/windows/desktop/ms682119(v=vs.85).aspx
+type COORD struct {
+	X, Y uint16
+}
+
+// Defines the coordinates of the upper left and lower right corners of a rectangle.
+// See http://msdn.microsoft.com/en-us/library/windows/desktop/ms686311(v=vs.85).aspx
+type SMALL_RECT struct {
+	Left, Top, Right, Bottom uint16
+}
+
+func GetSize() (ws Size, err error) {
+	var info CONSOLE_SCREEN_BUFFER_INFO
+	rc, _, err := screenBufferInfo.Call(
+		uintptr(syscall.Stdout),
+		uintptr(unsafe.Pointer(&info)))
+
+	if rc == 0 {
+		return ws, err
+	}
+
+	ws = Size{info.SrWindow.Bottom,
+		info.SrWindow.Right,
+		info.DwCursorPosition.X,
+		info.DwCursorPosition.Y}
+
+	return ws, nil
+}

vendor/github.com/olekukonko/ts/ts_x.go

@@ -0,0 +1,46 @@
+// +build !windows
+
+// Copyright 2014 Oleku Konko All rights reserved.
+// Use of this source code is governed by a MIT
+// license that can be found in the LICENSE file.
+
+// This module is a Terminal API for the Go Programming Language.
+// The protocols were written in pure Go and works on windows and unix systems
+
+package ts
+
+import (
+	"syscall"
+	"unsafe"
+)
+
+// Get Windows Size
+func GetSize() (ws Size, err error) {
+	_, _, ec := syscall.Syscall(syscall.SYS_IOCTL,
+		uintptr(syscall.Stdout),
+		uintptr(TIOCGWINSZ),
+		uintptr(unsafe.Pointer(&ws)))
+
+	err = getError(ec)
+
+	if TIOCGWINSZ == 0 && err != nil {
+		ws = Size{80, 25, 0, 0}
+	}
+	return ws, err
+}
+
+func getError(ec interface{}) (err error) {
+	switch v := ec.(type) {
+
+	case syscall.Errno: // Some implementation return syscall.Errno number
+		if v != 0 {
+			err = syscall.Errno(v)
+		}
+
+	case error: // Some implementation return error
+		err = ec.(error)
+	default:
+		err = nil
+	}
+	return
+}