icns

commit 1bc682f12cfdddaf33a639c218ffd361c95e33db
parent 5fdb3ed2de4345cf12601fc28b0f5badff095f80
Author: Jack Mordaunt <jackmordaunt@gmail.com>
Date:   Tue, 30 Jan 2018 17:30:59 +0100

[+] Enable unix piping.

Diffstat:
M
cmd/main.go
 | 
58
++++++++++++++++++++++++++++++++++------------------------
A
cmd/pipe.go
 | 
21
+++++++++++++++++++++

2 files changed, 55 insertions(+), 24 deletions(-)
diff --git a/cmd/main.go b/cmd/main.go
@@ -2,6 +2,7 @@ package main
 
 import (
 	"image"
+	"io"
 	"log"
 	"os"
 	"path/filepath"
@@ -13,35 +14,48 @@ import (
 	"github.com/spf13/pflag"
 )
 
-var fs = afero.NewOsFs()
+var (
+	fs     = afero.NewOsFs()
+	piping bool
+	input  io.Reader
+	output io.Writer
+)
 
 func main() {
 	var (
-		input  = pflag.StringP("input", "i", "", "Input image for conversion to icns (jpg|png)")
-		output = pflag.StringP("output", "o", "", "Output path, defaults to <path/to/image>.icns")
-		resize = pflag.IntP("resize", "r", 5, "Quality of resize algorithm. Values range from 0 to 5, fastest to highest quality. Defaults to highest quality.")
+		inputPath  = pflag.StringP("input", "i", "", "Input image for conversion to icns (jpg|png)")
+		outputPath = pflag.StringP("output", "o", "", "Output path, defaults to <path/to/image>.icns")
+		resize     = pflag.IntP("resize", "r", 5, "Quality of resize algorithm. Values range from 0 to 5, fastest to slowest execution time. Defaults to slowest for best quality.")
 	)
 	pflag.Parse()
-	in, out, algorithm := sanitiseInputs(*input, *output, *resize)
-	sourcef, err := fs.Open(in)
-	if err != nil {
-		log.Fatalf("opening source image: %v", err)
+	in, out, algorithm := sanitiseInputs(*inputPath, *outputPath, *resize)
+	if !piping {
+		if in == "" {
+			usage()
+			os.Exit(0)
+		}
+		sourcef, err := fs.Open(in)
+		if err != nil {
+			log.Fatalf("opening source image: %v", err)
+		}
+		defer sourcef.Close()
+		input = sourcef
+		if err := fs.MkdirAll(filepath.Dir(out), 0755); err != nil {
+			log.Fatalf("preparing output directory: %v", err)
+		}
+		outputf, err := fs.Create(out)
+		if err != nil {
+			log.Fatalf("creating icns file: %v", err)
+		}
+		defer outputf.Close()
+		output = outputf
 	}
-	defer sourcef.Close()
-	img, _, err := image.Decode(sourcef)
+	img, _, err := image.Decode(input)
 	if err != nil {
 		log.Fatalf("decoding image: %v", err)
 	}
-	if err := fs.MkdirAll(filepath.Dir(out), 0755); err != nil {
-		log.Fatalf("preparing output directory: %v", err)
-	}
-	outputf, err := fs.Create(out)
-	if err != nil {
-		log.Fatalf("creating icns file: %v", err)
-	}
-	defer outputf.Close()
 	if err := icns.EncodeWithInterpolationFunction(
-		outputf,
+		output,
 		img,
 		algorithm,
 	); err != nil {
@@ -54,11 +68,7 @@ func sanitiseInputs(
 	outputPath string,
 	resize int,
 ) (string, string, icns.InterpolationFunction) {
-	if inputPath == "" {
-		pflag.Usage()
-		os.Exit(0)
-	}
-	if outputPath == "" {
+	if inputPath != "" && outputPath == "" {
 		outputPath = changeExtensionTo(inputPath, "icns")
 	}
 	if filepath.Ext(outputPath) == "" {
diff --git a/cmd/pipe.go b/cmd/pipe.go
@@ -0,0 +1,21 @@
+package main
+
+import (
+	"fmt"
+	"os"
+)
+
+func init() {
+	info, err := os.Stdin.Stat()
+	if err != nil {
+		panic(fmt.Sprintf("getting info on stdin file descriptor: %v", err))
+	}
+	if (info.Mode() & os.ModeCharDevice) == os.ModeCharDevice {
+		return
+	}
+	if info.Size() > 0 {
+		piping = true
+		input = os.Stdin
+		output = os.Stdout
+	}
+}