From: Colin P. McCabe <cmccabe@apache.org>
Date: Mon, 19 Jun 2023 20:02:17 +0000 (-0700)
Subject: pickrand.go: add -n flag
X-Git-Url: http://club.cc.cmu.edu/~cmccabe/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=af6e83b9253100d04607d2b41897defad1c0e6f4;p=cmccabe-bin

pickrand.go: add -n flag
---

diff --git a/pickrand.go b/pickrand.go
index 79c4076..e51bf26 100644
--- a/pickrand.go
+++ b/pickrand.go
@@ -3,22 +3,42 @@ package main
 import (
 	"bytes"
 	"crypto/rand"
+    "flag"
 	"fmt"
 	"math/big"
 	"os"
 	"path/filepath"
+	"time"
 )
 
 func main() {
-	root := "."
-	if len(os.Args) > 1 {
-		root = os.Args[1]
-	}
+    flag.Usage = func() {
+        fmt.Fprintf(os.Stdout, "pickrand.go: picks a random file.\n")
+        fmt.Fprintf(os.Stdout, "\n")
+        flag.PrintDefaults()
+    }
+    prevDays := flag.Int("n", 0, "The number of days back to look.")
+    flag.Parse()
+    var maxDuration time.Duration
+    if (*prevDays != 0) {
+        maxDuration = time.Duration(int64(*prevDays) * (24 * 60 * 60 * 1e9))
+    }
+    
+	root := flag.Arg(0)
+    if (root == "") {
+        root = "."
+    }
 	files := make([]string, 0, 32)
 	err := filepath.Walk(root, func(p string, f os.FileInfo, err error) error {
 		if err != nil {
 			return err
 		}
+        if maxDuration != 0 {
+            var duration = time.Now().Sub(f.ModTime())
+            if duration > maxDuration {
+                return nil
+            }
+        }
 		if !f.IsDir() {
 			files = append(files, p)
 		}
@@ -28,6 +48,10 @@ func main() {
 		fmt.Fprintf(os.Stderr, "** Error: %s\n", err.Error())
 		os.Exit(1)
 	}
+    if len(files) == 0 {
+		fmt.Fprintf(os.Stderr, "No matching files found.\n")
+		os.Exit(1)
+    }
 	var b [16]byte
 	_, err = rand.Read(b[:])
 	if err != nil {