Refactor some utils.go; add another tool 'tiledump'

cmd/ctfetch/main.go

@@ -4,17 +4,14 @@
 package main
 
 import (
-	"bytes"
-	"compress/gzip"
-	"encoding/json"
 	"flag"
 	"fmt"
-	"io"
-	"net/http"
 	"os"
 	"strconv"
 	"strings"
 
+	"ctfetch/internal/utils"
+
 	"filippo.io/sunlight"
 	"golang.org/x/mod/sumdb/tlog"
 )
@@ -66,7 +63,7 @@ func main() {
 	// Try partial tile first
 	partialURL := logURL + "/" + partialPath
 	fmt.Fprintf(os.Stderr, "Trying: %s\n", partialURL)
-	tileData, err = fetchURL(partialURL)
+	tileData, err = utils.FetchURL(partialURL)
 	if err == nil {
 		fetchedPath = partialPath
 		fmt.Fprintf(os.Stderr, "Successfully fetched partial tile\n")
@@ -74,7 +71,7 @@ func main() {
 		// Fall back to full tile
 		fullURL := logURL + "/" + fullPath
 		fmt.Fprintf(os.Stderr, "Partial tile failed, trying: %s\n", fullURL)
-		tileData, err = fetchURL(fullURL)
+		tileData, err = utils.FetchURL(fullURL)
 		if err != nil {
 			fatal("failed to fetch tile: %v", err)
 		}
@@ -83,7 +80,7 @@ func main() {
 	}
 
 	// Decompress if needed
-	tileData, err = decompress(tileData)
+	tileData, err = utils.Decompress(tileData)
 	if err != nil {
 		fatal("failed to decompress tile: %v", err)
 	}
@@ -93,107 +90,17 @@ func main() {
 
 	if *dumpAll {
 		// Dump all entries in the tile
-		dumpAllEntries(tileData)
+		if err := utils.DumpAllEntries(tileData); err != nil {
+			fatal("%v", err)
+		}
 	} else {
 		// Dump only the specific entry at the position
-		dumpEntryAtPosition(tileData, int(positionInTile), leafIndex)
-	}
-}
-
-func fetchURL(url string) ([]byte, error) {
-	resp, err := http.Get(url)
-	if err != nil {
-		return nil, err
-	}
-	defer resp.Body.Close()
-
-	if resp.StatusCode != http.StatusOK {
-		return nil, fmt.Errorf("HTTP %d", resp.StatusCode)
-	}
-
-	return io.ReadAll(resp.Body)
-}
-
-func dumpAllEntries(tileData []byte) {
-	entryNum := 0
-	for len(tileData) > 0 {
-		e, remaining, err := sunlight.ReadTileLeaf(tileData)
-		if err != nil {
-			fatal("failed to read entry %d: %v", entryNum, err)
-		}
-		tileData = remaining
-
-		dumpEntry(e, entryNum)
-		fmt.Println()
-		entryNum++
-	}
-
-	fmt.Printf("Total entries: %d\n", entryNum)
-}
-
-func dumpEntryAtPosition(tileData []byte, position int, expectedIndex int64) {
-	entryNum := 0
-	for len(tileData) > 0 {
-		e, remaining, err := sunlight.ReadTileLeaf(tileData)
-		if err != nil {
-			fatal("failed to read entry %d: %v", entryNum, err)
-		}
-		tileData = remaining
-
-		if entryNum == position {
-			if e.LeafIndex != expectedIndex {
-				fmt.Fprintf(os.Stderr, "WARNING: Expected leaf index %d but found %d at position %d\n",
-					expectedIndex, e.LeafIndex, position)
-			}
-			dumpEntry(e, entryNum)
-			return
-		}
-		entryNum++
-	}
-
-	fatal("position %d not found in tile (only %d entries)", position, entryNum)
-}
-
-func dumpEntry(e *sunlight.LogEntry, entryNum int) {
-	fmt.Printf("=== Entry %d ===\n", entryNum)
-	fmt.Printf("Leaf Index: %d\n", e.LeafIndex)
-	fmt.Printf("Timestamp: %d\n", e.Timestamp)
-	fmt.Printf("Is Precert: %v\n", e.IsPrecert)
-
-	if e.IsPrecert {
-		fmt.Printf("Issuer Key Hash: %x\n", e.IssuerKeyHash)
-	}
-
-	fmt.Printf("Certificate: %d bytes\n", len(e.Certificate))
-	if e.PreCertificate != nil {
-		fmt.Printf("PreCertificate: %d bytes\n", len(e.PreCertificate))
-	}
-
-	fmt.Printf("Chain Fingerprints: %d entries\n", len(e.ChainFingerprints))
-	for i, fp := range e.ChainFingerprints {
-		fmt.Printf("  [%d]: %x\n", i, fp)
-	}
-
-	// Try to extract parsed certificate info
-	if trimmed, err := e.TrimmedEntry(); err == nil {
-		if data, err := json.MarshalIndent(trimmed, "  ", "  "); err == nil {
-			fmt.Printf("Parsed Certificate Info:\n  %s\n", data)
+		if err := utils.DumpEntryAtPosition(tileData, int(positionInTile), leafIndex); err != nil {
+			fatal("%v", err)
 		}
 	}
 }
 
-const maxCompressRatio = 100
-
-func decompress(data []byte) ([]byte, error) {
-	r, err := gzip.NewReader(bytes.NewReader(data))
-	if err != nil {
-		// Not gzipped, return as-is
-		return data, nil
-	}
-	maxSize := int64(len(data)) * maxCompressRatio
-	return io.ReadAll(io.LimitReader(r, maxSize))
-}
-
 func fatal(format string, args ...any) {
 	fmt.Fprintf(os.Stderr, "Error: "+format+"\n", args...)
 	os.Exit(1)