Merge pull request #67 from digitorus/revert-66-revert-65-fix-catalog-entries-discarded

fix: Existing catalog entries are being discarded; this ensures that all catalog entries are copied to the new updated catalog.

sign/pdfcatalog.go

@@ -2,7 +2,11 @@ package sign
 
 import (
 	"bytes"
+	"fmt"
+	"io"
 	"strconv"
+
+	"github.com/digitorus/pdf"
 )
 
 func (context *SignContext) createCatalog() ([]byte, error) {
@@ -28,32 +32,18 @@ func (context *SignContext) createCatalog() ([]byte, error) {
 	// catalog_buffer.WriteString(" /Version /2.0")
 	// }
 
-	// Retrieve the root and check for necessary keys in one loop
+	// Retrieve the root, its pointer and set the root string
 	root := context.PDFReader.Trailer().Key("Root")
 	rootPtr := root.GetPtr()
 	context.CatalogData.RootString = strconv.Itoa(int(rootPtr.GetID())) + " " + strconv.Itoa(int(rootPtr.GetGen())) + " R"
 
-	foundPages, foundNames := false, false
+	// Copy over existing catalog entries except for type and AcroForum
 	for _, key := range root.Keys() {
-		switch key {
+		if key != "Type" && key != "AcroForm" {
-		case "Pages":
+			_, _ = fmt.Fprintf(&catalog_buffer, "  /%s ", key)
-			foundPages = true
+			context.serializeCatalogEntry(&catalog_buffer, rootPtr.GetID(), root.Key(key))
-		case "Names":
+			catalog_buffer.WriteString("\n")
-			foundNames = true
 		}
-		if foundPages && foundNames {
-			break
-		}
-	}
-
-	// Add Pages and Names references if they exist
-	if foundPages {
-		pages := root.Key("Pages").GetPtr()
-		catalog_buffer.WriteString("  /Pages " + strconv.Itoa(int(pages.GetID())) + " " + strconv.Itoa(int(pages.GetGen())) + " R\n")
-	}
-	if foundNames {
-		names := root.Key("Names").GetPtr()
-		catalog_buffer.WriteString("  /Names " + strconv.Itoa(int(names.GetID())) + " " + strconv.Itoa(int(names.GetGen())) + " R\n")
 	}
 
 	// Start the AcroForm dictionary with /NeedAppearances
@@ -123,3 +113,53 @@ func (context *SignContext) createCatalog() ([]byte, error) {
 
 	return catalog_buffer.Bytes(), nil
 }
+
+// serializeCatalogEntry takes a pdf.Value and serializes it to the given writer.
+func (context *SignContext) serializeCatalogEntry(w io.Writer, rootObjId uint32, value pdf.Value) {
+	if ptr := value.GetPtr(); ptr.GetID() != rootObjId {
+		// Indirect object
+		_, _ = fmt.Fprintf(w, "%d %d R", ptr.GetID(), ptr.GetGen())
+		return
+	}
+
+	// Direct object
+	switch value.Kind() {
+	case pdf.String:
+		_, _ = fmt.Fprintf(w, "(%s)", value.RawString())
+	case pdf.Null:
+		_, _ = fmt.Fprint(w, "null")
+	case pdf.Bool:
+		if value.Bool() {
+			_, _ = fmt.Fprint(w, "true")
+		} else {
+			_, _ = fmt.Fprint(w, "false")
+		}
+	case pdf.Integer:
+		_, _ = fmt.Fprintf(w, "%d", value.Int64())
+	case pdf.Real:
+		_, _ = fmt.Fprintf(w, "%f", value.Float64())
+	case pdf.Name:
+		_, _ = fmt.Fprintf(w, "/%s", value.Name())
+	case pdf.Dict:
+		_, _ = fmt.Fprint(w, "<<")
+		for idx, key := range value.Keys() {
+			if idx > 0 {
+				_, _ = fmt.Fprint(w, " ") // Space between items
+			}
+			_, _ = fmt.Fprintf(w, "/%s ", key)
+			context.serializeCatalogEntry(w, rootObjId, value.Key(key))
+		}
+		_, _ = fmt.Fprint(w, ">>")
+	case pdf.Array:
+		_, _ = fmt.Fprint(w, "[")
+		for idx := range value.Len() {
+			if idx > 0 {
+				_, _ = fmt.Fprint(w, " ") // Space between items
+			}
+			context.serializeCatalogEntry(w, rootObjId, value.Index(idx))
+		}
+		_, _ = fmt.Fprint(w, "]")
+	case pdf.Stream:
+		panic("stream cannot be a direct object")
+	}
+}

sign/pdfcatalog_test.go

@@ -15,17 +15,17 @@ var testFiles = []struct {
 	{
 		file: "../testfiles/testfile20.pdf",
 		expectedCatalogs: map[CertType]string{
-			CertificationSignature: "<<\n  /Type /Catalog\n  /Pages 3 0 R\n  /AcroForm <<\n    /Fields [10 0 R]\n    /SigFlags 3\n  >>\n>>\n",
+			CertificationSignature: "<<\n  /Type /Catalog\n  /Metadata 2 0 R\n  /Pages 3 0 R\n  /AcroForm <<\n    /Fields [10 0 R]\n    /SigFlags 3\n  >>\n>>\n",
-			UsageRightsSignature:   "<<\n  /Type /Catalog\n  /Pages 3 0 R\n  /AcroForm <<\n    /Fields [10 0 R]\n    /SigFlags 1\n  >>\n>>\n",
+			UsageRightsSignature:   "<<\n  /Type /Catalog\n  /Metadata 2 0 R\n  /Pages 3 0 R\n  /AcroForm <<\n    /Fields [10 0 R]\n    /SigFlags 1\n  >>\n>>\n",
-			ApprovalSignature:      "<<\n  /Type /Catalog\n  /Pages 3 0 R\n  /AcroForm <<\n    /Fields [10 0 R]\n    /SigFlags 3\n  >>\n>>\n",
+			ApprovalSignature:      "<<\n  /Type /Catalog\n  /Metadata 2 0 R\n  /Pages 3 0 R\n  /AcroForm <<\n    /Fields [10 0 R]\n    /SigFlags 3\n  >>\n>>\n",
 		},
 	},
 	{
 		file: "../testfiles/testfile21.pdf",
 		expectedCatalogs: map[CertType]string{
-			CertificationSignature: "<<\n  /Type /Catalog\n  /Pages 9 0 R\n  /Names 6 0 R\n  /AcroForm <<\n    /Fields [16 0 R]\n    /SigFlags 3\n  >>\n>>\n",
+			CertificationSignature: "<<\n  /Type /Catalog\n  /Metadata 8 0 R\n  /Names 6 0 R\n  /Pages 9 0 R\n  /AcroForm <<\n    /Fields [16 0 R]\n    /SigFlags 3\n  >>\n>>\n",
-			UsageRightsSignature:   "<<\n  /Type /Catalog\n  /Pages 9 0 R\n  /Names 6 0 R\n  /AcroForm <<\n    /Fields [16 0 R]\n    /SigFlags 1\n  >>\n>>\n",
+			UsageRightsSignature:   "<<\n  /Type /Catalog\n  /Metadata 8 0 R\n  /Names 6 0 R\n  /Pages 9 0 R\n  /AcroForm <<\n    /Fields [16 0 R]\n    /SigFlags 1\n  >>\n>>\n",
-			ApprovalSignature:      "<<\n  /Type /Catalog\n  /Pages 9 0 R\n  /Names 6 0 R\n  /AcroForm <<\n    /Fields [16 0 R]\n    /SigFlags 3\n  >>\n>>\n",
+			ApprovalSignature:      "<<\n  /Type /Catalog\n  /Metadata 8 0 R\n  /Names 6 0 R\n  /Pages 9 0 R\n  /AcroForm <<\n    /Fields [16 0 R]\n    /SigFlags 3\n  >>\n>>\n",
 		},
 	},
 }