From 980eed2c3ffe3784747abd5dc6a6fdebbbe2caff Mon Sep 17 00:00:00 2001
From: Alexander Marsalek <amarsalek@iaik.tugraz.at>
Date: Thu, 22 Jul 2021 13:21:06 +0200
Subject: added getNextUnusedSignaturePlaceHolder => pdf over needs next unused
 placeholder issue #54

---
 .../SignatureFieldsAndPlaceHolderExtractor.java    | 41 +++++++++++++++++++---
 .../placeholder/SignaturePlaceholderExtractor.java |  5 ---
 .../impl/signing/pdfbox2/PADESPDFBOXSigner.java    |  2 +-
 3 files changed, 37 insertions(+), 11 deletions(-)

(limited to 'pdf-as-pdfbox-2/src/main/java/at')

diff --git a/pdf-as-pdfbox-2/src/main/java/at/gv/egiz/pdfas/lib/impl/pdfbox2/placeholder/SignatureFieldsAndPlaceHolderExtractor.java b/pdf-as-pdfbox-2/src/main/java/at/gv/egiz/pdfas/lib/impl/pdfbox2/placeholder/SignatureFieldsAndPlaceHolderExtractor.java
index ca620aec..63552c2a 100644
--- a/pdf-as-pdfbox-2/src/main/java/at/gv/egiz/pdfas/lib/impl/pdfbox2/placeholder/SignatureFieldsAndPlaceHolderExtractor.java
+++ b/pdf-as-pdfbox-2/src/main/java/at/gv/egiz/pdfas/lib/impl/pdfbox2/placeholder/SignatureFieldsAndPlaceHolderExtractor.java
@@ -8,6 +8,7 @@ import org.apache.pdfbox.pdmodel.interactive.form.PDAcroForm;
 import org.apache.pdfbox.pdmodel.interactive.form.PDField;
 import org.apache.pdfbox.pdmodel.interactive.form.PDSignatureField;
 
+import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
 
@@ -35,12 +36,27 @@ public class SignatureFieldsAndPlaceHolderExtractor {
     /*
     Needed by PDF-OVER
      */
-    public static SignaturePlaceholderData getNextSignaturePlaceHolder(PDDocument doc) {
+
+    /**
+     * Returns the next unused signature placeholder
+     * @param doc The document to be searched for signature placeholders
+     * @return The next unused signature placeholder or null in case there is none
+     */
+    public static SignaturePlaceholderData getNextUnusedSignaturePlaceHolder(PDDocument doc) {
         try {
-            SignaturePlaceholderExtractor signaturePlaceholderExtractor = new SignaturePlaceholderExtractor("1",
-                PlaceholderExtractorConstants.PLACEHOLDER_MATCH_MODE_SORTED, doc);
-            return signaturePlaceholderExtractor.extract(doc, "1",
-                PlaceholderExtractorConstants.PLACEHOLDER_MATCH_MODE_SORTED);
+            String placeholderId = "1";
+            int mode = PlaceholderExtractorConstants.PLACEHOLDER_MATCH_MODE_SORTED;
+            SignaturePlaceholderExtractor signaturePlaceholderExtractor = new SignaturePlaceholderExtractor( placeholderId,
+                mode, doc);
+            List<SignaturePlaceholderData> results = signaturePlaceholderExtractor.extractList(doc, placeholderId,
+                mode);
+            List<String> used = getExistingSignatureLocations(doc);
+            //return first not used
+            for(SignaturePlaceholderData result : results) {
+                if(!used.contains(result.getPlaceholderName()))
+                    return result;
+            }
+            return null;
         } catch (Exception e) {
             e.printStackTrace();
             return null;
@@ -69,4 +85,19 @@ public class SignatureFieldsAndPlaceHolderExtractor {
             return null;
         }
     }
+
+    public static List<String> getExistingSignatureLocations(PDDocument doc) {
+        List<String> existingLocations = new ArrayList<>();
+        try {
+            List <PDSignature> pdSignatureList =  doc.getSignatureDictionaries();
+            if(pdSignatureList.size() != 0) {
+                for(PDSignature sig : pdSignatureList) {
+                    existingLocations.add(sig.getLocation());
+                }
+            }
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+        return existingLocations;
+    }
 }
diff --git a/pdf-as-pdfbox-2/src/main/java/at/gv/egiz/pdfas/lib/impl/pdfbox2/placeholder/SignaturePlaceholderExtractor.java b/pdf-as-pdfbox-2/src/main/java/at/gv/egiz/pdfas/lib/impl/pdfbox2/placeholder/SignaturePlaceholderExtractor.java
index 71eef856..6df4f0b1 100644
--- a/pdf-as-pdfbox-2/src/main/java/at/gv/egiz/pdfas/lib/impl/pdfbox2/placeholder/SignaturePlaceholderExtractor.java
+++ b/pdf-as-pdfbox-2/src/main/java/at/gv/egiz/pdfas/lib/impl/pdfbox2/placeholder/SignaturePlaceholderExtractor.java
@@ -126,11 +126,6 @@ public class SignaturePlaceholderExtractor extends PDFStreamEngine implements Pl
 		this.doc = doc;
 	}
 
-//	public static List<SignaturePlaceholderData> getPlaceholders() {
-//		return placeholders;
-//	}
-
-
 	/**
 	 * Search the document for placeholder images and possibly included
 	 * additional info.<br/>
diff --git a/pdf-as-pdfbox-2/src/main/java/at/gv/egiz/pdfas/lib/impl/signing/pdfbox2/PADESPDFBOXSigner.java b/pdf-as-pdfbox-2/src/main/java/at/gv/egiz/pdfas/lib/impl/signing/pdfbox2/PADESPDFBOXSigner.java
index 3cf0853f..3e1b7d9a 100644
--- a/pdf-as-pdfbox-2/src/main/java/at/gv/egiz/pdfas/lib/impl/signing/pdfbox2/PADESPDFBOXSigner.java
+++ b/pdf-as-pdfbox-2/src/main/java/at/gv/egiz/pdfas/lib/impl/signing/pdfbox2/PADESPDFBOXSigner.java
@@ -162,7 +162,7 @@ public class PADESPDFBOXSigner implements IPdfSigner, IConfigurationConstants {
 			signature.setFilter(COSName.getPDFName(signer.getPDFFilter()));
 			signature.setSubFilter(COSName.getPDFName(signer.getPDFSubFilter()));
 //			SignaturePlaceholderData signaturePlaceholderDataInit =
-			placeholders =PlaceholderFilter.checkPlaceholderSignatureLocationList(pdfObject.getStatus(),
+			placeholders = PlaceholderFilter.checkPlaceholderSignatureLocationList(pdfObject.getStatus(),
 							pdfObject.getStatus().getSettings(), placeholder_id);
 
 //            placeholders = SignaturePlaceholderExtractor.getPlaceholders();
-- 
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