From 8a45ceccdc4f0909ba21d6966259fee838ed40af Mon Sep 17 00:00:00 2001
From: Hermes Agent <hermes@nousresearch.com>
Date: Wed, 3 Jun 2026 12:36:14 +0200
Subject: [PATCH] fix: prefer descriptor formats (.cue/.ccd) over raw data
 (.img/.bin) for DOSBox CD mounting

DOSBox's imgmount works best with descriptors because they contain track layout
info (audio tracks, subchannel data, copy protection). Raw .img/.bin mounts
lose this info, making the filesystem inaccessible and causing 'Illegal command'
when trying to run executables from the CD.
---
 .../java/com/dostalgia/UploadResource.java    | 33 +++++++++++--------
 1 file changed, 19 insertions(+), 14 deletions(-)

diff --git a/src/main/java/com/dostalgia/UploadResource.java b/src/main/java/com/dostalgia/UploadResource.java
index ac32106..af22e34 100644
--- a/src/main/java/com/dostalgia/UploadResource.java
+++ b/src/main/java/com/dostalgia/UploadResource.java
@@ -574,6 +574,8 @@ public class UploadResource {
         sb.append("[dos]\nxms=true\nems=true\numb=true\n\n");
         sb.append("[autoexec]\n@echo off\nmount c .\n");
         // Mount CD images as D:, E:, …
+        // Prefer descriptor formats (.cue, .ccd) over raw data (.img, .bin)
+        // DOSBox needs descriptors for proper track layout and filesystem access.
         Set<String> seenDirs = new java.util.HashSet<>();
         char driveLetter = 'D';
         for (String img : cdImages) {
@@ -581,19 +583,20 @@ public class UploadResource {
             String parentDir = slashIdx >= 0 ? img.substring(0, slashIdx) : "";
             if (seenDirs.contains(parentDir)) continue;
             String imgLower = img.toLowerCase();
-            // Skip descriptor formats if a data format exists in the same directory
-            if (imgLower.endsWith(".cue") || imgLower.endsWith(".ccd")) {
-                boolean hasData = cdImages.stream().anyMatch(i -> {
+            // Skip raw data files when a descriptor exists in the same directory
+            if (imgLower.endsWith(".img") || imgLower.endsWith(".bin")) {
+                boolean hasDescriptor = cdImages.stream().anyMatch(i -> {
                     int is = i.lastIndexOf('/');
                     String ip = is >= 0 ? i.substring(0, is) : "";
                     String il = i.toLowerCase();
                     return ip.equals(parentDir)
-                        && (il.endsWith(".img") || il.endsWith(".iso") || il.endsWith(".bin"));
+                        && (il.endsWith(".cue") || il.endsWith(".ccd"));
                 });
-                if (hasData) continue;
+                if (hasDescriptor) continue;
             }
             seenDirs.add(parentDir);
-            String flags = imgLower.endsWith(".bin") ? " -t cdrom -fs iso" : " -t cdrom";
+            String flags = (imgLower.endsWith(".bin") && !imgLower.endsWith(".cue"))
+                ? " -t cdrom -fs iso" : " -t cdrom";
             sb.append("imgmount ").append(driveLetter).append(" \"").append(img).append("\"").append(flags).append("\n");
             driveLetter++;
         }
@@ -651,8 +654,9 @@ public class UploadResource {
         sb.append("@echo off\n");
         sb.append("mount c .\n");
         // Mount CD images as D:, E:, … so games can find their CD.
-        // Deduplicate by parent directory — prefer data formats (.img, .iso, .bin)
-        // over descriptor formats (.cue, .ccd) which can have FILE path case-mismatch.
+        // Deduplicate by parent directory — prefer descriptor formats (.cue, .ccd)
+        // over raw data formats (.img, .bin). DOSBox needs descriptors for proper
+        // track layout (audio tracks, subchannel data, copy protection).
         Set<String> seenDirs = new java.util.HashSet<>();
         char driveLetter = 'D';
         for (String img : cdImages) {
@@ -660,19 +664,20 @@ public class UploadResource {
             String parentDir = slashIdx >= 0 ? img.substring(0, slashIdx) : "";
             if (seenDirs.contains(parentDir)) continue;
             String imgLower = img.toLowerCase();
-            // Skip descriptor formats if a data format exists in the same directory
-            if (imgLower.endsWith(".cue") || imgLower.endsWith(".ccd")) {
-                boolean hasData = cdImages.stream().anyMatch(i -> {
+            // Skip raw data files when a descriptor exists in the same directory
+            if (imgLower.endsWith(".img") || imgLower.endsWith(".bin")) {
+                boolean hasDescriptor = cdImages.stream().anyMatch(i -> {
                     int is = i.lastIndexOf('/');
                     String ip = is >= 0 ? i.substring(0, is) : "";
                     String il = i.toLowerCase();
                     return ip.equals(parentDir)
-                        && (il.endsWith(".img") || il.endsWith(".iso") || il.endsWith(".bin"));
+                        && (il.endsWith(".cue") || il.endsWith(".ccd"));
                 });
-                if (hasData) continue;
+                if (hasDescriptor) continue;
             }
             seenDirs.add(parentDir);
-            String flags = imgLower.endsWith(".bin") ? " -t cdrom -fs iso" : " -t cdrom";
+            String flags = (imgLower.endsWith(".bin") && !imgLower.endsWith(".cue"))
+                ? " -t cdrom -fs iso" : " -t cdrom";
             sb.append("imgmount ").append(driveLetter).append(" \"").append(img).append("\"").append(flags).append("\n");
             driveLetter++;
         }