AP_Filesystem: support full direcotry listing in ROMFS

libraries/AP_Filesystem/AP_Filesystem.cpp

@@ -64,6 +64,7 @@ const AP_Filesystem::Backend AP_Filesystem::backends[] = {
     { nullptr, fs_local },
 #if AP_FILESYSTEM_ROMFS_ENABLED
     { "@ROMFS/", fs_romfs },
+    { "@ROMFS", fs_romfs },
 #endif
 #if AP_FILESYSTEM_PARAM_ENABLED
     { "@PARAM/", fs_param },

libraries/AP_Filesystem/AP_Filesystem_ROMFS.cpp

@@ -159,6 +159,15 @@ void *AP_Filesystem_ROMFS::opendir(const char *pathname)
     if (!dir[idx].path) {
         return nullptr;
     }
+
+    // Take a sneak peek and reset
+    const char *name = AP_ROMFS::dir_list(dir[idx].path, dir[idx].ofs);
+    dir[idx].ofs = 0;
+    if (!name) {
+        // Directory does not exist
+        return nullptr;
+    }
+
     return (void*)&dir[idx];
 }
 
@@ -174,12 +183,28 @@ struct dirent *AP_Filesystem_ROMFS::readdir(void *dirp)
         return nullptr;
     }
     const uint32_t plen = strlen(dir[idx].path);
-    if (strncmp(name, dir[idx].path, plen) != 0 || name[plen] != '/') {
-        return nullptr;
-    }
+    if (plen > 0) {
+        // Offset to get just file/directory name
         name += plen + 1;
-    dir[idx].de.d_type = DT_REG;
+    }
+
+    // Copy full name
     strncpy(dir[idx].de.d_name, name, sizeof(dir[idx].de.d_name));
+
+    const char* slash = strchr(name, '/');
+    if (slash == nullptr) {
+        // File
+        dir[idx].de.d_type = DT_REG;
+
+    } else {
+        // Directory
+        dir[idx].de.d_type = DT_DIR;
+
+        // Add null termination after directory name
+        const size_t index = slash - name;
+        dir[idx].de.d_name[index] = 0;
+    }
+
     return &dir[idx].de;
 }