Persist applet cookies to /config/saves

The JSObject stand-in kept cookies in memory, so saves were lost when the
game restarted. Write them to a file the session manager can sync, with the
policy granting only the agent jar access to that directory.

streaming/streamer/README.md

@@ -37,6 +37,6 @@ Selkies restarts the game when it exits (`RESTART_APP`).
 
 `appletviewer` lacks two things applets got from the browser's Java plugin, so
 the image adds them: a `netscape.javascript.JSObject` stand-in whose window has
-a working `document.cookie`, and a policy allowing HTTP requests through the
+a `document.cookie` that persists to `/config/saves/cookies.txt`, and a policy allowing HTTP requests through the
 game server's proxy. The same jar (`applet-support/`) is loaded as a Java agent
 that removes appletviewer's menu bar and status line.

streaming/streamer/applet-support/netscape/javascript/Document.java

@@ -1,25 +1,37 @@
 package netscape.javascript;
 
+import java.io.File;
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.security.AccessController;
+import java.security.PrivilegedAction;
+import java.util.ArrayList;
 import java.util.LinkedHashMap;
+import java.util.List;
 import java.util.Map;
 
-/** A document whose cookie member behaves like document.cookie in a browser. */
+/**
+ * A document whose cookie member behaves like document.cookie in a browser.
+ * Cookies persist to ~/saves/cookies.txt, one name=value pair per line.
+ */
 class Document extends JSObject {
+    private final File file = AccessController.doPrivileged(
+            (PrivilegedAction<File>) () -> new File(System.getProperty("user.home"), "saves/cookies.txt"));
     private final Map<String, String> cookies = new LinkedHashMap<String, String>();
 
+    Document() {
+        for (String line : AccessController.doPrivileged((PrivilegedAction<List<String>>) this::read)) {
+            put(line);
+        }
+    }
+
     @Override
     public Object getMember(String name) throws JSException {
         if (!name.equals("cookie")) {
             return super.getMember(name);
         }
-        StringBuilder sb = new StringBuilder();
-        for (Map.Entry<String, String> cookie : cookies.entrySet()) {
-            if (sb.length() > 0) {
-                sb.append("; ");
-            }
-            sb.append(cookie.getKey()).append('=').append(cookie.getValue());
-        }
-        return sb.toString();
+        return String.join("; ", lines());
     }
 
     @Override
@@ -28,10 +40,44 @@ class Document extends JSObject {
             super.setMember(name, value);
             return;
         }
-        String pair = String.valueOf(value).split(";", 2)[0];
-        int eq = pair.indexOf('=');
-        if (eq > 0) {
-            cookies.put(pair.substring(0, eq).trim(), pair.substring(eq + 1).trim());
+        if (put(String.valueOf(value).split(";", 2)[0])) {
+            AccessController.doPrivileged((PrivilegedAction<Void>) this::write);
         }
     }
+
+    private boolean put(String pair) {
+        int eq = pair.indexOf('=');
+        if (eq <= 0) {
+            return false;
+        }
+        cookies.put(pair.substring(0, eq).trim(), pair.substring(eq + 1).trim());
+        return true;
+    }
+
+    private List<String> lines() {
+        List<String> lines = new ArrayList<String>();
+        for (Map.Entry<String, String> cookie : cookies.entrySet()) {
+            lines.add(cookie.getKey() + "=" + cookie.getValue());
+        }
+        return lines;
+    }
+
+    private List<String> read() {
+        try {
+            return file.isFile() ? Files.readAllLines(file.toPath(), StandardCharsets.UTF_8) : new ArrayList<String>();
+        } catch (IOException e) {
+            System.err.println("Failed to read " + file + ": " + e);
+            return new ArrayList<String>();
+        }
+    }
+
+    private Void write() {
+        try {
+            file.getParentFile().mkdirs();
+            Files.write(file.toPath(), lines(), StandardCharsets.UTF_8);
+        } catch (IOException e) {
+            System.err.println("Failed to write " + file + ": " + e);
+        }
+        return null;
+    }
 }

streaming/streamer/root/opt/flashpoint/applet.policy

@@ -1,3 +1,9 @@
 grant {
     permission java.net.URLPermission "http:*", "*:*";
 };
+
+grant codeBase "file:/opt/flashpoint/applet-support.jar" {
+    permission java.util.PropertyPermission "user.home", "read";
+    permission java.io.FilePermission "${user.home}${/}saves", "read,write";
+    permission java.io.FilePermission "${user.home}${/}saves${/}-", "read,write";
+};