From 3f17e8c3c8f0cc79fc7c0080f65d8b39da74d543 Mon Sep 17 00:00:00 2001
From: Luck <git@lucko.me>
Date: Sun, 12 Feb 2017 17:19:16 +0000
Subject: [PATCH] Test verbose filters before registering them (#178)

---
 .../common/commands/misc/VerboseCommand.java  |  6 ++++
 .../luckperms/common/constants/Message.java   |  1 +
 .../luckperms/common/debug/DebugListener.java | 36 +++++++++++++++++++
 default-lang.yml                              |  1 +
 4 files changed, 44 insertions(+)

diff --git a/common/src/main/java/me/lucko/luckperms/common/commands/misc/VerboseCommand.java b/common/src/main/java/me/lucko/luckperms/common/commands/misc/VerboseCommand.java
index 3b3d9879..dd2fac10 100644
--- a/common/src/main/java/me/lucko/luckperms/common/commands/misc/VerboseCommand.java
+++ b/common/src/main/java/me/lucko/luckperms/common/commands/misc/VerboseCommand.java
@@ -65,6 +65,12 @@ public class VerboseCommand extends SingleCommand {
             }
 
             String filter = filters.isEmpty() ? "" : filters.stream().collect(Collectors.joining(" "));
+
+            if (!DebugListener.isValidFilter(filter)) {
+                Message.VERBOSE_INVALID_FILTER.send(sender, filter);
+                return CommandResult.FAILURE;
+            }
+
             boolean notify = !mode.equals("record");
 
             plugin.getDebugHandler().register(sender, filter, notify);
diff --git a/common/src/main/java/me/lucko/luckperms/common/constants/Message.java b/common/src/main/java/me/lucko/luckperms/common/constants/Message.java
index 99984e4f..6a43dfb7 100644
--- a/common/src/main/java/me/lucko/luckperms/common/constants/Message.java
+++ b/common/src/main/java/me/lucko/luckperms/common/constants/Message.java
@@ -96,6 +96,7 @@ public enum Message {
     /*
      * Commands
      */
+    VERBOSE_INVALID_FILTER("&cInvalid verbose filter: &f{0}", true),
     VERBOSE_ON("&bVerbose checking output set to &aTRUE &bfor all permissions.", true),
     VERBOSE_ON_QUERY("&bVerbose checking output set to &aTRUE &bfor permissions matching the following filters: &f{0}", true),
     VERBOSE_OFF("&bVerbose checking output set to &cFALSE&b.", true),
diff --git a/common/src/main/java/me/lucko/luckperms/common/debug/DebugListener.java b/common/src/main/java/me/lucko/luckperms/common/debug/DebugListener.java
index 5919020d..12c31646 100644
--- a/common/src/main/java/me/lucko/luckperms/common/debug/DebugListener.java
+++ b/common/src/main/java/me/lucko/luckperms/common/debug/DebugListener.java
@@ -116,6 +116,42 @@ public class DebugListener {
         return false;
     }
 
+    public static boolean isValidFilter(String filter) {
+        if (filter.equals("")) {
+            return true;
+        }
+
+        ScriptEngine engine = Scripting.getScriptEngine();
+        if (engine == null) {
+            return false;
+        }
+
+        StringTokenizer tokenizer = new StringTokenizer(filter, " |&()!", true);
+        StringBuilder expression = new StringBuilder();
+
+        while (tokenizer.hasMoreTokens()) {
+            String token = tokenizer.nextToken();
+            if (!isDelim(token)) {
+                token = "true"; // dummy result
+            }
+
+            expression.append(token);
+        }
+
+        try {
+            String exp = expression.toString().replace("&", "&&").replace("|", "||");
+            String result = engine.eval(exp).toString();
+            if (!result.equals("true") && !result.equals("false")) {
+                throw new IllegalArgumentException(exp + " - " + result);
+            }
+
+            return true;
+
+        } catch (Throwable t) {
+            return false;
+        }
+    }
+
     private static boolean isDelim(String token) {
         return token.equals(" ") || token.equals("|") || token.equals("&") || token.equals("(") || token.equals(")") || token.equals("!");
     }
diff --git a/default-lang.yml b/default-lang.yml
index 28d04267..ca2cf4af 100644
--- a/default-lang.yml
+++ b/default-lang.yml
@@ -50,6 +50,7 @@ use-inherit-command: "Use the 'parent add' command instead of specifying the nod
 
 
 
+verbose-invalid-filter: "&cInvalid verbose filter: &f{0}"
 verbose-on: "&bVerbose checking output set to &aTRUE &bfor all permissions."
 verbose-on_query: "&bVerbose checking output set to &aTRUE &bfor permissions matching the following filters: &f{0}"
 verbose-off: "&bVerbose checking output set to &cFALSE&b."