PoC rule expressions

ATTRIBUTION.md

@@ -57,3 +57,4 @@ FairEmail uses parts or all of:
 * [ZXing](https://github.com/zxing/zxing). Copyright (C) 2014 ZXing authors. [Apache License 2.0](https://github.com/zxing/zxing/blob/master/LICENSE).
 * [commonmark-java](https://github.com/commonmark/commonmark-java). Copyright (c) 2015, Atlassian Pty Ltd. All rights reserved. [BSD-2-Clause license](https://github.com/commonmark/commonmark-java/blob/main/LICENSE.txt).
 * [flexmark-java](https://github.com/vsch/flexmark-java). Copyright (c) 2016-2018, Vladimir Schneider. All rights reserved. [BSD-2-Clause license](https://github.com/vsch/flexmark-java/blob/master/LICENSE.txt).
+* [EvalEx](https://github.com/ezylang/EvalEx). Copyright 2012-2022 Udo Klimaschewski. [Apache License 2.0](https://github.com/ezylang/EvalEx/blob/main/LICENSE).

app/build.gradle

@@ -587,6 +587,7 @@ dependencies {
     def ws_version = "2.14"
     def tinylog_version = "2.6.2"
     def zxing_version = "3.5.3"
+    def evalex_version = "3.2.0"
 
     // https://mvnrepository.com/artifact/com.android.tools/desugar_jdk_libs?repo=google
     coreLibraryDesugaring "com.android.tools:desugar_jdk_libs:$desugar_version"
@@ -857,4 +858,7 @@ dependencies {
     // https://github.com/zxing/zxing
     // https://mvnrepository.com/artifact/com.google.zxing/core
     implementation "com.google.zxing:core:$zxing_version"
+
+    // https://github.com/ezylang/EvalEx
+    implementation "com.ezylang:EvalEx:$evalex_version"
 }

app/proguard-rules.pro

@@ -161,3 +161,6 @@
 -dontwarn java.lang.**
 -dontwarn javax.naming.**
 -dontwarn sun.reflect.Reflection
+
+#EvalEx
+-dontwarn lombok.Generated

app/src/main/assets/ATTRIBUTION.md

@@ -57,3 +57,4 @@ FairEmail uses parts or all of:
 * [ZXing](https://github.com/zxing/zxing). Copyright (C) 2014 ZXing authors. [Apache License 2.0](https://github.com/zxing/zxing/blob/master/LICENSE).
 * [commonmark-java](https://github.com/commonmark/commonmark-java). Copyright (c) 2015, Atlassian Pty Ltd. All rights reserved. [BSD-2-Clause license](https://github.com/commonmark/commonmark-java/blob/main/LICENSE.txt).
 * [flexmark-java](https://github.com/vsch/flexmark-java). Copyright (c) 2016-2018, Vladimir Schneider. All rights reserved. [BSD-2-Clause license](https://github.com/vsch/flexmark-java/blob/master/LICENSE.txt).
+* [EvalEx](https://github.com/ezylang/EvalEx). Copyright 2012-2022 Udo Klimaschewski. [Apache License 2.0](https://github.com/ezylang/EvalEx/blob/main/LICENSE).

app/src/main/java/eu/faircode/email/EntityRule.java

@@ -21,6 +21,8 @@ package eu.faircode.email;
 
 import static androidx.room.ForeignKey.CASCADE;
 
+import static com.ezylang.evalex.operators.OperatorIfc.OPERATOR_PRECEDENCE_COMPARISON;
+
 import android.Manifest;
 import android.content.ContentResolver;
 import android.content.Context;
@@ -41,6 +43,15 @@ import androidx.room.ForeignKey;
 import androidx.room.Index;
 import androidx.room.PrimaryKey;
 
+import com.ezylang.evalex.EvaluationException;
+import com.ezylang.evalex.Expression;
+import com.ezylang.evalex.config.ExpressionConfiguration;
+import com.ezylang.evalex.data.EvaluationValue;
+import com.ezylang.evalex.operators.AbstractOperator;
+import com.ezylang.evalex.operators.InfixOperator;
+import com.ezylang.evalex.parser.ParseException;
+import com.ezylang.evalex.parser.Token;
+
 import org.json.JSONException;
 import org.json.JSONObject;
 import org.jsoup.nodes.Document;
@@ -62,6 +73,7 @@ import java.util.Date;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Locale;
+import java.util.Map;
 import java.util.Objects;
 import java.util.UUID;
 import java.util.regex.Matcher;
@@ -151,6 +163,10 @@ public class EntityRule {
     private static final int MAX_NOTES_LENGTH = 512; // characters
     private static final int URL_TIMEOUT = 15 * 1000; // milliseconds
 
+    private static final List<String> EXPR_VARIABLES = Collections.unmodifiableList(Arrays.asList(
+            "sender", "subject"
+    ));
+
     static boolean needsHeaders(EntityMessage message, List<EntityRule> rules) {
         return needsHeaders(rules);
     }
@@ -183,6 +199,16 @@ public class EntityRule {
                     }
                     return true;
                 }
+                if (jcondition.has("expression")) {
+                    Expression expression = getExpression(rule, null);
+                    if (expression != null)
+                        for (String variable : expression.getUsedVariables())
+                            if ("body".equals(what) && "body".equalsIgnoreCase(variable))
+                                return true;
+                            else if ("header".equals(what) && "header".equalsIgnoreCase(variable))
+                                return true;
+                    return false;
+                }
             } catch (Throwable ex) {
                 Log.e(ex);
             }
@@ -463,6 +489,19 @@ public class EntityRule {
                     return false;
             }
 
+            Expression expression = getExpression(this, message);
+            if (expression != null) {
+                for (String variable : expression.getUsedVariables())
+                    if ("header".equalsIgnoreCase(variable) && message.headers == null)
+                        throw new IllegalArgumentException(context.getString(R.string.title_rule_no_headers));
+
+                Log.i("EXPR evaluating " + jcondition.getString("expression"));
+                Boolean result = expression.evaluate().getBooleanValue();
+                Log.i("EXPR evaluated=" + result);
+                if (!Boolean.TRUE.equals(result))
+                    return false;
+            }
+
             // Safeguard
             if (jsender == null &&
                     jrecipient == null &&
@@ -472,9 +511,10 @@ public class EntityRule {
                     jbody == null &&
                     jdate == null &&
                     jschedule == null &&
-                    !jcondition.has("younger"))
+                    !jcondition.has("younger") &&
+                    !jcondition.has("expression"))
                 return false;
-        } catch (JSONException ex) {
+        } catch (JSONException | ParseException | EvaluationException ex) {
             Log.e(ex);
             return false;
         }
@@ -593,6 +633,58 @@ public class EntityRule {
         return matched;
     }
 
+    @InfixOperator(precedence = OPERATOR_PRECEDENCE_COMPARISON)
+    public static class ContainsOperator extends AbstractOperator {
+        @Override
+        public EvaluationValue evaluate(
+                Expression expression, Token operatorToken, EvaluationValue... operands) {
+            String op1 = operands[0].getStringValue();
+            String op2 = operands[1].getStringValue();
+            Log.i("EXPR " + op1 + " CONTAINS " + op2);
+            return expression.convertValue(
+                    !TextUtils.isEmpty(op1) && !TextUtils.isEmpty(op2) &&
+                            op1.toLowerCase().contains(op2.toLowerCase()));
+        }
+    }
+
+    @InfixOperator(precedence = OPERATOR_PRECEDENCE_COMPARISON)
+    public static class MatchesOperator extends AbstractOperator {
+        @Override
+        public EvaluationValue evaluate(
+                Expression expression, Token operatorToken, EvaluationValue... operands) {
+            String op1 = operands[0].getStringValue();
+            String op2 = operands[1].getStringValue();
+            Log.i("EXPR " + op1 + " MATCHES " + op2);
+            return expression.convertValue(
+                    !TextUtils.isEmpty(op1) && !TextUtils.isEmpty(op2) &&
+                            Pattern.compile(op2, Pattern.DOTALL).matcher(op1).matches());
+        }
+    }
+
+    static Expression getExpression(EntityRule rule, EntityMessage message) throws JSONException {
+        // https://ezylang.github.io/EvalEx/
+
+        JSONObject jcondition = new JSONObject(rule.condition);
+        if (!jcondition.has("expression"))
+            return null;
+
+        String sender = null;
+        String subject = null;
+        if (message != null) {
+            if (message.from != null && message.from.length == 1)
+                sender = MessageHelper.formatAddresses(message.from);
+            subject = message.subject;
+        }
+
+        ExpressionConfiguration configuration = ExpressionConfiguration.defaultConfiguration();
+        configuration.getOperatorDictionary().addOperator("CONTAINS", new ContainsOperator());
+        configuration.getOperatorDictionary().addOperator("MATCHES", new MatchesOperator());
+
+        return new Expression(jcondition.getString("expression"), configuration)
+                .with("sender", sender)
+                .with("subject", subject);
+    }
+
     boolean execute(Context context, EntityMessage message, String html) throws JSONException, IOException {
         boolean executed = _execute(context, message, html);
         if (this.id != null && executed) {
@@ -655,6 +747,25 @@ public class EntityRule {
     }
 
     void validate(Context context) throws JSONException, IllegalArgumentException {
+        Expression expression = getExpression(this, null);
+        if (expression != null)
+            try {
+                for (String variable : expression.getUsedVariables()) {
+                    Log.i("EXPR variable=" + variable);
+                    if (!EXPR_VARIABLES.contains(variable))
+                        throw new IllegalArgumentException("Unknown variable '" + variable + "'");
+                }
+                Log.i("EXPR validating");
+                expression.validate();
+                Log.i("EXPR validated");
+            } catch (ParseException ex) {
+                Log.w("EXPR", ex);
+                String message = ex.getMessage();
+                if (TextUtils.isEmpty(message))
+                    message = "Invalid expression";
+                throw new IllegalArgumentException(message, ex);
+            }
+
         JSONObject jargs = new JSONObject(action);
         int type = jargs.getInt("type");
 

app/src/main/java/eu/faircode/email/FragmentRule.java

@@ -133,6 +133,8 @@ public class FragmentRule extends FragmentBase {
     private CheckBox cbEveryDay;
     private EditText etYounger;
 
+    private EditText etExpression;
+
     private Spinner spAction;
     private TextView tvActionRemark;
 
@@ -184,6 +186,7 @@ public class FragmentRule extends FragmentBase {
     private ContentLoadingProgressBar pbWait;
 
     private Group grpReady;
+    private Group grpExpression;
     private Group grpAge;
     private Group grpSnooze;
     private Group grpFlag;
@@ -333,6 +336,8 @@ public class FragmentRule extends FragmentBase {
         cbEveryDay = view.findViewById(R.id.cbEveryDay);
         etYounger = view.findViewById(R.id.etYounger);
 
+        etExpression = view.findViewById(R.id.etExpression);
+
         spAction = view.findViewById(R.id.spAction);
         tvActionRemark = view.findViewById(R.id.tvActionRemark);
 
@@ -385,6 +390,7 @@ public class FragmentRule extends FragmentBase {
         pbWait = view.findViewById(R.id.pbWait);
 
         grpReady = view.findViewById(R.id.grpReady);
+        grpExpression = view.findViewById(R.id.grpExpression);
         grpAge = view.findViewById(R.id.grpAge);
         grpSnooze = view.findViewById(R.id.grpSnooze);
         grpFlag = view.findViewById(R.id.grpFlag);
@@ -854,6 +860,7 @@ public class FragmentRule extends FragmentBase {
         tvFolder.setText(null);
         bottom_navigation.setVisibility(View.GONE);
         grpReady.setVisibility(View.GONE);
+        grpExpression.setVisibility(View.GONE);
         grpAge.setVisibility(View.GONE);
         grpSnooze.setVisibility(View.GONE);
         grpFlag.setVisibility(View.GONE);
@@ -1286,6 +1293,8 @@ public class FragmentRule extends FragmentBase {
                         etYounger.setText(jcondition.has("younger")
                                 ? Integer.toString(jcondition.optInt("younger")) : null);
 
+                        etExpression.setText(jcondition.optString("expression"));
+
                         spScheduleDayStart.setSelection(start / (24 * 60));
                         spScheduleDayEnd.setSelection(end / (24 * 60));
 
@@ -1423,6 +1432,7 @@ public class FragmentRule extends FragmentBase {
                     Log.e(ex);
                 } finally {
                     grpReady.setVisibility(View.VISIBLE);
+                    grpExpression.setVisibility(BuildConfig.DEBUG ? View.VISIBLE : View.GONE);
                     grpAge.setVisibility(cbDaily.isChecked() ? View.VISIBLE : View.GONE);
                     if (id < 0)
                         bottom_navigation.getMenu().removeItem(R.id.action_delete);
@@ -1561,7 +1571,9 @@ public class FragmentRule extends FragmentBase {
                             jheader == null &&
                             jbody == null &&
                             jdate == null &&
-                            jschedule == null)
+                            jschedule == null &&
+                            !jcondition.has("younger") &&
+                            !jcondition.has("expression"))
                         throw new IllegalArgumentException(context.getString(R.string.title_rule_condition_missing));
 
                     if (TextUtils.isEmpty(order))
@@ -1729,6 +1741,10 @@ public class FragmentRule extends FragmentBase {
                 Log.e(ex);
             }
 
+        String expression = etExpression.getText().toString().trim();
+        if (!TextUtils.isEmpty(expression))
+            jcondition.put("expression", expression);
+
         return jcondition;
     }
 

app/src/main/res/layout/fragment_rule.xml

@@ -818,6 +818,54 @@
                     app:layout_constraintStart_toStartOf="parent"
                     app:layout_constraintTop_toBottomOf="@id/tvYounger" />
 
+                <TextView
+                    android:id="@+id/tvAndExpression"
+                    android:layout_width="wrap_content"
+                    android:layout_height="wrap_content"
+                    android:layout_marginTop="24dp"
+                    android:text="@string/title_rule_and"
+                    android:textAppearance="@style/TextAppearance.AppCompat.Medium"
+                    android:textColor="?android:attr/textColorPrimary"
+                    app:layout_constraintEnd_toEndOf="parent"
+                    app:layout_constraintStart_toStartOf="parent"
+                    app:layout_constraintTop_toBottomOf="@+id/etYounger" />
+
+                <View
+                    android:id="@+id/vSeparatorExpression"
+                    android:layout_width="match_parent"
+                    android:layout_height="1dp"
+                    android:background="?attr/colorSeparator"
+                    app:layout_constraintStart_toStartOf="parent"
+                    app:layout_constraintTop_toBottomOf="@id/tvAndExpression" />
+
+                <TextView
+                    android:id="@+id/tvExpression"
+                    android:layout_width="0dp"
+                    android:layout_height="wrap_content"
+                    android:layout_marginTop="12dp"
+                    android:text="@string/title_rule_expression"
+                    android:textAppearance="@style/TextAppearance.AppCompat.Small"
+                    app:layout_constraintEnd_toEndOf="parent"
+                    app:layout_constraintStart_toStartOf="parent"
+                    app:layout_constraintTop_toBottomOf="@+id/vSeparatorExpression" />
+
+                <eu.faircode.email.EditTextPlain
+                    android:id="@+id/etExpression"
+                    android:layout_width="0dp"
+                    android:layout_height="wrap_content"
+                    android:hint="@string/title_optional"
+                    android:importantForAutofill="no"
+                    android:textAppearance="@style/TextAppearance.AppCompat.Medium"
+                    app:layout_constraintEnd_toEndOf="parent"
+                    app:layout_constraintStart_toStartOf="parent"
+                    app:layout_constraintTop_toBottomOf="@id/tvExpression" />
+
+                <androidx.constraintlayout.widget.Group
+                    android:id="@+id/grpExpression"
+                    android:layout_width="0dp"
+                    android:layout_height="0dp"
+                    app:constraint_referenced_ids="tvAndExpression,vSeparatorExpression,tvExpression,etExpression" />
+
                 <TextView
                     android:id="@+id/tvAction"
                     android:layout_width="wrap_content"
@@ -828,7 +876,7 @@
                     android:textColor="?android:attr/textColorPrimary"
                     app:layout_constraintEnd_toEndOf="parent"
                     app:layout_constraintStart_toStartOf="parent"
-                    app:layout_constraintTop_toBottomOf="@+id/etYounger" />
+                    app:layout_constraintTop_toBottomOf="@+id/etExpression" />
 
                 <View
                     android:id="@+id/vSeparatorAction"

app/src/main/res/values/strings.xml

@@ -2044,6 +2044,7 @@
     <string name="title_rule_time_rel">Relative time (received) between</string>
     <string name="title_rule_time_every_day">Every day</string>
     <string name="title_rule_younger">Messages younger than (hours)</string>
+    <string name="title_rule_expression" translatable="false">Expression</string>
     <string name="title_rule_regex">Regex</string>
     <string name="title_rule_and">AND</string>
     <string name="title_rule_not">NOT</string>