Add support for different regex parsers

hsregex/build.gradle

@@ -0,0 +1,28 @@
+// SPDX-FileCopyrightText: 2021 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+plugins {
+    id 'java-library'
+}
+
+group 'org.pgpainless'
+
+repositories {
+    mavenCentral()
+    mavenLocal()
+}
+
+dependencies {
+    testImplementation "org.junit.jupiter:junit-jupiter-api:$junitVersion"
+    testRuntimeOnly "org.junit.jupiter:junit-jupiter-engine:$junitVersion"
+
+    implementation(project(":pgpainless-core"))
+
+    // Henry Spencers Regular Expression (RegEx packets)
+    implementation 'com.basistech.tclre:tcl-regex:0.14.5'
+}
+
+test {
+    useJUnitPlatform()
+}

hsregex/src/main/java/org/pgpainless/algorithm/HSRegexInterpreterFactory.java

@@ -0,0 +1,33 @@
+// SPDX-FileCopyrightText: 2022 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package org.pgpainless.algorithm;
+
+import com.basistech.tclre.HsrePattern;
+import com.basistech.tclre.PatternFlags;
+import com.basistech.tclre.RePattern;
+import com.basistech.tclre.RegexException;
+
+public class HSRegexInterpreterFactory extends RegexInterpreterFactory {
+
+    public Regex instantiate(String regex) {
+        return new Regex() {
+
+            private final RePattern pattern;
+
+            {
+                try {
+                    pattern = HsrePattern.compile(regex, PatternFlags.ADVANCED);
+                } catch (RegexException e) {
+                    throw new IllegalArgumentException(e);
+                }
+            }
+
+            @Override
+            public boolean matches(String string) {
+                return pattern.matcher(string).find();
+            }
+        };
+    }
+}

hsregex/src/main/java/org/pgpainless/algorithm/package-info.java

@@ -0,0 +1,10 @@
+// SPDX-FileCopyrightText: 2022 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+/**
+ * Regex interpreter implementation based on Henry Spencers Regular Expression library.
+ *
+ * @see <a href="https://www.rfc-editor.org/rfc/rfc4880#section-8">RFC4880 - §8. Regular Expressions</a>
+ */
+package org.pgpainless.algorithm;

pgpainless-core/build.gradle

@@ -30,4 +30,7 @@ dependencies {
 
     // @Nullable, @Nonnull annotations
     implementation "com.google.code.findbugs:jsr305:3.0.2"
+
+    // HSRE regex for tests
+    testImplementation project(":hsregex")
 }

pgpainless-core/src/main/java/org/pgpainless/algorithm/Regex.java

@@ -0,0 +1,28 @@
+// SPDX-FileCopyrightText: 2022 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package org.pgpainless.algorithm;
+
+import org.pgpainless.key.util.UserId;
+
+public interface Regex {
+
+    /**
+     * Return true, if the regex matches the given user-id.
+     *
+     * @param userId userId
+     * @return true if matches, false otherwise
+     */
+    default boolean matches(UserId userId) {
+        return matches(userId.toString());
+    }
+
+    /**
+     * Return true, if the regex matches the given string.
+     *
+     * @param string string
+     * @return true if matches, false otherwise
+     */
+    boolean matches(String string);
+}

pgpainless-core/src/main/java/org/pgpainless/algorithm/RegexInterpreterFactory.java

@@ -0,0 +1,46 @@
+// SPDX-FileCopyrightText: 2022 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package org.pgpainless.algorithm;
+
+import javax.annotation.Nonnull;
+import java.util.regex.Pattern;
+
+public abstract class RegexInterpreterFactory {
+
+    private static RegexInterpreterFactory INSTANCE;
+
+    public static RegexInterpreterFactory getInstance() {
+        if (INSTANCE == null) {
+            INSTANCE = new JavaRegexInterpreterFactory();
+        }
+        return INSTANCE;
+    }
+
+    public static void setInstance(@Nonnull RegexInterpreterFactory instance) {
+        INSTANCE = instance;
+    }
+
+    public static Regex create(String regex) {
+        return getInstance().instantiate(regex);
+    }
+
+    public abstract Regex instantiate(String regex) throws IllegalArgumentException;
+
+    public static class JavaRegexInterpreterFactory extends RegexInterpreterFactory {
+
+        @Override
+        public Regex instantiate(String regex) {
+            return new Regex() {
+
+                private final Pattern pattern = Pattern.compile(regex);
+
+                @Override
+                public boolean matches(String string) {
+                    return pattern.matcher(string).find();
+                }
+            };
+        }
+    }
+}

pgpainless-core/src/test/java/org/pgpainless/algorithm/RegexTest.java

@@ -0,0 +1,120 @@
+// SPDX-FileCopyrightText: 2022 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package org.pgpainless.algorithm;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.stream.Stream;
+
+import org.junit.jupiter.api.Named;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+import org.pgpainless.key.util.UserId;
+
+public class RegexTest {
+    private static Stream<Arguments> provideRegexInterpreterFactories() {
+        return Stream.of(
+                Arguments.of(Named.of("Default JavaRegexInterpreterFactory",
+                        new RegexInterpreterFactory.JavaRegexInterpreterFactory())),
+                Arguments.of(Named.of("HSRegexInterpreterFactory",
+                        new HSRegexInterpreterFactory()))
+        );
+    }
+
+    @ParameterizedTest
+    @MethodSource("provideRegexInterpreterFactories")
+    public void simpleTest(RegexInterpreterFactory factory) {
+        Regex regex = factory.instantiate("Alice|Bob");
+        assertTrue(regex.matches("Alice"));
+        assertTrue(regex.matches("Bob"));
+        assertFalse(regex.matches("Charlie"));
+    }
+
+    @ParameterizedTest
+    @MethodSource("provideRegexInterpreterFactories")
+    public void testEmailRegexMatchesDomain(RegexInterpreterFactory factory) {
+        Regex regex = factory.instantiate("<[^>]+[@.]pgpainless\\.org>$");
+        assertTrue(regex.matches("Alice <alice@pgpainless.org>"));
+        assertTrue(regex.matches("Bob <bob@pgpainless.org>"));
+        assertFalse(regex.matches("Alice <alice@example.com>"), "wrong domain");
+        assertFalse(regex.matches("Bob <bob@example.com>"), "wrong domain");
+    }
+
+    @ParameterizedTest
+    @MethodSource("provideRegexInterpreterFactories")
+    public void testEmailRegexMatchesOnlyWrappedAddresses(RegexInterpreterFactory factory) {
+        Regex regex = factory.instantiate("<[^>]+[@.]pgpainless\\.org>$");
+        assertTrue(regex.matches("<alice@pgpainless.org>"));
+        assertFalse(regex.matches("alice@pgpainless.org"), "only match mails in <>");
+    }
+
+    @ParameterizedTest
+    @MethodSource("provideRegexInterpreterFactories")
+    public void testCaseSensitivity(RegexInterpreterFactory factory) {
+        Regex regex = factory.instantiate("<[^>]+[@.]pgpainless\\.org>$");
+        assertFalse(regex.matches("Alice <alice@PGPAINLESS.ORG>"));
+    }
+
+    @ParameterizedTest
+    @MethodSource("provideRegexInterpreterFactories")
+    public void testWildCard(RegexInterpreterFactory factory) {
+        Regex regex = factory.instantiate(".*");
+        assertTrue(regex.matches(""));
+        assertTrue(regex.matches("Alice"));
+        assertTrue(regex.matches("<alice@pgpainless.org>"));
+    }
+
+    @ParameterizedTest
+    @MethodSource("provideRegexInterpreterFactories")
+    public void testExclusion(RegexInterpreterFactory factory) {
+        // Test [^>] matches all but '>'
+        Regex regex = factory.instantiate("<[^>]+[@.]pgpainless\\.org>$");
+        assertFalse(regex.matches("<alice>appendix@pgpainless.org>"));
+        assertFalse(regex.matches("<>alice@pgpainless.org>"));
+    }
+
+    @ParameterizedTest
+    @MethodSource("provideRegexInterpreterFactories")
+    public void testOnlyMatchAtTheEnd(RegexInterpreterFactory factory) {
+        Regex regex = factory.instantiate("<[^>]+[@.]pgpainless\\.org>$");
+        assertFalse(regex.matches("Alice <alice@pgpainless.org><bob@example.org>"));
+    }
+
+    @ParameterizedTest
+    @MethodSource("provideRegexInterpreterFactories")
+    public void testRanges(RegexInterpreterFactory factory) {
+        Regex regex = factory.instantiate("<[^>]+[0-9][@.]pgpainless\\.org>$");
+
+        for (int i = 0; i < 10; i++) {
+            String mail = "<user" + i + "@pgpainless.org>";
+            assertTrue(regex.matches(mail));
+        }
+
+        assertFalse(regex.matches("<user@pgpainless.org>"));
+    }
+
+    @ParameterizedTest
+    @MethodSource("provideRegexInterpreterFactories")
+    public void testExactMailMatch(RegexInterpreterFactory factory) {
+        Regex exactMail = factory.instantiate("<exact@pgpainless\\.org>$");
+        assertTrue(exactMail.matches("<exact@pgpainless.org>"));
+        assertTrue(exactMail.matches("Exact Match <exact@pgpainless.org>"));
+        assertFalse(exactMail.matches("<roughly-exact@pgpainless.org>"));
+    }
+
+    @ParameterizedTest
+    @MethodSource("provideRegexInterpreterFactories")
+    public void testSetInstance(RegexInterpreterFactory factory) {
+        RegexInterpreterFactory before = RegexInterpreterFactory.getInstance();
+        RegexInterpreterFactory.setInstance(factory);
+
+        Regex regex = RegexInterpreterFactory.create("<[^>]+[@.]pgpainless\\.org>$");
+        assertTrue(regex.matches(UserId.nameAndEmail("Alice", "alice@pgpainless.org")));
+
+        RegexInterpreterFactory.setInstance(before);
+    }
+}

settings.gradle

@@ -6,5 +6,6 @@ rootProject.name = 'PGPainless'
 
 include 'pgpainless-core',
         'pgpainless-sop',
-        'pgpainless-cli'
+        'pgpainless-cli',
+        'hsregex'