core/src/main/java/com/google/common/truth/Platform.java

/*
 * Copyright (c) 2014 Google, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.google.common.truth;

import com.google.common.base.Throwables;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.LinkedHashSet;
import java.util.Set;
import java.util.regex.Pattern;
import org.junit.ComparisonFailure;
import org.junit.rules.TestRule;

/**
 * Extracted routines that need to be swapped in for GWT, to allow for minimal deltas between the
 * GWT and non-GWT version.
 *
 * @author Christian Gruber (cgruber@google.com)
 */
final class Platform {
  private Platform() {}

  /** Returns true if the instance is assignable to the type Clazz. */
  static boolean isInstanceOfType(Object instance, Class<?> clazz) {
    return isInstanceOfTypeJava(instance, clazz);
  }

  /**
   * Returns true if the instance is assignable to the type Clazz (suitable for a JVM environment).
   */
  static boolean isInstanceOfTypeJava(Object instance, Class<?> clazz) {
    return clazz.isInstance(instance);
  }

  /**
   * Returns true if the instance is assignable to the type Clazz (suitable for a GWT environment).
   */
  static boolean isInstanceOfTypeGWT(Object instance, Class<?> clazz) {
    String className = clazz.getName();
    Set<String> types = new LinkedHashSet<>();
    types.add(instance.getClass().getCanonicalName());
    addTypeNames(instance.getClass(), types);
    return types.contains(className);
  }

  private static void addInterfaceNames(Class<?>[] interfaces, Set<String> types) {
    for (Class<?> interfaze : interfaces) {
      types.add(interfaze.getName());
      addInterfaceNames(interfaze.getInterfaces(), types);
    }
  }

  private static void addTypeNames(Class<?> clazz, Set<String> types) {
    for (Class<?> current = clazz; current != null; current = current.getSuperclass()) {
      types.add(current.getName());
      addInterfaceNames(current.getInterfaces(), types);
    }
  }

  static AssertionError comparisonFailure(
      String message, String expected, String actual, Throwable cause) {
    return new ComparisonFailureWithCause(message, expected, actual, cause);
  }

  /** Determines if the given subject contains a match for the given regex. */
  static boolean containsMatch(String actual, String regex) {
    return Pattern.compile(regex).matcher(actual).find();
  }

  /**
   * Returns an array containing all of the exceptions that were suppressed to deliver the given
   * exception. If suppressed exceptions are not supported (pre-Java 1.7), an empty array will be
   * returned.
   */
  static Throwable[] getSuppressed(Throwable throwable) {
    try {
      Method getSuppressed = throwable.getClass().getMethod("getSuppressed");
      return (Throwable[]) getSuppressed.invoke(throwable);
    } catch (NoSuchMethodException e) {
      return new Throwable[0];
    } catch (IllegalAccessException e) {
      throw new RuntimeException(e);
    } catch (InvocationTargetException e) {
      throw new RuntimeException(e);
    }
  }

  /**
   * Returns true if stack trace cleaning is explicitly disabled in a system property. This switch
   * os intended to be used when attempting to debug the frameworks which are collapsed or filtered
   * out of stack traces by the cleaner.
   */
  static boolean isStackTraceCleaningDisabled() {
    return Boolean.parseBoolean(
        System.getProperty("com.google.common.truth.disable_stack_trace_cleaning"));
  }

  private static final class ComparisonFailureWithCause extends ComparisonFailure {
    /** Separate cause field, in case initCause() fails. */
    private final Throwable cause;

    ComparisonFailureWithCause(String message, String expected, String actual, Throwable cause) {
      super(message, expected, actual);
      this.cause = cause;

      try {
        initCause(cause);
      } catch (IllegalStateException alreadyInitializedBecauseOfHarmonyBug) {
        // See Truth.AssertionErrorWithCause.
      }
    }

    @Override
    @SuppressWarnings("UnsynchronizedOverridesSynchronized")
    public Throwable getCause() {
      return cause;
    }

    @Override
    public String toString() {
      return getLocalizedMessage();
    }
  }

  static String doubleToString(double value) {
    return Double.toString(value);
  }

  static String floatToString(float value) {
    return Float.toString(value);
  }

  /** Returns a human readable string representation of the throwable's stack trace. */
  static String getStackTraceAsString(Throwable throwable) {
    return Throwables.getStackTraceAsString(throwable);
  }

  /** Tests if current platform is Android. */
  static boolean isAndroid() {
    return System.getProperties().getProperty("java.runtime.name").contains("Android");
  }

  /**
   * Wrapping interface of {@link TestRule} to be used within truth.
   *
   * <p>Note that the sole purpose of this interface is to allow it to be swapped in GWT
   * implementation.
   */
  interface JUnitTestRule extends TestRule {}
}