/*
 * Copyright 2014 The Error Prone Authors.
 *
 * 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.errorprone.bugpatterns.threadsafety;

import static com.google.errorprone.BugPattern.SeverityLevel.ERROR;

import com.google.errorprone.BugPattern;
import com.google.errorprone.CompilationTestHelper;
import com.google.errorprone.VisitorState;
import com.google.errorprone.matchers.Description;
import com.sun.source.tree.Tree;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;

/** {@link GuardedByLockSetAnalyzer}Test */
@RunWith(JUnit4.class)
public class HeldLockAnalyzerTest {
  private final CompilationTestHelper compilationHelper =
      CompilationTestHelper.newInstance(GuardedByLockSetAnalyzer.class, getClass());

  @Test
  public void instance() {
    compilationHelper
        .addSourceLines(
            "threadsafety/Test.java",
            "package threadsafety;",
            "import javax.annotation.concurrent.GuardedBy;",
            "import java.util.concurrent.locks.Lock;",
            "class Test {",
            "  final Lock lock = null;",
            "  @GuardedBy(\"lock\")",
            "  int x;",
            "  void m() {",
            "    lock.lock();",
            "    try {",
            "      // BUG: Diagnostic contains:",
            "      // [(SELECT (THIS) lock)]",
            "      x++;",
            "    } finally { lock.unlock(); }",
            "  }",
            "}")
        .doTest();
  }

  @Test
  public void twoInstances() {
    compilationHelper
        .addSourceLines(
            "threadsafety/Test.java",
            "package threadsafety;",
            "import javax.annotation.concurrent.GuardedBy;",
            "import java.util.concurrent.locks.Lock;",
            "class Test {",
            "  final Lock lock = null;",
            "  @GuardedBy(\"lock\")",
            "  int x;",
            "  void m(Lock lock2) {",
            "    lock.lock();",
            "    lock2.lock();",
            "    try {",
            "    // BUG: Diagnostic contains:",
            "    // [(LOCAL_VARIABLE lock2), (SELECT (THIS) lock)]",
            "    x++;",
            "    } finally { lock.unlock(); lock2.unlock(); }",
            "  }",
            "}")
        .doTest();
  }

  @Test
  public void synchronizedMethod() {
    compilationHelper
        .addSourceLines(
            "threadsafety/Test.java",
            "package threadsafety;",
            "import javax.annotation.concurrent.GuardedBy;",
            "import java.util.concurrent.locks.Lock;",
            "class Test {",
            "  @GuardedBy(\"this\")",
            "  int x;",
            "  synchronized void m() {",
            "    // BUG: Diagnostic contains:  [(THIS)]",
            "    x++;",
            "  }",
            "}")
        .doTest();
  }

  @Test
  public void synchronizedThis() {
    compilationHelper
        .addSourceLines(
            "threadsafety/Test.java",
            "package threadsafety;",
            "import javax.annotation.concurrent.GuardedBy;",
            "import java.util.concurrent.locks.Lock;",
            "class Test {",
            "  @GuardedBy(\"this\")",
            "  int x;",
            "  void m() {",
            "    synchronized (this) {",
            "      // BUG: Diagnostic contains:  [(THIS)]",
            "      x++;",
            "    }",
            "  }",
            "}")
        .doTest();
  }

  @Test
  public void synchronizedField() {
    compilationHelper
        .addSourceLines(
            "threadsafety/Test.java",
            "package threadsafety;",
            "import javax.annotation.concurrent.GuardedBy;",
            "class Lock { final Object lock = null; }",
            "class Test {",
            "  final Lock mu = new Lock();",
            "  @GuardedBy(\"this\")",
            "  int x;",
            "  void m() {",
            "    synchronized (mu.lock) {",
            "      // BUG: Diagnostic contains:",
            "      // [(SELECT (SELECT (THIS) mu) lock)]",
            "      x++;",
            "    }",
            "  }",
            "}")
        .doTest();
  }

  @Test
  public void synchronizedClass() {
    compilationHelper
        .addSourceLines(
            "threadsafety/Test.java",
            "package threadsafety;",
            "import javax.annotation.concurrent.GuardedBy;",
            "class Lock {}",
            "class Test {",
            "  final Lock mu = new Lock();",
            "  @GuardedBy(\"this\")",
            "  int x;",
            "  void m() {",
            "    synchronized (Lock.class) {",
            "      // BUG: Diagnostic contains:  [(CLASS_LITERAL threadsafety.Lock)]",
            "      x++;",
            "    }",
            "  }",
            "}")
        .doTest();
  }

  @Test
  public void locked() {
    compilationHelper
        .addSourceLines(
            "threadsafety/Test.java",
            "package threadsafety;",
            "import javax.annotation.concurrent.GuardedBy;",
            "import java.util.concurrent.locks.Lock;",
            "class Test {",
            "  final Lock mu = null;",
            "  final Lock lock = null;",
            "  @GuardedBy(\"lock\")",
            "  int x;",
            "  void m() {",
            "    mu.lock();",
            "    // BUG: Diagnostic contains:  []",
            "    x++;",
            "    try {",
            "      // BUG: Diagnostic contains:",
            "      // [(SELECT (THIS) mu)]",
            "      x++;",
            "    } finally {",
            "      mu.unlock();",
            "    }",
            "    // BUG: Diagnostic contains:  []",
            "    x++;",
            "  }",
            "}")
        .doTest();
  }

  /** A customized {@link GuardedByChecker} that prints more test-friendly diagnostics. */
  @BugPattern(name = "GuardedByLockSet", summary = "", explanation = "", severity = ERROR)
  public static class GuardedByLockSetAnalyzer extends GuardedByChecker {
    @Override
    protected Description checkGuardedAccess(
        Tree tree, GuardedByExpression guard, HeldLockSet live, VisitorState state) {
      List<String> toSort = new ArrayList<>();
      for (GuardedByExpression node : live.allLocks()) {
        toSort.add(node.debugPrint());
      }
      Collections.sort(toSort);
      return buildDescription(tree).setMessage("Holding: " + toSort).build();
    }
  }
}
