//===- unittests/BuildSystem/LaneBasedExecutionQueueTest.cpp --------------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See http://swift.org/LICENSE.txt for license information
// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//

#include "llbuild/Basic/FileSystem.h"
#include "llbuild/BuildSystem/BuildExecutionQueue.h"
#include "TempDir.h"

#include "llbuild/BuildSystem/BuildDescription.h"
#include "llbuild/BuildSystem/BuildValue.h"

#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Support/FileSystem.h"

#include "gtest/gtest.h"

#include <atomic>
#include <condition_variable>
#include <ctime>
#include <mutex>

using namespace llbuild;
using namespace llbuild::basic;
using namespace llbuild::buildsystem;

namespace {
  class DummyDelegate : public BuildExecutionQueueDelegate {
  public:
    DummyDelegate() {}

    virtual void commandJobStarted(Command* command) override {}
    virtual void commandJobFinished(Command* command) override {}
    virtual void commandProcessStarted(Command* command,
                                       ProcessHandle handle) override {}
    virtual void commandProcessHadError(Command* command, ProcessHandle handle,
                                        const Twine& message) override {}
    virtual void commandProcessHadOutput(Command* command, ProcessHandle handle,
                                         StringRef data) override {}
    virtual void commandProcessFinished(Command* command, ProcessHandle handle,
                                        CommandResult result,
                                        int exitStatus) override {}
  };

  class DummyCommand : public Command {
  public:
    DummyCommand() : Command("") {}

    virtual void getShortDescription(SmallVectorImpl<char> &result) {}
    virtual void getVerboseDescription(SmallVectorImpl<char> &result) {}
    virtual void configureDescription(const ConfigureContext&,
                                      StringRef description) {};
    virtual void configureInputs(const ConfigureContext&,
                                 const std::vector<Node*>& inputs) {}
    virtual void configureOutputs(const ConfigureContext&,
                                const std::vector<Node*>& outputs) {}
    virtual bool configureAttribute(const ConfigureContext&, StringRef name,
                                    StringRef value) {
      return false;
    }
    virtual bool configureAttribute(const ConfigureContext&, StringRef name,
                                    ArrayRef<StringRef> values) {
      return false;
    }
    virtual bool configureAttribute(
        const ConfigureContext&, StringRef name,
        ArrayRef<std::pair<StringRef, StringRef>> values) {
      return false;
    }
    virtual BuildValue getResultForOutput(Node* node,
                                          const BuildValue& value) {
      return BuildValue::makeInvalid();
    }
    virtual bool isResultValid(BuildSystem& system, const BuildValue& value) {
      return true;
    }
    virtual void start(BuildSystemCommandInterface&, core::Task*) {}
    virtual void providePriorValue(BuildSystemCommandInterface&, core::Task*,
                                   const BuildValue& value) {}
    virtual void provideValue(BuildSystemCommandInterface&, core::Task*,
                              uintptr_t inputID, const BuildValue& value) {}
    virtual BuildValue execute(BuildSystemCommandInterface&, core::Task*,
                               QueueJobContext* context) {
      return BuildValue::makeInvalid();
    }
  };

  TEST(LaneBasedExecutionQueueTest, basic) {
    DummyDelegate delegate;
    std::unique_ptr<FileSystem> fs = createLocalFileSystem();
    TmpDir tempDir{"LaneBasedExecutionQueueTest"};
    std::string outputFile = tempDir.str() + "/yes-output.txt";
    auto queue = std::unique_ptr<BuildExecutionQueue>(
        createLaneBasedExecutionQueue(delegate, 2, /*environment=*/nullptr));

    auto fn = [&outputFile, &queue](QueueJobContext* context) {
      queue->executeShellCommand(context, "yes >" + outputFile);
    };

    DummyCommand dummyCommand;
    queue->addJob(QueueJob(&dummyCommand, fn));

    // Busy wait until `outputFile` appears which indicates that `yes` is
    // running.
    time_t start = ::time(NULL);
    while (fs->getFileInfo(outputFile).isMissing()) {
      if (::time(NULL) > start + 5) {
        // We can't fail gracefully because the `LaneBasedExecutionQueue` will
        // always wait for spawned processes to exit
        abort();
      }
    }

    queue->cancelAllJobs();
    queue.reset();
  }

  TEST(LaneBasedExecutionQueueTest, exhaustsQueueAfterCancellation) {
    DummyDelegate delegate;
    auto queue = std::unique_ptr<BuildExecutionQueue>(
        createLaneBasedExecutionQueue(delegate, 1, /*environment=*/nullptr));

    bool buildStarted { false };
    std::condition_variable buildStartedCondition;
    std::mutex buildStartedMutex;
    std::atomic<int> executions { 0 };

    auto fn = [&buildStarted, &buildStartedCondition, &buildStartedMutex,
               &executions, &queue](QueueJobContext* context) {
      executions++;
      if (queue) { queue->cancelAllJobs(); }

      std::unique_lock<std::mutex> lock(buildStartedMutex);
      buildStarted = true;
      buildStartedCondition.notify_all();
    };

    DummyCommand dummyCommand1;
    queue->addJob(QueueJob(&dummyCommand1, fn));
    DummyCommand dummyCommand2;
    queue->addJob(QueueJob(&dummyCommand2, fn));

    {
      std::unique_lock<std::mutex> lock(buildStartedMutex);
      while (!buildStarted) {
        buildStartedCondition.wait(lock);
      }
    }

    queue.reset();

    // Busy wait until our executions are done, but also have a timeout in case they never finish
    time_t start = ::time(NULL);
    while (executions < 2) {
      if (::time(NULL) > start + 5) {
        break;
      }
    }

    EXPECT_EQ(executions, 2);
  }

}