Revert "Reland [clang] DirectoryWatcher"

This reverts commit fdcb7f47e783933e0af8a5fae91132269a208268.

llvm-svn: 365948

1 files changed, 0 insertions, 345 deletions

diff --git a/clang/lib/DirectoryWatcher/linux/DirectoryWatcher-linux.cpp b/clang/lib/DirectoryWatcher/linux/DirectoryWatcher-linux.cpp
deleted file mode 100644
index 986ebc5d95f..00000000000
--- a/clang/lib/DirectoryWatcher/linux/DirectoryWatcher-linux.cpp
+++ /dev/null
@@ -1,345 +0,0 @@
-//===- DirectoryWatcher-linux.cpp - Linux-platform directory watching -----===//
-//
-// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
-// See https://llvm.org/LICENSE.txt for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-//===----------------------------------------------------------------------===//
-
-#include "DirectoryScanner.h"
-#include "clang/DirectoryWatcher/DirectoryWatcher.h"
-
-#include "llvm/ADT/STLExtras.h"
-#include "llvm/ADT/ScopeExit.h"
-#include "llvm/Support/AlignOf.h"
-#include "llvm/Support/Errno.h"
-#include "llvm/Support/Mutex.h"
-#include "llvm/Support/Path.h"
-#include <atomic>
-#include <condition_variable>
-#include <mutex>
-#include <queue>
-#include <string>
-#include <thread>
-#include <vector>
-
-#include <fcntl.h>
-#include <sys/epoll.h>
-#include <sys/inotify.h>
-#include <unistd.h>
-
-namespace {
-
-using namespace llvm;
-using namespace clang;
-
-/// Pipe for inter-thread synchronization - for epoll-ing on multiple
-/// conditions. It is meant for uni-directional 1:1 signalling - specifically:
-/// no multiple consumers, no data passing. Thread waiting for signal should
-/// poll the FDRead. Signalling thread should call signal() which writes single
-/// character to FDRead.
-struct SemaphorePipe {
-  // Expects two file-descriptors opened as a pipe in the canonical POSIX
-  // order: pipefd[0] refers to the read end of the pipe. pipefd[1] refers to
-  // the write end of the pipe.
-  SemaphorePipe(int pipefd[2])
-      : FDRead(pipefd[0]), FDWrite(pipefd[1]), OwnsFDs(true) {}
-  SemaphorePipe(const SemaphorePipe &) = delete;
-  void operator=(const SemaphorePipe &) = delete;
-  SemaphorePipe(SemaphorePipe &&other)
-      : FDRead(other.FDRead), FDWrite(other.FDWrite),
-        OwnsFDs(other.OwnsFDs) // Someone could have moved from the other
-                               // instance before.
-  {
-    other.OwnsFDs = false;
-  };
-
-  void signal() {
-    ssize_t Result = llvm::sys::RetryAfterSignal(-1, write, FDWrite, "A", 1);
-    assert(Result != -1);
-  }
-  ~SemaphorePipe() {
-    if (OwnsFDs) {
-      close(FDWrite);
-      close(FDRead);
-    }
-  }
-  const int FDRead;
-  const int FDWrite;
-  bool OwnsFDs;
-
-  static llvm::Optional<SemaphorePipe> create() {
-    int InotifyPollingStopperFDs[2];
-    if (pipe2(InotifyPollingStopperFDs, O_CLOEXEC) == -1)
-      return llvm::None;
-    return SemaphorePipe(InotifyPollingStopperFDs);
-  }
-};
-
-/// Mutex-protected queue of Events.
-class EventQueue {
-  std::mutex Mtx;
-  std::condition_variable NonEmpty;
-  std::queue<DirectoryWatcher::Event> Events;
-
-public:
-  void push_back(const DirectoryWatcher::Event::EventKind K,
-                 StringRef Filename) {
-    {
-      std::unique_lock<std::mutex> L(Mtx);
-      Events.emplace(K, Filename);
-    }
-    NonEmpty.notify_one();
-  }
-
-  // Blocks on caller thread and uses codition_variable to wait until there's an
-  // event to return.
-  DirectoryWatcher::Event pop_front_blocking() {
-    std::unique_lock<std::mutex> L(Mtx);
-    while (true) {
-      // Since we might have missed all the prior notifications on NonEmpty we
-      // have to check the queue first (under lock).
-      if (!Events.empty()) {
-        DirectoryWatcher::Event Front = Events.front();
-        Events.pop();
-        return Front;
-      }
-      NonEmpty.wait(L, [this]() { return !Events.empty(); });
-    }
-  }
-};
-
-class DirectoryWatcherLinux : public clang::DirectoryWatcher {
-public:
-  DirectoryWatcherLinux(
-      llvm::StringRef WatchedDirPath,
-      std::function<void(llvm::ArrayRef<Event>, bool)> Receiver,
-      bool WaitForInitialSync, int InotifyFD, int InotifyWD,
-      SemaphorePipe &&InotifyPollingStopSignal);
-
-  ~DirectoryWatcherLinux() override {
-    StopWork();
-    InotifyPollingThread.join();
-    EventsReceivingThread.join();
-    inotify_rm_watch(InotifyFD, InotifyWD);
-    llvm::sys::RetryAfterSignal(-1, close, InotifyFD);
-  }
-
-private:
-  const std::string WatchedDirPath;
-  // inotify file descriptor
-  int InotifyFD = -1;
-  // inotify watch descriptor
-  int InotifyWD = -1;
-
-  EventQueue Queue;
-
-  // Make sure lifetime of Receiver fully contains lifetime of
-  // EventsReceivingThread.
-  std::function<void(llvm::ArrayRef<Event>, bool)> Receiver;
-
-  // Consumes inotify events and pushes directory watcher events to the Queue.
-  void InotifyPollingLoop();
-  std::thread InotifyPollingThread;
-  // Using pipe so we can epoll two file descriptors at once - inotify and
-  // stopping condition.
-  SemaphorePipe InotifyPollingStopSignal;
-
-  // Does the initial scan of the directory - directly calling Receiver,
-  // bypassing the Queue. Both InitialScan and EventReceivingLoop use Receiver
-  // which isn't necessarily thread-safe.
-  void InitialScan();
-
-  // Processing events from the Queue.
-  // In case client doesn't want to do the initial scan synchronously
-  // (WaitForInitialSync=false in ctor) we do the initial scan at the beginning
-  // of this thread.
-  std::thread EventsReceivingThread;
-  // Push event of WatcherGotInvalidated kind to the Queue to stop the loop.
-  // Both InitialScan and EventReceivingLoop use Receiver which isn't
-  // necessarily thread-safe.
-  void EventReceivingLoop();
-
-  // Stops all the async work. Reentrant.
-  void StopWork() {
-    Queue.push_back(DirectoryWatcher::Event::EventKind::WatcherGotInvalidated,
-                    "");
-    InotifyPollingStopSignal.signal();
-  }
-};
-
-void DirectoryWatcherLinux::InotifyPollingLoop() {
-  // We want to be able to read ~30 events at once even in the worst case
-  // (obscenely long filenames).
-  constexpr size_t EventBufferLength =
-      30 * (sizeof(struct inotify_event) + NAME_MAX + 1);
-  // http://man7.org/linux/man-pages/man7/inotify.7.html
-  // Some systems cannot read integer variables if they are not
-  // properly aligned. On other systems, incorrect alignment may
-  // decrease performance. Hence, the buffer used for reading from
-  // the inotify file descriptor should have the same alignment as
-  // struct inotify_event.
-
-  auto ManagedBuffer =
-      llvm::make_unique<llvm::AlignedCharArray<alignof(struct inotify_event),
-                                               EventBufferLength>>();
-  char *const Buf = ManagedBuffer->buffer;
-
-  const int EpollFD = epoll_create1(EPOLL_CLOEXEC);
-  if (EpollFD == -1) {
-    StopWork();
-    return;
-  }
-  auto EpollFDGuard = llvm::make_scope_exit([EpollFD]() { close(EpollFD); });
-
-  struct epoll_event EventSpec;
-  EventSpec.events = EPOLLIN;
-  EventSpec.data.fd = InotifyFD;
-  if (epoll_ctl(EpollFD, EPOLL_CTL_ADD, InotifyFD, &EventSpec) == -1) {
-    StopWork();
-    return;
-  }
-
-  EventSpec.data.fd = InotifyPollingStopSignal.FDRead;
-  if (epoll_ctl(EpollFD, EPOLL_CTL_ADD, InotifyPollingStopSignal.FDRead,
-                &EventSpec) == -1) {
-    StopWork();
-    return;
-  }
-
-  std::array<struct epoll_event, 2> EpollEventBuffer;
-
-  while (true) {
-    const int EpollWaitResult = llvm::sys::RetryAfterSignal(
-        -1, epoll_wait, EpollFD, EpollEventBuffer.data(),
-        EpollEventBuffer.size(), /*timeout=*/-1 /*== infinity*/);
-    if (EpollWaitResult == -1) {
-      StopWork();
-      return;
-    }
-
-    // Multiple epoll_events can be received for a single file descriptor per
-    // epoll_wait call.
-    for (const auto &EpollEvent : EpollEventBuffer) {
-      if (EpollEvent.data.fd == InotifyPollingStopSignal.FDRead) {
-        StopWork();
-        return;
-      }
-    }
-
-    // epoll_wait() always return either error or >0 events. Since there was no
-    // event for stopping, it must be an inotify event ready for reading.
-    ssize_t NumRead = llvm::sys::RetryAfterSignal(-1, read, InotifyFD, Buf,
-                                                  EventBufferLength);
-    for (char *P = Buf; P < Buf + NumRead;) {
-      if (P + sizeof(struct inotify_event) > Buf + NumRead) {
-        StopWork();
-        llvm_unreachable("an incomplete inotify_event was read");
-        return;
-      }
-
-      struct inotify_event *Event = reinterpret_cast<struct inotify_event *>(P);
-      P += sizeof(struct inotify_event) + Event->len;
-
-      if (Event->mask & (IN_CREATE | IN_MODIFY | IN_MOVED_TO | IN_DELETE) &&
-          Event->len <= 0) {
-        StopWork();
-        llvm_unreachable("expected a filename from inotify");
-        return;
-      }
-
-      if (Event->mask & (IN_CREATE | IN_MOVED_TO | IN_MODIFY)) {
-        Queue.push_back(DirectoryWatcher::Event::EventKind::Modified,
-                        Event->name);
-      } else if (Event->mask & (IN_DELETE | IN_MOVED_FROM)) {
-        Queue.push_back(DirectoryWatcher::Event::EventKind::Removed,
-                        Event->name);
-      } else if (Event->mask & (IN_DELETE_SELF | IN_MOVE_SELF)) {
-        Queue.push_back(DirectoryWatcher::Event::EventKind::WatchedDirRemoved,
-                        "");
-        StopWork();
-        return;
-      } else if (Event->mask & IN_IGNORED) {
-        StopWork();
-        return;
-      } else {
-        StopWork();
-        llvm_unreachable("Unknown event type.");
-        return;
-      }
-    }
-  }
-}
-
-void DirectoryWatcherLinux::InitialScan() {
-  this->Receiver(getAsFileEvents(scanDirectory(WatchedDirPath)),
-                 /*IsInitial=*/true);
-}
-
-void DirectoryWatcherLinux::EventReceivingLoop() {
-  while (true) {
-    DirectoryWatcher::Event Event = this->Queue.pop_front_blocking();
-    this->Receiver(Event, false);
-    if (Event.Kind ==
-        DirectoryWatcher::Event::EventKind::WatcherGotInvalidated) {
-      StopWork();
-      return;
-    }
-  }
-}
-
-DirectoryWatcherLinux::DirectoryWatcherLinux(
-    StringRef WatchedDirPath,
-    std::function<void(llvm::ArrayRef<Event>, bool)> Receiver,
-    bool WaitForInitialSync, int InotifyFD, int InotifyWD,
-    SemaphorePipe &&InotifyPollingStopSignal)
-    : WatchedDirPath(WatchedDirPath), InotifyFD(InotifyFD),
-      InotifyWD(InotifyWD), Receiver(Receiver),
-      InotifyPollingStopSignal(std::move(InotifyPollingStopSignal)) {
-
-  InotifyPollingThread = std::thread([this]() { InotifyPollingLoop(); });
-  // We have no guarantees about thread safety of the Receiver which is being
-  // used in both InitialScan and EventReceivingLoop. We shouldn't run these
-  // only synchronously.
-  if (WaitForInitialSync) {
-    InitialScan();
-    EventsReceivingThread = std::thread([this]() { EventReceivingLoop(); });
-  } else {
-    EventsReceivingThread = std::thread([this]() {
-      // FIXME: We might want to terminate an async initial scan early in case
-      // of a failure in EventsReceivingThread.
-      InitialScan();
-      EventReceivingLoop();
-    });
-  }
-}
-
-} // namespace
-
-std::unique_ptr<DirectoryWatcher> clang::DirectoryWatcher::create(
-    StringRef Path,
-    std::function<void(llvm::ArrayRef<DirectoryWatcher::Event>, bool)> Receiver,
-    bool WaitForInitialSync) {
-  if (Path.empty())
-    return nullptr;
-
-  const int InotifyFD = inotify_init1(IN_CLOEXEC);
-  if (InotifyFD == -1)
-    return nullptr;
-
-  const int InotifyWD = inotify_add_watch(
-      InotifyFD, Path.str().c_str(),
-      IN_CREATE | IN_DELETE | IN_DELETE_SELF | IN_EXCL_UNLINK | IN_MODIFY |
-          IN_MOVED_FROM | IN_MOVE_SELF | IN_MOVED_TO | IN_ONLYDIR | IN_IGNORED);
-  if (InotifyWD == -1)
-    return nullptr;
-
-  auto InotifyPollingStopper = SemaphorePipe::create();
-
-  if (!InotifyPollingStopper)
-    return nullptr;
-
-  return llvm::make_unique<DirectoryWatcherLinux>(
-      Path, Receiver, WaitForInitialSync, InotifyFD, InotifyWD,
-      std::move(*InotifyPollingStopper));
-}
\ No newline at end of file