// Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

#include "vm/thread_registry.h"

#include "vm/json_stream.h"
#include "vm/lockers.h"

namespace dart {

ThreadRegistry::~ThreadRegistry() {
  // Go over the free thread list and delete the thread objects.
  {
    MonitorLocker ml(threads_lock());
    // At this point the active list should be empty.
    ASSERT(active_list_ == NULL);

    // Now delete all the threads in the free list.
    while (free_list_ != NULL) {
      Thread* thread = free_list_;
      free_list_ = thread->next_;
      delete thread;
    }
  }
}

Thread* ThreadRegistry::GetFreeThreadLocked(bool is_vm_isolate) {
  ASSERT(threads_lock()->IsOwnedByCurrentThread());
  Thread* thread = GetFromFreelistLocked(is_vm_isolate);
  ASSERT(thread->api_top_scope() == NULL);
  // Now add this Thread to the active list for the isolate.
  AddToActiveListLocked(thread);
  return thread;
}

void ThreadRegistry::ReturnThreadLocked(Thread* thread) {
  ASSERT(threads_lock()->IsOwnedByCurrentThread());
  // Remove thread from the active list for the isolate.
  RemoveFromActiveListLocked(thread);
  ReturnToFreelistLocked(thread);
}

void ThreadRegistry::VisitObjectPointers(Isolate* isolate_of_interest,
                                         ObjectPointerVisitor* visitor,
                                         ValidationPolicy validate_frames) {
  MonitorLocker ml(threads_lock());
  Thread* thread = active_list_;
  while (thread != NULL) {
    if (thread->isolate() == isolate_of_interest) {
      // The mutator thread is visited by the isolate itself (see
      // [Isolate::VisitStackPointers]).
      if (!thread->IsMutatorThread()) {
        thread->VisitObjectPointers(visitor, validate_frames);
      }
    }
    thread = thread->next_;
  }
}

void ThreadRegistry::ReleaseStoreBuffers(Isolate* isolate_of_interest) {
  MonitorLocker ml(threads_lock());
  Thread* thread = active_list_;
  while (thread != NULL) {
    if (thread->isolate() == isolate_of_interest) {
      if (!thread->BypassSafepoints()) {
        thread->ReleaseStoreBuffer();
      }
    }
    thread = thread->next_;
  }
}

void ThreadRegistry::AcquireMarkingStacks(Isolate* isolate_of_interest) {
  MonitorLocker ml(threads_lock());
  Thread* thread = active_list_;
  while (thread != NULL) {
    if (thread->isolate() == isolate_of_interest) {
      if (!thread->BypassSafepoints()) {
        thread->MarkingStackAcquire();
        thread->DeferredMarkingStackAcquire();
      }
    }
    thread = thread->next_;
  }
}

void ThreadRegistry::ReleaseMarkingStacks(Isolate* isolate_of_interest) {
  MonitorLocker ml(threads_lock());
  Thread* thread = active_list_;
  while (thread != NULL) {
    if (thread->isolate() == isolate_of_interest) {
      if (!thread->BypassSafepoints()) {
        thread->MarkingStackRelease();
        thread->DeferredMarkingStackRelease();
      }
    }
    thread = thread->next_;
  }
}

#ifndef PRODUCT
void ThreadRegistry::PrintJSON(JSONStream* stream) const {
  MonitorLocker ml(threads_lock());
  JSONArray threads(stream);
  Thread* current = active_list_;
  while (current != NULL) {
    threads.AddValue(current);
    current = current->next_;
  }
}
#endif

intptr_t ThreadRegistry::CountZoneHandles(Isolate* isolate_of_interest) const {
  MonitorLocker ml(threads_lock());
  intptr_t count = 0;
  Thread* current = active_list_;
  while (current != NULL) {
    if (current->isolate() == isolate_of_interest) {
      count += current->CountZoneHandles();
    }
    current = current->next_;
  }
  return count;
}

intptr_t ThreadRegistry::CountScopedHandles(
    Isolate* isolate_of_interest) const {
  MonitorLocker ml(threads_lock());
  intptr_t count = 0;
  Thread* current = active_list_;
  while (current != NULL) {
    if (current->isolate() == isolate_of_interest) {
      count += current->CountScopedHandles();
    }
    current = current->next_;
  }
  return count;
}

void ThreadRegistry::AddToActiveListLocked(Thread* thread) {
  ASSERT(thread != NULL);
  ASSERT(threads_lock()->IsOwnedByCurrentThread());
  thread->next_ = active_list_;
  active_list_ = thread;
}

void ThreadRegistry::RemoveFromActiveListLocked(Thread* thread) {
  ASSERT(thread != NULL);
  ASSERT(threads_lock()->IsOwnedByCurrentThread());
  Thread* prev = NULL;
  Thread* current = active_list_;
  while (current != NULL) {
    if (current == thread) {
      if (prev == NULL) {
        active_list_ = current->next_;
      } else {
        prev->next_ = current->next_;
      }
      break;
    }
    prev = current;
    current = current->next_;
  }
}

Thread* ThreadRegistry::GetFromFreelistLocked(bool is_vm_isolate) {
  ASSERT(threads_lock()->IsOwnedByCurrentThread());
  Thread* thread = NULL;
  // Get thread structure from free list or create a new one.
  if (free_list_ == NULL) {
    thread = new Thread(is_vm_isolate);
  } else {
    thread = free_list_;
    free_list_ = thread->next_;
  }
  return thread;
}

void ThreadRegistry::ReturnToFreelistLocked(Thread* thread) {
  ASSERT(thread != NULL);
  ASSERT(thread->os_thread() == NULL);
  ASSERT(thread->isolate_ == NULL);
  ASSERT(thread->heap_ == NULL);
  ASSERT(threads_lock()->IsOwnedByCurrentThread());
  // Add thread to the free list.
  thread->next_ = free_list_;
  free_list_ = thread;
}

}  // namespace dart