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      1 // Copyright 2013 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #include "mojo/common/bindings_support_impl.h"
      6 
      7 #include "base/atomic_ref_count.h"
      8 #include "base/bind.h"
      9 #include "base/lazy_instance.h"
     10 #include "base/threading/thread_local.h"
     11 #include "mojo/common/handle_watcher.h"
     12 
     13 namespace mojo {
     14 namespace common {
     15 namespace {
     16 base::LazyInstance<base::ThreadLocalPointer<Buffer> >::Leaky lazy_tls_ptr =
     17     LAZY_INSTANCE_INITIALIZER;
     18 }
     19 
     20 // Context is used to track the number of HandleWatcher objects in use by a
     21 // particular BindingsSupportImpl instance.
     22 class BindingsSupportImpl::Context
     23     : public base::RefCountedThreadSafe<BindingsSupportImpl::Context> {
     24  public:
     25   void CallOnHandleReady(HandleWatcher* watcher,
     26                          AsyncWaitCallback* callback,
     27                          MojoResult result) {
     28     delete watcher;
     29     callback->OnHandleReady(result);
     30   }
     31 
     32  private:
     33   friend class base::RefCountedThreadSafe<Context>;
     34   virtual ~Context() {}
     35 };
     36 
     37 BindingsSupportImpl::BindingsSupportImpl()
     38     : context_(new Context()) {
     39 }
     40 
     41 BindingsSupportImpl::~BindingsSupportImpl() {
     42   // All HandleWatcher instances created through this interface should have
     43   // been destroyed.
     44   DCHECK(context_->HasOneRef());
     45 }
     46 
     47 Buffer* BindingsSupportImpl::GetCurrentBuffer() {
     48   return lazy_tls_ptr.Pointer()->Get();
     49 }
     50 
     51 Buffer* BindingsSupportImpl::SetCurrentBuffer(Buffer* buf) {
     52   Buffer* old_buf = lazy_tls_ptr.Pointer()->Get();
     53   lazy_tls_ptr.Pointer()->Set(buf);
     54   return old_buf;
     55 }
     56 
     57 BindingsSupport::AsyncWaitID BindingsSupportImpl::AsyncWait(
     58     const Handle& handle,
     59     MojoWaitFlags flags,
     60     AsyncWaitCallback* callback) {
     61   // This instance will be deleted when done or cancelled.
     62   HandleWatcher* watcher = new HandleWatcher();
     63 
     64   watcher->Start(handle,
     65                  flags,
     66                  MOJO_DEADLINE_INDEFINITE,
     67                  base::Bind(&Context::CallOnHandleReady,
     68                             context_,
     69                             watcher,
     70                             callback));
     71   return watcher;
     72 }
     73 
     74 void BindingsSupportImpl::CancelWait(AsyncWaitID async_wait_id) {
     75   HandleWatcher* watcher = static_cast<HandleWatcher*>(async_wait_id);
     76   delete watcher;
     77 }
     78 
     79 }  // namespace common
     80 }  // namespace mojo
     81