Add a Mojo EDK for Chrome that uses one OS pipe per message pipe.

mojo/edk/system/core.cc

Index: mojo/edk/system/core.cc
diff --git a/third_party/mojo/src/mojo/edk/system/core.cc b/mojo/edk/system/core.cc
similarity index 71%
copy from third_party/mojo/src/mojo/edk/system/core.cc
copy to mojo/edk/system/core.cc
index c2b01361ce7c3b1833531fe5f5c28ac48858cacb..06f5b4a7dd6c1aa001fad1d36fe4e5a07608f51a 100644
--- a/third_party/mojo/src/mojo/edk/system/core.cc
+++ b/mojo/edk/system/core.cc
@@ -2,31 +2,30 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "third_party/mojo/src/mojo/edk/system/core.h"
+#include "mojo/edk/system/core.h"
 
 #include <vector>
 
 #include "base/logging.h"
 #include "base/time/time.h"
+#include "mojo/edk/embedder/platform_channel_pair.h"
+#include "mojo/edk/embedder/platform_shared_buffer.h"
+#include "mojo/edk/embedder/platform_support.h"
+#include "mojo/edk/system/async_waiter.h"
+#include "mojo/edk/system/configuration.h"
+#include "mojo/edk/system/data_pipe.h"
+#include "mojo/edk/system/data_pipe_consumer_dispatcher.h"
+#include "mojo/edk/system/data_pipe_producer_dispatcher.h"
+#include "mojo/edk/system/dispatcher.h"
+#include "mojo/edk/system/handle_signals_state.h"
+#include "mojo/edk/system/message_pipe_dispatcher.h"
+#include "mojo/edk/system/shared_buffer_dispatcher.h"
+#include "mojo/edk/system/waiter.h"
 #include "mojo/public/c/system/macros.h"
 #include "mojo/public/cpp/system/macros.h"
-#include "third_party/mojo/src/mojo/edk/embedder/platform_shared_buffer.h"
-#include "third_party/mojo/src/mojo/edk/embedder/platform_support.h"
-#include "third_party/mojo/src/mojo/edk/system/async_waiter.h"
-#include "third_party/mojo/src/mojo/edk/system/configuration.h"
-#include "third_party/mojo/src/mojo/edk/system/data_pipe.h"
-#include "third_party/mojo/src/mojo/edk/system/data_pipe_consumer_dispatcher.h"
-#include "third_party/mojo/src/mojo/edk/system/data_pipe_producer_dispatcher.h"
-#include "third_party/mojo/src/mojo/edk/system/dispatcher.h"
-#include "third_party/mojo/src/mojo/edk/system/handle_signals_state.h"
-#include "third_party/mojo/src/mojo/edk/system/memory.h"
-#include "third_party/mojo/src/mojo/edk/system/message_pipe.h"
-#include "third_party/mojo/src/mojo/edk/system/message_pipe_dispatcher.h"
-#include "third_party/mojo/src/mojo/edk/system/shared_buffer_dispatcher.h"
-#include "third_party/mojo/src/mojo/edk/system/waiter.h"
 
 namespace mojo {
-namespace system {
+namespace edk {
 
 // Implementation notes
 //
@@ -78,7 +77,7 @@ namespace system {
 //      held.
 
 // TODO(vtl): This should take a |scoped_ptr<PlatformSupport>| as a parameter.
-Core::Core(embedder::PlatformSupport* platform_support)
+Core::Core(PlatformSupport* platform_support)
     : platform_support_(platform_support) {
 }
 
@@ -86,7 +85,7 @@ Core::~Core() {
 }
 
 MojoHandle Core::AddDispatcher(const scoped_refptr<Dispatcher>& dispatcher) {
-  MutexLocker locker(&handle_table_mutex_);
+  base::AutoLock locker(handle_table_lock_);
   return handle_table_.AddDispatcher(dispatcher);
 }
 
@@ -94,7 +93,7 @@ scoped_refptr<Dispatcher> Core::GetDispatcher(MojoHandle handle) {
   if (handle == MOJO_HANDLE_INVALID)
     return nullptr;
 
-  MutexLocker locker(&handle_table_mutex_);
+  base::AutoLock locker(handle_table_lock_);
   return handle_table_.GetDispatcher(handle);
 }
 
@@ -103,7 +102,7 @@ MojoResult Core::GetAndRemoveDispatcher(MojoHandle handle,
   if (handle == MOJO_HANDLE_INVALID)
     return MOJO_RESULT_INVALID_ARGUMENT;
 
-  MutexLocker locker(&handle_table_mutex_);
+  base::AutoLock locker(handle_table_lock_);
   return handle_table_.GetAndRemoveDispatcher(handle, dispatcher);
 }
 
@@ -130,7 +129,7 @@ MojoResult Core::Close(MojoHandle handle) {
 
   scoped_refptr<Dispatcher> dispatcher;
   {
-    MutexLocker locker(&handle_table_mutex_);
+    base::AutoLock locker(handle_table_lock_);
     MojoResult result =
         handle_table_.GetAndRemoveDispatcher(handle, &dispatcher);
     if (result != MOJO_RESULT_OK)
@@ -138,7 +137,7 @@ MojoResult Core::Close(MojoHandle handle) {
   }
 
   // The dispatcher doesn't have a say in being closed, but gets notified of it.
-  // Note: This is done outside of |handle_table_mutex_|. As a result, there's a
+  // Note: This is done outside of |handle_table_lock_|. As a result, there's a
   // race condition that the dispatcher must handle; see the comment in
   // |Dispatcher| in dispatcher.h.
   return dispatcher->Close();
@@ -147,57 +146,49 @@ MojoResult Core::Close(MojoHandle handle) {
 MojoResult Core::Wait(MojoHandle handle,
                       MojoHandleSignals signals,
                       MojoDeadline deadline,
-                      UserPointer<MojoHandleSignalsState> signals_state) {
+                      MojoHandleSignalsState* signals_state) {
   uint32_t unused = static_cast<uint32_t>(-1);
   HandleSignalsState hss;
   MojoResult rv = WaitManyInternal(&handle, &signals, 1, deadline, &unused,
-                                   signals_state.IsNull() ? nullptr : &hss);
-  if (rv != MOJO_RESULT_INVALID_ARGUMENT && !signals_state.IsNull())
-    signals_state.Put(hss);
+                                   signals_state ? &hss : nullptr);
+  if (rv != MOJO_RESULT_INVALID_ARGUMENT && signals_state)
+    *signals_state = hss;
   return rv;
 }
 
-MojoResult Core::WaitMany(UserPointer<const MojoHandle> handles,
-                          UserPointer<const MojoHandleSignals> signals,
+MojoResult Core::WaitMany(const MojoHandle* handles,
+                          const MojoHandleSignals* signals,
                           uint32_t num_handles,
                           MojoDeadline deadline,
-                          UserPointer<uint32_t> result_index,
-                          UserPointer<MojoHandleSignalsState> signals_states) {
+                          uint32_t* result_index,
+                          MojoHandleSignalsState* signals_state) {
   if (num_handles < 1)
     return MOJO_RESULT_INVALID_ARGUMENT;
   if (num_handles > GetConfiguration().max_wait_many_num_handles)
     return MOJO_RESULT_RESOURCE_EXHAUSTED;
 
-  UserPointer<const MojoHandle>::Reader handles_reader(handles, num_handles);
-  UserPointer<const MojoHandleSignals>::Reader signals_reader(signals,
-                                                              num_handles);
-  uint32_t index = static_cast<uint32_t>(-1);
+  uint32_t index = static_cast<uint32_t>(-1);
   MojoResult rv;
-  if (signals_states.IsNull()) {
-    rv = WaitManyInternal(handles_reader.GetPointer(),
-                          signals_reader.GetPointer(), num_handles, deadline,
-                          &index, nullptr);
-  } else {
-    UserPointer<MojoHandleSignalsState>::Writer signals_states_writer(
-        signals_states, num_handles);
-    // Note: The |reinterpret_cast| is safe, since |HandleSignalsState| is a
+  if (!signals_state) {
+    rv = WaitManyInternal(handles, signals, num_handles, deadline, &index,
+                          nullptr);
+  } else {
+    // Note: The |reinterpret_cast| is safe, since |HandleSignalsState| is a
     // subclass of |MojoHandleSignalsState| that doesn't add any data members.
-    rv = WaitManyInternal(handles_reader.GetPointer(),
-                          signals_reader.GetPointer(), num_handles, deadline,
-                          &index, reinterpret_cast<HandleSignalsState*>(
-                                      signals_states_writer.GetPointer()));
-    if (rv != MOJO_RESULT_INVALID_ARGUMENT)
-      signals_states_writer.Commit();
-  }
-  if (index != static_cast<uint32_t>(-1) && !result_index.IsNull())
-    result_index.Put(index);
+    rv = WaitManyInternal(handles, signals, num_handles, deadline, &index,
+                          reinterpret_cast<HandleSignalsState*>(signals_state));
+  }
+  if (index != static_cast<uint32_t>(-1) && result_index)
+    *result_index = index;
   return rv;
 }
 
 MojoResult Core::CreateMessagePipe(
-    UserPointer<const MojoCreateMessagePipeOptions> options,
-    UserPointer<MojoHandle> message_pipe_handle0,
-    UserPointer<MojoHandle> message_pipe_handle1) {
+    const MojoCreateMessagePipeOptions* options,
+    MojoHandle* message_pipe_handle0,
+    MojoHandle* message_pipe_handle1) {
+  CHECK(message_pipe_handle0);
+  CHECK(message_pipe_handle1);
   MojoCreateMessagePipeOptions validated_options = {};
   MojoResult result =
       MessagePipeDispatcher::ValidateCreateOptions(options, &validated_options);
@@ -211,7 +202,7 @@ MojoResult Core::CreateMessagePipe(
 
   std::pair<MojoHandle, MojoHandle> handle_pair;
   {
-    MutexLocker locker(&handle_table_mutex_);
+    base::AutoLock locker(handle_table_lock_);
     handle_pair = handle_table_.AddDispatcherPair(dispatcher0, dispatcher1);
   }
   if (handle_pair.first == MOJO_HANDLE_INVALID) {
@@ -222,12 +213,12 @@ MojoResult Core::CreateMessagePipe(
     return MOJO_RESULT_RESOURCE_EXHAUSTED;
   }
 
-  scoped_refptr<MessagePipe> message_pipe(MessagePipe::CreateLocalLocal());
-  dispatcher0->Init(message_pipe, 0);
-  dispatcher1->Init(message_pipe, 1);
+  PlatformChannelPair channel_pair;
+  dispatcher0->Init(channel_pair.PassServerHandle());
+  dispatcher1->Init(channel_pair.PassClientHandle());
 
-  message_pipe_handle0.Put(handle_pair.first);
-  message_pipe_handle1.Put(handle_pair.second);
+  *message_pipe_handle0 = handle_pair.first;
+  *message_pipe_handle1 = handle_pair.second;
   return MOJO_RESULT_OK;
 }
 
@@ -239,9 +230,9 @@ MojoResult Core::CreateMessagePipe(
 // after the the message has been received and a new handle created (and
 // possibly even after calls have been made on the new handle).
 MojoResult Core::WriteMessage(MojoHandle message_pipe_handle,
-                              UserPointer<const void> bytes,
+                              const void* bytes,
                               uint32_t num_bytes,
-                              UserPointer<const MojoHandle> handles,
+                              const MojoHandle* handles,
                               uint32_t num_handles,
                               MojoWriteMessageFlags flags) {
   scoped_refptr<Dispatcher> dispatcher(GetDispatcher(message_pipe_handle));
@@ -263,8 +254,6 @@ MojoResult Core::WriteMessage(MojoHandle message_pipe_handle,
   if (num_handles > GetConfiguration().max_message_num_handles)
     return MOJO_RESULT_RESOURCE_EXHAUSTED;
 
-  UserPointer<const MojoHandle>::Reader handles_reader(handles, num_handles);
-
   // We'll need to hold on to the dispatchers so that we can pass them on to
   // |WriteMessage()| and also so that we can unlock their locks afterwards
   // without accessing the handle table. These can be dumb pointers, since their
@@ -276,10 +265,9 @@ MojoResult Core::WriteMessage(MojoHandle message_pipe_handle,
   // and mark the handles as busy. If the call succeeds, we then remove the
   // handles from the handle table.
   {
-    MutexLocker locker(&handle_table_mutex_);
+    base::AutoLock locker(handle_table_lock_);
     MojoResult result = handle_table_.MarkBusyAndStartTransport(
-        message_pipe_handle, handles_reader.GetPointer(), num_handles,
-        &transports);
+        message_pipe_handle, handles, num_handles, &transports);
     if (result != MOJO_RESULT_OK)
       return result;
   }
@@ -293,12 +281,11 @@ MojoResult Core::WriteMessage(MojoHandle message_pipe_handle,
     transports[i].End();
 
   {
-    MutexLocker locker(&handle_table_mutex_);
+    base::AutoLock locker(handle_table_lock_);
     if (rv == MOJO_RESULT_OK) {
-      handle_table_.RemoveBusyHandles(handles_reader.GetPointer(), num_handles);
+      handle_table_.RemoveBusyHandles(handles, num_handles);
     } else {
-      handle_table_.RestoreBusyHandles(handles_reader.GetPointer(),
-                                       num_handles);
+      handle_table_.RestoreBusyHandles(handles, num_handles);
     }
   }
 
@@ -306,18 +293,17 @@ MojoResult Core::WriteMessage(MojoHandle message_pipe_handle,
 }
 
 MojoResult Core::ReadMessage(MojoHandle message_pipe_handle,
-                             UserPointer<void> bytes,
-                             UserPointer<uint32_t> num_bytes,
-                             UserPointer<MojoHandle> handles,
-                             UserPointer<uint32_t> num_handles,
+                             void* bytes,
+                             uint32_t* num_bytes,
+                             MojoHandle* handles,
+                             uint32_t* num_handles,
                              MojoReadMessageFlags flags) {
   scoped_refptr<Dispatcher> dispatcher(GetDispatcher(message_pipe_handle));
   if (!dispatcher)
     return MOJO_RESULT_INVALID_ARGUMENT;
 
-  uint32_t num_handles_value = num_handles.IsNull() ? 0 : num_handles.Get();
-
   MojoResult rv;
+  uint32_t num_handles_value = num_handles ? *num_handles : 0;
   if (num_handles_value == 0) {
     // Easy case: won't receive any handles.
     rv = dispatcher->ReadMessage(bytes, num_bytes, nullptr, &num_handles_value,
@@ -328,20 +314,15 @@ MojoResult Core::ReadMessage(MojoHandle message_pipe_handle,
                                  &num_handles_value, flags);
     if (!dispatchers.empty()) {
       DCHECK_EQ(rv, MOJO_RESULT_OK);
-      DCHECK(!num_handles.IsNull());
+      DCHECK(num_handles);
       DCHECK_LE(dispatchers.size(), static_cast<size_t>(num_handles_value));
 
       bool success;
-      UserPointer<MojoHandle>::Writer handles_writer(handles,
-                                                     dispatchers.size());
       {
-        MutexLocker locker(&handle_table_mutex_);
-        success = handle_table_.AddDispatcherVector(
-            dispatchers, handles_writer.GetPointer());
+        base::AutoLock locker(handle_table_lock_);
+        success = handle_table_.AddDispatcherVector(dispatchers, handles);
       }
-      if (success) {
-        handles_writer.Commit();
-      } else {
+      if (!success) {
         LOG(ERROR) << "Received message with " << dispatchers.size()
                    << " handles, but handle table full";
         // Close dispatchers (outside the lock).
@@ -355,15 +336,15 @@ MojoResult Core::ReadMessage(MojoHandle message_pipe_handle,
     }
   }
 
-  if (!num_handles.IsNull())
-    num_handles.Put(num_handles_value);
+  if (num_handles)
+    *num_handles = num_handles_value;
   return rv;
 }
 
 MojoResult Core::CreateDataPipe(
-    UserPointer<const MojoCreateDataPipeOptions> options,
-    UserPointer<MojoHandle> data_pipe_producer_handle,
-    UserPointer<MojoHandle> data_pipe_consumer_handle) {
+    const MojoCreateDataPipeOptions* options,
+    MojoHandle* data_pipe_producer_handle,
+    MojoHandle* data_pipe_consumer_handle) {
   MojoCreateDataPipeOptions validated_options = {};
   MojoResult result =
       DataPipe::ValidateCreateOptions(options, &validated_options);
@@ -371,13 +352,13 @@ MojoResult Core::CreateDataPipe(
     return result;
 
   scoped_refptr<DataPipeProducerDispatcher> producer_dispatcher =
-      DataPipeProducerDispatcher::Create();
+      DataPipeProducerDispatcher::Create(validated_options);
   scoped_refptr<DataPipeConsumerDispatcher> consumer_dispatcher =
-      DataPipeConsumerDispatcher::Create();
+      DataPipeConsumerDispatcher::Create(validated_options);
 
   std::pair<MojoHandle, MojoHandle> handle_pair;
   {
-    MutexLocker locker(&handle_table_mutex_);
+    base::AutoLock locker(handle_table_lock_);
     handle_pair = handle_table_.AddDispatcherPair(producer_dispatcher,
                                                   consumer_dispatcher);
   }
@@ -390,18 +371,18 @@ MojoResult Core::CreateDataPipe(
   }
   DCHECK_NE(handle_pair.second, MOJO_HANDLE_INVALID);
 
-  scoped_refptr<DataPipe> data_pipe(DataPipe::CreateLocal(validated_options));
-  producer_dispatcher->Init(data_pipe);
-  consumer_dispatcher->Init(data_pipe);
+  PlatformChannelPair channel_pair;
+  producer_dispatcher->Init(channel_pair.PassServerHandle());
+  consumer_dispatcher->Init(channel_pair.PassClientHandle());
 
-  data_pipe_producer_handle.Put(handle_pair.first);
-  data_pipe_consumer_handle.Put(handle_pair.second);
+  *data_pipe_producer_handle = handle_pair.first;
+  *data_pipe_consumer_handle = handle_pair.second;
   return MOJO_RESULT_OK;
 }
 
 MojoResult Core::WriteData(MojoHandle data_pipe_producer_handle,
-                           UserPointer<const void> elements,
-                           UserPointer<uint32_t> num_bytes,
+                           const void* elements,
+                           uint32_t* num_bytes,
                            MojoWriteDataFlags flags) {
   scoped_refptr<Dispatcher> dispatcher(
       GetDispatcher(data_pipe_producer_handle));
@@ -412,8 +393,8 @@ MojoResult Core::WriteData(MojoHandle data_pipe_producer_handle,
 }
 
 MojoResult Core::BeginWriteData(MojoHandle data_pipe_producer_handle,
-                                UserPointer<void*> buffer,
-                                UserPointer<uint32_t> buffer_num_bytes,
+                                void** buffer,
+                                uint32_t* buffer_num_bytes,
                                 MojoWriteDataFlags flags) {
   scoped_refptr<Dispatcher> dispatcher(
       GetDispatcher(data_pipe_producer_handle));
@@ -434,8 +415,8 @@ MojoResult Core::EndWriteData(MojoHandle data_pipe_producer_handle,
 }
 
 MojoResult Core::ReadData(MojoHandle data_pipe_consumer_handle,
-                          UserPointer<void> elements,
-                          UserPointer<uint32_t> num_bytes,
+                          void* elements,
+                          uint32_t* num_bytes,
                           MojoReadDataFlags flags) {
   scoped_refptr<Dispatcher> dispatcher(
       GetDispatcher(data_pipe_consumer_handle));
@@ -446,8 +427,8 @@ MojoResult Core::ReadData(MojoHandle data_pipe_consumer_handle,
 }
 
 MojoResult Core::BeginReadData(MojoHandle data_pipe_consumer_handle,
-                               UserPointer<const void*> buffer,
-                               UserPointer<uint32_t> buffer_num_bytes,
+                               const void** buffer,
+                               uint32_t* buffer_num_bytes,
                                MojoReadDataFlags flags) {
   scoped_refptr<Dispatcher> dispatcher(
       GetDispatcher(data_pipe_consumer_handle));
@@ -468,9 +449,9 @@ MojoResult Core::EndReadData(MojoHandle data_pipe_consumer_handle,
 }
 
 MojoResult Core::CreateSharedBuffer(
-    UserPointer<const MojoCreateSharedBufferOptions> options,
+    const MojoCreateSharedBufferOptions* options,
     uint64_t num_bytes,
-    UserPointer<MojoHandle> shared_buffer_handle) {
+    MojoHandle* shared_buffer_handle) {
   MojoCreateSharedBufferOptions validated_options = {};
   MojoResult result = SharedBufferDispatcher::ValidateCreateOptions(
       options, &validated_options);
@@ -485,21 +466,20 @@ MojoResult Core::CreateSharedBuffer(
     return result;
   }
 
-  MojoHandle h = AddDispatcher(dispatcher);
-  if (h == MOJO_HANDLE_INVALID) {
+  *shared_buffer_handle = AddDispatcher(dispatcher);
+  if (*shared_buffer_handle == MOJO_HANDLE_INVALID) {
     LOG(ERROR) << "Handle table full";
     dispatcher->Close();
     return MOJO_RESULT_RESOURCE_EXHAUSTED;
   }
 
-  shared_buffer_handle.Put(h);
   return MOJO_RESULT_OK;
 }
 
 MojoResult Core::DuplicateBufferHandle(
     MojoHandle buffer_handle,
-    UserPointer<const MojoDuplicateBufferHandleOptions> options,
-    UserPointer<MojoHandle> new_buffer_handle) {
+    const MojoDuplicateBufferHandleOptions* options,
+    MojoHandle* new_buffer_handle) {
   scoped_refptr<Dispatcher> dispatcher(GetDispatcher(buffer_handle));
   if (!dispatcher)
     return MOJO_RESULT_INVALID_ARGUMENT;
@@ -511,27 +491,26 @@ MojoResult Core::DuplicateBufferHandle(
   if (result != MOJO_RESULT_OK)
     return result;
 
-  MojoHandle new_handle = AddDispatcher(new_dispatcher);
-  if (new_handle == MOJO_HANDLE_INVALID) {
+  *new_buffer_handle = AddDispatcher(new_dispatcher);
+  if (*new_buffer_handle == MOJO_HANDLE_INVALID) {
     LOG(ERROR) << "Handle table full";
     dispatcher->Close();
     return MOJO_RESULT_RESOURCE_EXHAUSTED;
   }
 
-  new_buffer_handle.Put(new_handle);
   return MOJO_RESULT_OK;
 }
 
 MojoResult Core::MapBuffer(MojoHandle buffer_handle,
                            uint64_t offset,
                            uint64_t num_bytes,
-                           UserPointer<void*> buffer,
+                           void** buffer,
                            MojoMapBufferFlags flags) {
   scoped_refptr<Dispatcher> dispatcher(GetDispatcher(buffer_handle));
   if (!dispatcher)
     return MOJO_RESULT_INVALID_ARGUMENT;
 
-  scoped_ptr<embedder::PlatformSharedBufferMapping> mapping;
+  scoped_ptr<PlatformSharedBufferMapping> mapping;
   MojoResult result = dispatcher->MapBuffer(offset, num_bytes, flags, &mapping);
   if (result != MOJO_RESULT_OK)
     return result;
@@ -539,19 +518,19 @@ MojoResult Core::MapBuffer(MojoHandle buffer_handle,
   DCHECK(mapping);
   void* address = mapping->GetBase();
   {
-    MutexLocker locker(&mapping_table_mutex_);
+    base::AutoLock locker(mapping_table_lock_);
     result = mapping_table_.AddMapping(mapping.Pass());
   }
   if (result != MOJO_RESULT_OK)
     return result;
 
-  buffer.Put(address);
+  *buffer = address;
   return MOJO_RESULT_OK;
 }
 
-MojoResult Core::UnmapBuffer(UserPointer<void> buffer) {
-  MutexLocker locker(&mapping_table_mutex_);
-  return mapping_table_.RemoveMapping(buffer.GetPointerValue());
+MojoResult Core::UnmapBuffer(void* buffer) {
+  base::AutoLock locker(mapping_table_lock_);
+  return mapping_table_.RemoveMapping(buffer);
 }
 
 // Note: We allow |handles| to repeat the same handle multiple times, since
@@ -564,15 +543,20 @@ MojoResult Core::WaitManyInternal(const MojoHandle* handles,
                                   MojoDeadline deadline,
                                   uint32_t* result_index,
                                   HandleSignalsState* signals_states) {
+  CHECK(handles);
+  CHECK(signals);
   DCHECK_GT(num_handles, 0u);
-  DCHECK_EQ(*result_index, static_cast<uint32_t>(-1));
+  if (result_index) {
+    DCHECK_EQ(*result_index, static_cast<uint32_t>(-1));
+  }
 
   DispatcherVector dispatchers;
   dispatchers.reserve(num_handles);
   for (uint32_t i = 0; i < num_handles; i++) {
     scoped_refptr<Dispatcher> dispatcher = GetDispatcher(handles[i]);
     if (!dispatcher) {
-      *result_index = i;
+      if (result_index && result_index)

[brucedawson, 2015/10/05 16:50:26]

The /analyze builder points out that this line of code is wrong or confusing.
The same condition is checked twice. I'm not sure what the intent is. The
warning, FWIW, is:

src\mojo\edk\system\core.cc(549) : warning C6287: Redundant code:  the left and
right sub-expressions are identical.

+        *result_index = i;
       return MOJO_RESULT_INVALID_ARGUMENT;
     }
     dispatchers.push_back(dispatcher);
@@ -588,7 +572,8 @@ MojoResult Core::WaitManyInternal(const MojoHandle* handles,
     rv = dispatchers[i]->AddAwakable(
         &waiter, signals[i], i, signals_states ? &signals_states[i] : nullptr);
     if (rv != MOJO_RESULT_OK) {
-      *result_index = i;
+      if (result_index)
+        *result_index = i;
       break;
     }
   }
@@ -614,5 +599,5 @@ MojoResult Core::WaitManyInternal(const MojoHandle* handles,
   return rv;
 }
 
-}  // namespace system
+}  // namespace edk
 }  // namespace mojo