Convert ReadData...() to use the new user pointer handling (see r285350).

mojo/system/data_pipe.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "mojo/system/data_pipe.h"
 
 #include <string.h>
 
 #include <algorithm>
 #include <limits>
@@ skipping 212 matching lines @@
   consumer_waiter_list_.reset();
   // Not a bug, except possibly in "user" code.
   DVLOG_IF(2, consumer_in_two_phase_read_no_lock())
       << "Consumer closed with active two-phase read";
   consumer_two_phase_max_num_bytes_read_ = 0;
   ConsumerCloseImplNoLock();
   AwakeProducerWaitersForStateChangeNoLock(
       ProducerGetHandleSignalsStateNoLock());
 }
 
-MojoResult DataPipe::ConsumerReadData(void* elements,
-                                      uint32_t* num_bytes,
+MojoResult DataPipe::ConsumerReadData(UserPointer<void> elements,
+                                      UserPointer<uint32_t> num_bytes,
                                       bool all_or_none) {
   base::AutoLock locker(lock_);
   DCHECK(has_local_consumer_no_lock());
 
   if (consumer_in_two_phase_read_no_lock())
     return MOJO_RESULT_BUSY;
 
-  if (*num_bytes % element_num_bytes_ != 0)
+  uint32_t max_num_bytes_to_read = num_bytes.Get();
+  if (max_num_bytes_to_read % element_num_bytes_ != 0)
     return MOJO_RESULT_INVALID_ARGUMENT;
 
-  if (*num_bytes == 0)
+  if (max_num_bytes_to_read == 0)
     return MOJO_RESULT_OK;  // Nothing to do.
 
+  uint32_t min_num_bytes_to_read = all_or_none ? max_num_bytes_to_read : 0;
+
   HandleSignalsState old_producer_state = ProducerGetHandleSignalsStateNoLock();
-  MojoResult rv = ConsumerReadDataImplNoLock(elements, num_bytes, all_or_none);
+  MojoResult rv = ConsumerReadDataImplNoLock(elements, num_bytes,
+                                             max_num_bytes_to_read,
+                                             min_num_bytes_to_read);
   HandleSignalsState new_producer_state = ProducerGetHandleSignalsStateNoLock();
   if (!new_producer_state.equals(old_producer_state))
     AwakeProducerWaitersForStateChangeNoLock(new_producer_state);
   return rv;
 }
 
-MojoResult DataPipe::ConsumerDiscardData(uint32_t* num_bytes,
+MojoResult DataPipe::ConsumerDiscardData(UserPointer<uint32_t> num_bytes,
                                          bool all_or_none) {
   base::AutoLock locker(lock_);
   DCHECK(has_local_consumer_no_lock());
 
   if (consumer_in_two_phase_read_no_lock())
     return MOJO_RESULT_BUSY;
 
-  if (*num_bytes % element_num_bytes_ != 0)
+  uint32_t max_num_bytes_to_discard = num_bytes.Get();
+  if (max_num_bytes_to_discard % element_num_bytes_ != 0)
     return MOJO_RESULT_INVALID_ARGUMENT;
 
-  if (*num_bytes == 0)
+  if (max_num_bytes_to_discard == 0)
     return MOJO_RESULT_OK;  // Nothing to do.
 
+  uint32_t min_num_bytes_to_discard = all_or_none ? max_num_bytes_to_discard :
+                                                    0;
+
   HandleSignalsState old_producer_state = ProducerGetHandleSignalsStateNoLock();
-  MojoResult rv = ConsumerDiscardDataImplNoLock(num_bytes, all_or_none);
+  MojoResult rv = ConsumerDiscardDataImplNoLock(num_bytes,
+                                                max_num_bytes_to_discard,
+                                                min_num_bytes_to_discard);
   HandleSignalsState new_producer_state = ProducerGetHandleSignalsStateNoLock();
   if (!new_producer_state.equals(old_producer_state))
     AwakeProducerWaitersForStateChangeNoLock(new_producer_state);
   return rv;
 }
 
-MojoResult DataPipe::ConsumerQueryData(uint32_t* num_bytes) {
+MojoResult DataPipe::ConsumerQueryData(UserPointer<uint32_t> num_bytes) {
   base::AutoLock locker(lock_);
   DCHECK(has_local_consumer_no_lock());
 
   if (consumer_in_two_phase_read_no_lock())
     return MOJO_RESULT_BUSY;
 
   // Note: Don't need to validate |*num_bytes| for query.
   return ConsumerQueryDataImplNoLock(num_bytes);
 }
 
@@ skipping 115 matching lines @@
 void DataPipe::AwakeConsumerWaitersForStateChangeNoLock(
     const HandleSignalsState& new_consumer_state) {
   lock_.AssertAcquired();
   if (!has_local_consumer_no_lock())
     return;
   consumer_waiter_list_->AwakeWaitersForStateChange(new_consumer_state);
 }
 
 }  // namespace system
 }  // namespace mojo