Dart: Merge message pipe query and read into one native call

mojo/public/platform/dart/mojo_natives.cc

 // Copyright 2014 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 <stdio.h>
 #include <string.h>
 
 #include <memory>
 #include <vector>
 
@@ skipping 19 matching lines @@
   V(MojoDataPipe_Create, 3)                \
   V(MojoDataPipe_WriteData, 4)             \
   V(MojoDataPipe_BeginWriteData, 3)        \
   V(MojoDataPipe_EndWriteData, 2)          \
   V(MojoDataPipe_ReadData, 4)              \
   V(MojoDataPipe_BeginReadData, 3)         \
   V(MojoDataPipe_EndReadData, 2)           \
   V(MojoMessagePipe_Create, 1)             \
   V(MojoMessagePipe_Write, 5)              \
   V(MojoMessagePipe_Read, 5)               \
+  V(MojoMessagePipe_QueryAndRead, 5)       \
   V(Mojo_GetTimeTicksNow, 0)               \
   V(MojoHandle_Close, 1)                   \
   V(MojoHandle_Wait, 3)                    \
   V(MojoHandle_RegisterFinalizer, 2)       \
   V(MojoHandle_WaitMany, 3)                \
   V(MojoHandleWatcher_GrowStateArrays, 1)  \
   V(MojoHandleWatcher_WaitMany, 2)         \
   V(MojoHandleWatcher_SendControlData, 4)  \
   V(MojoHandleWatcher_RecvControlData, 1)  \
   V(MojoHandleWatcher_SetControlHandle, 1) \
@@ skipping 661 matching lines @@
     }
   }
 
   Dart_Handle list = Dart_NewList(3);
   Dart_ListSetAt(list, 0, Dart_NewInteger(res));
   Dart_ListSetAt(list, 1, Dart_NewInteger(blen));
   Dart_ListSetAt(list, 2, Dart_NewInteger(hlen));
   Dart_SetReturnValue(arguments, list);
 }
 
+void MojoMessagePipe_QueryAndRead(Dart_NativeArguments arguments) {
+  Dart_Handle err;
+  int64_t dart_handle;
+  int64_t flags = 0;
+  CHECK_INTEGER_ARGUMENT(arguments, 0, &dart_handle, Null);
+  CHECK_INTEGER_ARGUMENT(arguments, 1, &flags, Null);
+
+  Dart_Handle data = Dart_GetNativeArgument(arguments, 2);
+  Dart_Handle handles = Dart_GetNativeArgument(arguments, 3);
+  Dart_Handle result = Dart_GetNativeArgument(arguments, 4);
+
+  // Query the number of bytes and handles available.
+  uint32_t blen = 0;
+  uint32_t hlen = 0;
+  MojoResult res =
+      MojoReadMessage(static_cast<MojoHandle>(dart_handle), nullptr, &blen,
+                      nullptr, &hlen, static_cast<MojoReadMessageFlags>(flags));
+
+  if ((res != MOJO_RESULT_OK) && (res != MOJO_RESULT_RESOURCE_EXHAUSTED)) {
+    Dart_ListSetAt(result, 0, Dart_NewInteger(res));
+    Dart_ListSetAt(result, 1, data);
+    Dart_ListSetAt(result, 2, handles);
+    Dart_ListSetAt(result, 3, Dart_NewInteger(0));
+    Dart_ListSetAt(result, 4, Dart_NewInteger(0));
+    return;
+  }
+
+  Dart_TypedData_Type typ;
+  void* bytes = nullptr;
+  intptr_t bytes_len = 0;
+  if ((blen > 0) && Dart_IsNull(data)) {
+    data = Dart_NewTypedData(Dart_TypedData_kByteData, blen);

[Cutch, 2015/11/06 21:59:15]

Make this external to avoid a copy at every acquire.

[zra, 2015/11/06 23:35:42]

Done.

+  } else if (blen > 0) {
+    err = Dart_TypedDataAcquireData(data, &typ, &bytes, &bytes_len);
+    MOJO_DCHECK(!Dart_IsError(err));
+    err = Dart_TypedDataReleaseData(data);
+    MOJO_DCHECK(!Dart_IsError(err));
+    if (static_cast<uintptr_t>(bytes_len) < blen) {
+      data = Dart_NewTypedData(Dart_TypedData_kByteData, blen);
+    }
+  }
+
+  void* handle_bytes = nullptr;
+  intptr_t handles_len = 0;
+  if ((hlen > 0) && Dart_IsNull(handles)) {
+    handles = Dart_NewTypedData(Dart_TypedData_kUint32, hlen);

[Cutch, 2015/11/06 21:59:15]

Make this external to avoid a copy at every acquire.

[zra, 2015/11/06 23:35:42]

Done.

+  } else if (hlen > 0) {
+    err = Dart_TypedDataAcquireData(handles, &typ, &handle_bytes, &handles_len);
+    MOJO_DCHECK(!Dart_IsError(err));
+    err = Dart_TypedDataReleaseData(handles);
+    MOJO_DCHECK(!Dart_IsError(err));
+    if (static_cast<uintptr_t>(handles_len) < hlen) {
+      handles = Dart_NewTypedData(Dart_TypedData_kUint32, hlen);
+    }
+  }
+
+  if (blen > 0) {
+    err = Dart_TypedDataAcquireData(data, &typ, &bytes, &bytes_len);
+    MOJO_DCHECK(!Dart_IsError(err));
+  }
+
+  if (hlen > 0) {
+    err = Dart_TypedDataAcquireData(handles, &typ, &handle_bytes, &handles_len);
+    MOJO_DCHECK(!Dart_IsError(err));
+  }
+
+  res = MojoReadMessage(static_cast<MojoHandle>(dart_handle), bytes, &blen,
+                        reinterpret_cast<MojoHandle*>(handle_bytes), &hlen,
+                        static_cast<MojoReadMessageFlags>(flags));
+
+  if (blen > 0) {
+    err = Dart_TypedDataReleaseData(data);
+    MOJO_DCHECK(!Dart_IsError(err));
+  }
+
+  if (hlen > 0) {
+    err = Dart_TypedDataReleaseData(handles);
+    MOJO_DCHECK(!Dart_IsError(err));
+  }
+
+  Dart_ListSetAt(result, 0, Dart_NewInteger(res));
+  Dart_ListSetAt(result, 1, data);
+  Dart_ListSetAt(result, 2, handles);
+  Dart_ListSetAt(result, 3, Dart_NewInteger(blen));
+  Dart_ListSetAt(result, 4, Dart_NewInteger(hlen));
+}
+
 struct MojoWaitManyState {
   MojoWaitManyState() {}
 
   std::vector<uint32_t> handles;
   std::vector<uint32_t> signals;
   std::vector<uint32_t> out_index;
   std::vector<MojoHandleSignalsState> out_signals;
 
   static MojoWaitManyState* GetInstance();
 
@@ skipping 162 matching lines @@
   mojo_control_handle = control_handle;
   Dart_SetIntegerReturnValue(arguments, static_cast<int64_t>(MOJO_RESULT_OK));
 }
 
 void MojoHandleWatcher_GetControlHandle(Dart_NativeArguments arguments) {
   Dart_SetIntegerReturnValue(arguments, mojo_control_handle);
 }
 
 }  // namespace dart
 }  // namespace mojo