[XProto] Move SendRequest() into source file

Most of SendRequest doesn't depend on the template parameter |Reply|,
so move the common code into a non-template function defined in the
source file.  This should hopefully reduce binary size since
SendRequest() gets instantiated for every Request type (654 in total).

BUG=1066670
R=sky

Change-Id: Iee5934f42b1c4ceb02b3279452e4cadbb7a620fe
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2268841Reviewed-by: Scott Violet <sky@chromium.org>
Commit-Queue: Thomas Anderson <thomasanderson@chromium.org>
Cr-Commit-Position: refs/heads/master@{#783074}

ui/gfx/x/xproto_internal.cc

@@ -54,4 +54,66 @@ size_t UnretainedRefCountedMemory::size() const {
 
 UnretainedRefCountedMemory::~UnretainedRefCountedMemory() = default;
 
+base::Optional<unsigned int> SendRequestImpl(x11::Connection* connection,
+                                             WriteBuffer* buf,
+                                             bool is_void) {
+  xcb_protocol_request_t xpr{
+      .ext = nullptr,
+      .isvoid = is_void,
+  };
+
+  struct RequestHeader {
+    uint8_t major_opcode;
+    uint8_t minor_opcode;
+    uint16_t length;
+  };
+
+  struct ExtendedRequestHeader {
+    RequestHeader header;
+    uint32_t long_length;
+  };
+  static_assert(sizeof(ExtendedRequestHeader) == 8, "");
+
+  auto& first_buffer = buf->GetBuffers()[0];
+  DCHECK_GE(first_buffer->size(), sizeof(RequestHeader));
+  auto* old_header = reinterpret_cast<RequestHeader*>(
+      const_cast<uint8_t*>(first_buffer->data()));
+  ExtendedRequestHeader new_header{*old_header, 0};
+
+  // Requests are always a multiple of 4 bytes on the wire.  Because of this,
+  // the length field represents the size in chunks of 4 bytes.
+  DCHECK_EQ(buf->offset() % 4, 0UL);
+  size_t size32 = buf->offset() / 4;
+
+  // XCB requires 2 iovecs for its own internal usage.
+  std::vector<struct iovec> io{{nullptr, 0}, {nullptr, 0}};
+  if (size32 < connection->setup().maximum_request_length) {
+    // Regular request
+    old_header->length = size32;
+  } else if (size32 < connection->extended_max_request_length()) {
+    // BigRequests extension request
+    DCHECK_EQ(new_header.header.length, 0U);
+    new_header.long_length = size32 + 1;
+
+    io.push_back({&new_header, sizeof(ExtendedRequestHeader)});
+    first_buffer = base::MakeRefCounted<OffsetRefCountedMemory>(
+        first_buffer, sizeof(RequestHeader),
+        first_buffer->size() - sizeof(RequestHeader));
+  } else {
+    LOG(ERROR) << "Cannot send request of length " << buf->offset();
+    return base::nullopt;
+  }
+
+  for (auto& buffer : buf->GetBuffers())
+    io.push_back({const_cast<uint8_t*>(buffer->data()), buffer->size()});
+  xpr.count = io.size() - 2;
+
+  xcb_connection_t* conn = connection->XcbConnection();
+  auto flags = XCB_REQUEST_CHECKED | XCB_REQUEST_RAW;
+  auto sequence = xcb_send_request(conn, flags, &io[2], &xpr);
+  if (xcb_connection_has_error(conn))
+    return base::nullopt;
+  return sequence;
+}
+
 }  // namespace x11

ui/gfx/x/xproto_internal.h

@@ -136,68 +136,14 @@ inline void Align(ReadBuffer* buf, size_t align) {
   Pad(buf, (align - (buf->offset % align)) % align);
 }
 
+base::Optional<unsigned int> SendRequestImpl(x11::Connection* connection,
+                                             WriteBuffer* buf,
+                                             bool is_void);
+
 template <typename Reply>
 Future<Reply> SendRequest(x11::Connection* connection, WriteBuffer* buf) {
-  // Clang crashes when the value of |is_void| is inlined below,
-  // so keep this variable outside of |xpr|.
-  constexpr bool is_void = std::is_void<Reply>::value;
-  xcb_protocol_request_t xpr{
-      .ext = nullptr,
-      .isvoid = is_void,
-  };
-
-  struct RequestHeader {
-    uint8_t major_opcode;
-    uint8_t minor_opcode;
-    uint16_t length;
-  };
-
-  struct ExtendedRequestHeader {
-    RequestHeader header;
-    uint32_t long_length;
-  };
-  static_assert(sizeof(ExtendedRequestHeader) == 8, "");
-
-  auto& first_buffer = buf->GetBuffers()[0];
-  DCHECK_GE(first_buffer->size(), sizeof(RequestHeader));
-  auto* old_header = reinterpret_cast<RequestHeader*>(
-      const_cast<uint8_t*>(first_buffer->data()));
-  ExtendedRequestHeader new_header{*old_header, 0};
-
-  // Requests are always a multiple of 4 bytes on the wire.  Because of this,
-  // the length field represents the size in chunks of 4 bytes.
-  DCHECK_EQ(buf->offset() % 4, 0UL);
-  size_t size32 = buf->offset() / 4;
-
-  // XCB requires 2 iovecs for its own internal usage.
-  std::vector<struct iovec> io{{nullptr, 0}, {nullptr, 0}};
-  if (size32 < connection->setup().maximum_request_length) {
-    // Regular request
-    old_header->length = size32;
-  } else if (size32 < connection->extended_max_request_length()) {
-    // BigRequests extension request
-    DCHECK_EQ(new_header.header.length, 0U);
-    new_header.long_length = size32 + 1;
-
-    io.push_back({&new_header, sizeof(ExtendedRequestHeader)});
-    first_buffer = base::MakeRefCounted<OffsetRefCountedMemory>(
-        first_buffer, sizeof(RequestHeader),
-        first_buffer->size() - sizeof(RequestHeader));
-  } else {
-    LOG(ERROR) << "Cannot send request of length " << buf->offset();
-    return {nullptr, base::nullopt};
-  }
-
-  for (auto& buffer : buf->GetBuffers())
-    io.push_back({const_cast<uint8_t*>(buffer->data()), buffer->size()});
-  xpr.count = io.size() - 2;
-
-  xcb_connection_t* conn = connection->XcbConnection();
-  auto flags = XCB_REQUEST_CHECKED | XCB_REQUEST_RAW;
-  auto sequence = xcb_send_request(conn, flags, &io[2], &xpr);
-  if (xcb_connection_has_error(conn))
-    return {nullptr, base::nullopt};
-  return {connection, sequence};
+  auto sequence = SendRequestImpl(connection, buf, std::is_void<Reply>::value);
+  return {sequence ? connection : nullptr, sequence};
 }
 
 // Helper function for xcbproto popcount.  Given an integral type, returns the