upload android base code part6

android/system/connectivity/wifilogd/main_loop.cpp

@@ -0,0 +1,87 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <array>
+#include <cstdint>
+#include <cstring>
+#include <memory>
+#include <utility>
+
+#include "android-base/logging.h"
+
+#include "wifilogd/main_loop.h"
+#include "wifilogd/protocol.h"
+
+namespace android {
+namespace wifilogd {
+
+namespace {
+constexpr auto kMainBufferSizeBytes = 128 * 1024;
+// TODO(b/32840641): Tune the sleep time.
+constexpr auto kTransientErrorSleepTimeNsec = 100 * 1000;  // 100 usec
+}
+
+MainLoop::MainLoop(const std::string& socket_name)
+    : MainLoop(socket_name, std::make_unique<Os>(),
+               std::make_unique<CommandProcessor>(kMainBufferSizeBytes)) {}
+
+MainLoop::MainLoop(const std::string& socket_name, std::unique_ptr<Os> os,
+                   std::unique_ptr<CommandProcessor> command_processor)
+    : os_(std::move(os)), command_processor_(std::move(command_processor)) {
+  Os::Errno err;
+  std::tie(sock_fd_, err) = os_->GetControlSocket(socket_name);
+  if (err) {
+    LOG(FATAL) << "Failed to get control socket: " << std::strerror(errno);
+  }
+}
+
+void MainLoop::RunOnce() {
+  std::array<uint8_t, protocol::kMaxMessageSize> input_buf;
+  size_t datagram_len;
+  Os::Errno err;
+  std::tie(datagram_len, err) =
+      os_->ReceiveDatagram(sock_fd_, input_buf.data(), input_buf.size());
+  if (err) {
+    ProcessError(err);
+    return;
+  }
+
+  if (datagram_len > protocol::kMaxMessageSize) {
+    // TODO(b/32098735): Increment stats counter.
+    datagram_len = protocol::kMaxMessageSize;
+  }
+
+  command_processor_->ProcessCommand(input_buf.data(), datagram_len,
+                                     Os::kInvalidFd);
+}
+
+// Private methods below.
+
+void MainLoop::ProcessError(Os::Errno err) {
+  if (err == EINTR || err == ENOMEM) {
+    // TODO(b/32098735): Increment stats counter.
+    os_->Nanosleep(kTransientErrorSleepTimeNsec);
+    return;
+  }
+
+  // Any other error is unexpected, and assumed to be non-recoverable.
+  // (If, e.g., our socket is in a bad state, then we won't be able to receive
+  // any new log messages.)
+  LOG(FATAL) << "Unexpected error: " << std::strerror(err);
+}
+
+}  // namespace wifilogd
+}  // namespace android